South-Central Section - 57th Annual Meeting - 2023

Paper No. 2-3
Presentation Time: 8:40 AM

UNSTRESSED GROUNDWATER FLOW IN THE BRAZOS RIVER ALLUVIUM AQUIFER WITH IMPLICATIONS FOR TEMPORAL RANGES IN GROUNDWATER TO SURFACE WATER INTERACTIONS


MCVEA, Jairon, Department of Geosciences, Baylor University, One Bear Place #97354, Waco, TX 76798-7354 and YELDERMAN, Joe, Department of Geosciences, Baylor University, One Bear Place #97354, Waco, TX 76706

Groundwater flow paths and flow rates through alluvium aquifers are often oversimplified. This oversimplification may be due to sediment description limitations or aquifer properties obtained using well hydraulics that assume homogeneity. Groundwater travel times to the Brazos River channel can be longer than anticipated when the aquifer gradient is low and flow paths encounter heterogeneity within the lithologic framework. Conversely, travel times to the river channel can be less than anticipated when gradients are steep and homogeneous coarse sediment dominate the lithology within the aquifer while connecting directly to the river. This thesis investigates unstressed groundwater flow rates and flow paths under natural conditions using detailed lithologic logs to recreate more realistic heterogeneity of the Brazos River Alluvium Aquifer characteristics and a 2D finite element steady state model. These estimations provide important insight for surface to groundwater interactions within alluvial aquifers.