Last year was extremely wet and sadly flooding impacted many people across Victoria and New South Wales. We sincerely hope the weather is kinder in 2023.
In Australia, we’ve had three consecutive La Niña years of above average rain and these created the conditions for much of the flooding in 2022.
When catchments are saturated, the land has limited capacity to absorb water. Any water the land can’t soak up flows across it and into our river systems. If the maximum carrying capacity of a river is exceeded, the water will rise higher than its banks and flow onto the surrounding areas.
We often associate flooding with disaster and loss but it’s a natural process that’s beneficial to many plants, animals and environments across Australia. When floods occur, they can replenish billabongs and wetlands and are essential to life cycles of many important species of flora and fauna.
Flood water also carries valuable nutrients and minerals that can be deposited in soils which are important for agriculture.
Flooding can be devasting. However, dams can help us regulate river systems, capture floodwater, and allow us to release water in a controlled way that can help mitigate the impacts of floods downstream.
Southern Rural Water manages seven water storages across southern Victoria. Our storages are dams built on a river or creek and hold back water to form a lake behind it.
We manage both gated and fixed crest dams. Fixed crest dams are designed for water to flow over the edge once they reach its full level. This means we have limited ability to control the flow. However, if the storage isn’t full before rain, it can reduce downstream flooding.
Gated dams like Lake Glenmaggie give us more control for flood mitigation. The gates allow us to lower the water level in the dam by releasing water in advance of forecast rain. Doing this helps us reduce the effects of flooding downstream.
We have flood management plans for all our storages that guide our strategy and operations. We use weather, stream flow and catchment data to build complex models. These models help us predict scenarios and make decisions about storage levels and combined with operational considerations, allow us to determine when to release water from our dams in a controlled way.
Three years of above-average rainfall means most of our dams are full. Our job is to balance holding water for customers and releasing water to ensure we protect the dams and the downstream communities. However, we can’t prevent all floods.
We work closely with the Bureau of Meteorology and emergency services to manage floods.
For official flood and emergency warnings, visit the Bureau of Meteorology and for flood warnings go to VicEmergency.