Blue-green water resource availability dynamics in the upper Awash basin, central Ethiopia: implications for agricultural water scarcity assessment

Abstract

Quantifying and characterizing the spatial distribution of freshwater availability and water scarcity plays an indispensable role in managing water resources in a basin. This study aimed at quantifying green and blue water resource availability using an eco-hydrological model under different land use land cover conditions between 2000–2010 and 2020 in the upper Awash basin, central Ethiopia. Further, the agricultural water scarcity is assessed for dominantly cultivated crops in the basin. The freshwater components such as the green water (GW) flow (∼1041–1240 mm/yr), blue water (BW) flow (277–304 mm/yr), and GW storage (809-872 mm/yr) were observed to be high in the western highlands compared to the central and eastern parts of the basin. The results of GW scarcity indices show low to moderate scarcity for rainfed crops, and moderate to significant BW scarcity for irrigated sugarcane. Integrating GW potential to reduce BW scarcity in the basin is thus crucial.