Impacts of Climate Change on Water Resources in Lake Guiers, Senegal

Abstract

Lake Guiers is a shallow reservoir located in the north-western part of Senegal. Its water is used both for irrigating crops and as a drinking water resource for urban centres, including Dakar, the capital of Senegal, as well as for the local population and animal herds. During the last three decades, increasing population, changing patterns of water demand has pressurized Lake Guiers's freshwater resources. To address the challenges that climate change and population growth poses in Lake Guiers water resources, it is necessary to consider its potential impacts on di erent dimensions of water resources. Therefore, this research aim to assess recent and future patterns on climate and future water situation (water availability and demand) in Lake until 2030. To achieve the objectives of this research, Lake Guiers climatic simulations based on the representative concentration pathways (RCPs) 4.5 and 8.5 has been analyzed and future water availability and demand has been modeled under scenarios of climate change and population growth by applying the Water Evaluation And Planning System model (WEAP). The results show that the basin of Lake Guiers experiences an increase of temperature of about 1, 2 C and an elevated warning, leading to signi cant increase of atmospheric water demand is projected. In addition an increasing trend in precipitation (+6.1mm/year) has been observed from 1988-2011 and precipitation projections reveal changes an increase trend ranging between 5 and 48% in Lake Guiers area in the near-future (2050s). However, at the end of the century (2100s) an decrease of precipitation for RCP 4.5 and RCP 8.5.scenarios is projected. The changes in evapotranspiration mostly follow those from the mean precipitation and temperature with more evapotranspiration during the near future and decrease in the late century. In terms of water availability and demand, water stored in the reservoir (Lake Guiers) will be su cient when all projects are implemented however, the pressure on Lake's water resources will increase, leading to greater competition between agriculture and municipal demand sites. Decreasing in ows scenario via taouey canal due to climate change will aggravate this situation.