scholarly journals Leaking recharge mechanism in the multi-layer aquifer system of a typical land subsidence area in Beijing

2020 ◽  
Vol 382 ◽  
pp. 309-314
Author(s):  
Kunchao Lei ◽  
Fengshan Ma ◽  
Jiurong Liu ◽  
Yong Luo ◽  
Wenjun Cui ◽  
...  
Keyword(s):  
Land Subsidence ◽  
Bound Water ◽  
Hydraulic Gradient ◽  
Leakage Flow ◽  
Water Release ◽  
Aquifer System ◽  
Aquifer Systems ◽  
Gradient Calculation ◽  
Upper Aquifer ◽  
Shallow Strata

Abstract. It is of great significance to reveal the mechanism of land subsidence to further find out the mechanism of leakage flow in multi-layer aquifer systems and the water-release compression of weak aquifers. In this paper, conditions of groundwater leakage flow are expounded, and the initial hydraulic gradient calculation formula in the aquitards are deduced. The data of Tianzhu Land Subsidence Monitoring Station are selected to preliminarily discuss the leakage flow mechanism of the multi-layer groundwater system and water-release compression of weak aquifers. The results show that, firstly the weak aquifer layers in the shallow strata above 91.32 m in Tianzhu Land Subsidence Station are all in the state of unidirectional drainage consolidation, and the water heads in the upper strata are higher than those in the lower strata. However, the hydraulic gradient between the two adjacent aquifers is smaller than the initial hydraulic gradient in the weak aquifer layer, so no leakage recharge effect is generated. Secondly, the water level of the two adjacent aquifers in the deep formation below 91.32 m shows a continuous downward trend, among which the weak aquifer is drained and consolidated on both sides, and the pore water head in the middle of the weak aquifer is the lowest. Although the strata has a large amount of compression, no leakage recharge phenomenon occurs. Thirdly, in a multi-layer aquifer system, when the head difference between adjacent aquifers is small and there is a thick viscous layer between them, it is difficult for the upper aquifer to overcome the shear strength of the bound water in the weak aquifer below, leaking recharge barely occurs.

scholarly journals Analytical assessment of subsidence due to Aquifer Storage and Recovery (ASR) applications to multi-aquifer systems

2000 ◽  
Vol 21 ◽  
Author(s):  
J. Li
Keyword(s):  
Analytical Solution ◽  
Land Subsidence ◽  
Potential Risk ◽  
Aquifer Storage And Recovery ◽  
One Dimensional ◽  
Aquifer System ◽  
Aquifer Storage ◽  
Aquifer Systems ◽  
The One ◽  
Development And Management

The present paper emphasises concerns of land subsidence or compression of clay confining beds caused by periodic withdrawal and injection of water from or into the adjacent aquifers. An analytical solution for a one-dimensional case based on a sandwich model is found so that analysis of potential risk of aquifer system deformation due to the technology of Aquifer Storage and Recovery (ASR) can be conducted. A governing equation expressed directly in terms of displacement is employed to describe the one-dimensional subsidence. For simplicity, saturated aquifer systems are assumed to behave like poroelastic material. A cyclic loading function with a triangle pattern is assumed at boundaries to simulate effective stress induced by changes in hydraulic head at boundaries. The both compression and swelling of clay due to the periodic and linear loads at the boundaries are considered in this model. The two aquifers (one above the confining bed and the other beneath) can be pumped independently of each other. The results from the analytical solution are applied to estimate and predict potential risk of land subsidence due to ASR activity and to provide a first-estimate type of guideline for city or regional development and management of water resources.

The Distribution of Volatile Organics in a Leachate Plume, Gloucester, Ontario

1987 ◽  
Vol 22 (1) ◽  
pp. 49-64 ◽  
Author(s):  
J.F. Devlin ◽  
W.A. Gorman
Keyword(s):  
Organic Contaminants ◽  
Source Area ◽  
Unconfined Aquifer ◽  
High Concentration ◽  
Organic Contamination ◽  
Aquifer System ◽  
Aquifer Systems ◽  
Volatile Organic ◽  
Volatile Organic Contaminants ◽  
Aquifer Sediments

Abstract The Gloucester Landfill is located near Ottawa, Ontario, on a northeast trending ridge of Quaternary age. The ridge comprises outwash sediments which make up two aquifer systems. A confined system exists next to bedrock, and is overlain by a silty-clayey stratum (the confining layer) which is, in turn, overlain by an unconfined aquifer system. Two independent volatile organic plumes have previously been identified at the landfill: the southeast plume, which has penetrated the confined aquifer system, and the northeast plume which is migrating in the unconfined aquifer. The distribution of volatile organic contaminants at the northeast plume site appears to be a function of two factors: (1) heterogeneities in the aquifer sediments are causing the channeling of contaminants through a narrow path; (2) the low fraction of organic carbon in the unconfined aquifer sediments at the northeast site is resulting in little retardation of the contaminants there, relative to those at the southeast site. Acetate was the only volatile fatty acid detected in the leachate. It was measurable only in areas where the volatile organic contamination was significant. Although methane was detected in the contaminated sediments, suggesting that microbial activity was present, the high concentration of acetate (>1000 ppm) which was detected down-gradient from the source area indicates that any biodegradation which is occurring is proceeding at a very slow rate.

scholarly journals Land Subsidence Estimation for Aquifer Drainage Induced by Underground Mining

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4658
Author(s):  
Artur Guzy ◽  
Wojciech T. Witkowski
Keyword(s):  
Environmental Impact ◽  
Land Subsidence ◽  
Field Data ◽  
Underground Mining ◽  
Small Scale ◽  
Aquifer System ◽  
Maximum Value ◽  
The Impact ◽  
Method Model ◽  
Impact Of Mining

Land subsidence caused by groundwater withdrawal induced by mining is a relatively unknown phenomenon. This is primarily due to the small scale of such movements compared to the land subsidence caused by deposit extraction. Nonetheless, the environmental impact of drainage-related land subsidence remains underestimated. The research was carried out in the “Bogdanka” coal mine in Poland. First, the historical impact of mining on land subsidence and groundwater head changes was investigated. The outcomes of these studies were used to construct the influence method model. With field data, our model was successfully calibrated and validated. Finally, it was used for land subsidence estimation for 2030. As per the findings, the field of mining exploitation has the greatest land subsidence. In 2014, the maximum value of the phenomenon was 0.313 cm. However, this value will reach 0.364 m by 2030. The spatial extent of land subsidence caused by mining-induced drainage extends up to 20 km beyond the mining area’s boundaries. The presented model provided land subsidence patterns without the need for a complex numerical subsidence model. As a result, the method presented can be effectively used for land subsidence regulation plans considering the impact of mining on the aquifer system.

The Migration Behaviour of Transuranium Elements in Gorleben Aquifer Systems: Colloid Generation and Retention Process

1988 ◽  
Vol 127 ◽  
Author(s):  
J. I. Kim ◽  
G. Buckau ◽  
H. Rommel ◽  
B. Sohnius
Keyword(s):  
Migration Process ◽  
Transuranium Elements ◽  
Aquifer System ◽  
Migration Behaviour ◽  
Aquifer Systems ◽  
Migration Study

ABSTRACTThe colloid generation as a part of the migration process of trans-uranic ions has been studied in the Gorlben aquifer system. From the migration study for the Gorleben repository site, typical examples are selected to demonstrate the influence of colloids. The quantification of colloid generation and its influence on the dissolution and geochemical sorption of transuranium elements are discussed.

scholarly journals Characterization of earth fissures in South Jiangsu, China

2015 ◽  
Vol 372 ◽  
pp. 249-253 ◽  
Author(s):  
S. Ye ◽  
Y. Wang ◽  
J. Wu ◽  
P. Teatini ◽  
J. Yu ◽  
...  
Keyword(s):  
Land Subsidence ◽  
Earth Fissure ◽  
Aquifer System ◽  
Groundwater Levels ◽  
Earth Fissures ◽  
The Earth ◽  
Cumulative Length ◽  
Differential Land Subsidence

Abstract. The Suzhou-Wuxi-Changzhou (known as "Su-Xi-Chang") area, located in the southern part of Jiangsu Province, China, experienced serious land subsidence caused by overly exploitation of groundwater. The largest cumulative land subsidence has reached 3 m. With the rapid progress of land subsidence since the late 1980s, more than 20 earth fissures developed in Su-Xi-Chang area, although no pre-existing faults have been detected in the surroundings. The mechanisms of earth fissure generation associated with excessive groundwater pumping are: (i) differential land subsidence, (ii) differences in the thickness of the aquifer system, and (iii) bedrock ridges and cliffs at relatively shallow depths. In this study, the Guangming Village Earth Fissures in Wuxi area are selected as a case study to discuss in details the mechanisms of fissure generation. Aquifer exploitation resulted in a drop of groundwater head at a rate of 5–6 m yr−1 in the 1990s, with a cumulative drawdown of 40 m. The first earth fissure at Guangming Village was observed in 1998. The earth fissures, which developed in a zone characterized by a cumulative land subsidence of approximately 800 mm, are located at the flank of a main subsidence bowl with differential subsidence ranging from 0 to 1600 mm in 2001. The maximum differential subsidence rate amounts to 5 mm yr−1 between the two sides of the fissures. The fissure openings range from 30 to 80 mm, with a cumulative length of 1000 m. Depth of bed rock changes from 60 to 140 m across the earth fissure. The causes of earth fissure generation at Guangming Village includes a decrease in groundwater levels, differences in the thickness of aquifer system, shallow depths of bedrock ridges and cliffs, and subsequent differential land subsidence.

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