ForewordJames Cameron Chief Executive Officer National Water Commission March 2012 Groundwater makes up about 17 per cent of Australia’s currently accessible water resources and up to 30 per cent of our water consumption in particular regions. However, this valuable resource is neither understood nor managed as well as it needs to be if it is to be sustained. Continuing water scarcity and climate change are placing pressure on Australia’s groundwater reserves and the security of supply. These ‘hidden’ reserves are increasingly being tapped to supplement surface water supplies. In fact, much of our groundwater is connected to surface water, with consequent impacts on stream flows, aquifer recharge, groundwater–dependent ecosystems, and water quality. Groundwater quality also requires careful management. Risks include uncontrolled urban and industrial discharges, the cross-contamination of aquifers, and seawater intrusion into heavily used coastal aquifers.