Which extreme events have the worst affect on water quality? Case studies of regions affected by bushfire, drought and other extreme weather events reveal the rate at which the events occur is the main factor.

This is contrary to initial assumptions that the severity of the event would determine the level of impact.

Consequent weather events combine to negatively effect water quality. For example, following a bushfire phosphorous-heavy ash will cover the ground. Heavy rains soon after will wash the ash into the water catchments.

One of the biggest challenges facing water utilities will be dealing with uncertainty around impacts of climate change. Findings such as these assist with learning and adapting for future management strategies.