It is widely understood that irrigation development results in deep percolation past the rootzone, which recharges the groundwater. With flood irrigation, watertables often rise at around 0.5 m a year until a new equilibrium is established where the watertable fluctuates from the soil surface to around 3 m deep. A significant part of all irrigation areas in Australia are currently in this condition or approaching such equilibrium. Irrigation areas in southeastern Australia, particularly in