Water resources planning in a drying climate in the south-west of Western Australia

The level of water resource development was not at a critically high level when climate change dramatically reduced runoff and recharge in South-west Western Australia. This was because of the state’s relatively low population for its size, a small irrigation industry (mainly based on self-supply groundwater) and the low level of secondary industry. Few resources were heavily over allocated despite the need to significantly de-rate water supply systems. The strong uni-directional drying signal in the south-west of WA has been an advantage in that new water supplies have been developed and/or demands reduced as conditions continued to dry, reinforcing the decisions made. Strong government leadership in adapting to a drying climate in the south-west, through accelerated and alternate water source developments has been extremely successful in mitigating dire impacts, especially in the Perth-Peel region. However, as drying and warming trends continue, there is less opportunity to develop new sources and a need to consider a wider array of sources, especially use in water resource planning. More nuanced planning requires stronger governance settings and increased engagement of stakeholders. A step change in the governance and sophistication of water planning and management could be achieved through new legislation in coming years.