Aug 25, 2014

Erosion Eliminated in Tennessee County

Civil engineers constantly are in search of solutions for scour protection that do not include hard armament applications. The method deployed at the Williamson County Landfill, located in Franklin, Tenn., is an example of these practices.

Williamson County’s landfill had a drainage area that was in need of a ditch and ditch treatment. During normal rain events (five-year and less storms), the area would drain to a low area and then sheet flow into an existing drainage culvert. When the storm events were above normal (five-year and greater storms), the storm water would begin to erode the area and form an unnatural ditch, transporting sediment-laden storm water into a nearby stream. The area would have to be regraded and fixed every time because it was used to access the existing landfill monitoring wells.

Typar Grassprotecta mesh was selected for scour protection and installed on an area designed for the high flow. Due to the soil found in this area, a double net straw blanket also was selected to be installed underneath the Grassprotecta to help contain the smaller soil particles. The owner prepared the area by installing a ditch designed by Civil & Environmental Consultants Inc. that would convey the water to the existing culvert. The owner added seed and fertilizer and pinned the Grassprotecta and straw blanket directly to the
new ditch.

Typar Grassprotecta mesh allowed the county to eliminate the erosion problem in this area and also provided a green solution. The mesh served as a soil erosion product and also allowed the landfill personnel to be able to access the existing monitoring wells by vehicle.

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