Title: Sediment sources in the upper reaches of a valley and ridge watershed Authors
Submitted to: Journal of Soil and Water Conservation
Publication Type: Abstract Only
Publication Acceptance Date: February 11, 2011
Publication Date: N/A
Interpretive Summary: An interpretive summary is not required.
Technical Abstract: Management practices that effectively target sources of erosion will be essential to reducing inorganic sediment contributions to the Chesapeake Bay. The objective of this study was to identify sediment sources in the headwaters of a small (7.3 km) Valley and Ridge mixed land use watershed. The watershed was divided into five current land use categories. Soil samples were collected in 10-cm increments to the Ap- or A-horizon boundary at 96 locations, stratified by land use. Stream bank/road cut samples were collected from 17 locations. Five samples each were collected at the watershed outlet from the weir pond sediment and from the stream (base and storm flows). Activity of Cs-137 of soil and sediment samples was determined on the less than 2-mm fraction. Landscape source for sediment at the weir pond and in-stream samples was determined using a mixing model and Monte Carlo simulations. During base flow and the early part of two storms, 58 to 60 percent of the sediment could be attributed to upland agriculture and pasture. During the receding part of these storms, contribution from these land uses decreased to 53 percent. Stream bank/road cuts contributed 35 and 44 percent of the sediment in the stream during the rising and falling limbs of the storm flow hydrograph, respectively. Only 4 percent of stream sediment was attributed to the forest, despite forest representing one-third of the watershed area. Upland agricultural land uses represent the predominant sediment sources in this watershed, and therefore should be targeted with mitigating land management practices.