江苏睢宁苏02、03井水位异常变化机理探讨

为判别江苏睢宁苏02、03井静水位2014年7月下旬至2021年出现的同步转折上升异常变化是否为地震前兆异常,本研究通过开展降雨量影响分析、井孔含水层系统应力状态分析、井孔水及周边地表水化学组分的分析以及井孔周边地下水开采情况调查等工作,认为苏02、03井水位异常受应力变化影响的可能性较小,受环境因素干扰的可能性较大。为定性分析环境因素的影响,建立合理多元线性逐步回归模型,对2口井2008—2021年地下水位和降雨量、地下水开采量进行对比分析,全面考虑了影响地下水位动态变化的因素,得出最优回归方程。结果表明,前2年和前1年地下水开采量对地下水位有显著影响,而降雨量及当年地下水开采量对地下水位无显著影响,水位上升变化滞后于地下水开采量减少。     

安徽省河流和湖库型饮用水水源地水质评价

饮用水水源地的保护问题是关系国计民生的重大问题,饮用水水源地的水质问题越来越受到社会的关注.运用单因子标准指数法以及卡尔森指数法对安徽省境内91个县级以上的饮用水水源地的水质状况以及31个湖库型水源地富营养化程度进行了综合评价,并提出相应的防护措施.结果表明,全省91个饮用水水源地中水质达标的有83个,达标率为91.2%,其中,河流型水源地达标率为93.3%,湖库型水源地达标率为87%,地下水型水源地达标率为87%.     

宝坻新台井水位对地下水开采的响应特征及机理探讨

结合对以宝坻新台井为中心、半径约3 km地域范围内的地下水开采井的调查结果、宝坻新台井概况和所在地区的水文地质资料以及对重点影响井——杨家口村生活井的抽水实验,就宝坻新台井水位对周边地下水开采的响应特征进行了研究,结果表明:宝坻新台井对周边地下水开采的响应是邻层抽水效应的结果,井管漏点、含水层组间"通透"很可能也是重要的影响因素;杨家口村生活井开采地下水时宝坻新台井水位分钟值曲线会出现下降型畸变,开采结束后逐渐恢复,响应的滞后时间在1 min之内;杨家口村生活井持续开采地下水7 h实验过程中,宝坻新台井水位分钟值曲线下降型畸变持续存在,未呈现出"平衡状态";宝坻新台井水位对周边地下水开采的响应可能是由于井管存在漏点或井管外存在空隙的原因所致。     

通辽井水位和水温动态变化影响因素分析

结合区域地下水开采、降雨等资料,对通辽井水位、水温的趋势和年变化影响因素进行了分析。同时,利用水位M_2波潮汐因子分析和水温梯度试验及结果等,证实了该井地下水类型为混合水,区域地下水开采和降雨是水位和水温同向变化的主要影响因素。另外,冷水下渗说更能合理地解释该井水位、水温的同步同向变化。     

云南姚安井2009年10月后水位下降的成因分析

地下水动态的异常变化既有可能是地震前兆异常信息,也有可能是某种环境干扰所引起,如降雨和地下水开采等.如何及时识别并排除环境干扰,对于成功判定地震前兆异常至关重要.云南姚安井水位于2009年10月后出现了下降趋势的异常变化,截止2011年底,最大下降幅度达3m.为分析该井水位异常变化的形成原因,依据姚安井水文地质环境特征,建立了相关的数学物理模型,定量分析了降水量和地下水开采量对该井水位的影响.分析结果表明,姚安井2009年后出现的水位大幅下降可能与区域降水量减小导致的地下水开采活动增强有一定的相关性.文中所采取的异常识别与分析方法,对今后地下水动态异常识别及前兆信息判定工作具有一定的借鉴意义.     

云南姚安井2009年10月后水位下降的成因分析

地下水动态的异常变化既有可能是地震前兆异常信息, 也有可能是某种环境干扰所引起, 如降雨和地下水开采等. 如何及时识别并排除环境干扰, 对于成功判定地震前兆异常至关重要. 云南姚安井水位于2009年10月后出现了下降趋势的异常变化, 截止2011年底, 最大下降幅度达3 m. 为分析该井水位异常变化的形成原因, 依据姚安井水文地质环境特征, 建立了相关的数学物理模型, 定量分析了降水量和地下水开采量对该井水位的影响. 分析结果表明, 姚安井2009年后出现的水位大幅下降可能与区域降水量减小导致的地下水开采活动增强有一定的相关性. 文中所采取的异常识别与分析方法, 对今后地下水动态异常识别及前兆信息判定工作具有一定的借鉴意义.      

唐山马家沟矿井水位异常分析

地下水动态受水文因素影响较大,对地震和构造活动具有较灵敏的响应。判别并排除各种水文干扰,确认地下水在地震前的异常变化,对提高地震分析预报能力,具有重要作用。马家沟矿井水位动态观测层与地下水开采层为同一含水层,井水位于2010年出现破年变异常,加速持续上升,截至2015年,最大上升幅度约30 m。依据该井水文地质环境特征,根据唐山市区2001-2015年地下水位、降雨量、地下水开采量实测资料,建立合理多元回归模型和三维地下水流动模型,发现地下水开采量减少应为影响马家沟矿井水位动态的可能因素。文中采取的异常识别与分析方法,可为其他类似井孔的地下水动态异常识别及判定提供一定借鉴。     

复合型前置库系统去除面源主要污染物的研究

以江苏省溧阳市塘马水库水源地水质安全保障工程为背景,针对水库型水源地面源污染存在的主要问题,构建以沉淀区、浅水区、深水区、潜流人工湿地及生物填料组成强化净化区的复合型前置库分区净化系统,研究面源主要污染物去除规律,为工程示范提供技术参数.结果表明,系统滞水时间为1 d时,去除氮、磷、COD_Cr均有良好效果,分别达到了67.2%、68.2%及89.3%,滞水时间为2~3 d时各污染物去除率增加较少并趋于稳定.引入潜流湿地及强化净化区明显提高了SS、氮、磷、有机物的去除效果,特别是提升了对小颗粒(粒径小于15μm)的去除效果,基于上述研究结果,建议工程示范中滞水时间为2~3 d,并适当优化系统分区结构,提高复合型前置库的净化效率及面积利用率.     

夏县疗1井逸出He异常探讨

1997年8月以来,夏县疗1井共出现4次大幅度的逸出He高值异常。本文通过对观测井周围地质构造概况、冷、热水井的分布、地下水开采及补给、周围用水井的抽水试验分析,认为逸出He的高值异常与地下水开采关系不大,而与山西中南部及晋陕豫交界地区中等地震活动有很好的对应关系。     

华北地区地下水开采对地壳应力的影响

近50年来华北地区遭受持续大面积过量开采地下水,已形成区域地下水漏斗、地面沉降、地陷地裂等地质灾害.然而,地下水的抽取减小了地壳的载荷,造成地壳应力场变化,这一点至今尚未被充分认识.为探索华北地区地下水超采对地壳应力场的影响,本文建立了二维有限元模型,定量计算地下水超采引起地壳变形和应力场变化.结果表明:华北地区地下水开采会引起地表抬升达+12.4cm;漏斗区上、中地壳的水平拉应力增量分别达到70kPa和35kPa;而在地下水开采区外围,水平压应力增量达20kPa;而华北地区构造主压应力积累速率约为0.5kPa·a-1.通过对比华北地区1980年前后5级以上地震的分布状况,本文认为地下水开采对区域构造应力场的扰动不可忽略,其卸载过程可能对华北地区大地震孕震过程存在减缓作用.     

The Effect of Latex Gloves and Nylon Cord on Ground Water Sample Quality

Eighteen sites in South Carolina under investigation by the Superfund program were sampled to determine ambient ground water quality. Samples from 11 of 15 monitoring wells sampled with a bailer contained either caprolactam or Santowhite® (a registered trademark of the Monsanto Co.) or both organic compounds. A maximum of 540 μg/L of caprolactam and 780 μg/L of Santowhite was observed in the samples from the monitoring wells. None of the samples collected using dedicated submersible pumps at 28 other wells contained either compound.
Caprolactam is used in the manufacturing of nylon cord, and Santowhite is used as an antioxidant in latex gloves. Therefore, it was suspected that the nylon cord used to raise and lower the bailer and the latex gloves that were worn during sampling may have contributed the caprolactam and Santowhite to the sample.
An experiment using pH-adjusted distilled water and private well water revealed that the nylon cord and the latex gloves may contribute contaminants to ground water samples. Research is needed into the potential for caprolactam and Santowhite to interfere with laboratory analyses in addition to the potential for absorption of contaminants by nylon cord. Until additional information is available, alternative materials or sampling techniques should be considered to minimize the potential impact of nylon cord and latex gloves on the quality of bailed samples.     

Storage and Preservation of Artificial Sweeteners in Groundwater Samples

Compound‐specific standardized sampling and storage methods are not available for artificial sweeteners found in groundwater. This study aimed to understand: (1) the appropriate length of storage time for samples containing acesulfame (ACE), sucralose (SUC), saccharin (SAC), and cyclamate (CYC) in simulated groundwater (SGW); (2) conditions of their stability; and (3) which sampling materials are appropriate for sample collection. The evaluated storage conditions included acidification, headspace, exposure to light, and refrigeration; the evaluated sampling materials included steel, stainless steel, aluminum, polyvinyl chloride, polyamide (nylon), polypropylene (PharMed BPT?) tubing, styrene‐ethylene‐butylene co‐polymer (MasterFlex?) tubing, and polytetrafluoroethylene (Teflon?) tubing. All compounds evaluated were stable in storage at 4 °C for 241 d (8 months). Concentrations of artificial sweeteners were consistently within 60% to 120% of original concentrations, except ACE and SAC that were substantially lower under acidified conditions at 25 °C after 241 d. Artificial sweetener concentrations remained nearly constant while in contact with all sampling materials except steel. SEM and TEM images showed oxidation of steel occurred; moreover, removal of all artificial sweetener compounds from aqueous solution had occurred after 289 d. These results suggest artificial sweetener analyses conducted within 14 d of sample collection produce optimal results; however, longer storage times may be acceptable under certain conditions. The results also suggest concentrations of artificial sweeteners in SGW are not affected by contact with typical well casing, sampling, and storage materials, with the exception of steel. The findings from this study will improve the use of artificial sweeteners as tracers in environmental studies.     

Effect of groundwater interception and irrigation on salinity and piezometric levels of an aquifer

The major strategy used to prevent the discharge of highly saline groundwater to the River Murray in southeastern Australia is groundwater interception and disposal. The basic design principle assumes that the extraction of groundwater from an aquifer hydraulically connected to the river, using a line of pumps positioned close and roughly parallel to the river, will decrease piezometric heads thereby reducing the discharge of saline groundwater to the river. The paper considers one of these schemes which was designed for the Mildura area on the basis of a hydrogeological investigation. It analyses the effects on piezometric head and groundwater salinity due to the groundwater interception scheme and adjacent irrigation activity over a period of several years from January 1980. It is shown that piezometric heads have decreased significantly in the stretch close to the river. A slight reduction in groundwater salinity is also apparent in this stretch except for an area between the river and a holding basin used for disposal of the saline effluents emanating from the groundwater interception scheme. This general reduction in groundwater salinity is mainly caused by pumping from the groundwater interception scheme and recharge from irrigation. The exception in the trend in groundwater salinity is due to the movement of a highly saline body of groundwater from the holding basin towards the River Murray. Results of this Australian experience should be helpful to the designers of similar salinity mitigation schemes elsewhere.     

Assessment of groundwater pollution risk as a characteristic of the stability of its quality

Definitions of hazard and risk of groundwater pollution are given. A deterministic method for the assessment of groundwater pollution risk using estimates of groundwater protection against and vulnerability to pollution and stability indicators of groundwater quality is considered. Also presented are the principal methodological approaches to the assessment of groundwater protection against pollution and the formation of the structure of indicators and indices characterizing the stability of groundwater quality. The structure of hazard, risks, and damages associated with groundwater pollution is shown. Expert appraisal method is used for the assessment of groundwater pollution risks.     

Statistical analyses of the effect of a drainage tunnel on landslide hydrogeological characteristics

A high groundwater level is highly relevant to the slope instability. Drainage tunnel is an effective method for groundwater level control, but its effect on landslide hydrogeological characteristics is rarely discussed. This study analysed the changes of the landslide hydrogeological characteristics under the effect of a drainage tunnel by real-time monitoring of rainfall, groundwater level, and surface displacement. The trend and mutation of groundwater level are analysed by the Mann–Kendall test and the Mann–Kendall mutation test. The memory effect of groundwater in the landslide area was analysed using autocorrelation analysis. The response characteristics of groundwater level to rainfall were evaluated using cross-correlation analysis and mutual information theory. Variations of groundwater levels were further investigated based on hydrograph analysis. Results showed that the groundwater level had a downward trend from 2016 to 2017. The significant downward trend of groundwater levels began in August 2016. The memory effect of groundwater levels was longer under the effect of the drainage tunnel. Before the construction of the drainage tunnel, the response time of groundwater to rainfall was less than 3 hr and rainfall can generate dramatic groundwater level variations. After the drainage tunnel was completed, time lags can be observed in the groundwater response, and the variation of groundwater levels was smaller than before. A strong correlation was found between groundwater levels and the landslide movement. This study demonstrated that the drainage tunnel had effectively controlled the groundwater level in the landslide and ensured the stability of the landslide.     

Groundwater dynamics in a till hillslope: flow directions,gradients and delay

Knowledge of groundwater dynamics is important for the understanding of hydrological controls on chemical processes along the water flow pathways. To increase our knowledge of groundwater dynamics in areas with shallow groundwater, the groundwater dynamics along a hillslope were studied in a boreal catchment in Southern Sweden. The forested hillslope had a 1‐ to 2‐m deep layer of sandy till above bedrock. The groundwater flow direction and slope were calculated under the assumption that the flow followed the slope of the groundwater table, which was computed for different triangles, each defined by three groundwater wells. The flow direction showed considerable variations over time, with a maximum variation of 75°. During periods of high groundwater levels the flow was almost perpendicular to the stream, but as the groundwater level fell, the flow direction became gradually more parallel to the stream, directed in the downstream direction. These findings are of importance for the interpretation of results from hillslope transects, where the flow direction usually is assumed to be invariable and always in the direction of the hillslope. The variations in the groundwater flow direction may also cause an apparent dispersion for groundwater‐based transport. In contrast to findings in several other studies, the groundwater level was most responsive to rainfall and snowmelt in the upper part of the hillslope, while the lower parts of the slope reached their highest groundwater level up to 40 h after the upper parts. This can be explained by the topography with a wetter hollow area in the upper part. Copyright © 2011 John Wiley & Sons, Ltd.     

Temporal variation of stable isotopes in a precipitation–groundwater system: implications for determining the mechanism of groundwater recharge in high mountain–hills of the Loess Plateau,China

The groundwater in shallow loess aquifers in high mountain–hills in the western Loess Plateau in China is almost the sole water resource for local residents. However, the question about how the loess groundwater naturally circulates in these high mountain–hills, characterized by low precipitation and high potential evaporation, remains unclear. The objectives of this study are to evaluate the application of hydrogen and oxygen isotopes to (1) examine temporal variations of the isotopic composition of precipitation and shallow groundwater and (2) uncover the mechanism of groundwater recharge in high mountain–hills. Results from 2 years of monitoring data show a difference in the stable isotopes for groundwater and local precipitation between the winter and summer periods. Similar to precipitation, stable isotopes in groundwater are observed to be depleted in winter and enriched in summer, particularly in oxygen isotope. A prominent characteristic is that H and O isotopes of groundwater show a very clear response to strong precipitation in the rainy season in 2013. The results highlight that local precipitation is the likely recharge source for groundwater in shallow loess aquifers. Annual recharge from local precipitation maintains the groundwater resource in the shallower loess aquifer. The mechanisms governing shallow loess groundwater recharge in high mountain–hills were evaluated. In addition to possible vertical slow percolation of soil water through the unsaturated zone, rapid groundwater recharge mechanisms have been identified as temporal preferential infiltration through sinkholes, slip surface or landslide surface and through the interface of loess layer and palaeo‐soils. Most groundwater can be recharged after a heavy rainy season. Copyright © 2015 John Wiley & Sons, Ltd.     

3种人工载体净化富营养化水体能力的比较

通过野外模拟实验,对比3种不同理化性状人工载体(立体填料、生物绳和尼龙纱网)净化太湖梅梁湾富营养化水体的能力,并探讨影响人工载体水质净化能力的生物与非生物因素.结果表明:(1)所选择的3种人工载体均能显著降低水体的浊度,其中尼龙纱网处理组中水体浊度下降了94.2％,其单位质量载体净化量最高(36.18NTU/g);(2)与对照组相比,各人工载体处理组中,水体中藻类的生长都受到极显著抑制;(3)3种人工载体对水体中TN、TP的去除效果差异极显著,其对TN累积去除率分别为25.55％、10.21％、51.54％,对TP累积去除率分别为38.93％、38.33％、62.98％;(4)载体理化性状、附着藻类与细菌的生物量和活性、挂载量以及载体上溶解态营养盐的释放是影响人工载体水质净化能力的重要因素.综上,尼龙纱网因具备单位质量附着生物的生物量与活性高、自身滞留溶解态营养盐少以及质量轻且价格经济等优势成为净化富营养化水体较为理想的人工载体.     

Groundwater Governance in the United States: Common Priorities and Challenges

Groundwater is a critical component of the water supply for agriculture, urban areas, industry, and ecosystems, but managing it is a challenge because groundwater is difficult to map, quantify, and evaluate. Until recently, study and assessment of governance of this water resource has been largely neglected. A survey was developed to query state agency officials about the extent and scope of groundwater use, groundwater laws and regulations, and groundwater tools and strategies. Survey responses revealed key findings: states' legal frameworks for groundwater differ widely in recognizing the hydrologic connection between surface water and groundwater, the needs of groundwater‐dependent ecosystems, and the protection of groundwater quality; states reported a range in capacity to enforce groundwater responsibilities; and states have also experienced substantial changes in groundwater governance in the past few decades. Overall, groundwater governance across the United States is fragmented. States nevertheless identified three common priorities for groundwater governance: water quality and contamination, conflicts between users, and declining groundwater levels. This survey represents an initial step in a broader, continuing effort to characterize groundwater governance practices in the United States.     

Simulation of the spatio‐temporal extent of groundwater flooding using statistical methods of hydrograph classification and lumped parameter models

This article presents the development of a relatively low cost and rapidly applicable methodology to simulate the spatio‐temporal occurrence of groundwater flooding in chalk catchments. In winter 2000/2001 extreme rainfall resulted in anomalously high groundwater levels and groundwater flooding in many chalk catchments of northern Europe and the southern United Kingdom. Groundwater flooding was extensive and prolonged, occurring in areas where it had not been recently observed and, in places, lasting for 6 months. In many of these catchments, the prediction of groundwater flooding is hindered by the lack of an appropriate tool, such as a distributed groundwater model, or the inability of models to simulate extremes adequately. A set of groundwater hydrographs is simulated using a simple lumped parameter groundwater model. The number of models required is minimized through the classification and grouping of groundwater level time‐series using principal component analysis and cluster analysis. One representative hydrograph is modelled then transposed to other observed hydrographs in the same group by the process of quantile mapping. Time‐variant groundwater level surfaces, generated using the discrete set of modelled hydrographs and river elevation data, are overlain on a digital terrain model to predict the spatial extent of groundwater flooding. The methodology is applied to the Pang and Lambourn catchments in southern England for which monthly groundwater level time‐series exist for 52 observation boreholes covering the period 1975–2004. The results are validated against observed groundwater flood extent data obtained from aerial surveys and field mapping. The method is shown to simulate the spatial and temporal occurrence of flooding during the 2000/2001 flood event accurately. British Geological Survey © NERC 2011. Hydrological Processes © 2011 John Wiley & Sons, Ltd.