The use of simple process-based models in the estimate of water balances for mixed land use catchments in East Africa

Abstract

Soil moisture measurements by the neutron probe method were analysed to provide the parameters required for a daily model of actual evaporation from three land uses—grassland, indigenous bamboo and plantation softwood—in the Aberdare range of hills, Kenya. These daily estimates of evaporation were summed to provide annual totals and used, on a percentage land cover basis, in water balance calculations for three experimental mixed land use catchments, two of which were undergoing land use change. The annual water use, given by the difference between rainfall inputs and streamflow outputs, of the undisturbed catchment could normally be predicted to within 10%, whereas differences in the predicted and measured water use of the other two catchments were related to the changes in vegetation.