Assessing water balance dynamics: a comprehensive gis-based study

Abstract

This study investigates the spatial variability of surface water balance within the Semen Omo Zone in Ethiopia, leveraging data from the Global Land Data Assimilation System (GLDAS) and Empirical Bayesian Kriging (EBK) techniques. The primary parameters analyzed include total precipitation rate (TPR), evapotranspiration (ET), storm surface runoff (SRO), and baseflow groundwater runoff (BF). The study focuses on two scenarios: Scenario I, which considers only surface water components (TPR-ET-SRO), and Scenario II, which incorporates partial groundwater (TPR-ET-SRO-BF). In Scenario I, significant variations in water balance were identified across different watersheds. Watersheds such as WS16, WS15, and WS14 exhibited surplus water, while WS3 showed a notable deficit, indicating insufficient precipitation compared to evapotranspiration and runoff. Scenario II provided a more comprehensive analysis, revealing that watersheds WS17, WS14, and WS6 experienced substantial water deficits when both surface and groundwater components were considered. Conversely, watersheds like WS21 and WS19 were identified as water-efficient areas. The geological context significantly influenced the water balance outcomes. Regions underlain by old crystalline granite schist diorite and marine sediments demonstrated higher water budgets in Scenario I. Scenario II indicated the crucial role these formations play in groundwater recharge and storage. The findings underscore the necessity of integrated water management practices that consider both surface and groundwater resources alongside geological variability. This comprehensive analysis offers valuable insights for policymakers and water resource managers in developing targeted strategies for sustainable water management, ensuring long-term water resource sustainability in the Semen Omo Zone and potentially other similar regions.