An assessment of the capacity of River Rwizi to supply water to the projected Mbarara City

Abstract

River Rwizi catchment has experienced years of environmental degradation; subsequently, the quality and quantity of its water has deteriorated, and the wetlands around the river have dried up and the fringes have been cleared for other land-use/cover. Yet the River is one of the key sources of water in the catchment, and is likely to be the main source of water for Mbarara city. This study therefore intended (i) to determine the major sources of water in Mbarara City and (ii) assess the capacity of River Rwizi to meet the projected Mbarara city water demand. Semi-structured questionnaire, consultations and modeling were used to achieve the above objectives. Semi structured questionnaires were administered to 143 households. Consultations were made with Mbarara city physical planning committee, manager national water and sewerage cooperation and Directorate of Water Resources. Future discharge was predicted using HEC-HMS software and matched with water demand of Mbarara city. Major sources of water in Mbarara City included surface water from river Rwizi and ground water. Water from the river is abstracted by NWSC and distributed as tapped water to different water users (65%), other water users fetch directly from the river (17%), while others use protected springs (6%) and boreholes (12%). The river will not be able to meet the demand of water in all times by 2040, particularly in the months of August and September when the flow is predicted to be too low. The study recommends river Rwizi macro catchment restoration and Development should comply with environmental regulations.