Townley, L.R., Turner, J.V., Barr, A.D., Trefry, M.G., Johnston, C.D., and Nield, S.P. (1996), Groundwater flow patterns near shallow flow-through Lakes, in Wetlands for the Future, INTECOL's V International Wetlands Conference, Perth, 22-28 September, Programme and Abstracts, p.42.

Many lakes on the Swan Coastal Plain near Perth, Western Australia, are predominantly flow-through lakes, which receive groundwater at their upgradient shoreline and discharge lakewater to the regional aquifer at the downgradient shoreline. This paper summarises theoretical modeling results in vertical section, in plan, and also in three dimensions, for an isolated lake in a regional aquifer. Predictions are made of the depth and width of the capture zone of such a lake, including the sensitivity of the capture zone geometry to aquifer flows and recharge. Field results are presented for Nowergup Lake, Lake Jandabup, Lake Mariginiup and Thomsons Lake. Abundances of the natural isotopes deuterium and oxygen-18 and concentrations of chloride are enhanced in the release zones from these lakes, and these observations provide support for model predictions. Interesting findings include the fact that the observed depth of the release zone can in some circumstances be used to estimate a regional scale effective anisotropy ratio. Field data from a vertical section from Lake Pinjar to Lake Nowergup and beyond show that the outflow from one lake can become inflow to another, and modeling confirms that the effective vertical dispersivity in an aquifer may be very small over a length scale of many kilometres. A methodology is presented for computing the capture zones of seven lakes on the Jandakot Mound on the southern Swan Coastal Plain, including the effects of aquifer anisotropy.