USING A SIMPLE FINITE ELEMENT MODEL TO EXPLORE GROUNDWATER FLOW DYNAMICS IN A FLUVIAL AQUIFER

Fluvial aquifers are notoriously heterogeneous. Groundwater models often account for horizontal heterogeneity in aquifer parameter data obtained from wells using techniques such as pumping or slug tests that assumed vertical homogeneity. This study compared Darcian flow calculations using aquifer parameters collected from wells assuming vertical homogeneity to similar calculations using detailed stratigraphic data obtained from cores. Groundwater flow through the detailed lithology was evaluated using a 2-dimensional finite element model that tracked flow paths, flow rates, and particles to gain insights into the flow dynamics in the Brazos River Alluvium Aquifer (BRAA) near the City of Waco in McLennan County, Texas. Results indicated a highly variable flow system with significant implications for managing groundwater/surface-water interactions in the BRAA and fluvial aquifers in general.