ABSTRACT

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

摘要

流域规模的地表水与地下水之间的关系鲜有研究，但对水资源开发和管理具有重要意义。在这里，我们整合了来自地球化学示踪剂和测压法的证据，以增进对埃塞俄比亚阿瓦希河流域的区域规模，地下水与地表水相互作用的理解。水文特征与在其他半干旱和干旱盆地观察到的水文特征一致，在这些河流中，河流主要流失，并作为补给源而不是地下水汇。此外，源自高地的区域地下水流从集水区流出，而不是排入河流排水。因此，预计从低地的几个区域规模含水层抽取地下水不会影响河流流量。然而，盐度对灌溉和供水构成了重大威胁。我们确定了管理流入，用水，湿地和水质的关键区域，这些区域对整个流域的水安全具有重大影响。