2008 Joint Annual Meeting (5-9 Oct. 2008): Effect of Lakebed Properties on Aquifer-Lake-Climate Interactions In Semi-Arid Environments and Shallow Saline Lakes In the Nebraska Sand Hills

Water fluxes between shallow lakes and aquifer across the lake beds have been extensively studied in North America and Australia using groundwater models. It is generally accepted that the structure and dynamics of these fluxes determine salinity of the lakes and, partially, of the adjacent groundwater. However, applications of this concept are few because these models require multiple parameters, while hydrogeological data necessary for delineating salinity patterns are scarce. Sensitivity analyses of these parameters are also lacking.

We extend the Zlotnik–Olaguera (2007) lake-aquifer model that considered aquifer anisotropy, flow geometry, and regional flow by including lakebed properties in the groundwater model. Sensitivity analysis shows that previous studies underestimate the importance of lakebed properties that strongly influence lake equilibrium with climate, and more specifically, annual evaporation and precipitation. Incorporating lakebed properties and climate data in the generalized lake-aquifer model at an instrumented site at Alkali Lake provides internally consistent results for lake water budget and salinity. This approach has promise in applications to a system of numerous lakes in the largest vegetated dune field in the Western Hemisphere, the Nebraska Sand Hills.