Rainfall-Runoff Modelling for Sustainable Water Resources Management: The Case of Gumara Watershed, Ethiopia

No Thumbnail Available



Journal Title

Journal ISSN

Volume Title


Addis Ababa Universty


Flow estimation at a point in a river is vital for a number of hydrologic applications including flood forecasting, water resource management, and for development applications. This paper presents the result of a watershed scale rainfall-runoff modeling on gaged part of Gumara watershed using the hydrologic model HEC-HMS in a GIS environment. The model in combination with GIS extension HEC-GeoHMS, was used to convert the precipitation excess to overland flow and channel runoff. Rainfall data used gaged precipitation alone from nine meteorological stations. The simulation was done for a period of 5 years. The predicted hydrograph was calibrated against observed one and the model parameters were optimized for good simulation. The predicted peak discharge, using rain gage data, was close to the observed value and the smaller discharges followed the observed trend. But the simulated peak value was very far apart .The simulated peak discharge has a value of 578.9 m3/s while the observed discharge is 256.9 m3/s, which has a difference of 322 m3/s. The model framework developed in the study considered the spatial variation in the runoff response of the watershed through the use of curve numbers based on soil type and land use, and the spatial distribution of the rainfall in the watershed by using rainfall data from a number of rain gage stations located in different parts of the basin.



Gumara Watershed