Increasing meteorological drought frequency and rising water demand drive groundwater exploitation beyond sustainable limits. In heavily-stressed aquifers mitigation strategies, such as Managed Aquifer Recharge (MAR), are needed to restore depleted groundwater storage. MAR is also designed to overcome short dry periods. However, wider impacts of MAR as a drought mitigation strategy remain to be quantified. The objective of this study is to assess impacts of MAR in heavily-stressed aquifers using a case study of the Central Valley in California (USA). The novelty of this study lies in its analytical approach based on long-term observational data of precipitation, groundwater levels, and MAR operations. The impact of MAR operations is assessed regionally and for different temporal scales. Results show spatially-coherent clusters of groundwater level time series in the Central Valley representing three main patterns that manifest themselves in different groundwater drought characteristics and long-term trends. The first regional pattern shows lengthened groundwater droughts and declining groundwater levels over time, indicating effects of over abstraction in aquifer sections without MAR. The second regional pattern shows reduced groundwater drought duration and magnitude related to periodically rising groundwater levels, showing short-term MAR impacts. The third regional pattern shows alleviated groundwater droughts and groundwater levels show a long-term rise, representing long-term MAR impacts. Mitigated groundwater droughts and long-term rise in groundwater levels reveal the value of long-term MAR operations and their contribution toward sustainable groundwater management. Increased institutional support is recommended to ensure longevity of MAR and thereby amplify its success as regional drought mitigation strategy in heavily-stressed aquifers.

不断增加的气象干旱频率和不断增长的需水量使地下水开发超出了可持续的范围。在压力很大的含水层中，需要采取缓解策略，例如管理含水层补给（MAR），以恢复枯竭的地下水存储。MAR还旨在克服短时的干燥期。然而，MAR作为减轻干旱战略的更广泛影响仍有待量化。这项研究的目的是使用美国加利福尼亚州中央谷地的案例研究评估MAR对高应力含水层的影响。这项研究的新颖之处在于其基于降水，地下水位和MAR运行的长期观测数据的分析方法。MAR行动的影响在区域和不同时间尺度上进行评估。结果表明，中央谷地地下水位时间序列在空间上是连贯的，代表了三种主要模式，这些模式在不同的地下水干旱特征和长期趋势中表现出来。第一个区域格局显示，随着时间的推移，地下水干旱持续加剧，地下水位下降，这表明没有MAR的含水层剖面过度开采的影响。第二个区域格局显示地下水干旱持续时间的减少和幅度与地下水位的周期性上升有关，这表明了短期MAR的影响。第三种区域格局显示缓解的地下水干旱和地下水位呈长期上升趋势，这代表了MAR的长期影响。减轻的地下水干旱和地下水位的长期升高揭示了MAR长期运行的价值及其对可持续地下水管理的贡献。建议增加机构支持，以确保MAR的寿命，从而扩大其作为重负荷含水层中区域干旱缓解策略的成功。