【研究】Groundwater | Volume 58, Issue 2
Guest Editorial/客座社论
What Does the Demise of the National Research Program Mean for Subsurface Water Science?
国家研究计划的终止对地下水科学意味着什么？
Research Papers/研究文章
Revisiting “An Exercise in Groundwater Model Calibration and Prediction” After 30 Years: Insights and New Directions
30年后回顾“地下水模型校正与预测练习”:见解与新方向
In 1988, an important publication moved model calibration and forecasting beyond case studies and theoretical analysis. It reported on a somewhat idyllic graduate student modeling exercise where many of the system properties were known; the primary forecasts of interest were heads in pumping wells after a river was modified. The model was calibrated using manual trial‐and‐error approaches where a model's forecast quality was not related to how well it was calibrated. Here, we investigate whether tools widely available today obviate the shortcomings identified 30 years ago. A reconstructed version of the 1988 true model was tested using increasing parameter estimation sophistication. The parameter estimation demonstrated the inverse problem was non‐unique because only head data were available for calibration. When a flux observation was included, current parameter estimation approaches were able to overcome all calibration and forecast issues noted in 1988. The best forecasts were obtained from a highly parameterized model that used pilot points for hydraulic conductivity and was constrained with soft knowledge. Like the 1988 results, however, the best calibrated model did not produce the best forecasts due to parameter overfitting. Finally, a computationally frugal linear uncertainty analysis demonstrated that the single‐zone model was oversimplified, with only half of the forecasts falling within the calculated uncertainty bounds. Uncertainties from the highly parameterized models had all six forecasts within the calculated uncertainty. The current results outperformed those of the 1988 effort, demonstrating the value of quantitative parameter estimation and uncertainty analysis methods.
Containment of Sources of Groundwater Contamination: Analysis of Mass Fluxes
地下水污染源的控制:质量通量分析
Cutoff walls and liners are used frequently as barriers to isolate contaminants at both controlled and uncontrolled hazardous waste sites. Neville and Andrews (2006) presented a containment criterion for contaminant isolation by a barrier. The analysis of Neville and Andrews (2006) yields the inward Darcy flux that balances the diffusive mass flux from the source so that the net mass flux is zero. A requirement of zero net mass flux may not be achievable in all situations. The analysis developed by Neville and Andrews (2006) is extended to develop straightforward expressions for the long‐term mass fluxes across a barrier for any conditions. In cases where it may not be possible to satisfy a criterion of zero net mass flux, the results from an exact solution for transient solute transport are used to show how the mass fluxes evolve to their long‐term values.
在受控和非受控的危险废物场所，隔断墙和衬里经常被用作隔离污染物的屏障。内维尔和安德鲁斯(2006)提出了一个用屏障隔离污染物的遏制标准。内维尔和安德鲁斯(2006)的分析得出了向内的达西通量，该通量平衡了来自源的扩散质量通量，使得净质量通量为零。并非在所有情况下都可以达到零净质量通量的要求。由内维尔和安德鲁斯(2006)发展的分析被扩展到任何条件下跨越屏障的长期质量通量的直接表达式。在可能无法满足零净质量通量标准的情况下，瞬态溶质运移的精确解的结果用于显示质量通量如何演变为其长期值。
Pathline Density Distributions in a Null‐Space Monte Carlo Approach to Assess Groundwater Pathways
评估地下水路径的零空间蒙特卡罗方法中的路径密度分布
A null‐space Monte‐Carlo (NSMC) approach was applied to account for uncertainty in the calibration of the hydraulic conductivity (K) field for a three‐dimensional groundwater flow model of a major water supply system in Switzerland. The approach generates different parameter realizations of the K field using the pilot point methodology. Subsequently, particle tracking (PT) was applied to each calibrated model, and the resulting particles are interpreted as the spatial pathline density distribution of multiple sources. The adopted approach offers advantages over classical PT which does not provide a means for treating uncertainty originating from the incomplete description of subsurface heterogeneity. Uncertainty in the K field is shown to strongly influence the spatial pathline distribution. Pathline spreading is particularly evident in locations where the information content of the head observations does not sufficiently constrain the estimated parameters. Despite the predictive uncertainty, the pumped drinking water at the study site is most likely dominated by artificially‐infiltrated groundwater originating from the local infiltration canals. The model suggests that within the well field, the central pumping wells could be extracting regional groundwater, although the probability is relatively low. Nevertheless, a rigorous uncertainty assessment is still required since only a few realizations resulted in flow paths that support the field observations. Model results should therefore not be based on only one model realization; rather, an uncertainty analysis should be carried out to provide a sufficiently large suite of equally probable simulations that include all potential sources and pathways.
应用零空间蒙特卡罗(NSMC)方法来解决瑞士主要供水系统的三维地下水流模型的水力传导系数(K)场校准的不确定性。该方法使用引导点方法生成不同的K场参数实现。随后，粒子跟踪(PT)被应用于每个校准的模型，并且所产生的粒子被解释为多个源的空间路径密度分布。所采用的方法提供了优于传统点云方法的优势，传统点云方法不提供处理地下非均质性的不完全描述所产生的不确定性的方法。K场中的不确定性被显示为强烈影响空间路径分布。在头部观测的信息内容不足以约束估计参数的位置，路径扩展尤其明显。尽管预测存在不确定性，但研究地点的泵送饮用水很可能主要由源自当地渗透渠道的人工渗透地下水构成。该模型表明，在井场内，中央抽水井可以抽取区域地下水，尽管可能性相对较低。尽管如此，仍然需要进行严格的不确定性评估，因为只有少数几个认识导致了支持现场观察的流动路径。因此，模型结果不应仅基于一种模型实现；相反，应进行不确定性分析，以提供一套足够大的同等可能的模拟，包括所有潜在的来源和途径。
Assessing the Transport of Pharmaceutical Compounds in a Layered Aquifer Discharging to a Stream
评估向河流排放的分层含水层中药物化合物的迁移
A groundwater plume containing high concentrations of pharmaceutical compounds, mainly sulfonamides, barbiturates, and ethyl urethane, in addition to chlorinated ethenes and benzene was investigated. The contamination originating from a former pharmaceutical industry discharges into a multilayered aquifer system and a downgradient stream. In this study, geological and hydrogeological data were integrated into a numerical flow model to examine identified trends using statistical approaches, including principal component analysis and hierarchal cluster analysis. A joint interpretation of the groundwater flow paths and contaminant concentrations in the different compartments (i.e., groundwater and hyporheic zone) provided insight on the transport processes of the different contaminant plumes to the stream. The analysis of historical groundwater concentrations of pharmaceutical compounds at the site suggested these compounds are slowly degrading. The pharmaceutical compounds migrate in both a deep semiconfined aquifer, as well as in the shallow unconfined aquifer, and enter the stream along a 2‐km stretch. This contrasted with the chlorinated ethenes, which mainly discharge to the stream as a focused plume from the unconfined aquifer. The integrated approach developed here, combining groundwater flow modeling and statistical analyses of the contaminant concentration data collected in groundwater and the hyporheic zone, lead to an improved understanding of the observed distribution of contaminants in the unconfined and semiconfined aquifers, and thus to their discharge to the stream. This approach is particularly relevant for large and long‐lasting contaminant sources and plumes, such as abandoned landfills and industrial production sites, where field investigations may be very expensive.
对含有高浓度药物化合物(主要是磺胺类、巴比妥类和乙基氨基甲酸乙酯)以及氯化乙烯和苯的地下水羽流进行了研究。源自前制药工业的污染物排入多层含水层系统和下游。在这项研究中，地质和水文地质数据被整合到一个数值流模型中，以使用统计方法检查确定的趋势，包括主成分分析和层次聚类分析。对地下水流动路径和不同隔间(即地下水和地下水流带)中污染物浓度的联合解释，提供了不同污染物羽流向河流的传输过程。对该地点药物化合物的地下水历史浓度的分析表明，这些化合物正在缓慢降解。药物化合物既在深层半封闭含水层中迁移，也在浅层非封闭含水层中迁移，并沿2公里的长度进入河流。这与氯化乙烯形成对比，氯化乙烯主要以集中羽流形式从非承压含水层排放到河流中。此处开发的综合方法，结合地下水流动模型和地下水和地下水流带中收集的污染物浓度数据的统计分析，有助于更好地理解在非承压和半承压含水层中观察到的污染物分布，从而使污染物排放到河流中。这种方法特别适用于大型且持久的污染源和羽流，如废弃的垃圾填埋场和工业生产场所，在这些地方，实地调查可能非常昂贵。
Feasibility Assessment of Long‐Term Electrical Resistivity Monitoring of a Nitrate Plume
硝酸盐烟羽长期电阻率监测的可行性评估
Long‐term monitoring solutions at contaminated sites are necessary to track plume migration and evaluate the performance of remediation efforts. Electrical resistivity imaging (ERI) can potentially provide information about plume dynamics; however, the feasibility and likelihood of success are seldom evaluated before conducting a field study. Coupling flow and transport models with geoelectrical models provide a powerful way to assess the potential effectiveness of an actual ERI field campaign. We present a coupled approach for evaluating the feasibility of monitoring nitrate migration and remediation using 4D time‐lapse ERI at a legacy nuclear waste facility. This kilometer‐scale study focuses on depths below the water table (∼70 m). A flow and transport model is developed to perform simulations of nitrate migration and removal via a hypothetical pump‐and‐treat system. A tracer injection is also simulated at the leading edge of the nitrate plume to enhance the conductivity contrast between the native subsurface and the groundwater fluids. Images of absolute bulk conductivity provide limited information concerning plume migration while time‐lapse difference images, which remove the static effects of geology, provide more useful information concerning plume dynamics over time. A spatial moment analysis performed on flow and transport and ERI models matches well during the tracer injection; however, inversion regularization smoothing otherwise limits the value in terms of locating the center of mass. We find that the addition of a tracer enables ERI to characterize plume dynamics during pump‐and‐treat operations, and late‐time ERI monitoring provides a conservative estimate of nitrate plume boundaries in this synthetic study.
污染场地的长期监测解决方案对于跟踪羽流迁移和评估修复工作的绩效是必要的。电阻率成像(ERI)可能提供关于羽流动力学的信息；然而，在进行实地研究之前，很少评估成功的可行性和可能性。将流动和传输模型与地电模型相结合，为评估实际ERI油田活动的潜在有效性提供了一种强有力的方法。我们提出了一种耦合方法，用于评估在遗留核废料设施中使用4D延时ERI监测硝酸盐迁移和补救的可行性。这项千米级的研究主要关注地下水位以下的深度(∼70 m).开发了一个流动和传输模型，通过一个假设的泵送和处理系统来模拟硝酸盐的迁移和去除。还在硝酸盐卷流的前缘模拟示踪剂注入，以增强天然地下流体和地下水流体之间的电导率对比。绝对体积电导率的图像提供了关于羽流迁移的有限信息，而消除了地质静态影响的时移差图像提供了更多关于羽流随时间变化的有用信息。在示踪剂注入期间，对流动和输运模型以及ERI模型进行的空间矩分析匹配良好；然而，反演正则化平滑在定位质心方面限制了该值。我们发现，添加示踪剂使ERI能够表征泵和处理作业期间的羽流动力学，后期ERI监测提供了该合成研究中硝酸盐羽流边界的保守估计。
Hydraulic Tomography: 3D Hydraulic Conductivity, Fracture Network, and Connectivity in Mudstone
水力层析成像:三维水力传导度、裂缝网络和泥岩连通性
We present the first demonstration of hydraulic tomography (HT) to estimate the three‐dimensional (3D) hydraulic conductivity (K) distribution of a fractured aquifer at high‐resolution field scale (HRFS), including the fracture network and connectivity through it. We invert drawdown data collected from packer‐isolated borehole intervals during 42 pumping tests in a wellfield at the former Naval Air Warfare Center, West Trenton, New Jersey, in the Newark Basin. Five additional tests were reserved for a quality check of HT results. We used an equivalent porous medium forward model and geostatistical inversion to estimate 3D K at high resolution (K blocks <1 m3), using no strict assumptions about K variability or fracture statistics. The resulting 3D K estimate ranges from approximately 0.1 (highest‐K fractures) to approximately 10−13 m/s (unfractured mudstone). Important estimated features include: (1) a highly fractured zone (HFZ) consisting of a sequence of high‐K bedding‐plane fractures; (2) a low‐K zone that disrupts the HFZ; (3) several secondary fractures of limited extent; and (4) regions of very low‐K rock matrix. The 3D K estimate explains complex drawdown behavior observed in the field. Drawdown tracing and particle tracking simulations reveal a 3D fracture network within the estimated K distribution, and connectivity routes through the network. Model fit is best in the shallower part of the wellfield, with high density of observations and tests. The capabilities of HT demonstrated for 3D fractured aquifer characterization at HRFS may support improved in situ remediation for contaminant source zones, and applications in mining, repository assessment, or geotechnical engineering.
我们首次演示了水力层析成像(HT)，以在高分辨率现场规模(HRFS)下估算裂隙含水层的三维(3D)水力传导度(K)分布，包括裂隙网络和通过裂隙网络的连通性。我们在纽瓦克盆地新泽西西特伦顿前海军空战中心的一个井场进行了42次抽水试验，将从封隔器隔离井段收集的压降数据进行了反演。另外保留了五项测试用于高温试验结果的质量检查。我们使用了等效多孔介质正演模型和地质统计学反演来估算高分辨率下的三维k值(<1 m3 k区块),没有使用关于k可变性或裂缝统计的严格假设。由此得出的3D K估计值范围从大约0.1(最高K裂缝)到大约10-13米/秒(未断裂的泥岩)。重要的估计特征包括:(1)由一系列高钾层理面裂缝组成的高裂缝带(HFZ)；(2)扰乱HFZ的低钾区；(3)几条有限范围的次生裂缝；和(4)极低K岩石基质区域。3D K估计解释了现场观察到的复杂的水位下降行为。压降追踪和粒子追踪模拟揭示了在估计的K分布内的3D裂缝网络，以及通过网络的连接路径。模型拟合最好在井场较浅的部分，有高密度的观察和测试。在HRFS展示的用于3D裂隙含水层表征的高温处理能力可能支持污染源区域的改进原位修复，以及在采矿、储存库评估或岩土工程中的应用。
Transient and Transition Factors in Modeling Permafrost Thaw and Groundwater Flow
冻土融化和地下水流模拟中的瞬态和过渡因素
Permafrost covers approximately 24% of the Northern Hemisphere, and much of it is degrading, which causes infrastructure failures and ecosystem transitions. Understanding groundwater and heat flow processes in permafrost environments is challenging due to spatially and temporarily varying hydraulic connections between water above and below the near‐surface discontinuous frozen zone. To characterize the transitional period of permafrost degradation, a three‐dimensional model of a permafrost plateau that includes the supra‐permafrost zone and surrounding wetlands was developed. The model is based on the Scotty Creek basin in the Northwest Territories, Canada. FEFLOW groundwater flow and heat transport modeling software is used in conjunction with the piFreeze plug‐in, to account for phase changes between ice and water. The Simultaneous Heat and Water (SHAW) flow model is used to calculate ground temperatures and surface water balance, which are then used as FEFLOW boundary conditions. As simulating actual permafrost evolution would require hundreds of years of climate variations over an evolving landscape, whose geomorphic features are unknown, methodologies for developing permafrost initial conditions for transient simulations were investigated. It was found that a model initialized with a transient spin‐up methodology, that includes an unfrozen layer between the permafrost table and ground surface, yields better results than with steady‐state permafrost initial conditions. This study also demonstrates the critical role that variations in land surface and permafrost table microtopography, along with talik development, play in permafrost degradation. Modeling permafrost dynamics will allow for the testing of remedial measures to stabilize permafrost in high value infrastructure environments.
永久冻土覆盖了北半球大约24%的面积，其中大部分正在退化，这导致了基础设施的故障和生态系统的转变。由于近地表不连续冻结带上方和下方的水在空间上和时间上的水力联系不同，理解永久冻土环境中的地下水和热流过程具有挑战性。为了描述永久冻土退化的过渡期，开发了一个包括超永久冻土带和周围湿地的永久冻土高原三维模型。该模型基于加拿大西北地区的斯科特河流域。FEFLOW地下水流动和热量传输建模软件与piFreeze插件结合使用，以说明冰和水之间的相变。同时加热和水(SHAW)流动模型用于计算地面温度和地表水平衡，然后用作FEFLOW边界条件。由于模拟实际的永冻土演化需要在不断演化的地貌上经历数百年的气候变化，而地貌特征是未知的，因此研究了开发用于瞬态模拟的永冻土初始条件的方法。研究发现，用瞬态加速方法初始化的模型，包括永冻土带和地表之间的未冻结层，比稳态永冻土初始条件产生更好的结果。这项研究还证明了地表和永冻层微地形的变化以及talik开发在永冻层退化中的关键作用。永久冻土动力学建模将允许在高价值基础设施环境中测试稳定永久冻土的补救措施。
Assessing “Urban Karst” Effects from Groundwater–Storm Sewer System Interaction in a Till Aquitard
评估蓄水层中地下水-雨水管道系统相互作用的“城市岩溶”效应
Storm sewer systems and their associated utility trenches may strongly influence the effects of urbanization on a groundwater system. This study was undertaken to identify the causes of district‐wide basement infiltration in an aquitard system. It comprised widespread continuous monitoring of utility trench wells and dye tracing from storm sewer system exfiltration tests. The results indicate that a major effect of urbanization on shallow groundwater is related to storm sewer system exfiltration, which is marked by a characteristic pattern of head variations in the aquitard unrelated to distributed surface infiltration. The aquitard constrains flow from storm sewer system exfiltration to the utility trench, creating an urban flow path for groundwater discharge. Temporary buildup of water levels in the utility trench drives relatively high‐velocity flow through the permeable sewer bedding material of the utility trench to a separate foundation drainage collector system, ultimately causing a severe “urban karst” effect that produces system surcharging and widespread basement water infiltration. The main conditions causing the “urban karst” are the large hydraulic conductivity ratio between the utility trench material and the aquitard, and the shallow depth and low gradient of the storm sewer system imposed by a very flat drainage basin.
雨水管道系统及其相关的公用沟渠可能会强烈影响城市化对地下水系统的影响。本研究旨在确定弱透水系统中整个地区基底渗透的原因。它包括对公用管沟井的广泛连续监测和雨水管道系统渗漏测试的染料追踪。结果表明，城市化对浅层地下水的主要影响与雨水管道系统渗漏有关，雨水管道系统渗漏的特点是弱透水层中水头变化的特征模式与分布的地表入渗无关。弱透水性限制了雨水管道系统向公用沟渠的渗漏，为地下水排放创造了一条城市流路。公用设施沟渠中水位的暂时升高，促使相对高速的水流通过公用设施沟渠的可渗透下水道垫层材料，流向独立的基础排水收集器系统，最终导致严重的“城市岩溶”效应，产生系统超负荷和广泛的地下水渗透。造成“城市岩溶”的主要条件是公用沟渠材料和弱透水层之间的大的水力传导率，以及由非常平坦的排水盆地所造成的雨水管道系统的浅深度和低坡度。
Three‐Dimensional Numerical Investigation of Pore Water Pressure and Deformation of Pumped Aquifer Systems
抽水含水层系统孔隙水压力和变形的三维数值研究
Excessive groundwater withdrawal has caused severe land subsidence worldwide. The pore water pressure and the deformation of pumped hydrostratigraphic units are complex. A fully coupled three‐dimensional numerical simulation was carried out for different pumping plans in this paper. When groundwater is pumped from a confined aquifer, the great compaction occurs in the pumped aquifer and its upper and lower adjacent aquitard units. Land subsidence is smaller and the area affected by land subsidence is greater when groundwater is pumped from the deeper confined aquifer. The pore water pressure in the pumped confined aquifer changes immediately with pumpage. In the adjacent aquitard units, however, the pore water pressure increases in the early pumping time and decreases in the early recharging time. The decrease in the pore water pressure vertically spreads from the interface between aquitard and pumped aquifer to the other surface of the aquitard. The pumped aquifer compacts and rebounds immediately with pumping and non‐pumping or recharging actions, while the compaction and rebounding of the aquitard units clearly lag behind. The compaction of the adjacent aquitard unit first occurs near the interface between aquitard and pumped aquifer units, and the compaction zone spreads outward as the pumping goes on. The aquitards may expand vertically within some zones. Due to the inelastic deformation of soil skeleton, different pumping plans result in different land subsidence. For the same net pumpage, maximal land subsidence and horizontal displacement are the smallest for constant discharge and the greatest for recharge‐discharge cycle.
过量抽取地下水已经在世界范围内造成了严重的地面沉降。抽水地层单元的孔隙水压力和变形是复杂的。本文对不同的抽水方案进行了完全耦合的三维数值模拟。当从承压含水层抽取地下水时，被抽取的含水层及其上下相邻的弱透水层单元会产生巨大的压实作用。当从深层承压含水层抽取地下水时，地面沉降较小，受地面沉降影响的面积较大。泵送承压含水层中的孔隙水压力随着泵送而立即变化。然而，在相邻的弱透水层单元中，孔隙水压力在抽水初期增加，在回灌初期减小。孔隙水压力的降低从弱透水层和抽水含水层之间的界面垂直扩散到弱透水层的另一个表面。抽水含水层通过抽水和非抽水或回灌作用立即压实和回弹，而弱透水单元的压实和回弹明显滞后。邻近的弱透水层单元的压实首先发生在弱透水层单元和抽水含水层单元之间的界面附近，随着抽水的进行，压实带向外扩展。弱透水层可能在某些区域内垂直扩展。由于土骨架的非弹性变形，不同的抽水方案导致不同的地面沉降。对于相同的净抽水量，最大地面沉降和水平位移在恒定排放时最小，在补给-排放循环时最大。
Methods Note/方法研究
An Instrument for the Determination of a Hydropneumograph in a Bubbling Spring
一种用于测定冒泡弹簧中水血压计的仪器
In order to enable greater accuracy in the determination of the mass discharge of gas and water‐gas ratios (WGR) in groundwater from springs, we have developed a field‐deployable instrument using commercially available components to independently measure the gas and water mass flow rates in springs with bubbling mixed‐phase flow. Collecting and measuring the free gas phase will allow for further compositional analysis that may be useful in improving gas‐derived parameters such as recharge temperature and age, as well as quantification of methanogenesis and flux of crustal/mantle gasses. By installing a phase separator at the spring discharge, a thermal mass flow sensor is utilized to measure the gas flow rate (ebullition + flux) generated from a spring. The water flow rate is determined by a standard weir. Field performance of the device was tested on a spring discharging from the Arbuckle‐Simpson aquifer near the town of Connerville in south‐central Oklahoma, USA.
为了能够更准确地确定泉水中气体和水气比(WGR)的质量排放量，我们开发了一种现场可部署仪器，该仪器使用市场上可买到的部件来独立测量具有鼓泡混合相流的泉水中的气体和水的质量流量。收集和测量游离气相将有助于进一步的成分分析，这可能有助于改善气源参数，如补给温度和年龄，以及甲烷生成和地壳/地幔气体通量的量化。通过在弹簧出口处安装分相器，热质量流量传感器用于测量弹簧产生的气体流量(沸腾+流量)。水流量由标准堰决定。该装置的现场性能在美国俄克拉荷马州中南部康纳镇附近的阿巴克尔-辛普森含水层的泉水排放上进行了测试。
Case Study/案例研究
Simulation of Flow in a Complex Aquifer System Subjected to Long‐Term Well Network Growth
长期井网生长条件下复杂含水层系统的流动模拟
In west‐central Lower Peninsula of Michigan, population growth and expanded agricultural activities over recent decades have resulted in significant increases in distributed groundwater withdrawals. The growth of the extensive well network and anecdotes of water shortages (dry wells) have raised concerns over the region's groundwater sustainability. We developed an unsteady, three‐dimensional (3D) groundwater flow model to describe system dynamics over the last 50 years and evaluate long‐term impacts of groundwater use. Simulating this large aquifer system was challenging; the site is characterized by strong, spatially distributed, and statistically nonstationary heterogeneity, making it difficult to avoid over‐parameterization using traditional approaches for conceptualizing and calibrating a flow model. Moreover, traditional pumping and water level data were lacking and prohibitively expensive to collect given the large‐scale and long‐term nature of this study. An integrated, stochastic‐deterministic approach was developed to characterize the system and calibrate the flow model through innovative use of high‐density water well datasets. This approached allowed (1) implementation of a “zone‐based,” nonstationary stochastic approach to conceptualize complex spatial variability using a small set of geologic material types; (2) modeling the spatiotemporal evolution of many water well withdrawals across several decades using sector‐based parameterization; and (3) critical analysis of long‐term water level changes at different locations in the aquifer system for characterizing the system dynamics and calibrating the model. Results show the approach is reasonably successful in calibrating a complex model for a highly complex site in a way that honors complex distributed heterogeneity and stress configurations.
在密歇根州中西部的下半岛，近几十年来人口增长和农业活动的扩大导致分布式地下水开采量显著增加。广泛的井网的发展和水资源短缺的轶事(枯井)引起了对该地区地下水可持续性的关注。我们开发了一个不稳定的三维(3D)地下水流动模型来描述上一次50 years的系统动力学，并评估地下水使用的长期影响。模拟这一大型含水层系统具有挑战性；该站点的特点是强的、空间分布的和统计上非平稳的异质性，这使得使用传统方法概念化和校准流动模型很难避免过度参数化。此外，考虑到这项研究的大规模和长期性质，传统的抽水和水位数据是缺乏的，而且收集起来非常昂贵。开发了一种集成的随机确定性方法，通过创新性地使用高密度水井数据集来表征系统和校准流动模型。这种方法允许(1)采用“基于区域”的非平稳随机方法，使用一组小的地质材料类型来概念化复杂的空间变异性；(2)使用基于扇区的参数化对几十年间许多水井抽水的时空演化进行建模；(3)对含水层系统不同位置的长期水位变化进行临界分析，以表征系统动态并校准模型。结果表明，该方法在为高度复杂的现场校准复杂模型方面相当成功，其方式符合复杂的分布式异构性和压力配置。
来源：Groundwater官网
END
点击图片，爆款原创，以飨共赏达西环境
邮箱：darcyenv@yeah.net
办公微信：Darcy_Env
做地下水环境的医生！