Whether in utility work, road construction or agriculture, grass erosion dams are either net tubes used to slow the flow of runoff or unploughed strips of earth used to prevent soil from being washed away due to erosion. In either application, the goal is the same: reduce the risk of water eroding the surrounding area.
While the application and forms can vary, erosion dams are an essential part of any construction project. This is especially true with very damp areas or construction taking place on a slope. With road construction, the risk of the roadway being undercut by water run off is very real. The danger results from a loss of structural stability which occurs when too much of the supporting soil becomes stripped from beneath the asphalt, eventually causing the shoulder of the road to fail and collapse. Any disturbed earth presents a similar problem, whether from recent utility work or other construction work. To prevent this, mats or tubes of clay and grass stalks are secured to the ground in high risk areas. These products dam up a drainage area or create a catch point for run off, giving it a chance to soak in the soil while also impeding its momentum as it moves downhill.