Groundwater return flow to streams is important for maintaining aquatic habitat and providing water to downstream users, particularly in irrigated watersheds experiencing water scarcity. However, in many agricultural regions, increased irrigation efficiency has reduced return flows and their subsequent in-stream benefits. Agricultural managed aquifer recharge (Ag-MAR)—where artificial recharge is conducted via irrigation canals and agricultural fields—may be a tool to recover these return flows, but implementation is challenged by water supply and water management. Using climate-driven streamflow simulations, an integrated operations-hydrology model, and a regional groundwater model, we investigated the potential for Ag-MAR to recover return flows in the Henrys Fork Snake River, Idaho (USA). We simulated potential Ag-MAR operations for water years 2023–2052, accounting for both future water supply conditions and local water management rules. We determined that Ag-MAR operations reduced springtime peak flow at the watershed outlet by 10%–14% after accounting for return flows. Recharge contribution to streamflow peaked in July and November, increasing July–August streamflow by 6%–14% and November–March streamflow by 9%–14%. Furthermore, sites where Ag-MAR was conducted incidental to flood irrigation had more water available for recharge, compared to sites requiring recharge rights, which are junior in priority to agricultural rights. Mean annual recharge volume for the incidental recharge sites averaged 12% of annual natural streamflow, ranged from 269 to 335 Mm³, and was largely available in April and October. We demonstrate Ag-MAR can effectively recover groundwater return flows when applied as flood irrigation on agricultural land with senior-priority water rights.

中文翻译：

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在气候变暖的情况下，农业管理含水层补给（Ag-MAR）能否在事先拨款的情况下恢复回流？


地下水回流至溪流对于维持水生栖息地和向下游用户供水非常重要，特别是在缺水的灌溉流域。然而，在许多农业地区，灌溉效率的提高减少了回流及其随后的流内效益。农业管理含水层补给（Ag-MAR）——通过灌溉渠和农田进行人工补给——可能是恢复这些回流的工具，但实施面临供水和水管理的挑战。利用气候驱动的水流模拟、综合运行水文模型和区域地下水模型，我们研究了 Ag-MAR 恢复美国爱达荷州亨利福克蛇河回流的潜力。我们模拟了 2023-2052 年水年的潜在 Ag-MAR 操作，考虑了未来的供水条件和当地的水管理规则。我们确定，在考虑回流后，Ag-MAR 作业使流域出口的春季峰值流量减少了 10%–14%。对径流的补给贡献在 7 月和 11 月达到峰值，7 月至 8 月径流增加了 6%–14%，11 月至 3 月径流增加了 9%–14%。此外，与需要补给权的地点相比，在漫灌中附带进行 Ag-MAR 的地点有更多的水可用于补给，而补给权的优先权次于农业权利。附带补给点的年平均补给量为年自然径流的12%，范围为269 至335 Mm ³ ，主要在4 月和10 月提供。 我们证明，当Ag-MAR应用于具有优先优先水权的农田上进行漫灌时，可以有效地恢复地下水回流。