Gnangara Mound

The Gnangara Mound is an area north of Perth, Western Australia where a large mound of sandy soil reaches an elevation of about 60 metres. It stores about 20 cubic kilometres of fresh water, about one hundred times Perth's current annual water usage. It is currently the single most important source of potable water for the city. Together with the Jandakot Mound south of Perth it supplies about 35%-50% of the city's drinking water. However, studies have shown that water levels in the Gnangara Mound have fallen substantially in recent times and this has had a significant impact on nearby groundwater-dependent ecosystems such as wetlands and the Yanchep Caves, and causing acidification of the nearby Lakes Gnangara, Jandabup, Wilgarup and Mariginiup. The remaining mound springs of the Swan Coastal Plain depend on the aquifer and are susceptible to any dramatic change in hydrology. It is widely recognised that sustainability of the Mound as a water resource is under threat. Depletion has been blamed on a combination of climate change and excessive drawing of water.