Hydrological response of OTI river to climate and land use land cover (lulc) dynamics, Ghana.

Abstract

Climate and LULC dynamics are the main factors impacting the life of water bodies, especially rivers. As a result, numerous studies are turning to issues revolving climate, LULC, and water supply. This thesis did a 30-year investigation into the hydrological response of Oti River to climate and LULC dynamics, Ghana. Specifically, the study evaluated the trends of change in the Oti River basin as a result of climate and LULC dynamics between 1990-2020 using the Mann-Kendall test tool and ArcGIS respectively. The SWAT model further examined the combined impact of Climate and LULC dynamics on inflows and outflows. Results from the Mann-Kendall test indicates that, annual temperature has consistently been high over the years. A computed p value of 0.106, signifies that, there are no significant trends in temperature, however, there is a rise in general annual temperatures in the area leading to increased evaporation rates in the river, more inflows and less outflows. The computed p-values (0.388, 0.320) for the two weather stations indicated that there are no significant trends in rainfall but rainfall is generally decreasing in the Oti Catchment. Results from the change detection analysis indicated that, farmlands, water and the closed forest are being lost to open forest, built-up and bare lands. Due to the recent bareness of the lands, runoffs during rainstorms are made easier and there has been significant sedimentation. The Oti River's inflows and outflows are subsequently impacted by this. The SWAT model's calibration and validation confirms this by showing a good correlation between the simulated and actual flows.