Past Flood Characteristics of Mpologoma River Basin, in Eastern Uganda

Floods are most recurring natural hazards in Eastern Uganda with a devastating effect on socio-economy and ecosystem. Characterization of the past flood events is an important aspect in flood risk mitigation planning. The study determined past flood frequency and magnitude. HEC-RAS was used for flood inundation mapping using discharge data for Mpologoma outlet from MWE. The HEC-HMS performance during calibration was (R2 = 0.75, NSE = 0.75, PBIAS = 20.55) and validation R 2 = 0.79, NSE = 0.77, PBIAS = 0.52) found to be satisfactory. Flood frequency was analyzed with AMS based on discharge corresponding to 2, 5, 10, 25, 50 and 100 year return periods in HEC-SSP. Results showed highest flood events in Mpologoma oulet with a frequency of 63 with a 2 year return period in 1998 and a frequency of 15 flood events in 2008 with a 5 year return, in 1998, a frequency of 41 events 2 year return periods and highest was 10 with 5 year return periods in 2008 from (1980- 2009). Inundation area increases with the frequency of floods. Mpologoma River basin is prone to floods