Comparative Study of Groundwater-Induced Subsidence for London and Delhi Using PSInSAR

Groundwater variation can cause land-surface movement, which in turn can cause significant and recurrent harm to infrastructure and the water storage capacity of aquifers. The capital cities in the England (London) and India (Delhi) are witnessing an ever-increasing population that has resulted in excess pressure on groundwater resources. Thus, monitoring groundwater-induced land movement in both these cities is very important in terms of understanding the risk posed to assets. Here, Sentinel-1 C-band radar images and the persistent scatterer interferometric synthetic aperture radar (PSInSAR) methodology are used to study land movement for London and National Capital Territory (NCT)-Delhi from October 2016 to December 2020. The land movement velocities were found to vary between −24 and +24 mm/year for London and between −18 and +30 mm/year for NCT-Delhi. This land movement was compared with observed groundwater levels, and spatio-temporal variation of groundwater and land movement was studied in conjunction. It was broadly observed that the extraction of a large quantity of groundwater leads to land subsidence, whereas groundwater recharge leads to uplift. A mathematical model was used to quantify land subsidence/uplift which occurred due to groundwater depletion/rebound. This is the first study that compares C-band PSInSAR-derived land subsidence response to observed groundwater change for London and NCT-Delhi during this time-period. The results of this study could be helpful to examine the potential implications of ground-level movement on the resource management, safety, and economics of both these cities.

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

10.5194/egusphere-egu21-3402 ◽

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

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.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.

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Monitoring groundwater depletion in Iran from space: results from gravity and InSAR observations

10.5194/egusphere-egu2020-17885 ◽

2020 ◽

Author(s):

Mahmud Haghshenas Haghighi ◽

Mahdi Motagh

Keyword(s):

Spatial Resolution ◽

Land Subsidence ◽

Management Practices ◽

Average Rate ◽

Groundwater Resources ◽

Arid Environment ◽

Ground Subsidence ◽

Groundwater Depletion ◽

Industrial Sectors ◽

Groundwater Consumption

Iran is located in a semi-arid to arid environment and is highly dependent on its groundwater resources for development in its agricultural and industrial sectors. In many aquifers across the country, unsustainable groundwater extraction in the past few decades caused severe groundwater level decline, at locations exceeding 20 m. The country is divided into six major basins. However, neither the water consumption nor renewable water resources are distributed evenly. Quantitative assessment of the groundwater situation in different basins is a piece of crucial information for improving management practices. In this study, we use satellite observations to assess the groundwater situation across Iran.We observe the terrestrial water storage (TWS) from Satellite gravimetry measurements of Gravity Recovery And Climate Experiment (GRACE). These observations provide a country-scale picture of groundwater variations at a coarse spatial resolution of 500 km. In all six basins, TWS declines during the 15 year lifetime of GRACE from 2002 until 2017. In total, the Equivalent Water Height (EWH) declines as much as approximately 10 cm during this period. Although part of this decline is caused by other components such as surface water or soil moisture, groundwater decline is responsible for the major part.The compaction of aquifers resulted from the over-extraction of groundwater can be observed as land subsidence on the surface. We analyze ground subsidence for the whole Iran using Interferometric Synthetic Aperture Radar (InSAR) observations of the Copernicus Sentinel-1 satellite and present the first detailed map of compacting aquifers across the country at a high spatial resolution of 100 m. The average rate of displacement, exceeding 30 cm/yr in some areas, reveals hundreds of aquifers across the country are suffering unsustainable groundwater consumption. The distribution of subsidence basins is significantly correlated with the distribution of agricultural regions.To obtain information on the sustainability of groundwater consumption, we separate the time series of land subsidence into two parts: the short term part as elastic/recoverable component and the long-term part as inelastic/irrecoverable. The ratio between elastic and inelastic elements provides quantitative measurements of aquifer health. Combining the Sentinel-1 subsidence measurements with GRACE observations of groundwater variations gives us new details on how the groundwater is consumed across different basins in the country. The results can have essential implications on the more sustainable management of groundwater resources.

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

Geosciences ◽

10.3390/geosciences9050223 ◽

2019 ◽

Vol 9 (5) ◽

pp. 223 ◽

Cited By ~ 2

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.

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Towards aquifer deformation models integrating SAR remote sensing: preliminary land subsidence results using GEP tools

10.5194/egusphere-egu21-12806 ◽

2021 ◽

Author(s):

Guadalupe Bru ◽

Pablo Ezqerro ◽

Carolina Guardiola-Albert ◽

Marta Béjar-Pizarro ◽

Gerardo Herrera ◽

...

Keyword(s):

Remote Sensing ◽

Drinking Water ◽

Groundwater Flow ◽

Land Subsidence ◽

Surface Deformation ◽

Salt Water ◽

Groundwater Resources ◽

Groundwater Depletion ◽

Web Tool ◽

Aquifer Systems

Groundwater is a critical resource that provides fresh drinking water to at least 50% of the global population and accounts for 43% of all of the water used for irrigation (Siebert et al., 2010; UNESCO, 2012). A main consequence of groundwater depletion in overexploited aquifers is land subsidence, which ensues other impacts, such as increasing flooding risk (specially in coastal areas), damages to infrastructures and reduction of storage capacity in aquifer systems. Aquifer deformation and groundwater flow models are essential to design sustainable management strategies. In this context, A-DInSAR techniques provide valuable surface displacement data to understand the deformational behaviour of the aquifer and to characterise its properties.RESERVOIR project, which is part of the PRIMA programme supported by the European Union, aims to provide new products and services for a sustainable groundwater management model to be developed and tested in four water-stressed Mediterranean pilot sites. Each of them is representative of a different aquifer system flow scheme. They are located in Italy (coastal aquifer of Comacchio), Spain (Alto Guadalent&#237;n Basin), Turkey (Gediz River Basin) and Jordan (Azraq Wetland Reserve). The water usages of these aquifers are irrigation, drinking water and/or power generation. Each site is prone to different issues such as land subsidence, salt water intrusion, water pollution, over-exploitation and insufficient recharge.One of the primary objectives of the project is the use of advanced satellite-based Earth Observation (EO) techniques for the hydrogeological characterization and their integration into numerical groundwater flow and geomechanical models. This will lead to improve the knowledge about the current capacity to store water and the future response of aquifer systems to natural and human-induced stresses. Free Sentinel-1 SAR acquisitions available at the Copernicus Open Access Hub will be used to perform A-DInSAR processing in representative areas of each pilot site. Additionally, the InSAR processing tools of the Geohazards Exploitation Platform (GEP) funded by the European Space Agency, will be used for a first assessment of ground deformation. In this work we present the preliminary results obtained with Sentinel-1 images using the P-SBAS web tool on GEP (De Luca et al., 2015) at the four pilot sites.&#160;De Luca, C., Cuccu, R., Elefante, S., Zinno, I., Manunta, M., Casola, V., Rivolta, G., Lanari, R., and Casu, F., 2015, An on-demand web tool for the unsupervised retrieval of earth&#8217;s surface deformation from SAR data: The P-SBAS service within the ESA G-POD environment: Remote Sensing, v. 7, no. 11, p. 15630-15650.Siebert, S., Burke, J., Faures, J.-M., Frenken, K., Hoogeveen, J., D&#246;ll, P., and Portmann, F. T., 2010, Groundwater use for irrigation&#8212;a global inventory: Hydrology and earth system sciences, v. 14, no. 10, p. 1863-1880.UNESCO, 2012, World&#8217;s Groundwater Resources Are Suffering from Poor Governance, UNESCO Publishing: Paris, France, UNESCO Publishing.

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Land Subsidence in Delhi, India investigated using Sentinel-1 InSAR measurements

10.5194/egusphere-egu2020-21138 ◽

2020 ◽

Author(s):

Shagun Garg ◽

Mahdi Motagh ◽

Indu Jayaluxmi

Keyword(s):

Land Subsidence ◽

Land Surface ◽

Surface Deformation ◽

Field Measurements ◽

Groundwater Depletion ◽

National Capital Region ◽

Rapid Urbanization ◽

In Situ Data ◽

Persistent Scatterers ◽

The Government

Groundwater induced land subsidence is a growing problem worldwide and has been documented in places like Mexico, Jakarta, Tehran, and China. India is the largest user of groundwater and pumps more than the USA and China combined. The National capital region(NCR) of India, due to rapid urbanization and illegal extraction, is facing severe groundwater depletion of the order of 0.5m-2m per year and is declared as a critical zone by the government of India. The looming crisis of groundwater depletion and supporting hydrogeology makes this region prone to land surface deformation.Monitoring subsidence by conventional methods such as extensometers, leveling, hydrogeology modeling, and GPS requires precise field measurements and are time-consuming. With the advent of Interferometry, monitoring deformation precisely from the microwave sensors onboard satellite is possible. In our study, we demonstrate the result of the Persistent Scatterer InSAR (PS-InSAR) technique to monitor the subsidence in the Delhi NCR region using Sentinel -1 Interferometric wide swath (IW) mode. Descending pass datasets are used to identify the PSs over the study area. Fifty-six differential interferograms from Aug 2016 to Sep 2018 are formed after removing flat earth and topographic phase using SRTM 30m DEM. The PS-InSAR processing is done using Stanford Method for Persistent Scatterers (StaMPS), where an amplitude threshold index of 0.4 is selected for Initial PS candidate. The PS points are the stable targets which do not decorrelate much over time. &#160;The deformation is calculated for all these PS points and a time series, and hence a velocity map is formed.The rate of deformation in Southwest Delhi is found to be approximately 15 cm/year (max) in the radar line of sight direction. The in-situ data provided by the Central groundwater board (CGWB) India is not consistent and has many gaps. However, after applying Spatio-temporal interpolation, it follows the decreasing trend of Land subsidence which suggests that the groundwater extraction is the major cause for the subsidence in the southwest region of NCR during the observed period i.e., from 2016 -2018.

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Analysis of the Deformation Behavior and Sinkhole Risk in Kerdabad, Iran Using the PS-InSAR Method

Remote Sensing ◽

10.3390/rs13142696 ◽

2021 ◽

Vol 13 (14) ◽

pp. 2696

Author(s):

Mahdi Khoshlahjeh Azar ◽

Amir Hamedpour ◽

Yasser Maghsoudi ◽

Daniele Perissin

Keyword(s):

Time Series ◽

Land Surface ◽

Human Life ◽

Groundwater Depletion ◽

Driving Mechanism ◽

Radar Images ◽

Persistent Scatterers ◽

Gradual Process ◽

Hamedan Province ◽

The One

The unexpected collapse of land surface due to subsidence is one of the most significant geohazards that threatens human life and infrastructure. Kabudrahang and Famenin are two Iranian plains experiencing several sinkholes due to the characteristics of the underground soil layers and extreme groundwater depletion. In this study, space-based Synthetic Aperture Radar images are used to investigate the ground displacement behavior to examine the feasibility of Sentinel-1 data in detecting precursory deformation proceeding before the sinkhole formation. The selected sinkhole occurred in August 2018 in the vicinity of Kerdabad village in Hamedan province with a 40 m diameter and depth of ~40 m. Time series of the European constellation Sentinel-1 data, spanning from January 2015 to August 2018, is analyzed, and the results revealed a 3 cm annual subsidence (–3cm/year) along with the line-of-sight direction. Time-series analysis demonstrated that the driving mechanism of the sinkhole formation had a gradual process. Displacement of persistent scatterers (PSs) near the cave area had an acceleration by approaching the sinkhole formation date. In contrast, other areas that are far from the cave area show linear subsidence behavior over time. Additionally, the one-kilometer deformation profile over the cave area indicates a high subsidence rate precisely at the location where the sinkhole was formed later on 20 August 2018.

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Groundwater resources of Eastern Libya (Cyrenaica)

Annual report - Society for Libyan Studies ◽

10.1017/s0263718900000789 ◽

1977 ◽

Vol 8 ◽

pp. 41-44 ◽

Cited By ~ 2

Author(s):

E. P. Wright

Keyword(s):

Water Table ◽

Land Surface ◽

Groundwater Resources ◽

Ground Surface ◽

Sedimentary Basins ◽

Ground Level ◽

Annual Rainfall ◽

Uniform Structure ◽

Flow Systems ◽

Sirte Basin

Cyrenaica, excluding the Jebel Akhdar, forms part of the Libyan Sahara. It is a true desert with a mean annual rainfall generally less than 20 mm, and a land surface of sand, gravel or rock, largely devoid of vegetation (Plate 1). Yet a few thousand years ago, the Libyan Sahara, as elsewhere in North Africa, enjoyed an abundant rainfall and supported a varied flora and fauna as can be seen from pre-historic rock paintings. The abundant rainfall filled huge subterranean reservoirs which since then have been slowly draining to the Mediterranean Sea or low lying sabkhats and inland lakes. In consequence of the moderate relief of the Sahara and the wide regional extent and uniform structure of the sedimentary basins which form the reservoirs, the groundwater bodies occur in huge flow systems which may extend over several hundreds of miles. The reservoirs' thicknesses vary but the two most important series, the Continental Intercalaire or Nubian, and the Continental Terminal of mid-Tertiary to recent age, frequently exceed 3000 feet. Two major flow systems occur in Cyrenaica, in the Sirte and Kufra basins (Fig.1).Until oil was discovered in the late nineteen fifties, groundwater development in Cyrenaica was mainly concentrated in coastal areas where the prevailing rainfall is sufficient to permit some recharge, and in a few interior scattered oases — Giarabub, Jalo-Augila, Kufra and Tazerbo, where the ground surface lies close to the upper phreatic (water table) surface of regional groundwater systems.Oil exploration requires fairly large supplies of water for the main drilling operations. During exploration in the Sirte basin it was discovered that water of variable quality could be found virtually anywhere at moderate depths between 100 and 500 feet below ground level. Oil company practice to obtain temporary water supplies is to drill two or three simply constructed water wells to a few hundred feet below the water table, and to pump by air lift. The wells are subsequently capped, when no longer required.

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Detection and measurement of land subsidence and uplift using interferometric synthetic aperture radar, San Diego, California, USA, 2016–2018

Proceedings of the International Association of Hydrological Sciences ◽

10.5194/piahs-382-45-2020 ◽

2020 ◽

Vol 382 ◽

pp. 45-49

Author(s):

Justin T. Brandt ◽

Michelle Sneed ◽

Wesley R. Danskin

Keyword(s):

Synthetic Aperture Radar ◽

Land Subsidence ◽

Land Surface ◽

San Diego ◽

The United States ◽

Synthetic Aperture ◽

United States Geological Survey ◽

Interferometric Synthetic Aperture Radar ◽

Groundwater Levels ◽

Aperture Radar

Abstract. Land subsidence associated with groundwater-level declines is stipulated as an “undesirable effect” in California's Sustainable Groundwater Management Act (SGMA), and has been identified as a potential issue in San Diego, California, USA. The United States Geological Survey (USGS), the Sweetwater Authority, and the City of San Diego, undertook a cooperative study to better understand the hydromechanical response of the coastal aquifer system using Interferometric Synthetic Aperture Radar (InSAR) techniques. Three periods of interest were analyzed for this study that correspond to the periods before and after two substantial changes were made to the location and volume of pumpage: (1) April–August 2016 when groundwater levels and land surface elevation were relatively stable during normal pumping, (2) September 2016–May 2017 when groundwater levels recovered and the land surface uplifted during a period of substantially reduced pumping, (3) June 2017–October 2018 when groundwater levels declined and land subsidence occurred when pumpage resumed and expanded to new wells. Spatial and temporal characterization of the hydromechanical response to changes in pumpage is important for managing land subsidence. Further study using InSAR techniques, especially when combined with ground-based geodetic and monitoring-well networks, will provide water managers information to help effectively manage groundwater resources as stipulated in the SGMA.

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State of the Art and Recent Advancements in the Modelling of Land Subsidence Induced by Groundwater Withdrawal

Water ◽

10.3390/w12072051 ◽

2020 ◽

Vol 12 (7) ◽

pp. 2051 ◽

Cited By ~ 2

Author(s):

Artur Guzy ◽

Agnieszka Malinowska

Keyword(s):

Land Subsidence ◽

Land Surface ◽

Flow Direction ◽

Water Pressure ◽

Economic Effects ◽

Aquifer System ◽

Damage Costs ◽

Fundamental Relationship ◽

Spatio Temporal ◽

Satellite Radar

Land subsidence is probably one of the most evident environmental effects of groundwater pumping. Globally, freshwater demand is the leading cause of this phenomenon. Land subsidence induced by aquifer system drainage can reach total values of up to 14.5 m. The spatial extension of this phenomenon is usually extensive and is often difficult to define clearly. Aquifer compaction contributes to many socio-economic effects and high infrastructure-related damage costs. Currently, many methods are used to analyze aquifer compaction. These include the fundamental relationship between groundwater head and groundwater flow direction, water pressure and aquifer matrix compressibility. Such solutions enable satisfactory modelling results. However, further research is needed to allow more efficient modelling of aquifer compaction. Recently, satellite radar interferometry (InSAR) has contributed to significant progress in monitoring and determining the spatio-temporal land subsidence distributions worldwide. Therefore, implementation of this approach can pave the way to the development of more efficient aquifer compaction models. This paper presents (1) a comprehensive review of models used to predict land surface displacements caused by aquifer drainage, as well as (2) recent advances, and (3) a summary of InSAR implementation in recent years to support the aquifer compaction modelling process.

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

Proceedings of the International Association of Hydrological Sciences ◽

10.5194/piahs-372-23-2015 ◽

2015 ◽

Vol 372 ◽

pp. 23-27 ◽

Cited By ~ 4

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.

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