Assessing Impact of Land Use and Land Cover Change on Groundwater Recharge: The Case of Dire Dawa Watershed, Ethiopia

Abstract

Evaluating the impacts of land use land cover changes on groundwater recharge at the watershed scale can facilitate the development of sustainable water resource strategies. This study investigates the historic land use/landcover change and its potential impacts on the groundwater recharge of Dire Dawa Watershed, Ethiopian. ERDAS Imagine coupled with GIS software to detect a change in land use/land cover in the watershed. Physically-based, semi distributed hydrological model, SWAT model, was utilized to simulate the groundwater recharge associated to land use/land cover changes from 2000 to 2022. Image classification revealed Land use/landcover maps with six Land use/land cover types of three historical periods 2000, 2010, and 2022.Relative change assessment results depict that area under agricultural land and built-up area is expanded by 49.18%, and 22.6 % respectively at the expenses of other revealed Landuse/land cover class. The shrub land and forest decreased by 105.39, and 28.8 respectively as compared from 2000 to 2022 historic land use/ land cover maps. The SWAT model performed well in simulating monthly river discharge. The result shows that,the observed and simulated value is in good fit by R2 of 0.84 and NSE of 0.75. The recharge estimation using the land uses of the years 2000, 2010, 2022 indicates that recharge decreasedby 20 %, 5.17% and 25% between the years 2000 to 2022, 2010 to 2022, and 2000 to 2022 respectively. On the other hand, surface runoff is amplified by 15 % from 2000 to 2010, 5% from 2010 to 2022, and 10% from 2000 to 2022. The results of this research could help watershed managers, Policy makers,and all stalk holders to create sustainable plans for managing water resources and land use land cover.