Application of swat model in assessing the effect of climate change on water quantity and quality :

Abstract

In this study case, nutrients were considered to be an important water quality concern in the River Malaba due to high eutrophication problem of Malaba river. Nitrogen and phosphorus are the two major nutrients originating from subsistence agriculture and livestock grazing. Increased N and P fertilizer application has enlarged N and P river Malaba through runoff and leaching making river Malaba water quality vulnerable to climate change and land use. Quantitatively, Malaba River is very vulnerable to climate change because it relies heavily on rainfall as its main flow contributor. This study’s main objective was to assess the effect of climate change on water quantity and quality in Malaba River Catchment, Uganda and it was achieved by simulating the climate variables with calibrated SWAT model inputs for a period of 35 years from 1979 to 2013. The trend analysis was done by Regression test and its significance was determined using the T-test approach. SWAT model was successfully calibrated and validated with NSE of 0.93 and 0.90 respectively. Therefore, the Ministry of Water and Environment Uganda and other stake holders will be empowered with these results to carry out water resources management plan to prevent the effects that might rise from the high and low flows and also deterioration of water quality.