STUDIES OF THE EFFECTS OF CHANGES IN LAND USE ON THE HYDROLOGICAL CYCLE IN EAST AFRICA BY MEANS OF EXPERIMENTAL CATCHMENT AREAS

Open Access
Publisher Website
Google Scholar
Abstract
The urgent need for planning information on the effect of changes in land use on water resources in East Africa has necessitated the use of intensive methods of experimental catchment area research in order to produce data on the water balance of different vegetation covers in a matter of years rather than decades. Quantitative water balance studies require an intensive network of raingauges to estimate the volumetric water input with an accuracy comparable with the measurement of outflow. Observations of the soil moisture status and energy balance, in addition to those of rainfall and streamflow are necessary to provide independent checks for “leaks” from the catchments. The successful application of these methods is illustrated from the results of three catchment area experiments in Kenya and Tanzania. The water use of each vegetational complex is characterized by the ratio of the transpiration, E t, to the evaporative demand from an open water surface, E o. This ratio is shown to vary little from year to year despite considerable variation in E t and E o. An intensive method of analysis of stormflow response, based on the construction of a prediction equation relating stormflow to rainfall quantity and intensity and to antecedent surface soil moistrue condition, is described. Results from the application of the method in one of the catchments are presented in detail.

This publication has 4 references indexed in Scilit: