Often, when the global community thinks about the challenges we face in water, the first thought is about the availability of water – adequacy of supply. Drought looms large in the public’s mind, with images of parched fields, cracked earth and muddy remnants of once great rivers.
These mental pictures are amplified in the context of climate change. In many cases this is rightly so, with many of the earliest impacts of climate change being seen in prolonged periods of dry conditions, overall reductions in rainfall, and increasing temperatures leading to greater water loss through evaporation and transpiration. As we know, however, more extreme, less predictable weather conditions mean more than just severe droughts – they include more frequent and intense floods.
The incidence of these floods is not limited to developing nations. In July 2021, multiple European countries were affected by catastrophic floods, causing deaths and widespread damage. From late February to early March 2022, parts of Australia – my home country – were hit by extreme flooding following days of rain, including ‘rain bombs’. Southern Queensland and northern New South Wales each received more than a year’s worth of rainfall in a week.
For the water sector, the impacts are immense. Inundation of sewer pumping stations and sewage spills, loss of power to water treatment plants, contamination of drinking water supplies and scouring, silting and turbidity issues in drinking water catchments.
There are important lessons being learned. From a planning perspective, historic data on rainfall, weather conditions and temperature cannot be relied upon to the same degree as in the past. Dealing with ‘averages’ has always been problematic, especially in places such as Australia, where rainfall has always had a high degree of variability and volatility. Some years ago, a friend of mine commented on a visit to the desert that “the temperature was 40¡C in the shade. . . but there was no shade.” In the same way, average rainfall is a mathematical construct; yearly precipitation can be distributed very unevenly over time and geographically.
It is even clearer now that we must prepare for extreme events. The sector has already established strong capability in diversifying water sources and building resilience into our systems. In southern Queensland, the value of the Gold Coast Desalination Plant was again demonstrated during the recent floods. Initially built to address the risks of insufficient rainfall to meet a growing population, the plant was an important alternative supply when floodwaters impacted water quality in catchments.
In the popular English language fairy tale of ‘Goldilocks and the Three Bears’, a young girl wanders through a forest and into a house inhabited by three bears. While the bears are away, she rather impolitely tests their three beds, sits on their chairs, and eats their porridge. The first bowl of porridge is too hot, the second too cold, but the third is just right. For we water professionals, I fear that the time of a naturally occurring ‘Goldilocks’ water supply – just the right amount falling from the sky or re-charging our aquifers – may be gone. Our challenge is to acknowledge these changes and to adapt. I am confident we are capable of the task.
Tom Mollenkopf, President, IWA