Our climate is changing. Although the climate is highly variable, the trend in recent decades has been towards warmer and drier conditions. We’ve seen a decline in cool-season (April to October) rainfall and climate science suggests this is partly the result of increasing levels of atmospheric greenhouse gases.
Most global climate models predict a drier climate future for Gippsland, with an increased frequency of high-pressure weather systems and reduced frequency of low-pressure weather systems and cold fronts that have historically brought us reliable rainfall during the cool season.
This poses a considerable challenge for maintaining reliable water supplies. Rainfall during the cool season provides a greater contribution to runoff and streamflow than at other times of year. Catchment soils are cooler and stay damper, absorbing less rainfall, and trees transpire less moisture to the atmosphere, leaving more of the rain to run off to our rivers and storages. So a reduction in rainfall at this time of year is likely to have an amplified effect on river flows.
We’ve already seen this with a significant reduction in the number of very wet months since 1997, particularly during the cooler time of the year. This is already reducing stream flows in our region, reducing the overall water available to meet the needs of our customers and the environment.