Abstract Groundwater overdraft due to extensive irrigation has led to a shallow aquifer depletion crisis in the Haihe River basin. Quantitative simulation of the variations in shallow groundwater and crop yield under different conditions of limited exploitation using a distributed hydrological model is important in the well-irrigated plain of this basin. Based on multiple modeling experiments by a modified Soil and Water Assessment Tool (SWAT) model, three limited irrigation schemes for winter wheat (Triticum aestivum L.) were selected as simulation scenarios. The simulated results using the SWAT model showed that under scenario 1 (applying two rounds of irrigation corresponding to the jointing and heading stages of winter wheat), the average rate of decline in the shallow groundwater table was approximately 2/3 of that under the basic scenario (current irrigation schedule), but the winter wheat yield decreased by 13% compared with the basic scenario. Under scenario 2 (applying one round of irrigation at the jointing stage of winter wheat), the average rate of decline in the shallow groundwater table was approximately 1/4 of that under the basic scenario, but the reduction in the winter wheat yield compared with the basic scenario increased to 28%. The amount of overexploited shallow groundwater in the cropland area decreased from 17.5 × 108 m3 a−1 (under the basic scenario) to 11.0 × 108 m3 a−1 under scenario 1 and 4.5 × 108 m3 a−1 under scenario 2. Under scenario 3 (rain-fed conditions during the winter wheat season), the regional variation in the shallow groundwater table shifted to a recovery trend with an average rate of 0.22 m a−1, which was equivalent to restoring 3.5 × 108 m3 a−1 of shallow aquifer storage in the cropland area. However, the reduction in the winter wheat yield compared with the basic scenario reached 54% under the rain-fed scheme. Considering the trade-off between groundwater conservation and crop production under limited exploitation, linear programming was used to optimize the irrigation schedule at the subbasin scale. As a result, to satisfy the constraint of stopping groundwater drawdown, the average minimal reduction in the winter wheat yield would be 42% under the optimal irrigation schedule. By contrast, to satisfy the constraint of restricting the reduction in the crop yield to within the threshold required to maintain winter wheat self-sufficiency, the minimal rate of decline in the shallow groundwater table would be 0.26–0.52 m a−1 under the optimal irrigation schedule. In addition, the uncertainty in the simulated shallow groundwater variation in this study was acceptable, indicating that the above assessments could provide reasonable references for regional groundwater management.

中文翻译：

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使用 SWAT 模型评估海河流域灌溉良好平原浅层地下水保护与有限开发作物生产之间的权衡

摘要 大量灌溉导致地下水超采，导致海河流域浅层含水层枯竭危机。在该盆地灌溉良好的平原上，使用分布式水文模型定量模拟不同有限开发条件下浅层地下水和作物产量的变化非常重要。基于改进的土壤和水评估工具 (SWAT) 模型的多个建模实验，选择了三种冬小麦 (Triticum aestivum L.) 的有限灌溉方案作为模拟场景。SWAT模型的模拟结果表明，在情景1（冬小麦拔节期和抽穗期对应的两轮灌溉）下，浅层地下水位的平均下降速度约为基本情景（当前灌溉计划）下的2/3，但冬小麦产量与基本情景相比下降了13%。情景2（冬小麦拔节期施一轮灌溉）下，浅层地下水位平均下降速度约为基本情景下的1/4，但冬小麦产量下降较基本情景增加到28%。耕地浅层地下水超采量从17.5×108 m3 a-1（基本情景下）减少到情景1下的11.0×108 m3 a-1和情景2下的4.5×108 m3 a-1。 情景下3（冬小麦季节的雨养条件），浅层地下水位的区域变化转向恢复趋势，平均速率为0.22 ma-1，相当于恢复了3.5×108 m3 a-1的农田区浅层含水层蓄水量。然而，在雨养计划下，冬小麦产量与基本情景相比减少了 54%。考虑到地下水保护和有限开发作物生产之间的权衡，线性规划被用来优化子流域尺度的灌溉计划。因此，为了满足停止地下水下降的约束条件，在最佳灌溉计划下，冬小麦产量的平均最小减幅为 42%。相比之下，为满足将作物产量下降限制在维持冬小麦自给自足所需的阈值内的约束条件，在最佳灌溉计划下浅层地下水位的最小下降率为0.26-0.52 m a-1。此外，本研究模拟的浅层地下水变化的不确定性是可以接受的，表明上述评估可以为区域地下水管理提供合理的参考。