The replacement of flood-irrigation systems by drip-irrigation technology has been widely promoted with the aim of a more sustainable use of freshwater resources in irrigated agriculture. However, evidence for an irrigation efficiency paradox emphasizes the need to improve our understanding of the impacts of irrigation transformations on water resources. Here, we developed a distributed hydrological modeling approach to investigate the spatiotemporal effect of flood and drip irrigation on groundwater recharge. The approach recognizes differences in the water balance resulting from the localized application of water in surface drip-irrigated fields and the more extensive application of water in flood irrigation. The approach was applied to the semi-arid Mediterranean region of Valencia (Spain) and calibrated using a multi-objective framework. Multiple process scales were addressed within the framework by considering the annual evaporative index, monthly groundwater level dynamics, and daily soil moisture dynamics. Daily simulations from 1994 to 2015 suggested that, in our hydroclimatic conditions, (a) annual recharge is strongly related to annual rainfall, which had a four times higher impact on recharge than the type of irrigation practice, (b) flood-irrigated recharge tends to exceed drip-irrigated recharge by 10% at annual time scales, (c) however, recharge response to a particular precipitation event is smaller in flood irrigation than in drip irrigation, and (d) 8–18 rainfall events could generate more than half of the annual recharge in drip and flood irrigation, respectively. Our results highlight the importance of understanding the hydrological dynamics under different irrigation practices for supporting irrigation infrastructure policies.

中文翻译：

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使用多目标校准对从洪水到滴灌的转变对地下水补给影响的水文模拟

以滴灌技术取代洪水灌溉系统已得到广泛推广，目的是在灌溉农业中更可持续地利用淡水资源。然而，灌溉效率悖论的证据强调需要提高我们对灌溉改造对水资源影响的理解。在这里，我们开发了一种分布式水文建模方法来研究洪水和滴灌对地下水补给的时空影响。该方法认识到由于在地表滴灌田中局部使用水和在漫灌中更广泛地使用水而导致的水平衡差异。该方法应用于巴伦西亚（西班牙）的半干旱地中海地区，并使用多目标框架进行校准。通过考虑年度蒸发指数、每月地下水位动态和每日土壤水分动态，在框架内解决了多个过程尺度。1994 年至 2015 年的每日模拟表明，在我们的水文气候条件下，(a) 年补给与年降雨量密切相关，其对补给的影响是灌溉实践类型的四倍，(b) 洪水灌溉补给倾向于在年度时间尺度上超过滴灌补给 10%，(c) 然而，洪水灌溉对特定降水事件的补给响应小于滴灌，(d) 8-18 次降雨事件可能产生一半以上分别为滴灌和漫灌的年度补给量。