Surface water is found on the surface of land, such as in a stream, river, lake or wetland. Surface water is replenished by rain and when groundwater seeps to the surface. It is lost through evaporation, seepage into the ground, use by plants and animals, runoff into the ocean and use by humans for living, agriculture and industry.
Surface water is a highly valued asset in the region. The Inman and South Para rivers are among the largest watercourses. The region’s surface water systems are mainly seasonal, flowing in response to rainfall events, and drain into Gulf St Vincent.
Why surface water is important
Surface water is essential to life and livelihoods in the region. It provides important water sources for natural ecosystems and for human consumption, agriculture and industries. It is also important for aesthetic, recreational and cultural reasons.
Use of surface water
The main uses of surface water in the region are for domestic consumption and agriculture. In a median year the greater Adelaide area sources an average of 60 per cent of its 200 gigalitres of domestic water from the Mount Lofty Ranges area, called the ‘watershed’. There are also many farm dams in the region.
To ensure surface water is used sustainably, some resources are protected by prescription and a water allocation plan that details how the resources can be used. These plans are developed together with the local community.
Managing surface water
Ensuring the quality of surface water in the Mount Lofty Ranges watershed is challenging. The high level of private ownership increases the demand of catchment surface water sources and greatly increases risks to water quality, resulting in extensive and costly water treatment as part of the mains water supply system.