scholarly journals IoT technology and big data processing for monitoring and analysing land subsidence in Central Taiwan

2020 ◽  
Vol 382 ◽  
pp. 103-109
Author(s):  
Wei-Chia Hung ◽  
Yi-An Chen ◽  
Cheinway Hwang
Keyword(s):  
Land Subsidence ◽  
High Speed ◽  
Large Scale ◽  
Alluvial Fan ◽  
Monitoring Wells ◽  
Multi Temporal ◽  
Multiple Sensor Monitoring ◽  
Large Scale Land ◽  
Central Taiwan ◽  
Subsidence Monitoring

Abstract. Over 1992–2018, groundwater overexploitation had caused large-scale land subsidence in the Choshui River Alluvial Fan (CRAF) in Taiwan. The Taiwan High Speed Railway (THSR) passes through an area of severe subsidence in CRAF, and the subsidence poses a serious threat to its operation. How to effectively monitor land subsidence here has become a major issue in Taiwan. In this paper, we introduce a multiple-sensor monitoring system for land subsidence, including 50 continuous operation reference stations (CORS), multi temporal InSAR (MT-InSAR), a 1000 km levelling network, 34 multi-layer compaction monitoring wells and 116 groundwater monitoring wells. This system can monitor the extent of land subsidence and provide data for studying the mechanism of land subsidence. We use the Internet of Things (IoT) technology to control and manage the sensors and develop a bigdata processing procedure to analyse the monitoring data for the system of sensors. The procedure makes the land subsidence monitoring more efficient and intelligent.

scholarly journals Surface Deformation from Sentinel-1A InSAR: Relation to Seasonal Groundwater Extraction and Rainfall in Central Taiwan

2019 ◽  
Vol 11 (23) ◽  
pp. 2817 ◽  
Author(s):  
Yi-Jie Yang ◽  
Cheinway Hwang ◽  
Wei-Chia Hung ◽  
Thomas Fuhrmann ◽  
Yi-An Chen ◽  
...  
Keyword(s):  
Land Subsidence ◽  
High Speed ◽  
Large Scale ◽  
Surface Deformation ◽  
Dry Season ◽  
Severe Drought ◽  
Groundwater Extraction ◽  
Large Scale Land ◽  
Small Baseline ◽  
Central Taiwan

Extracting groundwater for agricultural, aquacultural, and industrial use in central Taiwan has caused large-scale land subsidence that poses a threat to the operation of the Taiwan High Speed Railway near Yunlin County. We detected Yunlin subsidence using the Sentinel-1A Synthetic Aperture Radar (SAR) by the Small BAseline Subset (SBAS) method from April 2016 to April 2017. We calibrated the initial InSAR-derived displacement rates using GPS measurements and reduced the velocity difference between the two sensors from 15.0 to 8.5 mm/a. In Yunlin’s severe subsidence regions, cumulative displacements from InSAR and GPS showed that the dry-season subsidence contributed 60%–74% of the annual subsidence. The InSAR-derived vertical velocities matched the velocities from leveling to better than 10 mm/a. In regions with few leveling measurements, InSAR increased the spatial resolution of the vertical velocity field and identified two previously unknown subsidence spots over an industrial zone and steel factory. Annual significant subsidence areas (subsidence rate > 30 mm/a) from leveling from 2011 to 2017 increased with the declining dry-season rainfalls, suggesting that the dry-season rainfall was the deciding factor for land subsidence. A severe drought in 2015 (an El Niño year) dramatically increased the significant subsidence area to 659 km2. Both InSAR and leveling detected similarly significant subsidence areas in 2017, showing that InSAR was an effective technique for assessing whether a subsidence mitigation measure worked. The newly opened Hushan Reservoir can supply surface water during dry seasons and droughts to counter rain shortage and can thereby potentially reduce land subsidence caused by groundwater extraction.

scholarly journals Space-Time Evolutions of Land Subsidence in the Choushui River Alluvial Fan (Taiwan) from Multiple-Sensor Observations

2021 ◽  
Vol 13 (12) ◽  
pp. 2281
Author(s):  
Yi-An Chen ◽  
Chung-Pai Chang ◽  
Wei-Chia Hung ◽  
Jiun-Yee Yen ◽  
Chih-Heng Lu ◽  
...  
Keyword(s):  
Land Subsidence ◽  
High Speed ◽  
Economic Loss ◽  
Alluvial Fan ◽  
Detection Mechanism ◽  
High Speed Rail ◽  
Monitoring Wells ◽  
Multiple Sensor ◽  
Small Baseline ◽  
Observation Wells

Land subsidence is a significant problem around the world that can increase the risk of flooding, damage to infrastructure, and economic loss. Hence, the continual monitoring of subsidence is important for early detection, mechanism understanding, countermeasure implementation, and deformation prediction. In this study, we used multiple-sensor observations from the Continuous Global Positioning System (CGPS), the small baseline subset (SBAS) algorithm, interferometric synthetic-aperture radar (InSAR), precise leveling, multi-layer compaction monitoring wells (MLCWs), and groundwater observation wells (GWs) to show the spatial and temporal details of land subsidence in the Choushui River alluvial fan (CRAF), Taiwan, from 1993 to 2019. The results showed that significant land subsidence has occurred along the coastal areas in the CRAF, and most of the inland subsidence areas have also experienced higher subsidence rates (>30 mm/yr). The analysis of subsidence along the Taiwan High Speed Rail (THSR) revealed a newly formed subsidence center between Tuku and Yuanchang Townships in Yunlin, with high subsidence rates ranging from 30 to 70 mm/yr. We propose a map showing, for the first time, the distribution of deep compactions occurring below 300 m depth in the CRAF.

scholarly journals Adjacent-Track InSAR Processing for Large-Scale Land Subsidence Monitoring in the Hebei Plain

2021 ◽  
Vol 13 (4) ◽  
pp. 795
Author(s):  
Xi Li ◽  
Li Yan ◽  
Lijun Lu ◽  
Guoman Huang ◽  
Zheng Zhao ◽  
...  
Keyword(s):  
Time Series ◽  
Synthetic Aperture Radar ◽  
Land Subsidence ◽  
Large Scale ◽  
Synthetic Aperture ◽  
Hebei Plain ◽  
Deformation Velocity ◽  
Large Scale Land ◽  
Subsidence Monitoring ◽  
Aperture Radar

Large-scale land subsidence has threatened the safety of the Hebei Plain in China. For tens of thousands of square kilometers of the Hebei Plain, large-scale subsidence monitoring is still one of the most difficult problems to be solved. In this paper, we employed the small baseline subset (SBAS) and NSBAS technique to monitor the land subsidence in the Hebei Plain (45,000 km2). The 166 Sentinel-1A data of adjacent-track 40 and 142 collected from May 2017 to May 2019 were used to generate the average deformation velocity and deformation time-series. A novel data fusion flow for the generation of land subsidence velocity of adjacent-track is presented and tested, named as the fusion of time-series interferometric synthetic aperture radar (TS-InSAR) results of adjacent-track using synthetic aperture radar amplitude images (FTASA). A cross-comparison analysis between the two tracks results and two TS-InSAR results was carried out. In addition, the deformation results were validated by leveling measurements and benchmarks on bedrock results, reaching a precision 9 mm/year. Twenty-six typical subsidence bowls were identified in Handan, Xingtai, Shijiazhuang, Hengshui, Cangzhou, and Baoding. An average annual subsidence velocity over −79 mm/year was observed in Gaoyang County of Baoding City. Through the cause analysis of the typical subsidence bowls, the results showed that the shallow and deep groundwater funnels, three different land use types over the building construction, industrial area, and dense residential area, and faults had high spatial correlation related to land subsidence bowls.

scholarly journals Multiple sensors applied to monitorland subsidence in Central Taiwan

2015 ◽  
Vol 372 ◽  
pp. 385-391 ◽  
Author(s):  
W.-C. Hung ◽  
C. Wang ◽  
C. Hwang ◽  
Y.-A. Chen ◽  
H.-C. Chiu ◽  
...  
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Alluvial Fan ◽  
Persistent Scatterer Interferometry ◽  
High Speed Rail ◽  
Aquifer System ◽  
Multiple Sensors ◽  
Persistent Scatterer ◽  
Global Positioning ◽  
Central Taiwan

Abstract. During 1992–2013, pumping of groundwater caused large-scale aquifer-system compaction and land subsidence in the Choshui River Alluvial Fan (CRAF) in Taiwan. The subsidence has already endangered the operation of Taiwan High Speed Rail (THSR). In this paper, we introduce the multiple sensors monitoring system to study the extent of subsidence in CRAF and its mechanism, including GPS (Global Positioning System), PSI (Persistent Scatterer Interferometry), leveling and multi-layer compaction monitoring well. These sensors complement each other in spatial and temporal resolutions.

scholarly journals Land subsidence due to groundwater pumping: hazard probability assessment through the combination of Bayesian model and fuzzy set theory

2021 ◽  
Vol 21 (2) ◽  
pp. 823-835
Author(s):  
Huijun Li ◽  
Lin Zhu ◽  
Gaoxuan Guo ◽  
Yan Zhang ◽  
Zhenxue Dai ◽  
...  
Keyword(s):  
Set Theory ◽  
Land Subsidence ◽  
Fuzzy Set ◽  
Groundwater Level ◽  
Fuzzy Set Theory ◽  
Bayesian Model ◽  
Large Scale ◽  
Alluvial Fan ◽  
Prevention Measures ◽  
Hazard Assessments

Abstract. Land subsidence caused by groundwater overpumping threatens the sustainable development in Beijing. Hazard assessments of land subsidence can provide early warning information to improve prevention measures. However, uncertainty and fuzziness are the major issues during hazard assessments of land subsidence. We propose a method that integrates fuzzy set theory and weighted Bayesian model (FWBM) to evaluate the hazard probability of land subsidence measured by Interferometric Synthetic Aperture Radar (InSAR) technology. The model is structured as a directed acyclic graph. The hazard probability distribution of each factor triggering land subsidence is determined using Bayes' theorem. Fuzzification of the factor significance reduces the ambiguity of the relationship between the factors and subsidence. The probability of land subsidence hazard under multiple factors is then calculated with the FWBM. The subsidence time series obtained by InSAR is used to infer the updated posterior probability. The upper and middle parts of the Chaobai River alluvial fan are taken as a case-study site, which locates the first large-scale emergency groundwater resource region in the Beijing plain. The results show that rates of groundwater level decrease more than 1 m yr−1 in the confined and unconfined aquifers, with cumulative thicknesses of the compressible sediments between 160 and 170 m and Quaternary thicknesses between 400 and 500 m, yielding maximum hazard probabilities of 0.65, 0.68, 0.32, and 0.35, respectively. The overall hazard probability of land subsidence in the study area decreased from 51.3 % to 28.3 % between 2003 and 2017 due to lower rates of groundwater level decrease. This study provides useful insights for decision makers to select different approaches for land subsidence prevention.

scholarly journals Characterization of land subsidence induced by groundwater withdrawals in Wenyu River alluvial fan, Beijing, China

2015 ◽  
Vol 372 ◽  
pp. 481-484
Author(s):  
R. Wang ◽  
Y. Luo ◽  
Y. Yang ◽  
F. Tian ◽  
Y. Zhou ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Land Subsidence ◽  
Monitoring Program ◽  
Alluvial Fan ◽  
Plain Area ◽  
Beijing Plain ◽  
Groundwater Overdraft ◽  
Subsidence Monitoring ◽  
Beijing China

Abstract. The Beijing plain area has suffered from severe land subsidence owing to groundwater overdraft. A major example is the Wenyu River alluvial fan in the Beijing plain area. This area has experienced as much as 10 m of land subsidence through 2000s. An integrated subsidence-monitoring program, including borehole extensometer and multilayer monitoring of groundwater, has been designed to meet the needs of monitoring land subsidence in this region. This work has allowed us to characterize land subsidence and understand the mechanical properties of the strata. The analysis results show the development of the land subsidence in this area is consistent with water-level change. The major strata contributing to compression deformation are Mid-Pleistocene stratum which contributed around 70 % of total subsidence. The shallow stratum and deep stratum show elastic mechanical behavior the intermediate stratum exhibit elastic-plastic mechanical behavior.

scholarly journals Spatial–temporal characterization of land subsidence induced by large area distribution of recent dredger fill

2020 ◽  
Vol 382 ◽  
pp. 131-135
Author(s):  
Jinxin Lin ◽  
Hanmei Wang ◽  
Tianliang Yang ◽  
Xinlei Huang
Keyword(s):  
Comparative Analysis ◽  
Land Subsidence ◽  
Large Scale ◽  
Soft Soil ◽  
Soil Layer ◽  
Geological Survey ◽  
Dredger Fill ◽  
Large Scale Land ◽  
And Control ◽  
Level Monitoring

Abstract. Large-scale land subsidence often occurs after large-scale land formation caused by dredger fill, which affects the sustainable development of the region. In order to prevent and control land subsidence in the area with dredger fill, the characteristics of land subsidence and its main influencing factors need to be studied. A typical region was examined using geological survey data, land-level monitoring and comparative analysis, to provide insight regarding the variability of dredger-fill characteristics and impacts on land subsidence. The geological survey results provided the information about burial distribution characteristics of dredger fill and its underlying soil layers. The land-level monitoring results were analyzed to characterize the spatial–temporal distribution of land subsidence. The comparative analysis of land subsidence with the formation time, soil properties, thicknesses of dredger fill and the lower soft soil layer provided information about the different impacts. The monitoring results show that the land subsidence of dredger fill areas was substantially larger than that of adjacent areas. The later the filling was formed, the thicker the filling is, and the more clay-rich the soil property and the thicker the soft soil layer is, the larger the land subsidence is. Finally, the future trend of land subsidence in the study area are given and some suggestions on the prevention and control of land subsidence are also given.

scholarly journals Land Subsidence due to groundwater pumping: Hazard Probability Assessment through the Combination of Bayesian Model and Fuzzy Set Theory

2020 ◽  
Author(s):  
Huijun Li ◽  
Lin Zhu ◽  
Gaoxuan Guo ◽  
Yan Zhang ◽  
Zhenxue Dai ◽  
...  
Keyword(s):  
Set Theory ◽  
Land Subsidence ◽  
Fuzzy Set ◽  
Groundwater Level ◽  
Fuzzy Set Theory ◽  
Bayesian Model ◽  
Large Scale ◽  
Alluvial Fan ◽  
Prevention Measures ◽  
Hazard Assessments

Abstract. Land subsidence caused by groundwater over-pumping threatens the sustainable development in Beijing. Hazard assessments of land subsidence can provide early warning information to improve prevention measures. However, uncertainty and fuzziness are the major issues during hazard assessments of land subsidence. We propose a method that integrates fuzzy set theory and weighted Bayesian model (FWBM) to evaluate the hazard probability of land subsidence measured by Interferometric Synthetic Aperture Radar (InSAR) technology. The model is structured as a directed acyclic graph. The hazard probability distribution of each factor triggering land subsidence is determined using Bayes’ theorem. Fuzzification of the factor significance reduces the ambiguity of the relationship between the factors and subsidence. The probability of land subsidence hazard under multiple factors is then calculated with the FWBM. The subsidence time-series obtained by InSAR is used to infer the updated posterior probability. The upper and middle parts of the Chaobai River alluvial fan is taken as a case-study site, which locates the first large-scale Emergency Groundwater Resource Region in Beijing plain. The results show that rates of groundwater level decrease larger than 1 m/y in the confined and unconfined aquifers, compressible layer thicknesses between 160 and 170 m, and Quaternary thicknesses between 400 and 500 m yield maximum hazard probabilities of 0.65, 0.68, 0.32, and 0.35, respectively. The overall hazard probability of land subsidence in the study area decreased from 51.3 % to 28.3 % between 2003 and 2017 due to lower rates of groundwater level decrease. This study provides useful insights for decision-makers to select different approaches for land subsidence prevention.

Detect groundwater storage in an island watershed by GRACE gravimetry

2020 ◽  
Author(s):  
Chung-Chieh Huang ◽  
Hong-Ru Lin ◽  
Jyun-Lin Chen ◽  
Shao-Yang Huang ◽  
Jet-Chau Wen ◽  
...  
Keyword(s):  
High Precision ◽  
Large Scale ◽  
Field Measurements ◽  
Alluvial Fan ◽  
Small Scale ◽  
Groundwater Storage ◽  
Satellite Gravimetry ◽  
Grace Data ◽  
Terrestrial Water ◽  
Central Taiwan

<p>         Since the successful launch of the Gravity Recovery and Climate Experiment (GRACE) on March 17<sup>th</sup>, 2002, a number of scientists have adopted satellite gravimetry for the detection of variations on terrestrial water storage (TWS). Use of high-precision GRACE gravimetry presents advantages in hydrogeologic studies, such as providing accurate estimates of currents and gravity fields. Many studies have proven that the high-precision GRACE gravimetry can observe large-scale (over 50,000 km<sup>2</sup>) variations in groundwater storage (GWS). However, relatively few studies conducted using satellite gravimetry have focused on scales smaller than 5,000 km<sup>2</sup>.</p><p>        The purpose of this study is to investigate the potential for using GRACE gravimetry to observe small-scale variations in GWS specifically, this paper presents a case study of the Zhoushui River alluvial fan (~2,560 km<sup>2</sup>) in central Taiwan as an example of how well GRACE data compare to field-based data for ascertaining small-scale variations in GWS. Field measurements of groundwater level in 52 observation wells (2002-2017) were used to analyze variations in GWS. Results of this field-based analysis were compared to results obtained using the GWS data (2002-2017) obtained by GRACE gravimetry. This comparison allowed us to evaluate the similarities and differences in both methods as well as to prove the feasibility of using GRACE gravimetry in small-scale regions. Results of our comparative analysis indicate that water resources in small watershed can be successfully managed using gravimetric data collected by GRACE satellite.</p><p> </p><p>Keywords: Groundwater storage, GRACE, Watershed</p>

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