tag:theconversation.com,2011:/id/topics/water-supply-25688/articlesWater supply – The Conversation2024-02-22T19:20:21Ztag:theconversation.com,2011:article/2218532024-02-22T19:20:21Z2024-02-22T19:20:21ZEmissions from households’ water use are on a par with aviation. The big cuts and savings they can make are being neglected<figure><img src="https://images.theconversation.com/files/574310/original/file-20240208-30-fmpr5b.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5472%2C3637&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/beautiful-woman-taking-shower-her-bathroom-1169109334">hedgehog94/Shutterstock</a></span></figcaption></figure><p>Why is there such a big gap between people, industries and government agreeing we need urgent action on climate change, and actually starting? Scope 3 emissions are a great example. These are greenhouse gas emissions that organisations can influence, but don’t directly control. </p>
<p><a href="https://www.monash.edu/msdi/initiatives/reports/net-zero-carbon-water-cycle">Our research</a> has identified the benefits of tackling these emissions in Australia’s urban water sector. If we consider the energy we use to heat water, water costs us far more than we think. It’s an issue of cost of living as well as water supply and energy infrastructure. </p>
<p>In Victoria, for example, water utilities are the <a href="https://www.water.vic.gov.au/our-programs/climate-change-and-victorias-water-sector/greenhouse-gas-emissions-from-the-water-sector">largest source</a> (about a quarter) of scope 1 and 2 emissions from the government sector. Scope 1 emissions come from activities utilities directly control, such as driving their vehicles. Scope 2 emissions are from the energy they buy. </p>
<p>Our research has found the gains from pursuing scope 3 emissions from the use of water that utilities supply could be about ten times bigger than their planned reductions in scope 1 and 2 emissions.</p>
<p>Extrapolating from Melbourne household data suggests domestic water heating accounts for <a href="https://www.monash.edu/__data/assets/pdf_file/0010/3532852/1.2.1-NZCWC-Synthesis-Report.pdf">3.8% of each person’s share</a> of Australia’s greenhouse gas emissions – on a par with the 4.1% from aviation. <a href="https://www.monash.edu/__data/assets/pdf_file/0010/3532852/1.2.1-NZCWC-Synthesis-Report.pdf">Our research</a> indicates that in Melbourne alone a city-wide program to retrofit showerheads could, by reducing water and energy use, have the same impact on emissions as taking tens of thousands of cars off the road. </p>
<p>Such a program would cost much less than all other renewable energy investments water utilities are making. It would also save water users money.</p>
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<h2>How to tackle scope 3 emissions</h2>
<p>Water utilities don’t directly control scope 3 emissions, but they could influence what customers do. If they <a href="https://www.monash.edu/__data/assets/pdf_file/0010/3532852/1.2.1-NZCWC-Synthesis-Report.pdf">encourage more efficient water use</a>, <a href="https://www.wsaa.asn.au/sites/default/files/publication/download/Transitioning%20the%20water%20industry%20with%20the%20circular%20economy%20FINAL%2012102020.pdf">customers use less water</a> and, in turn, less energy to heat it. </p>
<p>Water utilities account for <a href="https://www.water.vic.gov.au/our-programs/climate-change-and-victorias-water-sector/greenhouse-gas-emissions-from-the-water-sector">24% of scope 1 and 2 emissions</a> from the Victorian government sector. While the sector has shown leadership in acting on these emissions, there is very little active accountability for, or even quantification of, scope 3 emissions. </p>
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<a href="https://images.theconversation.com/files/576106/original/file-20240216-22-y339jn.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Graph showing the sources of stage 1 and 2 emissions from the Victorian water sector" src="https://images.theconversation.com/files/576106/original/file-20240216-22-y339jn.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576106/original/file-20240216-22-y339jn.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=737&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576106/original/file-20240216-22-y339jn.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=737&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576106/original/file-20240216-22-y339jn.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=737&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576106/original/file-20240216-22-y339jn.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=927&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576106/original/file-20240216-22-y339jn.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=927&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576106/original/file-20240216-22-y339jn.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=927&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="attribution"><a class="source" href="https://www.water.vic.gov.au/our-programs/climate-change-and-victorias-water-sector/greenhouse-gas-emissions-from-the-water-sector">Victorian Department of Energy, Environment and Climate Action</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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<p><a href="https://www.monash.edu/msdi/initiatives/reports/net-zero-carbon-water-cycle">Our research</a> has found a Melbourne-wide program to retrofit showerheads to next-generation technology could save 12-27 billion litres (GL) of water a year (about 6% of current use). </p>
<p>The resulting energy savings would be 380-885GWh per year, cutting emissions by 98,000-226,000 tonnes. That equates to taking 21,000 to 49,000 cars off the roads. </p>
<p>Customers would also save up to $160 a year on their bills. The full economic benefit to society is more than five times the cost of the program.</p>
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<h2>Who influences water use? Everyone</h2>
<p>Helping customers adopt highly efficient showerheads could cut emissions at much lower cost than all other renewable energy investments water utilities are making.</p>
<p>Most households don’t realise hot water systems account for around 24% of their total energy use. Their total <a href="https://www.energyrating.gov.au/industry-information/publications/report-2021-residential-baseline-study-australia-and-new-zealand-2000-2040%20output%20tables%20v1.9.2-AU">energy use for water heating</a> is larger as it includes appliances such as washing machines, dishwashers and kettles. An even larger percentage of household energy use is “water-related” if pool filtration, rainwater tank pumps and so on are included.</p>
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<p>We think only of the savings on water bills, but efficient water use also affects our power bills and emissions. But communicating the link isn’t easy. </p>
<p>Showerhead manufacturers tell us they aren’t promoting efficient showerheads because they respond to demand. Water utilities don’t invest in them because it is a present cost for a future benefit – it doesn’t help them balance their budgets. And for policymakers it’s hard to celebrate the water and energy you don’t need to consume. </p>
<p>The combined impact is lack of action on saving water to reduce emissions – even though it’s a great option.</p>
<h2>A ‘tragedy of the commons’ dilemma</h2>
<p>Without direct control or accountability by any one organisation, we face a “<a href="https://www.britannica.com/science/tragedy-of-the-commons">tragedy of the commons</a>” – individuals overconsuming a shared resource at the wider expense of society. The limited resource today is the ability of our planet to process greenhouse gas emissions before they change our climate. </p>
<p>The tragedy of the commons was used to describe externalities: costs borne by others that a decision-maker does not pay for. Examples include the future costs of increased flooding, more severe droughts and bushfires, and rising sea levels.</p>
<p>If we fully considered the costs and benefits to consumers and society (rather than just costs to utilities), investment priorities would change towards “least cost to the community” solutions. </p>
<p>Many water utilities will be carbon-neutral for scope 1 and 2 by 2025. This means they are at the global forefront of reducing emissions – but the water industry can do much more by tackling scope 3 emissions. </p>
<p>Committing to a scope 3 reduction challenges a water company to move toward things it can only influence rather than control. So, does it pursue all possibilities, without knowing if it can cut emissions? Or does it take a conservative approach and commit to only scope 1 and 2 emissions? </p>
<p>Reducing emissions from water use requires community, industry and government to act together. The stumbling block is decision-making and current legislation.</p>
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<img alt="A road runs along the top of the Thomson Dam wall" src="https://images.theconversation.com/files/575546/original/file-20240214-20-slogv7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/575546/original/file-20240214-20-slogv7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/575546/original/file-20240214-20-slogv7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/575546/original/file-20240214-20-slogv7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/575546/original/file-20240214-20-slogv7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/575546/original/file-20240214-20-slogv7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/575546/original/file-20240214-20-slogv7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Water utilities have focused on cutting their own emissions and costs, neglecting the much bigger gains to be had from changing water users’ behaviour.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/road-over-dam-wall-722054434">Simon Maddock/Shutterstock</a></span>
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<h2>So, what is the solution?</h2>
<p>First, we need to call out the problem. </p>
<p>Second, we must find a way to ensure the reward for pursuing action is higher than the penalty for failure. A key to this will be highlighting how much cheaper and better many actions are that focus on scope 3 emissions, rather than solely “within business” strategies. We need to find solutions that are genuinely “least cost to community” rather than “least cost to individual business entities”.</p>
<p>Third, as a “commons”, this challenge must be communicated beyond utilities and government to communities. There needs to be broad understanding of the benefits of new approaches and of the pitfalls of a “do nothing” approach.</p>
<p>Big savings are up for grabs in the water industry. More broadly, all industries (from manufacturing to mining) need to consider scope 3 emissions from use of the products they sell.</p><img src="https://counter.theconversation.com/content/221853/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Steven Kenway receives funding from the water industry, state and local government, Collaborative Research Centres and competitive funding schemes (eg The Australian Research Council). He is a long-term member of the Australian Water Association and former member of the International Water Association. </span></em></p><p class="fine-print"><em><span>Liam Smith receives funding from several government bodies, including state water utilities and local, state and federal government environment departments. He is also a Lead Councillor on The Biodiversity Council.</span></em></p><p class="fine-print"><em><span>Paul Satur receives funding from a number of public and private associations including water utilities, federal and state governments. He is also the CEO and co-founder of Our Future Cities Inc. </span></em></p><p class="fine-print"><em><span>Rob Skinner does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>More efficient water use is one of the most cost-effective steps we can take to cut emissions.Steven Kenway, Research Group Leader, Water-Energy-Carbon, The University of QueenslandLiam Smith, Director, BehaviourWorks, Monash Sustainable Development Institute, Monash UniversityPaul Satur, Research Fellow for Water Sensitive Cities, Monash Sustainable Development Institute, Monash UniversityRob Skinner, Professorial Fellow, Monash Sustainable Development Institute, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2222492024-01-30T13:36:20Z2024-01-30T13:36:20ZWhat is an atmospheric river? With flooding and mudslides in California, a hydrologist explains the good and bad of these storms and how they’re changing<figure><img src="https://images.theconversation.com/files/572509/original/file-20240131-15-zr0n4c.jpg?ixlib=rb-1.1.0&rect=164%2C18%2C2084%2C1425&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A satellite image shows a powerful atmospheric river hitting the U.S. West Coast on Jan. 31, 2024.</span> <span class="attribution"><a class="source" href="https://cdn.star.nesdis.noaa.gov/GOES18/ABI/CONUS/GEOCOLOR/20240311721_GOES18-ABI-CONUS-GEOCOLOR-2500x1500.jpg">NOAA GOES</a></span></figcaption></figure><p><em>Millions of Californians were <a href="https://www.nbcnews.com/news/weather/live-blog/potentially-life-threatening-storm-system-begins-pounding-california-l-rcna137204">under flood alerts</a> as a <a href="https://cw3e.ucsd.edu/cw3e-ar-update-2-february-2024-outlook/">powerful atmospheric river</a> brought heavy rain to the West Coast in early February 2024. Los Angeles saw <a href="https://images.theconversation.com/files/573527/original/file-20240205-19-ss87hh.png">one of its wettest days on record</a> with over 4 inches of rain on Feb. 4. Other communities were hit by more than 12 inches of rain and reported <a href="https://ktla.com/news/local-news/live-updates-worst-of-storm-moves-into-southern-california/">widespread flooding</a>. <a href="https://www.youtube.com/watch?v=qCEX7nwXwaI">Debris and mudslides</a> shut down <a href="https://twitter.com/CaltransDist7/status/1754525910676697306">sections of highways</a> and <a href="https://laist.com/news/climate-environment/major-storm-heading-into-socal-sunday">roads into Malibu</a>.</em> </p>
<p><em>It was the <a href="https://cw3e.ucsd.edu/cw3e-ar-update-29-january-2024-outlook/">latest in a series</a> of atmospheric rivers to bring extreme rainfall to the West Coast. While these storms are dreaded for the damage they can cause, they are also essential to the region’s water supply, particularly in California, as <a href="https://scholar.google.com/citations?user=aTFYE98AAAAJ&hl=en">Qian Cao</a>, a hydrologist at the University of California, San Diego, explains.</em></p>
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<h2>What are atmospheric rivers?</h2>
<p>An atmospheric river is a narrow corridor or filament of concentrated water vapor transported in the atmosphere. It’s like a river in the sky that can be <a href="https://pubs.usgs.gov/publication/70036359">1,000 miles long</a>. On average, atmospheric rivers have about <a href="https://www.jpl.nasa.gov/news/ranking-atmospheric-rivers-new-study-finds-world-of-potential">twice the regular flow of the Amazon River</a>.</p>
<p>When atmospheric rivers run up against mountains or run into local atmospheric dynamics and are forced to ascend, the moisture they carry cools and condenses, so they can produce intense rainfall or snowfall.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/w3rtYM0HtIM?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A satellite view of atmospheric rivers.</span></figcaption>
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<p>Atmospheric rivers occur all over the world, most commonly in the mid-latitudes. They form when large-scale weather patterns align to create narrow channels, or filaments, of intense moisture transport. These start over warm water, typically tropical oceans, and are guided toward the coast by low-level jet streams ahead of cold fronts of extratropical cyclones.</p>
<p>Along the U.S. West Coast, the Pacific Ocean serves as the reservoir of moisture for the storm, and the mountain ranges act as barriers, which is why the western sides of the coastal ranges and Sierra Nevada see so much rain and snow.</p>
<h2>Why are back-to-back atmospheric rivers a high flood risk?</h2>
<p>Consecutive atmospheric rivers, known as AR families, <a href="https://doi.org/10.1175/JHM-D-18-0217.1">can cause significant flooding</a>.</p>
<p>The first heavy downpours saturate the ground. As <a href="https://doi.org/10.1126/sciadv.abq0995">consecutive storms arrive</a>, their precipitation falls on soil that can’t absorb more water. That contributes to more runoff. Rivers and streams fill up. In the meantime, there may be snowmelt due to warm temperatures, further adding to the runoff and flood risk.</p>
<p>California experienced a <a href="https://theconversation.com/epic-snow-from-all-those-atmospheric-rivers-in-the-west-is-starting-to-melt-and-the-flood-danger-is-rising-203874">historic run</a> of nine consecutive atmospheric rivers in the span of three weeks in December 2022 and January 2023. The storms <a href="https://theconversation.com/is-the-western-drought-finally-ending-that-depends-on-where-you-look-201156">helped bring most reservoirs back</a> to historical averages in 2023 after several drought years, but they also produced damaging <a href="https://www.cbsnews.com/news/california-flooding-landslides-as-atmospheric-river-power-outage">floods and debris flows</a>.</p>
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<img alt="An animation shows filaments of water heading toward the coast." src="https://images.theconversation.com/files/572019/original/file-20240129-21-24vhfq.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/572019/original/file-20240129-21-24vhfq.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=282&fit=crop&dpr=1 600w, https://images.theconversation.com/files/572019/original/file-20240129-21-24vhfq.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=282&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/572019/original/file-20240129-21-24vhfq.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=282&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/572019/original/file-20240129-21-24vhfq.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=354&fit=crop&dpr=1 754w, https://images.theconversation.com/files/572019/original/file-20240129-21-24vhfq.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=354&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/572019/original/file-20240129-21-24vhfq.gif?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=354&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Atmospheric rivers forming over the tropical Pacific Ocean head for the U.S. West Coast.</span>
<span class="attribution"><a class="source" href="https://www.nps.gov/articles/images/AR-animation.gif">NOAA</a></span>
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<p>The cause of AR families is an active area of research. Compared with single atmospheric river events, AR families tend to be associated with lower atmospheric pressure heights across the North Pacific, higher pressure heights over the subtropics, a stronger and more zonally elongated jet stream and warmer tropical air temperatures. </p>
<p>Large-scale weather patterns and climate phenomena such as the <a href="https://www.climate.gov/news-features/blogs/enso/what-mjo-and-why-do-we-care">Madden-Julian Oscillation</a>, or MJO, <a href="https://doi.org/10.1175/BAMS-D-22-0208.1">also play an important role</a> in the generation of AR families. An active MJO shift occurred during the early 2023 events, tilting the odds toward increased atmospheric river activity over California.</p>
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<img alt="A truck drives through muddy streets that fill a large section of town. People stand on one small patch of pavement not flooded." src="https://images.theconversation.com/files/572098/original/file-20240130-21-dc67s7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/572098/original/file-20240130-21-dc67s7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=336&fit=crop&dpr=1 600w, https://images.theconversation.com/files/572098/original/file-20240130-21-dc67s7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=336&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/572098/original/file-20240130-21-dc67s7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=336&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/572098/original/file-20240130-21-dc67s7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=423&fit=crop&dpr=1 754w, https://images.theconversation.com/files/572098/original/file-20240130-21-dc67s7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=423&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/572098/original/file-20240130-21-dc67s7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=423&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">An aerial view shows a flooded neighborhood in the community of Pajaro in central California on March 11, 2023, after a series of atmospheric rivers.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/an-aerial-view-shows-a-flooded-neighborhood-in-the-news-photo/1248039581">Josh Edelson/AFP via Getty Images</a></span>
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<p>A recent study by scientists at Stanford and the University of Florida found that storms within AR families <a href="https://www.science.org/doi/10.1126/sciadv.adi7905">cause three to four times more economic damage</a> when the storms arrive back to back than they would have caused by themselves.</p>
<h2>How important are atmospheric rivers to the West Coast’s water supply?</h2>
<p>I’m a research hydrologist, so I focus on hydrological impacts of atmospheric rivers. Although they can lead to flood hazards, atmospheric rivers are also essential to the Western water supply. Atmospheric rivers have been responsible for ending <a href="https://doi.org/10.1175/JHM-D-13-02.1">more than a third</a> of the region’s major droughts, including the severe California drought of 2012-16.</p>
<p>Atmospheric rivers provide an average of <a href="https://doi.org/10.1111/j.1752-1688.2011.00546.x">30% to 50% of the West Coast’s annual precipitation</a>. </p>
<p>They also contribute to the snowpack, which provides a significant portion of California’s year-round water supply. </p>
<p>In an average year, one to two extreme atmospheric rivers with snow will be the dominant contributors to the snowpack in the Sierra Nevada. Together, atmospheric rivers will <a href="https://doi.org/10.1029/2010GL044696">contribute about 30% to 40%</a> of an average season’s total snow accumulation there.</p>
<figure class="align-center ">
<img alt="A dam spillway with a full reservoir behind it." src="https://images.theconversation.com/files/572102/original/file-20240130-15-f4mjgk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/572102/original/file-20240130-15-f4mjgk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=382&fit=crop&dpr=1 600w, https://images.theconversation.com/files/572102/original/file-20240130-15-f4mjgk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=382&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/572102/original/file-20240130-15-f4mjgk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=382&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/572102/original/file-20240130-15-f4mjgk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=481&fit=crop&dpr=1 754w, https://images.theconversation.com/files/572102/original/file-20240130-15-f4mjgk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=481&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/572102/original/file-20240130-15-f4mjgk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=481&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">After several winter storms brought record snowfall to California’s Sierra Nevada in early 2023, Lake Oroville, California’s second-largest reservoir, was at 100% capacity. The previous year, much of the state had faced water restrictions.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/in-an-aerial-view-water-is-released-on-the-main-spillway-at-news-photo/1498829327">Justin Sullivan/Getty Images</a></span>
</figcaption>
</figure>
<p>That’s why my colleagues at the <a href="https://cw3e.ucsd.edu/">Center for Western Weather and Water Extremes</a> at the Scripps Institution of Oceanography, part of the University of California, San Diego, work on <a href="https://doi.org/10.1175/BAMS-D-22-0208.1">improving atmospheric river forecasts and predictions</a>. Water managers need to be able to regulate reservoirs and figure out how much water they can save for the dry season while still leaving room in the reservoirs to manage flood risk from future storms.</p>
<h2>How is global warming affecting atmospheric rivers?</h2>
<p>Warmer air can <a href="https://theconversation.com/climate-change-is-intensifying-the-water-cycle-bringing-more-powerful-storms-and-flooding-heres-what-the-science-shows-187951">hold more moisture</a>. As global temperatures rise in the future, we can expect more intense atmospheric rivers, leading to an <a href="https://doi.org/10.1038/s41598-019-46169-w">increase in heavy and extreme precipitation events</a>. </p>
<p>My research also shows that more atmospheric rivers are <a href="https://doi.org/10.1175/JHM-D-19-0242.1">likely to occur concurrently during already wet conditions</a>. So, the chance of extreme flooding also increases. Another study, by scientists from the University of Washington, suggests that there will be a <a href="https://doi.org/10.1175/JHM-D-16-0200.1">seasonal shift</a> to more atmospheric rivers earlier in the rainy season.</p>
<p>There will likely also be more <a href="https://doi.org/10.1038/s41598-019-46169-w">year-to-year variability</a> in the total annual precipitation, particularly in California, as a study by my colleagues at the Center for Western Weather and Water Extremes projects.</p>
<p><em>This article was update Feb. 5, 2024, with flooding and mudslides in California.</em></p><img src="https://counter.theconversation.com/content/222249/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Qian Cao does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>These giant rivers in the sky are both destructive and essential for the Western U.S. water supply.Qian Cao, Hydrologist, Center for Western Weather and Water Extremes, University of California, San DiegoLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2208162024-01-24T16:09:16Z2024-01-24T16:09:16ZHumans are depleting groundwater worldwide, but there are ways to replenish it<figure><img src="https://images.theconversation.com/files/570486/original/file-20240121-27-v80ph8.jpg?ixlib=rb-1.1.0&rect=0%2C24%2C5504%2C3495&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Circular irrigation for growing hay and alfalfa near Corcoran, Calif. − a water-intensive system that relies on groundwater pumping. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/circular-irrigation-system-for-growing-hay-and-alfalfa-is-news-photo/1482425392">George Rose/Getty Images</a></span></figcaption></figure><p>If you stand at <a href="https://pubs.usgs.gov/circ/circ1186/html/gen_facts.html">practically any point on Earth</a>, there is water moving through the ground beneath your feet. <a href="https://www.worldbank.org/en/topic/water/brief/understanding-the-value-of-groundwater-in-a-changing-climate">Groundwater provides</a> about half of the world’s population with drinking water and nearly half of all water used to irrigate crops. It sustains rivers, lakes and wetlands during droughts.</p>
<p>Groundwater is a renewable resource, but it can take <a href="https://pubs.usgs.gov/gip/gw/how_a.html">decades or even centuries</a> for some aquifers to recover after they are depleted. Current understanding of this challenge is based mainly on where and how frequently people record measurements of water levels in wells. </p>
<p>In a <a href="https://www.nature.com/articles/s41586-023-06879-8">newly published study</a>, our team of <a href="https://scholar.google.com/citations?user=9lzSDgcAAAAJ&hl=en">data scientists</a>, <a href="https://scholar.google.com/citations?user=43AJs30AAAAJ&hl=en">water specialists</a> and <a href="https://scholar.google.com/citations?user=BmbVaAgAAAAJ&hl=en">policy experts</a> compiled the first global-scale dataset of these levels. We analyzed millions of groundwater level measurements in 170,000 wells located in over 40 countries and mapped how groundwater levels have changed over time.</p>
<p>Our study has two main findings. First, we show that rapid groundwater depletion is widespread around the world and that rates of decline have accelerated in recent decades, with levels falling by 20 inches or more yearly in some locations. Second, however, our research also reveals many cases where deliberate actions halted groundwater depletion. These results show that societies are not inevitably doomed to drain their groundwater supplies, and that with timely interventions, this important resource can recover.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/H1OhKb3qEPA?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Communities in Bangkok, Tucson and Albuquerque have found ways to replenish their groundwater sources.</span></figcaption>
</figure>
<h2>Portrait of a thirsty planet</h2>
<p>Many factors determine groundwater levels, including geology, climate and land use. But groundwater levels that are dropping deeper and deeper in a particular location often signal that people are pumping it out faster than nature can replenish it.</p>
<p>Some of the 300 million measurements we compiled were recorded by automated measuring devices. Many others were made in the field by people around the globe. And these measurements paint a worrying picture.</p>
<p>They show that groundwater levels have declined since the year 2000 in far more places than they rose. In many locations, especially arid zones that are heavily farmed and irrigated, groundwater levels are falling by more than 20 inches (0.5 meters) per year. Examples include Afghanistan, Chile, China, Peninsular India, Iran, Mexico, Morocco, Saudi Arabia, Spain and the U.S. Southwest. </p>
<p>Our second and more concerning finding is that in about one-third of the areas where we compiled measurements, the rate of groundwater decline is accelerating. Accelerated groundwater decline is common in dry climates where large swaths of land are used for agriculture. This suggests a potential link between groundwater-fed irrigation and intensifying groundwater depletion.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/570487/original/file-20240121-29-uex7t1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Infographc showing various uses of groundwater." src="https://images.theconversation.com/files/570487/original/file-20240121-29-uex7t1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/570487/original/file-20240121-29-uex7t1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=872&fit=crop&dpr=1 600w, https://images.theconversation.com/files/570487/original/file-20240121-29-uex7t1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=872&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/570487/original/file-20240121-29-uex7t1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=872&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/570487/original/file-20240121-29-uex7t1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1096&fit=crop&dpr=1 754w, https://images.theconversation.com/files/570487/original/file-20240121-29-uex7t1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1096&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/570487/original/file-20240121-29-uex7t1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1096&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Groundwater is an essential but underappreciated resource worldwide.</span>
<span class="attribution"><a class="source" href="https://www.worldbank.org/en/news/infographic/2022/03/23/groundwater-vital-but-invisible">World Bank</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>What happens when groundwater is overused?</h2>
<p>Rapid and accelerating groundwater-level declines have many harmful effects.</p>
<p>Drinking-water supplies from wells and springs <a href="https://theconversation.com/water-wells-are-at-risk-of-going-dry-in-the-us-and-worldwide-160147">can run dry when groundwater levels decline</a>. People and communities who rely on those wells can lose access to what may be their sole source of accessible fresh water for drinking.</p>
<p>For example, wells that supply fresh water to homes are <a href="https://apnews.com/article/california-droughts-climate-and-environment-e49c8c5c34ead7ef7f83b770082f20bc">running dry in California’s San Joaquin Valley</a>, where <a href="https://doi.org/10.1038/s41467-022-35582-x">groundwater depletion has accelerated</a> since the early 2000s. This problem is likely to continue and worsen unless action is taken to stabilize groundwater reserves. </p>
<p>Wells that run dry can also <a href="http://dx.doi.org/%2010.1126/sciadv.abd284">threaten crop production</a>. Groundwater depletion has long been viewed as one of the <a href="https://wwnorton.co.uk/books/9780393319378-pillar-of-sand">greatest threats to global irrigated agriculture</a>, because wells supply nearly half of the water used for irrigation globally. </p>
<p>In areas where groundwater typically drains to rivers, <a href="https://doi.org/10.1029/2022WR032831">falling groundwater levels can reverse this flow</a> and cause rivers to leak into the subsurface. This affects the river’s ecology and <a href="https://doi.org/10.1038/s41586-019-1594-4">reduces water supplies downstream</a>. In the U.S., leaky streams are more common <a href="https://doi.org/10.1038/s41586-021-03311-x">where groundwater withdrawal rates are high</a>, highlighting how groundwater pumping can directly reduce the amount of water that flows underground into nearby rivers.</p>
<p>Groundwater declines can also cause land surfaces to sink. Land subsidence has increased flood risks in <a href="https://doi.org/10.1029/2022GL098477">dozens of coastal cities worldwide</a>, <a href="https://theconversation.com/sea-levels-are-rising-fastest-in-big-cities-heres-why-157077">including Jakarta, Tokyo</a>, <a href="https://doi.org/10.1029/2022GL098477">Istanbul, Mumbai, Auckland and the Tampa Bay area of Florida</a>. </p>
<p>Farther from the coast, land subsidence can damage infrastructure. It poses a critical challenge in areas where groundwater levels have declined, including <a href="https://www.tehrantimes.com/news/493254/Land-subsidence-in-Iran-five-times-global-average">Tehran</a> and <a href="https://eos.org/articles/groundwater-pumping-is-causing-mexico-city-to-sink">Mexico City</a>. In many cases, the main culprit is excessive groundwater pumping.</p>
<p><div data-react-class="InstagramEmbed" data-react-props="{"url":"https://www.instagram.com/p/CeEa_Q-MbOO/?utm_source=ig_web_copy_link\u0026igsh=MzRlODBiNWFlZA==","accessToken":"127105130696839|b4b75090c9688d81dfd245afe6052f20"}"></div></p>
<p>Finally, falling groundwater can cause seawater to move inland underground and contaminate coastal groundwater systems – a process known as <a href="https://theconversation.com/what-is-seawater-intrusion-a-hydrogeologist-explains-the-shifting-balance-between-fresh-and-salt-water-at-the-coast-214620">seawater intrusion</a>. When seawater intrudes, coastal aquifers can become too saline to use for drinking water without energy-intensive desalination.</p>
<h2>How to replenish groundwater supplies</h2>
<p>We also found places where groundwater levels are recovering. The strategies that communities used to replenish their groundwater sources included developing new alternative water supplies, such as local rivers; adopting policies to reduce demand for groundwater; and intentionally replenishing aquifers with surface water.</p>
<p>The town of El Dorado, Arkansas, saw its groundwater levels drop by roughly 200 feet (60 meters) from 1940 through 2000 as local industries pumped water from the aquifer. In 1999, a new policy established a pumping fee structure, giving businesses an incentive to find a new water supply. By 2005, a pipeline had been built to <a href="https://pubs.usgs.gov/fs/2007/3102/">divert water from the Ouachita River to El Dorado</a>. This new source reduced demand for groundwater, and groundwater levels have risen in the area since 2005.</p>
<p>In Bangkok, so many private wells were drilled <a href="https://www.un-igrac.org/resource/thailand-controlling-gw-abstraction-and-related-environmental-degradation-metropolitan">for domestic, industrial or commercial purposes</a> between 1980 and 2000 that <a href="https://www.un-igrac.org/resource/thailand-controlling-gw-abstraction-and-related-environmental-degradation-metropolitan">groundwater pumping doubled</a> and groundwater levels fell. Officials responded by <a href="https://link.springer.com/chapter/10.1007/978-4-431-53904-9_14">quadrupling groundwater extraction fees between 2000 and 2006</a>. Total groundwater pumping declined, and levels began to recover as users found other water sources.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/0HPrKqRBhS4?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">In wet years, water managers in Fresno, Calif., pump water out of rivers and canals into recharge basins. There, the water can sink slowly into the ground and recharge groundwater supplies.</span></figcaption>
</figure>
<p>In a valley near Tucson, Arizona, groundwater levels declined by 100 feet (30 meters) as withdrawals for irrigation increased after the 1940s. To help replenish the depleted groundwater, <a href="https://pubs.usgs.gov/publication/sir20185154">leaky ponds were constructed</a>. These ponds are filled with water from the Colorado River that is moved hundreds of miles to the area via canals. As these ponds leak, they refill the depleted aquifer. Because of these leaky ponds, groundwater levels in the valley have risen by about 200 feet (60 meters) in places.</p>
<p>Our analysis shows how important it is to monitor groundwater levels in many locations. With groundwater levels declining in many places, communities and businesses that depend on it need accurate information about their water supplies so they can act in time to protect them.</p><img src="https://counter.theconversation.com/content/220816/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Scott Jasechko receives funding from the National Science Foundation and the Zegar Family Foundation. This material is based upon work supported by the U.S. Geological Survey through the California Institute for Water Resources . The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the opinions or policies of USGS/CIWR. Mention of trade names or commercial products does not constitute their endorsement by USGS/CIWR. </span></em></p><p class="fine-print"><em><span>Debra Perrone receives funding from the National Science Foundation. </span></em></p><p class="fine-print"><em><span>Richard Taylor receives funding from the Canadian Institute For Advanced Research through a Fellowship under the Earth 4D: Subsurface Science and Exploration Program. He is also supported by a research grant from the UK Government’s Foreign, Commonwealth & Development Office and the International Development Research Centre, Ottawa, Canada. </span></em></p>Rapid and accelerating groundwater level declines are widespread in dry climates where groundwater is used for irrigation. But some communities have found ways to turn things around.Scott Jasechko, Associate Professor of Water Resources, University of California, Santa BarbaraDebra Perrone, Associate Professor of Environmental Studies, University of California, Santa BarbaraRichard Taylor, Professor of Hydrogeology, UCLLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2173522023-12-21T19:26:32Z2023-12-21T19:26:32ZIndia’s new manual for water supply will replicate past failures<iframe style="width: 100%; height: 100px; border: none; position: relative; z-index: 1;" allowtransparency="" allow="clipboard-read; clipboard-write" src="https://narrations.ad-auris.com/widget/the-conversation-canada/indias-new-manual-for-water-supply-will-replicate-past-failures" width="100%" height="400"></iframe>
<p>Water utilities in India supply residents with water for an average of <a href="https://doi.org/10.1016/j.cesys.2021.100062">only four hours per day</a>. Within cities, some neighbourhoods receive water almost all the time, while some receive <a href="https://doi.org/10.1016/j.scitotenv.2023.164393">less than half an hour per week</a>. </p>
<p>Intermittent supply of water <a href="https://doi.org/10.1002/2016WR019702">inconveniences everyone</a> and often disproportionately <a href="https://doi.org/10.1111/j.1548-1360.2011.01111.x">burdens the poorest and most vulnerable</a>. Yet intermittent water supply has been the norm <a href="https://books.google.com/books?id=e8AIAAAAQAAJ&pg=230">in India since at least 1873</a>. </p>
<p>Our research at the University of Toronto studies <a href="https://www.geography.utoronto.ca/people/directories/all-faculty/nidhi-subramanyam">the social</a> <a href="https://civmin.utoronto.ca/home/about-us/directory/professors/david-meyer/">and technical</a> causes and effects of intermittent supply in India.</p>
<h2>Perpetuating past problems</h2>
<p>Over the last few years, the Indian government <a href="https://pib.gov.in/Pressreleaseshare.aspx?PRID=1811880">has launched several</a> <a href="https://jaljeevanmission.gov.in/">initiatives to improve water supply systems</a> and reduce intermittent supply. <a href="https://doi.org/10.1021/acs.est.5b03973">Continuous water supply</a> keeps contaminants out of the pipes and lets users drink from the tap at any time.</p>
<p>In support of these new initiatives, India’s Central Public Health and Environmental Engineering Organisation <a href="https://pib.gov.in/PressReleasePage.aspx?PRID=1933379">issued a new draft of the Manual on Water Supply and Treatment</a>, its first update since 1999. </p>
<p>This manual was prepared in collaboration with the <a href="https://www.giz.de/en/html/about_giz.html">German Development Agency (GIZ</a>), and workshopped over the summer at a national conference organized by the national Ministry of Housing and Urban Affairs. The conference was attended by water supply engineers, experts, and consultants from cities across India. </p>
<p>As in the <a href="https://www.mdws.gov.in/sites/default/files/Manual_on_Water_Supply_and_Treatment_CPHEEO_MoUD_1999.pdf">previous version</a>, the 2023 manual boldly aims to establish continuous piped water supply — a goal that still has not been achieved, nearly 25 years later. This piped water is intended primarily for indoor residential use. </p>
<p>We believe that this new continuous supply target is also unlikely to be reached due to two fatal flaws that are baked into the plan from the start. While continuous supply requires both a realistic projection of water demand and a realistic plan to ensure supply exceeds demand, the government of India’s new initiatives are unrealistic on both fronts. </p>
<h2>Underestimated demand</h2>
<p>First, the manual dramatically underestimates demand, the volume of water people will try to withdraw; true demand is more than double the projections <a href="https://doi.org/10.1029/2018WR024124">in some locations</a>. For a system to operate continuously, the water withdrawn from the system must remain well below the maximum amount that can be conveyed from its source — if not, <a href="https://doi.org/10.1029/2018WR024124">the system will become intermittent</a>. </p>
<p>The new manual estimates the amount of water demand based on the projected number of users multiplied by the estimated amount that each person will withdraw in a day. However, these estimates are based upon 1999 figures for the minimum requirements for drinking, cooking, and bathing: <a href="https://www.mdws.gov.in/sites/default/files/Manual_on_Water_Supply_and_Treatment_CPHEEO_MoUD_1999.pdf">135 litres per person in most cities (150 in the country’s biggest cities</a>). </p>
<p>These estimates are reasonable projections of the minimum amount of water urbanites <em>need</em> but they grossly underestimate how much water urbanites <em>want</em>. Most users attempt to <a href="https://doi.org/10.1029/2018WR024124">withdraw the water they want</a>, rather than what they need. </p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/india-why-collecting-water-turns-millions-of-women-into-second-class-citizens-104698">India: why collecting water turns millions of women into second-class citizens</a>
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<p>The manual could and should be informed by data about user withdrawals from the last 24 years. The manual’s prescriptions for <a href="https://doi.org/10.2166/aqua.2022.149">calculating water demand should also consider the water wants of low-income populations in informal settlements and seasonal, interstate migrant workers</a>.</p>
<p>Second, the manual’s authors assume that water tariffs will be set high enough to limit users to withdrawing only the water they need. But demand-limiting tariffs have never been realized in India. </p>
<p>Sustaining high tariffs is particularly challenging as Indian politicians like Delhi’s Chief Minister Arvind Kejriwal may use <a href="https://timesofindia.indiatimes.com/city/delhi/24x7-water-supply-for-all-of-delhi-soon/articleshow/103878291.cms">free-water services</a> or lower tariffs as tools to earn voters’ approval.</p>
<p>Consider, for example, water tariffs in Bengaluru, which are higher than many cities. A family of four consuming the guideline-anticipated 150 litres per person per day will be billed Rupees <a href="https://bwssb.karnataka.gov.in/new-page/Prorata%20and%20Water%20Tariff/en">8.6 per day</a> (CAD$0.14/day); if they consume 30 per cent more than expected, their water tariffs increase by only Rupees 2.7 per day (less than $0.05/day). </p>
<p>Bengaluru’s elite will not limit their consumption for Rs 3 (five cents) — which is less than the price of a cup of tea! </p>
<p>If the manual’s anticipated high tariffs strategy for limiting demand fails, then users will withdraw more water than expected. When these higher-than-expected withdrawals exceed the system capacity, the system will become intermittent again. </p>
<p>Tragically, the drawbacks of intermittent supply will be magnified in these systems since the manual recommends they be designed as if continuous operation was guaranteed. </p>
<h2>Supply and demand</h2>
<p>Water system engineers in India are faced with two irreconcilable options: design water systems that meet only users’ minimum needs and accept intermittent operations, or design systems to sustain continuous supply by providing as much water as users want. </p>
<p>The long history of intermittent supply in India suggests that water systems designed using need-based demands are fragile and almost always revert to intermittent operations. </p>
<p>If India’s future systems are built according to the new manual — focused on providing users’ minimum needs — these new systems will never operate continuously. When these systems inevitably become intermittent, they will operate less fairly, less efficiently and less safely than if they had been designed to operate intermittently from the outset.</p>
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<strong>
Read more:
<a href="https://theconversation.com/how-indias-civil-society-can-shape-the-countrys-water-policy-144860">How India's civil society can shape the country's water policy</a>
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<p>The new manual’s aim for continuous supply replicates the failures of its predecessor and perpetuates decades of self-defeating water supply projects. </p>
<p>It’s a missed opportunity to design water systems that will operate well under both continuous and intermittent modes which are resilient to problematic demand projections, ineffective demand management, and water supply scarcity.</p><img src="https://counter.theconversation.com/content/217352/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>David Meyer receives funding from the Natural Sciences and Engineering Research Council of Canada and has previously received in-kind support from several public and private water utilities in India.</span></em></p><p class="fine-print"><em><span>Nidhi Subramanyam has previously received funding from the Social Sciences and Humanities Research Council of Canada and the International Development Research Centre in Ottawa. She has also been involved in projects supporting a private water utility in India.</span></em></p>Achieving continuous supply requires both a realistic assessment of the situation and a realistic plan to meet the goal. The Government of India’s new initiatives have neither.David Meyer, Assistant Professor in Civil and Global Engineering, University of TorontoNidhi Subramanyam, Assistant Professor of Geography and Planning, University of TorontoLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2163632023-12-13T00:57:15Z2023-12-13T00:57:15ZOur cities will need to harvest stormwater in an affordable and green way – here’s how<figure><img src="https://images.theconversation.com/files/564125/original/file-20231207-23-7hui6e.jpg?ixlib=rb-1.1.0&rect=0%2C8%2C5991%2C3979&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/drive-during-rainy-season-passing-through-1229404258">koifish/Shutterstock</a></span></figcaption></figure><p>When it rains, stormwater runs down surfaces like streets and parking lots and into drains. Most of the time, we see it as a problem because it can cause floods. <a href="https://www.abc.net.au/news/2023-11-29/major-weather-hits-queensland-nsw-victoria-storms-coming/103166982">Recent storms</a> across eastern Australia created huge amounts of stormwater and flooding.</p>
<p>At such times, stormwater is seen as a problem. But it’s also the last untapped source of <a href="http://www.bom.gov.au/water/nwa/2022/urban/">water available for cities</a>.</p>
<p>We all know how important it is to have enough water for our needs. But did you know our growing cities might struggle to get enough clean water in future? </p>
<p>Stormwater is a hidden treasure, and we’re not making the most of it.</p>
<figure class="align-center ">
<img alt="Rain water flows down a street drain" src="https://images.theconversation.com/files/564126/original/file-20231207-29-63vsqc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/564126/original/file-20231207-29-63vsqc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/564126/original/file-20231207-29-63vsqc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/564126/original/file-20231207-29-63vsqc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/564126/original/file-20231207-29-63vsqc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/564126/original/file-20231207-29-63vsqc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/564126/original/file-20231207-29-63vsqc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Water down the drain is a wasted resource.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/rain-flowing-into-storm-water-sewer-1103174282">serato/Shutterstock</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-dams-are-full-for-now-but-sydney-will-need-new-water-supplies-as-rainfall-becomes-less-reliable-214071">The dams are full for now – but Sydney will need new water supplies as rainfall becomes less reliable</a>
</strong>
</em>
</p>
<hr>
<h2>Why do we need to tap stormwater?</h2>
<p>More people are moving to cities in <a href="https://soe.dcceew.gov.au/urban/pressures/population">Australia</a> and <a href="https://www.un.org/development/desa/pd/content/urbanization-0">worldwide</a>. They all need clean water. <a href="https://population.un.org/wup/">By 2050</a>, 30 million of Australia’s population and 6.6 billion globally will live in urban areas. </p>
<p>But climate change and population growth are <a href="https://www.sciencedirect.com/science/article/pii/S0959652620313779">making it harder</a> for cities to meet the demand for clean water. </p>
<p>In coming years, Australia’s weather will <a href="https://www.science.org.au/curious/policy-features/whats-happening-australias-rainfall">be a bit strange</a>. We’ll have longer dry periods with brief periods of intense rainfall. It’s like the weather is playing a game of “now you see it, now you don’t” – and it will test our capacity to supply enough clean water for everyone.</p>
<p>To make matters worse, current solutions such as desalination and treating wastewater are <a href="https://www.unep.org/news-and-stories/story/five-things-know-about-desalination">very expensive, energy-intensive and are not the greenest options</a>.</p>
<p>Researchers have found a way to collect and clean stormwater without damaging our natural environment or our wallets. They call it “<a href="https://www.undp.org/publications/nature-based-solutions-water">nature-based solutions</a>”. It’s like giving stormwater a makeover. </p>
<p>This approach can not only <a href="https://pubs.acs.org/doi/10.1021/acs.est.8b05913">give us more clean water</a> but also helps stop pollution and flooding. It’s a win for everyone.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/desalinating-seawater-sounds-easy-but-there-are-cheaper-and-more-sustainable-ways-to-meet-peoples-water-needs-184919">Desalinating seawater sounds easy, but there are cheaper and more sustainable ways to meet people's water needs</a>
</strong>
</em>
</p>
<hr>
<figure class="align-center ">
<img alt="Aerial view of lake in front of skycrapers in Melbourne CBD" src="https://images.theconversation.com/files/564135/original/file-20231207-23-tofekf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/564135/original/file-20231207-23-tofekf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=306&fit=crop&dpr=1 600w, https://images.theconversation.com/files/564135/original/file-20231207-23-tofekf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=306&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/564135/original/file-20231207-23-tofekf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=306&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/564135/original/file-20231207-23-tofekf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=384&fit=crop&dpr=1 754w, https://images.theconversation.com/files/564135/original/file-20231207-23-tofekf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=384&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/564135/original/file-20231207-23-tofekf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=384&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Urban planning needs to include more water-sensitive infrastructure to capture and treat stormwater.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/melbourne-australia-aerial-city-skyline-helicopter-2238267873">GagliardiPhotography/Shutterstock</a></span>
</figcaption>
</figure>
<h2>A lot of water and money at stake</h2>
<p>Back in 2015, an Australian Senate <a href="https://www.aph.gov.au/parliamentary_business/committees/senate/environment_and_communications/stormwater/report">report</a> said we should do more research to manage stormwater better.</p>
<p>One reason is that water clean-up is expensive. Australia spends around <a href="https://www.trade.gov/country-commercial-guides/australia-water-and-wastewater-treatment">A$9 billion</a> a year on water and wastewater treatment.</p>
<p>Another reason is the waste of water. We let <a href="https://www.aph.gov.au/parliamentary_business/committees/senate/environment_and_communications/stormwater/report">3,000 billion litres</a> – that’s a lot of water – of urban stormwater go into rivers and seas without cleaning it. This not only damages our water ecosystems but is throwing away a <a href="https://pubs.acs.org/doi/10.1021/acs.est.8b05913">potentially precious resource</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/when-water-is-scarce-we-cant-afford-to-neglect-the-alternatives-to-desalination-111249">When water is scarce, we can't afford to neglect the alternatives to desalination</a>
</strong>
</em>
</p>
<hr>
<h2>Learning from nature</h2>
<p>Nature-based solutions are nature-inspired, engineered systems for tackling water issues in cities. </p>
<p>Natural wetlands, for instance, can hold huge amounts of water, release it slowly, prevent flooding and even make the water cleaner as it works its way through soil and plants. Now cities like <a href="https://urbanwater.melbourne.vic.gov.au/projects/wetlands/wetlands-sample-project/">Melbourne</a> in Australia, <a href="https://theconversation.com/creating-sponge-cities-to-cope-with-more-rainfall-neednt-cost-billions-but-nz-has-to-start-now-211181">Auckland</a> in New Zealand and so-called “<a href="https://www.dw.com/en/china-turns-cities-into-sponges-to-stop-flooding/a-61414704">sponge cities</a>” in China have adopted this idea by constructing wetlands in urban areas.</p>
<p>Diving further into how these nature-based solutions can solve <a href="https://www.sciencedirect.com/science/article/pii/S0022169418308278">stormwater problems</a>, we’re also talking about green walls, bioswales (fancy ditches with plants), green roofs and permeable pavements. </p>
<p>And there’s a star among them – biofiltration systems. Biofilters clean polluted waters by passing it through soil, with plants and microorganisms helping to remove pollutants. </p>
<p>These systems are like water-treatment wizards. They can handle polluted waters in different situations, from regular stormwater to intermittent stormwater and wastewater, even when big storms produce a challenging mix of sewage and stormwater.</p>
<p>Nature-based systems can be designed to clean stormwater and meet various water quality standards. This means we can treat stormwater to meet the strictest standards, like those needed for drinking water (though more work is needed to reach that ambitious goal). Or we can treat it to meet lower standards suitable for other uses such as watering lawns and sports grounds. </p>
<p>In any case, treated stormwater can be safely released into receiving waters without significant risks to aquatic environments.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/creating-sponge-cities-to-cope-with-more-rainfall-neednt-cost-billions-but-nz-has-to-start-now-211181">Creating ‘sponge cities’ to cope with more rainfall needn't cost billions – but NZ has to start now</a>
</strong>
</em>
</p>
<hr>
<h2>What challenges remain?</h2>
<p>There are still some challenges to overcome. </p>
<p>One big challenge involves figuring out how polluted stormwater is. We’re getting better with sensors that can check <a href="https://www.mdpi.com/1424-8220/21/9/3056">water depth and electrical conductivity</a> in stormwater. These help us understand the amount of stormwater we have and get a rough idea of the pollution level. </p>
<p>However, we need to make these sensors even better to detect and measure toxic pollutants such as heavy metals and hydrocarbons, which are commonly found in stormwater. This will help us design treatment systems that really work.</p>
<p>Cleaning stormwater using nature-based methods is good, but some specific pollutants aren’t removed fully. We can make these methods better by changing how we design them. For example, we can improve how we filter pollutants and find better plants and microbes that can absorb and remove more toxic substances from the water.</p>
<p>Besides the usual pollutant removal methods, there are some promising ideas like the <a href="https://www.sciencedirect.com/topics/chemical-engineering/anaerobic-ammonium-oxidation#:%7E:text=Anammox%20is%20a%20chemoautotrophic%20biological,et%20al.%2C%202018">Anammox process</a> – short for anaerobic ammonium oxidation – which relies on bacteria to help get rid of nitrogen. We need to figure out how to use these bacteria in nature-based stormwater treatment systems.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/stormwater-innovations-mean-cities-dont-just-flush-rainwater-down-the-drain-40129">Stormwater innovations mean cities don't just flush rainwater down the drain</a>
</strong>
</em>
</p>
<hr>
<p>We also need to know more about how pollution works. The existing tools (mathematical models) aren’t perfect. Modelling tools must be developed so they can consider all the different sources of pollution, estimate how bad it is, and deal with its unpredictability. This will help us use stormwater better, especially with cities growing fast and weird weather happening.</p>
<p>Finally, and perhaps most importantly, governments and people need to understand that providing clean water for everyone <a href="https://www.un.org/sustainabledevelopment/water-and-sanitation">is essential</a>. But progress is slow, and one reason is we’re not putting enough effort into using stormwater as a solution. Governments need to invest in research and convince the public it’s a smart move.</p><img src="https://counter.theconversation.com/content/216363/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Buddhi Wijesiri has received funding from Queensland Urban Utilities.</span></em></p>Too much stormwater is disappearing down the drain. Here’s how our cities can make more of their last untapped water source.Buddhi Wijesiri, Research Associate in Water and Environmental Engineering, Queensland University of TechnologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2140712023-10-19T19:03:31Z2023-10-19T19:03:31ZThe dams are full for now – but Sydney will need new water supplies as rainfall becomes less reliable<figure><img src="https://images.theconversation.com/files/554636/original/file-20231018-25-7qn0od.jpg?ixlib=rb-1.1.0&rect=58%2C25%2C5555%2C3720&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>When Australia last went into El Niño, we had water supply issues in Brisbane, Sydney, Canberra and Melbourne.</p>
<p>Are we better placed now, after three wet La Niña years? Yes and no. Take Sydney as an example. After the big wet, Greater Sydney’s dams are <a href="https://waterinsights.waternsw.com.au/12964-sydney-drinking-water-catchment/storage">around 90% full</a>, holding more than four times the volume we use in a year. But hot, dry weather can drain them surprisingly rapidly through increased demand, increased evaporation and environmental flows in rivers such as the Nepean.</p>
<p>Hot weather also dries out the soil in water catchments. When it rains, dry soils soak up water like a sponge, preventing it from running off to waterways. This means there’s little runoff to replenish the dams. You need very intense rainfall to overcome this. </p>
<p>So despite Sydney’s full dams, it will inevitably face water supply shortages if El Niño returns for several years. That’s because the city of five million is highly dependent on rainfall, which isn’t always plentiful and doesn’t always produce runoff. </p>
<p>To fix this problem and future-proof supplies as climate change makes rainfall less reliable, we must draw more water from desalination plants and recycling schemes. </p>
<h2>Desalination</h2>
<p>The combined effects of a growing population and future periods of drought will increasingly challenge our ability to meet water demand from Sydney’s dams.</p>
<p>In 2010, Sydney’s first <a href="https://sydneydesal.com.au">large seawater desalination plant</a> came on line. At maximum production, it can provide 90 gigalitres of drinking water per year. This is about 15% of Sydney’s annual demand. </p>
<p>In the past, the desal plant has been turned off and on depending on rainfall. After the Millennium Drought broke in 2009, dams began refilling. Once Sydney’s dams were 90% full in 2012, the plant was switched off. In 2019, it was turned back on as drought intensified. One problem is that it takes months to restart a mothballed desalination plant. </p>
<p>If the desalination plant had been operating continuously at a low rate, it could have more quickly shored up supply shortages when the drought started in 2017.</p>
<p>To achieve full benefit, desal plants must be used to provide ongoing service, rather than just as an emergency drought-response solution. Keeping the plant running is also an effective way of maintaining the workforce and skills required to operate the plant when it’s needed.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/554676/original/file-20231019-29-pyeh6o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="room full of reverse osmosis tubes in a desalination plant" src="https://images.theconversation.com/files/554676/original/file-20231019-29-pyeh6o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/554676/original/file-20231019-29-pyeh6o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=427&fit=crop&dpr=1 600w, https://images.theconversation.com/files/554676/original/file-20231019-29-pyeh6o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=427&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/554676/original/file-20231019-29-pyeh6o.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=427&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/554676/original/file-20231019-29-pyeh6o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=537&fit=crop&dpr=1 754w, https://images.theconversation.com/files/554676/original/file-20231019-29-pyeh6o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=537&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/554676/original/file-20231019-29-pyeh6o.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=537&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Desalination plants often rely on reverse osmosis to remove the salt and other impurities from seawater.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Water recycling</h2>
<p>Many cities around Australia now have desal plants. Fewer have explored <a href="https://www.seqwater.com.au/purified-recycled-water">purified water recycling</a> from wastewater treatment plants due to unwarranted public scepticism. </p>
<p>Australia’s most significant purified recycled water project is Perth’s <a href="https://www.watercorporation.com.au/Our-water/Groundwater/Groundwater-replenishment">groundwater replenishment scheme</a>, built to refill the aquifers on which the city draws much of its water. </p>
<p>Beginning in 2017, wastewater was purified and injected below ground into an important aquifer used for drinking water. The project was recently doubled in size, and now puts around 10% of Perth’s drinking water demand (28 gigalitres) back below ground annually.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-drought-is-affecting-water-supply-in-australias-capital-cities-127909">How drought is affecting water supply in Australia’s capital cities</a>
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<p>By 2035, <a href="https://www.watercorporation.com.au/About-us/Media-releases/2022/August-2022/Stage-Two-Groundwater-Replenishment-Scheme">Water Corporation aims</a> to recycle more than a third (35%) of treated wastewater. </p>
<p>Queensland has built but not fully used a far larger water recycling scheme, the Western Corridor Recycled Water Scheme. If it was used for drinking water as well as industrial use, it could add 80 GL a year to supply – more than a quarter of the water used by South East Queensland’s 3.8 million residents. That would be enough to <a href="https://www.seqwater.com.au/water-security">replenish supplies</a> in the region’s largest surface water storage, Lake Wivenhoe. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/554633/original/file-20231018-17-hr0obp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Fountain in Kings Park Perth, green grass" src="https://images.theconversation.com/files/554633/original/file-20231018-17-hr0obp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/554633/original/file-20231018-17-hr0obp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/554633/original/file-20231018-17-hr0obp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/554633/original/file-20231018-17-hr0obp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/554633/original/file-20231018-17-hr0obp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/554633/original/file-20231018-17-hr0obp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/554633/original/file-20231018-17-hr0obp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Perth has had to shift from dams to groundwater to desalination and water recycling as climate change makes rainfall less reliable.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>So what should Sydney do?</h2>
<p>Sydney relies on rainfall-dependent sources for about 80% of its drinking water supply.</p>
<p>If dry conditions continue, the city could be running short of water within three years, according to the <a href="https://water.dpie.nsw.gov.au/plans-and-programs/greater-sydney-water-strategy">Greater Sydney Water Strategy</a>. </p>
<p>To make sure that shortfall never arrives, Sydney needs to start building more rainfall-independent water supplies. This would help ensure full dams at the start of future droughts, allow more time to respond, and slow dam depletion rates during the drought. </p>
<p>Authorities could expand the desal plant. They could build a new desal plant. Or they could develop purified recycled water as an option. Each of these has costs and benefits which must be considered. </p>
<p>In reality, the city is likely to need all of the above. This is because there are limits to how much water can be delivered to any specific location in the supply network, so several water sources will be needed in different areas of Sydney.</p>
<p>The real question isn’t which one to choose. It’s which order to construct them in. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/sydneys-dams-may-be-almost-full-but-dont-relax-because-drought-will-come-again-170523">Sydney's dams may be almost full – but don't relax, because drought will come again</a>
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</p>
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<img src="https://counter.theconversation.com/content/214071/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Stuart Khan was a member of the Independent Metropolitan Water Advisory Panel appointed by previous NSW Minister for Water, Melinda Pavey MP to advise on the development and implementation of water plans for the Lower Hunter and Greater Sydney regions (2021-2023). He has previously received funding from Sydney Water. He is affiliated with the Australian Academy of Technology and Engineering.</span></em></p>To build drought resilence, Sydney must invest in rainfall-independent water supplies.Stuart Khan, Professor of Civil & Environmental Engineering, UNSW SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2085222023-07-17T15:05:48Z2023-07-17T15:05:48ZTechnology can boost farming in Africa, but it can also threaten biodiversity - how to balance the two<figure><img src="https://images.theconversation.com/files/535772/original/file-20230705-24-p5ks5m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Agriculture is a leading employer in Africa.</span> <span class="attribution"><span class="source">Wikimedia Commons</span></span></figcaption></figure><p>Cultivating one hectare of maize used to be an arduous task for Precious Banda, a farmer in Zambia. It would take her hundreds of hours to prepare her land before sowing and to keep it weed-free until harvest – equipped with nothing but a small hoe. She says it was backbreaking work: “I can still feel it.” For a few years now she has hired a tractor, and a neighbour sprays herbicides for her. “Life has become so easy,” she says. </p>
<p>But she has also noticed changes around her farm. There are fewer bees and – most worrying for her – fewer caterpillars, which used to make a delightful dish. </p>
<p>Precious Banda’s story is a perfect example of the situation millions of African farmers face. </p>
<p>Agricultural development is high on the policy agenda of African countries, as seen in the <a href="https://au.int/en/agenda2063/overview">Agenda 2063 of the African Union</a>. But while it’s needed to reduce poverty and hunger, agricultural development often clashes with biodiversity, <a href="https://www.wwf.de/living-planet-report/?gclid=EAIaIQobChMIy7Cvs633_wIVyzUGAB1muwNGEAAYASAAEgKt0vD_BwE">which is declining at an alarming rate</a>. Losing biodiversity could reduce food security by undermining ecosystem services like pollination, nutrient cycling and maintenance of water supplies. Wild food sources could also be lost. </p>
<p>In <a href="https://www.sciencedirect.com/science/article/pii/S0006320723002665">a new paper</a>, we as researchers in economics, agronomy and ecology emphasise the importance of biodiversity-smart agricultural strategies. With Precious Banda’s story in our minds, we argue that such strategies need to pay much more attention to agricultural labour dynamics. </p>
<h2>Biodiversity and agricultural labour</h2>
<p>Biodiversity is lost when agricultural land expands and when farming is more intense. In Africa, <a href="https://www.science.org/doi/full/10.1126/science.abf5413">75%</a> of agricultural growth comes from farmland expansion into forests and savannas. This leads to habitat loss and fragmentation. Farming more intensely curtails expansion, but may make the landscape less biodiverse and often leads to the use of more chemicals such as pesticides. </p>
<p>The importance of biodiversity-friendly agriculture is starting to be recognised more widely. But efforts to encourage it often neglect trade-offs with farm labour needs. We argue that neglecting these needs will undermine the success of biodiversity conservation efforts. </p>
<p>Farmers can reduce heavy labour by adopting technologies such as <a href="https://link.springer.com/article/10.1007/s13593-023-00868-x">mechanisation</a> and <a href="https://link.springer.com/article/10.1057/s41287-017-0090-7">herbicides</a>. For example, our <a href="https://www.sciencedirect.com/science/article/pii/S0306919218303816?via%3Dihub">previous research in Zambia</a> showed tractors cut land preparation time from 226 to 10 hours per hectare. And in Burkina Faso, herbicides are referred to as <a href="https://www.taylorfrancis.com/chapters/edit/10.4324/9781003110095-11/mother-little-helper-william-moseley-eliza-pessereau">“mothers’ little helpers”</a> because they reduce women’s work in the fields.</p>
<p>But labour-saving technologies can negatively affect biodiversity through farmland expansion, farmland simplification, land degradation and spillover effects. For example, <a href="https://link.springer.com/article/10.1007/s13593-020-00651-2">in an earlier study</a> in Benin, Kenya, Nigeria, and Mali, we found that mechanisation sometimes led to the removal of trees and hedges from farms, and changed plot sizes and shapes. This resulted in a loss of farm diversity and of a healthy “patchwork” of habitats. Pesticides can harm soil life, water systems and insect populations if badly regulated and managed, <a href="https://link.springer.com/article/10.1057/s41287-017-0090-7">as is often the case</a>. </p>
<p>Biodiversity-enhancing technologies have the opposite problem: farmers often don’t adopt them because they add to the labour burden. Examples include inter-cropping (growing different crops close to each other) and planting basins (shallow indentations in the soil to provide a suitable environment for crops and place inputs). In Zimbabwe, a <a href="https://www.sciencedirect.com/science/article/pii/S0378429014002846#sec0095">study</a> noted that planting basins could be labour-intensive without always increasing yields. </p>
<p>Farmers typically adopt technologies and practices that use the least labour and provide high and stable yields, but those can be bad for biodiversity conservation. </p>
<p>What’s needed instead are biodiversity-smart technologies that enable farming with low labour, high yields and high biodiversity. </p>
<h2>Biodiversity-smart agriculture</h2>
<p>One potential solution is to adapt machines to farm size – and not the other way around. Smaller machinery can easily manoeuvre around trees, hedges and other landscape features that are key for biodiversity. </p>
<p>Combining smart biological solutions (like crop rotation) and mechanical ones (like precision spraying) is a path to lower pesticide use. In our paper, we discuss many other options, too. </p>
<p>For example, in plantation agriculture, <a href="https://www.nature.com/articles/s41586-023-06086-5">tree-islands</a> can improve biodiversity without reducing yields, as shown in a recent study. </p>
<p>Biodiversity-smart technologies reduce the costs (in terms of yield and labour) of biodiversity conservation for individual farmers. That increases the likelihood of adoption. Where conservation comes with higher costs than benefits, financial compensation may also be needed. This could, for example, be in the form of certification schemes or payment for ecosystem services.</p>
<p>Farm-level solutions have to be accompanied by efforts at the landscape level. These might be careful land-use planning and monitoring to preserve biodiversity hotspots and keep habitats connected. Our case study from Ethiopia shows that multi-functional landscapes can be planned to <a href="https://www.science.org/doi/full/10.1126/science.aau6020">“work for biodiversity and people”</a>. </p>
<p>We argue that biodiversity-smart agricultural development requires a shift in both policy making and research and development. Conservation ecologists must pay more attention to economic and social sustainability. Without accounting for labour issues, conservation efforts are unlikely to succeed. At the same time, agricultural scientists have to embrace multiple goals beyond yields. </p>
<p>Our paper shows that technological, agronomic and institutional innovations for biodiversity-smart agriculture exist. But more needs to be done to scale them. If successful, they can help to feed the growing population, improve the livelihoods of farmers, and conserve biodiversity before it is too late.</p><img src="https://counter.theconversation.com/content/208522/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Thomas Daum receives funding from the German Federal Ministry for Economic Cooperation and Development (BMZ). </span></em></p><p class="fine-print"><em><span>Ingo Grass receives funding from the German Research Foundation (DFG) and the German Federal Ministry of Education and Research (BMBF). </span></em></p><p class="fine-print"><em><span>Matin Qaim receives funding from the German Research Foundation (DFG). </span></em></p><p class="fine-print"><em><span>Regina Birner receives funding from the German Federal Ministry for Economic Cooperation and Development (BMZ) and the German Academic Exchange Service (DAAD). She is a member of the Social Democratic Party of Germany (SPD).</span></em></p><p class="fine-print"><em><span>Frédéric Baudron does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Labour, yields, and biodiversity are all elements of agriculture that need to be balanced.Thomas Daum, Senior Research Fellow, University of HohenheimFrédéric Baudron, Systems Agronomist, International Maize and Wheat Improvement Center (CIMMYT)Ingo Grass, Professor, Department of Ecology of Tropical Agricultural Systems, University of HohenheimMatin Qaim, Director, Center for Development Research (ZEF), University of BonnRegina Birner, University of HohenheimLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2087512023-07-05T04:32:03Z2023-07-05T04:32:03ZDecades of less rainfall have cut replenishing of groundwater to 800-year low in WA<figure><img src="https://images.theconversation.com/files/534979/original/file-20230630-15-y2xpsk.jpg?ixlib=rb-1.1.0&rect=82%2C3%2C1235%2C818&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Lake Cave, Margaret River</span> <span class="attribution"><span class="source">Adobe Stock</span></span></figcaption></figure><p>Groundwater is the <a href="https://theconversation.com/the-worlds-biggest-source-of-freshwater-is-beneath-your-feet-53874">world’s biggest source</a> of easily accessible freshwater. Despite its importance, we know very little about how this resource is replenished over time. In a <a href="https://www.nature.com/articles/s43247-023-00858-7">world-first study</a>, we have used caves to show the decades-long decline in rainfall in south-west Australia has reduced the replenishment of groundwater in the region to an 800-year low. </p>
<p>Our findings highlight the immediate threat of climate change to water security for communities in the south-west – the region between Geraldton and Albany, including Perth. Groundwater is the <a href="https://www.ga.gov.au/scientific-topics/water/groundwater/groundwater-use">major source of water</a> used in Perth and many rural towns.</p>
<p>Rainfall across south-west Australia has been decreasing <a href="https://rmets.onlinelibrary.wiley.com/doi/10.1002/joc.1964">since the late 1960s</a>. The region’s drying climate means rainfall may no longer be reliably replenishing its groundwater. </p>
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Read more:
<a href="https://theconversation.com/hidden-depths-why-groundwater-is-our-most-important-water-source-91484">Hidden depths: why groundwater is our most important water source</a>
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<h2>How can caves tell us about groundwater recharge?</h2>
<p><a href="https://theconversation.com/explorers-just-uncovered-australias-deepest-cave-a-hydrogeologist-explains-how-they-form-188064">Caves</a> are natural windows into what’s happening underground. In caves, we can directly observe water on its way to becoming groundwater. This is an advantage when we want to understand how rainfall replenishes groundwater (technically known as groundwater recharge).</p>
<p>In this study, we measured seven stalagmite records and also water dripping from the cave ceiling from caves located in the Leeuwin-Naturaliste National Park. Stalagmites grow up from the cave floor in limestone caves. These structures build up when dripping water deposits minerals onto the cave floor. </p>
<p>In our study area, the mineral calcite (CaCO₃) is deposited in layers. The oldest layers are at the base of the stalagmite and the youngest layers at the top.</p>
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Read more:
<a href="https://theconversation.com/explorers-just-uncovered-australias-deepest-cave-a-hydrogeologist-explains-how-they-form-188064">Explorers just uncovered Australia’s deepest cave. A hydrogeologist explains how they form</a>
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<p>These layers contain a record of past environmental change in the composition of their oxygen isotopes (different naturally occurring forms of oxygen atoms). We measured two of the stable isotopes of oxygen. Our study found both stalagmites and water showed the same change in their chemistry, an “uptick” or rise in the ratio between the two isotopes. </p>
<p>This oxygen isotope record of stalagmites is widely treated as a faithful recorder of changes in rainfall. However, it isn’t that simple in south-west Australia. </p>
<p>We found a change in the oxygen isotope composition of the stalagmites that was ten times greater than the drop in rainfall since the 1960s. This means another process was responsible for the oxygen isotope uptick.</p>
<p>We analysed the water dripping into the caves to help us understand the isotope changes in the stalagmites. We saw differences between water flow types: slower flow through the porous limestone and faster flow along fractures in the limestone, which is known as preferential flow. The faster flow of water had a different oxygen isotope composition, and the uptick in stalagmite oxygen isotopes indicates this flow type has declined in recent decades. </p>
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Read more:
<a href="https://theconversation.com/the-worlds-biggest-source-of-freshwater-is-beneath-your-feet-53874">The world's biggest source of freshwater is beneath your feet</a>
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<h2>What does this mean for groundwater recharge?</h2>
<p>Preferential flow is an important mechanism for rainfall recharge of groundwater. This flow supplies larger volumes of water to groundwater compared to porous flow. </p>
<p>The impact of reduced preferential flow can be seen in the stalagmite image below. A contraction of the growth to the centre of the stalagmite indicates a reduction in drip rate. </p>
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<a href="https://images.theconversation.com/files/534974/original/file-20230630-15-7fkri7.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/534974/original/file-20230630-15-7fkri7.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/534974/original/file-20230630-15-7fkri7.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/534974/original/file-20230630-15-7fkri7.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/534974/original/file-20230630-15-7fkri7.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/534974/original/file-20230630-15-7fkri7.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/534974/original/file-20230630-15-7fkri7.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/534974/original/file-20230630-15-7fkri7.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Golgotha Cave drip water monitoring (right) and stalagmite (left) shows contraction of the growth due to reduced groundwater recharge.</span>
<span class="attribution"><span class="source">Photos: I.J. Fairchild and A. Baker</span>, <span class="license">Author provided</span></span>
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<p>A decline in the local water table from another cave system in the region that began around 1980 matches the beginning of the oxygen isotope uptick. This confirms the decline in rainfall recharge to groundwater.</p>
<p>We now understood how the stalagmite record has captured changes in the groundwater recharge process. We then used the stalagmites to look further back in time to find evidence of previous upticks. </p>
<p>This is the second advantage of having approached this problem using caves. The stalagmite is essentially an archive of past dripwater oxygen isotope composition. Upticks further back in time would indicate if similar reductions in groundwater recharge had occurred. </p>
<p>Importantly, the longer record (shown below) indicates the current reduction in rainfall recharge is unprecedented in the past 800 years. </p>
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<span class="caption">The decline in rainfall in south-west Australia corresponds to an 800-year low in the rate at which groundwater is being replenished.</span>
<span class="attribution"><a class="source" href="https://www.nature.com/articles/s43247-023-00858-7">Priestley et al 2023, Communications Earth & Environment</a></span>
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<h2>What does this mean for the region’s water supply?</h2>
<p>South-west Australia’s drying climate and reduced groundwater recharge have important implications for sustainable use of this resource. Groundwater supplies three-quarters of the water used in the region and future groundwater use is <a href="https://publications.csiro.au/publications/publication/PIlegacy:729">expected to increase</a>. These trends also pose a threat to the plants and animals that live in groundwater-dependent ecosystems.</p>
<p>Australia as a whole depends on finite groundwater resources, which are under mounting pressure. Drought resilience is a research focus of <a href="https://www.csiro.au/en/about/challenges-missions/Drought-Resilience">CSIRO</a>, <a href="https://www.ansto.gov.au/our-science/environment/water-research">ANSTO</a> and <a href="https://www.unsw.edu.au/">UNSW</a>. </p>
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Read more:
<a href="https://theconversation.com/how-drought-is-affecting-water-supply-in-australias-capital-cities-127909">How drought is affecting water supply in Australia’s capital cities</a>
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<p>This research includes looking at ways to improve water security, such as <a href="https://www.wa.gov.au/service/environment/business-and-community-assistance/managed-aquifer-recharge#:%7E:text=MAR%20is%20the%20intentional%20recharge,as%20infiltration%20trenches%20or%20ponds.">water banking</a>. This involves storing water underground using <a href="https://www.csiro.au/en/about/challenges-missions/Drought-Resilience/Water-banking">managed aquifer recharge (MAR) techniques</a>. Excess water resources, such as recycled stormwater, are stored when available and used during dry years or a drought. </p>
<p>We are now working towards extending the record further back in time to 10,000 years ago. Our aim is to understand when groundwater was recharged and under what past climate scenarios. This knowledge will give us a better understanding of the limits and sustainability of this vital resource for communities that rely heavily on groundwater.</p><img src="https://counter.theconversation.com/content/208751/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Stacey Priestley is also affiliated with the University of Adelaide. This research was undertaken while employed by ANSTO.
Other contributors to the research include Dr Allan Griffiths and Dr Karina Meredith of ANSTO and Professor Nerilie Abram of ANU. This research was supported by funding from the Australian Research Council and ANSTO, Australian Synchrotron beamtime, and with the assistance of resources and services from the National Computational Infrastructure (NCI), which is supported by the Australian Government.
</span></em></p><p class="fine-print"><em><span>Andy Baker receives funding from The Australian Research Council </span></em></p><p class="fine-print"><em><span>Pauline Treble receives funding from the Australian Research Council and ANSTO. She is also an Adjunct Senior Lecturer at UNSW Sydney. </span></em></p>South-west Australia relies on groundwater for three-quarters of its water use. But a new study of the region’s caves has found a drying climate is having a dramatic impact on this precious resource.Stacey Priestley, Research Scientist, Environment Business Unit, CSIROAndy Baker, Professor, School of Biological, Earth and Environmental Sciences, UNSW SydneyPauline Treble, Research Scientist, Environment Research Group, Australian Nuclear Science and Technology OrganisationLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2076342023-06-19T14:05:22Z2023-06-19T14:05:22ZAfrican cities and climate change: the real debate is who should pay to fix the problem<figure><img src="https://images.theconversation.com/files/532362/original/file-20230616-25-43c17e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Most mayors and managers of African cities know too well that climate change is real</span> <span class="attribution"><span class="source">GettyImages</span></span></figcaption></figure><p>For most city mayors and managers in Africa, the debate about whether climate change is real is a moot topic. They know it is. They are on the front lines dealing with the impact of droughts, rising sea levels and floods, such as those in the <a href="https://reliefweb.int/report/nigeria/west-and-central-africa-flooding-situation-8-november-2022#:%7E:text=In%20the%20Gulf%20of%20Guinea,people%20were%20affected%20by%20them.">Gulf of Guinea</a>.</p>
<p>Cyclones are more frequent and intense. <a href="https://www.aljazeera.com/news/2023/5/19/world-bank-gives-mozambique-150m-for-cyclone-freddy-recovery">Cyclone Freddy</a>, which hit Malawi, Mozambique and Madagascar in June 2023, is an example. More than 1,000 people were killed.</p>
<p>Climate change’s impact on water supplies is particularly dire. The first city in the world to nearly run out of potable water <a href="https://case.hks.harvard.edu/no-trust-in-miracles-leading-through-a-water-crisis-in-cape-town/">was Cape Town in 2018</a>. Like many cities in Africa, it draws most of its water from a rain-fed system. This meant that its water reservoirs ran close to empty when <a href="https://case.hks.harvard.edu/no-trust-in-miracles-leading-through-a-water-crisis-in-cape-town/">the worst drought in over 300 years</a> started in 2015.</p>
<p>For those responsible for running African cities, the climate change debate is therefore around who should be paying. The question is relevant because African cities contribute the least to climate change. Yet cities in low-income countries face the highest impacts of climate change in terms of frequency and severity of weather events.</p>
<p>A <a href="https://www.worldbank.org/en/publication/thriving?intcid=ecr_hp_headerG_en_ext">recent World Bank</a> report shows that 70% of greenhouse gases are generated in cities. But cities in low-income countries, including most of Africa, have contributed less than 0.2% of this total to date.</p>
<p>So who should foot the bill for mitigating the impacts and adapting infrastructure to future extreme weather events?</p>
<p>Based on <a href="https://astridrnhaas.com/portfolio-2/">my research</a> as well as my work with many African city mayors and managers, I agree that more climate finance must reach African cities directly. Countries that developed on the back of the environment will have to step up their financial support for climate change mitigation and adaptation efforts in lower-income economies, particularly in Africa.</p>
<p>At the same time, African leaders at a national and city level must demonstrate foresight, planning, strong leadership and management so that the climate finance received is properly invested and can benefit their populations.</p>
<h2>Mismatch between cause and effect</h2>
<p>Many African leaders point to the mismatch of cause and effect in the global climate system. All countries, as per the <a href="https://unfccc.int/process-and-meetings/the-paris-agreement">Paris Agreement</a>, are expected to drastically reduce their greenhouse gas emissions to prevent the global temperature rising by 1.5°C.</p>
<p>Former Nigerian vice-president Yemi Osimbajo relayed these concerns in <a href="https://www.economist.com/by-invitation/2022/05/14/yemi-osinbajo-on-the-hypocrisy-of-rich-countries-climate-policies">2022</a>. He denounced the hypocrisy of richer countries which developed through climate unfriendly industries, often in the manufacturing sector. Requiring African countries to develop along low-carbon lines, and thus constrain their energy policy choices, would mean they couldn’t industrialise. Yet industrialisation has been <a href="https://www.un.org/esa/sustdev/publications/industrial_development/3_1.pdf">a precursor to economic growth and development</a>for all developed countries.</p>
<p>Re-balancing this equation so that African cities can urbanise sustainably and unlock productivity will require immediate and major investments in infrastructure. Retrofitting cities once people have already settled comes at a financial as well as political and social cost. </p>
<h2>Costs and benefits</h2>
<p>Cities in Africa and in low-income countries elsewhere will have to make substantial contributions to countering climate change.</p>
<p>Yet there are potentially large benefits. A path to net zero can have substantial positive outcomes for African cities.</p>
<p>For example, for cities like Kampala, combating pollution is already a priority because <a href="https://www.monitor.co.ug/uganda/news/national/poor-air-quality-in-kampala-is-a-time-bomb-health-experts-warn-4223850">rapidly deteriorating air quality</a> has led to an increase in respiratory and other illnesses. Most activities in cities that are related to deteriorating air pollution, particularly around transport and industry, also directly contribute to global climate change. </p>
<p>Thus, tackling one improves the other and enhances overall liveability for residents in these cities.</p>
<p>There are also other benefits. <a href="https://urbantransitions.global/en/publication/financing-africas-urban-opportunity/">A study conducted across 35 cities</a> in Ethiopia, Kenya and South Africa estimated the total benefits of investing in green cities to be about US$1.1 trillion up to 2050. This is equivalent to 250% of these countries’ annual economic output. In addition, it estimated that it could generate returns of US$90 billion in Ethiopia, US$52 billion in Kenya and US$190 billion in South Africa. </p>
<p>The report also found that although there would be job losses from carbon-intensive industries, there could be a net positive gain in the order of hundreds of thousands of new jobs.</p>
<h2>Who should pay</h2>
<p>The same study that calculated the estimated total benefits of greening Africa’s cities also noted that the costs of infrastructure investment were around <a href="https://urbantransitions.global/en/publication/financing-africas-urban-opportunity/">US$280 billion between now and 2050 for all the 35 cities</a> in Ethiopia, Kenya and South Africa. </p>
<p>Yet climate finance flows to these three countries in 2018 totalled only <a href="https://www.climatepolicyinitiative.org/publication/landscape-of-climate-finance-in-africa/">US$4.7 billion, about 1.7%</a> of what’s required.</p>
<p>This is where upper- and middle-income countries come in. They can support their low-income country counterparts by <a href="https://theconversation.com/global-climate-finance-leaves-out-cities-fixing-it-is-critical-to-battling-climate-change-194375">increasing climate finance flows</a>.</p>
<p>Another important source of finance will be from the private sector. Currently, about half of the climate finance globally comes from the private sector. But in Africa it makes up only <a href="https://www.climatepolicyinitiative.org/wp-content/uploads/2022/09/Landscape-of-Climate-Finance-in-Africa.pdf#page=7">14% of the total flows</a>. An even smaller share of this <a href="https://unfccc.int/sites/default/files/resource/SCF%20Forum%202019%20report_final.pdf#page=13">flows directly to cities</a>. </p>
<p>Unlocking this will require reforms at national and city levels. This can also be <a href="https://unfccc.int/sites/default/files/resource/SCF%20Forum%202019%20report_final.pdf">supported by so-called blended finance</a> where private financial flows are encouraged through development finance.</p>
<h2>Managing the finances</h2>
<p>Leadership in African cities will be key. It must ensure that this finance is invested in infrastructure that helps mitigate and adapt to the impact of climate change, and makes cities more compact and liveable. </p>
<p>For example, a city’s shape has a substantial impact on its emissions. The more compact the city, the lower its greenhouse gas emissions. This will require more foresight in planning, as well as information and targeted incentives to shape behaviour. Nearly 1 billion people will settle in African cities between now and 2050. They should do so in areas that are safe and secure.</p>
<p>This is a big ask. African cities are developing in vulnerable locations. For example, the stretch of coastal west Africa between Côte d'Ivoire and Nigeria, including large cities such as Abidjan, Accra, Lomé, Cotonou and Lagos, is the fastest urbanising region in the world. It is projected to become a <a href="https://www.theguardian.com/world/2022/oct/27/megalopolis-how-coastal-west-africa-will-shape-the-coming-century">megalopolis</a> by 2050.</p>
<p>This is the same region that in 2022 had the worst flooding in recorded history, affecting <a href="https://reliefweb.int/report/nigeria/west-and-central-africa-flooding-situation-8-november-2022#:%7E:text=In%20the%20Gulf%20of%20Guinea,people%20were%20affected%20by%20them.">5.9 million people</a>.</p><img src="https://counter.theconversation.com/content/207634/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Astrid R.N. Haas does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>African cities contribute the least to but bear the highest impact of climate change in terms of frequency and severity of weather events.Astrid R.N. Haas, Fellow, Infrastructure Institute, School of Cities, University of TorontoLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2036512023-04-13T12:26:51Z2023-04-13T12:26:51ZThe Colorado River drought crisis: 5 essential reads<figure><img src="https://images.theconversation.com/files/520603/original/file-20230412-18-qqa033.jpg?ixlib=rb-1.1.0&rect=0%2C5%2C3484%2C2001&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Sprinklers water a lettuce field in Holtville, California with Colorado River water. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/this-aerial-view-shows-sprinklers-watering-a-lettuce-field-news-photo/1248577888">Sandy Huffaker/AFP via Getty Images</a></span></figcaption></figure><p>A 23-year western drought has drastically shrunk the Colorado River, which provides <a href="https://www.usbr.gov/climate/secure/docs/2016secure/factsheet/ColoradoRiverBasinFactSheet.pdf">water for drinking and irrigation</a> for Wyoming, Colorado, Utah, New Mexico, Arizona, Nevada, California and two states in Mexico. Under a <a href="https://www.usbr.gov/lc/region/pao/pdfiles/crcompct.pdf">1922 compact</a>, these jurisdictions receive fixed allocations of water from the river – but now there’s not enough water to provide them.</p>
<p>As states try to negotiate ways to share the decreasing flow, the U.S. Department of the Interior is considering <a href="https://www.doi.gov/pressreleases/interior-department-announces-next-steps-protect-stability-and-sustainability-colorado">cuts of up to 25%</a> in allotments for California, Nevada and Arizona. The federal government can regulate these states’ water shares because they come mainly from <a href="https://www.nps.gov/lake/learn/nature/overview-of-lake-mead.htm">Lake Mead</a>, the largest U.S. reservoir, which was created when the Hoover Dam was built on the Colorado River near Las Vegas. </p>
<p>These five articles from The Conversation’s archive explain what’s happening and what’s at stake in the Colorado River basin’s drought crisis. </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/qjWLgaNqK2c?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The Colorado River provides water to 40 million people and some of the fastest-growing cities in the U.S., but its flow is dwindling.</span></figcaption>
</figure>
<h2>1. A faulty river compact</h2>
<p>The idea of negotiating a legally binding agreement to share river water among states was innovative in the 1920s. But the Colorado River Compact made some critical assumptions that have proved to be fatal flaws. </p>
<p>The lawyers who wrote the compact knew that the Colorado’s flow could vary and that they didn’t have enough data for long-term planning. But they still allocated fixed quantities of water to each participating state. “We know now that they <a href="https://theconversation.com/western-river-compacts-were-innovative-in-the-1920s-but-couldnt-foresee-todays-water-challenges-175121">used optimistic flow numbers</a> measured during a particularly wet period,” wrote <a href="https://scholar.google.com/citations?user=LQcyNSwAAAAJ&hl=en">Patricia J. Rettig</a>, head archivist of Colorado State University’s <a href="https://lib.colostate.edu/find/archives-special-collections/collections/water-resources-archive/">Water Resources Archive</a>.</p>
<p>Nor did the compact encourage conservation as the West’s population grew. “When settlers developed the West, their prevailing attitude was that water reaching the sea was wasted, so people aimed to use it all,” Rettig observed. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/western-river-compacts-were-innovative-in-the-1920s-but-couldnt-foresee-todays-water-challenges-175121">Western river compacts were innovative in the 1920s but couldn't foresee today's water challenges</a>
</strong>
</em>
</p>
<hr>
<h2>2. Temporary cuts aren’t big enough</h2>
<p>Western states have known for years that they were taking more water from the Colorado than nature was putting in. But reducing water use is politically charged, since it means imposing limits on such powerful constituencies as farmers and developers. </p>
<p>In 2019, officials from the U.S. government and the seven Colorado Basin states signed a seven-year drought contingency plan that temporarily reduced states’ water allocations. But the plan did not propose long-term strategies for addressing climate change or overuse of water in the region. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1645868976881164289"}"></div></p>
<p>“Since 2000, Colorado River flows have been 16% below the 20th-century average,” wrote water policy experts <a href="https://www.researchgate.net/profile/Brad-Udall">Brad Udall</a>, <a href="https://www.colorado.edu/program/hydrosciences/douglas-kenney#">Douglas Kenney</a> and <a href="https://scholar.google.com/citations?user=hVCNqZUAAAAJ&hl=en">John Fleck</a>. “Temperatures across the Colorado River Basin are now over 2 degrees Fahrenheit (1.1 degrees Celsius) warmer than the 20th-century average, and are certain to continue rising. Scientists have begun using the term ‘aridification’ to describe <a href="https://theconversation.com/western-states-buy-time-with-a-7-year-colorado-river-drought-plan-but-face-a-hotter-drier-future-119448">the hotter, drier climate in the basin</a>, rather than ‘drought,’ which implies a temporary condition.”</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/western-states-buy-time-with-a-7-year-colorado-river-drought-plan-but-face-a-hotter-drier-future-119448">Western states buy time with a 7-year Colorado River drought plan, but face a hotter, drier future</a>
</strong>
</em>
</p>
<hr>
<h2>3. The looming threat of dead pool</h2>
<p>Lake Mead and <a href="https://www.usbr.gov/projects/index.php?id=144">Lake Powell</a>, the other major reservoir on the lower Colorado River, were created to provide water for irrigation and to generate hydropower, which is produced by the force of water flowing through large turbines in the lakes’ dams. If water in either lake drops below the intakes for the turbines, the lake will fall below “minimum power pool” and stop producing electricity. </p>
<p>If water in the lakes dropped even further, <a href="https://theconversation.com/what-is-dead-pool-a-water-expert-explains-182495">they could reach “dead pool</a>,” the point at which water is too low to flow through the dam. This is an extreme scenario, but it can’t be ruled out, University of Arizona water expert <a href="https://robertglennon.net/">Robert Glennon</a> warned. In addition to drought and climate change, he noted, both lakes lie in canyons that “are V-shaped, like martini glasses – wide at the rim and narrow at the bottom. As levels in the lakes decline, each foot of elevation holds less water.”</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-is-dead-pool-a-water-expert-explains-182495">What is dead pool? A water expert explains</a>
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</em>
</p>
<hr>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/520605/original/file-20230412-16-e0mhui.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Infographic of Hoover Dam and water levels where power general and then water flow would stop." src="https://images.theconversation.com/files/520605/original/file-20230412-16-e0mhui.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/520605/original/file-20230412-16-e0mhui.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=448&fit=crop&dpr=1 600w, https://images.theconversation.com/files/520605/original/file-20230412-16-e0mhui.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=448&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/520605/original/file-20230412-16-e0mhui.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=448&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/520605/original/file-20230412-16-e0mhui.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=563&fit=crop&dpr=1 754w, https://images.theconversation.com/files/520605/original/file-20230412-16-e0mhui.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=563&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/520605/original/file-20230412-16-e0mhui.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=563&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This graphic shows the water level in Lake Powell as of November 2022 and the levels that represent minimum power pool and dead pool.</span>
<span class="attribution"><a class="source" href="https://new.azwater.gov/news/articles/2022-03-11">Arizona Department of Water Resources</a></span>
</figcaption>
</figure>
<h2>4. Why hydropower matters</h2>
<p>Climate change and drought are <a href="https://theconversation.com/hydropowers-future-is-clouded-by-droughts-floods-and-climate-change-its-also-essential-to-the-us-electric-grid-182314">stressing hydropower generation</a> throughout the U.S. West by reducing snowpack and precipitation and drying up rivers. This could create serious stress for regional electric grid operators, according to Penn State civil engineers <a href="https://scholar.google.com/citations?user=HoSryoQAAAAJ&hl=en">Caitlin Grady</a> and <a href="https://blogs.gwu.edu/caitlin-grady/team/">Lauren Dennis</a>. </p>
<p>“Because it can quickly be turned on and off, hydroelectric power can help control minute-to-minute supply and demand changes,” they wrote. “It can also help power grids quickly bounce back when blackouts occur. Hydropower makes up about 40% of U.S. electric grid facilities that can be started without an additional power supply during a blackout, in part because the fuel needed to generate power is simply the water held in the reservoir behind the turbine.”</p>
<p>While most hydropower dams are likely here to stay, in Grady’s and Dennis’ view, “climate change will change how these plants are used and managed.”</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/hydropowers-future-is-clouded-by-droughts-floods-and-climate-change-its-also-essential-to-the-us-electric-grid-182314">Hydropower's future is clouded by droughts, floods and climate change – it's also essential to the US electric grid</a>
</strong>
</em>
</p>
<hr>
<h2>5. The resurrection of Glen Canyon</h2>
<p>Lake Powell was created by flooding Glen Canyon, a spectacular swath of canyons on the Utah-Arizona border. As the lake’s water level drops, many side canyons have reemerged. Effectively, climate change is draining the lake.</p>
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<figcaption><span class="caption">A boat trip into zones of Glen Canyon that have been uncovered as water levels drop.</span></figcaption>
</figure>
<p>This is a once-in-a-lifetime opportunity to recover a unique landscape, wrote University of Utah political scientist <a href="https://www.researchgate.net/profile/Daniel-Mccool">Dan McCool</a>. “But <a href="https://theconversation.com/as-climate-change-and-overuse-shrink-lake-powell-the-emergent-landscape-is-coming-back-to-life-and-posing-new-challenges-197340">managing this emergent landscape</a> also presents serious political and environmental challenges.” </p>
<p>In McCool’s view, a key priority should be to give Native American tribes a meaningful role in managing those lands – including cultural sites and artifacts that were flooded when the river was dammed. The river has also deposited massive quantities of sediments in the canyon behind the dam, some of which are contaminated. And as visitors flock to newly accessible side canyons, the area will need staff to manage visitors and protect fragile resources.</p>
<p>“Other landscapes are likely to emerge across the West as climate change reshapes the region and numerous reservoirs decline. With proper planning, Glen Canyon can provide a lesson in how to manage them,” McCool observed.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/as-climate-change-and-overuse-shrink-lake-powell-the-emergent-landscape-is-coming-back-to-life-and-posing-new-challenges-197340">As climate change and overuse shrink Lake Powell, the emergent landscape is coming back to life – and posing new challenges</a>
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</p>
<hr>
<img src="https://counter.theconversation.com/content/203651/count.gif" alt="The Conversation" width="1" height="1" />
Two decades of drought have reduced the river’s flow by one-third compared to historical averages. The Biden administration is considering mandatory cuts to some states’ water allocations.Jennifer Weeks, Senior Environment + Cities Editor, The ConversationLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1977292023-02-02T11:36:15Z2023-02-02T11:36:15ZWater ATMs were introduced in Ghana - and are changing the way people can access this vital resource<figure><img src="https://images.theconversation.com/files/505297/original/file-20230119-16-omk19c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A water-vendor collects water in jerrycans to sell.</span> <span class="attribution"><span class="source">TONY KARUMBA/AFP via Getty Images</span></span></figcaption></figure><p>Universal, safe and reliable water access is a pressing need in the global south. <a href="https://apps.who.int/iris/rest/bitstreams/1474551/retrieve">One-quarter</a> of the world’s population don’t currently have access to clean drinking water. In Ghana, about <a href="https://www.wateraid.org/where-we-work/ghana">5 million</a> people out of a total population of about 31 million lack access to clean, safe water. One person in ten has to spend more than 30 minutes to get drinking water. </p>
<p>Problems are particularly acute in off-grid communities. These are the low-income, rural and peri-urban locations that aren’t connected to municipal or main centralised water supply. </p>
<p>The private sector and other non-governmental providers are getting increasingly involved in filling the gap, sometimes in partnership with the government. Some private water service providers have turned to innovations like “water ATMs”. These automated standpipes are popping up as a way to expand affordable water services. </p>
<p>Powered by solar energy, most water ATMs are designed to operate 24 hours a day. They are low-cost, self-contained, automated water vending machines that store clean water and are most often connected to a water purifying plant that uses groundwater. Customers buy water from the ATMs using a water card, which is topped up with credit via mobile money. </p>
<p>In my recent <a href="https://www.water-alternatives.org/index.php/alldoc/articles/vol15/v15issue3/681-a15-3-10">study</a>, I set out to explore how water ATMs were working in low-income, peri-urban or off-grid locations in Ghana. I found that water ATMs delivered relatively limited operational-level value. And they were changing the water access landscape – not always for the better, from users’ point of view. </p>
<h2>Impact of water ATMs on water access</h2>
<p>The research was conducted in Yawkwei, a peri-urban community in the Ashanti region of Ghana. Here, off-grid households have the choice of using water ATMs or not, but can also rely on other sources such as other private standpipes and community boreholes.</p>
<p>The water ATMs were operated by Safe Water Network, a non-profit organisation dedicated to developing and implementing small, financially viable water initiatives. They were installed at six water standpipes, five with a single ATM and a main station with two ATMs, together serving about 2,000 people. </p>
<figure class="align-right ">
<img alt="Pipe-borne water tap" src="https://images.theconversation.com/files/505076/original/file-20230118-14-dvcqkg.jpg?ixlib=rb-1.1.0&rect=6%2C0%2C2239%2C2997&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/505076/original/file-20230118-14-dvcqkg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/505076/original/file-20230118-14-dvcqkg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/505076/original/file-20230118-14-dvcqkg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/505076/original/file-20230118-14-dvcqkg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/505076/original/file-20230118-14-dvcqkg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/505076/original/file-20230118-14-dvcqkg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">A water ATM point in Yawkwei.</span>
<span class="attribution"><span class="source">Godfred Amankwaa</span></span>
</figcaption>
</figure>
<p>Water ATMs were installed incrementally and used the existing physical, institutional and financial infrastructure in the community. This was done to reduce the cost and the chance of resistance or rejection of the innovation. It relied on what was already in place, such as mobile phones, Safe Water Network’s standpipes, and community actors like water station operators and mobile money agents.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-its-really-worth-to-pipe-water-to-homes-in-rural-zambia-155149">What it's really worth to pipe water to homes in rural Zambia</a>
</strong>
</em>
</p>
<hr>
<p>The study found five main ways in which water ATMs were changing the water access landscape.</p>
<p><strong>Improved water reliability and access:</strong> Water ATMs provided more reliable, flexible and convenient (time-saving) access than former or competing types of off-grid water provision in the community. For instance, people spent on average 15 minutes for a round trip, from home to water ATM and back, compared to 29 minutes at two non-ATM boreholes in the community. Also, people could collect water outside the station caretaker’s or vendor’s hours of business. Collection could fit in around other livelihood activities instead of disrupting them.</p>
<p><strong>Cost and changes in water practices:</strong> Water ATMs brought the relation between costs and water more to the fore for users. Users became more cautious at the point of water collection, since they would be paying for any water spilt. Also, despite the technology not changing water prices or tariffs (20 litres for 10 pesewas), some users claimed they were effectively being charged more because they didn’t get the same volume of water for their money.</p>
<p>A water ATM user said: </p>
<blockquote>
<p>(…) see, this pipe (water ATM point) is closer to me but the prices of late make me visit the other standpipe by the store. When I use this same container (a 40-litre bucket), a Ghana cedi (GH₵1) purchase guarantees five times of that container from other vendors. But instead of getting five times, I only sometimes get four times at same amount when I use the water ATMs. I prefer to walk that distance if I can get an extra container of water. </p>
</blockquote>
<p><strong>Changes in the everyday social relations at the standpipe:</strong> Some of the former informal, social aspects of water access, such as an exchange of gossip, views and concerns during water collection, were reduced.</p>
<p><strong>Roles and power shifts:</strong> New actors became an essential part of water collection. Some were community-based (mobile money agents), others at the national level (the mobile operator MTN) and overseas (eWaterPay). They benefited from consumer payments and use of mobile money related services.</p>
<p><strong>Empowerment vs disempowerment:</strong> Households without water ATM cards or credits, and women who were vendors at off-grid water standpipes, were disempowered. For instance, four women vendors at different water standpipes had lost their livelihoods as a result of water digitalisation. Those with water cards were empowered.</p>
<h2>Bottom-up approach</h2>
<p>Based on my findings, I suggest the following ways to make water ATMs more effective.</p>
<ul>
<li><p>Government should enable a favourable policy and regulatory space for water infrastructure investment and an enabling ecosystem for locally based digital innovations.</p></li>
<li><p>Water service providers, when they introduce innovations, should adopt and build on existing systems and local institutions to create a supportive enabling environment.</p></li>
<li><p>Affordable pricing should be set from the outset to encourage buy-in and usage.</p></li>
<li><p>Government should collaborate with private water providers to incrementally adopt digital water technologies. First they should put in place risk management mechanisms to help prioritise and reduce risks threatening the sustainability of existing infrastructure and for safe and affordable water delivery.</p></li>
</ul><img src="https://counter.theconversation.com/content/197729/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Godfred Amankwaa does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Digital technology is changing the way water is accessed in Ghana. Water ATMs are gaining traction as a means to an end.Godfred Amankwaa, University of ManchesterLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1978412023-01-18T17:02:06Z2023-01-18T17:02:06ZDesalination could give the Middle East water without damaging marine life – but it must be managed carefully<figure><img src="https://images.theconversation.com/files/504863/original/file-20230117-20-8ur47l.jpg?ixlib=rb-1.1.0&rect=48%2C0%2C5400%2C3581&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A saltier Red Sea could threaten its marine life. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/two-free-divers-swimming-over-vivid-222885136">Dudarev Mikhail/Shutterstock</a></span></figcaption></figure><p>More than <a href="https://www.unwater.org/sites/default/files/app/uploads/2021/12/SDG-6-Summary-Progress-Update-2021_Version-July-2021a.pdf">2 billion people</a> live in <a href="https://www.unwater.org/water-facts/water-scarcity#:%7E:text=When%20a%20territory%20withdraws%2025%25%20or%20more%20of%20its%20renewable,UN%2DWater%202021">“water stressed”</a> countries. These are territories where more than 25% of the available freshwater resources are withdrawn for human use each year. </p>
<p>Desalination - the process of removing salt from seawater - is increasingly being used to tackle water scarcity worldwide. Roughly <a href="https://www.sciencedirect.com/science/article/abs/pii/S0048969718349167">16,000 desalination plants</a> now produce 35 trillion litres of freshwater annually. And Jordan, a country located north of the Red Sea, is <a href="https://jordantimes.com/news/local/water-ministry-launches-first-phase-aqaba-amman-water-conveyance-national-project">planning</a> a major desalination plant on the Gulf of Aqaba that will increase its desalination capacity from 4 billion to 350 billion litres each year. </p>
<p>But desalination tends to be energy intensive and produces saline wastewater called brine. On its return to the sea, brine can damage marine ecosystems. <a href="https://www.scientificamerican.com/article/desalination-breakthrough-saving-the-sea-from-salt/">Research</a> suggests that desalination may be making some water bodies, including the Red Sea, the Arabian Gulf and the Mediterranean, saltier.</p>
<p><a href="https://www.sciencedirect.com/science/article/pii/S0011916421005932">We analysed</a> whether current and future desalination plans present a threat to salinity levels in the Red Sea and the Gulf of Aqaba. For both water bodies, the increase in salinity will likely be undetectable and less than natural seasonal variations, in which case it would not harm marine life.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/desalination-may-be-key-to-averting-global-water-shortage-but-it-will-take-time-189169">Desalination may be key to averting global water shortage, but it will take time</a>
</strong>
</em>
</p>
<hr>
<h2>An important marine habitat</h2>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/504665/original/file-20230116-26-tgjeta.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A map of the region surrounding the Red Sea." src="https://images.theconversation.com/files/504665/original/file-20230116-26-tgjeta.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/504665/original/file-20230116-26-tgjeta.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=900&fit=crop&dpr=1 600w, https://images.theconversation.com/files/504665/original/file-20230116-26-tgjeta.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=900&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/504665/original/file-20230116-26-tgjeta.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=900&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/504665/original/file-20230116-26-tgjeta.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1131&fit=crop&dpr=1 754w, https://images.theconversation.com/files/504665/original/file-20230116-26-tgjeta.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1131&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/504665/original/file-20230116-26-tgjeta.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1131&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Red Sea region.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-vector/red-sea-region-political-map-capitals-663310681">Peter Hermes Furian/Shutterstock</a></span>
</figcaption>
</figure>
<p>The Red Sea is connected to the Indian Ocean at its southern end via a narrow and shallow strait. The Gulf of Aqaba branches off its northern end and is connected to the Indian Ocean only through the Red Sea. </p>
<p>Neither water body has a freshwater inflow, so salinity levels are determined by evaporation and the inward and outward flow of water from the Indian Ocean. Water entering the Red Sea flows north where it evaporates and cools, raising its salinity and density. At the head of the Red Sea, this more saline water sinks and flows southwards as a deeper water layer back to the Indian Ocean. </p>
<p>Between where water enters the Red Sea and where salinity peaks at the northern end of the Gulf of Aqaba, salinity <a href="https://www.io-warnemuende.de/tl_files/forschung/meereswissenschaftliche-berichte/mebe50_2002_manasreh.pdf">rises naturally by 10%</a> from roughly 36.8 to 40.6 practical salinity units (psu). One psu is equivalent to 1g of salt dissolved in 1000g of water. Marine life in the region has adapted to the natural salinity level of their location. </p>
<p>Several <a href="https://whc.unesco.org/en/list/262">Unesco Natural Heritage Sites</a> are located in the northern Red Sea, including Sanganeb and Dungonab Bay and Mukkawar Island Marine National Parks. The national parks are home to coral reefs, seagrass beds, mudflats, mangroves and beaches. These habitats hold significant scientific and conservation value as they support a diverse range of marine species, including the endangered <a href="https://www.worldwildlife.org/species/dugong">dugong</a>. </p>
<p>Most marine species can tolerate minor variations in salinity, but they cannot withstand significant and sustained change. <a href="https://www.int-res.com/abstracts/meps/v181/p309-314/">Research</a> reveals that rates of photosynthesis and respiration in <em>Stylophora pistillata</em>, a species of Red Sea coral, falls by as much as 50% when salinity levels are raised from 38 psu to 40 psu. Most colonies of this coral will die if salinity is kept at this level for a sustained period. </p>
<figure class="align-center ">
<img alt="A male dugong swimming along the sea floor alongside small yellow fish." src="https://images.theconversation.com/files/504865/original/file-20230117-20-5a68sl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/504865/original/file-20230117-20-5a68sl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/504865/original/file-20230117-20-5a68sl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/504865/original/file-20230117-20-5a68sl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/504865/original/file-20230117-20-5a68sl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/504865/original/file-20230117-20-5a68sl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/504865/original/file-20230117-20-5a68sl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Sanganeb Marine National Park is home to the endangered dugong.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/rare-big-dugong-male-sea-cow-2195272247">Ivanenko Vladimir/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Making the sea even saltier</h2>
<p>Our research used scenario analysis. This is where a number of plausible future scenarios are modelled and their consequences explored. </p>
<p>The most extreme scenario we developed involved high population growth, rapid economic development and falling desalination costs in the Middle East. Nearly 10 trillion litres of water could be desalinated on the Red Sea coast by 2050 and over 2.5 trillion litres along the Gulf of Aqaba in this case. </p>
<p>A less extreme scenario assumed limited population growth and restrained household water consumption. Nearly 2 trillion litres of water could be desalinated by the Red Sea and over 560 billion litres by the Gulf of Aqaba by 2050. </p>
<p>For both scenarios, salinity in the Red Sea increased by less than 0.1%. This increase would be less than the natural seasonal variation in salinity levels and would likely be undetectable. </p>
<p>The Gulf of Aqaba, however, is smaller and more isolated from the Indian Ocean. Salinity in the north of the Gulf therefore <a href="https://www.io-warnemuende.de/tl_files/forschung/meereswissenschaftliche-berichte/mebe50_2002_manasreh.pdf">varies naturally</a> between 40.2 psu and 40.75 psu. We found that the high growth scenario could increase salinity at the head of the Gulf by 0.5%, from approximately 40.6 psu to 40.8 psu. But even this increase is close to the maximum increase in salinity caused by natural variability. </p>
<p>The medium growth scenario would instead produce a change less than natural seasonal variation and would again be undetectable.</p>
<h2>Tackling water scarcity in the Middle East</h2>
<p>Our research suggests that, if carefully managed, rising rates of desalination may not harm the region’s marine ecosystems. This is particularly important as a considerable growth in desalination is likely to occur in the Middle East</p>
<p>Saudi Arabia plan to construct an entire new city in the country’s north west, called <a href="https://en.wikipedia.org/wiki/Neom">Neom</a>, to accommodate <a href="https://www.reuters.com/world/middle-east/saudi-crown-prince-says-zero-carbon-city-neom-will-likely-be-listed-2024-2022-07-25/">9 million people</a> and water intensive sectors like agriculture by 2045. The city will depend on water desalinated from the Red Sea and Gulf of Aqaba. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/0kz5vEqdaSc?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Neom will accomodate 9 million people by 2045.</span></figcaption>
</figure>
<p>Beyond the vicinity of each desalination plant, increased rates of desalination are unlikely to affect broader salinity levels in the region. But <a href="https://www.sciencedirect.com/science/article/pii/S0011916417307750">good plant design</a> and strict environmental regulations will remain critical to avoid environmental harm. </p>
<p>Plant outfalls, through which brine is channelled towards the sea, must ensure rapid dilution by dispersing brine into the Red Sea’s deeper water layer. Ocean currents can then carry the brine out to the Indian Ocean, where it will be further diluted. </p>
<p>Desalination will continue to grow worldwide. If carefully implemented it can be a crucial tool to tackle water scarcity without damaging fragile marine ecosystems.</p><img src="https://counter.theconversation.com/content/197841/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Jordan is planning a major desalination plant on the Gulf of Aqaba – but will it damage nearby marine ecosystems?Jonathan Chenoweth, Senior Lecturer of Environment and Sustainability, University of SurreyRaya A. Al-Masri, Researcher in Resources Governance and Sustainability, University of SurreyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1951722023-01-02T12:40:42Z2023-01-02T12:40:42ZScientists dig deep and find a way to accurately predict snowmelt after droughts<figure><img src="https://images.theconversation.com/files/497775/original/file-20221128-25-6d5d8u.jpg?ixlib=rb-1.1.0&rect=6%2C324%2C2293%2C1207&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Following historic drought in 2021, reservoir levels dropped down in the Hoover Dam on the Colorado River, which gets its waters from the melting snowpack from the Rocky Mountains of Colorado and Wyoming.</span> <span class="attribution"><a class="source" href="https://pxhere.com/en/photo/623841">(pxhere.com)</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><iframe style="width: 100%; height: 100px; border: none; position: relative; z-index: 1;" allowtransparency="" allow="clipboard-read; clipboard-write" src="https://narrations.ad-auris.com/widget/the-conversation-canada/scientists-dig-deep-and-find-a-way-to-accurately-predict-snowmelt-after-droughts" width="100%" height="400"></iframe>
<p>Where does your water supply come from? </p>
<p>If you live near mountains, for instance in British Columbia, a lot of your water probably comes from mountain snowpack. Over <a href="https://doi.org/10.1038/s41586-019-1822-y">1.9 billion people</a> globally rely on the snow melting and running off from these mountain snowpacks for their water supply.</p>
<p>Accurate predictions of this annual trend is critical for water supply planning. And forecasting models often rely on the <a href="https://www.academia.edu/47863505/Principles_of_snow_hydrology">historical relationship between mountain snowpack and the subsequent water supply</a>. </p>
<p>However, in times of unprecedented drought and a changing climate, these forecasting models seem to no longer be reliable. Following an intense drought in California in 2021, <a href="https://www.theguardian.com/us-news/2021/jun/07/california-drought-oregon-west-climate-change">snowmelt from mountain snowpack delivered significantly less water than historical models predicted</a>, meaning that reservoirs remained drier than anticipated. For the first time in 100 years, water supply models were wrong. </p>
<p>In an attempt to address the gaps in the traditional model, we recently <a href="https://doi.org/10.1029/2022GL100505">developed an updated water supply forecasting model</a> that considers additional factors, like water storage deficits in the soil and bedrock. This new model significantly improves the accuracy of water supply forecasts following drought.</p>
<h2>What are existing water supply models missing?</h2>
<p><a href="https://doi.org/10.1017/CBO9780511535673">Models used for forecasting snowmelt </a>typically consider winter rain and snowpack. But it turns out that water absorbed by the ground matters too. The amount of water absorbed into the soil and bedrock varies from year to year and is especially impacted by drought.</p>
<p>When snow melts or rain falls, almost all of it goes underground first before <a href="https://www.usgs.gov/special-topics/water-science-school/science/runoff-surface-and-overland-water-runoff">heading downstream to water supply systems </a>. The water storage processes below the surface of the ground are key to understanding the ultimate fate of rain and snow in the mountains.</p>
<figure class="align-center ">
<img alt="Schematic diagram of runoff generation in the mountains." src="https://images.theconversation.com/files/497773/original/file-20221128-12-3ska04.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/497773/original/file-20221128-12-3ska04.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=460&fit=crop&dpr=1 600w, https://images.theconversation.com/files/497773/original/file-20221128-12-3ska04.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=460&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/497773/original/file-20221128-12-3ska04.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=460&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/497773/original/file-20221128-12-3ska04.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=578&fit=crop&dpr=1 754w, https://images.theconversation.com/files/497773/original/file-20221128-12-3ska04.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=578&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/497773/original/file-20221128-12-3ska04.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=578&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A diagram showing how water gets from snowpack or rain to water supply systems. Rain and snowmelt seep into the ground. Plants draw water from this region. Once the subsurface is wet, the water flows downstream to water supply systems.</span>
<span class="attribution"><a class="source" href="https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2022GL100505">(Dana Lapides)</a>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The below ground environment is made up of complex layers of soil, fractures and weathered bedrock that can <a href="https://hydrology.usu.edu/rrp/pdfs/ch2.pdf">store, detain and transport water</a>. The details of these processes are complicated, but the overall effect can be likened to a giant sponge. </p>
<p>Over the summer, the ground dries out and it gets wet again with the arrival of rain and snowmelt in winter and spring. Once the ground is wet enough, it starts to drip. This dripping water enters the groundwater and streams and eventually goes into the water supply systems.</p>
<p>How much water drips depends on how much snowmelt and rain is received, which is included in forecasting models. It also depends on how dry the subsurface was to begin with, which is not traditionally included in forecasting models.</p>
<h2>Plants use a lot of water</h2>
<p>How dry the subsurface is this year can depend on how much water the plants used last year (or even over the last few years). In hotter, drier years, plants can use more water from underground, causing the subsurface to dry out more.</p>
<p>Recent studies show us that <a href="https://doi.org/10.1038/s41586-021-03761-3">trees routinely dry up not just soils but also weathered bedrock metres below the surface</a>.</p>
<p>Scientists are still struggling to identify how dry these mountain environments can get and how far below the surface they dry. With a drier subsurface at the start of the year, more snowmelt is needed before water starts to flow downstream to water supply systems. </p>
<p>As droughts become more frequent and intense with climate change, this process could become more important even in regions that historically haven’t faced much drought.</p>
<h2>Measuring the moisture underground</h2>
<p>Directly observing the moisture levels of the ground’s subsurface is difficult, especially when it’s stored in weathered bedrock, which can extend many metres below the ground surface and be challenging to observe. </p>
<p>In our research, we found the most accurate measurements by lowering geophysical instruments down boreholes and taking water content readings at different depths. By comparing these readings over time, we observe how <a href="https://doi.org/10.1073/pnas.1800141115">the subsurface dries out and gets wet again</a>.</p>
<figure class="align-center ">
<img alt="Researcher measures subsurface wetness conditions" src="https://images.theconversation.com/files/497767/original/file-20221128-20492-5u0m49.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/497767/original/file-20221128-20492-5u0m49.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=429&fit=crop&dpr=1 600w, https://images.theconversation.com/files/497767/original/file-20221128-20492-5u0m49.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=429&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/497767/original/file-20221128-20492-5u0m49.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=429&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/497767/original/file-20221128-20492-5u0m49.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=539&fit=crop&dpr=1 754w, https://images.theconversation.com/files/497767/original/file-20221128-20492-5u0m49.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=539&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/497767/original/file-20221128-20492-5u0m49.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=539&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A USDA Forest Service employee uses an instrument to measure the moisture conditions deep underground.</span>
<span class="attribution"><span class="source">(Jamie Hinrichs/USDA Forest Service)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>However, this intensive monitoring is nearly impossible to do over large areas.</p>
<p>While we can’t look directly underground everywhere, <a href="https://hess.copernicus.org/articles/20/1459/2016/">we can track how much water enters (rain and snowmelt) and leaves (plant water use) the ground using satellite-derived data</a>.</p>
<p>By taking a running account of water going in and out of the ground, we can estimate how dry the subsurface is — a metric we call the water storage deficit. </p>
<h2>Water supply models must dig deeper</h2>
<p>Our <a href="https://doi.org/10.1038/s41586-021-03761-3">newly-developed water supply forecasting model</a> accounts for water storage deficits in both soil and bedrock. This has improved post-drought forecast accuracy substantially, taking the probability of error in the calculation of predictions from 60 per cent to about 20 per cent.</p>
<p>Since we can calculate deficits before spring snowmelts, they serve as an early warning sign and can aid water management strategies.</p>
<p>As the climate changes, the water supply challenges in California foreshadow issues that will become increasingly prevalent in British Columbia and other regions reliant on mountain snowpack. Using updated forecasting models in the future can help these regions better prepare for <a href="https://drought.ca.gov/current-drought-conditions/#overview-of-2021">continued water shortages even when snowpack seems normal</a>.</p><img src="https://counter.theconversation.com/content/195172/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dana Ariel Lapides receives funding from Simon Fraser University and the US Forest Service Southwest Pacific Research Station with funds administered through Oak Ridge Institute for Science and Engineering (ORISE). </span></em></p><p class="fine-print"><em><span>David Dralle receives funding from the US Forest Service Pacific Southwest Research Station. </span></em></p><p class="fine-print"><em><span>Jesse Hahm receives funding from Simon Fraser University, the Natural Sciences and Engineering Research Council of Canada, the Canada Foundation for Innovation, and the Pacific Institute for Climate Solutions.</span></em></p><p class="fine-print"><em><span>Daniella Rempe does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Unprecedented droughts leave the subsurface drier than usual, affecting water supply in subsequent years.Dana Ariel Lapides, Postdoctoral Research Fellow, Geography, Simon Fraser UniversityDaniella Rempe, Assistant professor, Jackson School of Geosciences, The University of Texas at AustinDavid Dralle, Research officer, Hydrology, University of California, BerkeleyJesse Hahm, Department of Geography, Assistant Professor, Simon Fraser UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1962942022-12-19T02:09:08Z2022-12-19T02:09:08ZTravelling around Australia this summer? Here’s how to know if the water is safe to drink<figure><img src="https://images.theconversation.com/files/500573/original/file-20221213-3519-oz0t5e.jpg?ixlib=rb-1.1.0&rect=33%2C82%2C5470%2C3523&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://images.pexels.com/photos/9065619/pexels-photo-9065619.jpeg?auto=compress&cs=tinysrgb&w=1260&h=750&dpr=2">Pexels</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Australians are fortunate to have access to safe and healthy drinking water in our towns and cities, which is acknowledged as a <a href="https://www.un.org/sustainabledevelopment/water-and-sanitation/">basic human need</a> globally. Sadly, the World Health Organization estimates about <a href="https://www.who.int/news-room/fact-sheets/detail/drinking-water">2 billion people</a> across the world are not so lucky. </p>
<p>Drinking water is important for our health, but <a href="https://www.health.vic.gov.au/infectious-diseases/food-or-water-borne-illness">water-borne diseases</a> are a common cause of illness. Avoiding water-borne illnesses is particularly important for people with weakened immune systems, or for the very young or aged. Many people travelling around Australia over the summer holidays might wonder if it is still safe to drink the water when they are far from home. </p>
<p>This is a particularly important question this year. After months of very heavy rain across much of eastern Australia, flooding has <a href="https://theconversation.com/drinking-water-can-be-a-dangerous-cocktail-for-people-in-flood-areas-178028">contaminated</a> many rivers and waterways.</p>
<p>Is taste an indication of water quality? And are they some places where you should avoid the tap water altogether?</p>
<h2>Waterways and alerts</h2>
<p>The flooded waterways are the water supply for many regional towns. Poor quality water has made their job of supplying clean and healthy water much more difficult. </p>
<p>In some cases, contamination from flood waters has entered town water treatment and <a href="https://www.narrandera.nsw.gov.au/council/news-and-publications/news-and-media/boiled-water-alert">supply systems</a>. Even Sydney’s giant water supply reservoir, Warragamba Dam, has <a href="https://www.theguardian.com/australia-news/2022/nov/21/sydney-water-restrictions-fears-warragamba-dam-25-percent-safe-to-drink-water-quality-nsw-floods">limited clean water available</a> due to the inflow of poor quality water from a catchment still impacted from bushfires of two summers ago.</p>
<p>As a consequence of flooding, many regional water authorities in Victoria and New South Wales have declared “<a href="https://www.health.nsw.gov.au/environment/water/Pages/boil-water-alert-guidance.aspx">boil water alerts</a>” at various times this year. Most have now been lifted. </p>
<p>At the time of writing, there are still four alerts active in NSW (Eugowra, Narranderra, Forbes and nearby small towns). The Victorian town of Echuca <a href="https://coliban.com.au/boil-water-advisory-echuca-0">issued</a> a boil water alert in October, since lifted, after stormwater entered its water system.</p>
<p>The <a href="https://www.nhmrc.gov.au/about-us/publications/australian-drinking-water-guidelines">Australian Drinking Water Guidelines</a> set the standard for all states and territories. </p>
<p>If you are travelling to a town that has been affected by flooding, you should check with your accommodation provider to see if any boil water alerts are active. </p>
<p>You can also check with the local water authority. In many cases this is the local council. The NSW Health Ministry <a href="https://www.health.nsw.gov.au/environment/water/Pages/drinking-water-quality-and-incidents.aspx">lists</a> water alerts and incidents.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/drinking-water-can-be-a-dangerous-cocktail-for-people-in-flood-areas-178028">Drinking water can be a dangerous cocktail for people in flood areas</a>
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</em>
</p>
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<h2>Going bush?</h2>
<p>But what if you are travelling or camping in a more remote area and are planning to drink from a local stream or an isolated water supply? You might be taking an unnecessary risk if you drink local water without precautions. </p>
<p>If you can’t be certain of the water quality, it is probably best to drink bottled or boiled water. Other water treatment options include chemical disinfection or filtration, but these can be <a href="https://www.cdc.gov/healthywater/drinking/travel/backcountry_water_treatment.html">quite complex and technical</a>. Testing water yourself is also difficult and expensive.</p>
<p>If you <a href="https://www.health.nsw.gov.au/environment/water/Pages/bwa-what-to-do.aspx">boil water</a>, it needs to be a “rolling boil” with big bubbles erupting on the surface. Let it bubble for or <a href="https://www.epa.gov/ground-water-and-drinking-water/emergency-disinfection-drinking-water">at least a minute</a> and store cooled water in a closed container.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/500580/original/file-20221213-1889-c6fji2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="black kettle over campfire" src="https://images.theconversation.com/files/500580/original/file-20221213-1889-c6fji2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/500580/original/file-20221213-1889-c6fji2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/500580/original/file-20221213-1889-c6fji2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/500580/original/file-20221213-1889-c6fji2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/500580/original/file-20221213-1889-c6fji2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/500580/original/file-20221213-1889-c6fji2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/500580/original/file-20221213-1889-c6fji2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Boil water for at least one minute to kill off germs.</span>
<span class="attribution"><a class="source" href="https://images.unsplash.com/photo-1632948237538-422edae2e89c?ixlib=rb-4.0.3&ixid=MnwxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8&auto=format&fit=crop&w=1770&q=80">Unsplash</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/mozzies-are-everywhere-right-now-including-giant-ones-and-those-that-make-us-sick-heres-what-you-need-to-know-194517">Mozzies are everywhere right now – including giant ones and those that make us sick. Here's what you need to know</a>
</strong>
</em>
</p>
<hr>
<h2>Tasting notes</h2>
<p>If you do drink water from an untreated water supply, your senses can give some clues to its safety and quality. Does the water appear clean? Does it smell OK? Is there any cloudiness, discolouration or anything floating or suspended in the water? These signs don’t always mean water is unsafe to drink, but can be an <a href="https://wqa.org/learn-about-water/perceptible-issues/">indicator of poor water quality</a>.</p>
<p>That said, water tastes different in different locations around Australia and it might not taste like what you’re used to. Every year the Australian water industry holds a competition to judge Australia’s best-tasting water. This year Casino, in northern NSW took the <a href="https://wioa.org.au/awards/national-awards/tastetest/">top prize</a>. </p>
<p>A common complaint from travellers is the smell of <a href="https://www.cdc.gov/healthywater/drinking/public/water_disinfection.html">chlorine</a> (or perhaps more accurately chloramines) in town water. These are a family of chlorine compounds added in low doses to water to kill any disease causing microorganisms in water supply systems. These compounds can be <a href="https://www.drinking-water.org/treatment/does-boiling-water-remove-chlorine/">reduced</a> to taste by boiling or by using a commercial water filter. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/its-natural-to-want-to-feed-wildlife-after-disasters-but-it-may-not-help-193863">It's natural to want to feed wildlife after disasters. But it may not help</a>
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</em>
</p>
<hr>
<h2>And don’t swim in it either</h2>
<p>Flooding continues to affect many rivers and communities. Flood waters are working their way down river systems. South Australia is <a href="https://www.ses.sa.gov.au/incidents-and-warnings/incidents-and-warnings-map/warnings/?alertname=River_Murray_Lower&documentid=7&location=Lower+River+Murray&pageTitle=Flood+Watch+and+Act+Message+for+Lower+River+Murray&parentid=401&timestamp=1670562000000">currently affected</a> by flooding of the Murray River, with SES warning of a bigger flood peak later in December. </p>
<p>Even if a flooded river looks inviting for a cooling swim this summer, don’t swim in it. Apart from the drowning risk, or entanglement with debris, medical advice is to avoid contact with flood waters as they are <a href="https://www.epa.vic.gov.au/for-community/environmental-information/water/heavy-rainfall-events/how-to-manage-waste-after-a-flood/health-risks-from-flood-waters#:%7E:text=Floodwater%20is%20often%20contaminated%20by,and%20skin%20infections%2C%20and%20rashes">highly contaminated</a> with disease-causing organisms, including from sewerage overflows. </p>
<p>Even if you’re not drinking it, you don’t want to accidentally ingest this dangerous cocktail.</p><img src="https://counter.theconversation.com/content/196294/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ian Wright has received funding from industry, as well as Commonwealth, NSW and local Government. He formerly worked in the water industry for Sydney Water Corporation.</span></em></p><p class="fine-print"><em><span>Jason Reynolds receives funding from Australian Research Council Research Hub Nutrients in a Circular Economy (NiCE) and Sydney Water.</span></em></p>If you’re on holidays, the water may taste different. But is it safe to drink?Ian A. Wright, Associate Professor in Environmental Science, Western Sydney UniversityJason Reynolds, Senior Lecturer, Western Sydney UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1870422022-11-02T17:27:05Z2022-11-02T17:27:05ZRipple effect: As global freshwater basins dry up, the threat to ecosystems and communities grows<figure><img src="https://images.theconversation.com/files/492515/original/file-20221031-15-781iqe.jpg?ixlib=rb-1.1.0&rect=14%2C85%2C1942%2C1217&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Hundreds of freshwater basins across the world, including the dried-up Santa Olalla permanent freshwater lagoon, in Spain's Doñana National Park, are the most likely to experience social and ecological impacts due to freshwater use.</span> <span class="attribution"><span class="source">(Donana Biological Station/CSIC)</span></span></figcaption></figure><p>When people use freshwater beyond a physically sustainable rate, <a href="https://doi.org/10.1038/nature09440">it sets off a cascade of impacts on ecosystems, people and the planet</a>. These impacts include groundwater <a href="https://calmatters.org/environment/2021/08/california-groundwater-dry/">wells running dry</a>, fish populations becoming stranded <a href="https://hakaimagazine.com/features/what-to-do-with-fish-when-the-river-runs-dry/">before they are able to spawn</a> and <a href="https://www.euronews.com/2022/05/27/spain-s-donana-national-park-under-threat-as-groundwater-pumping-continues">protected wetland ecosystems turning into dry landscapes</a>. </p>
<p>Developments in computer models and satellites have fostered a new understanding of how freshwater is being redistributed around the planet and have made clear the central role that people play in this change. This human impact is so significant that organizations like the United States Geological Survey are <a href="https://www.usgs.gov/special-topics/water-science-school/science/water-cycle-diagrams">redrawing their water cycle diagram</a> to include the impacts of human actions. </p>
<p>Equally important to understanding how people affect freshwater availability, is understanding how people and ecosystems will respond to amplified freshwater challenges including drought, water stress and groundwater depletion. While these challenges impact localized sites, their impacts are scattered across the world. To address this <a href="https://public.wmo.int/en/media/press-release/wake-looming-water-crisis-report-warns">global water crisis</a>, global action is urgently needed. </p>
<p><a href="https://doi.org/10.1038/s41467-022-28029-w">In our recent study</a>, we identified the basins of the world that are most likely to be impacted by two central and interrelated aspects of water scarcity: <a href="https://doi.org/10.1038/srep38495">freshwater stress</a>, which occurs when the consumption of water surpasses renewable water supply, and <a href="https://doi.org/10.1038/s41586-018-0123-1">freshwater storage loss</a>, which is the depletion of freshwater in reservoirs or in groundwater bodies due to persistent overuse. </p>
<h2>Global basins impacted by water scarcity</h2>
<p>We identified <a href="https://www.nature.com/articles/s41467-022-28029-w/figures/3">168 basins</a> across the world that are the most likely to experience social and ecological impacts due to insufficient freshwater availability. These hotspot basins are found on every continent — a clear indication of the widespread, global nature of these challenges.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/492717/original/file-20221101-16-rfgko6.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A map of hotspot basins" src="https://images.theconversation.com/files/492717/original/file-20221101-16-rfgko6.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/492717/original/file-20221101-16-rfgko6.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=339&fit=crop&dpr=1 600w, https://images.theconversation.com/files/492717/original/file-20221101-16-rfgko6.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=339&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/492717/original/file-20221101-16-rfgko6.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=339&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/492717/original/file-20221101-16-rfgko6.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=426&fit=crop&dpr=1 754w, https://images.theconversation.com/files/492717/original/file-20221101-16-rfgko6.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=426&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/492717/original/file-20221101-16-rfgko6.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=426&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Hotspot basins (in orange and red), which are the most likely basins to experience severe social and ecological impacts due to limited freshwater availability.</span>
<span class="attribution"><span class="source">(Xander Huggins)</span></span>
</figcaption>
</figure>
<p>To identify these hotspot basins, we assessed patterns in <a href="https://www.nature.com/articles/s41467-022-28029-w/figures/1">freshwater stress and freshwater storage trends</a> and compared these to patterns in <a href="https://www.nature.com/articles/s41467-022-28029-w/figures/2">societal ability to adapt to environmental hazards</a> and freshwater-based ecological sensitivity indicators. </p>
<p>The hotspot basins are most vulnerable largely because they are likely to experience social and ecological impacts at the same time. <a href="https://www.millenniumassessment.org/documents/document.312.aspx.pdf">People and societies depend on freshwater ecosystems</a> for drinking water, irrigation water, water filtration, erosion control, as cultural sites and for recreation. This means that ecological impacts of freshwater stress and storage loss double as social impacts through degraded ecosystem services. </p>
<h2>Managing vulnerable basins</h2>
<p>Hotspot basins are vulnerable as they are likely to face impacts such as low streamflow that harms aquatic biodiversity, reduced food security as agriculture is heavily reliant on freshwater supply, <a href="https://doi.org/10.1088/1748-9326/aa8ac0">wells running dry</a> and higher potential for <a href="https://www.worldwater.org/conflict/map/">social unrest</a>. </p>
<figure class="align-center ">
<img alt="A field irrigation sprinkler system waters rows of lettuce crops on farmland." src="https://images.theconversation.com/files/488148/original/file-20221004-11-fu8x9h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/488148/original/file-20221004-11-fu8x9h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/488148/original/file-20221004-11-fu8x9h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/488148/original/file-20221004-11-fu8x9h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/488148/original/file-20221004-11-fu8x9h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/488148/original/file-20221004-11-fu8x9h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/488148/original/file-20221004-11-fu8x9h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Declining freshwater supply can affect food security as the agriculture sector heavily relies on it.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>Reducing vulnerability in intertwined societal and environmental systems requires improved policy and management integration across sectors. <a href="https://www.unep.org/explore-topics/disasters-conflicts/where-we-work/sudan/what-integrated-water-resources-management">Integrated Water Resources Management</a> considers and balances social, ecological and hydrological sustainability goals by co-ordinating management across water, land and other related resources. Its <a href="https://www.sdg6monitoring.org/indicator-651/">inclusion in the United Nations Sustainable Development Goal framework</a> highlights its importance.</p>
<p>Our research found that countries including Afghanistan, Algeria, Argentina, Egypt, India, Iraq, Kazakhstan, Mexico, Somalia, Ukraine, Uzbekistan and Yemen have hotspot basins yet low implementation levels of much-needed integrated management practices. </p>
<h2>Prioritizing hotspot basins</h2>
<p>The location of hotspot basins across the world emphasizes the need for global and urgent action. Prioritizing regions based on their potential to experience social and ecological impacts can improve the effectiveness of global freshwater sustainability initiatives.</p>
<p>Our study calculated how vulnerable all the basins in the world were to the social and ecological impacts of freshwater stress and storage loss. We identified the most vulnerable basins as hotspots for global prioritization. However, while we focus on the identified hotspot basins, this does not mean that impacts cannot occur in basins with lower vulnerabilities. </p>
<figure class="align-right ">
<img alt="A dry section of a river." src="https://images.theconversation.com/files/487948/original/file-20221004-26-t92w96.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/487948/original/file-20221004-26-t92w96.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=900&fit=crop&dpr=1 600w, https://images.theconversation.com/files/487948/original/file-20221004-26-t92w96.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=900&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/487948/original/file-20221004-26-t92w96.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=900&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/487948/original/file-20221004-26-t92w96.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1131&fit=crop&dpr=1 754w, https://images.theconversation.com/files/487948/original/file-20221004-26-t92w96.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1131&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/487948/original/file-20221004-26-t92w96.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1131&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A dry section of the Cowichan River on Vancouver Island, B.C.</span>
<span class="attribution"><span class="source">THE CANADIAN PRESS/Kevin Rothbauer</span></span>
</figcaption>
</figure>
<p>For instance, only a number of Canadian basins — all located in the prairies — are identified with moderate vulnerability in our global study. Yet, <a href="https://watershedsentinel.ca/articles/groundwater-pumping-drains-rivers-in-bc-and-globally/">dry streams on Vancouver Island</a>, <a href="https://doi.org/10.1080/07011784.2014.885677">falling groundwater levels in the Lower Mainland</a>, <a href="https://www.cbc.ca/news/canada/manitoba/drought-agriculture-disaster-rm-of-armstrong-manitoba-1.6100138">crop yields affected by drought throughout the prairies</a> and potential for <a href="https://www.cbc.ca/news/canada/nova-scotia/n-s-panel-discussing-climate-change-impacts-on-well-water-groundwater-1.6210051">salt-water intrusion along the East Coast</a> are all instances of freshwater security challenges being faced in Canada. </p>
<p>With <a href="https://thenarwhal.ca/saskatchewan-irrigation-project-explained/">massive expansion planned for irrigated agriculture in Saskatchewan</a> and increasing <a href="https://watershedwatch.ca/wp-content/uploads/2019/09/2019-09-24-Tapped-Out-RGB.pdf">water scarcity across British Columbia</a>, Canada’s current (and enviable) position of being able to act proactively on water security challenges is rapidly shrinking.</p>
<h2>Global action starts locally</h2>
<p>While our study took a global focus, the approach of mapping vulnerability to guide priority setting can be applied at other geographical scales. For instance, this analysis could be refined and applied to Canada or specific provinces or cities using globally unavailable data that may be available for these jurisdictions.</p>
<p>These insights could help boost urgency to act on the emerging national water crisis, aid the <a href="https://gwf.usask.ca/documents/meetings/water-security-for-canada/WaterSecurityForCanada_April-25-2019-2pg1.pdf">modernization of the Canada Water Act</a> or help identify communities that would benefit most from <a href="https://poliswaterproject.org/files/2019/10/POLIS-WSP2019-6e1-web.pdf">water sustainability plans</a> in British Columbia.</p>
<p>While global studies, such as ours, are helpful at systematically highlighting regions for prioritization, they do not — and should not — provide explicit solutions. Rather, in such intricate social and ecological environments, actions to reduce impacts need to be attuned to place-based social norms, cultural values, hydrological conditions and local knowledge systems. </p>
<p>Our hotspot basins can help guide such community-driven local action to help conserve freshwater resources that are most under threat and mitigate the ripple effects of these threats on people and ecosystems.</p><img src="https://counter.theconversation.com/content/187042/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Xander Huggins receives funding from the Natural Sciences and Engineering Research Council of Canada through a doctoral Canada Graduate Scholarship.</span></em></p>While we know how global changes in freshwater pose risks to humans and ecosystems, we know less about how people and ecosystems will respond to these global freshwater challenges.Xander Huggins, PhD Candidate in the Department of Civil Engineering (University of Victoria) and the Global Institute for Water Security (University of Saskatchewan), University of VictoriaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1925652022-11-01T15:48:48Z2022-11-01T15:48:48ZThe Horn of Africa has had years of drought, yet groundwater supplies are increasing – why?<figure><img src="https://images.theconversation.com/files/492348/original/file-20221028-64500-j3d8z7.jpg?ixlib=rb-1.1.0&rect=14%2C441%2C4955%2C3300&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Harvepino / shutterstock</span></span></figcaption></figure><p>The Horn of Africa – which includes Somalia, Ethiopia, Kenya and some surrounding countries – has been hit by increasingly frequent and devastating droughts. Despite this, it seems the region has an increasing amount of groundwater. And this water could help support drought-stricken rural communities. </p>
<p>That’s the key finding from our <a href="https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2022GL099299">new research</a>, in which we discovered that while overall rainfall is decreasing, an increase in “high-intensity” rainfall has led to more water being stored deep underground. It’s a paradoxical finding, yet one that may help one of the world’s most vulnerable regions adapt to climate change. </p>
<p>In the Horn of Africa, rural communities live in a constant state of water scarcity punctuated by frequent periods of <a href="https://theconversation.com/somalia-four-lessons-from-past-experience-of-dealing-with-famine-192067">food insecurity</a>. People there rely on the “long rains” between March and May and the “short rains” between October and December to support their lives and livelihoods. </p>
<p>As we write this, the region’s drylands are experiencing a <a href="https://public.wmo.int/en/media/news/greater-horn-of-africa-faces-5th-failed-rainy-season">fifth consecutive season of below-average rainfall</a>. This has left <a href="https://news.un.org/en/story/2022/08/1125552">50 million people in acute food insecurity</a>. The droughts have caused water shortages, livestock deaths, crop failures, conflict and even <a href="https://www.cambridge.org/core/journals/bjpsych-international/article/mental-health-and-climate-change-in-africa/65A414598BA1D620F4208A9177EED94B">mental health challenges</a>. </p>
<p>The drought is so severe that it is even affecting <a href="https://edition.cnn.com/2022/10/05/africa/kenya-drought-wildlife-climate-intl-cmd/index.html">zebras</a>, <a href="https://www.theguardian.com/world/2021/dec/14/six-dead-giraffes-kenya-drought-horror-captured-picture">giraffes</a> and other wildlife, as all surface waters are drying up and edible vegetation is becoming scarce. Worryingly, a sixth failed rainy season has already been <a href="https://blog.chc.ucsb.edu/?p=1240">predicted</a> for March to May 2023. </p>
<h2>Long rains down, short rains up</h2>
<p>In a <a href="https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2022GL099299">new paper</a> we investigated changes in seasonal rainfall in the Horn of Africa over the past 30 years. We found the total rainfall within the “long rains” season is declining, perhaps related to the <a href="https://rmets.onlinelibrary.wiley.com/doi/10.1002/qj.3266">warming of a particular part of the Pacific Ocean</a>. However, rainfall is increasing in the “short rains”. That’s largely due to a climate phenomenon known as the <a href="https://www.bbc.co.uk/news/science-environment-50602971">Indian Ocean Dipole</a>, when a warmer-than-usual Indian Ocean produces higher rainfall in east Africa, similar to El Niño in the Pacific.</p>
<p>We then investigated what these rainfall trends mean for water stored below ground. Has it decreased in line with declining “long rains”, or risen due to the increasing “short rains”?</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/492790/original/file-20221101-26-5aqn3j.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Map of East Africa" src="https://images.theconversation.com/files/492790/original/file-20221101-26-5aqn3j.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/492790/original/file-20221101-26-5aqn3j.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=682&fit=crop&dpr=1 600w, https://images.theconversation.com/files/492790/original/file-20221101-26-5aqn3j.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=682&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/492790/original/file-20221101-26-5aqn3j.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=682&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/492790/original/file-20221101-26-5aqn3j.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=857&fit=crop&dpr=1 754w, https://images.theconversation.com/files/492790/original/file-20221101-26-5aqn3j.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=857&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/492790/original/file-20221101-26-5aqn3j.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=857&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Horn of Africa borders the Red Sea, the Gulf of Aden and the Indian Ocean.</span>
<span class="attribution"><span class="source">Peter Hermes Furian / shutterstock</span></span>
</figcaption>
</figure>
<p>To do this we made use of a pair of satellites which orbit repeatedly and detect small changes in the Earth’s gravitational field that can be interpreted as <a href="https://edo.jrc.ec.europa.eu/documents/factsheets/factsheet_grace_tws_anomaly.pdf">changes in the mass of water storage</a>. If there’s a significant increase in water storage underground, then the satellite will record a stronger gravity field at that location compared to the previous measurement, and vice versa. From this, the mass of water added or lost in that location can be determined. </p>
<p>Using these <a href="https://www.jpl.nasa.gov/missions/gravity-recovery-and-climate-experiment-grace">satellite-derived</a> estimates, we found that water storage has been increasing in recent decades. The increase correlates with the increasing “short rains”, and has happened despite the “long rains” getting drier.</p>
<p>Given that the long rains deliver more seasonal rain than the short rains, we wanted to understand the paradoxical finding that underground water is increasing. A clue is given by examining how rainfall is converted into groundwater in drylands. </p>
<p>When rain is light and drizzly, much of the water that reaches the ground dampens the soil surface and soon evaporates back into the warm, dry atmosphere. To become groundwater, rainfall instead needs to be intense enough so that water will quickly infiltrate deep into the soil. This mostly happens when lots of rain falls at once and causes dry riverbeds to fill with water which can then <a href="https://onlinelibrary.wiley.com/doi/abs/10.1002/hyp.13847">leak into underground aquifers</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/492791/original/file-20221101-22-62x1oe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="People stand in river, rainy sky." src="https://images.theconversation.com/files/492791/original/file-20221101-22-62x1oe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/492791/original/file-20221101-22-62x1oe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/492791/original/file-20221101-22-62x1oe.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/492791/original/file-20221101-22-62x1oe.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/492791/original/file-20221101-22-62x1oe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/492791/original/file-20221101-22-62x1oe.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/492791/original/file-20221101-22-62x1oe.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Heavy rains fill a dry river bed in the Somali region of Ethiopia.</span>
<span class="attribution"><span class="source">Stanley Dullea / shutterstock</span></span>
</figcaption>
</figure>
<p>These most intense rainfall events are increasing in the “short rains”, in line with the overall increase in total rain in that season. And despite a decrease in overall rainfall in the “long rains”, intense rainfall has remained consistently high over time. This means that both rainy seasons have enough intense rainfall to increase the amount of water stored underground. </p>
<p>Finally, we demonstrated that the increasing water storage in this region is not connected to any rise in soil moisture near the surface. It therefore represents “banked” water that resides deep below ground and likely contributes to a growing regional groundwater aquifer in this region. </p>
<h2>Groundwater can help people adapt to climate change</h2>
<p>While <a href="https://fews.net/east-africa">early warning networks</a> and <a href="https://www.unicef.org.uk/donate/east-africa-crisis/?https://www.unicef.org.uk/donate/east-africa-crisis/&gclid=Cj0KCQjwy5maBhDdARIsAMxrkw2qNJBJSlL4Kl1CIwwB4p4nhyK5PWQnqvPy1J4FeyXsM-zmF9hqWV4aAnTcEALw_wcB">humanitarian organisations</a> focus on the urgent impacts of drought, our new research points to a silver lining that may support long-term climate adaptation. Those rising groundwater supplies we have identified may potentially be exploited to support people in rural areas whose food and water are increasingly insecure. </p>
<p>But there are some caveats. First, we have not assessed the depth of the available groundwater across the region, but we suggest that the water table is shallow enough to be affected by seasonal rainfall. This means it may also be shallow enough to support new bore holes to extract it. Second, we do not know anything about the quality of the stored groundwater and whether it can be deemed suitable for drinking. Finally, we do not know exactly what will happen if the most extreme droughts of the past few seasons continue and both long and short rains fail, causing intense rainfall to decrease too. </p>
<p>Nevertheless, our findings point to the need for extensive groundwater surveys across the Horn of Africa drylands to ascertain whether this increasing water resource may be viable enough to offset the devastating droughts. Groundwater could potentially irrigate fields and provide drinking water for humans and livestock, as part of a strategy to help this vulnerable region adapt to the effects of climate change.</p><img src="https://counter.theconversation.com/content/192565/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michael Singer received funding for this work from the European Union, The Royal Society, and UK Research and Innovation. </span></em></p><p class="fine-print"><em><span>Katerina Michaelides receives funding from the Royal Society, the EU Horizon 2020 funding program and UKRI. </span></em></p><p class="fine-print"><em><span>Markus Adloff received funding from UK Research and Innovation.</span></em></p>High intensity rain has actually increased, which is topping up underground water stores.Michael Singer, Professor in Physical Geography (Hydrology and Geomorphology), Cardiff UniversityKaterina Michaelides, Associate Professor, School of Geographical Sciences , University of BristolMarkus Adloff, PostDoctoral Researcher, Earth System Modelling, University of BernLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1907002022-09-26T16:29:53Z2022-09-26T16:29:53ZThe UK’s water industry is broken – here’s how to fix it<figure><img src="https://images.theconversation.com/files/486247/original/file-20220923-22-4pptt7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">As periods of drought become more common, the consequences of an ill functioning water sector will be severe.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/stainesupon-thames-31122020-england-english-neighbourhood-1886829592">malgosia janicka/Shutterstock</a></span></figcaption></figure><p>Prolonged <a href="https://www.theguardian.com/environment/2022/jul/25/uk-drought-extreme-heat-dry">periods</a> of intense heat affected large parts of the UK and Europe this summer. These conditions forced parts of the UK into an official drought, with <a href="https://www.theguardian.com/environment/2022/aug/03/south-east-water-announces-hosepipe-ban-kent-and-sussex">restrictions</a> on water use imposed for the first time since 2012. Despite recent autumnal weather, parts of the country remain firmly <a href="https://theconversation.com/why-the-drought-isnt-over-even-though-its-rained-all-week-190812">in drought</a>.</p>
<p>Droughts are increasingly a feature of the UK’s climate. The UK has experienced at least <a href="https://link.springer.com/book/10.1007/978-3-030-65578-5#otherversion=9783030655785">three major drought episodes</a> since 2000. The risk has grown so acute that, <a href="https://www.gov.uk/government/speeches/escaping-the-jaws-of-death-ensuring-enough-water-in-2050">unless action is taken</a>, in around 25 years England will be unable to supply its own water needs.</p>
<p>This threat has materialised faster than many anticipated. England’s reservoirs reached their <a href="https://www.bloomberg.com/news/articles/2022-08-12/total-water-in-england-s-reservoirs-is-at-lowest-level-since-1995">lowest level</a> since 1995 this summer. Regardless, some water companies <a href="https://www.theguardian.com/environment/2022/aug/03/water-companies-resist-government-calls-hosepipe-bans-drought?amp;amp;amp">resisted calls</a> for usage restrictions. </p>
<p>To ensure it is equipped to deal with future challenges, the UK’s water industry requires reform. To do this, we should look to regions where water is already scarce. In California, for example, shared knowledge is ensuring that water is managed in a responsible and sustainable way.</p>
<h2>Why is the water industry not working?</h2>
<p>England and Wales are the only countries in the world with a fully privatised water industry. There are only two dozen water companies across England and Wales. Each is granted a licence to operate from the industry regulator, <a href="https://www.ofwat.gov.uk/">Ofwat</a>, and holds a <a href="https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/259664/pb14058-water-bill-industry-structure-regulation.pdf">regional monopoly</a> making them responsible for providing water for a particular geographical area. </p>
<p>This structure, combined with high infrastructure costs, restricts the chance for new companies to enter the market. Meanwhile consumers are unable to switch providers. With competition thus limited, water companies can get away with minimal investment. Investment in critical water infrastructure has been slashed by <a href="https://www.ft.com/content/a5669358-bc40-4065-a864-88fa671e71d4">up to a fifth</a> over the past 30 years as a result. </p>
<p>Subsequently, leakage rates are high. Despite recent efforts to address leakage, Thames Water still loses <a href="https://www.itv.com/news/meridian/2022-08-11/thames-water-admits-it-leaks-millions-of-litres-per-day-as-hosepipe-ban-looms">600 million litres</a> of water each day. </p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/486246/original/file-20220923-8064-zn3w0w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A man in a reflective orange jacket locating a water leak on a town road." src="https://images.theconversation.com/files/486246/original/file-20220923-8064-zn3w0w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/486246/original/file-20220923-8064-zn3w0w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=900&fit=crop&dpr=1 600w, https://images.theconversation.com/files/486246/original/file-20220923-8064-zn3w0w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=900&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/486246/original/file-20220923-8064-zn3w0w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=900&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/486246/original/file-20220923-8064-zn3w0w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1131&fit=crop&dpr=1 754w, https://images.theconversation.com/files/486246/original/file-20220923-8064-zn3w0w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1131&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/486246/original/file-20220923-8064-zn3w0w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1131&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A water engineer locating a burst pipe.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/bradford-on-avon-may-21st-2019-1413981746">Starsphinx/Shutterstock</a></span>
</figcaption>
</figure>
<p>Maintenance also happens slowly. A <a href="https://www.ft.com/content/65e8979e-af3d-11e7-beba-5521c713abf4">past report</a> concluded that it would take Thames Water 357 years to renew its network. Yet pipes have a lifespan of only 50 years. </p>
<p>This situation is exacerbated by weak regulation. The sector has a small number of actors, comprised of water companies, consultancies and regulators. Workers frequently move between these organisations. </p>
<p>Such impartiality interferes with regulatory decisions as former water company employees turned regulators may not wish to inflict excessive strain upon former colleagues. As customers’ water bills rose, Anglian Water paid a <a href="https://www.ft.com/content/a5669358-bc40-4065-a864-88fa671e71d4">£92 million dividend</a> to its owners in June, a payout within its regulatory limits. </p>
<p>Distrust has also become a key feature of the UK’s water industry, impeding its ability to function effectively. Numerous scandals, including the <a href="https://www.theguardian.com/environment/2022/may/13/sewage-dumps-into-english-rivers-widespread-criminal-inquiry-suspects">discharge of sewage</a> into water sources and the imprudent award of <a href="https://www.theguardian.com/environment/2022/aug/08/ban-bonuses-for-water-firm-bosses-until-they-fix-leaky-pipes-say-lib-dems">bonuses</a> have aggravated customers. Attempting to appease customers, water companies are reluctant to agree to further compromises over service quality.</p>
<p>Even then a lack of dialogue between water companies and the public restricts understanding of water scarcity. This fuels the popular perception of the UK as a “wet” country, which may contribute to the public’s low willingness to restrict their own water use.</p>
<h2>Whipping water companies into place</h2>
<p>Despite the industry’s continual failure to service society’s water needs, consecutive governments seem set on not nationalising. How does research instead suggest the UK can fix its broken private water model?</p>
<p>There is currently little room for public contribution to water resource management. However, local communities often have an abundance of knowledge regarding water resources. This includes records of localised water level, seasonal water flow, and weather data.</p>
<p><a href="https://doi.org/10.3389/fenvs.2021.574975">Research</a> indicates that shared knowledge can enhance water management. One option is <a href="https://link.springer.com/book/10.1007/978-3-030-65578-5#otherversion=9783030655785">water stewardship</a>. </p>
<p>Water stewardship is the concept of using water in a socially responsible, sustainable and economically beneficial way. This is achieved by including various stakeholders including government, businesses and commmunity groups throughout the management process. This ensures the development of strategies that account for a range of shared water-related risks.</p>
<p>Water stewardship is being used with success in <a href="https://drought.ca.gov/current-drought-conditions/">California</a>, which is currently experiencing its second extreme drought in ten years. The <a href="https://cawateraction.org/">California Water Action Collaborative</a> brings together environmental groups, agricultural producers, and major companies operating in California to pursue collective projects to improve the region’s water security. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/486315/original/file-20220923-8064-s7m7vy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A river channel surrounded by green trees against a cloudy blue sky." src="https://images.theconversation.com/files/486315/original/file-20220923-8064-s7m7vy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/486315/original/file-20220923-8064-s7m7vy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=896&fit=crop&dpr=1 600w, https://images.theconversation.com/files/486315/original/file-20220923-8064-s7m7vy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=896&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/486315/original/file-20220923-8064-s7m7vy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=896&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/486315/original/file-20220923-8064-s7m7vy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1126&fit=crop&dpr=1 754w, https://images.theconversation.com/files/486315/original/file-20220923-8064-s7m7vy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1126&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/486315/original/file-20220923-8064-s7m7vy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1126&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Through the California Water Action Collaborative, the Consumnes river is managed sustainably.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/summer-marsh-scene-green-grass-blue-3406954">Terrance Emerson/Shutterstock</a></span>
</figcaption>
</figure>
<p>The management of the <a href="https://cawateraction.org/cwac-projects-list/cosumnes-river">Cosumnes river</a> in northern California is one such project. Here, the Freshwater Trust, a Californian conservation group, are collaborating with regional stakeholders to develop a recycled water plant to irrigate more than <a href="https://www.regionalsan.com/harvest-water">16,000 acres</a> of agricultural land in the Sacramento region. The plant will also support drinkable water supplies in the region in the future.</p>
<p>In such ways, the Californian public contribute to management and actively engage water companies in conversation. This will ensure greater resilience towards drought, but also increase the acceptability of drought management measures such as usage restrictions. </p>
<p>The UK’s water sector is clearly not working. The need for an industry that does not shirk responsibility for water management will become clear as water insecurity becomes an increasing feature of life. As shown in California, through collaboration it is possible to re-establish the value of water.</p><img src="https://counter.theconversation.com/content/190700/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kevin Grecksch has received funding from NERC, ESRC and the British Academy. </span></em></p>Unless action is taken, the UK will be unable to supply its own water needs in the future – we should look to water-scarce regions such as California for inspiration.Kevin Grecksch, Departmental Lecturer and Course Director MSc in Water Science, Policy and Management, University of OxfordLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1887952022-08-31T20:02:42Z2022-08-31T20:02:42ZThe ‘yuck factor’ pushes a premier towards desalination yet again, but history suggests recycled water’s time has come<p>A battle is brewing in South-East Queensland over water. Despite heavy rains and flooding, the water supply authority, Seqwater, has <a href="https://www.brisbanetimes.com.au/politics/queensland/seq-does-not-have-enough-drinking-water-for-booming-population-20210818-p58jqd.html">flagged the need</a> to find more water sources to keep up with urban growth. </p>
<p>Premier Annastacia Palaszczuk has already <a href="https://www.couriermail.com.au/news/queensland/plan-for-1bn-desalination-plant-despite-premier-minister-split/news-story/f4a89e40cce7606cd397345dc8f0ac99">expressed a preference</a> for building a desalination plant on the Sunshine Coast instead of using <a href="https://f.hubspotusercontent30.net/hubfs/14568786/Fact%20Sheets/Water_Recycling_Fact_Sheet.pdf">recycled water</a>. Perhaps her government <a href="https://www.couriermail.com.au/news/queensland/qld-politics/qld-water-policy-mps-dodge-issue-of-water-recycled-from-sewage/news-story/21ecffc6603fbedf1f861a28c1495961">wants to avoid</a> a repeat of the divisive 2006 <a href="https://ro.uow.edu.au/cgi/viewcontent.cgi?article=1752&context=commpapers">debate over water recycling</a> in Toowoomba – dubbed “<a href="https://www.brisbanetimes.com.au/politics/queensland/scare-campaign-over-recycled-water-could-be-worse-than-poowoomba-turnbull-20210824-p58lfd.html">Poowoomba</a>” at the time.</p>
<p>Our new book, <a href="https://www.cambridge.org/au/academic/subjects/history/environmental-history/cities-sunburnt-country-water-and-making-urban-australia?format=HB">Cities in a Sunburnt Country</a>, traces the fraught history with recycled water in Australia’s biggest cities. A focus on expanding capacity to extract or produce more potable water has dominated urban water policy in Australia. City residents have come to expect abundant water from sources they perceive as “pure”: dams, aquifers and desalination. </p>
<p>Continuing down this path is not sustainable. Yet once again a state government looks set to pursue the <a href="https://theconversation.com/cities-turn-to-desalination-for-water-security-but-at-what-cost-110972">costly</a>, <a href="https://f.hubspotusercontent30.net/hubfs/14568786/Fact%20Sheets/Desalination_Fact_Sheet.pdf">energy-intensive</a> desalination option.</p>
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Read more:
<a href="https://theconversation.com/when-water-is-scarce-we-cant-afford-to-neglect-the-alternatives-to-desalination-111249">When water is scarce, we can't afford to neglect the alternatives to desalination</a>
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<h2>A history of being diverted by desalination</h2>
<p>Desalination has been a reassuring project in times of crisis, but has not always proven its value. In response to the impacts on city water supplies of the Millennium Drought (2001–09), <a href="https://en.wikipedia.org/wiki/List_of_desalination_plants_in_Australia">desalination plants were built</a> to supply most of the capital cities. </p>
<p>In 2006, Perth residents became the <a href="https://theconversation.com/river-deep-policy-dry-western-australias-perpetual-struggle-for-water-900">first in Australia to drink desalinated seawater</a>. By 2012, desalination plants had been built to supply Sydney, Melbourne, Adelaide and Brisbane.</p>
<p>A <a href="https://www.smh.com.au/national/city-desalination-plant-is-not-the-solution-poll-20051214-gdmmph.html">2005 poll</a> commissioned by “SCUD” (Sydney Community United against Desalination) found 60% of Sydney residents opposed a desalination plant. The following year a <a href="https://www.parliament.nsw.gov.au/lcdocs/inquiries/2050/A%20sustainable%20water%20supply%20for%20Sydney.pdf">parliamentary inquiry</a> concluded such a plant would not be needed if the government pursued water recycling and reuse strategies. The plant was still built. </p>
<p>The Victorian government also <a href="https://www.theage.com.au/national/victoria/new-water-minister-open-to-using-desalination-plant-if-victoria-water-supplies-hit-critical-levels-20141217-1299sa.html">faced a backlash</a> when it announced in 2007 a privately financed plant near Wonthaggi on the Bass Coast. Completed in 2012, the plant was mothballed until 2017.</p>
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Read more:
<a href="https://theconversation.com/cities-turn-to-desalination-for-water-security-but-at-what-cost-110972">Cities turn to desalination for water security, but at what cost?</a>
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<h2>There are better alternatives</h2>
<p>In 2011 the <a href="https://www.pc.gov.au/inquiries/completed/urban-water/report/urban-water-overview.pdf">Productivity Commission found</a> only some desalination infrastructure was justified. Other projects could have been deferred, made smaller, or replaced by lower-cost sources, including recycled water.</p>
<p>During the Millennium Drought, the Beattie government built the Brisbane Water Grid connecting all major dams in South East Queensland. By 2008, the 600km network of pipelines was connected to the A$2.9 billion Western Corridor Recycled Water Scheme. The state-owned desalination plant at Tugun on the Gold Coast was completed a year later. </p>
<p>Queensland had opted for a desal quick fix. The government went for the high-cost, high-energy and high-emissions road, instead of more sustainable approaches to potable water supplies and climate change. Today, while South-East Queensland’s population and water use <a href="https://www.seqwater.com.au/sites/default/files/2019-09/FACT_SHEET_-_Water_Security_Program.pdf">continue to grow</a>, the recycled water scheme <a href="https://www.seqwater.com.au/sites/default/files/2021-12/Western%20Corridor%20Recycled%20Water%20Scheme%20%28WCRWS%29%20Recycled%20Water%20Management%20Plan%20%28RWMP%29%20Annual%20Report%202020-21.pdf">only provides water for industry</a>.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/sydneys-dams-may-be-almost-full-but-dont-relax-because-drought-will-come-again-170523">Sydney's dams may be almost full – but don't relax, because drought will come again</a>
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<h2>Recycled water is a well-proven approach</h2>
<p>Cities worldwide commonly use recycled wastewater to add to drinking water supplies, including Los Angeles, Singapore and London. Most residents of Australian cities are also <a href="https://theconversation.com/more-of-us-are-drinking-recycled-sewage-water-than-most-people-realise-92420">drinking some treated wastewater</a>. Hinterland towns discharge treated wastewater into rivers that eventually flow into dams such as Warragamba and Wivenhoe (which supply Sydney and Brisbane respectively). </p>
<p>In 2018, the Productivity Commission’s <a href="https://www.pc.gov.au/inquiries/completed/water-reform#report">National Water Reform Report</a> recommended an integrated approach that included reusing urban wastewater and/or stormwater. Implementation has been slow, however. Only one Australian capital has officially overcome the “yuck factor”. </p>
<p>Perth stores treated wastewater in aquifers beneath the suburbs before returning it to the city’s taps. The state-owned Water Corporation’s 50-year plan, <a href="https://www.watercorporation.com.au/-/media/WaterCorp/Documents/Our-Water/Sustainability-and-Innovation/Securing-Supply/Water-forever-50-year-plan.pdf">Water Forever</a>, includes a 60% increase in wastewater recycling. Even then the state’s main strategy for eliminating the gap between future water demand and supply is desalination, despite <a href="https://www.abc.net.au/news/2018-03-19/drinking-recycled-water/9546900">strong community support</a> for large-scale recycling. </p>
<p>In Adelaide and Brisbane, wastewater and stormwater are treated and reused only for industry, irrigation and energy production. As the Millennium Drought fades from public memory, state governments have also retreated from attempts to encourage household water tanks.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/more-of-us-are-drinking-recycled-sewage-water-than-most-people-realise-92420">More of us are drinking recycled sewage water than most people realise</a>
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<p>By 2050 as many as <a href="https://www.theguardian.com/australia-news/2018/nov/22/australias-population-forecast-to-hit-30-million-by-2029">10 million extra people</a> may live in Australia’s capital cities. All of them will expect a reliable supply of clean water inside and outside their homes. </p>
<p>Our book shows how governments have historically favoured development of new water sources or desalination over recycling or demand management. These approaches do little to help us learn to use water more wisely in our cities and suburbs. Recycled water, education campaigns and demand management must play a greater role in securing future water supplies.</p><img src="https://counter.theconversation.com/content/188795/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Margaret Cook received receives funding from the Australian Research Council (Discovery Project DP180100807) and this article is based on that research.</span></em></p><p class="fine-print"><em><span>Andrea Gaynor receives funding from the Australian Research Council (Discovery Project DP180100807). She is affiliated with the Beeliar Group: Professors for Environmental Responsibility. </span></em></p><p class="fine-print"><em><span>Lionel Frost receives funding from the Australian Research Council (Discovery Project DP180100807). </span></em></p><p class="fine-print"><em><span>Peter Spearritt received funding from the Australian Research Council (Discovery Project DP180100807).</span></em></p><p class="fine-print"><em><span>Ruth Morgan has received funding for this research from the Australian Research Council (DP180100807). She is also funded by the ARC SR200200322.</span></em></p>Australian politicians have a history of opting for high-cost, high-emissions desalination projects. The Queensland government is still wary of using the largely untapped resource of recycled water.Margaret Cook, Lecturer in History, University of the Sunshine CoastAndrea Gaynor, Professor of History, The University of Western AustraliaLionel Frost, Associate Professor of Economics, Monash UniversityPeter Spearritt, Emeritus Professor, School of Historical and Philosophical Inquiry, The University of QueenslandRuth Morgan, Associate Professor of History, Australian National UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1882582022-08-26T12:49:25Z2022-08-26T12:49:25ZWhy clean, affordable water should not be in the hands of private companies targeting profit – new research<figure><img src="https://images.theconversation.com/files/481204/original/file-20220825-24-1c3orv.jpg?ixlib=rb-1.1.0&rect=52%2C45%2C4966%2C2867&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/hosepipe-being-used-water-garden-summer-2186807005">Shutterstock/Nigel J. Harris</a></span></figcaption></figure><p>England’s water companies have come in for some <a href="https://www.theguardian.com/commentisfree/2022/aug/20/water-company-ceos-industry-political-failure">heavy criticism</a> this summer. An extremely <a href="https://www.metoffice.gov.uk/about-us/press-office/news/weather-and-climate/2022/driest-july-in-england-since-1935">dry July</a> has led to <a href="https://www.theguardian.com/environment/2022/aug/12/drought-declared-england-hosepipe-ban-water-restrictions">drought status</a> being declared in many areas, while 3 billion litres of water <a href="https://www.nao.org.uk/wp-content/uploads/2020/03/Water-supply-and-demand-management.pdf">are lost</a> through leakage every single day. </p>
<p>Those firms have also come under fire for the pollution they cause, with only <a href="https://publications.parliament.uk/pa/cm5802/cmselect/cmenvaud/74/report.html">14% of English rivers</a> meeting “good” ecological status. Increasing sewage discharges into rivers and seas is a serious public health issue, with the Environment Agency <a href="https://www.standard.co.uk/news/uk/environment-agency-investors-water-southern-thames-b1012337.html">calling for prison sentences</a> for those responsible for the most serious incidents. </p>
<p>Meanwhile, shareholders and investors have seen significant returns. In the 12 years to 2021, England’s nine water and sewerage companies paid out an <a href="https://gala.gre.ac.uk/id/eprint/34274/14/34274%20HALL_Water_and_Sewerage_Company_Finances_%28Rev.2%29_2021.pdf">average of £1.6 billion a year</a> in dividends. Directors’ pay too, has soared. The new CEO of Thames Water received a £3.1 million <a href="https://www.theguardian.com/business/2022/aug/15/drought-hits-water-company-chief-executives-paid">“golden hello”</a> when she joined in 2020. </p>
<p>Our <a href="https://www.tandfonline.com/doi/full/10.1080/13563467.2022.2084521">latest research</a> examines the way that private equity investors have come to dominate ownership of England’s water companies – and how they operate with considerably less transparency than publicly listed companies and a more aggressive approach to extracting profit. </p>
<p>These high levels of dividends, directors’ pay (and debt finance, which could make some of the companies increasingly precarious as interest rates rise) are all paid for by water consumers. Many of these customers struggle to pay, and the cost of living crisis will only put them under even more strain. </p>
<p>Overall then, the English water system works through ordinary households funding generous returns to largely unknown shareholders via complex corporate structures often routed via tax havens, simply through their consumption of water. </p>
<p>So what has happened to regulation in all this? In our paper, we argue that the regulatory process – which in England involves three separate agencies responsible for quality, environmental impact, and prices – faces significant challenges in achieving a fair balance between the interests of investors, consumers and the environment. </p>
<p>Water companies motivated by profit need to be given financial incentives to operate in the wider social interest. The prices they are allowed to charge customers are based on estimates of future costs and achieving certain targets concerning water quality, pollution incidents, leakage and consumption. </p>
<p>This can produce bizarre results. For example, the government wants to see water consumption fall from around 140 litres per person per day to 110 litres by 2050. If this happens, water companies will be able to increase prices. Effectively then, we would all end up paying them a reward for achieving our own reduction in consumption. </p>
<h2>Muddying the water</h2>
<p>It all adds up to a very unusual business model. After all, it is not as if an unhappy customer can simply choose to get their water from another source.</p>
<p>And our paper shows that the current regulatory structure is no match for the sophisticated practices of private finance. It faces an unmanageable task. </p>
<p>Efforts to tilt the balance in favour of consumers inevitably impinge on investors, and this meets with resistance. Some <a href="https://nic.org.uk/app/uploads/NIC-Strategic-Investment-Public-Confidence-October-2019.pdf">reports</a> have found a systemic bias toward investors in infrastructure regulation.</p>
<p>No other country has followed the English example, and elsewhere water is largely in the public sector. Paris took its water back <a href="https://iwaponline.com/wp/article-abstract/16/1/197/20125/Discussion-The-remunicipalization-of-Paris-s-water?redirectedFrom=fulltext">into public ownership</a> in 2010 after 25 years of private control. The year after, the unit price of water was cut by 8% as a result of savings due to public management. </p>
<figure class="align-center ">
<img alt="Water pouring out of pipe." src="https://images.theconversation.com/files/481205/original/file-20220825-723-79i9zy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/481205/original/file-20220825-723-79i9zy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/481205/original/file-20220825-723-79i9zy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/481205/original/file-20220825-723-79i9zy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/481205/original/file-20220825-723-79i9zy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/481205/original/file-20220825-723-79i9zy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/481205/original/file-20220825-723-79i9zy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Cash flow.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/water-flow-pipe-sunset-abstract-399659251">Shutterstock/harnchoke punya</a></span>
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<p>Switching to public ownership is not simple, but one <a href="https://gala.gre.ac.uk/id/eprint/31646/3/31646%20LOBINA_et_al_Water_Remunicipalisation_in_Paris_%28PSIRU%29_2021.pdf">recent study</a> suggests it is becoming increasingly popular in Europe. Nor would it be cheap, but in the long run, cost savings are likely with profits reinvested, and public ownership should lead to greater transparency.</p>
<p>The current arrangement is not working. Put simply, it is impossible to mould private profit incentives to meet the public interest in water. As extreme weather events are set to increase, water needs to be in public ownership to ensure that social and environmental outcomes can be prioritised over private profits.</p>
<p>England’s water was privatised with an ideological faith in private sector efficiency. But there is a major policy inconsistency in the heavy reliance on the public sector to steer water companies towards social and environmental goals. After 33 years, the private ownership experiment has failed.</p><img src="https://counter.theconversation.com/content/188258/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kate Bayliss does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Paris successfully took water back into public ownership. There is growing evidence to suggest England should do the same.Kate Bayliss, Research Associate, Department of Economics, SOAS, University of LondonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1881752022-08-05T15:41:25Z2022-08-05T15:41:25ZUK drought: are farmers facing the crop failures of 1976 all over again?<p>July 2022 was the <a href="https://www.metoffice.gov.uk/about-us/press-office/news/weather-and-climate/2022/driest-july-in-england-since-1935">driest July in England</a> since 1935. Combined with record breaking temperatures, we are hearing talk of a drought comparable to the great <a href="https://www.ceh.ac.uk/news-and-media/news/new-publication-1975-76-drought-contemporary-and-retrospective-review">drought of 1976</a>, with fears of disruptions to public water supply and poor crop yields, especially for fruit and vegetables. But <a href="https://www.tandfonline.com/doi/abs/10.1080/02508068508686328">not all droughts are the same</a> and not all farmers are affected by the same type of drought.</p>
<p>To a meteorologist, drought is usually defined as a period of significantly below-average rainfall. However, low rainfall even over a whole season does not necessarily mean the water supply will run low, or that industry or agriculture will suffer, since there could be lots of water already stored in reservoirs and groundwater.</p>
<p>Of course, such reserves are little help for grassland, cereals and other crops that are entirely rain-fed and are badly impacted when we get a dry spring and summer. The past 12 months have been <a href="https://www.metoffice.gov.uk/research/climate/maps-and-data/uk-temperature-rainfall-and-sunshine-anomaly-graphs">particularly dry</a> over much of the UK and since May 2021, only October and February have recorded above-average rainfall. </p>
<p>Things are even worse if combined with the high temperatures and plentiful sunshine we have seen this year, which increases evaporation and depletes soils of the water required for plant growth – a so-called “agricultural drought”.</p>
<p>We have evaluated the combined impact of the low rainfall and hot, sunny weather using <a href="https://www.frontiersin.org/articles/10.3389/fenvs.2020.589871/full">potential soil moisture deficit</a> (PSMD), which is a cumulative measure (in millimetres) of the balance between rainfall input to the soil and potential losses through evaporation and plant transpiration. </p>
<p>When evaporation exceeds rainfall, the soils become drier and the PSMD increases. When it rains, it reduces. Usually, the PSMD starts to increase from late March or early April, peaking in August or September when the soils are at their driest. A high PSMD means that <a href="https://www.fwi.co.uk/arable/crop-management/crops-struggle-with-lack-of-rain-as-drought-fears-intensify">rain-fed crops</a> like cereals and grass, as well as our <a href="https://www.rhs.org.uk/lawns/drought-care">gardens</a>, will suffer.</p>
<p>Using data from weather stations in Cambridge, we estimate the PSMD in 2022 has (so far) behaved very similarly to 1976. The deficit started to increase in early March and has continued to grow through to the end of July. </p>
<p>This is in contrast to the last drought <a href="https://www.frontiersin.org/articles/10.3389/fenvs.2020.589871/full">in 2018</a>, when the spring was wetter and the soil drying was delayed. PSMD currently stands at about 350mm, which is around 50% higher than the average peak between 1981 and 2010. So for farmers that rely solely on rainfall, 2022 looks like it could be as severe an agricultural drought as 1976.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/477434/original/file-20220803-15-wzvjes.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="graph with three similar lines" src="https://images.theconversation.com/files/477434/original/file-20220803-15-wzvjes.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/477434/original/file-20220803-15-wzvjes.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=392&fit=crop&dpr=1 600w, https://images.theconversation.com/files/477434/original/file-20220803-15-wzvjes.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=392&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/477434/original/file-20220803-15-wzvjes.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=392&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/477434/original/file-20220803-15-wzvjes.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=493&fit=crop&dpr=1 754w, https://images.theconversation.com/files/477434/original/file-20220803-15-wzvjes.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=493&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/477434/original/file-20220803-15-wzvjes.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=493&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Potential Soil Moisture Deficit (PSMD) in Cambridge, UK, in 1976, 2018 and 2022.</span>
<span class="attribution"><span class="source">NIAB Cambridge and Cambridge Digital Technology Group</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Irrigated farming might be restricted</h2>
<p>Most grassland and “broadacre” crops like cereals and oilseeds are grown in the UK without irrigation. It is not that they don’t need the water, but that it is financially unattractive to invest in irrigation equipment. </p>
<p>However, to ensure yield and particularly crop quality, much of the UK’s potato, vegetable and fruit crops are given extra water from irrigation during dry periods. Dry soil also means that demand for water for irrigated crops will be higher, competing with reduced available water resources for other sectors. </p>
<p>To the water resources manager, a “hydrological drought” is when the water available in rivers, reservoirs and groundwater is insufficient to meet demand – including demand to maintain a healthy aquatic ecosystem.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/477445/original/file-20220803-11074-6yrn1d.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Field with sprinklers" src="https://images.theconversation.com/files/477445/original/file-20220803-11074-6yrn1d.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/477445/original/file-20220803-11074-6yrn1d.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/477445/original/file-20220803-11074-6yrn1d.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/477445/original/file-20220803-11074-6yrn1d.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/477445/original/file-20220803-11074-6yrn1d.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/477445/original/file-20220803-11074-6yrn1d.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/477445/original/file-20220803-11074-6yrn1d.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Spud soaking: potato is the UK’s main irrigated crop.</span>
<span class="attribution"><span class="source">Giovanni Arrè</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p><a href="https://www.taylorfrancis.com/books/edit/10.1201/9781351114523/achieving-sustainable-cultivation-potatoes-volume-2-stuart-wale">Potatoes</a> account for more than half of the UK’s irrigated area and volume of irrigation water used. In a <a href="http://dspace.lib.cranfield.ac.uk/handle/1826/14122">dry year</a>, we estimate that a hectare of potatoes (just over half a football pitch) needs more than 2 million litres of irrigation water to maintain yield and quality. That is more than 40 litres for every kg of potatoes. </p>
<p>As UK irrigated agriculture and horticulture needs lots of water but is regarded as a non-essential user, irrigated farmers are at risk of mandatory <a href="https://www.legislation.gov.uk/uksi/2006/641/regulation/25/made">restrictions</a> during a drought, with potentially severe financial implications.</p>
<p>Here we see a difference between 1976 – which followed a very dry 1975 – and 2022. The Met Office described rainfall in 2021 as “<a href="https://www.metoffice.gov.uk/binaries/content/assets/metofficegovuk/pdf/weather/learn-about/uk-past-events/summaries/uk_monthly_climate_summary_annual_2021.pdf">unremarkable</a>”. This, together with better water metering and investment in infrastructure to move water from areas of availability to need, means water resources are in a better condition now than they were in 1976.</p>
<p>The maps below show the status of river flows across the country in February 1976 and February 2022. Pinks to reds indicate river flows that were below normal (pink) to exceptionally low (crimson) for the time of year. </p>
<p>So while this year’s dry and hot weather has been similar to 1976 with similar effects on our gardens and farming, last winter finished with water resources that were mostly around normal for the time of year. This means we don’t expect widespread mandatory restrictions on irrigated farms, although some restrictions may be imposed to protect supplies in certain catchments.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/477439/original/file-20220803-24-ymhvrk.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two maps of the UK" src="https://images.theconversation.com/files/477439/original/file-20220803-24-ymhvrk.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/477439/original/file-20220803-24-ymhvrk.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=299&fit=crop&dpr=1 600w, https://images.theconversation.com/files/477439/original/file-20220803-24-ymhvrk.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=299&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/477439/original/file-20220803-24-ymhvrk.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=299&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/477439/original/file-20220803-24-ymhvrk.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=376&fit=crop&dpr=1 754w, https://images.theconversation.com/files/477439/original/file-20220803-24-ymhvrk.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=376&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/477439/original/file-20220803-24-ymhvrk.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=376&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">River flow was much lower in the spring before the 1976 flood (left) compared to 2022.</span>
<span class="attribution"><a class="source" href="https://eip.ceh.ac.uk/hydrology/water-resources/">Data: UK Water Resources Portal</a>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>However, despite the water resources situation not being as severe in 2022 as it was in 1976, demand across all uses needs to be managed to prevent a severe hydrological drought this year. It is also prudent to manage our water resources carefully in the summer of 2022, not only to avoid restrictions this year but also to reduce the risk of more severe restrictions next year if the UK follows this dry summer with a dry winter.</p><img src="https://counter.theconversation.com/content/188175/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tim Hess has received funding from the Natural Environment Research Council, the Biotechnology and Biological Sciences Research Council and the Economic and Social Research Council. He is affiliated with Water and Sanitation for the Urban Poor. </span></em></p><p class="fine-print"><em><span>Ian Holman has previously received funding from the Natural Environment Research Council</span></em></p>Unlike this time, the dry summer of 1976 followed a particularly dry year.Tim Hess, Professor of Water and Food Systems, Cranfield UniversityIan Holman, Professor of Integrated Land and Water Management and Head of the Centre for Water, Environment and Development, Cranfield UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1826402022-05-19T12:49:57Z2022-05-19T12:49:57ZGrim 2022 drought outlook for Western US offers warnings for the future as climate change brings a hotter, thirstier atmosphere<figure><img src="https://images.theconversation.com/files/464126/original/file-20220518-16-7pljn3.jpg?ixlib=rb-1.1.0&rect=0%2C16%2C5576%2C3572&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Farmers in some regions are being encouraged to preserve and establish grasslands that can survive drought and protect the soil.</span> <span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/AquiferDepletionDustBowl/8a21df0f3f4f46c3a513ada5b49c63b7/photo">AP Photo/Mark Rogers</a></span></figcaption></figure><p>Much of the western U.S. has been in the grip of an <a href="https://www.climate.gov/news-features/event-tracker/noaa-led-drought-task-force-concludes-current-southwest-drought-preview">unrelenting drought</a> since early 2020. The dryness has coincided with record-breaking <a href="https://www.theguardian.com/world/2022/may/01/us-new-mexico-drought-wildfire-southwest">wildfires</a>, intense and long-lasting <a href="https://www.worldweatherattribution.org/western-north-american-extreme-heat-virtually-impossible-without-human-caused-climate-change/">heat waves</a>, <a href="https://phys.org/news/2022-04-drought-western-scrambling.html">low stream flows</a> and <a href="https://www.nytimes.com/2022/05/03/climate/lake-powell-mead-water-drought.html">dwindling water supplies in reservoirs</a> that millions of people across the region rely on. </p>
<p>Heading into summer, <a href="https://images.theconversation.com/files/464284/original/file-20220519-11-igtk3o.png">the</a> <a href="https://www.cpc.ncep.noaa.gov/products/expert_assessment/sdo_summary.php">outlook</a> is pretty grim.</p>
<p>One driver of the Western drought has been <a href="https://www.pe.com/2021/09/24/la-nina-is-about-to-take-the-southwest-drought-from-bad-to-worse/">persistent La Niña conditions</a> in the tropical Pacific since the <a href="https://psl.noaa.gov/enso/mei/">summer of 2020</a>. During La Niña, cooler tropical Pacific waters help nudge the jet stream northward. That tends to bring <a href="https://www.climate.gov/news-features/understanding-climate/el-ni%C3%B1o-and-la-ni%C3%B1a-frequently-asked-questions">fewer storms to the southern tier of the U.S.</a> and produce pronounced drought impacts in the Southwest.</p>
<p>The <a href="https://www.nationalgeographic.com/environment/article/the-drought-in-the-western-us-could-last-until-2030">other</a> and perhaps more important part of the story is the <a href="https://thenevadaindependent.com/article/warming-is-making-the-west-thirstier-researchers-say-and-its-stressing-water-supplies-%EF%BF%BC">hotter and thirstier atmosphere, caused by a rapidly warming climate</a>.</p>
<p><iframe id="vepyM" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/vepyM/9/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>As a <a href="https://cires.colorado.edu/researcher/imtiaz-rangwala">climate scientist</a>, I’ve watched how climate change is making drought conditions increasingly worse – particularly in the western and central U.S. The last two years have been more than 2 degrees Fahrenheit (1.1 Celsius) warmer than normal in these regions. Large swaths of the Southwest have been even hotter, with temperatures more than 3 F (1.7 C) higher. <a href="https://www.scientificamerican.com/article/western-megadrought-is-the-worst-in-1-200-years/">Studies suggest the Southwest’s ongoing 20-year drought</a> is the most severe in at least 1,200 years, based on how dry the soils are.</p>
<h2>A hotter atmosphere sucks more moisture from the soil</h2>
<p>A thristier atmosphere tends to extract more water out of the land. It exacerbates <a href="https://www.drought.gov/data-maps-tools/evaporative-stress-index-esi">evaporative stress</a> on the land, particularly when a region is experiencing below-normal precipitation. High evaporative stress can rapidly deplete soil moisture and lead to hotter temperatures, as the <a href="https://coolcalifornia.arb.ca.gov/how-cool-vegetation-works">evaporative cooling effect</a> is diminished. All this creates hydroclimatic stress for plants, causing restricted growth, drying and even death.</p>
<p>As a consequence of a warming climate, the U.S. Southwest has seen an 8% increase in this evaporative demand since the 1980s. This trend is generally <a href="https://cpo.noaa.gov/News/ArtMID/7875/ArticleID/2523/NIDIS-Funded-Project-Finds-That-Evaporative-Demand-Increase-Across-Lower-48-Means-Less-Water-Supplies-Drier-Vegetation-and-Higher-Fire-Risk">happening across other parts of the country</a>.</p>
<p>The <a href="https://www.climate.gov/news-features/feed/evaporative-demand-increase-across-lower-48-means-less-water-supplies-drier">thistier atmosphere</a> is turning what would otherwise be near-normal or moderately dry conditions into droughts that are more severe or extreme. As the climate heats up further, the increasing atmospheric thirst will continue to intensify drought stress, with consequences for water availability, long-lasting and intense heat stress, and large-scale ecosystem transformation.</p>
<p><iframe id="JHSNq" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/JHSNq/6/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>Climate models project ominous prospects of <a href="https://doi.org/10.1073/pnas.2006323117">a more arid climate and more severe droughts</a> in the Southwest and southern Great Plains in the coming decades.</p>
<p>In addition to direct impacts of increasing temperatures on future droughts, these regions are also expected to see <a href="https://doi.org/10.1038/s41561-017-0001-8">fewer storms</a> and <a href="https://doi.org/10.1175/JHM-D-21-0017.1">more days without precipitation</a>. Climate models consistently project a <a href="https://doi.org/10.1038/s41561-017-0001-8">poleward shift in the midlatitude storm tracks</a> during this century as the planet heats up, which is expected to result in fewer storms in the southern tier of the country.</p>
<h2>Expect flash droughts even in wetter areas</h2>
<p>The changing nature of droughts is a concern <a href="https://nca2018.globalchange.gov/">even in parts of the U.S. that are expected to have a net increase</a> in annual precipitation during the 21st century. In a hotter future, because of the high evaporative demand on the land, prolonged periods with weeks to months of below normal precipitation in these areas can lead to significant drought, even if the overall trend is for more precipitation.</p>
<p>Large parts of the northern Plains, for example, have seen precipitation <a href="https://toolkit.climate.gov/regions/northern-great-plains">increase by 10% or more</a> in the last three decades. However, the region is not immune to severe drought conditions in a hotter climate.</p>
<p>At the tail end of what was the <a href="https://www.drought.gov/sites/default/files/2020-07/NorthernPlains_2017DroughtEvolution.pdf">wettest decade</a> on record in the region, the northern Plains experienced <a href="https://www.drought.gov/news/flash-drought-new-reports-examine-2017-northern-plains-drought">an intense flash drought in the summer of 2017</a> that resulted in agricultural losses in excess of $2.6 billion and <a href="https://www.theguardian.com/environment/2017/sep/07/flash-drought-north-dakota-montana-wildfires">wildfires</a> across millions of acres. <a href="https://doi.org/10.1016/B978-0-12-815998-9.00025-7">Record evaporative demand</a> contributed to the severity of the flash drought, in addition to a severe short-term precipitation deficit. A flash drought is a drought that <a href="https://doi.org/10.1175/BAMS-D-17-0149.1">intensifies rapidly over a period of a few weeks</a> and often catches forecasters by surprise. The likelihood of flash droughts that can <a href="https://www.nature.com/articles/s41467-021-26692-z/07/flash-drought-north-dakota-montana-wildfires">cause severe impacts to agriculture and ecosystems and promote large wildfires</a> is expected to <a href="https://doi.org/10.1038/s41467-022-28752-4">increase</a> with a warmer and thirstier atmosphere.</p>
<figure class="align-center ">
<img alt="The wheat field is less than knee high to the farmer, who is wearing jeans, a long sleeve shirt and a cap and looking down at the wheat." src="https://images.theconversation.com/files/464128/original/file-20220518-21-jf2l58.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/464128/original/file-20220518-21-jf2l58.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=421&fit=crop&dpr=1 600w, https://images.theconversation.com/files/464128/original/file-20220518-21-jf2l58.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=421&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/464128/original/file-20220518-21-jf2l58.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=421&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/464128/original/file-20220518-21-jf2l58.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=529&fit=crop&dpr=1 754w, https://images.theconversation.com/files/464128/original/file-20220518-21-jf2l58.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=529&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/464128/original/file-20220518-21-jf2l58.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=529&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">During the 2017 flash drought, a North Dakota farmer stands in a wheat field that should have been twice as high at that point.</span>
<span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/PlainsDrought/6fbb416f8e92416cbf1ea37fef567c9c/photo">AP Photo/Blake Nicholson</a></span>
</figcaption>
</figure>
<p>Flash droughts are also emerging as a growing concern in the Northeast. In 2020, much of New England experienced an <a href="https://pubs.usgs.gov/of/2020/1148/ofr20201148.pdf">extreme hydrologic drought</a>, with low stream flows and groundwater levels and widespread crop losses between May and September. Aided by very warm and dry atmospheric conditions, the drought developed very rapidly over that period from what had been above-normal wet conditions.</p>
<p>As humanity enters a hotter future, prolonged periods of weeks to months of below-normal precipitation are going to be of a greater concern almost everywhere. </p>
<h2>Heading into unfamiliar territory</h2>
<p>Other forms of droughts are also emerging.</p>
<p>Atmospheric heating is causing <a href="https://www.nationalgeographic.com/environment/article/snow-droughts-coming-to-winters-western-us-california-water">snow droughts</a> as more precipitation falls as rain rather than snow and snow melts earlier. Shorter snow seasons and longer growing seasons because of warmer temperatures are <a href="https://doi.org/10.1111/cobi.13727">changing the timing of ecological responses</a>.</p>
<figure class="align-center ">
<img alt="Viewed from an airplane, a long lake snakes through a canyon with a wide white rim around its edge." src="https://images.theconversation.com/files/464127/original/file-20220518-3314-cxkllj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/464127/original/file-20220518-3314-cxkllj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/464127/original/file-20220518-3314-cxkllj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/464127/original/file-20220518-3314-cxkllj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/464127/original/file-20220518-3314-cxkllj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/464127/original/file-20220518-3314-cxkllj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/464127/original/file-20220518-3314-cxkllj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The ‘bathtub ring’ on Lake Powell, one of the nation’s largest reservoirs, attests to its falling water level over two decades of drought in Arizona. The Colorado River reservoir is crucial for water supplies and hydropower.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/the-tall-bleached-bathtub-ring-is-visible-on-the-rocky-news-photo/1325430487">Justin Sullivan/Getty Images</a></span>
</figcaption>
</figure>
<p>Land is <a href="https://doi.org/10.1111/gcb.13224">greening up earlier</a> and causing an earlier loss of water from the land surface through <a href="https://www.usgs.gov/special-topics/water-science-school/science/evapotranspiration-and-water-cycle">evapotranspiration</a> – the loss of water from plants and soil. This could result in drier soils in the latter half of the growing season. As a result, parts of the central and western U.S. could see <a href="https://doi.org/10.1175/JCLI-D-17-0213.1">both increased greening and drying in the future</a> that are seasonally separated across the growing season.</p>
<p>With a rapidly changing climate, we are entering <a href="https://doi.org/10.1016/j.oneear.2020.08.019">unfamiliar territory</a>. The world will need new ways <a href="https://doi.org/10.1016/j.oneear.2020.08.019">to better anticipate future droughts</a> that could transform <a href="https://doi.org/10.1126/science.abj6777">natural</a> and <a href="https://theconversation.com/transformational-change-is-coming-to-how-people-live-on-earth-un-climate-adaptation-report-warns-which-path-will-humanity-choose-177604">human</a> systems.</p>
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Read more:
<a href="https://theconversation.com/hydropowers-future-is-clouded-by-droughts-floods-and-climate-change-its-also-essential-to-the-us-electric-grid-182314">Hydropower's future is clouded by droughts, floods and climate change – it's also essential to the US electric grid</a>
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<img src="https://counter.theconversation.com/content/182640/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Imtiaz Rangwala receives funding from USGS, USDA, NOAA, US Forest Service. He is affiliated with the University of Colorado Boulder, North Central Climate Adaptation Science Center and Western Water Assessment. </span></em></p>La Niña is only part of the problem. The long-term driver of increasing drought – even in areas getting more rainfall overall – is the rapidly warming climate.Imtiaz Rangwala, Research Scientist in Climate, Cooperative Institute for Research in Environmental Sciences, University of Colorado BoulderLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1820122022-05-02T12:37:13Z2022-05-02T12:37:13ZSatellites over the Amazon capture the choking of the ‘house of God’ by the Belo Monte Dam – they can help find solutions, too<figure><img src="https://images.theconversation.com/files/459872/original/file-20220426-12-ce5rr7.jpg?ixlib=rb-1.1.0&rect=110%2C8%2C1886%2C1113&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">NASA's Landsat satellites have been monitoring changes on Earth's landscape for 50 years.</span> <span class="attribution"><a class="source" href="https://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=10812">NASA illustration</a></span></figcaption></figure><p>The Xingu River is revered as the “<a href="https://sites.coloradocollege.edu/indigenoustraditions/sacred-lands/xingu-tribes-and-the-belo-monte-dam/">house of God</a>” by the Indigenous people living along its Volte Grande, or Big Bend, in the Brazilian Amazon. The river is essential to their culture and religion, and a crucial source of fish, transportation and water for trees and plants.</p>
<p>Five years ago, the Big Bend was a broad river valley interwoven with river channels teaming with fish, turtles and other wildlife. Today, as much as 80% of the water flow is gone.</p>
<p>That’s because in late 2015, the massive Belo Monte Dam project began redirecting water from the Xingu River upstream from the Big Bend, channeling it through a canal to a giant new reservoir. The reservoir now powers one of the largest hydropower dams in the world, designed with enough capacity to power around 20 million households, though it has been <a href="https://theconversation.com/this-amazon-dam-is-supposed-to-provide-clean-energy-but-its-destroying-livelihoods-and-unique-species-166773">producing far less</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/459909/original/file-20220426-12-msu0wb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A young person drops off baskets while people wait behind him in a narrow boat holding manioc, an edible root." src="https://images.theconversation.com/files/459909/original/file-20220426-12-msu0wb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/459909/original/file-20220426-12-msu0wb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/459909/original/file-20220426-12-msu0wb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/459909/original/file-20220426-12-msu0wb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/459909/original/file-20220426-12-msu0wb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/459909/original/file-20220426-12-msu0wb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/459909/original/file-20220426-12-msu0wb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Indigenous communities living in the Big Bend region of the Xingu River and its Bacaja tributary rely on the river for food and to transport crops.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/after-harvesting-a-weeks-worth-of-manioc-from-one-of-the-news-photo/470902995?adppopup=true">Taylor Weidman/LightRocket via Getty Images</a></span>
</figcaption>
</figure>
<p>Most of the river’s flow now bypasses the Big Bend, and the Indigenous peoples who live there are watching <a href="https://e360.yale.edu/features/an-amazon-defender-stands-up-for-her-land-and-her-people">their livelihoods</a> and <a href="https://www.loe.org/shows/segments.html?programID=21-P13-00013&segmentID=2">way of life become endangered</a>. Some of the most devastating effects are during the rainy season, when wildlife and trees rely heavily on having high water. The consortium of utilities and mining companies that runs the dam has pushed back on government orders to allow more water to reach the Big Bend, claiming it would <a href="https://www.reuters.com/article/brazil-dam-idCNL1N2IR2M8">cut their generation and profits</a>. The group has argued in the past that there was <a href="https://news.mongabay.com/2021/03/amazons-belo-monte-dam-cuts-xingu-river-flow-85-a-crime-indigenous-say/">no scientific proof</a> that the change in water flow harmed fish or turtles.</p>
<p>There is proof of the Belo Monte Dam project’s impact on the Big Bend, though – from above. Satellite data shows how dramatically the dam has altered the hydrology of the river there.</p>
<p><iframe id="3O4sz" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/3O4sz/7/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<figure>
<iframe frameborder="0" class="juxtapose" width="100%" height="400" src="https://cdn.knightlab.com/libs/juxtapose/latest/embed/index.html?uid=ac448b06-c5a6-11ec-b5bb-6595d9b17862"></iframe>
</figure><figure><figcaption>The front satellite image shows the Big Bend of the Xingu River on May 26, 2000, before the Belo Monte Dam project began. Move the slider to the left to see the same region on July 20, 2017.</figcaption></figure>
<p>The same satellite data can also point to potential solutions and ways that operators of the Belo Monte Dam could revise the dam’s operations to keep both its renewable power and the Xingu River flowing at the most important times of the year.</p>
<p>As <a href="https://scholar.google.com/citations?user=fUbQsaoAAAAJ&hl=en">scientists who work with remote sensing</a>, we believe satellite observations can empower populations around the world who face threats to their resources. The fact that satellite observations of surface water of the Xingu River can be clearly tied to the construction and operation of the Belo Monte Dam offers hope that this kind of knowledge can no longer be hidden.</p>
<h2>50 years of Earth observation</h2>
<p>Satellites have been monitoring changes in Earth’s landscapes for 50 years, ever since the U.S. launched the <a href="https://www.usgs.gov/landsat-missions/landsat-1">first Landsat satellite</a> on July 23, 1972. By piecing together data from the Landsat program and other satellites, scientists can reconstruct historical patterns of change in the landscape and predict current and future trends. They can monitor forest cover, drought, wildfire damage and desert expansion, <a href="https://doi.org/10.1016/j.envsoft.2021.105043">as well as river flows</a> and reservoir operations around the world.</p>
<p>An example of how that data can be used to help threatened communities is the global <a href="http://www.satellitedams.net">Reservoir Assessment Tool</a>, which was <a href="https://doi.org/10.1016/j.envsoft.2021.105043">created by</a> colleagues and one of us at the University of Washington. It monitors how much water is in about 1,600 reservoirs around the world.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/459869/original/file-20220426-14-ssn5d4.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Screenshot of the tool showing a map of Brazil and an example dam's chart of water outflow." src="https://images.theconversation.com/files/459869/original/file-20220426-14-ssn5d4.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/459869/original/file-20220426-14-ssn5d4.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=361&fit=crop&dpr=1 600w, https://images.theconversation.com/files/459869/original/file-20220426-14-ssn5d4.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=361&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/459869/original/file-20220426-14-ssn5d4.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=361&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/459869/original/file-20220426-14-ssn5d4.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=454&fit=crop&dpr=1 754w, https://images.theconversation.com/files/459869/original/file-20220426-14-ssn5d4.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=454&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/459869/original/file-20220426-14-ssn5d4.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=454&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Reservoir Assessment Tool allows communities to track river flow changes caused by nearby dams and locate proposed dams. It currently tracks dams built before 2000.</span>
<span class="attribution"><a class="source" href="http://www.satellitedams.net">University of Washington</a></span>
</figcaption>
</figure>
<p>Dam operators already collect thorough on-site data about water flow, but their datasets are rarely shared with the public. Remote sensing doesn’t face the same restrictions. Making that data public can help hold operators to account for and protect local communities and their rivers.</p>
<h2>How satellites could pressure Belo Monte to share</h2>
<p>Satellite monitoring can provide unprecedented insight into the operations of dams like the Belo Monte and their impact on downstream populations.</p>
<p>Existing satellite data can be used to monitor recent historical behavior of a dam’s operations, track the state of the river and patterns of inflow and outflow at the dam, and even forecast the likely state of the reservoir. Much of that data is easily accessible and free. For example, a tool created for the regional governing body of the Mekong River Commission is empowering communities along the river in Southeast Asia by giving them access to <a href="https://depts.washington.edu/saswe/mekong/">satellite data about water flow at each dam</a> – data that cannot be hidden or modified by those in power.</p>
<p>While estimates based on remote sensing have higher uncertainty than on-site measurements, unfettered access to such information can provide local populations with evidence to argue, in court if necessary, for more water releases.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/GmLjTpix4Uw?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Members of Indigenous groups living in the Big Bend region talk about changes they’ve seen since the dam was built.</span></figcaption>
</figure>
<p>Long-term observations of dams and hydroclimate records show it is possible to <a href="https://doi.org/10.1016/j.jhydrol.2020.125708">revise the standard operating procedures of dams</a> so they allow more water to flow downstream when needed. A compromise with the Belo Monte Dam could ensure that enough water flows to the Xingu’s Big Bend region while also providing hydropower benefits.</p>
<p>By making the impact of the Belo Monte Dam and others like it public to the world, agencies and the general public can put pressure on the dam’s operators and its investors to release more water. Public pressure will become increasingly important, as water disputes in the Amazon are expected to worsen as the planet warms <a href="https://www.cfr.org/in-brief/deforestation-brazils-amazon-has-reached-record-high-whats-being-done">and deforestation continues</a>. Climate change <a href="https://doi.org/10.1038/s41893-020-0492-y">will affect river flow patterns</a> in the Amazon and likely increase droughts, leaving less water during some periods.</p>
<h2>A tool for social justice</h2>
<p>The Amazonian native population has declined, and dams and nearby mining operations, <a href="https://e360.yale.edu/features/an-amazon-defender-stands-up-for-her-land-and-her-people">like those threatening the Xingu’s Big Bend region</a>, play a role. The current Brazilian government under president Jair Bolsonaro has generally sided with <a href="https://www.iwgia.org/en/brazil.html">wealthy landowners and industry over Indigenous peoples</a>, making access to independent data crucial for protecting these communities.</p>
<p>Monitoring dams is a powerful way satellites can make a difference. Nearly two-thirds of Brazil’s electricity comes from <a href="https://www.abradee.org.br/setor-eletrico/visao-geral-do-setor/">more than 200 large and 400-plus small</a> hydropower plants, and <a href="https://news.mongabay.com/2020/10/brazils-amazon-dam-plans-ominous-warnings-of-future-destruction-commentary/">more large dams are expected</a> to be built in the Amazon this decade. Many are in areas with Indigenous populations.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/459955/original/file-20220427-20-c2tqce.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Wide aerial view of Amazon rainforest and the dam under construction." src="https://images.theconversation.com/files/459955/original/file-20220427-20-c2tqce.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/459955/original/file-20220427-20-c2tqce.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/459955/original/file-20220427-20-c2tqce.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/459955/original/file-20220427-20-c2tqce.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/459955/original/file-20220427-20-c2tqce.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/459955/original/file-20220427-20-c2tqce.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/459955/original/file-20220427-20-c2tqce.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Belo Monte Dam’s construction, shown here in 2012, flooded land and changed the river.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/construction-continues-at-the-belo-monte-dam-complex-in-the-news-photo/146390482?adppopup=true">Mario Tama/Getty Images</a></span>
</figcaption>
</figure>
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<p>Remote sensing may not directly solve the problem of social injustice, but it offers the tools needed to recognize the problems and explore solutions. Being able to monitor changes in near-real time and compare them with historical operations can help maintain the checks and balances required for equitable growth.</p>
<p><em>Raaghul Senthilkumar, a former Master’s student at the University of Washington, contributed to this article.</em></p>
<p><em>This article was updated to highlight the 50th anniversary of the Landsat program, on July 23, 2022.</em></p><img src="https://counter.theconversation.com/content/182012/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Faisal Hossain receives funding from NASA. </span></em></p><p class="fine-print"><em><span>Hörður Bragi Helgason, Pritam Das, and Shahzaib Khan do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>When Indigenous peoples lose their river flow to dams, satellite programs like Landsat – which is celebrating its 50th anniversary – can help them fight for their resources.Pritam Das, Graduate Research Assistant, University of WashingtonFaisal Hossain, Professor of Hydrology, University of WashingtonHörður Bragi Helgason, Graduate Research Assistant, University of WashingtonShahzaib Khan, Graduate Research Assistant in Computational Hydrology, University of WashingtonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1765142022-02-07T16:01:12Z2022-02-07T16:01:12ZMountain glaciers may hold less ice than previously thought – here’s what that means for 2 billion downstream water users and sea level rise<figure><img src="https://images.theconversation.com/files/444660/original/file-20220206-27-1x4umu8.jpg?ixlib=rb-1.1.0&rect=106%2C44%2C3628%2C2323&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Mountain glaciers are under threat from global warming.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/in-this-photo-taken-on-may-17-mountaineers-make-their-way-news-photo/962297762">Phunjo Lama/AFP via Getty Images</a></span></figcaption></figure><p><em>Mountain glaciers are essential water sources for nearly a quarter of the global population. But figuring out just how much ice they hold – and how much water will be available as glaciers shrink in a warming world – has been notoriously difficult.</em></p>
<p><em>In a new study, scientists mapped the speed of over 200,000 glaciers to get closer to an answer. They discovered that widely used estimates of glacier ice volume <a href="https://www.nature.com/articles/s41561-021-00885-z">may be off by about 20%</a> in terms of how much Earth’s glaciers outside the Greenland and Antarctic ice sheets could contribute to sea level rise.</em></p>
<p><em><a href="https://faculty-directory.dartmouth.edu/mathieu-morlighem">Mathieu Morlighem</a>, a leader in ice sheet modeling and a coauthor of the study, explains why <a href="https://www.nature.com/articles/s41561-021-00885-z">the new results</a> hold a warning for regions that rely on glaciers’ seasonal meltwater, but barely register in the big picture of rising seas.</em> </p>
<h2>1) If mountain glaciers hold less ice than previously believed, what does that mean for people who depend on glaciers for water?</h2>
<p>Globally, <a href="https://theconversation.com/the-worlds-mountain-water-towers-are-melting-putting-1-9-billion-people-at-risk-128501">almost 2 billion people</a> rely on mountain glaciers and snowpack as their main source of drinking water. Many also rely on glacier water for hydropower generation or agriculture, particularly in the dry season. But the vast majority of glaciers around the world are losing more mass than they gain during the year as the climate warms, and they <a href="https://doi.org/10.1038/s41586-021-03436-z">are slowly disappearing</a>. That will <a href="https://www.ipcc.ch/srocc/chapter/chapter-2/">profoundly affect these populations</a>.</p>
<p>These communities need to know how long their glaciers will continue to provide water and what to expect as the glaciers disappear so they can prepare.</p>
<p>In most places, we found significantly lower total ice volumes than previous estimates indicated.</p>
<p>In the tropical Andes, from Venezuela to northern Chile, for example, we found that the glaciers have about 23% less ice than previously believed. This means downstream populations have less time to adjust to climate change than they may have planned for. </p>
<figure class="align-center ">
<img alt="A herder moves sheep down a road next to a large water pipe with mountains in the background." src="https://images.theconversation.com/files/444748/original/file-20220207-85126-106wv1o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/444748/original/file-20220207-85126-106wv1o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=353&fit=crop&dpr=1 600w, https://images.theconversation.com/files/444748/original/file-20220207-85126-106wv1o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=353&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/444748/original/file-20220207-85126-106wv1o.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=353&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/444748/original/file-20220207-85126-106wv1o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=444&fit=crop&dpr=1 754w, https://images.theconversation.com/files/444748/original/file-20220207-85126-106wv1o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=444&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/444748/original/file-20220207-85126-106wv1o.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=444&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A herder walks beside a water pipe near La Paz, Bolivia. A glacier long relied on for water there is nearly gone.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/local-indigenous-sheep-herder-walks-past-a-water-pipe-at-news-photo/523905156">Tim Clayton/Corbis via Getty Images</a></span>
</figcaption>
</figure>
<p>Even in the Alps, where scientists have a lot of direct ice thickness measurements, we found that the glaciers may have 8% less than previously thought.</p>
<p>The big exception is the Himalayas. We calculated that there may be 37% more ice in these remote mountains than previously estimated. This buys some time for communities that rely on these glaciers, but it does not change the fact that these glaciers are melting with global warming.</p>
<p>Policymakers should look at these new estimates to revise their plans. We do not provide new predictions of the future in this study, but we do provide <a href="https://www.nature.com/articles/s41561-021-00885-z">a better description</a> of what the glaciers and their water supplies look like today.</p>
<p><iframe id="0Qk4G" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/0Qk4G/13/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<h2>2) How do these finding affect estimates of future sea level rise?</h2>
<p>First, it’s important to understand that melting glaciers are only one contributor to sea level rise as the climate warms. About one-third of today’s sea level rise is due to <a href="https://sealevel.nasa.gov/understanding-sea-level/global-sea-level/thermal-expansion">thermal expansion</a> of the ocean – as the ocean warms, water expands and takes up more space. The other two-thirds come from <a href="https://www.climate.gov/news-features/understanding-climate/climate-change-global-sea-level">shrinking mountain glaciers and ice sheets</a>. </p>
<p>We found that if all the glaciers, not including the big ice sheets in Greenland and Antarctica, were to melt entirely, <a href="https://www.nature.com/articles/s41561-021-00885-z">sea level would rise by about 10 inches</a> instead of 13 inches. This may sound like a large difference, considering the size of the ocean, but you have to put things in perspective. A complete disintegration of the Antarctic ice sheet would contribute <a href="https://climate.nasa.gov/news/2749/ramp-up-in-antarctic-ice-loss-speeds-sea-level-rise/">190 feet</a> to sea level and the Greenland ice sheet would contribute <a href="https://www.jpl.nasa.gov/news/nasa-greenland-mission-completes-six-years-of-mapping-unknown-terrain">24 feet</a>.</p>
<p>The 3 inches that we are talking about in this study do not call into question current projections of sea level rise.</p>
<h2>3) Why has it been so hard to figure out the ice volume of glaciers, and what did your study do differently?</h2>
<p>You might be surprised by how much is still unknown about some of the basic characteristics of remote mountain glaciers.</p>
<p>Satellites have transformed our understanding of glaciers since the 1970s, and they provide an increasingly clear picture of <a href="https://www.glims.org/RGI/">glacier locations and surface area</a>. But satellites cannot see “through” the ice. In fact, for 99% of the world’s glaciers, there is no direct measurement of ice thickness. Scientists have spent more time mapping the <a href="https://www.antarcticglaciers.org/glaciers-and-climate/estimating-glacier-contribution-to-sea-level-rise/">Greenland and Antarctica ice sheets</a> and the terrain below, and we have much more detailed volume measurements there. NASA, for example, dedicated an entire airborne mission, <a href="https://www.nasa.gov/mission_pages/icebridge/mission/index.html">Operation IceBridge</a>, to collect ice thickness measurements in Greenland and Antarctica.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/444625/original/file-20220206-501-1ts25eb.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/444625/original/file-20220206-501-1ts25eb.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/444625/original/file-20220206-501-1ts25eb.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=223&fit=crop&dpr=1 600w, https://images.theconversation.com/files/444625/original/file-20220206-501-1ts25eb.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=223&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/444625/original/file-20220206-501-1ts25eb.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=223&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/444625/original/file-20220206-501-1ts25eb.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=280&fit=crop&dpr=1 754w, https://images.theconversation.com/files/444625/original/file-20220206-501-1ts25eb.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=280&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/444625/original/file-20220206-501-1ts25eb.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=280&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The new mapping techniques are more precise, as a comparison of Iceland’s Vatnajökull ice cap shows. The image on the left is the new map.</span>
<span class="attribution"><a class="source" href="https://doi.org/10.1038/s41561-021-00885-z">R. Millan et al., 2022</a></span>
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<p>Scientists have come up with <a href="https://doi.org/10.1038/s41561-019-0300-3">various techniques</a> to <a href="https://doi.org/10.1002/2014RG000470">determine the volume</a> of glaciers, but the uncertainty for remote mountain glaciers has been pretty high.</p>
<p>We did something different compared to previous studies. We used satellite imagery to map the glaciers’ speed. Glacier ice, when it is thick enough, behaves like thick syrup. We can measure how far the ice is moving using two satellite images and map its speed, which goes from a few feet to about 1 mile per year. Mapping the displacement of more than 200,000 glaciers was no easy task, but that created a data set nobody had seen before.</p>
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<a href="https://images.theconversation.com/files/444626/original/file-20220206-17-kwn95c.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/444626/original/file-20220206-17-kwn95c.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/444626/original/file-20220206-17-kwn95c.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=527&fit=crop&dpr=1 600w, https://images.theconversation.com/files/444626/original/file-20220206-17-kwn95c.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=527&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/444626/original/file-20220206-17-kwn95c.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=527&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/444626/original/file-20220206-17-kwn95c.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=663&fit=crop&dpr=1 754w, https://images.theconversation.com/files/444626/original/file-20220206-17-kwn95c.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=663&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/444626/original/file-20220206-17-kwn95c.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=663&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Images show the velocity of glacier ice in regions around the world.</span>
<span class="attribution"><a class="source" href="https://doi.org/10.1038/s41561-021-00885-z">R. Millan et al., 2022</a></span>
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<p>We used this new information of ice speed and simple principles of ice deformation to determine the thickness of the ice at each pixel of these satellite images. In short, the ice speed we observe from space is due to the ice sliding on its bed and also its internal deformation. The internal deformation depends on its surface slope and ice thickness, and the slipperiness of its bed depends on the temperature of the ice at its base, the presence or absence of liquid water, and the nature of the sediments or rocks underneath. Once we could calibrate a relationship between ice speed and sliding, we could calculate ice thickness.</p>
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<p>To map the flow speed of all of these glaciers, we analyzed 800,000 pairs of images collected by satellites from the European Space Agency and NASA.</p>
<p>Of course, as with any indirect method, they are not perfect estimates and they will be further improved as we collect more data. But we have made a lot of progress in reducing the overall uncertainty.</p><img src="https://counter.theconversation.com/content/176514/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mathieu Morlighem receives funding from NASA, NASA and the Heising-Simons Foundation.</span></em></p>Glaciers in North America, Europe and the Andes, in particular, have significantly less ice than people realized.Mathieu Morlighem, Professor of Earth Sciences, Dartmouth CollegeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1732582022-01-09T08:23:14Z2022-01-09T08:23:14ZA deep data dive reveals extent of unequal water provision in Nairobi<figure><img src="https://images.theconversation.com/files/439693/original/file-20220106-23-8by7nu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Women line up to collect water in their buckets in the informal settlement of Kibera in Nairobi.
</span> <span class="attribution"><span class="source">Photo by Wendy Stone/Corbis via Getty Images</span></span></figcaption></figure><p>Many African cities struggle to supply safe, potable water to their residents. One of the main reasons for this is <a href="https://www.bloomsburycollections.com/book/water-and-society-changing-perceptions-of-societal-and-historical-development/ch9-water-and-climate-change">urbanisation</a>; cities’ populations grow rapidly as more people move to them from rural areas. </p>
<p>Another reason, in some regions, is <a href="https://www.bloomsburycollections.com/book/water-and-society-changing-perceptions-of-societal-and-historical-development/ch9-water-and-climate-change">water scarcity</a>.</p>
<p>Researchers have long suspected that informal urban neighbourhoods are lagging behind their formal counterparts when it comes to accessing safe drinking water. But this reality can be obscured when data is aggregated to city scale rather than being examined at a granular, localised level.</p>
<p>Numerous studies have been conducted to examine inequalities in safe water access. Most measure this <a href="https://link.springer.com/article/10.1007%2Fs10668-017-9913-0">access</a> through source type, such as access to tap water. Some have incorporated other dimensions of water service delivery, notably <a href="https://pubs.acs.org/doi/abs/10.1021/es303345p">water quality</a>. However, relatively few studies have examined intra-urban differences in the volumes of water consumed.</p>
<p>In our <a href="https://www.sciencedirect.com/science/article/pii/S019739752100165X">study</a> in the Kenyan capital, Nairobi, we examined patterns of domestic piped water distribution between 1985 and 2018. We used data from Nairobi’s water and sewerage utility using small areas they call “itineraries”. These have an average population of 700. We also examined granular population data from the <a href="https://www.worldpop.org/">WorldPop mapping initiative</a> and we drew on spatial data about the age of different neighbourhoods for the years between 1975 and 2014 from the <a href="https://ghsl.jrc.ec.europa.eu">Global Human Settlement project</a>.</p>
<p>This data allowed us to examine differences between neighbourhoods in sufficient domestic water consumption, cost, and water access. Crucially, we could examine changes over time. The data revealed that newly developed low-income urban neighbourhoods – home to up to a <a href="https://www.sciencedirect.com/science/article/pii/S019739752100165X">third</a> of Nairobi’s population – are not as well serviced as older, wealthier and less densely populated areas. </p>
<p>Our hope is that these findings may influence governance and policy in the water sector. Water supply must be reliable, safe and affordable to everyone who lives in Nairobi.</p>
<h2>Key findings</h2>
<p>The data showed that water sufficiency in Nairobi differs according to several factors. These include the age of a neighbourhood, income level, type of water access and the size of the population per itinerary.</p>
<p>The World Health Organisation <a href="https://www.who.int/publications/i/item/9789240015241">recommends</a> at least 1500 litres of water per individual per month for domestic use. We found that residents in high- and middle- income areas were six and four times more likely to receive 1500 litres. Less densely populated areas were more likely to receive higher volumes of water. </p>
<p>The manner in which people access water differs according to income, too. People in high- and middle- income areas tend to have piped connections in their homes. Those in middle to low and low-income areas were more often getting water from communal taps or water kiosks (water vendors who sell water purchased from the utility company).</p>
<p>We also found that a great deal of water – an average of 3.5 billion litres per month – is being wasted either through burst pipes, theft or irregular meters. This is more than twice the amount of water needed for every one of the city’s residents, across all areas, to access the recommended 1500 litres a month.</p>
<h2>Tackling the problem</h2>
<p>There are three ways to address the spatial inequality of water access in Nairobi: good data to plan water services and tariffs, investing in infrastructure, and governance.</p>
<p>Data on water supply and consumption is key in assessing the gaps in the water distribution process. It can also help to ensure better management of sometimes scarce or limited water supplies. Historically, government data has been poorly stored. </p>
<p>However, there have been positive improvements in this regard as governments increasingly ensure that their data is accessible, electronically stored, complete and consistent. This enables research and future planning. Kenya has digitised the water consumption data and made the water tariff structure publicly available.</p>
<p>Improving water sufficiency will also require the right investments from the government. Growth in city population should be accompanied by investments in infrastructure to support provision of safe water to the population – including proper funding of water utility companies to enhance their performance. Investments should be organised based on residential category and neighbourhood age, with a focus on the groups the data shows are not being well serviced.</p>
<p>Finally, good governance is required to minimise both water losses and social inequalities. There should be a deliberate prioritisation of water supply and infrastructure development in low-income areas, both in newer and older neighbourhoods, and in densely populated areas. This is critical if Kenya is to achieve the water access targets <a href="https://au.int/Agenda2063/popular_version">outlined</a> in the African Union’s Agenda 2063 and the 2030 United Nations’ Sustainable Development <a href="https://sdgs.un.org/goals">Goals</a>.</p><img src="https://counter.theconversation.com/content/173258/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Henry Mutembei receives funding from Kenya Climate Smart Project.</span></em></p><p class="fine-print"><em><span>James Wright receives funding from UK Research and Innovation (UKRI) and has previously received funding from the UK Royal Society, Medical Research Council and Natural Environment Research Council. </span></em></p><p class="fine-print"><em><span>Thumbi Mwangi receives funding from United States Agency for International Development, Wellcome Trust, UK Research and Innovation (UKRI), Kenya National Research Fund and Bill and Melinda Gates Foundation. He is affIliated with the Washington State University, the University of Edinburgh and the University of Nairobi.</span></em></p><p class="fine-print"><em><span>Mutono Nyamai does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The manner in which people access water differs according to income. People in high- and middle- income areas tend to have piped connections in their homes.Mutono Nyamai, PhD candidate, University of NairobiHenry Mutembei, Professor in veterinary reproduction and obstetrics, University of NairobiJames Wright, Professor in Geographic Information science and International Development, University of SouthamptonThumbi Mwangi, Associate professor, Washington State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1628462021-06-17T20:09:32Z2021-06-17T20:09:32ZVictoria’s wild storms show how easily disasters can threaten our water supply<p>The <a href="https://www.news.com.au/technology/environment/thousands-still-without-power-as-residents-tally-storm-damage/news-story/23b32f184f1bd83fadb8ecabaa98dc4d">wild storms</a> that recently raged across eastern Victoria caused major property and environmental damage, and loss of lives. They’ve also triggered serious water contamination incidents. </p>
<p>Yarra Valley Water issued an <a href="https://www.yvw.com.au/do-not-drink-advisory-notice-issued-16-june-updated-230pm">urgent health warning</a> to not to drink tap water — not even if it’s boiled — in three affected suburbs: Kalista, Sherbrooke and The Patch. </p>
<p>So what caused this incident? <a href="https://emergency.vic.gov.au/respond/?=&bbox=145.30466079711914%2C-37.91847196277946%2C145.4670524597168%2C-37.859946717594056&tm=1623821197040#!/warning/16950/moreinfo">Yarra Valley Water says</a> the severe weather led to an equipment failure, with potentially unsafe water entering the drinking water system. </p>
<p>I spoke to the water authority about the nature of the contamination, and they did not provide any more detail. But based on my three decades of experience in the water industry, I can offer some insight into how disasters create contamination crises, and Australia’s vulnerabilities.</p>
<h2>Does boiling water help?</h2>
<p>Despite recent health warnings, it’s worth pointing out that Australia’s water supply is generally safe and reliable, with few exceptions. Still, this is hardly the first time disasters have disrupted water supply, whether from <a href="https://theconversation.com/heavy-rains-are-great-news-for-sydneys-dams-but-they-come-with-a-big-caveat-131668">droughts</a>, storms and floods, <a href="http://www.bom.gov.au/water/about/waterResearch/document/Daniell_and_White_Montpellier_2005.pdf">or bushfires</a>. </p>
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<p>For example, the Black Summer bushfires damaged water supply infrastructure for many communities, such as in Eden and Boydtown on the south coast of New South Wales. The Bega Valley Shire Council issued a <a href="https://begavalley.nsw.gov.au/cp_themes/default/page.asp?p=DOC-QCM-74-68-40">boil water notice</a>, as the loss of electricity stopped chlorinating the water supply, which is needed to maintain safe disinfection levels. </p>
<p>Boil water alerts indicate harmful pathogens may be present in the water, and you <a href="https://theconversation.com/better-boil-ya-billy-when-australian-water-goes-bad-99451">should boil water</a> for <a href="https://www.cdc.gov/healthywater/drinking/travel/backcountry_water_treatment.html">at least one minute</a> to kill them.</p>
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<a href="https://theconversation.com/better-boil-ya-billy-when-australian-water-goes-bad-99451">Better boil ya billy: when Australian water goes bad</a>
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<p>In inland and remote communities, drinking water contamination can be more common and very difficult to resolve. </p>
<p>For example, many remote Western Australian towns have <a href="https://www.abc.net.au/news/2021-06-03/remote-community-water-report/100185414">chronic water quality problems</a>, with drinking water often failing to meet Australian standards. And in 2015, the WA Auditor General <a href="https://audit.wa.gov.au/wp-content/uploads/2015/05/report2015_08-AbServices.pdf">reported</a> the water in many Indigenous communities contains harmful contaminants, such as uranium and nitrates. </p>
<p>The <a href="https://ww2.health.wa.gov.au/Articles/N_R/Nitrate-in-drinking-water">source of this contamination</a> is often naturally occurring chemical compounds in the local geology of ground water supplies. </p>
<p>One of the biggest contamination incidents in Australia occurred in August and September in 1998. A series of extreme wet weather events after a long drought triggered the contamination of Sydney’s drinking water with high levels of protozoan parasites, which can cause serious diseases such as <a href="https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/gastroenteritis-cryptosporidiosis">gastroenteritis or cryptosporidiosis</a>. <a href="https://www.phrp.com.au/wp-content/uploads/2014/10/NB98027.pdf">It resulted in</a> boil water alerts across much of the Sydney metropolitan area.</p>
<p>But what makes this latest incident in Victoria so concerning is that authorities have warned <a href="https://twitter.com/VicGovDH/status/1405352083440558082?s=20">even boiling will not</a> reduce contamination. This suggests contamination may be due to the presence of a harmful chemical, or high levels of sediment particles.</p>
<p>Sediment in water — measured as “<a href="https://www.who.int/water_sanitation_health/publications/turbidity-information-200217.pdf">turbidity</a>” — can be hazardous because these particles can hold other contaminants, or even shield pathogens from disinfection. </p>
<p>Yarra Valley Water’s advice for the affected suburbs is to avoid using water in any cooking, making ice, brushing teeth or mixing baby formula, and for people to take care not to ingest water in the shower or bath. Emergency drinking water is being supplied by Yarra Valley Water in some locations. </p>
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<h2>So why do disasters threaten our drinking water?</h2>
<p>This latest incident is another reminder that our drinking water is vulnerable to disruption from extreme weather. </p>
<p>This is almost certain to continue, and worsen, as the the Bureau of Meterology’s <a href="http://www.bom.gov.au/state-of-the-climate/">State of the Climate 2020</a> report predicts more extreme weather — including drought, heatwaves, bushfires, storms, and floods — in Australia’s future. </p>
<p>As these disasters become more frequent and extreme under climate change, <a href="https://www.climatecouncil.org.au/resources/water-security-report/">impacts on water supplies</a> across Australia are likely to become more destructive. </p>
<p>A good example of how this can unfold was the impact on Canberra’s water supply after the destructive 2003 bushfires. </p>
<p>Fire burned most of the region’s Cotter River catchments, which hold three dams. After fires went out, massive storms eroded the weakened ground, and washed ash, soil and organic debris into the storage reservoirs. <a href="http://www.ecosmagazine.com/?act=view_file&file_id=EC120p8.pdf">It took years</a> for the water supply system to fully recover.</p>
<p>Physical damage to water infrastructure is also a big risk, as modern water supplies are large and complex. For example, a fallen tree could break open the roof of a sealed water storage tank, exposing water to the elements. </p>
<p>Interruptions of electrical supplies after extreme weather are also common, leading to failures of water supply technology. This, for instance, could stop a water pump from operating, or break down the <a href="https://www.industry.nsw.gov.au/water/news/new-water-metering-telemetry-system-now-operational">telemetry system</a> which helps control operations. </p>
<p>As difficult as these hits to Australia’s water security are, and will be in future, it’s even more problematic in the <a href="https://www.unicef.org/stories/water-and-climate-change-10-things-you-should-know">developing world</a>, which may not have the resources to recover. </p>
<h2>How can we withstand these challenges?</h2>
<p>To maintain optimal water quality, we must protect the integrity of water catchments — areas where water is collected by the natural landscape. </p>
<p>For example, <a href="https://www.abc.net.au/news/2021-04-20/vicforests-illegally-logging-in-water-catchments/100079514">damaging logging operations</a> along <a href="https://theconversation.com/logging-must-stop-in-melbournes-biggest-water-supply-catchment-106922">steep slopes</a> in Melbourne’s biggest water catchment threatens to pollute the city’s drinking water because it increases the risk of erosion during storms.</p>
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<a href="https://theconversation.com/logging-must-stop-in-melbournes-biggest-water-supply-catchment-106922">Logging must stop in Melbourne's biggest water supply catchment</a>
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<p>There’s also merit in Australian cities investing in advanced <a href="https://www.circleofblue.org/2014/world/recycled-water-facility-in-australia-offers-lessons-global-drought-planning/">treatment of wastewater</a> for reuse, rather than build infrequently used desalination plants for when there’s drought.</p>
<p>Australia could follow the US state of California which <a href="https://watereuse.org/wp-content/uploads/2019/07/WateReuse-CA-Action-Plan_July-2019_r5-2.pdf">has ambitious targets</a> to reuse more than 60% of its sewage effluent. </p>
<p>And it’s completely safe — Australia has <a href="https://www.waterquality.gov.au/guidelines/recycled-water">developed guidelines</a> to ensure recycled water is treated and managed to operate reliably and protect public health. </p>
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Read more:
<a href="https://theconversation.com/why-does-some-tap-water-taste-weird-94661">Why does some tap water taste weird?</a>
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<p>If you’re concerned about water quality from the tap and haven’t received any alerts, you might just not <a href="https://theconversation.com/why-does-some-tap-water-taste-weird-94661">like its taste</a>. If in doubt, contact you local water supplier. </p>
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<p><em>This story is part of a series The Conversation is running on the nexus between disaster, disadvantage and resilience. It is supported by a philanthropic grant from the Paul Ramsay foundation. You can read the rest of the stories <a href="https://theconversation.com/au/topics/disaster-and-resilience-series-97537">here</a>.</em></p><img src="https://counter.theconversation.com/content/162846/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ian Wright has received funding from industry, local and state government agencies. </span></em></p>Three suburbs in Victoria have been warned against drinking tap water — even if they boil it first.Ian A. Wright, Senior Lecturer in Environmental Science, Western Sydney UniversityLicensed as Creative Commons – attribution, no derivatives.