Drinking water quality management in bushfire affected catchments

During 2018 and 2019, much of the Australian continent descended into deeper and deeper drought conditions. The impacted areas included almost all of New South Wales, Victoria, southern Queensland and South Australia. As landscapes dried, the risks of uncontrolled bushfires increased. These risks came to a peak during December 2019 and January 2020 with prolonged periods of extreme high temperatures, in some cases coupled with strong winds. During those two months, hundreds of fires burned, many of them out of control for weeks.

Some of the largest and most intense fires burned in important drinking water catchments, including Sydney’s most important catchment, “Warragamba” and catchments for many smaller towns and cities, including Grafton, Coffs Harbour, Nowra and Bega. Immediately following the fires, concerns began to grow regarding potential impacts to drinking water quality. UNSW Global Water Institute (GWI) was quick to respond to these concerns by initiating preparations for a water industry workshop on “Drinking water quality management in bushfire affected catchments”. The workshop took place at the UNSW City Campus on Monday 3 February in collaboration with the NSW Water Directorate, Water Services Association of Australia (WSAA) and the Australian Water Association (AWA).

The workshop began with a series of detailed case studies from water managers who had experienced fires in water catchments, either in the last few weeks or during previous fire seasons. These case studies were presented by representatives of WaterNSW, Tenterfield Shire Council (NSW), Melbourne Water (VIC), TasWater (TAS) and North East Water (VIC). The workshop then proceeded with two panel discussions; the first on “utility trouble shooting” was facilitated by AWA President Carmel Krogh. The second panel discussion was facilities by WSSA Managing Director, Adam Lovell and cantered around a series of “What happens if?” scenarios. Panel participants included representatives of NSW Health, water and catchment management utilities and the Water Sector Services Group mutual aid program.

The timing of this workshop proved to be extremely fortuitous with major rainfall events occurring in many of the affected catchments occurring just five days later, over the weekend of 8/9 February. During this weekend rainfall in excess of 100mm fell in fire-affected water catchments in many parts of Queensland, New South Wales and Victoria. Although little time had been available for additional preparation, an increased level of understanding for how water quality might be impacted was extremely valuable for many of the workshop participants.