Water Demand Assessment under Climate Variability Scenarios Using SWAT and WEAP: A Case Study of Kaduna South Catchment

Abstract

This research was structured to examine the impact of the domestic as well as Agricultural water demand on the current and future surface water available within the Kaduna South Catchment of Nigeria. Also taking into consideration climate variability as a factor that will either increase or decrease the temperature as well as the precipitation in the catchment, with significant effect on the stream flow within the Kaduna river basin. A dual Order modelling approach was adopted in this research, in which the Soil and Water Assessment Tool (SWAT) alongside the Water Evaluation and Planning (WEAP) models were engaged to simulate the streamflow of the catchment which was calibrated and validated by the observe streamflow data of the Kaduna river. An Hypothetic approach was employed in observing and analyzing the climate scenarios after which the output data from SWAT model was used as the Input data into WEAP for simulating scenarios of high population of a growth rate of 2.21% and four different climate variability scenarios as temperature were projected to increase by 0.4oC from the observed historical trend. Nevertheless, the overall unmet demand was observed to be 305Mm3 in which 70% account for domestic demand while 30% is the Agricultural unmet demand. The calls for strategic planning and looking out for other source such as underground water and not totally rely on surface water for future water use.