Environmental Geological Problems Research Articles

Swelling evolution mechanism for argillaceous slate in a hydrochemical environment

In radioactive waste repositories and tunnel engineering, the near-field groundwater environment is extremely complex, and changes in multiple chemical components are bound to disrupt the long-term stability of soft rock and soil, thus inducing a series of environmental and engineering geological problems. In this study argillaceous slate was selected as the research object and different types of aqueous chemical solutions were prepared. Lateral constraint expansion tests, X-ray diffraction tests, nuclear magnetic resonance tests and scanning electron microscopy tests were then carried out. The expansion characteristics and evolution mechanism of argillaceous slate in a hydrochemical environment are then revealed at the multiscale level, and the internal relationship between the macroscopic expansion of argillaceous slate and the microscopic and mesoscopic structures explored. Finally, based on experimental data and the grey theory, a non-equal step GM(1, N ) grey prediction model was constructed. The results indicated that: (1) the water‒rock physicochemical reactions mainly affect the microstructure evolution of the argillaceous slate expansion process through pore changes, mineral dissolution and ion exchange; (2) there is a certain correlation between the microstructure parameters and the expansion rate, and it was found that pore volume and clay mineral content are the main factors affecting the expansion of soft rocks; and (3) the model verification results show that the non-equal step GM(1, N ) grey prediction model established in this study can effectively predict the expansion trend of soft rocks in different hydrochemical environments. The research findings can provide a reference for the study of the expansion mechanism of soft rocks in complex hydrochemical environments and the disposal of expansion problems. Supplementary material: the Supplementary Figures and Tables are available at https://doi.org/10.6084/m9.figshare.c.7095856

我国露天废弃矿山环境地质问题及其治理

我国露天废弃矿山环境地质问题及其治理

Co-occurrence of arsenic and fluoride in groundwater of Guide basin in China: Genesis, mobility and enrichment mechanism

Endemic arsenic poisoning and fluorosis caused by primary high arsenic (As) and high fluoride (F−) groundwater have become one of the most serious environmental geological problems faced by the international society. High As and high F− groundwater exists in Neogene confined aquifers in Guide basin, with concentrations of 355 μg/L and 5.67 mg/L, respectively, and showing a co-occurrence phenomenon of As and F− in the groundwater. This poses a double threat to the health of tens of thousands of local residents. In this study, based on the systematic collection of groundwater and borehole sediment samples, analysis of hydrochemistry and isotope indexes, combined with laboratory tests, purpose of this study is to reveal the migration rule and co-enrichment mechanism of As and F− in aquifers, and finally establish a hydrogeochemical conceptual model of the enrichment process of As and F−. The main conclusions are as follows: hydrochemical type of unconfined and confined groundwater in Guide basin is Ca–Na–HCO3 and Na–Cl–HCO3 type, respectively. Main minerals in sediments are quartz and plagioclase. Concentrations of As and F− are lower in unconfined groundwater, but higher in confined groundwater, and which show a gradual increasing trend along the groundwater flow path. The mineralization of natural organic matter in confined aquifer causes iron and manganese oxide minerals containing As to dissolve gradually, which leads to the gradual release of As into groundwater. Large amount of HCO3− produced by mineralization of organic matter precipitate with Ca2+ in groundwater, resulting in reduction of Ca2+ content, promoting the dissolution of fluoride-containing minerals such as fluorite (CaF2), and continuously releasing F− into groundwater. Meanwhile, competitive adsorption reactions in confined aquifers causes more As and F− to be released from mineral surface into groundwater, which gradually migrate and accumulate along groundwater flow. Finally, it is established that a conceptual model for the formation of high As and F− groundwater in the confined aquifer of Guide basin. The research results not only help to improve our understanding of the formation and evolution of groundwater with high As and F− with similar geological background, but also provide scientific basis for rational development and utilization of groundwater, and prevention and control of chronic As and F− poisoning in local and similar areas.

Research on Suitability Evaluation of Urban Engineering Construction Based on Entropy Weight Hierarchy-Cloud Model: A Case Study in Xiongan New Area, China

The development of Xiongan New Area in Hebei Province, China, as a significant national choice, has considerable strategic significance for the integrated growth of Beijing, Tianjin, and Hebei. This paper proposes a cloud model for the suitability evaluation of the construction of Xiongan New Area based on entropy weight analysis, taking into account the geological conditions, groundwater environment, environmental geological problems, and other factors of the suitability of image city development. According to the research, the suitability evaluation findings for the project building employing the cloud model are in strong accord with those of the traditional model and have some application potential. The evaluation’s findings indicate that the project construction in Xiongan New Area is acceptable, with suitable and relatively suitable sites making up 81.4% of the total area and excellent circumstances for project development, construction, and usage. This study offers helpful direction for Xiongan New Area’s urban land-space design and serves as a useful point of comparison for studies looking at the viability of other deep Quaternary Plain region engineering buildings.

Research on the inherent mechanism of rock mass deformation of oil shale in-situ mining under the condition of thermal-fluid-solid coupling

With the gradual maturity of in-situ mining technology of oil shale, environmental geological problems such as ground subsidence after mining become increasingly important. The existing researches focus more on the improvement of mining technology, but less on the deformation of oil shale after mining. In this study, various experiments are used to test the pore characteristics and mechanical properties of oil shale with temperature. It is found that parallel bedding macro fractures are formed during oil shale pyrolysis, and the mechanical properties change differently in parallel and vertical bedding directions. The anisotropy of mechanical properties of oil shale is related to the anisotropy of pore structure for the first time to explains the mechanism of deformation. Moreover, the constitutive model of in-situ mining deformation of oil shale is established through statistical damage mechanics combined with pore structure. The deformation of in-situ mining of oil shale under thermal-fluid-solid coupling condition is studied by combining the constitutive model with multi-field coupling numerical simulation. The results show that the compression deformation of oil shale is about 6.5 cm per meter at 200 m underground, and the impact of in-situ mining on geological environment is less than that of traditional mining methods.

Vulnerability assessment of the eco-geo-environment of mining cities in arid and semi-arid areas: A case study from Zhungeer, China

Assessing the ecological and geological environment vulnerability (EGEV) of cities arid and semi-arid regions is important for urban planning, development, and ecological protection. This study investigated the ecological and geological environmental problems and possible potential risk factors in Zhungeer City and constructed an EGEV assessment index system covering the geological environment, human activities, coal mining, and hydrological conditions. We proposed a linear weighted model to calculate the comprehensive weight of each indicator using the Analytical Hierarchy Process (AHP) and Entropy method based on distance function optimization (AELW), and frequency ratio accuracy is then introduced to compare the remarkable classification performance between AELW and other models. The frequency ratio accuracy results show that AELW model has the highest accuracy for EGEV assessment (62.77 %), followed by Multiplicative Integrated Normalization Model (MINM, 61.46 %), AHP (60.98 %), Ideal Point Model (IPM, 60.30 %) and Entropy (53.55 %). The EGEV of Zhungeer was classified as I-V from lowest into highest, among which the EGEV of I-II-III accounted for 78.15 %, EGEV of IV accounted for 16.42 %, and the EGEV of V risk area accounted for 5.43 %, with a good overall ecological and geological environment quality. These results can provide tangible management suggestions for reducing EGEV in Zhungeer city, and the AELW model provides direction for EGEV assessment in other similar areas.

Analysis of Eco-Environmental Geological Problems and Their Driving Forces in the Henan Section of the Yellow River Basin, China

(1) Background: The Henan section of the Yellow River Basin plays an important role in the economic zone of the middle reaches of the Yellow River. However, ecological environmental geological problems such as soil erosion have seriously affected the lives of residents and economic development, resulting in increasingly prominent conflicts between humans and the environment. Therefore, this paper made use of remote sensing images and other reference data, integrated image classification, remote sensing inversion and statistical analysis methods to explore the ecological environmental geological problems and their causes in the Henan section of the Yellow River Basin. (2) Results: the main eco-environmental geological problems in the Sanmenxia–Zhengzhou section are serious soil erosion, degradation of water conservation function and being prone to geological disasters. The main eco-environmental geological problems in the Zhengzhou–Puyang section are poor water and soil conservation function, degradation of water conservation function and poor biodiversity maintenance function. In the last 19 years, the eco-environmental geological problems in the Henan section of the Yellow River Basin have shown a significant improvement trend as a whole. Along the main stream of the Yellow River in Sanmenxia, Luoyang, Jiyuan, Jiaozuo, Zhengzhou and other areas, the eco-environmental geological problems are still prominent; altitude, vegetation and rainfall are the key driving factors of eco-environmental geological problems in the Sanmenxia–Zhengzhou section and rainfall, vegetation and land-use type are the key driving factors in the Zhengzhou–Puyang section. (3) Conclusions: This study comprehensively considered the three aspects of ecology, environment and geology in a total of five research topics. The temporal and spatial distribution characteristics and driving factors of ecological environmental geological problems in the Yellow River Basin were analyzed, which could provide technical support for ecological environmental protection and high-quality development in the Yellow River Basin.

State of Brownfields in the Northern Bohemia, Saxony and Lower Silesian Regions and Prospects for Regeneration by Utilization of the Phytotechnology with the Second Generation Crops

The need to achieve the sustainability goals and to reduce the continuous exploitation of the limited urban areas increases requests for the regeneration of brownfields. The current study aims to review the state of brownfields in the Northern Czech Region and neighboring German (Saxony) and Polish (Silesian) Regions which share a common geological background and environmental problems. The peculiarities of the brownfield’s properties related to the term, classification, legislative framework, access to available data, degree of contamination, and remediation methods were the focus of this review. It was established that the state with brownfield identification and transformation is better in the Czech Republic, followed by Germany, with lower awareness in Poland. The relevant examples of successful brownfield revitalization and the importance of educational components were introduced. A prospective application of the phytotechnology with the second-generation crops for the remediation of brownfields was discussed. The utilization of Miscanthus spp. for marginal lands with low contamination can provide an economic return by having biomass converted into energy or bioproducts and the utilization of the accompanied waste as carbon-rich biochar which can indeed support phytoremediation, enhance plants’ growth and serve as a medium for carbon sequestration. The next steps in the research have to concentrate on comparison of the rehabilitation methods introduced for the targeted regions with the global approach in brownfield redevelopment along with the practical ensuring the phytotechnology potential at the selected brownfields.

黄土高原神府资源开采区生态环境质量时空格局特征

PDF HTML阅读 XML下载 导出引用 引用提醒 黄土高原神府资源开采区生态环境质量时空格局特征 DOI: 10.5846/stxb202204100935 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（31670549，31170664）；自然资源部退化及未利用土地整治工程重点实验室开放基金（SXDJ2019\\03）；中央高校基本科研项目（300102270206） Temporal and spatial pattern characteristics of ecological environmental quality in Shenfu mining area of Loess Plateau Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:煤炭的开采促进了地区经济发展，同时也影响了当地的生态环境。因资源开采区在监测研究中常忽视了生态环境质量的长时间影响和时空变化。以神府开采区为例，基于Landsat系列遥感数据，使用遥感生态指数、Mann-Kendall检验法、R/S分析法等，对该区2000-2020年间生态环境质量时空格局特征进行时间序列分析和空间格局特征研究。结果表明：研究区域20年的RSEI均值为0.469，生态环境质量多年平均属于中等等级。2000-2020年间神府矿区生态环境质量总体上看有所改善，20年前后波动变化维持在0.523；同时建设用地也不断增加，从107.09km2增加至273.53km2。变化趋势上生态环境质量趋势变优、不显著和变差的面积比例分别约为56.1%、16.3%和27.6%。研究区生态环境可持续性整体上不强，大量区域显示反持续性特征。资源开采活动引发的地质环境问题致使生态环境退化，表现为直接影响区生态环境质量低于间接影响区，平均低2.68%。研究揭示了矿区长时间序列的变化状况与未来变化趋势及可持续性特征，探讨工矿业对生态环境质量的影响，为神府矿区生态环境评价与管理提供科学合理的依据。 Abstract:Coal mining not only promotes regional economic development, but also affects the local ecological environment. The long-term influence and spatiotemporal variation of ecological environment quality were often ignored in the previous research about resource mining area. Based on Landsat remote sensing data, remote sensing ecological index, Mann-Kendall test and R/S analysis were used to analyze the temporal and spatial pattern characteristics of ecological environment quality in Shenfu mining area from 2000 to 2020. The results show that the average value Remote Sensing Ecological Index of in the study area was 0.469 in the past 20 years. Besides, the average ecological environment quality of whole study area was in the medium grade. From 2000 to 2020, the ecological environment quality of Shenfu mining area has been improved, and the fluctuation of the eco-environmental quality has remained at 0.523 during two decades. Meanwhile, area of construction land increased from 107.09 km2 to 273.53 km2. The proportion of the area where the trend of ecological quality became better, insignificant and worse were about 56.1%, 16.3% and 27.6%, respectively. Overall the future persistence of ecological and environmental is low, and numerous areas showed anti-persistence characteristics. The geological environment problems caused by the resource exploitation activities led to ecological environment degradation, which showed that the value of RSEI in the directly affected area is about 2.68% lower than that in the indirectly affected area. The study revealed the long-term change status, future change trend and sustainable characteristics in Shenfu mining area. Besides, based on the discussion about impact of industry and mining on the ecological environment quality, it can provide a scientific and reasonable basis for the ecological environment evaluation and management of Shenfu mining area. 参考文献 相似文献 引证文献

Causes, Risk Analysis, and Countermeasures of Urban Road Collapse in China from 2019 to 2020

Urban road collapse seriously threatens people’s lives and property. In recent years, with the accelerating pace of urbanization in China, the number of road collapse accidents (RCAs) has been increasing. Based on 334 RCAs in China’s inland cities from 2019 to 2020, this paper divided the severity of urban road collapse into five grades and analyzed the causes, risks, and countermeasures of urban road collapse. The results indicated that causes of RCAs include rainfall, underground pipe problems, construction in progress, geological environment, road aging, road overload, and unqualified backfilling. Rainfall and underground pipe problems cause 75% of RCAs, and the risk of RCAs caused by underground pipe problems is the greatest. Its calculated value is 6.13, which is 3.2 times that of construction in progress and 22 times that of unqualified backfilling. Construction in progress and geological environment problems are more likely to lead to RCAs with higher severity. Underground pipe problems, rainfall, construction in progress, and geological environmental problems are all more likely to cause RCAs in summer, resulting in 45.9% of RCAs occurring in summer. The risk of RCAs in June is the highest, and its calculated value is 1.5 times that in September and 25 times that in February. According to the calculated values and geographical location factors, China was divided into five regions. Finally, the countermeasures before and after road collapse were introduced.

An advanced hydraulic fracturing technique: Pressure propagation and attenuation mechanism of step rectangular pulse hydraulic fracturing

AbstractHydraulic fracturing technology has played a pivotal role as a key technology in shale gas development, but the geological environmental problems caused have been worrying the public. This paper proposes an advanced step rectangular pulse hydraulic fracturing technique, which can achieve higher pressure and more complex fractures by pumping lower energy fluid. The results indicate that the pressure propagation of step rectangular pulse hydraulic fracturing can be divided into stable and unstable propagation stages. Compared with conventional hydraulic fracturing, longer unsteady propagation time, higher pressure and more complex pressure distribution can be obtained. Step pulse parameters are discussed. We found that the pulse pressure increases linearly with the increase in pulse amplitude. There are optimal pulse frequencies and comprehensive damping coefficients to get optimal fluid pressure in different shale reservoirs. These research results will help reduce geological environmental hazards, and can also provide guidance for the optimization of step rectangular pulse hydraulic fracturing technology in shale reservoirs.

Environmental Geological Problems in Southwest China: A Case Study from the Researches of Regional Landslide Hazards

Humans have paid a lot of attention to environmental geological challenges in recent years. Landslides, being one of the most prevalent geological disasters, are characterized by their suddenness and destructiveness. Southwest China is prone to landslides and debris flows due to its unique geological structure. This paper uses landslides in southwest China as an example, focusing on research on landslide initiation mechanisms and outlining modern landslide monitoring devices and prediction models. Landslides are caused by external variables such as persistent precipitation, groundwater movement, and significant seismic activity, as well as interior reasons such as fine particle rearrangement and the action of positive pore water. The reduction of the friction coefficient of the shear surface, which is induced by the increase of the shear rate, the supercritical carbon dioxide and superheated steam of the shear zone, and the mineral recrystallization process on the shear surface, all have an important impact on reducing the friction coefficient of the shear surface, is a key factor in the occurrence of high-speed remote landslides. Real-time landslide monitoring using space-air-ground and acoustic emission technology, as well as the creation of machine learning-based forecast models, have aided in the research of landslide development and early warning.

A novel calculation method of subsidence waterlogging spatial information based on remote sensing techniques and surface subsidence prediction

Coal mining with high groundwater level causes a series of environmental geological problems, especially surface subsidence and subsidence waterlogging, that destroys a significant amount of cultivated land, damages the ecological environment and influences the sustainable development of coal resource-based cities seriously. However, it is expensive to obtain the spatial information of the subsidence waterlogging by performing the field measurement with sonar and difficult to obtain that by using the empirical formula. There is no dataset for the spatial distribution of subsidence waterlogging to in the assist decision-making on ecological environment governance. Obtaining the spatial information of subsidence waterlogging accurately, especially the past spatial information, is still a challenge. Thus, a novel method for calculating the past spatial information of subsidence waterlogging based on remote sensing technology and surface subsidence prediction method is proposed, and the water boundary discrete-elevation interpolation fusion method (BDIF) is applied to this method, which combines two-dimensional water boundary information extracted by the remote sensing method and the three-dimensional subsidence information predicted by probability integral method to obtain the spatial information of the subsidence waterlogging. The spatial information includes water depth, underwater bottom topography, water surface elevation, subsidence waterlogging area, and subsidence water volume. The subsidence waterlogging in Wugou coal mine was the study area and the spatial information is calculated by the proposed method. Compared with the field measured data in the same period, results show that the average absolute error of water depth is 0.091 m with an average relative error of 7.82%. Waterlogging area is 464,439 m2, and the relative error is 5.84%. The waterlogging volume and error are 529,078 m3 and 4.67%, respectively. Compared with the traditional method, the average accuracies of water depth at the measured points, the waterlogging area, and the waterlogging volume in the calculation results of the new method are increased by 25.81%, 16.81%, and 35%, respectively. Therefore, calculating the spatial information data of the subsidence waterlogging by using the proposed method is convenient and accurate, and this method meets the requirements of engineering precision. Moreover, the spatial information of the subsidence waterlogging from 2018 to 2019 in Wugou coal mine is calculated and the dynamic change characteristics of the subsidence waterlogging are analyzed. This method contributes significantly to provide the accurate spatial information of the subsidence waterlogging for waterlogging disaster prediction, ecological environment treatment, and restoration in coal resource-based cities with high groundwater level.

Construction of evaluation system and evaluation model of urban environmental engineering geological problems —— a case study of Jinan City

In order to further study the problems of urban engineering geological environment, taking Jinan as an example, the environmental engineering geological problems are divided into four aspects: primary environmental engineering geological problems, secondary environmental engineering geological problems, the influence of human activities and the restriction of spring water on engineering construction. A multi-level, multi-objective and multi factor evaluation index system suitable for environmental engineering geology is established. The mathematical model is established by using analytic hierarchy process and fuzzy comprehensive evaluation method to evaluate the primary environmental engineering geological problems, secondary environmental engineering geological problems, the impact of human activities and the restrictive effect of spring water on engineering construction. The mathematical model is established by using Nemero index method to comprehensively evaluate the environmental engineering geological problems in Jinan, and the suitability zoning of engineering construction is carried out.

Key problems on hydro-engineering-environmental geology along the Sichuan-Tibet Railway corridor: Current status and development direction

The Sichuan-Tibet Railway is a century project under construction. The complex geological evolution history has led to large differences in geo-environmental conditions along the railway. Hydrogeological, engineering geological, and environmental geological problems are complex and changeable, which deserves great attention in engineering construction and future operations. Based on a brief review of the past geological work on the Sichuan-Tibet Railway corridor, the hydro-engineering-environmental geological problems that may be faced during the railway construction have been described. The hydrogeological problems include 1) high-pressure water inrush from plateau tectonic karst, 2) high-pressure water inrush and mud outburst from faulted bedrock fissures, 3) high-temperature hot water thermal damage. The engineering geological problems include 1) active faults and strong earthquake disasters, 2) high in-situ stress and rock burst or large deformation in deep tunnel, 3) problem rocks or soils and their disaster effects, 4) high-position landslide disaster chain. The environmental geological problems include 1) acidic water corrosiveness from coal-bearing strata and hydrothermal deposits, 2) wetland ecological degradation, 3) interaction effects between the railway construction and the sensitive ecological environment. In the meanwhile, key scientific and technological issues, which should be deeply studied in the future, are put forward. In terms of hydrogeology, such as 1) sequence law of plateau karst development and types of tectonic karst water storage structures, 2) disaster-generating models and prediction methods of water and mud bursts in deep-buried tunnels, 3) active fault control mechanisms and geothermal water circulation models, 4) identification of high-temperature heat hazard risk and geothermal resources utilization technology. In terms of engineering geology and geohazard, such as 1) investigation of fine features of active faults and related engineering fault effects, 2) development features of deep tectonic stress fields in complex geological structures, 3) engineering geological properties of tectonic melange belts and related disaster effects, 4) surrounding rock stability and disaster effects of deep-buried tunnel under water-mechanical-thermal multi-field coupling condition, 5) mechanisms of high-position run-out landslide and risk control technology under internal and external dynamic coupling. In terms of environmental geology, such as 1) mechanisms of plateau multi-source water conversion cycle and the technology of ecological water demand control in the ecologically fragile area, 2) hydro-ecological environmental effect of tunnel construction, 3) key technology of ecological geological environment monitoring, evaluation and protection, 4) geo-ecological environmental effect of global climate warming, etc. From the view of combining non-profit geological surveys and commercial engineering surveys, a response strategy has been proposed that geological surveys are the foundation, scientific and technological research is the key, and the monitoring of potential hazards and engineering control should be promoted, which provides suggestions on developing direction for hydro-engineering-environmental geology work on major project planning areas.

A Spatial-Scale Evaluation of Soil Consolidation Concerning Land Subsidence and Integrated Mechanism Analysis at Macro-, and Micro-Scale: A Case Study in Chongming East Shoal Reclamation Area, Shanghai, China

Land reclamation has been increasingly employed in many coastal cities to resolve issues associated with land scarcity and natural hazards. Especially, land subsidence is a non-negligible environmental geological problem in reclamation areas, which is essentially caused by soil consolidation. However, spatial-scale evaluation on the average degree of consolidation (ADC) of soil layers and the effects of soil consolidation on land subsidence have rarely been reported. This study aims to carry out the integrated analysis on soil consolidation and subsidence mechanism in Chongming East Shoal (CES) reclamation area, Shanghai, at spatial-, macro-, and micro-scale so that appropriate guides can be provided to resist the potential environmental hazards. The interferometric synthetic aperture radar (InSAR) technique was utilized to retrieve the settlement curves of the selected onshore (Ra) and offshore (Rb) areas. Then, the hyperbolic (HP) model and three-point modified exponential (TME) model were combined applied to predict the ultimate settlement and to determine the range of ADC rather than a single pattern. With two boreholes Ba and Bb set within Ra and Rb, conventional tests, MIP test, and SEM test were conducted on the collected undisturbed soil to clarify the geological features of exposed soil layers and the micro-scale pore and structure characteristics of representative compression layer. The preliminary results showed that the ADC in Rb (93.1–94.1%) was considerably higher than that in Ra (60.8–78.7%); the clay layer was distinguished as the representative compression layer; on micro-scale, the poor permeability conditions contributed to the low consolidation efficiency and slight subsidence in Rb, although there was more compression space. During urbanization, the offshore area may suffer from potential subsidence when it is subjected to an increasing ground load, which requires special attention.

Evaluation of Groundwater Resources and Exploitation Potential: A Case from Weifang City of Shandong Province in China

With the rapid growth of population and economy, the demand for groundwater resources is also increasing, leading to the exploitation of groundwater in some areas far greater than the recharge, which easily causes a series of environmental geological problems such as groundwater drawdown, water quality deterioration, surface subsidence, and so on. Taking Shouguang water resource in Weifang City, Shandong Province, China, as an example, the water-bearing formation in the study area can be divided into three types: pore water-bearing formation of unconsolidated sediments, karst fissure water-bearing formation of carbonate rock, and bedrock fissure water-bearing formation. According to the pumping test results, the groundwater-richness zones in the study area were delineated first. On this basis, by analyzing the dynamic changes of groundwater, the study area was divided into 40 blocks, and the natural recharge of groundwater in each block was calculated by the analogy method of the infiltration coefficient of precipitation. Then, combined with the actual situation of the study area, the allowable withdrawal of groundwater resources, mainly including pore water-bearing formation of unconsolidated sediments, karst fissure water-bearing formation of carbonate rock, and bedrock fissure water-bearing formation, was calculated using the safe yield modulus method, the improved method of the uniform arrangement of wells, and temporary storage capacity, respectively. Through the calculation, it can be concluded that the total allowable withdrawal of shallow groundwater resources in Shouguang city is 6292.5783 × 104 m3/a, that of middle and deep layer groundwater resources is 2574.92 × 104 m3/a, that of karst fissure water in carbonate rock is 1767.92 × 104 m3/a, and that of bedrock fissure water is 307.89 × 104 m3/a. The results show that within the study area, karst fissure water in carbonate rock and bedrock fissure water have immense exploitation potential.

Identifying Potential Sites for Artificial Recharge in the Plain Area of the Daqing River Catchment Using GIS-Based Multi-Criteria Analysis

As an essential component for the development of the Xiong’an New Area, China’s second capital, groundwater in the area has been overexploited, resulting in ecological and environmental geological problems. Therefore, artificial groundwater replenishment measures are urgently required, for which the evaluation of the recharge potential is an important prerequisite. In this study, a GIS (Geographic Information System)-based multi-criteria evaluation system was constructed, considering the source water conditions, recharge infiltration conditions, aquifer storage conditions, and environmental conditions. In addition, factors such as the distance to a canal, source water quality, slope, vadose zone infiltration rate, drainage density, groundwater depth, aquifer hydraulic conductivity, aquifer thickness, groundwater quality, soil quality, and distance to sensitive areas were also analyzed. GIS was used to draw and calculate potential artificial recharge sites. The results showed that the potential recharge sites in the study area are mainly distributed in the alluvial plains on both sides of the river, with a total area of 2103.9 km2, accounting for 15.8% of the total study area. In the Xiong’an New Area, the potential sites are mainly distributed in the alluvial–proluvial plains on both sides of the Baigou River in the north-central area, with a total area of 39.4 km2, accounting for approximately 2.2% of the total area of the Xiong’an New Area.

Study on evolution of groundwater-lake system in typical prairie open-pit coal mine area.

Due to the drought climate and a large amount of groundwater drainage, there are widespread environmental geological problems in prairie open-pit coal mining areas, such as hydrological cycle imbalance, soil desertification and prairie degradation. This study takes the Hulunbeir Prairie Yimin Open-pit Coal Mine as the research object. Basing on the investigation of the groundwater-lake system in the mining area, data of hydrological, meteorological and remote sensing image, the mathematical model of groundwater level-lake area response mechanism in the mining area was constructed by using the principle of water balance. And the influence of mining area development on the lake area of Yimin basin had been predicted and analyzed. The results show that in the past 35years of coal mining, the number of lake groups in Yimin basin has changed from 5 before mining (1982) to 2 (2018), and the total area of lakes has reduced from 6.94km2 before mining to 1.43km2 with an area reduction rate of 79%. The prairie lake-groundwater coupling model was constructed based on the principle of water balance, and the goodness-of-fit reached more than 0.83 after testing. Based on the model, it's predicted that when the Yimin Coal Mine is closed (2045), the area of Chaidaminol lake will shrink to 1.37km2 under the condition of little fluctuation of climatic factors and stable mine development.

Laws and Mechanism of the Fe (III) Clogging of Porous Media in Managed Aquifer Recharge

The use of stormwater for managed aquifer recharge (MAR) has become one of the most important ways to deal with water shortages and the corresponding environmental geological problems, especially in the north of China. The Fe (III) clogging of porous media is a common and significant problem that influences the effect of the infiltration rate. This paper focuses on the migration characteristics and clogging mechanisms of iron hydroxides in sand columns. The results indicate that the permeability of porous media significantly decreased at the inlet of the fine sand column and inside the coarse sand column. We demonstrated that, when the Fe (III) concentration was higher, a smaller infiltration medium size was produced more rapidly, and there was more significant clogging. More than 80% of the injected Fe (III) remained in the sand column, and more than 50% was retained within 1 cm of the column inlet. The mass retention increased with the decrease in the size of the infiltration medium particles and with the increase in the injected Fe (III) concentration. The main material that caused Fe (III) clogging was iron hydroxide colloids, which were in the form of a granular or flocculent membrane coating the quartz sand. The mechanisms of clogging and retention were blocking filtration and deep bed filtration, adsorption, and deposition, which were strongly affected by the coagulation of Fe (III) colloidal particles.