Modelling Freshwater Availability Using SWAT Model at a Catchment-Scale in Ivory Coast

Abstract

Sustainable management of Ivory Coast’s freshwater reserve at a catchment scale is an essential way in the policies of land use sustainable management. Thus, the implementation of physical conceptual semi-distributed SWAT model required a good knowledge of the watershed and a large number of physic-chemical data available that have been prior adapted to Ivory Coast’s climatic and soil conditions. The whole simulation span was divided into calibration set (1982-1986) and validation set (1987-1990). The SUFI-2 algorithm was used for parameters optimization. The sensitivity analysis focused on 8 parameters related to runoff, soil, evaporation, main channel and groundwater. The performance criteria were based on the P-factor, R-factor and the two objective functions which are Nash-Sutcliffe coefficient and the coefficient of determination. Although Taabo river basin like African basins suffers from a significant lack of data, the objective functions showed the robustness of the model to climate variability. The calibration launched during a wet period gave objective functions higher than 0.7 while validation performed in less humid period gave performance criteria around 0.6. During the simulation period, Taabo river basin daily green water ranged from 0.044 to 50.257 mm/day with a total average of 3,090.9 mm per year. As for blue water, it is ranged from 0.032 to 0.552 mm/day with an annual total average of 29.19 mm.