A shared water risk assessment for a vulnerable river basin: River Rwizi in Uganda

Abstract

Covering approximately 8,000 km 2 , the River Rwizi catchment stretches across 10 districts in south-western Uganda. Common economic activities carried out include agriculture, fish farming, tourism and local industry. Water users include industries and a municipality. In recent years, the catchment has featured prominently in national news due to frequent water resource problems, especially during the dry season. A water risk and sustainability study was carried out to support water stewardship initiatives and the development of a catchment management plan. The study examined the hydrology and water use patterns in the catchment. Uneven rainfall distribution (both in time and space), topography and wetlands drive the catchment's hydrology. However, existing river flow data cannot be relied upon, due to existing hydraulic characteristics at gauging locations as well as inconsistency in the record lengths. Groundwater quantity and quality are highly variable, and generally poor due to the geology of the area. Meanwhile, projections for domestic, agricultural and industrial water demand to 2035 indicate a steady increase, largely as a result of population growth and urbanisation. Pollution loads are also projected to increase. The study identified and ranked the key water-related risks to users in the catchment, including the causal factors. Possible mitigation measures were examined and a programme of long and short-term actions identified.