The impact of land use on water quality of the Lwiro River, Democratic Republic of Congo, Central Africa

Abstract

The water quality of the Lwiro River, Democratic Republic of Congo (DRC), Central Africa, was investigated on a monthly basis from December 1999–October 2000, at six stations along a hydraulic gradient from source to mouth, to evaluate the impact of land use on temperature, Dissolved Oxygen (DO), Biological Oxygen Demand (BOD₅), alkalinity and suspended solids. Upstream, where forests are conserved, minimal changes of physico-chemical parameters of water were observed. Downstream, DO was reduced, due to the increased organic matter content which increased the decomposition rate. BOD₅ and suspended solids increased downstream. Greater changes were found near agricultural areas and villages. Wetlands appear to mitigate BOD₅ and DO impacts.

Keywords: hydraulic gradient, impact mitigation, land use, physico-chemical parameters,water quality parameters, wetlands

African Journal of Aquatic Science 2006, 31(1): 137–143