Optimizing the Design of Infiltration Trenches for Stormwater Recharge in Harris County, Texas

Abstract

Houston, Texas and Harris County, Texas are unfortunately susceptible to both flooding and drought. To alleviate problems from both of these extreme events, infiltration managed aquifer recharge (MAR) systems can be implemented. In this study, the spacing, width, and depth of rectangular parallel infiltration trenches are compared for three soil types and three water table (WT) depths to determine the resulting infiltration rates. Analysis was conducted using two-dimensional numerical simulations with the HYDRUS software package. Modeling of two groups was conducted; one varied the number of trenches in a fixed area and the other varied the width and depth of trenches while maintaining a constant trench volume. Increasing the number of trenches within a fixed area resulted in (1) increased infiltration that slightly diminished as more trenches were added and (2) an increased proportion of infiltration coming from the bottom of the trenches compared to the sides. Increasing trench width while decreasing trench depth resulted in (1) decreased infiltration and (2) an increased proportion of infiltration coming from the bottom of the trenches compared to the sides. Varying the depth to water table did not have a significant impact on the infiltration rate for most simulations in this study. However, the impact of the water table is expected be evident for smaller depths to water table. Functions were created for both modeling groups that show similar trends of infiltration rates for the three tested soil types.