Sediment Production From Small Undisturbed Forested Basins In The Upper Coastal Plain

Abstract

Forest lands in the Upper Coastal Plain (UCP) of the American South are widely recognized as producing water with relatrvely low amounts of sediment. Previous research has established that sediment concentrations from forest basins lacking well-defined channel networks averages 5.3 to 6.2 kg of sediment per hectare per centimeter of runoff (kg/ha-cm) in this physiographic region. Our results indicate that sediment concentrations are much greater in forested basins which have channel networks. Eight catchments in the Holly Springs National Forest (HSNF) of Mississippi with areas between 1.8 and 2.8 ha were monitored from 1982 to 1989. Mean sediment concentration for all basins during this period is 52.4 kg/ha-cm. This value is comparable to the 77.7 kg/ha-cm observed for another UCP basins with channel development. Sediment concentrations in the HSNF basins do not correlate with either stormflow peak discharge or water yield, nor do basin morphometric attributes appear to explain the observed variation in concentrations. The presence of continuous ground cover and cohesive bank materials, and the lack of observed surface erosion in the HSNF catchments all suggest that the source of this sediment is in-channel storage. Moreover, these results indicate that relatively high sediment concentrations can be produced by stable forested basins which have not been disturbed by timber harvesting.

Citation

Marion, Daniel A.; Malstaff, Greg; Halverson, Howard G. 1996. Sediment Production From Small Undisturbed Forested Basins In The Upper Coastal Plain. In: Wang, S.S.Y.; Langendoesn, E.J.; Shields, F.D., eds. Proceedings of the Conference on Management of Landscapes Disturbed by Channel Incision; Oxford, MS; 1996 July 15: 873-878