Runoff and Erosion Reduction Via Drainage and Increased Infiltration

摘要

The study investigated the effect of soil air entrapment on filtration runoff and erosion and the possibilities of reducing the negative effects. Four laboratory studies are reported. An infiltration model for infiltration under trapped air conditions based on a modified Green and Ampt (1911) equation was developed. Infiltration of high intensity rainfall into soils, containing shallow water tables or relatively impermeable layers, is reduced and in some cases virtually stopped if the soil air cannot move laterally to a venting location. The release of entrapped soil air through subsurface drainage systems placed at the depth of the restrictive layer or through surface soil pores can increase the infiltration rate. This enhanced infiltration reduces the quantity of surface runoff resulting in less erosion and providing a method of nonstructural flood control on some small watersheds.