Surface-Subsurface Model for Trench Infiltration Basins

Abstract

This study presents a surface-to-subsurface two-dimensional (2D) model for the design of infiltration trench basins. It assists engineers in estimating the size of an infiltration basin and in determining the subsurface geometry required for having an adequate hydraulic conductivity. The Federal Aviation Administration (FAA) method is revised to predict the detention storage volume by maximizing the volume difference between the design storm runoff and the basin infiltration rate. Diffusion of the wetting front beneath the basin is depicted by the streamline-equipotential flow-net model derived in this study with consideration of nonisotropic permeability. The required subsurface geometry is found to be related to the width of the basin, and the length of the saturation zone is proportional to the ratio of infiltration rate-to-coefficient of permeability.