Characterizing Spatiotemporal Patterns of Land Subsidence after the South-to-North Water Diversion Project Based on Sentinel-1 InSAR Observations in the Eastern Beijing Plain
Characterizing Spatiotemporal Patterns of Land Subsidence after the South-to-North Water Diversion Project Based on Sentinel-1 InSAR Observations in the Eastern Beijing Plain
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DOI：
10.3390/rs14225810
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发表时间：
2022-11
期刊：
影响因子：
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通讯作者：
Yuanyuan Liu;Xia Yan;Yuanping Xia;Bo Liu;Zhong Lu;Meiming Yu
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文献类型：
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作者：
Yuanyuan Liu;Xia Yan;Yuanping Xia;Bo Liu;Zhong Lu;Meiming Yu
北京东部平原近几十年来一直处于严重的地面沉降状态，这主要与地下水资源的长期过量开采有关。自2014年底以来，南水北调工程使北京平原地区年供水量达到数亿立方米，减少了地下水开采量，改变了地面沉降现状。利用2015年7月至2021年12月的Sentinel-1 SAR数据，采用渐进小基线子集（SBAS）干涉合成孔径雷达时间序列分析方法，获得了北京平原东部地面沉降的时空变化特征。然后，我们分析了InSAR提取的沉降和地下水位变化的相关性，应用交叉小波方法。结果表明，成功探测到两个主要沉降带，最大变形速率为-150 mm/年，最大累积变形为-950 mm; 2016 - 2021年不同阶段地面变形显示，即使在沉降严重的地区，主要变形的面积和幅度也明显减缓，特别是在2017年，这比北京SNWD项目的启动时间晚了大约两年。进一步研究发现，InSAR反演的地面沉降滞后于地下水位的变化，滞后时间约为1-2个月，说明地下水位波动的动态变化可能是影响严重沉降区地面不均匀沉降的主要因素。最后，从观测到的形变图中，识别出南口-孙河断裂、南苑-通县断裂等地质断裂两侧的差异沉降速率，解释了断层对地下水流的阻断作用。这些研究成果对揭示北京市地面沉降变形机制、建立水文地质模型、辅助决策、预警和减灾具有重要意义。
The eastern Beijing plain has been suffering severe subsidence for the last decades, mainly associated with the long-term excessive extraction of groundwater resource. Since the end of 2014, the annual water supply in Beijing plain has reached several hundred million cubic meters because of the South-to-North Water Diversion (SNWD) Project, which has reduced the groundwater exploitation and changed the status of land subsidence. In this work, we first obtain the current spatiotemporal variations of land subsidence in the eastern Beijing plain by using progressive small baseline subsets (SBAS) InSAR time series analysis method with Sentinel-1 SAR data acquired from July 2015 to December 2021. Then, we analyze the correlations between InSAR-derived subsidence and groundwater level change by applying the cross wavelet method. The results show that two major subsidence zones are successfully detected with the maximum deformation rate of −150 mm/yr and maximum cumulative deformation of −950 mm. Besides, the ground deformation at different stages from 2016 to 2021 reveal that the area and magnitude of major deformation significantly slow down, even in the regions with severe subsidence, especially in the year of 2017, which is about two years later than the start time of SNWD Project in Beijing. Further, we find the InSAR-derived subsidence lags groundwater level change with about 1–2-month lagging time, indicating that the dynamic variation of groundwater level fluctuation may be the main factor affecting the uneven subsidence in the severe subsiding zones. Last, differential subsidence rates are identified at both sides of geological faults, such as Nankou-Sunhe fault and Nanyuan-Tongxian fault, from the observed deformation map, which could be explained that the groundwater flow is blocked when a fault is encountered. These findings can provide significant information to reveal the deformation mechanisms of land subsidence, establish the hydrogeological models and assist decision-making, early warning and hazard relief in Beijing, China.