MANAGEMENT PRACTICES FOR SEDIMENT REDUCTION FROM FOREST ROADS IN THE COASTAL PLAINS

Abstract

Sediment has been identified as one of the most important nonpoint source pollutants of surface waters. Inforested areas, the predominant source of sediment is from the construction and maintenance of access roads, which contributeas much as 90% of the total eroded sediments. Seven different road management practices were studied to determine theireffectiveness in reducing sediment production from forest roads on nearly flat lands in the lower coastal plains of NorthCarolina. One practice utilized a continuous berm along the roadside, while the other six practices had a noncontinuousberm with different combinations of road surface gravel and roadside vegetative strips. Runoff samples collected duringeleven different rainfall events of varying intensity and duration were analyzed for sediment content. The rainfall amount,intensity, infiltration, and antecedent rainfall conditions were combined into a single energy rating to assist in the overallanalysis. The results of the study showed that a continuous berm maintained along the edge of a forest road can reduce totalsediment loss by an average of 99% compared to the same type road without the presence of a continuous berm. When acontinuous berm is not present, graveling the road surface can reduce the total loss of sediment from roads by an averageof 61% compared to a nongraveled road surface. A 90 cm wide grass strip on the edge of the driving surface can reduce totalsediment loss by an average of 56% compared to a road without a grass strip.