北京平原地下水水位监测网优化

文章在北京市地下水水位监测现状基础上,分潜水和承压水对北京平原地下水监测网的监测密度和监测频率进行了优化设计。主要采用编制地下水动态类型图的方法进行了地下水水位监测网的优化,克里金插值法能定量评价依据监测网观测值绘制的地下水水位等高线的精度,因而可以用来评价监测优化结果。并根据时间序列分析和统计检验提供的定量标准优化了地下水水位监测频率。优化后,北京平原共有监测孔400眼,其中利用原有监测孔300眼,新设计监测孔100眼,手工监测频率由原来的每月6次优化为每月1次,专项高频率监测可以由地下水自动监测仪实现。文中还对地下水自动监测仪(DIVER)的监测结果和手工监测结果进行了对比评价,提出了地下水水位监测网的维护、管理措施和信息发布方式。     

关中盆地地下水动态监测网络设计与应用

本文在关中盆地现有监测网的基础上,基于GIS技术,采用建设监测剖面与编制地下水动态类型图相结合的方法,对关中盆地地下水动态监测网进行了优化调整,形成4横5纵共9条监测剖面、239个监测点的地下水动态监测网,其中潜水监测井120个,承压水监测井119个;利用原有监测井165个,新增监测井74个。新建监测网能够较全面地控制关中盆地区域地下水动态变化,在2011年＂严重缺水地区地下水监测项目＂中,以动态监测数据为依据,确定了主要干旱区位置,为政府应急抗旱找水打井提供了技术支撑。     

河套平原浅层地下水动态监测网优化设计

河套平原的地下水动态监测网存在监测井空间布局不合理的问题,限制了地下水研究工作的进一步深入.采用水文地质分析法和克里金插值法,并结合实际情况对河套平原的浅层地下水监测网络进行了优化设计.地下水动态影响因素分区图的编制主要考虑了地貌、包气带岩性、浅水位埋深、含水层渗透系数、年均降水量、年均蒸发量以及地下水开采模数7个因子.结果表明,优化设计的监测网共有监测井428眼,优化后Kriging插值误差标准差为2.53~10.99 m,比优化前(2.75~27.00 m)显著降低,这说明优化设计的监测网精度有很大提高.此外,优化后的监测网不仅能够对河岸带、断裂带、咸淡水交互带、地下水降落漏斗区等关键地段的水位实施监测,还能够满足不同地区对监测井密度的需求,具有一定的参考和实践价值.     

地下水质监测——水文地质系统污染预防的有效方法

地下水质监测在地下水保护和质量守恒方面起着重要作用。在捷克斯洛伐克开展的国家、区域和特殊场地监测项目主要涉及地下水质和区域污染扩散问题相关背景资料的收集。安装有数据自动收集系统的试验监测站，优化了监测方法、监测网的设计和采样技术。捷克斯洛伐克的地下水质监测为密集耕作区相关决策与政策的制定提供了依据。对捷克斯洛伐克多个地区的浅层脆弱性含水层的时空变化进行了评价，从而为土地利用综合规划和地下水保护管理提供依据。     

济南岩溶泉域地下水位监测

文章采用编制济南岩溶泉域地下水动态类型图的方法优化设计了地下水水位监测密度。通过对地下水水位多年变化趋势的分析确定了手测监测频率。选取质量好的观测孔安装了水位自计仪,提出了地下水水位监测维护措施。将对相关政府部门和每个水用户提供所需的地下水信息,以便达到水管理者与水用户共同参与泉水保护的目的。     

国外地下水监测

美国地下水监测网发展较快,地下水与地表水长期监测工作由内政部下属的地质调查所负责。在布置地下水监测点时,利用了航空照片和优化理论。美国(阿拉斯加除外),约有16000个地下水长期监测点,监测区每330km~2一个点。泉流量监测点近一千个。各州的具体情况又有不同。如爱达荷州,由404个地下水监测井和23个泉组成了该州的基本监测网。并以年报的形式出版该州的水资源数据。     

温州市地下水动态监测及进展

温州市地下水动态监测始于上世纪八十年代初,以温瑞平原为监测重点,近年来监测范围逐步扩大至平阳、苍南地区,监测方式由单一的人工监测向自动化监测发展,安装了10台地下水水位水温自动监测仪.但也存在不少问题,监测井布设缺少统一规划,同时破坏严重,许多用于监测的生产井停用,造成了监测数据的不连续性,需要布设专门的地下水监测井.     

区域地下水位监测网优化设计方法

区域地下水位监测提供了定量评价含水层地下水位持续下降及其对环境影响必不可少的信息。历史上的地下水位监测网是为了评价地下水资源或监测水源地降落漏斗而设立的,目前它们已经不能适应为流域水资源综合管理提供必需的信息。本文在综述国际地下水位监测现状的基础上,介绍了区域地下水位监测网优化设计的方法。采用地理信息系统编制的地下水动态类型图为地下水位监测井位置的选择提供了坚实的水文地质基础;克里金插值法能定量评价监测网观测值绘制的地下水位等高线的精度,因而可以用来定量设计地下水位监测网;时间序列分析和统计检验提供了优化地下水位监测频率的定量标准。这些方法已被应用于北京平原、乌鲁木齐河流域和济南岩溶泉域,其成果将在本刊分期发表。     

水环中心自主研制地下水监测装置两项成果获国家实用新型专利

近日,中国地质调查局水文地质环境地质调查中心依托地质调查项目自主研制的地下水动态自动监测仪、地下水动态自动监测气压平衡装置两项成果获国家知识产权局授予的实用新型专利。地下水动态自动监测仪是一种地下水监测的专用设备,是针对全国地下水监测网已经建立,但现场数据采集设备尚未配置的情况下研制的。     

区域地下水环境监测与未来发展的思考

文章指出了我国地下水环境面临的严峻形势,分析了国内地下水监测体系存在的问题。以北京地区为例,回顾了地下水监测的历史和发展过程,介绍了北京地区1:5万精度的立体分层区域监控网和地下水污染源监控网。针对北京在南水进京和京津冀协同发展的新水情条件下,提出了地下水环境监测网未来发展的对策与建议,指出必须要对监测网定期优化(包括点位密度、监测频率、测试组分)、搭建数据共享平台、争取尽快立法,以确保这项工作顺利开展。     

http://www.sciencedirect.com/science/article/pii/S1674987112000400

Monitoring of regional groundwater levels provides important information for quantifying groundwater depletion and assessing impacts on the environment Historically,groundwater level monitoring wells in Beijing Plain,China,were installed for assessing groundwater resources and for monitoring the cone of depression.Monitoring wells are clustered around well fields and urban areas.There is urgent need to upgrade the existing monitoring wells to a regional groundwater level monitoring network to acquire information for integrated water resources management.A new method was proposed for designing a regional groundwater level monitoring network.The method is based on groundwater regime zone mapping.Groundwater regime zone map delineates distinct areas of possible different groundwater level variations and is useful for locating groundwater monitoring wells.This method was applied to Beijing Plain to upgrade a regional groundwater level monitoring network.     

Evaluation of groundwater monitoring network of Kodaganar River basin from Southern India using entropy

A discrete entropy-based approach is used to assess the groundwater monitoring network that exists in Kodaganar River basin of Southern India. Since any monitoring system is essentially an information collection system, its technical design and evaluation require a quantifiable measure of information and this measure can be derived using entropy. The use of information-based measures of groundwater table shows that the existing monitoring network contains a sufficient number of wells but is not well designed for the measurement of groundwater level. Entropy-based results show that 15 wells are vital to measure regional groundwater level, not 28 wells which are being monitored effectively in this basin.     

乌鲁木齐河流域地下水水质监测网设计

文章运用地下水易污性编图及污染源分布图法进行了乌鲁木齐河流域地下水水质监测网设计。共设计了130监测孔,现有46个监测孔,另需要84个新的监测孔。按监测类型分为面源监测点22个,点源监测点87个,重点水源地与泉水监测点21个。按监测运行分长期监测点55个,流域普查监测点75个。普查监测点监测频率为1次/5年,长期监测点监测频率为1次/年。首期有针对性地在污染严重的柴窝堡新化厂排污区、乌鲁木齐河谷老排污区、米泉污灌区、米泉工业污染区、老龙河污染区取了25个污染水样测试分析,结果显示地下水已经受到严重污染。     

Identifying influencing wells for gradient estimation in the confined portion of the Gulf Coast aquifer near Kingsville,TX

Hydraulic gradient is a fundamental aquifer characteristic required to estimate groundwater flow and quantify advective fluxes of pollutants. Graphical and local estimation schemes using potentiometric head information from three or four wells are used to compute hydraulic gradients but suffer from imprecision and subjectivity. The use of linear regression is recommended when hydraulic head data from a groundwater monitoring network consisting of several wells are available. In such cases, statistical influence analysis can be carried out to evaluate how each well within the network impacts the gradient estimate. A suite of five metrics, namely—(1) the hat-values, (2) studentized residuals, (3) Cook’s distance, (4) DFBETAs and (5) Covariance ratio (COVRATIO) are used in this study to identify influential wells within a regional groundwater monitoring network in Kleberg County, TX. The hat-values indicated that the groundwater network was reasonably well balanced and no well exerted an undue influence on the regression. The studentized residuals and Cook’s distance indicated the wells with the highest influence on the regression predictions were those that were close to high groundwater production centers or affected by coastal-aquifer interactions. However, the wells in the proximity of the production centers had the highest impact on the estimated gradient values as ascertained using DFBETAs. The covariance ratio which indicates the sensitivity of a monitoring well on the estimated standard error of regression was noted to be significant at most wells within the network. Therefore, networks seeking to address changes in groundwater gradients due to climate and anthropogenic influences need to be denser than those used to ascertain synoptic gradient estimates alone. The magnitude of the groundwater velocity was greatly underestimated when the influential wells were excluded from the network. The direction of flow was affected to a lesser extent, but a complete gradient reversal was noted when the network consisted of only four peripheral wells. The influence analysis therefore provides a valuable tool to assess the importance of individual wells within a monitoring network and can therefore be useful when existing networks are to be pruned due to fiscal constraints.     

Modeling approaches and strategies for data-scarce aquifers: example of the Dar es Salaam aquifer in Tanzania

Management of groundwater resources can be improved by using groundwater models to perform risk analyses and to improve development strategies, but a lack of extensive basic data often limits the implementation of sophisticated models. Dar es Salaam in Tanzania is an example of a city where increasing groundwater use in a Pleistocene aquifer is causing groundwater-related problems such as saline intrusion along the coastline, lowering of water-table levels, and contamination of pumping wells. The lack of a water-level monitoring network introduces a problem for basic data collection and model calibration and validation. As a replacement, local water-supply wells were used for measuring groundwater depth, and well-top heights were estimated from a regional digital elevation model to recalculate water depths to hydraulic heads. These were used to draw a regional piezometric map. Hydraulic parameters were estimated from short-time pumping tests in the local wells, but variation in hydraulic conductivity was attributed to uncertainty in well characteristics (information often unavailable) and not to aquifer heterogeneity. A MODFLOW model was calibrated with a homogeneous hydraulic conductivity field and a sensitivity analysis between the conductivity and aquifer recharge showed that average annual recharge will likely be in the range 80–100 mm/year.     

Optimal design of a groundwater monitoring network in Daqing,China

In the Daqing region of China there are 34 groundwater well fields with a groundwater withdrawal of 81.9×10⁴ m³/d. Due to over-abstraction of the groundwater resources from the 1960s to present, a cone of depression up to 4,000 km² has formed in the area. To monitor the change in the groundwater environment, it is necessary to design an effective groundwater-monitoring network. The sites for monitoring groundwater level were selected by applying the finite-element method coupled with Kalman filtering to the area in which the groundwater resources have been extensively exploited. The criterion is a threshold value of the standard deviation of estimation error. This threshold value is determined by the tradeoff between maximum information and minimum cost, in which the maximum information is characterized by the standard deviation and the minimum cost is equivalent to the number of observation wells. The groundwater flow model was calibrated by an optimal algorithm coupled the finite-element method with Kalman filtering by using the data from 16 observation wells from 1986 to 1993. A simulation algorithm coupled with the finite-element method with Kalman filtering analyzed the location data obtained from the existing 38 observation wells in the same region. The spatial distribution of standard deviation of estimation error is computed and the locations that have the maximum standard deviation are selected as additional sites for augmenting the existing observational well network at a given threshold value of the standard deviation surface. Based on the proposed method for selecting a groundwater level monitoring network, an optimal monitoring network with 88 observation wells with the measurement frequency of 12 times per year is selected in the Daqing region of China.