Infiltration Trenches

Infiltration trenches are excavations backfilled with stone aggregate used to capture runoff and infiltrate it to the ground (GUO, 2001). Subsoil with a minimum permeability of 13 mm/h (0.5 in/h) is required for a good performance (U.S.EPA, 1999). The most important processes that must be simulated for an infiltration trench are infiltration, storage and the water flow along the trench. Figure 3.2 shows a workable SWMM representation of an infiltration trench. It consists of a rectangular, fully pervious subcatchment whose depression storage depth equals the equivalent depth of the pore space available within the trench.