CAPACITY ESTIMATION OF SMALL RESERVOIRS USING REMOTELY SENSED DATA: CASE STUDY OF A SEMI ARID REGION OF GHANA

This study develops a correlation between surface area of small reservoirs and their storage volumes using radar images (Envisat ASAR). For each reservoir, a bathymetric survey was carried out and the outline determined. The area and volume for each reservoir were calculated using geographic information system. Radar Imagery was acquired processed and reservoir surface areas extracted. Surface areas obtained from the satellite and the field survey were compared and a regression analysis at 95% confidence interval indicated that the variances of the two surface areas were not significantly different (p<0.05) indicating an existence of relationship between the two surface areas. A regression relationship obtained for the capacity estimation showed a power relationship between surface areas and storage capacities of reservoirs as, Capacity = 0.00876Area(1.44). This relationship can be used as a tool in integrated water resources planning and management to facilitate the process of decision-making by governments and water managers in their quest for improving water availability for irrigated agriculture and other purposes in semi arid regions