Soil Management for Stormwater Services.

Construction of roads and buildings necessarily involves a high level of disturbance in order to provide suitable conditions for such structures.   Topsoil is removed and the building site is graded, usually through a process of “cut and fill,” during which subsoils or saprolite may be the material at the surface when grading is complete.  Often these areas are planted to grass or landscape plants, which may have  great difficulty in becoming established and require frequent watering due to poor rooting.  In addition, even with vegetation, it is likely that infiltration will be relatively low, resulting in excessive runoff relative to undisturbed conditions.  We have been testing a number of management practices designed to alleviate the plant establishment problem and at the same time greatly improve infiltration.  Research plots in simulated construction conditions have demonstrated that tillage and vigorous vegetation establishment can increase infiltration and maintain it for at least several years.  Amendment with compost may have additional benefits, but this was not as clear.  More recently, we are testing the concept of tillage and compost amendment on existing roadside areas to reduce runoff from roads.  Preliminary results suggest that tillage with compost amendment may improve runoff infiltration compared to the existing conditions.