Regional-scale interactions between groundwater and surface water under changing aridity: evidence from the River Awash Basin, Ethiopia

Relationships between surface waters and groundwaters at basin scale are rarely investigated but have important implications for water resource development management. Here, we integrate evidence from geochemical tracers piezometry to advance the understanding of regional-scale, groundwater–surface interactions in River Awash Basin Ethiopia. Hydrological characteristics consistent with those observed other semi-arid arid basins where rivers predominantly losing act as a source recharge rather than sink groundwater discharge. Further, regional flow originating highlands exits catchment discharging riverine drainage. Consequently, abstraction several regional-scale aquifers lowlands is not expected impact river flow. However, salinity presents major threat irrigation supply. We identify critical areas managing inflows, use, wetlands quality that significant security across basin.