Townley, L.R., Turner, J.V., Barr, A.D., Trefry, M.G., Wright, K.D., Gailitis, V., Harris, C.J., and Johnston, C.D. (1993), Interaction between lakes, wetlands and aquifers: Final Report to Land and Water Resources Research and Development Corporation, CSIRO Division of Water Resources, Consultancy Report 93/11, 7pp.

A sequence of dry years in the late 1970s caused a decline in groundwater levels in the Perth region, restrictions on water use and an increased awareness of the role of shallow groundwater in maintaining water levels in many lakes and wetlands. There are literally thousands of wetlands near Perth, of which hundreds are classified as lakes or sumplands, that are either permanently or seasonally wet. One of the major issues concerning lakes and wetlands is that of water level management. Another major issue is that of lake water quality and the role of capture zones or buffer zones in protecting water quality. At the time this Project was proposed, a technical issue of interest was the scientific basis for the methods already being used by the Water Authority of Western Australia to incorporate lakes and wetlands in computer simulation models of regional groundwater flow.

The objectives of this Project were as follows:

1. to understand fully the hydrological behaviour of shallow lakes in steady and transient flow situations by a careful sequence of numerical experiments in two and three dimensions. This will result in the definition of an upstream "capture zone", in which all groundwater flow and any groundwater pollution will eventually pass through the body of the lake; it will also define the zone downstream of a lake in which water quality is influenced by a shallow lake;
2. to validate predictions of lake-aquifer interaction using physical, hydrogeological, chemical and stable isotopic measurements in the field;
3. to calibrate two-dimensional plan models of aquifer flow against three-dimensional local models of shallow lakes, in order to determine effective transmissivities in the vicinity of lakes for use in plan models. This will allow the use of simpler two-dimensional models in further studies of lake-aquifer management strategies; and
4. to investigate and make recommendations on management issues such as the rates of solute and nutrient transport into shallow lakes, possible strategies to reduce the impact of pollution upgradient of a wetland, pumping strategies in the vicinity of wetlands to reduce the effects on lake water levels and strategies for artificial maintenance of lake levels.