The proposed Kabuyanda dam is designed for storage of streamflow, which will limit the water flow and may also possibly alter water quality in the R. Mishumba downstream of the dam. The estimated monthly runoff for R. Mishumba at the proposed dam location indicates a bi-modal variation with two peak flows in April and October of 0.8m³/s and 0.89m³/s, respectively, and a mean annual flow is 0.51m³/s. Based on available data, the river sometimes dries up in the dry months of July and August, and February and September. Downstream of the Kabuyanda dam, the tributaries Rweibare (Kasharira) joins R. Mishumba downstream of the dam, and Rwemango and Kyabaganda join Mishumba about 5 km downstream of the dam. The Rweibare stream contributes about 18% of the 0.61m³/s Average Annual Flow (AAF) of R. Mishumba at the confluence, and the combined flow of Rweibara and Rwemango Rivers is about 56% of the total flow at the confluence.