THE City of Swan has three Gnangara mound sites, which are being monitored in response to groundwater use, declining groundwater levels and climate change.
A spokesman for Water Minister Dave Kelly said the sites – one in Melaleuca Park and the other two in the Lexia wetlands – were groundwater dependent wetlands.
One is in Melaleuca Park and the other two in the Lexia wetlands.
All three sites are conservation category wetlands and Bush Forever sites.
Edith Cowan University, which has been monitoring Gnangara mound sites for 22 years has just been appointed through a competitive process managed by the Department of Water and Environmental Regulation to conduct wetland vegetation and macroinvertebrate and water quality studies on the mound again this year.
Professor Pierre Horwitz from the university’s Centre for Ecosystem Management said water quality and the fauna at each wetland were monitored.
Water Minister Dave Kelly said robust science was required to manage the important groundwater resource sustainably.
Mr Kelly said the McGowan Government was serious about taking action to support Perth’s lakes and wetlands suffering from reduced rainfall.
“Since this assessment work started over two decades ago, climate change has reduced the average winter rainfall by around 25 per cent of the long-term average over that time,’’ he said.
“For this reason, we have given the greenlight for further groundwater replenishment to support the use of this system for public water supply and we are working with water users to be more water efficient.”
The Gnangara groundwater system is Perth’s biggest and most reliable fresh water resource and provides almost half of metropolitan area’s water supply.
The system also supports Perth’s natural lakes and wetlands which are some of the most biologically diverse and ecologically important areas on the Swan coastal plain.
Surface waters in many of the wetlands supported by the Gnangara groundwater system have declined during the past 30 years, and ongoing assessment helps target management responses.
Responses to declining water levels so far include reducing the amount of groundwater abstracted for public water supply, changing abstraction patterns to limit take from sensitive areas that affect wetlands and locating groundwater replenishment sites.
Information from the ecological monitoring and investigation is an important component of the Department of Water and Environmental Regulation’s reporting to the Office of Environmental Protection Authority on the status of key groundwater dependent ecosystems.
By Anita McInnes