Drainage in the region around Perth removes more water than all the bores in the superficial aquifer in the same area. Back to Top Managing Perth's groundwater There are two considerations in the management of groundwater - quantity and quality. We want to extract water from the aquifers to meet our needs for a good quality affordable water supply, and to ensure that our houses are dry and agricultural lands are not waterlogged. At the same time, we need to ensure that our natural environment is protected with enough water to maintain trees, streams and rivers, lakes and wetlands. In recent times we have come to understand that too much water can equally be a problem for wetlands, with rising water tables in some areas resulting in the death of lakeside trees, and seasonal lakes being turned into permanent ones resulting in the loss of animals which are specialised to survive in lakes which dry out each year.
Water quality is also important for our health and the environment.
The location and slow movement of groundwater makes it very difficult to remove pollution once it has occurred, so protection and prevention is the best strategy to maintain groundwater quality. Reducing the number of septic tanks in the Metropolitan area, and avoiding development, especially industrial development, over important sources of groundwater are two of the important approaches used. In areas close to the coast and the Swan River estuary, the fresh superficial groundwater overlies a wedge of salty water extending up to a kilometer inland. Excessive pumping from bores in these areas can increase the size of the salt water wedge at the expense of the fresh water, so that the bores start to pump salty water. Once this occurs it can take decades with no extraction before the system can recover.