scholarly journals Spatial-temporal variation of groundwater and land subsidence evolution in Beijing area

2015 ◽  
Vol 372 ◽  
pp. 7-11
Author(s):  
K. Lei ◽  
Y. Luo ◽  
B. Chen ◽  
M. Guo ◽  
G. Guo ◽  
...  
Keyword(s):  
Temporal Variation ◽  
Land Subsidence ◽  
Groundwater Level ◽  
Meteorological Data ◽  
Rapid Expansion ◽  
Persistent Scatterer Interferometry ◽  
Systematic Analysis ◽  
Groundwater Levels ◽  
Level Data ◽  
Regional Land

Abstract. Precipitation is the main recharge source of groundwater in the plain of Beijing, China. Rapid expansion of urbanization has resulted in increased built-up area and decreased amount of effective recharge of precipitation to groundwater, indirectly leading to the long-term over-exploitation of groundwater, and induced regional land subsidence. Based on the combination of meteorological data, groundwater level data, interferometric synthetic aperture radar (InSAR; specifically persistent scatterer interferometry, PSI), geographic information system (GIS) spatial analysis method and rainfall recharge theory, this paper presents a systematic analysis of spatial-temporal variation of groundwater level and land subsidence evolution. Results show that rainfall has been decreasing annually, while the exploitation of groundwater is increasing and the groundwater level is declining, which is has caused the formation and evolution of land subsidence. Seasonal and interannual variations exist in the evolution of land subsidence; the subsidence is uneven in both spatial and temporal distribution. In 2011, at the center of mapped subsidence the subsidence rate was greater than 120 mm a−1. The results revealed good correlation between the spatial distribution of groundwater level declines and subsidence. The research results show that it is beneficial to measure the evolution of land subsidence to dynamic variations of groundwater levels by combining InSAR or PSI, groundwater-level data, and GIS. This apprpach provides improved information for environmental and hydrogeologic research and a scientific basis for regional land subsidence control.

Detecting land deformation due to groundwater changes with InSAR observations - the case of the island of Gotland, Sweden

2021 ◽  
Author(s):  
Mehdi Darvishi ◽  
Fernando Jaramillo
Keyword(s):  
Land Subsidence ◽  
Groundwater Level ◽  
Ground Deformation ◽  
Soil Depth ◽  
Ground Surface ◽  
Groundwater Depletion ◽  
Groundwater Levels ◽  
Small Baseline Subset ◽  
Small Baseline ◽  
The Baltic

<p>In the recent years, southern Sweden has experienced drought conditions during the summer with potential risks of groundwater shortages. One of the main physical effects of groundwater depletion is land subsidence, a geohazard that potentially damages urban infrastructure, natural resources and can generate casualties. We here investigate land subsidence induced by groundwater depletion and/or seasonal variations in Gotland, an agricultural island in the Baltic Sea experiencing recent hydrological droughts in the summer. Taking advantage of the multiple monitoring groundwater wells active on the island, we explore the existence of a relationship between groundwater fluctuations and ground deformation, as obtained from Interferometric Synthetic Aperture Radar (InSAR). The aim in the long-term is to develop a high-accuracy map of land subsidence with an appropriate temporal and spatial resolution to understand groundwater changes in the area are recognize hydroclimatic and anthropogenic drivers of change.</p><p>We processed Sentinel-1 (S1) data, covering the time span of 2016-2019, by using the Small BAseline Subset (SBAS) to process 119 S1-A/B data (descending mode). The groundwater level of Nineteen wells distributed over the Gotland island were used to assess the relationship between groundwater depletion and the detected InSAR displacement. In addition to that, the roles of other geological key factors such as soil depth, ground capacity in bed rock, karstification, structure of bedrock and soil type in occurring land subsidence also investigated. The findings showed that the groundwater level in thirteen wells with soil depths of less than 5 meters correlated well with InSAR displacements. The closeness of bedrock to ground surface (small soil depth) was responsible for high coherence values near the wells, and enabled the detection land subsidence. The results demonstrated that InSAR could use as an effective monitoring system for groundwater management and can assist in predicting or estimating low groundwater levels during summer conditions.</p>

scholarly journals Groundwater Level Change Management on Control of Land Subsidence Supported by Borehole Extensometer Compaction Measurements in the Houston-Galveston Region, Texas

Geosciences ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 223 ◽  
Author(s):  
Yi Liu ◽  
Jiang Li ◽  
Zheng N. Fang
Keyword(s):  
Change Management ◽  
Land Subsidence ◽  
Groundwater Level ◽  
Land Surface ◽  
Groundwater Withdrawal ◽  
Overburden Pressure ◽  
Groundwater Levels ◽  
Level Change ◽  
Aquifer Systems ◽  
Groundwater Level Change

As much as 3.05 m of land subsidence was observed in 1979 in the Houston-Galveston region as a result primarily of inelastic compaction of aquitards in the Chicot and Evangeline aquifers between 1937 and 1979. The preconsolidation pressure heads for aquitards within these two aquifers were continuously updated in response to lowering groundwater levels, which in turn was caused by continuously increasing groundwater withdrawal rates from 0.57 to 4.28 million m3/day. This land subsidence occurred without any management of changes in groundwater levels. However, the management of recovering groundwater levels from 1979 to 2000 successfully decreased inelastic compaction from about 40 mm/yr in the early 1980s to zero around 2000 through decreasing groundwater withdrawal rates from 4.3 to 3.0 million m3/day. The inelastic consolidation that had existed for about 63 years roughly from 1937 to 2000 caused a land subsidence hazard in this region. Some rebounding of the land surface was achieved from groundwater level recovering management. It is found in this paper that subsidence of 0.08 to 8.49 mm/yr owing to a pseudo-constant secondary consolidation rate emerged or tended to emerge at 13 borehole extensometer station locations while the groundwater levels in the two aquifers were being managed. It is considered to remain stable in trend since 2000. The subsidence due to the secondary consolidation is beyond the control of any groundwater level change management schemes because it is caused by geo-historical overburden pressure on the two aquifers. The compaction measurements collected from the 13 extensometers since 1971 not only successfully corroborate the need for groundwater level change management in controlling land subsidence but also yield the first empirical findings of the occurrence of secondary consolidation subsidence in the Quaternary and Tertiary aquifer systems in the Houston-Galveston region.

scholarly journals Study on compaction mechanism of overconsolidated soil and critical groundwater level in Cangzhou

2019 ◽  
Vol 79 ◽  
pp. 02010
Author(s):  
Yunlong Wang ◽  
Ye Chen ◽  
Haipeng Guo ◽  
Xisheng Zang
Keyword(s):  
Stress Analysis ◽  
Water Level ◽  
Water Resource ◽  
Land Subsidence ◽  
Groundwater Level ◽  
Groundwater Exploitation ◽  
Groundwater Levels ◽  
Good Consistency ◽  
Long Time ◽  
Groundwater Overexploitation

Cangzhou area is facing increasingly serious land subsidence problem caused by groundwater overexploitation during a long time. In order to make effectively use of water resource and to limit the development of subsidence, it is necessary to establish the warning critical water level, that is, the subsidence rate will increase significantly as the water level depths exceeds the critical groundwater levels. In this paper, the 3rd aquifer group, the main groundwater exploitation layer, has been taken as a research object. The critical water level is calculated by stress analysis, and then determined by the correlation between the monitoring data of groundwater levels and subsidence. The calculated results indicate good consistency.

scholarly journals Statistical and Numerical Assessments of Groundwater Resource Subject to Excessive Pumping: Case Study in Southwest Taiwan

Water ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 360 ◽  
Author(s):  
Dong-Sin Shih ◽  
Chia-Jeng Chen ◽  
Ming-Hsu Li ◽  
Cheng-Shin Jang ◽  
Che-Min Chang ◽  
...  
Keyword(s):  
Time Series ◽  
Numerical Experiment ◽  
Land Subsidence ◽  
Coastal Area ◽  
Alluvial Plain ◽  
Numerical Techniques ◽  
Groundwater Levels ◽  
Remote Locations ◽  
Regional Land

Groundwater, a salient water resource in Taiwan, has been subject to incessant and excessive pumping, inducing serious regional land subsidence and seawater intrusion. This study aims at assessing how excessive pumping impacts groundwater variations over the Pingtung Alluvial Plain (PAP) in Southwest Taiwan using both statistical and numerical techniques. We apply nonparametric methods to analyze the changing point and annual trend in various hydro-meteorological time series (e.g., rainfall, temperature, and groundwater levels (GLs)). Afterwards, we employ an integrated surface-subsurface model referred to as WASH123D to simulate GLs under the pumping-free scenario; any discrepancies identified between simulated and observed GLs could be an indicator of unregulated/illegal pumping. We find that annual GLs exhibit a significant increasing (decreasing) trend in the western (eastern) PAP. Our numerical experiment reveals diverging trends in simulated and observed GLs, mostly at the downstream of all the major tributaries, suggesting the consequence of unregulated/illegal pumping. Furthermore, upstream pumping may reduce lateral flow towards the downstream coastal area, triggering land subsidence in remote locations.

scholarly journals Land subsidence in the San Joaquin Valley, California, USA, 2007–2014

2015 ◽  
Vol 372 ◽  
pp. 23-27 ◽  
Author(s):  
M. Sneed ◽  
J. T. Brandt
Keyword(s):  
Land Use ◽  
Surface Water ◽  
Land Subsidence ◽  
Groundwater Level ◽  
Land Surface ◽  
Land Use Changes ◽  
San Joaquin Valley ◽  
Flood Hazards ◽  
Groundwater Levels ◽  
Measured Rate

Abstract. Rapid land subsidence was recently measured using multiple methods in two areas of the San Joaquin Valley (SJV): between Merced and Fresno (El Nido), and between Fresno and Bakersfield (Pixley). Recent land-use changes and diminished surface-water availability have led to increased groundwater pumping, groundwater-level declines, and land subsidence. Differential land subsidence has reduced the flow capacity of water-conveyance systems in these areas, exacerbating flood hazards and affecting the delivery of irrigation water. Vertical land-surface changes during 2007–2014 were determined by using Interferometric Synthetic Aperture Radar (InSAR), Continuous Global Positioning System (CGPS), and extensometer data. Results of the InSAR analysis indicate that about 7600 km2 subsided 50–540 mm during 2008–2010; CGPS and extensometer data indicate that these rates continued or accelerated through December 2014. The maximum InSAR-measured rate of 270 mm yr−1 occurred in the El Nido area, and is among the largest rates ever measured in the SJV. In the Pixley area, the maximum InSAR-measured rate during 2008–2010 was 90 mm yr−1. Groundwater was an important part of the water supply in both areas, and pumping increased when land use changed or when surface water was less available. This increased pumping caused groundwater-level declines to near or below historical lows during the drought periods 2007–2009 and 2012–present. Long-term groundwater-level and land-subsidence monitoring in the SJV is critical for understanding the interconnection of land use, groundwater levels, and subsidence, and evaluating management strategies that help mitigate subsidence hazards to infrastructure while optimizing water supplies.

scholarly journals Numerical Simulation of Deep Thermal Groundwater Exploitation in the Beijing Plain Area

Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1494 ◽  
Author(s):  
Zhongping Xu ◽  
Xun Zhou ◽  
Ruige Chen ◽  
Ye Shen ◽  
Ziqi Shang ◽  
...  
Keyword(s):  
Groundwater Level ◽  
Initial Water ◽  
Groundwater Exploitation ◽  
Groundwater Levels ◽  
Plain Area ◽  
Thermal Groundwater ◽  
Beijing Plain ◽  
Level Data ◽  
Water Level Data ◽  
3D Unsteady Flow

Thermal groundwater is relatively abundant in the deep-seated bedrock underlying the Beijing plain area. The main geothermal reservoir is composed of dolomites of the Wumishan Group of the Meso–Neoproterozic Jixian System. The thermal groundwater has been developed and utilized since the 1970s and significant declines in groundwater levels were observed. A 3D unsteady flow model of an anisotropic karst-fissure aquifer based on the equivalent continuum is used to describe the flow of thermal groundwater and heat transport. The heat transportation is described by the governing equation including convection and dispersion. The simulation of this paper aims to solve such problems as uneven distribution and thinness of the aquifer, insufficient initial monitoring data, and poor knowledge of the properties of the horizontal boundary. They are solved by considering vertical stratification of the aquifer with equal thickness, replacing initial water level data by surface elevation, and choosing natural boundary far away from the exploitation areas. Through a trial–error procedure, the simulated and measured groundwater level and temperature in the simulation period are well fitted. Three exploitation schemes are proposed to predict the spatial and temporal changes in groundwater level and temperature of the thermal groundwater in the study area. The prediction results show that the reinjection can effectively slow the decline in the thermal groundwater levels. Except for the Dongnanchengqu, Xiaotangshan, and Liangxiang subgeothermal fields, the other six subgeothermal fields have the potential for further development of thermal groundwater.

Mapping and analyzing land subsidence for Tehran using Sentinel-1 SAR and GPS and geological data

2021 ◽  
Author(s):  
Soheil Rajabi Baniani ◽  
Ling Chang ◽  
Yasser Maghsoudi
Keyword(s):  
Land Subsidence ◽  
Structural Damage ◽  
High Rate ◽  
Double Difference ◽  
Economic Losses ◽  
Driving Mechanism ◽  
Persistent Scatterer Interferometry ◽  
Groundwater Levels ◽  
Land Deformation ◽  
Gps Observations

<p><span>Tehran, as a megacity in Iran, is exposed to a high rate of land deformation. Recent research shows average land deformation speed is up to 39.9 mm/year in southeast plain (from 2014 to 2017) and groundwater extraction in Tehran plain for agricultural and industrial demands is the most probable driving mechanism. It is undisputed that infrastructure and structure in Tehran are continuously under threat by such rapid land subsidence, and this subsidence may also lead to significant economic losses such as structural damage and high maintenance costs for roads, railways, dikes, pipelines, and buildings. Therefore, when, where and why the subsidence did/does occur has to be closely monitored and analysed considering future planning and the importance of infrastructure and structure damage, which has a profound effect on human activities. This study attempts to use Sentinel 1 SAR data to map land subsidence in Tehran and validate the results by using GPS data.</span></p><p><span>We implemented the standard persistent scatterer interferometry (PSI) approach with the customized parameter configuration, for Tehran with an area of ​​about 1600 km<sup>2</sup>. 52 Sentinel 1A (C-band) dataset acquired between 2018 and 2019 were collected. There were 1,746,317 PS measurement points generated. The PSI results illustrate that the maximum loss of elevation over the time period did amount to 11.7 cm/year.  </span></p><p><span>We used the GPS observations between 1/1/2018 and 27/10/2019, from the two GPS stations GPS-m318 (35.64 N, 51.29 E), GPS-m020 (35.58 N, 51.42 E) to evaluate the PSI deformation results. We found that the maximum and minimum double difference between GPSs and PSs were 0.0536 m, 0.0015 m respectively; moreover, the corresponding histogram shows that most of the double-difference values are in the interval of [-0.01 0.01] m, and the RMSE is 0.011 m. Besides, we also applied the velocity comparison of double-differenced GPS and PS, which shows that the PS measurements matched well with the GPS observations.</span></p><p><span>By comparing the water table variations and PSI-derived land deformation, we found that the groundwater withdraw could be a major driving mechanism but the variation in soil type also plays an important role. For instance, although the groundwater levels (Xutm = 503498, Yutm = 3948916) has decreased by approximately 13m from 2012 to 2017 at the place of Andisheh-Jadid, no subsidence was detected possibly due to the presence of well grade layers at that location.</span></p>

scholarly journals The Secondary Consolidation (Creep) due to Geohistorical Overburden Pressure in the Houston-Galveston Region, Texas

2020 ◽  
Vol 382 ◽  
pp. 315-320
Author(s):  
Yi Liu ◽  
Jiang Li ◽  
Zheng N. Fang ◽  
Mojtaba Rashvand ◽  
Tranell Griffin
Keyword(s):  
Land Subsidence ◽  
Groundwater Level ◽  
Land Surface ◽  
Surface Subsidence ◽  
Water Levels ◽  
Groundwater Withdrawal ◽  
Overburden Pressure ◽  
Groundwater Levels ◽  
Consolidation Rate ◽  
Primary Consolidation

Abstract. The combination of groundwater withdrawal, hydrocarbon extraction, salt-dome movement and faulting have caused widespread subsidence in the Houston-Galveston region (HGR). Subsidence results from primary consolidation consisting of inelastic (nonrecoverable) and elastic (recoverable) compaction caused by subsurface fluid withdrawal and secondary consolidation (creep) over time caused by overburden pressure. Subsidence in the HGR is monitored using borehole extensometers that were installed at 13 locations across Harris and Galveston counties between 1962 and 1980. By 1977, withdrawals from the Chicot and Evangeline aquifers resulted in groundwater-level declines of about 114 and 115 m relative to predevelopment water levels, respectively in parts of Harris County. By 1979, as much as 3 m of land subsidence was estimated to have occurred in localized areas of the HGR. Land subsidence can be hazardous in populated areas because it exacerbates the effects of storm surge and impedes storm-water runoff by decreasing land-surface elevations in areas where water accumulates. To assess aquifer compaction in response to changes in groundwater levels, a bulk land-surface subsidence rate is assumed to be the sum of the primary consolidation rate and the negligibly variable component of overburden pressure referred to as the “pseudo-constant secondary consolidation rate.” From 1931 to 1976, groundwater levels decreased as groundwater withdrawal rates increased from 0.57 to 4.3 million m3 d−1, causing pressure heads in aquitards the Chicot and Evangeline aquifers to continually decline. In response to reductions in groundwater withdrawal rates from 4.3 to 3.0 million m3 d−1 between 1976 and 2001, groundwater levels rebounded, decreasing inelastic compaction rates in some parts of the HGR from as much as about 40 mm yr−1 in the early 1980s to negligible amounts by 2000. Inelastic consolidation from about 1937 to 2000 contributed to land-surface subsidence and its associated effects. Land-surfaces have rebounded in localized areas of the HGR where groundwater levels rebounded significantly. Pseudo-constant secondary consolidation rates were computed at each of the 13 extensometers and ranged from 0.48 to 8.49 mm yr−1 in areas where groundwater levels in the two aquifers were stabilizing. This secondary consolidation subsidence is beyond the control of any groundwater-level management schemes because it is caused by geohistorical overburden pressure on the two aquifers.

scholarly journals Mitigating Land Subsidence in the Coachella Valley, California, USA: An Emerging Success Story

2020 ◽  
Vol 382 ◽  
pp. 809-813
Author(s):  
Michelle Sneed ◽  
Justin T. Brandt
Keyword(s):  
Land Subsidence ◽  
Groundwater Level ◽  
Water Levels ◽  
Mitigation Measures ◽  
Aquifer Recharge ◽  
Domestic Water ◽  
Aquifer System ◽  
Groundwater Levels ◽  
Coachella Valley ◽  
Groundwater Overdraft

Abstract. Groundwater has been a major source of agricultural, municipal, and domestic water supply since the early 1920s in the Coachella Valley, California, USA. Land subsidence, resulting from aquifer-system compaction and groundwater-level declines, has been a concern of the Coachella Valley Water District (CVWD) since the mid-1990s. As a result, the CVWD has implemented several projects to address groundwater overdraft that fall under three categories – groundwater substitution, conservation, and managed aquifer-recharge (MAR). The implementation of three projects in particular – replacing groundwater extraction with surface water from the Colorado River and recycled water (Mid-Valley Pipeline project), reducing water usage by tiered-rate costs, and increasing groundwater recharge at the Thomas E. Levy Groundwater Replenishment Facility – are potentially linked to markedly improved groundwater levels and subsidence conditions, including in some of the historically most overdrafted areas in the southern Coachella Valley. Groundwater-level and subsidence monitoring have tracked the effect these projects have had on the aquifer system. Prior to about 2010, water levels persistently declined, and some had reached historically low levels by 2010. Since about 2010, however, groundwater levels have stabilized or partially recovered, and subsidence has stopped or slowed substantially almost everywhere it previously had been observed; uplift was observed in some areas. Furthermore, results of Interferometric Synthetic Aperture Radar analyses for 1995–2017 indicate that as much as about 0.6 m of subsidence occurred; nearly all of which occurred prior to 2010. Continued monitoring of water levels and subsidence is necessary to inform the CVWD about future mitigation measures. The water management strategies implemented by the CVWD can inform managers of other overdrafted and subsidence-prone basins as they seek solutions to reduce overdraft and subsidence.

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