{"title":"地下结构对中国上海典型城区地下水位的长期影响","authors":"X. W. Wang, Y. S. Xu","doi":"10.1007/s10040-024-02796-w","DOIUrl":null,"url":null,"abstract":"<p>The effect of subsurface structures in blocking groundwater seepage has a long-term influence on groundwater level (GWL). A finite difference method (FDM) model considering the actual distribution of subsurface structures in an urban area of Shanghai (China) was established to predict GWL in the phreatic aquifer (Aq0) and the first confined aquifer (AqI). The equivalent hydraulic conductivity (<i>K</i><sub>eq</sub>) of model elements containing subsurface structures, calculated by the effective medium theory, was applied to the model. The predicted GWL fitted the monitored value in Aq0 well. Additional subsurface structures were added to the model to analyze the influence of the distribution type and the proportion (%) of the volume of subsurface structures that occupy the aquifer (<i>V</i><sub>u</sub>). Four scenarios with different distribution types (concentrated, subconcentrated, subscattered, and scattered) and ten scenarios with <i>V</i><sub>u</sub> varying from 5 to 50%, were analyzed. In all scenarios, the regional average GWL in AqI increased compared to the actual conditions because of the decrease in <i>K</i><sub>eq</sub> and the blockage effect on groundwater flow. The influence of scattered distribution on the regional GWL distribution was the smallest, and the subscattered distribution resulted in the most nonuniform GWL redistribution. The blockage effect of the subsurface structures gradually increased with increasing <i>V</i><sub>u</sub>. The increasing rate of Δ<i>L</i><sub>av</sub> (difference in regional average GWL between the predicted and actual scenarios) becomes considerable when<i> V</i><sub>u</sub> is ~29%. Hence, the projected increase in volume of subsurface structures in AqI under the assumed subscattered distribution is suggested to be <29%.</p>","PeriodicalId":13013,"journal":{"name":"Hydrogeology Journal","volume":"18 1","pages":""},"PeriodicalIF":2.4000,"publicationDate":"2024-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Long-term effects of subsurface structures on groundwater level in a typical urban area of Shanghai, China\",\"authors\":\"X. W. Wang, Y. S. Xu\",\"doi\":\"10.1007/s10040-024-02796-w\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>The effect of subsurface structures in blocking groundwater seepage has a long-term influence on groundwater level (GWL). A finite difference method (FDM) model considering the actual distribution of subsurface structures in an urban area of Shanghai (China) was established to predict GWL in the phreatic aquifer (Aq0) and the first confined aquifer (AqI). The equivalent hydraulic conductivity (<i>K</i><sub>eq</sub>) of model elements containing subsurface structures, calculated by the effective medium theory, was applied to the model. The predicted GWL fitted the monitored value in Aq0 well. Additional subsurface structures were added to the model to analyze the influence of the distribution type and the proportion (%) of the volume of subsurface structures that occupy the aquifer (<i>V</i><sub>u</sub>). Four scenarios with different distribution types (concentrated, subconcentrated, subscattered, and scattered) and ten scenarios with <i>V</i><sub>u</sub> varying from 5 to 50%, were analyzed. In all scenarios, the regional average GWL in AqI increased compared to the actual conditions because of the decrease in <i>K</i><sub>eq</sub> and the blockage effect on groundwater flow. The influence of scattered distribution on the regional GWL distribution was the smallest, and the subscattered distribution resulted in the most nonuniform GWL redistribution. The blockage effect of the subsurface structures gradually increased with increasing <i>V</i><sub>u</sub>. The increasing rate of Δ<i>L</i><sub>av</sub> (difference in regional average GWL between the predicted and actual scenarios) becomes considerable when<i> V</i><sub>u</sub> is ~29%. Hence, the projected increase in volume of subsurface structures in AqI under the assumed subscattered distribution is suggested to be <29%.</p>\",\"PeriodicalId\":13013,\"journal\":{\"name\":\"Hydrogeology Journal\",\"volume\":\"18 1\",\"pages\":\"\"},\"PeriodicalIF\":2.4000,\"publicationDate\":\"2024-05-25\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Hydrogeology Journal\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://doi.org/10.1007/s10040-024-02796-w\",\"RegionNum\":3,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"GEOSCIENCES, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Hydrogeology Journal","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.1007/s10040-024-02796-w","RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"GEOSCIENCES, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
摘要
地下结构对地下水渗流的阻挡作用对地下水位(GWL)具有长期影响。根据中国上海某城区地下结构的实际分布情况,建立了有限差分法(FDM)模型,用于预测透水含水层(Aq0)和第一承压含水层(AqI)的地下水位。模型采用了有效介质理论计算的包含地下结构的模型元素的等效导水性(Keq)。预测的 GWL 与 Aq0 的监测值非常吻合。在模型中加入了更多的地下结构,以分析地下结构的分布类型和占含水层体积的比例(%)(Vu)的影响。分析了不同分布类型(集中、次集中、次分散和分散)的四种情景和 Vu 值从 5%到 50%不等的十种情景。在所有方案中,由于 Keq 的下降和对地下水流的阻塞效应,AqI 中的区域平均 GWL 与实际情况相比都有所增加。分散分布对区域 GWL 分布的影响最小,次分散分布导致的 GWL 再分布最不均匀。随着 Vu 的增加,地下结构的阻塞效应逐渐增强。当 Vu 约为 29% 时,ΔLav(预测方案与实际方案之间的区域平均 GWL 差值)的增加率变得相当大。因此,在假定的次散射分布下,AqI 中次表层结构体积的预计增加率为 <29%。
Long-term effects of subsurface structures on groundwater level in a typical urban area of Shanghai, China
The effect of subsurface structures in blocking groundwater seepage has a long-term influence on groundwater level (GWL). A finite difference method (FDM) model considering the actual distribution of subsurface structures in an urban area of Shanghai (China) was established to predict GWL in the phreatic aquifer (Aq0) and the first confined aquifer (AqI). The equivalent hydraulic conductivity (Keq) of model elements containing subsurface structures, calculated by the effective medium theory, was applied to the model. The predicted GWL fitted the monitored value in Aq0 well. Additional subsurface structures were added to the model to analyze the influence of the distribution type and the proportion (%) of the volume of subsurface structures that occupy the aquifer (Vu). Four scenarios with different distribution types (concentrated, subconcentrated, subscattered, and scattered) and ten scenarios with Vu varying from 5 to 50%, were analyzed. In all scenarios, the regional average GWL in AqI increased compared to the actual conditions because of the decrease in Keq and the blockage effect on groundwater flow. The influence of scattered distribution on the regional GWL distribution was the smallest, and the subscattered distribution resulted in the most nonuniform GWL redistribution. The blockage effect of the subsurface structures gradually increased with increasing Vu. The increasing rate of ΔLav (difference in regional average GWL between the predicted and actual scenarios) becomes considerable when Vu is ~29%. Hence, the projected increase in volume of subsurface structures in AqI under the assumed subscattered distribution is suggested to be <29%.
期刊介绍:
Hydrogeology Journal was founded in 1992 to foster understanding of hydrogeology; to describe worldwide progress in hydrogeology; and to provide an accessible forum for scientists, researchers, engineers, and practitioners in developing and industrialized countries.
Since then, the journal has earned a large worldwide readership. Its peer-reviewed research articles integrate subsurface hydrology and geology with supporting disciplines: geochemistry, geophysics, geomorphology, geobiology, surface-water hydrology, tectonics, numerical modeling, economics, and sociology.