Impacts of water use on the hydrological regime watercourses

This study was carried out in the Lake Togo catchment area, a key catchment for the economy of the Maritime Region. The field survey focused on market gardening, sugar cane cultivation, flower growing, rice cultivation and the gravel-washing plant as activities where water use appears to be significant. Following the quantification of water use by these activities, simulation tests of various scenarios were carried out to assess the impacts of these uses on river flows using the HYDROTEL model within the Integrated Watershed Management System (GIBSI). The results presented show that the simulation of each of the activities (market gardening, sugar cane and ornamental plants) indicates a 2 per cent reduction in the flow of the Zio and Haho rivers. However, the simulation of a future scenario involving a rice-growing area shows an 18 per cent reduction in the flow of the River Haho and a change in the quantity of water available for various uses within the catchment. This study highlights the more or less significant influence of certain activities on the hydrological regime of watercourses at the catchment level.