Simulation of flow from an aquifer to a partially penetrating trench

Construction of the Tennessee-Tombigbee Waterway in northeast Mississippi will involve dewatering as much as 46 m of an unconfined aquifer near the Tennessee Valley divide. Dewatering by trenching is one of the proposed methods. Methods of calculating effects of dewatering by trenching have been heretofore limited to situations where ideal conditions such as isotropic aquifers and fully penetrating trenches occur. In order to study the effects of trenching on the water table in the more complicated hydrologic system in northeast Mississippi, a two-dimensional cross-sectional digital model was developed from an existing two-dimensional digital model. To make the solutions obtained from the model applicable to any aquifer thickness or other hydrologic condition, a technique for nondimensional simulation was developed. With these techniques, nondimensional water-surface profiles were generated for given stages of trench penetration of the aquifer and for different ratios of anisotropy.