GroMoPo Metadata for Little Akaki Watershed SWAT-MODFLOW model

In Ethiopia, groundwater is the main source of freshwater to support human consumption and socio-economic development. Little Akaki watershed is located in Upper Awash basin, known for its high annual rainfall and considered as the potential groundwater recharge zone. On the contrary, urbanization and industrial expansion are increasing at an alarming rate in the area. This became a concern threatening the groundwater resources' sustainability. To address these challenges, integrated analysis of groundwater recharge and groundwater numerical simulations were made. For groundwater recharge estimation, SWAT model was used. The result indicated that recharge in the watershed mostly occurs from July to October with maximum values in August. On average, the estimated annual catchment recharge was 179 mm. For the numerical simulation and prediction of the groundwater flow system, MODFLOW 2005 was used. The model simulations indicated that the groundwater head converges towards the main river and, finally, to the outlet of the watershed. The study indicated areas of interactions between the river and groundwater. The scenario examination result reveals increasing the present pumping rate by over fifty percent (by 50%, 100%, and 200%) will surely cause visible groundwater head decline near the outlet of the watershed, and substantial river baseflow reduction. The recharge reduction scenario also indicates the huge risk of groundwater sustainability in the area.埃塞俄比亚境内，地下水是支撑人类生活消费与社会经济发展的核心淡水来源。小阿卡卡流域（Little Akaki watershed）坐落于阿瓦什河上游盆地，该区域年降水量充沛，被视作潜在地下水补给区。与之形成鲜明反差的是，该区域的城市化与工业扩张正以惊人速度推进，这已成为威胁地下水资源可持续性的重大隐患。为应对上述挑战，研究团队开展了地下水补给综合分析与地下水数值模拟工作。在地下水补给量估算环节，采用了SWAT模型（SWAT model）。结果显示，该流域的地下水补给主要集中于7月至10月，补给峰值出现在8月。经估算，流域年均地下水补给量为179毫米。针对地下水流系统的数值模拟与预测，研究采用了MODFLOW 2005模型（MODFLOW 2005）。模拟结果表明，地下水位逐渐向主河道汇聚，最终流向流域出口。研究还识别出了地表水与地下水的交互区域。情景模拟结果显示，将当前抽水速率分别提升50%、100%及200%时，流域出口附近的地下水位将出现显著下降，同时河道基流量也会大幅减少。补给量缩减情景同样表明，该区域地下水资源的可持续性面临极大风险。