Title: Modelling the hydrological processes of Koupendri catchment Northwest, Benin

Authors: Chukwuebuka Vincent Azuka; Attanda Muinou Igué; Bernd Diekkrüger

Addresses: Department of Soil Science, University of Nigeria, 410001 Nsukka, Enugu State, Nigeria; West African Science Service Centre on Climate Change and Adapted Land Use (WASCAL), Climate Change and Water Resources GRP, University of Abomey Calavi, 01 BP-566, Cotonou, Benin ' Laboratory of Soil Sciences, Water and Environment, National Institute of Agricultural Research of Benin, 01 B.P. 988 Cotonou, Benin ' Department of Geography, University of Bonn, Meckenheimer Allee 166, D-53115 Bonn, Germany

Abstract: This study calibrated and validated rainfall-runoff model (WaSiM) to aid decisions on sustainable management of scarce water resources in Koupendri catchment. The model was successfully calibrated (NSE = 0.61; R² = 0.61, RMSE = 0.63) and validated (NSE = 0.68; R² = 0.78; RMSE = 0.57) using optimised soil and land use parameters. Though the model underpredicted some of the peak flows, the overall calibration result could be adjudged satisfactory with a p-factor of 0.94 and an r-factor of 0.93 which were all within the acceptable range of uncertainty. Evapotranspiration and discharge constituted 98%-99% of the total water balance of the catchment while the change in soil moisture storage constituted only < 2%. Surface runoff was the predominant streamflow component (86%-90%), suggesting infiltration excess overland flow as the main runoff generation mechanism for the catchment. The water balance reflected the hydro climatic conditions of the catchment with actual evapotranspiration ranging between 68% and 75% of the total annual rainfall.

Keywords: surface runoff; rainfall-runoff; water resources; hydroclimate; hydrological.

DOI: 10.1504/IJHST.2021.116663

International Journal of Hydrology Science and Technology, 2021 Vol.12 No.2, pp.142 - 163

Accepted: 30 Apr 2020
Published online: 29 Jul 2021 *

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