Groundwater Loss and Aquifer System Compaction in San Joaquin Valley During 2012-2015 Drought
Groundwater Loss and Aquifer System Compaction in San Joaquin Valley During 2012-2015 Drought
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DOI：
10.1029/2018jb016083
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发表时间：
2019-03-01
影响因子：
3.9
通讯作者：
Shirzaei, Manoochehr
中科院分区：
文献类型：
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作者：
Ojha, Chandrakanta;Werth, Susanna;Shirzaei, Manoochehr
加州2012-2015年的千年干旱严重影响了中央谷含水层系统，并造成地下水和含水层储存能力的永久性损失。为了量化圣华金河谷南部的这些影响，我们分析了各种补充测量，包括重力恢复和气候实验（GRACE）卫星的重力变化;全球定位系统，干涉合成孔径雷达和引伸计的垂直陆地运动;和地下水位记录。Sentinel-1卫星获得的干涉测量数据集仅涵盖2015年1月至2017年10月期间，而其他数据集涵盖整个干旱时期。使用GRACE观测，我们发现圣华金河谷的平均地下水流失量为6.12.3km（3）/年，这是2011年10月至2015年9月期间流失的总量为24.29.3km（3）。这与仅使用全球定位系统变形数据估算的29.258.7 km（3）的总体积一致。我们的研究结果突出了使用垂直地面运动数据来评估地下水流失的优势，从而填补了GRACE和GRACE-Follow-On任务之间的空白，并补充了他们的估计。我们进一步确定，0.4-3.25%的含水层系统的存储容量是永久性的损失，在这个干旱时期。对比2015年9月以后的地下水位和垂直地面运动数据，我们确定弱透水层和含水层单元内地下水位的平衡时间为0.5- 1.5年，在此期间，弱透水层的残余压实和地面沉降持续到干旱期之后。我们认为，这种研究可以推进不断变化的地下水资源的知识，使管理者和决策者能够更好地评估干旱期间和之间的水的需求和供应。
California's millennium drought of 2012-2015 severely impacted the Central Valley aquifer system and caused permanent loss of groundwater and aquifer storage capacity. To quantify these impacts within the southern San Joaquin Valley, we analyze various complementary measurements, including gravity changes from Gravity Recovery and Climate Experiment (GRACE) satellites; vertical land motion from Global Positioning System, interferometric synthetic aperture radar, and extensometer; and groundwater level records. The interferometric data set acquired by the Sentinel-1 satellite only spans the period January 2015 and October 2017, while the other data sets span the entire drought period. Using GRACE observations, we find an average groundwater loss of 6.12.3km(3)/year as a lower bound estimate for the San Joaquin Valley, amounting to a total volume of 24.29.3km(3) lost during the period October 2011 to September 2015. This is consistent with the total volume of 29.258.7km(3), estimated using only Global Positioning System deformation data. Our results highlight the advantage of using vertical land motion data to evaluate groundwater loss and thus fill the gaps between GRACE and GRACE-Follow-On missions and complement their estimates. We further determine that 0.4-3.25% of the aquifer system storage capacity is permanently lost during this drought period. Comparing groundwater level and vertical land motion data following September 2015, we determine an equilibration time of 0.5-1.5years for groundwater levels within aquitard and aquifer units, during which residual compaction of aquitard and land subsidence continues beyond the drought period. We suggest that such studies can advance the knowledge of evolving groundwater resources, enabling managers and decision makers to better assess water demand and supply during and in-between drought periods.