Effect of land use changes on sediment transport in Goodwin Creek

The Goodwin Creek Research Watershed (21.3 km(2)) is located in the north central part of Mississippi in the bluff hills just east of the Mississippi River floodplain. Land use on the watershed has been surveyed annually and the percentage of cultivated land has decreased from 26% in 1982 to 12% in 1990. During this 9-year period the concentration of fines (<0.062 mm) in Goodwin Creek have decreased by 62%, concentrations of sand (0.062-2.0 mm) have decreased by 66%, and concentrations of gravel (>2.0 mm) have decreased by 39%. The decrease in the percentage of cultivated land affects the sediment budget of the watershed in two ways. A source of readily eroded sediment is removed, and the energy of the flowing water available to erode and transport sediment is reduced. The reduced flow in the channels from the decrease in cultivated land in the watershed was probably the main cause for the lower transport rates of sand and gravel.