Joint geophysical prospecting for groundwater exploration in weathered terrains of South Guangdong, China

AbstractExtensive change in land use, climate, and over-exploitation of groundwater has increased pressure on aquifers, especially in the case of crystalline rocks throughout the world. To support sustainability in groundwater management require proper understating of groundwater dynamics and recharge potential. GIS based studies have gained immense popularity in groundwater exploration in recent years because they are fast and provide recent information on the resource for future growth. Thus, the present study utilized a GIS-based Weighted Overlay Index (WOI) model to identify the potential recharge zones and to gain deep knowledge of groundwater dynamics. The in situ infiltration tests have been carried out, which is the key process in groundwater recharge and is neglected in many cases for WOI. In the WOI, ten thematic layers from the parameters influencing and involved in the recharge process are considered to identify potential recharge zones. The results suggested a significant underestimation of recharge potential without considering site-specific infiltration rates that one needs to be considered. The present WOI model considered in situ infiltration information and classified the entire area into four recharge zones, good, moderate, poor, and very poor. The final integrated map compared with the real-time field data like water level fluctuation and infiltration to analyse occurrence and quantification of recharge. The estimated average groundwater draft is 21.9 mcm, while annual renewable recharge is only 5.7 mcm that causing a continuous fall of the groundwater table. The study is useful in selecting regions with more focussed recharge studies and suggested the need of reducing groundwater demand by changing cropping patterns through a predictive decision support tool.

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Assessment and Modeling of Groundwater Potential Zones by using Geospatial and Decision-making approaches: A case study in Anantapur district, Andhra Pradesh, India

Hydrospatial Analysis ◽

10.21523/gcj3.2021050104 ◽

2021 ◽

Vol 5 (1) ◽

pp. 34-44

Author(s):

B. Pradeep Kumar ◽

K. Raghu Babu ◽

M. Rajasekhar ◽

M. Ramachandra

Keyword(s):

Andhra Pradesh ◽

Primary Source ◽

Drainage Density ◽

Groundwater Potential ◽

Groundwater Exploration ◽

Groundwater Potential Zone ◽

Potential Zone ◽

Groundwater Potential Zones ◽

Thematic Layers ◽

Total Study Area

Freshwater scarcity is a major issue in Rayalaseema region in Andhra Pradesh (India). Groundwater is the primary source of drinking and irrigation water in Anantapur district, Andhra Pradesh, India. Therefore, it is important to identify areas having groundwater potential; however, the current methods of groundwater exploration consume a lot of time and money. Analytic Hierarchy Process (AHP)-based spatial model is used to identify groundwater potential zones in Anantapur using remote sensing and GIS-based decision support system. Thematic layers considered in this study were geology, geomorphology, soils, land use land cover (LULC), lineament density (LD), drainage density (DD), slope, and rainfall. According to Saaty’s AHP, all these themes and individual features were weighted according to their relative importance in groundwater occurrence. Thematic layers were finally combined using ArcGIS to prepare a groundwater potential zone map. The high weighted value area was considered a groundwater prospecting region. Accordingly, the GWPZ map was classified into four categories: very good, good, moderate, and poor. The very good GWPZ area is 77.37 km2 (24.93%) of the total study area. The northeastern and southeastern sections of the study area, as well as some medium patches in the center and western regions, are covered by moderate GWPZs, which cover an area of 53.07 km2 (17.10%). However, the GWP in the study area’s central, southwestern, and northern portions is poor, encompassing an area of approximately 79.31 km2 (25.56%). Finally, RS and GIS techniques are highly effective and useful for identifying GWPZs.

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Land deformation associated with exploitation of groundwater in Changzhou City measured by COSMO-SkyMed and Sentinel-1A SAR data

Open Geosciences ◽

10.1515/geo-2018-0054 ◽

2018 ◽

Vol 10 (1) ◽

pp. 678-687 ◽

Cited By ~ 2

Author(s):

Deliang Chen ◽

Yanyan Lu ◽

Dongzhen Jia

Keyword(s):

Land Subsidence ◽

Yangtze River ◽

Yangtze River Delta ◽

Groundwater Exploration ◽

River Delta ◽

Urban Agglomeration ◽

Land Deformation ◽

Small Baseline ◽

Groundwater Rebound ◽

Sbas Insar

Abstract The Urban Agglomeration in Yangtze River Delta is one of the most important economic and industrial regions in China. The City of Changzhou is one of the most important industrial citys in Yangtze River Delta Urban Agglomeration. Activities here include groundwater exploration. Groundwater overexploitation has contributed to the major land deformation in this city. The severity and magnitude of land deformation over time were investigated in Changzhou City. A Small Baseline Subset Interferometric Synthetic Aperture Radar (SBAS-InSAR) technology, provides a useful tool in measuring urban land deformation. In this study, a time series of COSMO-SkyMed and Sentinel-1A SAR images covering Changzhou City were acquired. SBAS-InSAR imaging technique was used to survey the extent and severity of land deformation associated with the exploitation of groundwater in Changzhou City. Leveling data was used to validate the SBAR-InSAR productions, the error of SBAR-InSAR annual subsidence results was within 2 mm. The results showed that three main land subsidence zones were detected at Xinbei, Tianning and Wujin District. Four subsidence points were selected to analyze the temporal and spatial evolution characteristics of land subsidence. The subsidence rate of P1 to P4 was −2.48 mm/year, −12.78 mm/year, −18.09 mm/year, and −12.69 mm/year respectively. Land subsidence over Changzhou showed a trend of slowing down from 2011 to 2017, especially in Wujin District. SBAR-InSAR derived land deformation that correlates with the water level change in six groundwater stations. Indicated that with groundwater rebound, the land rebound obviously, and the maximum rebound vale reached 9.13 mm.

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Construction of Water Table Contour Map and Geo Hydrological Studies on Krishnagiri Using GIS Techniques

International Journal of Engineering & Technology ◽

10.14419/ijet.v7i3.10.15644 ◽

2018 ◽

Vol 7 (3.10) ◽

pp. 120

Author(s):

T Subramani ◽

S Mathialagan

Keyword(s):

Water Table ◽

Hydraulic Head ◽

Groundwater Exploration ◽

Subsurface Water ◽

Contour Map ◽

Contour Lines ◽

Gis Software ◽

Water Table Contour ◽

Contemporary Technology ◽

Water Level Contour

Geo-hydrology and groundwater exploration manner to pick out and to find the zone of recharge of groundwater in a precise river basin or a catchment .water level contour traces (or waft traces) are much like topographic strains on a map. They fully represent "elevations" in the subsurface. Water table contour lines can be used to inform which manner groundwater will glide in a given region. Plenty of wells are drilled and the hydraulic head is measured in each one. Water desk contours are drawn that be a part of areas of identical head .The ones water table contours lines are also called equipotential strains. Bear in mind: groundwater usually movements from a place of the higher hydraulic head to an area of decrease hydraulic head, and perpendicular to equipotential traces. In our challenge, we put into effect concept of water table contour map and geohydrological studies on Krishnagiri using GIS software program which plays the essential position in contemporary technology.

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