共查询到19条相似文献，搜索用时 203 毫秒
1.
地下水污染监测网的设计包括取样点在空间上的采样位置和时间上的取样频率这两方面的确定,其目的是为了准确刻画污染羽在含水层中随时间的变化状况。介绍了一种新的基于Delaunay三角形剖分方法用于地下水污染监测网在空间上的去冗余设计。同时,针对Delaunay方法没有考虑含水层参数变化和不能新增必要监测点的缺陷,提出了改进措施。改进的Delaunay方法可以直接与污染物的运移模型耦合,通过获取的含水层参数能够比较好地检验监测网在空间上的去冗余设计效果。实例研究表明,该方法在保证监测精度的基础上,能够找到最优的空间取样位置点,同时与改进前相比,利用该方法得到的地下水污染监测网能更加客观地反映污染物在含水层中的空间分布特征。 相似文献
2.
介绍一种优化地下水污染监测网的软件--MAROS 总被引：1，自引：0，他引：1
MAROS是首个基于Windows平台利用MicrosoftAccess和MicrosoftExcel开发出来的用于地下水污染监测网优化设计的决策支持系统软件。该软件通过统计分析监测区域有关数据在时空上的相关分析结果,来确定监测网在时间上的取样频率和空间上的分布密度,从而保证以最省的监测费用获得地下水污染物随时间和空间变化的最全面信息。本文简单地介绍了MAROS的设计原理和模块组成,并对该软件的优缺点进行了评述。 相似文献
3.
以东北地区某石油烃污染场地为例,在充分掌握研究区内地质、水文地质条件以及相关污染监测数据的基础上,以最优化监测决策支持系统——MAROS为平台,对研究区内现有地下水污染监测网进行优化设计。在阐述数理统计方法、Delaunay方法以及修正的CES方法原理的基础上。分别对区内单井浓度变化趋势和监测网系统污染物质量的空间矩特征、监测井的冗余性以及单井监测频率的有效性进行了分析:基于MAROS平台优化结果,并结合现有地下水污染监测网中取样点的冗余性、空间分布以及监测频率的有效性的分析,提出了该研究区的地下水污染监测网的优化设计方案并分析了其相关影响因素及不确定性因素的影响。研究结果显示,在现有地下水污染监测网中可以去除5口监测井,并根据每口井中污染物浓度的变化趋势、空间分布及其冗余性调整为一年四次、一年一次、两年一次或不监测,进一步提高区内地下水污染监测网的监测效率、降低监测费用,并对地下水污染防治和修复工作具有重要的指导意义。 相似文献
4.
采用模拟-优化方法建立了一个用于地下水污染监测网设计的多目标优化模型,该模型包括最小化监测费用、污染物质量评估误差、污染羽一阶矩评估误差和二阶矩评估误差等4个目标函数,以充分揭示减少地下水污染监测费用与提高污染监测精度之间的权衡关系.将改进小生境Pareto遗传算法与地下水流模拟程序和污染物运移模拟程序相耦合用于求解地下水污染监测网多目标设计模型.算例研究表明,采用进化算法求解监测网的多目标模型,能真实地反映各个目标函数间的权衡关系,并且不用考虑传统方法中惩罚因子的影响.与单目标优化模型相比,多目标优化模型可在较短的时间内得到优化问题的一系列Pareto权衡解,以利于相应条件下决策者选择最为经济有效的地下水污染监测方案. 相似文献
5.
根据野外调查及取样分析,文章分析了某中小城市生活垃圾场区地下水污染组分特征,建立了研究区污染组分CODcr和Cl-的数学迁移模型,进行了CODcr、Cl-污染因子在地下水中的迁移模拟。模拟结果与实测值基本一致,证明建立的数学模型是合理的,并解释了类似Cl-的较为稳定的污染组分和类似于CODcr的易降解吸附污染组分在该区地下水中的迁移规律。 相似文献
6.
地下水污染早已成为一个全球性的问题,如何有效的监控地下水污染,即时了解水质水环境状况,针对污染情况提出相应的防治建议和意见,并为经济社会的发展提供依据,这都需要我们定期对地下水污染进行监测研究,建立污染监测网,定期对水质进行取样分析,对水质污染情况进行预报预警。本文从以上角度阐述了地下水污染监测的工作过程。 相似文献
7.
大同地区地下水弥散实验研究 总被引：3，自引：0，他引：3
水动力弥散理论主要研究地下水可溶物质在时间、空间上的变化和弥散运移,预测地下水污染的发展趋势。本文通过对大同御河漫滩中细砂取样,模拟野外地下水水质污染的运移,进行了室内二维弥散实验研究,计算弥散系数,为制订有效的地下水污染防治措施提供科学依据。 相似文献
8.
淄博市大武水源地是中国北方罕见的特大型岩溶-裂隙地下水水源地,地下水开采量为52×10~4m~3/d。为了对岩溶地下水进行有效监测,需要建立最优的地下水监测网。文中在对岩溶地下水流系统分析的基础上,建立了地下水流系统确定性-随机性数学模型,运用有限元与卡尔曼滤波耦合的模拟递推算法,对大武水源地地下水监测网进行了优化设计,结果显示:现有地下水位动态监测网难以达到监测目标,最优地下水位监测网由14个监测井,每月监测一次的监测频率组成,比现有地下水位监测网减少了2个监测井。 相似文献
9.
以安徽省向山垃圾填埋场作为研究区,在分析场区水文地质条件的基础上,运用GMS中的MODF-LOW和MT3 D模块建立地下水流概念模型、数值模型及溶质运移数值模型,并根据取样结果确定污染物因子,模拟正常状况和非正常状况下污染物在地下水环境中的污染路径、污染羽迁移状况和污染物对地下水环境可能造成的影响.研究结果表明:评价区... 相似文献
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11.
Detection of contaminant plumes released from landfills: numerical versus analytical solutions 总被引：4，自引：3，他引：1
N. Buket Yenigül André T. Hensbergen Amro M. M. Elfeki F. Michel Dekking 《Environmental Earth Sciences》2011,64(8):2127-2140
Contaminant leaks released from landfills are a threat to groundwater quality. The groundwater monitoring systems installed
in the vicinity of such facilities are vital. In this study the detection probability of a contaminant plume released from
a landfill has been investigated by means of both a simulation and an analytical model for both homogeneous and heterogeneous
aquifer conditions. Since the detection probability is a sensitive quantity, we first compare the two methods for homogeneous
aquifer conditions to assess the errors that are encountered by performing simulations. The analysis shows that the simulation
model yields the detection probabilities of a contaminant plume at a given monitoring well quite well in the homogeneous case.
For heterogeneous aquifers we apply the approximated analytical model based on macro-dispersivities. Here we find that this
model is insufficient in monitoring system design, since the obtained analytical values of the detection probabilities at
a given monitoring well differ significantly from those computed by simulation. 相似文献
12.
A procedure to estimate the probability of intercepting a contaminant groundwater plume for monitoring network design has been developed and demonstrated. The objective of the procedure is to use all available information in a method that accounts for the heterogeneity of the aquifer and the paucity of data. The major components of the procedure are geostatistical conditional simulation and parameter estimation that are used sequentially to generate flow paths from a suspected contaminant source location to a designated monitoring transect. From the flow paths, a histogram is constructed that represents the spatial probability distribution of plume centerlines. With an independent estimate of the plume width, a relationship between the total cost and the probability of detecting a plume can be made. The method uses geostatistical information from hydraulic head measurements and is conditioned by the data and the physics of groundwater flow. This procedure was developed specifically for the design of monitoring systems at sites where very few, if any, hydraulic conductivity data are available. 相似文献
13.
Paul F. Hudak 《Environmental Geology》2008,55(6):1311-1317
This modeling study evaluated the capability of alternative funnel-and-gate structures with three gates for capturing contaminated
groundwater in a hypothetical unconfined aquifer. Simulated interceptor structures were linear and 45 m wide, consisting of
three gates and two funnels (walls). One gate occupied the center and two gates occupied the ends of the interceptor structures.
The structures, positioned perpendicular to regional groundwater flow, traversed the entire thickness of the aquifer. A total
of four structures were evaluated (numbers designate widths of end, center, and end gates, respectively, in meters): 3-3-3,
2-5-2, 1-7-1, and 4-1-4. Particle tracking and zonal water budgets identified shapes of capture zones and discharge patterns
for each interceptor structure. A mass transport model, accounting for advection and hydrodynamic dispersion, tested the capability
of each structure for capturing a contaminant plume. Results suggest that: time-dependent capture zones underestimate the
amount of time to capture a contaminant plume, wide center gates facilitate plume capture, and wide end gates facilitate lateral
containment of contaminants. Of the structures simulated, the 2-5-2 configuration was relatively efficient at processing and
containing the simulated contaminant plume. 相似文献
14.
Review: Simulation-optimization models for the management and monitoring of coastal aquifers 总被引：2，自引：1，他引：1
The literature on the application of simulation-optimization approaches for management and monitoring of coastal aquifers is reviewed. Both sharp- and dispersive-interface modeling approaches have been applied in conjunction with optimization algorithms in the past to develop management solutions for saltwater intrusion. Simulation-optimization models based on sharp-interface approximation are often based on the Ghyben-Herzberg relationship and provide an efficient framework for preliminary designs of saltwater-intrusion management schemes. Models based on dispersive-interface numerical models have wider applicability but are challenged by the computational burden involved when applied in the simulation-optimization framework. The use of surrogate models to substitute the physically based model during optimization has been found to be successful in many cases. Scalability is still a challenge for the surrogate modeling approach as the computational advantage accrued is traded-off with the training time required for the surrogate models as the problem size increases. Few studies have attempted to solve stochastic coastal-aquifer management problems considering model prediction uncertainty. Approaches that have been reported in the wider groundwater management literature need to be extended and adapted to address the challenges posed by the stochastic coastal-aquifer management problem. Similarly, while abundant literature is available on simulation-optimization methods for the optimal design of groundwater monitoring networks, applications targeting coastal aquifer systems are rare. Methods to optimize compliance monitoring strategies for coastal aquifers need to be developed considering the importance of monitoring feedback information in improving the management strategies. 相似文献
15.
Aquifer remediation for a contaminated site is complex, expensive, and long-term. Groundwater modelling is often used as a tool to evaluate remedial alternatives and to design a groundwater remediation system. Groundwater modelling can also be used as a useful process to identify aquifer characteristics and contaminant behaviour that are not realized prior to modelling, to help diagnose what happened and why it happened at contaminant sites. Three real-world modelling cases are presented to demonstrate how groundwater modelling is applied to help understand contamination problems and how valuable the improved understanding is to decision-making and/or to remedial design. 相似文献
16.
P. F. Hudak 《Environmental Geology》1997,31(1-2):21-26
Simplified approaches are often used to model the removal of groundwater contamination. These approaches can yield poor remediation
schemes because they incorrectly portray the effects of multiple pumping wells. In this study, a pumping configuration designed
by graphically overlaying capture zones having an identical, quasi-elliptical shape was evaluated with a numerical mass transport
model. After a 3-year period (within which the hypothetical aquifer was to be remediated) the contaminant mass had been reduced
by 77%. Due to stagnation zones which developed between extraction wells, approximately 15 years of pumping was required to
remediate the aquifer with the overlay configuration. An alternative design, consisting of an extraction well between two
injection wells along the long axis of the plume, removed the contaminant within the 3-year design period.
Received: 23 October 1995 · Accepted: 18 June 1996 相似文献
17.
基于过程模拟的地下水污染预警是基于包气带和饱和带过程模拟的耦合实现的,且融合了涵盖整个地下水系统的四个预警指标。选取浑河冲洪积扇的李官堡水源地为例,基于Hydrus-1D和Visual Modflow分别进行包气带过程模拟和饱和带过程模拟,针对潜层和承压层的复杂程度分别制定了各自的预警临界值;经分析可知,随着时间的推移,地表污染物持续进入到地下水中,污染晕范围不断扩大,地下水中最大浓度值和水源井浓度值也持续增加,且承压含水层的预警级别要高于潜水含水层;同时基于潜层和承压层中污染物最大浓度值与时间分别近似呈线性关系和指数关系可进行长时间尺度的预警;并提出了零级预警区和一级预警区管理措施以监测和预防为主,二级预警区、三级预警区和四级预警区管理措施以控制和监测为主。 相似文献
18.
辽河三角洲处于陆地和海洋的结合部,蕴含丰富的资源,具有十分重要的战略地位。项目通过三年的时间,查明了辽河三角洲地区主要含水层结构:第四系含水层系统(Q)、明化镇组含水层系统(Nm)、馆陶组含水层系统(Ng)。通过设立动态监测网,建立、完善地下水动态监测体系,实现地下水位和水质的实时监测;地下水水位动态:第四系松散岩类孔隙水较为稳定,水位动态变化不大;上新近系明化镇组和馆陶组地下水,受人类活动影响较大,由于多年连续大量开采,地下水位逐年下降,已形成了2个区域性地下水降落漏斗。地下水水质动态:第四系上更新统(Q3)浅层水Cl-、SO42-、Na+及矿化度持续升高,高矿化度水分布面积扩大,水化学类型复杂化,氯化物型和钠型水分布面积增大,向周边扩散;明化镇组和馆陶组地下水,水质优良,变化不大。针对地下水超采,注重水资源合理配置,适当减少新近系地下水资源的开采,充分利用地表水资源的对策。 相似文献
19.
Temporal monitoring of the pesticide 1,2-dibromo-3-chloropropane (DBCP) and nitrate and indicators of mean groundwater age were used to evaluate the transport and fate of agricultural chemicals in groundwater and to predict the long-term effects in the regional aquifer system in the eastern San Joaquin Valley, California. Twenty monitoring wells were installed on a transect along an approximate groundwater flow path. Concentrations of DBCP and nitrate in the wells were compared to concentrations in regional areal monitoring networks. DBCP persists at concentrations above the US Environmental Protection Agency’s maximum contaminant level (MCL) at depths of nearly 40 m below the water table, more than 25 years after it was banned. Nitrate concentrations above the MCL reached depths of more than 20 m below the water table. Because of the intensive pumping and irrigation recharge, vertical flow paths are dominant. High concentrations (above MCLs) in the shallow part of the regional aquifer system will likely move deeper in the system, affecting both domestic and public-supply wells. The large fraction of old water (unaffected by agricultural chemicals) in deep monitoring wells suggests that it could take decades for concentrations to reach MCLs in deep, long-screened public-supply wells, however. 相似文献