Townley, L.R., and Turner, J.V. (1992), Groundwater flow near shallow lakes: New insights and implications for management, Water Journal, IWWA, 19(6), 40-41.

This report presents the findings of a three-year study funded by the Water Authority of WA, the Environmental Protection Authority of WA and LWRRDC. Although the study focuses on lakes and wetlands of the Swan Coastal Plain near Perth, the results can be applied to a wide range of types of surface water bodies, including rivers, streams, channels, canals and drains.

The results of our research demonstrate the importance of controlling land use activities in areas both upgradient and downgradient of lakes and wetlands. It is well-known that the boundaries of surface water basins and groundwater systems do not coincide. We have shown that most of the larger lakes on the Swan Coastal Plain near Perth receive groundwater which has entered the unconfined aquifer as recharge up to 15 km away, at the top of the regional groundwater mound. When recharge is high, reverse flow regions can form on the downgradient sides of wetlands, thus supplying water in a direction opposite to the average regional flow. The aquifer volume from which groundwater eventually discharges into a water body is knowns as its capture zone. Conversely, the aquifer volume which contains recharge from a water body is known as its release zone.