tag:theconversation.com,2011:/institutions/british-geological-survey-1197/articlesBritish Geological Survey2022-02-01T15:27:53Ztag:theconversation.com,2011:article/1755082022-02-01T15:27:53Z2022-02-01T15:27:53ZCan the UK’s crumbling coasts be saved from erosion?<figure><img src="https://images.theconversation.com/files/443566/original/file-20220131-116292-1qfua0h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Lois GoBe / shutterstock</span></span></figcaption></figure><p>Erosion is constantly reshaping coastlines as land is swept into the sea, sometimes along with buildings and infrastructure. The UK has some of the fastest eroding coastlines in Europe. Of the mainland’s 17,000km of coastline, around <a href="https://www.semanticscholar.org/paper/Impacts-of-climate-change-on-coastal-erosion-Masselink-Russell/f68b65b0a584d2eedcfd7d61aa25bcedec7f1799?p2df">2,900km (17%)</a> is affected by erosion. </p>
<p>Defending this entire coastline would be prohibitively expensive and destroy many of the things we love about the coast – few want to see boulders dumped on their local beach or large stretches of concrete wall. So instead of asking how UK coastlines can be “saved” from erosion, we need to instead consider how they can be managed in a sustainable, holistic way that protects people who live along the coast and allows them to adapt to change.</p>
<p>A number of sewage treatment works, landfill sites and railway lines are already <a href="https://www.ukclimaterisk.org/independent-assessment-ccra3/technical-report/">prone to significant flooding</a>, while seawater can flow over defences during storms, contaminating agricultural land and groundwater supplies. Infrastructure such as these will become more at risk as rising seas cause increased erosion and flooding.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/443770/original/file-20220201-17-manmjw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A house on a clifftop viewed from below" src="https://images.theconversation.com/files/443770/original/file-20220201-17-manmjw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/443770/original/file-20220201-17-manmjw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/443770/original/file-20220201-17-manmjw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/443770/original/file-20220201-17-manmjw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/443770/original/file-20220201-17-manmjw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/443770/original/file-20220201-17-manmjw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/443770/original/file-20220201-17-manmjw.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">Eroding cliffs creep towards a doomed house in Happisburgh, Norfolk.</span>
<span class="attribution"><span class="source">Philip Bird / shutterstock</span></span>
</figcaption>
</figure>
<p>Despite coastline management plans and adaptation measures, such as raising flood defences or managed retreat, the risks are not removed entirely and erosion has continued to <a href="https://www.tandfonline.com/doi/full/10.1080/08920753.2022.2022971?src=">exacerbate hazards</a> like storm surges and landslides. Minimising damage and improving the safety of coastal communities is vitally important.</p>
<h2>Defences v erosion</h2>
<p>Erosion and deposition of sediment are continuously changing the shape of the UK, with the east coast losing several hundred kilometres of land over the past half century. The ever-changing coastline requires maps to be regularly updated using the latest GPS measurements and satellite images. These observations represent a historical snapshot in time, and trying to predict what the coastline will look like in 50 years is difficult as climate change and rising seas are accelerating erosion rates. </p>
<p>Erosion is a major issue, particularly in smaller towns and villages along the UK’s southern and eastern coasts. Barton-on-Sea, a small coastal town in Hampshire, is one such example where residents are worried about their safety due to <a href="https://www.mdpi.com/2073-4441/9/12/905">landslides and high erosion rates</a>. Several meters of frontage have crumbled into the sea and the entire seafront is now classified as highly vulnerable to erosion. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/443754/original/file-20220201-17-qbutns.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Eroding cliff viewed from below" src="https://images.theconversation.com/files/443754/original/file-20220201-17-qbutns.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/443754/original/file-20220201-17-qbutns.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/443754/original/file-20220201-17-qbutns.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/443754/original/file-20220201-17-qbutns.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/443754/original/file-20220201-17-qbutns.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=500&fit=crop&dpr=1 754w, https://images.theconversation.com/files/443754/original/file-20220201-17-qbutns.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=500&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/443754/original/file-20220201-17-qbutns.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=500&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Barton-on-Sea’s eroding cliffs viewed from below.</span>
<span class="attribution"><span class="source">Komali Kantamaneni</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Extensive stretches of <a href="https://www.bbc.co.uk/news/uk-england-humber-53056955">rock armour</a> (large boulders that absorb the force of waves) and <a href="https://climate-adapt.eea.europa.eu/metadata/adaptation-options/groynes-breakwaters-and-artificial-reefs">groynes</a> (structures built from the shore into the sea, designed to trap sediment) were established to provide protection. However, these protections concentrate wave energy in adjacent sites and starve them of sediment leading to accelerated erosion further down the coast. These defences are also unlikely to be effective against stronger storms and higher seas in the future.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/443748/original/file-20220201-13-xvzpdg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Eroding cliffs beside the sea" src="https://images.theconversation.com/files/443748/original/file-20220201-13-xvzpdg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/443748/original/file-20220201-13-xvzpdg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/443748/original/file-20220201-13-xvzpdg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/443748/original/file-20220201-13-xvzpdg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/443748/original/file-20220201-13-xvzpdg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=498&fit=crop&dpr=1 754w, https://images.theconversation.com/files/443748/original/file-20220201-13-xvzpdg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=498&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/443748/original/file-20220201-13-xvzpdg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=498&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">…and the same erosion viewed from the clifftop.</span>
<span class="attribution"><span class="source">Komali Kantamaneni</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Erosion management strategies like this are often divisive, as sediment removed from one section of coastline frequently supplies sand for beaches in another. Beaches provide income from tourism and protection from erosion and flooding. Barton-on-Sea is not the only case where halting erosion in one area has accelerated it in another, and poorly planned coastal defences can have far-reaching detrimental impacts. </p>
<h2>Coastal vulnerability and hotspots</h2>
<p>One of us (Komali Kantamaneni) developed an <a href="https://www.sciencedirect.com/science/article/abs/pii/S0964569117304222">method to compare coastal vulnerability in different areas</a> and identified 11 hotspots where the UK coast was most vulnerable to erosion, and where such erosion would be most economically damaging. These hotspots included towns like Skegness and Great Yarmouth in England and Port Talbot and Aberystwyth in Wales. Together, these areas contain <a href="https://www.sciencedirect.com/science/article/pii/S0964569116301843">£22 billion</a> worth of homes, offices, public buildings, infrastructure and other assets. Flooding, erosion and storm surges in these towns would threaten more than 100,000 people and 50,000 properties.</p>
<p>As coastal areas are increasingly settled, erosion is becoming a bigger risk to society. Towns like Aberystwyth are particularly <a href="https://link.springer.com/article/10.1007/s11069-016-2413-y">vulnerable to strong waves</a>, often several metres high. New developments and redevelopments in the town are exposing more people to the effects of erosion, leading to greater economic losses from flooding and storm damage. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/443767/original/file-20220201-26-1ob6gb2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Map of UK with dots representing vulnerable hotspots." src="https://images.theconversation.com/files/443767/original/file-20220201-26-1ob6gb2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/443767/original/file-20220201-26-1ob6gb2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=766&fit=crop&dpr=1 600w, https://images.theconversation.com/files/443767/original/file-20220201-26-1ob6gb2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=766&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/443767/original/file-20220201-26-1ob6gb2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=766&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/443767/original/file-20220201-26-1ob6gb2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=963&fit=crop&dpr=1 754w, https://images.theconversation.com/files/443767/original/file-20220201-26-1ob6gb2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=963&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/443767/original/file-20220201-26-1ob6gb2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=963&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Economic vulnerability to erosion of selected ‘hotspots’.</span>
<span class="attribution"><span class="source">Komali Kantamaneni</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Sites such as <a href="https://www.confused.com/home-insurance/living-on-the-edge">Hornsea, Camber Sands, Sunderland, Bognor and Withernsea</a> have already lost several hundred meters of coastline, and much of their coastline will crumble into the sea in the next 20 years.</p>
<p>There is, of course, still significant uncertainty about how vulnerable different stretches of the coastline are to erosion. Differing geologies, coastal defences, wave properties and weather make every site respond differently to the effects of climate and land-use change. </p>
<p>Regions vulnerable to erosion need to take steps to reduce the impact of associated hazards like flooding or landslides. Interventions need to be sympathetic to the needs of locals, those down coast and the environment. If we fail to do this, we will encounter ever-increasing societal costs and environmental destruction.</p><img src="https://counter.theconversation.com/content/175508/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Komali Kantamaneni receives funding from British Council and Newton Fund. </span></em></p><p class="fine-print"><em><span><a href="mailto:andr3@bgs.ac.uk">andr3@bgs.ac.uk</a> receives grant funding from UK Research and Innovation, the Natural Environment Research Council and the British Council. </span></em></p><p class="fine-print"><em><span>Luiza C Campos receives funding from the UK Space Agency, Innovate UK, UCL Grand Challenges, and UCL Health of the Public.</span></em></p>Around 17% of the mainland coastline is affected.Komali Kantamaneni, Senior Research Fellow, Faculty of Science and Technology, University of Central LancashireAndrew Barkwith, Principal Numerical Modeller, British Geological SurveyLuiza C Campos, Associate Professor of Environmental Engineering, UCLLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1363152020-05-26T14:13:57Z2020-05-26T14:13:57ZWhy drought programmes in Ethiopia should support communal access to groundwater<figure><img src="https://images.theconversation.com/files/336966/original/file-20200522-153920-xdlaem.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A communal hand pump in Ethiopia. </span> <span class="attribution"><span class="source">Unicef Ethiopia/Flickr</span></span></figcaption></figure><p>Like many countries in east Africa, Ethiopia is <a href="https://www.ifrc.org/Global/Case%20studies/Disasters/cs-ethiopia.pdf">highly vulnerable</a> to drought. Since 1965, Ethiopia <a href="https://www.mdpi.com/2073-4441/11/12/2571">has experienced</a> 15 severe droughts affecting more than 65 million people and causing serious economic damage.</p>
<p>Most recently, in 2015 and 2016, Ethiopia suffered a harsh drought which forced more than 10 million people to rely on <a href="https://www.sciencedirect.com/science/article/abs/pii/S0012825218303519">emergency aid</a> due to crop and water supply failures. </p>
<p>In dispersed rural communities, such as those found in Ethiopia, water supply is highly decentralised. Communities often rely on a number of small communal sources where people collect water. These could be hand-pumps, springs, hand-dug-wells, or motorised pumps in boreholes. </p>
<p>Hand-pumps are installed on boreholes or wells, often by the government or NGOs, and usually tap into groundwater at depths of between 15 to 50 metres. In other areas, motorised boreholes are used to access groundwater hundreds of metres deep and are powered using solar or diesel generators.</p>
<p>Communal sources are often <a href="https://iopscience.iop.org/article/10.1088/1748-9326/ab35be">managed and maintained by communities</a>. So ensuring continuous access to water supplies during drought can be challenging because communities often lack the capacity to repair problems.</p>
<p>What usually happens during a drought is that the focus of intervention programmes is on <a href="https://ngwa.onlinelibrary.wiley.com/doi/full/10.1111/j.1745-6584.2009.00558.x">building more water supply infrastructure</a>. For example; drilling more boreholes and digging more wells. </p>
<p>In a <a href="https://www.nature.com/articles/s41467-020-14839-3#ref-CR4">new study</a> we wanted to know what the most reliable and accessible water source types were for communities during drought. We used data that was collected by UNICEF monitoring teams during the drought in 2015 and 2016. </p>
<p>We found that communal hand-pumped boreholes and motorised boreholes were what communities accessed the most – roughly 400,000 people, about half of the number of people in the study, used them. The others relied on springs, hand-dug wells and open sources, such as rivers. A small number of people relied on emergency water trucking. Hand-pumped boreholes were also associated with the shortest travel times for water collection.</p>
<p>My colleagues and I therefore argue that it’s best for projects to support communities in the use of pre-existing boreholes – particularly hand-pumped boreholes. This is because so many people already rely on them and because they access water that is stored underground and <a href="https://www.nature.com/articles/s41586-019-1441-7">resilient to</a> changes in climate.</p>
<p>Neglecting existing communal water supplies risks leaving many of the most vulnerable and remote communities unserved. In addition, evidence shows that creating new water sources during drought <a href="https://iwaponline.com/washdev/article-abstract/7/4/601/38059/Life-cycle-cost-analysis-of-water-supply?redirectedFrom=fulltext">takes time</a> and can leave additional management and cost burdens on communities, or the local government, when the drought ends. </p>
<p>It’s crucial that the government ensures the boreholes are properly monitored and repaired if they break down. </p>
<h2>Monitoring sources</h2>
<p>During the drought, monitoring teams – set up by UNICEF as part of an emergency intervention – were deployed for three months to monitor the status and performance of different water source types.</p>
<p>The teams collected data about whether sources worked, how many people used them, the amount of time spent collecting water and how much water was collected. We used the data to see how different water points performed.</p>
<p>Monitoring teams used a <a href="https://akvo.org/">mobile phone app</a> which allowed information to be passed around very quickly. This meant more boreholes worked because maintenance teams were able to quickly respond and prioritise repairs.</p>
<p>By fixing boreholes, many more users had access to water. In the case of hand-pumps, it meant travel times to collect water were reduced. The ability of communities to access multiple safe groundwater sources also helped to reduce pressures on individual water sources.</p>
<h2>Supporting hand-pumps</h2>
<p>Our study highlights the importance of hand-pumped and motorised boreholes for ensuring continued access to water during drought. However, we found that while hand-pumps were quickly fixed, repairs for motorised boreholes <a href="https://www.nature.com/articles/s41467-020-14839-3#ref-CR4">were slower</a>. This is because more complex technologies are harder to repair and the skills required are often in short supply. </p>
<p>Our results also suggest caution is required as the rural water supply sector plans for the future. Under the Sustainable Development Goals, communal water sources – such as hand-pumps – are not classified as safely managed and could be neglected for more complex technologies, including on-plot piped water supplies. But, in a similar way to the motorised boreholes in our study, the pipes and pumps used in such systems may break down more often and could take longer to repair, increasing drought vulnerability in areas where there is a lack of financial resources and where it is challenging to find adequate skills for maintenance and repair. </p>
<p>There is already <a href="https://www.sciencedirect.com/science/article/pii/S0043135419300703">evidence</a>, albeit from Vietnam, that poorer households have lower rates of access to piped water supplies than higher income households. Thus, without continued investment in basic communal sources, such as hand-pumps, poorer households may be forced to return to hand-dug wells, springs and surface water sources that offer little <a href="https://www.nature.com/articles/s41467-020-14839-3#ref-CR4">resilience to drought</a> and are <a href="https://iopscience.iop.org/article/10.1088/1748-9326/ab282f">more vulnerable to contamination</a>.</p>
<p>Ensuring communities are able to access multiple safe groundwater water sources, primarily via hand-pumped boreholes but also motorised boreholes, supported by real-time source monitoring and responsive and proactive maintenance and repair, is a reliable way to ensure continued access to water during drought.</p><img src="https://counter.theconversation.com/content/136315/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Donald John MacAllister receives funding from UKRI, NERC and BGS. He is affiliated with the Geological Society, London</span></em></p><p class="fine-print"><em><span>Alan MacDonald receives funding from UKRI, NERC and BGS. He is affiliated with the International Association of Hydrogeologists and the Geological Society, London.</span></em></p><p class="fine-print"><em><span>Seifu Kebede Gurmessa 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>Neglecting existing communal water supplies risks leaving many of the most vulnerable and remote communities unserved.Donald John MacAllister, International Development Hydrogeologist, British Geological SurveyAlan MacDonald, Professor, British Geological SurveySeifu Kebede Gurmessa, Professor of Hydrology, University of KwaZulu-NatalLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/934552018-04-23T14:09:47Z2018-04-23T14:09:47ZAncient Amazonians lived sustainably – and this matters for conservation today<figure><img src="https://images.theconversation.com/files/215584/original/file-20180419-163962-nb0roe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption"></span> <span class="attribution"><span class="source">Ammit Jack / shutterstock</span></span></figcaption></figure><p>Our colleague, the archaeologist Santiago Rivas, recently made a remarkable discovery. On a small plateau above the outskirts of Iquitos, a town in the northern Peruvian Amazon, he found a layer in the soil which contained small pieces of ceramic pottery, that were around 1,800-years-old. Digging deeper, he found another layer of soil, this time containing pottery that was about 2,500 years old.</p>
<p>This is the archaeological site at Quistococha which has been occupied for at least the past 3,000 years. The pottery fragments are beautifully decorated, sometimes with subtle geometric scratch marks or boldly painted with bright red patterns. Not all of the fragments are small: erosion revealed the rim of a large cooking pot that would have been 40cm across when it was intact. Large pots were supported on an open fire by “elephant feet”: small clay pot rests also found in the archaeological layers.</p>
<p>As a place for people to live, Quistococha would have had many advantages. It is located on a terrace above a fertile floodplain of the Amazon which is ideal for growing maize, while the surrounding palm swamp provides fruits and fibres. Just below the terrace, fresh water flows out of a spring.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/215763/original/file-20180420-75093-130hd4r.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/215763/original/file-20180420-75093-130hd4r.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/215763/original/file-20180420-75093-130hd4r.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/215763/original/file-20180420-75093-130hd4r.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/215763/original/file-20180420-75093-130hd4r.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/215763/original/file-20180420-75093-130hd4r.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/215763/original/file-20180420-75093-130hd4r.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/215763/original/file-20180420-75093-130hd4r.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Pottery found at Quistococha.</span>
<span class="attribution"><span class="source">Katherine Roucoux</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Researchers know that indigenous communities have had profound and complex relationships with Amazonian forest landscapes for thousands of years. However, it is still far from clear just how much deforestation took place before European colonisation in the 16th century. </p>
<p>Quistococha is an ideal place to search for answers – and we recently published a <a href="https://onlinelibrary.wiley.com/doi/abs/10.1002/jqs.3019">research article</a> based on our work there. The site has an unusually good record of past environmental change thanks to a nearby floodplain lake and swamp. These preserve the remains of plants that grew there, and the charcoal from fires lit by people – both in the prehistoric period as well as during the expansion of Iquitos over the past two centuries. This combination allowed us to explore the relationship between ancient people and the extent of the surrounding forest.</p>
<p>Charcoal in the sediment core from the nearby lake – an indicator of fire use – was abundant from about 2,500 years ago until the 1800s: people were, therefore, continuously present at that time. However fossil pollen from smaller trees that make up “secondary forest” growing on deforested land only became abundant over the past 150 years, when the nearby city expanded. Prior to that, for thousands of years, indigenous communities apparently had little impact on forest cover.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/215764/original/file-20180420-99367-xyr52q.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/215764/original/file-20180420-99367-xyr52q.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/215764/original/file-20180420-99367-xyr52q.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/215764/original/file-20180420-99367-xyr52q.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/215764/original/file-20180420-99367-xyr52q.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/215764/original/file-20180420-99367-xyr52q.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/215764/original/file-20180420-99367-xyr52q.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/215764/original/file-20180420-99367-xyr52q.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">One of the authors, Tom Kelly, working on Lake Quistococha.</span>
<span class="attribution"><span class="source">Katherine Roucoux</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Such new knowledge about ancient Amazonians is highly relevant for conservation today. For indigenous groups it provides historical context to their fight for land rights and recognition. Studies like ours also show that traditional uses of the landscape should be valued highly, and that Amazonian communities can support themselves without extensive deforestation. This philosophy is the basis for the work of our partners, the <a href="http://www.iiap.org.pe/">Instituto de Investigaciones de la Amazonia Peruana</a> (IIAP), which promotes sustainable management of these floodplain forests. Last but not least, these discoveries are an opportunity to engage with the expanding urban populations of Amazonia: an important voice in the decision-making process.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/213896/original/file-20180409-114105-1axe2af.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/213896/original/file-20180409-114105-1axe2af.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/213896/original/file-20180409-114105-1axe2af.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/213896/original/file-20180409-114105-1axe2af.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/213896/original/file-20180409-114105-1axe2af.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/213896/original/file-20180409-114105-1axe2af.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/213896/original/file-20180409-114105-1axe2af.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/213896/original/file-20180409-114105-1axe2af.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">Iquitos, the largest city in the world with no road connection.</span>
<span class="attribution"><span class="source">Jess Kraft / www.shutterstock.com</span></span>
</figcaption>
</figure>
<p>Iquitos is the largest city in the world not connected to a national road network. Recently, the Peruvian Congress has declared an ambitious range of <a href="https://www.theguardian.com/world/2018/jan/22/peru-passes-law-allowing-roads-through-pristine-amazon-rainforest">road building projects in Amazonia</a> as national priorities. The planned connection between Iquitos and the rest of Peru promises lower prices for food and other imports.</p>
<p>But activists who warn of the adverse consequences of poorly planned development are struggling to be heard. The new road would represent a “first-cut” <a href="https://theconversation.com/how-peru-excludes-indigenous-voices-in-its-quest-to-develop-the-amazon-91449">through indigenous territories</a> and the most diverse and carbon-rich forests of Amazonia. And as these are issues of low importance to the urban majority, the only way to challenge it would be by engaging city dwellers in debates about the implications of future transport networks and of other options for land use.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/215918/original/file-20180423-133881-ort8dh.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/215918/original/file-20180423-133881-ort8dh.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/215918/original/file-20180423-133881-ort8dh.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/215918/original/file-20180423-133881-ort8dh.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/215918/original/file-20180423-133881-ort8dh.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/215918/original/file-20180423-133881-ort8dh.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/215918/original/file-20180423-133881-ort8dh.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/215918/original/file-20180423-133881-ort8dh.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Quistococha beach…not a stereotypical Amazon rainforest scene.</span>
<span class="attribution"><span class="source">Katharine Roucoux</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Locals and tourists alike throng to Quistococha on hot weekends to swim in the lake and relax in waterside cafes. Above and in sight of all of them, but now silent, there is a site that records thousands of years of humans living in a continuously forested landscape. The landscape and the stories it tells are an opportunity to reflect on how we might choose to continue the relationship between people and forests in the future.</p><img src="https://counter.theconversation.com/content/93455/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Timothy Baker receives funding from the Natural Environment Research Council (UK), the Gordon and Betty Moore Foundation (USA) and the Leverhulme Trust (UK).</span></em></p><p class="fine-print"><em><span>Ian Lawson receives funding from the Natural Environment Research Council (UK)</span></em></p><p class="fine-print"><em><span>Katherine Roucoux receives funding from the Natural Environment Research Council (UK)</span></em></p><p class="fine-print"><em><span>Thomas Kelly receives funding from the Natural Environment Research Council (UK). </span></em></p>Indigenous communities lived in the Amazon for thousands of years without chopping down their forests.Timothy Baker, Associate Professor of Tropical Ecology and Conservation, University of LeedsIan Lawson, Senior Lecturer, University of St AndrewsKatherine Roucoux, Lecturer in Physical GeographyThomas Kelly, Aqueous chemist, British Geological SurveyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/871322017-11-10T12:19:35Z2017-11-10T12:19:35ZIs Iceland’s tallest volcano awakening?<figure><img src="https://images.theconversation.com/files/193948/original/file-20171109-27169-17p0ma8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Öræfajökull. </span> <span class="attribution"><span class="source">Dave McGarvie</span>, <span class="license">Author provided</span></span></figcaption></figure><blockquote>
<p>Two women and a boy took refuge on the roof … but it was carried away by the deluge of water, and as far as the eye could reach, the three unfortunate persons were seen clinging to the roof. One of the women was afterwards found among the mud of the jökulhlaup [Icelandic term for meltwater flood], but burnt, and as it were parboild; her body was so damaged and tender, but it could scarcely be touched.</p>
</blockquote>
<p>This is an <a href="http://utgafa.ni.is/Acta-Naturalia-Islandica/Acta-Naturalia-Islandica-II-2.pdf">eyewitness account</a> of three fatalities during the last eruption (1727) of Iceland’s highest volcano, Öræfajökull. It was a relatively small eruption. The previous eruption in 1362, however, remains Iceland’s largest explosive eruption since the island was settled about 1,100 years ago. </p>
<p>This time, thick deposits of pumice and ash (also known as tephra) covered the volcano, while <a href="http://utgafa.ni.is/Acta-Naturalia-Islandica/Acta-Naturalia-Islandica-II-2.pdf">sailors at the time reported</a> pumice floating “in such masses that ships could hardly make their way through it”. Ash from the 1362 eruption <a href="http://www.bgs.ac.uk/research/volcanoes/ashInBritishIsles.html">has been found</a> in Greenland and western Europe recently.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/193947/original/file-20171109-27161-11ttiwq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/193947/original/file-20171109-27161-11ttiwq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/193947/original/file-20171109-27161-11ttiwq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/193947/original/file-20171109-27161-11ttiwq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/193947/original/file-20171109-27161-11ttiwq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=425&fit=crop&dpr=1 754w, https://images.theconversation.com/files/193947/original/file-20171109-27161-11ttiwq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=425&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/193947/original/file-20171109-27161-11ttiwq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=425&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Destructive meltwater floods from both the 1362 and 1727 eruptions travelled down these valley glaciers.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Since June 2017, there have been “swarms” of small earthquakes in the region. Earthquakes are rare at Öræfajökull, so these have <a href="https://en.vedur.is/about-imo/news/new-seismic-stations-installed-around-oraefajokull">prompted meetings</a> between locals, scientists and civil protection authorities. The unusual activity may indicate a reawakening of Öræfajökull, so it is timely to review previous eruptions and the potential effects of a future eruption. </p>
<p>Towering over 2km above coastal plains, Öræfajökull is a majestic sight. Its upper half is covered in ice that feeds valley glaciers that can be easily accessed. Tourists and filmmakers love it. </p>
<p>We first studied the volcano in 2001-2002. Our two <a href="http://www.vmsg.org.uk/events/abstracts/2015_norwich.pdf">main findings</a> were that it has a variety of eruption styles and a surprising abundance of lavas known as <a href="https://flexiblelearning.auckland.ac.nz/rocks_minerals/rocks/rhyolite.html">rhyolites</a>. We know that this can erupt very explosively – as it did in 1362. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/193829/original/file-20171108-14205-1d1qd69.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/193829/original/file-20171108-14205-1d1qd69.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=408&fit=crop&dpr=1 600w, https://images.theconversation.com/files/193829/original/file-20171108-14205-1d1qd69.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=408&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/193829/original/file-20171108-14205-1d1qd69.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=408&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/193829/original/file-20171108-14205-1d1qd69.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=512&fit=crop&dpr=1 754w, https://images.theconversation.com/files/193829/original/file-20171108-14205-1d1qd69.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=512&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/193829/original/file-20171108-14205-1d1qd69.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=512&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">These glacier-scoured cliffs contain a surprising abundance of old evolved lavas.</span>
<span class="attribution"><span class="source">Image courtesy of Snaevarr Guðmundsson.</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>To better understand the 1362 eruption, <a href="http://www.vmsg.org.uk/events/abstracts/2015_norwich.pdf">we have also mapped</a> deposits preserved on the volcano. We found that this explosive eruption was surprisingly variable. It was not just a simple plume that gets gradually weaker, as is common at other volcanoes such as Hekla. </p>
<p>The eruption started by depositing a tephra blanket from a relatively low plume. Next, sticky ash/hail carpeted the volcano. Then the main phase of the eruption began with <a href="https://volcanoes.usgs.gov/vhp/pyroclastic_flows.html">pyroclastic flows</a> (fast-moving current of hot gas and volcanic matter) racing down the flanks, before a tall plume was established and rained huge pumices down on the land while ash clouds drifted away. As the eruption ended, its explosive energy fluctuated rapidly. </p>
<p>The main implication of our study is that explosive eruptions at Öræfajökull can be complicated. The most powerful phase with the highest plume and widest ash dispersal was probably short-lived (lasting from a few hours to a few days), but there were other stages before and after it with varying degrees of explosivity.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/193831/original/file-20171108-14182-1n0rk8m.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/193831/original/file-20171108-14182-1n0rk8m.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/193831/original/file-20171108-14182-1n0rk8m.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/193831/original/file-20171108-14182-1n0rk8m.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/193831/original/file-20171108-14182-1n0rk8m.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/193831/original/file-20171108-14182-1n0rk8m.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/193831/original/file-20171108-14182-1n0rk8m.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Deposits. The prominent pale grey layer (with a hole on the right) is the first sizeable pyroclastic flow deposit.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Locally, the eruption was devastating. Rich farmland at the foot of the volcano was covered by thick tephra deposits and swept by pyroclastic flows. The area was abandoned and renamed “Öræfi” (wasteland). Originally called Hnappafellsjökull, the volcano was renamed Öræfajökull.</p>
<p>What of the inhabitants – did they perish or escape? Three crucial pieces of evidence come from excavations of abandoned farms. Buildings had collapsed prior to the tephra fall and, despite evidence of prosperity, virtually nothing valuable was left behind. Also, no corpses were found. Conclusion? Inhabitants of these farms realised they were in danger, packed their belongings, and left. Large earthquakes then destroyed the buildings before the eruption started. </p>
<h2>Air travel</h2>
<p>The Icelandic volcano Eyjafjallajökull erupted in 2010, causing a lot of problems to air travel across Europe. Would a repeat of the 1362 eruption cause Eyjafjallajökull 2010-style disruption? No, it would not.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/193834/original/file-20171108-14182-av0l40.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/193834/original/file-20171108-14182-av0l40.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/193834/original/file-20171108-14182-av0l40.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/193834/original/file-20171108-14182-av0l40.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/193834/original/file-20171108-14182-av0l40.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/193834/original/file-20171108-14182-av0l40.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/193834/original/file-20171108-14182-av0l40.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Excavation of farm buildings abandoned immediately prior to the 1362 eruption.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Eyjafjallajökull caused so much disruption because the eruption lasted for weeks, with the wind often blowing towards Europe, and because aircraft attempted to “<a href="https://all-geo.org/volcan01010/2014/02/a-history-of-ash-clouds-and-aviation/">avoid all ash</a>”. Since then, improvements to volcanic ash cloud detection and simulation have been made. These, combined with revised procedures at the regulators and airlines, allow planes to fly where low concentrations of ash may be present. For example, the <a href="https://all-geo.org/volcan01010/2013/07/grimsvotn-2011-in-uk-part-2-aviation/">Grímsvötn 2011 eruption</a>, which produced twice as much tephra as the Eyjafjallajökull 2010 eruption in one tenth of the time, caused just 1% of the flight cancellations.</p>
<p>A repeat of the 1362 eruption would disperse ash widely, but our results suggest this stage would be short-lived. This is just one scenario. Others, such as the eruption of lava beneath the ice, may be longer lasting but any disruption would be more localised. </p>
<h2>Local impact</h2>
<p>It’s important to be prepared. Any buildings in the paths of floods would be destroyed. There are farming communities in the area but these have learned from the 1727 eruption and have relocated their farms from the glacier outlets. Before the small 1727 eruption there were earthquake shocks that terrified the people, which suggests that big earthquakes might provide warning of the next eruption and allow time for evacuation. </p>
<p>One of the biggest concerns would be the large number of tourists in the area – especially in summer. The nearby <a href="https://en.wikipedia.org/wiki/Skaftafell">visitor centre of Skaftafell</a> is the seventh most popular tourist destination in Iceland. However, Skaftafell lies outside the flood pathways of both the 1362 and 1727 eruptions – and so it is probably safe from floods.</p>
<p>It’s impossible to estimate exactly when Öræfajökull will next erupt. She may just be turning over in her sleep, soon to return to quiet slumber. Icelandic scientists recently installed additional earthquake monitoring equipment: with their acknowledged expertise in eruption monitoring they will provide the <a href="http://en.vedur.is">best possible information</a> should Öræfajökull fully awaken.</p><img src="https://counter.theconversation.com/content/87132/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dr John A Stevenson received funding from The Scottish Government and Marie Curie Actions via a Royal Society of Edinburgh Personal Research Fellowship. </span></em></p><p class="fine-print"><em><span>Peter Nicholls has received funding from NERC.</span></em></p><p class="fine-print"><em><span>Dave McGarvie 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 saga of Öræfajökull suggests we should take small earthquakes in the region seriously.Dave McGarvie, Senior lecturer, The Open UniversityJohn A Stevenson, Senior Software Developer, British Geological SurveyPeter Nicholls, PhD candidate in volcanology, The Open UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/172962013-08-21T13:54:03Z2013-08-21T13:54:03ZWater supplies may struggle to cope with fracking demands<figure><img src="https://images.theconversation.com/files/29684/original/ck94mg73-1377092950.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Fracking would exacerbate problems with low water levels in reservoirs.</span> <span class="attribution"><span class="source">John Giles/PA</span></span></figcaption></figure><p>The drilling and hydraulic fracturing (fracking) of wells for oil or gas is a well-established technique and requires large quantities of water. During the initial drilling of the well, water is needed for drilling fluids to maintain pressure, cool the drilling head, and remove drill cuttings. A further volume of water is then needed to frack each well.</p>
<p>These large amounts of water, anywhere <a href="http://pubs.acs.org/doi/pdf/10.1021/es903811p">between 7 and 38 million litres</a> (7,000-38,000m<sup>3</sup> ), are typically obtained from nearby surface waters such as rivers or lakes or pumped from groundwater. The environment local to the well would determine where the water is sourced, but once used it is not returned directly to the environment as it is contaminated with <a href="http://elements.geoscienceworld.org/content/7/3/181.abstract">chemicals and sediments</a> from the fracking process. </p>
<p>In areas of the world that are short of water, the sheer volume of water consumed during hydraulic fracturing could make shale gas production <a href="http://www.worldwatch.org/files/pdf/Worldwatch%20Gas%20Paper%20April%202010.pdf">costly and unsustainable</a>. Using scarce water supplies could lead to potentially serious affects on local communities, agriculture and ecosystems, as appears to be the case in <a href="http://www.theguardian.com/environment/2013/aug/11/texas-tragedy-ample-oil-no-water">Texas</a>.</p>
<p>How much water is needed varies greatly, and depends on the depth of the well, the length of horizontal drill, the number of fracking stages and the geology. Estimates of typical water use for shale exploitation provided by the industry in the US for some of the major shale gas fields are shown in the table below (figures drawn from the <a href="http://www.epa.gov/hfstudy/09_Mantell_-_Reuse_508.pdf">EPA</a> and <a href="http://www.cuadrillaresources.com/protecting-our-environment/water/water-sourcing">Cuadrilla</a>). A value is also shown for the Cuadrilla well on the <a href="https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/226874/BGS_DECC_BowlandShaleGasReport_MAIN_REPORT.pdf">Bowland Shale</a> at Preese Hall near Blackpool, Lancashire (but bear in mind that this lower figure comes from a single exploratory well that has not been repeatedly fracked for commercial production).</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/29604/original/nzw5sc3q-1377013313.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/29604/original/nzw5sc3q-1377013313.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=220&fit=crop&dpr=1 600w, https://images.theconversation.com/files/29604/original/nzw5sc3q-1377013313.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=220&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/29604/original/nzw5sc3q-1377013313.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=220&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/29604/original/nzw5sc3q-1377013313.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=276&fit=crop&dpr=1 754w, https://images.theconversation.com/files/29604/original/nzw5sc3q-1377013313.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=276&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/29604/original/nzw5sc3q-1377013313.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=276&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Estimated water requirements per well for drilling and fracturing in different shale gas fields in the US and UK.</span>
</figcaption>
</figure>
<p>So what would be the impact on water supplies in Britain if substantial commercial shale gas drilling got underway? We don’t yet know how rapidly the industry could expand but assuming they could drill 100 wells a year, and using the range of values taken from experience in the US as a guide, the water demand would be between 1.5-2.4 million m<sup>3</sup> a year. </p>
<p>Compared to, for example, the licensed annual water abstraction in England and Wales of <a href="http://cdn.environment-agency.gov.uk/geho1111bvep-e-e.pdf">12,600 million m<sup>3</sup></a>, this is small beer. But it needs to be seen in the context of how much water is needed and available across different areas of the country. In many parts of the south and east of England, water resources are already stressed due to over-abstraction from reservoirs and underground aquifers. Just how vulnerable water resources can be to drought can be seen by the imposition of so-called “hose-pipe bans”, most recently the widespread <a href="http://www.bbc.co.uk/news/uk-17340844">water use restrictions</a> in the (ironically, very wet) summer of 2012.</p>
<p>In the UK, water abstraction is regulated. If no controls on water use were in place, substantial commercial fracking would have a detrimental impact on groundwater and surface water levels, and stream flow rate. Because drillers would need to draw this water in a relatively short period of time to use while drilling, the rapid extraction of water during periods of low stream flow rate could affect fish and other aquatic life due to the waters’ increased temperature and low oxygen concentration. Public water supply and water for agriculture could also be affected. </p>
<p>Of course, if drillers set up better practices for <a href="http://grist.org/news/exxonmobil-subsidiary-with-arm-twisted-behind-back-agrees-to-treat-fracking-wastewater">recycling and re-using fracking fluids</a> the demand on water supplies would be lessened. Potentially even seawater could be used for coastal sites. The industry has responsibility for its wastewater which would normally be treated to prevent any detrimental effect on the environment.</p>
<p>The current increase in climate variability, with drier winters and summers, is putting stress on water resources. But the regulatory framework in the UK is very different from that in the US during their development of shale gas. Many government bodies, such as DECC and Defra have responsibility for regulating shale gas exploration. The Environment Agency, and the equivalent agencies in Scotland, Wales and Northern Ireland, regulate water abstraction by granting licences to draw water, and permits to discharge wastewater to protect our rivers, lakes, and aquifers.</p>
<p>Uncontrolled development and rapid expansion of shale oil and gas drilling would lead to pressure on water supply in some parts of the country. Drillers, regulators and water companies will have to work together to ensure that this nascent industry develops in a way that does not lead to unacceptable shortages. Drawing water would only be allowed where it is deemed sustainable and balanced with human and environmental needs. But further droughts in the UK will undoubtedly represent another challenge that any UK shale gas industry must meet.</p><img src="https://counter.theconversation.com/content/17296/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Marianne Stuart 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 drilling and hydraulic fracturing (fracking) of wells for oil or gas is a well-established technique and requires large quantities of water. During the initial drilling of the well, water is needed…Marianne Stuart, Team Leader Groundwater Protection, British Geological SurveyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/172442013-08-20T05:42:19Z2013-08-20T05:42:19ZExplainer: what are sinkholes?<figure><img src="https://images.theconversation.com/files/29541/original/nmymv9ns-1376921870.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Sinkholes can have a sinking effect on house prices.</span> <span class="attribution"><span class="source">BGS</span></span></figcaption></figure><p>Sinkholes seem to be popping up everywhere this year. March saw the tragic death of <a href="http://www.bbc.co.uk/news/world-us-canada-21646227">Jeff Bush</a> in Seffner, Florida, when his bedroom collapsed into a sinkhole below his house. The same month saw the disappearance - thankfully only temporary - of the golfer <a href="http://www.dailymail.co.uk/news/article-2292176/Mark-Mihal-sinkhole-15-ft-sinkhole-swallows-golfer-St-Louis-course-rescued-friends.html">Mark Mihal</a> into the ground at Waterloo, Illinois. And in August the <a href="http://www.dailymail.co.uk/news/article-2389900/Clermont-sinkhole-Families-flee-terror-Florida-villa-dramatically-ccollapses-near-Disney-World.html">spectacular collapse of holiday apartments</a> at the Summer Bay Resort in Florida.</p>
<p>Sinkholes are natural phenomena, they occur all the time, but can be adversely influenced by human activity. Also called <a href="https://www.bgs.ac.uk/mendips/caveskarst/karst_3.htm">dolines</a>, sinkholes are caused when soluble rocks below ground, including limestone, gypsum and salt, dissolve to form <a href="http://www.bgs.ac.uk/caves/">cave systems</a> and cavities. A sinkhole is formed when these cavities collapse, or where covering materials such as sand, silt or clay funnel into the cavities, causing a collapse of the surface.</p>
<p>The caves may be drained and dry, but the most problematic cases are those that are water-filled and where water is also present in the soil and rocks covering them. A water-saturated mixture of sand, silt or clay can behave rather like quicksand, and becomes very mobile and capable of flowing into the the underlying cave system. It was this sort of water-saturated material that Mr Bush was unfortunate enough to fall into.</p>
<p>Several things can trigger sinkholes. The simple process of gradual dissolution can eventually form a sinkhole, but heavy rain or surface flooding, leaking drainage pipes, or burst <a href="http://pubs.usgs.gov/circ/circ1182/pdf/15WCFlorida.pdf">irrigation mains</a> can initiate the collapse of normally stable cavities, especially those in shallow rocks near the surface. Even the act of emptying a swimming pool has been a documented cause of a sinkhole. In Florida, soft fruit farmers counter potential frost damage to crops by irrigation from automated sprinklers fed from local wells. After several cold days, this additional draw can cause the water levels in the rock to drop considerably triggering sinkholes; one prolonged cold snap in Florida resulted in <a href="http://pubs.usgs.gov/circ/circ1182/pdf/15WCFlorida.pdf">80 sinkholes in a small area</a>. Much of Florida has a sinkhole problem and new developments such as the Summer Bay Resort are built around small lakes or ponds present in sinkholes. As a result, it is not surprising that buildings are commonly affected.</p>
<p>While not as badly affected as Florida, the UK has its <a href="http://www.bgs.ac.uk/science/landUseAndDevelopment/shallow_geohazards/dissolvableRocks.html">fair share of sinkholes</a> and problems associated with them. Sinkhole damage over chalk (a form of limestone) in Bromley caused the <a href="http://news.bbc.co.uk/1/hi/england/london/4915618.stm">demolition of three houses</a> and temporary closure of the main railway line. In Ripon, the dissolution of gypsum causes <a href="http://www.bgs.ac.uk/caves/developmentInRipon.html">abundant sinkholes</a> and resulted in the spectacular <a href="http://www.bgs.ac.uk/caves/gypsum.html">collapse of four garages</a> with damage to a nearby house. A sinkhole may even have been Lewis Carroll’s <a href="http://www.bgs.ac.uk/caves/alice_in_wonderland.html">inspiration</a> for Alice in Wonderland. Sinkholes over <a href="http://www.bgs.ac.uk/caves/limestone.html">limestone</a> are common, but mainly affect areas of open countryside. Overall, the type of damage caused by sinkholes is very similar to that caused by the collapse of shallow mines, but a similar feature caused by mining is more commonly called a crown-hole.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/29544/original/6h5sdht4-1376923530.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/29544/original/6h5sdht4-1376923530.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=927&fit=crop&dpr=1 600w, https://images.theconversation.com/files/29544/original/6h5sdht4-1376923530.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=927&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/29544/original/6h5sdht4-1376923530.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=927&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/29544/original/6h5sdht4-1376923530.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1165&fit=crop&dpr=1 754w, https://images.theconversation.com/files/29544/original/6h5sdht4-1376923530.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1165&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/29544/original/6h5sdht4-1376923530.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1165&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Distribution of soluble rocks in the UK.</span>
<span class="attribution"><span class="source">BGS</span></span>
</figcaption>
</figure>
<p>The hazards associated with sinkholes can largely be mitigated by appropriate planning, ground investigation (with geophysics and boreholes), appropriate design and proper maintenance of infrastructure such as drains and services. Care is required when installing any structures that could affect the local groundwater flow including <a href="http://www.susdrain.org/delivering-suds/using-suds/suds-components/infiltration/soakaways.html">soakaways</a> <a href="http://www.bgs.ac.uk/suds/">SUDs – sustainable drainage systems</a> - and open loop ground source heat pumps. In most places on soluble rocks these may be impractical.</p>
<p>More information about sinkhole hazards in the UK can be found at <a href="http://www.bgs.ac.uk/caves">www.bgs.ac.uk/caves</a></p><img src="https://counter.theconversation.com/content/17244/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Anthony Cooper receives funding from the Natural Environment Research Council (NERC) that has supported the research which forms the basis of the work described here.</span></em></p>Sinkholes seem to be popping up everywhere this year. March saw the tragic death of Jeff Bush in Seffner, Florida, when his bedroom collapsed into a sinkhole below his house. The same month saw the disappearance…Anthony Cooper, Karst Geohazard Specialist, British Geological SurveyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/143762013-05-17T14:24:02Z2013-05-17T14:24:02ZMexico’s smoking giant El Popo lights up again<figure><img src="https://images.theconversation.com/files/24082/original/7q743s97-1368798536.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">And you think your neighbours are bad: millions live alongside active volcanoes.</span> <span class="attribution"><span class="source">Smithsonian Institute Global Volcanism Program</span></span></figcaption></figure><p>The Popocatepetl volcano in Mexico is throwing out <a href="http://www.bbc.co.uk/news/world-latin-america-22535495">plumes of smoke and ash</a>, an eruption that threatens the one million inhabitants of the towns and villages nearby. Mexico City, the world’s third largest city of 21 million people, is only 25 miles away. Earthquakes and ash-falls have occurred regularly since Popocatepetl burst into life again in 1994 after 50 years’ silence, raising the question of how to live alongside these difficult, smouldering neighbours.</p>
<p>Many volcanically active areas are densely populated, with the potential for disaster. When Mount Vesuvius in southern Italy erupted in 79AD, pyroclastic flows of ash and gas and ash-fall devastated the towns of <a href="http://www.britishmuseum.org/whats_on/exhibitions/pompeii_and_herculaneum.aspx">Herculaneum and Pompeii</a>, killing around 16,000 people. Today, Mount Vesuvius is only five miles from Naples, a city of almost four million people. Indonesia is the world’s most volcanically active country, with 76 historically active volcanoes in a country of 238 million people. In October 2010, Merapi volcano on the island of Java erupted, ejecting ash 40,000ft into the atmosphere and killing more than 190 people.</p>
<p>Vulcanologists working at observatories continuously monitor the volcano’s “vital signs” looking for any changes which may pre-empt an eruption. Magma moving through the earth can cause small earthquakes, and the volcano expands in size as it fills with lava. The Merapi eruption could have killed hundreds of thousands of people, but the warning signs were detected and 370,000 people were evacuated.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/24078/original/kjf6hdxh-1368796659.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/24078/original/kjf6hdxh-1368796659.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=359&fit=crop&dpr=1 600w, https://images.theconversation.com/files/24078/original/kjf6hdxh-1368796659.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=359&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/24078/original/kjf6hdxh-1368796659.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=359&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/24078/original/kjf6hdxh-1368796659.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=451&fit=crop&dpr=1 754w, https://images.theconversation.com/files/24078/original/kjf6hdxh-1368796659.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=451&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/24078/original/kjf6hdxh-1368796659.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=451&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A problem for millions of people that live around them, volcanoes amaze and terrify in equal measure.</span>
<span class="attribution"><span class="source">Smithsonian Institution Global Volcanism Program</span></span>
</figcaption>
</figure>
<p>The field of volcanology is moving away from studying the why and how of volcanoes towards hazard mitigation and risk analysis. Volcanologists cannot prevent or even accurately predict an eruption, but we can provide early warning of an eruption, plot and map areas safe from lava flow, and help develop evacuation plans.</p>
<p>At any one time there are around 30 eruptions going on worldwide. Mount Etna in Italy has erupted 13 times this year, most recently a few weeks ago. The eruption of <a href="http://edition.cnn.com/2013/05/15/us/alaska-volcanoes/index.html">Cleveland</a> in Alaska put Californian air traffic control on high alert, and five climbers were killed by a <a href="http://www.bbc.co.uk/news/world-asia-22430378">sudden eruption</a> of Mayon in the Philippines this week.</p>
<p>Volcano observatories worldwide use the international aviation colour code system (green, yellow, orange, red). There are around 30 eruptions at any time worldwide (red), and up to 100 or more in a state of unrest (yellow). But as only a few episodes of detected unrest lead to an eruption, it’s quite common for a volcano to scale from a quiet, normal state, to active and then back again without eruption.</p>
<p>So trying to make local people believe “their” volcano could harm them can be one of the most difficult tasks facing vulcanologists. For example, when asked about Popocatepetl earlier this week, a nearby resident said the volcano took care of them and sent them water. Others visit the volcano every year to ask for rain for their crops. When last evacuated in May 2012 they had belongings stolen from their homes, and after all this the volcano didn’t erupt anyway. Why should they believe it will this time? </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/24083/original/37s8hfbm-1368799585.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/24083/original/37s8hfbm-1368799585.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/24083/original/37s8hfbm-1368799585.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/24083/original/37s8hfbm-1368799585.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/24083/original/37s8hfbm-1368799585.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/24083/original/37s8hfbm-1368799585.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/24083/original/37s8hfbm-1368799585.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The town of Plymouth on the island of Montserrat, completely destroyed by volcano in 1995.</span>
<span class="attribution"><span class="source">Julia Crummy</span></span>
</figcaption>
</figure>
<p>Volcanic eruptions threaten not only the local population but can affect people worldwide. Despite living in a country without volcanoes, residents in the UK felt the effects of the 2010 eruption of <a href="http://blogs.telegraph.co.uk/news/geoffreylean/100035164/theres-bigger-trouble-ahead-from-icelandic-volcanoes-as-the-world-heats-up-scientists-warn/">Ejyafjallajökull</a> in Iceland, as ash clouds drifted across northern Europe, grounding flights and costing the aviation industry millions of pounds. In 1600, the vast amount of ash thrown into the atmosphere by the eruption of <a href="http://www.volcano.si.edu/world/volcano.cfm?vnum=1504-03=">Huaynaputina</a> in Peru caused famines in Northern Europe and Russia that killed millions after crops failed.</p>
<p>On the other hand, Japan, Iceland and New Zealand have harnessed their volcanoes as heat engines providing geothermal energy. Geothermal energy accounts for 66% of Iceland’s energy generation.</p>
<p>Volcanic eruptions are an incredible display of nature’s force. They can be devastating, but they tell much about the planet we live on, and we have even learnt to harness their power. As the human population grows, so does vulcanologists’ responsibility to equip local residents with the knowledge that may save their lives</p><img src="https://counter.theconversation.com/content/14376/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Julia Crummy 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 Popocatepetl volcano in Mexico is throwing out plumes of smoke and ash, an eruption that threatens the one million inhabitants of the towns and villages nearby. Mexico City, the world’s third largest…Julia Crummy, Volcanologist, British Geological SurveyLicensed as Creative Commons – attribution, no derivatives.