A suspended sediment yield predictive equation for river basins in the South Western river basin system of Ghana

Abstract

An empirical equation that can be used for estimating the suspended sediment yields of river drainage basins without sediment data has been established for basins in the sub-tropical forest Southwestern river basin system of Ghana. The power law equation relates mean annual specific suspended sediment yield (t km-2 yr-1) of the drain-age basin to the basin area (km2) and the mean daily stream discharge (m3/s) of the river at the outlet of the draiinage basin. Values of the parameters of the equation were computed from the least squares linear regression fit to the logarithmic transforms of observed mean annual specific suspended sediment yield, mean daily stream discharge and basin area data at selected river gauging stations in the basin system. The equation was found to fit the observed data very well with a high coefficient of multiple determination, R2 of 0.95. The fit was found to be better than those relating mean annual specific suspended sediment yield to basin area or runoff only. Since many stream gauging stations in the country have no records on fluvial sediment, the empirical equation can be used to obtain preliminary estimates of expected sediment load of streams for engineering design of hydraulic structures such as reservoirs.


Journal of Applied Science and Technology (JAST)
, Vol. 5, Nos. 1 & 2, 2000, pp. 108 - 113