Land Use and Streamflow (O.D.C. 11)

Abstract

This paper relates the catchment area research methods used in East Africa to those used elsewhere. Routine hydrological measurements have directed attention to the need for understanding the mechanisms of stream production. The classical method has sought to determine statistical relations between streamflow parameters and rainfall before and after the land use change in a catchment, without measuring the numerous factors responsible for the variability of the data. Such calibration periods may last at least 10 years. Under the conditions of rapid changes in land use in East Africa, reliable preliminary results must be achieved quickly and the urgency calls for very intensive methods that aim at a more complete description of the total hydrological cycle in small catchments. Because of the exceptionally favourable climatic and soil con-ditions in high altitude catchments in East Africa, worthwhile results have been obtainable in as little as three years and the main conclusions are summarized.