【研究】Groundwater | Volume 58, Issue 3
Groundwater Modeling and Beyond: MODFLOW‐and‐More‐2019 Special Issue
地下水建模与未来：MODFLOW-More-2019专题
by Matthew Tonkin Mary Hill Reed M. Maxwell Chunmiao Zheng
Decision Support Modeling: Data Assimilation, Uncertainty Quantification, and Strategic Abstraction
决策支持建模：数据同化、不确定性量化和策略概化
by John Doherty Catherine Moore
1.Flux‐Corrected Transport with MT3DMS for Positive Solution of Transport with Full‐Tensor Dispersion
全张量弥散输运正解的MT3DMS通量校正输运
by Shuo Yan Albert J. Valocchi
Solute transport is usually modeled by the advection‐dispersion‐reaction equation. In the standard approach, mechanical dispersion is a tensor with principal directions parallel and perpendicular to the flow vector. Since realistic scenarios include nonuniform and unsteady flow fields, the governing equation has full tensor mechanical dispersion. When conventional grid‐based numerical methods are used, approximation of the cross terms arising from the off‐diagonal terms cause nonphysical solution with oscillations. As an example, for the common scenario of contaminant input into a domain with zero initial concentration, the cross‐dispersion terms can result in negative concentrations that can wreak havoc in reactive transport applications. To address this issue, we use the well‐known flux‐corrected‐transport (FCT) technique for a standard finite volume method. Although FCT has most often been used to eliminate oscillations resulting from discretization of the advection term for explicit time stepping, we show that it can be adapted for full‐tensor dispersion and implicit time stepping. Unlike other approaches based on new discretization techniques (e.g., mimetic finite difference, nonlinear finite volume), FCT has the advantage of being flexible and widely applicable. Implementation of FCT requires solving an additional system of equations at each time step, using a modified “low order” matrix and a modified right‐hand‐side vector. To demonstrate the flexibility of FCT, we have modified the well‐known and widely used groundwater solute transport simulator, MT3DMS. We apply the new simulator, MT3DMS‐FCT, to several benchmark problems that suffer from negative concentrations when using MT3DMS. The new results are mass conservative and strictly nonnegative.
溶质运移通常用对流扩散反应方程来模拟。在标准方法中，机械弥散是张量，其主方向平行于垂直于流动矢量。由于现实情况包括不均匀和不稳定的流场，因此控制方程具有完整的张量机械弥散。当使用传统的基于网格的数值方法时，由非对角线项引起的交叉项的近似会导致非物理解的振荡。例如，对于污染物输入初始浓度为零的域的常见情况，交叉扩散项可能会导致负浓度，从而在反应性运输应用中造成严重破坏。为了解决这个问题，我们将众所周知的通量校正传输（FCT）技术用于标准有限体积方法。尽管FCT最常用于消除对流项离散化导致的显式时间步长引起的振荡，但我们证明了它可以适用于全张量弥散和隐式时间步长。与其他基于新离散化技术（例如，模拟有限差分，非线性有限体积）的方法不同，FCT具有灵活性强且可广泛应用的优势。FCT的实现要求在每个时间步上使用修正的“低阶”矩阵和修正的右侧向量来求解附加的方程组。为了证明FCT的灵活性，我们修改了广为人知的地下水溶质运移模拟器MT3DMS。我们将新的模拟器MT3DMS-FCT应用于使用MT3DMS时由于负浓度而遭受的几个基准测试问题。新的结果是大规模保守的，严格来说是非负的。
2. Hydraulic‐Head Formulation for Density‐Dependent Flow and Transport
将液压头公式运用于密度依赖的流量和运输
by Christian D. Langevin Sorab Panday Alden M. Provost
Density‐dependent flow and transport solutions for coastal saltwater intrusion investigations, analyses of fluid injection into deep brines, and studies of convective fingering and instabilities of denser fluids moving through less dense fluids typically formulate the groundwater flow equation in terms of pressure or equivalent freshwater head. A formulation of the flow equation in terms of hydraulic head is presented here as an alternative. The hydraulic‐head formulation can facilitate adaptation of existing constant‐density groundwater flow codes to include density‐driven flow by avoiding the need to convert between freshwater head and hydraulic head within the code and by incorporating density‐dependent terms as a compartmentalized “correction” to constant‐density calculations already performed by the code. The hydraulic‐head formulation also accommodates complexities such as unconfined groundwater flow and Newton‐Raphson solution schemes more readily than the freshwater‐head formulation. Simulation results are presented for four example problems solved using an implementation of the hydraulic‐head formulation in MODFLOW.
用于沿海咸水入侵调查，对深层盐水注入流体的分析以及对流指法和密度较大的流体在密度较小的流体中流动的不稳定性的研究的密度依赖的流量和运输解决方案通常用压力或等效淡水头来表示地下水流量方程。作为替代方案，此处介绍了以液压头为单位的流量方程式。液压头公式可以避免现有规范中的淡水头和液压头之间的转换，并通过将与密度有关的术语作为分隔的“校正”，从而有助于适应现有的恒定密度地下水流规则，以包括密度驱动的流量。到代码已经执行的恒定密度计算。与淡水头公式相比，液压头公式还可以适应复杂的情况，例如无限制的地下水流量和Newton-Raphson解决方案。给出了使用MODFLOW中的液压头公式实现解决的四个示例问题的仿真结果。
3. Importance of Spatial Resolution in Global Groundwater Modeling
空间分辨率在全球地下水建模中的重要性
by Robert Reinecke Alexander Wachholz Steffen Mehl Laura Foglia Christoph Niemann Petra Döll
Global‐scale gradient‐based groundwater models are a new endeavor for hydrologists who wish to improve global hydrological models (GHMs). In particular, the integration of such groundwater models into GHMs improves the simulation of water flows between surface water and groundwater and of capillary rise and thus evapotranspiration. Currently, these models are not able to simulate water table depth adequately over the entire globe. Unsatisfactory model performance compared to well observations suggests that a higher spatial resolution is required to better represent the high spatial variability of land surface and groundwater elevations. In this study, we use New Zealand as a testbed and analyze the impacts of spatial resolution on the results of global groundwater models. Steady‐state hydraulic heads simulated by two versions of the global groundwater model G3M, at spatial resolutions of 5 arc‐minutes (9 km) and 30 arc‐seconds (900 m), are compared with observations from the Canterbury region. The output of three other groundwater models with different spatial resolutions is analyzed as well. Considering the spatial distribution of residuals, general patterns of unsatisfactory model performance remain at the higher resolutions, suggesting that an increase in model resolution alone does not fix problems such as the systematic overestimation of hydraulic head. We conclude that (1) a new understanding of how low‐resolution global groundwater models can be evaluated is required, and (2) merely increasing the spatial resolution of global‐scale groundwater models will not improve the simulation of the global freshwater system.
对于希望改进全球水文模型（GHM）的水文学家来说，基于全球规模的梯度地下水模型是一项新的尝试。特别是，将此类地下水模型集成到GHM中可改善对地表水和地下水之间的水流以及毛细上升和蒸散的模拟。目前，这些模型无法在整个地球上充分模拟地下水位深度。与油井观测结果相比，模型性能不尽人意，这意味着需要更高的空间分辨率才能更好地代表陆地表面和地下水高程的高空间变异性。在这项研究中，我们将新西兰用作测试平台，并分析空间分辨率对全球地下水模型结果的影响。将两个版本的全球地下水模型G3M模拟的稳态水头与5弧分（9 km）和30弧秒（900 m）的空间分辨率进行了比较，并与坎特伯雷地区的观测结果进行了比较。还分析了其他三种具有不同空间分辨率的地下水模型的输出。考虑到残差的空间分布，较差的模型性能一般模式仍保持较高的分辨率，这表明仅模型分辨率的提高并不能解决诸如液压头的系统过高估计之类的问题。我们得出的结论是：（1）需要对如何评估低分辨率的全球地下水模型有新的认识，（2）仅增加全球规模的地下水模型的空间分辨率并不能改善全球淡水系统的模拟。
4.Integrated Hydrologic Modeling to Untangle the Impacts of Water Management During Drought
集成水文模型，以解决干旱期间水管理的影响
by Lauren M. Thatch James M. Gilbert Reed M. Maxwell
Over the past century, groundwater levels in California's San Joaquin Valley have dropped by more than 30 m in some areas mostly due to excessive groundwater extraction used to irrigate agricultural lands and sustain a growing population. Between 2012 and 2015, California experienced the worst drought in its recorded history, depleting surface water supplies and further exacerbating groundwater depletion in the region. Due to a lack of groundwater regulation, exact quantities of extracted groundwater in California are unknown and hard to quantify. Recent adoption of the Sustainable Groundwater Management Act has intensified efforts to identify sustainable groundwater use. However, understanding sustainable use in a highly productive agricultural system with an extremely complex surface water allocation system, variable groundwater use, and spatially extensive and diverse irrigation practices is no easy task. Using an integrated hydrologic model coupled with a land surface model, we evaluated how water management activities, specifically a suite of irrigation and groundwater pumping scenarios, impact surface water–groundwater fluxes and storage components and how those activities and the relationships between them change during drought. Results showed that groundwater pumping volume had the most significant impact on long‐term water storage changes. A comparison with total water storage anomaly (TWSA) estimates from NASA's Gravity Recover and Climate Experiment (GRACE) provided some insight regarding which combinations of pumping and irrigation matched the GRACE TWSA estimates, lending credibility to these scenarios. In addition, the majority of long‐term water storage changes during the recent drought occurred in groundwater storage in the deeper subsurface.
在过去的一个世纪中，加利福尼亚州圣华金河谷的地下水位在某些地区下降了30µm以上，这主要是由于用于灌溉农田和维持人口增长的过量开采地下水所致。在2012年至2015年之间，加利福尼亚州经历了有记录以来最严重的干旱，耗尽了地表水供应，并进一步加剧了该地区的地下水消耗。由于缺乏地下水管理，加利福尼亚的提取地下水的确切数量未知，并且难以量化。最近通过的《可持续地下水管理法》加大了努力，以查明可持续的地下水用途。但是，要想在具有极其复杂的地表水分配系统，可变的地下水利用以及空间广泛且多样化的灌溉方式的高产农业系统中了解可持续利用并非易事。我们使用综合的水文模型和土地表面模型，评估了水管理活动（特别是一系列灌溉和地下水抽取方案）如何影响地表水-地下水通量和存储成分，以及干旱期间这些活动及其之间的关系如何变化。结果表明，地下水的抽水量对长期储水量的变化影响最大。与NASA重力恢复和气候实验（GRACE）的总储水异常（TWSA）估计值的比较提供了一些见识，涉及哪些抽水和灌溉组合与GRACE TWSA估计值相匹配，从而为这些情况提供了可信度。另外，在最近的干旱期间，大多数长期的水存储变化发生在较深的地下地下水存储中。
5. Simulating Groundwater‐Streamflow Connections in the Upper Colorado River Basin
模拟科罗拉多河上游流域的地下水流联系
by Hoang Tran Jun Zhang Jean‐Martial Cohard Laura E. Condon Reed M. Maxwell
In mountain, snow driven catchments, snowmelt is supposed to be the primary contribution to river streamflows during spring. In these catchments the contribution of groundwater is not well documented because of the difficulty to monitor groundwater in such complex environment with deep aquifers. In this study we use an integrated hydrologic model to conduct numerical experiments that help quantify the effect of lateral groundwater flow on total annual and peak streamflow in predevelopment conditions. Our simulations focus on the Upper Colorado River Basin (UCRB; 2.8 × 105 km2) a well‐documented mountain catchment for which both streamflow and water table measurements are available for several important sub‐basins. For the simulated water year, our results suggest an increase in peak flow of up to 57% when lateral groundwater flow processes are included—an unexpected result for flood conditions generally assumed independent of groundwater. Additionally, inclusion of lateral groundwater flow moderately improved the model match to observations. The correlation coefficient for mean annual flows improved from 0.84 for the no lateral groundwater flow simulation to 0.98 for the lateral groundwater flow one. Spatially we see more pronounced differences between lateral and no lateral groundwater flow cases in areas of the domain with steeper topography. We also found distinct differences in the magnitude and spatial distribution of streamflow changes with and without lateral groundwater flow between Upper Colorado River Sub‐basins. A sensitivity test that scaled hydraulic conductivity over two orders of magnitude was conducted for the lateral groundwater flow simulations. These results show that the impact of lateral groundwater flow is as large or larger than an order of magnitude change in hydraulic conductivity. While our results focus on the UCRB, we feel that these simulations have relevance to other headwaters systems worldwide.
在山区，积雪驱动的集水区，融雪被认为是春季春季河流流量的主要贡献。在这些流域中，由于很难在具有深层含水层的复杂环境中监测地下水，因此没有对地下水的贡献进行充分记录。在这项研究中，我们使用综合水文模型进行数值实验，以帮助量化侧向地下水流量对预开发条件下年总流量和峰值流量的影响。我们的模拟集中在科罗拉多河上游流域（UCRB；2.8×105km2），这是一个有据可查的山区流域，对于该流域和地下水位的测量都可用于几个重要的子流域。对于模拟水年，我们的结果表明，包括横向地下水流量过程，峰值流量最多增加57％-对于通常被认为独立于地下水的洪水状况，这是一个出乎意料的结果。此外，包含横向地下水流量适度改善了模型与观测值的匹配。年平均流量的相关系数从无侧向地下水流量模拟的0.84提高到无侧向地下水流量模拟的0.98。在空间上，在地形较陡的区域中，横向和非横向地下水流情况之间的差异更加明显。我们还发现了上科罗拉多河子流域之间有或没有侧向地下水流的流量变化幅度和空间分布的明显差异。进行了一个敏感性测试，将水力传导率定标在两个数量级以上，以进行侧向地下水流模拟。这些结果表明，地下水侧向流动的影响与水力传导率的变化幅度一样大或更大。尽管我们的结果集中在UCRB上，但我们认为这些模拟与全球其他上游水源系统相关。
6.Machine‐Learning Methods for Water Table Depth Prediction in Seasonal Freezing‐Thawing Areas
季节性冻融地区地下水位深度机器学习方法
by David Krcmar Renata Flakova Ivana Ondrejkova Kamila Hodasova Daniela Rusnakova Zlatica Zenisova Martin Zatlakovic
Long‐term and accurate predictions of regional groundwater hydrology are important for maintaining environmental sustainability in arid agricultural areas that experience seasonal freezing and thawing where serious water‐saving measurements are used. In this study, we firstly developed a machine‐learning method by integrating a multivariate time series controlled auto‐regressive method and the ridge regression method (CAR‐RR) for water table depth modeling. We applied and evaluated this model in the Hetao Irrigation District, located in northwest China where the freezing‐thawing period is 5 months long. To train and validate the model, we used monthly data of water diversion, precipitation, evaporation, and drainage from 1995 to 2013. The CAR‐RR model yielded more accurate results than the support vector regression (SVR) and multiple linear regression (MLR) models did in the validation period. To extend the model applicability during freezing‐thawing periods, we included additional temperature information. We compared results obtained using temperature only during the freezing‐thawing period with results obtained without temperature, which showed that the input data of the temperature during the freezing‐thawing period significantly improved the model accuracy. To resolve the problem of capturing the peaks and troughs of CAR‐RR, we further developed an integrated CAR‐SVR model to consider the nonlinearity. The optimal model (CAR‐SVR) was then used to predict the water table depth under future water‐saving measurements. It demonstrated that water diversion was the most important factor affecting the water table depth. A water table depth with less than 3.64 billion m3 water diversion will result in risks of environment problems.
对区域地下水水文学的长期和准确的预测对于维持干旱农业地区（在这些地区使用季节性节水和融化的情况下）需要严格的节水措施来维持环境的可持续性至关重要。在这项研究中，我们首先通过将多元时间序列控制的自回归方法与岭回归方法（CAR-RR）相集成来开发地下水位深度模型，从而开发了一种机器学习方法。我们在中国西北地区的河套灌区应用并评估了该模型，该地区的冻融期长达5个月。为了训练和验证该模型，我们使用了1995年至2013年的分水，降水，蒸发和排水的月度数据。与支持向量回归（SVR）和多元线性回归（MLR）相比，CAR-RR模型产生的结果更准确。模型在验证期内完成。为了扩展模型在冻融期间的适用性，我们包括了附加的温度信息。我们将仅在冻融期间使用温度获得的结果与没有温度的结果进行了比较，这表明在冻融期间温度的输入数据显着提高了模型准确性。为了解决捕获CAR‐RR的峰谷的问题，我们进一步开发了一个集成的CAR‐SVR模型来考虑非线性。然后，使用最佳模型（CAR-SVR）来预测未来节水措施下的地下水位深度。结果表明，引水是影响地下水位深度的最重要因素。地下水位调水量不足36.4亿立方米将导致环境问题的风险。
7. Quasi‐Saturated Layer: Implications for Estimating Recharge and Groundwater Modeling
准饱和层：估算补给量和地下水模型的意义
by Roger D. Gonçalves Elias H. Teramoto Bruno Z. Engelbrecht Miguel A. Alfaro Soto Hung K. Chang Martinus Th. van Genuchten
This study presents an extension of the concept of “quasi‐saturation” to a quasi‐saturated layer, defined as the uppermost dynamic portion of the saturated zone subject to water table fluctuations. Entrapped air here may cause substantial reductions in the hydraulic conductivity (K) and fillable pore water. Air entrapment is caused by a rising water table, usually as a result of groundwater recharge. The most significant effects of entrapped air are recharge overestimation based on methods that use specific yield (Sy), such as the water table fluctuation method (WTF), and reductions in K values. These effects impact estimation of fluid flow velocities and contaminant migration rates in groundwater. In order to quantify actual groundwater recharge rates and the effects of entrapped air, numerical simulations with the FEFLOW (Version 7.0) groundwater flow model were carried out using a quasi‐saturated layer for a pilot area in Rio Claro, Brazil. The calculated recharge rate represented 16% of the average precipitation over an 8‐year period, approximately half of estimates using the WTF method. Air entrapment amounted to a fillable porosity of 0.07, significant lower that the value of 0.17 obtained experimentally for Sy. Numerical results showed that the entrapped air volume in the quasi‐saturated layer can be very significant (0.58 of the air fraction) and hence can significantly affect estimates of groundwater recharge and groundwater flow rates near the water table.
这项研究提出了将“准饱和”概念扩展到准饱和层的定义，准层是指受地下水位波动影响的饱和区的最高动态部分。此处夹带的空气可能会导致水力传导率（K）和可填充孔隙水大大降低。地下水入水通常是地下水位上升引起的空气滞留。截留空气的最显着影响是基于使用特定产量（Sy）的方法（例如地下水位波动方法（WTF））和K值降低的补给过高估计。这些影响影响流体流速和地下水中污染物迁移速率的估计。为了量化实际的地下水补给率和夹带的空气的影响，在巴西里约克拉罗的一个试验区，使用准饱和层对FEFLOW（7.0版）地下水流量模型进行了数值模拟。计算得出的补给率代表了8年期间平均降水量的16％，大约是使用WTF方法估算的一半。空气截留的可填充孔隙率为0.07，大大低于通过实验获得的Sy值0.17。数值结果表明，准饱和层中夹带的空气量可能非常大（空气分数的0.58），因此会显着影响地下水位附近地下水补给量和地下水流量的估算。
8. Modification of the DRASTIC Framework for Mapping Groundwater Vulnerability Zones
修改DRASTIC框架进行地下水脆弱区的刻画
The DRASTIC technique is commonly used to assess groundwater vulnerability. The main disadvantage of the DRASTIC method is the difficulty associated with identifying appropriate ratings and weight assignments for each parameter. To mitigate this issue, ratings and weights can be approximated using different methods appropriate to the conditions of the study area. In this study, different linear (i.e., Wilcoxon test and statistical approaches) and nonlinear (Genetic algorithm [GA]) modifications for calibration of the DRASTIC framework using nitrate (NO3) concentrations were compared through the preparation of groundwater vulnerability maps of the Meshqin‐Shahr plain, Iran. Twenty‐two groundwater samples were collected from wells in the study area, and their respective NO3 concentrations were used to modify the ratings and weights of the DRASTIC parameters. The areas found to have the highest vulnerability were in the eastern, central, and western regions of the plain. Results showed that the modified DRASTIC frameworks performed well, compared to the unmodified DRASTIC. When measured NO3 concentrations were correlated with the vulnerability indices produced by each method, the unmodified DRASTIC method performed most poorly, and the Wilcoxon–GA–DRASTIC method proved optimal. Compared to the unmodified DRASTIC method with an R2 of 0.22, the Wilcoxon–GA–DRASTIC obtained a maximum R2 value of 0.78. Modification of DRASTIC parameter ratings was found to be more efficient than the modification of the weights in establishing an accurately calibrated DRASTIC framework. However, modification of parameter ratings and weights together increased the R2 value to the highest degree.
DRASTIC技术通常用于评估地下水的脆弱性。DRASTIC方法的主要缺点是难以确定每个参数的适当等级和权重。为了缓解此问题，可以使用适合研究区域条件的不同方法来对等级和权重进行近似估算。在这项研究中，通过准备Meshqin-的地下水脆弱性图，比较了使用硝酸盐（NO3）浓度校准DRASTIC框架的不同线性（即Wilcoxon检验和统计方法）和非线性（遗传算法[GA]）修改方法。伊朗沙尔平原。从研究区域的井中收集了22个地下水样品，并使用它们各自的NO3浓度来修改DRASTIC参数的等级和权重。发现的脆弱性最高的地区是平原的东部，中部和西部地区。结果表明，与未修饰的DRASTIC相比，修饰的DRASTIC框架表现良好。当测得的NO3浓度与每种方法产生的脆弱性指数相关时，未经修饰的DRASTIC方法表现最差，Wilcoxon–GA–DRASTIC方法证明是最佳方法。与R2为0.22的未经修改的DRASTIC方法相比，Wilcoxon–GA–DRASTIC获得的最大R2值为0.78。发现在建立精确校准的DRASTIC框架时，修改DRASTIC参数等级比权重修改更有效。但是，参数额定值和权重的修改一起将R2值提高到最高程度。
9. Modeling a Large‐Scale Historic Aquifer Test: Insight into the Hydrogeology of a Regional Fault Zone
模拟大规模历史含水层试验:对区域断裂带水文地质的洞察
Faults can act as flow barriers or conduits to groundwater flow by introducing heterogeneity in permeability. We examine the hydrogeology of the Sandwich Fault Zone, a 137 km long zone of high‐angle faults in northern Illinois, using a large‐scale historic aquifer test. The fault zone is poorly understood at depth due to the majority of the faults being buried by glacial deposits and its near‐vertical orientation which limits geologic sampling across faults. The aquifer test—perhaps one of the largest in terms of overall withdrawal in North American history—was conducted in 1942 at a facility adjacent to the fault zone. More than 34,000 m3/day was pumped for 37 days from nine multiaquifer wells open to the stratified Cambrian‐Ordovician sandstone aquifer system. We modeled the aquifer test using a transient MODFLOW‐USG model and simulated pumping wells with the CLN package. We tested numerous fault core/damage zone conceptualizations and calibrated to drawdown values recorded at production and observation wells. Our analysis indicates that the fault zone is a low‐permeability feature that inhibits lateral movement of groundwater and that there is at least an order of magnitude decrease in horizontal hydraulic conductivity in the fault core compared to the undeformed sandstone. Large head declines have occurred north of the fault zone (over 300 m since predevelopment conditions) and modifying fault zone parameters significantly affects calibration to regional drawdown on a decadal scale. The flow‐barrier behavior of the fault zone has important implications for future groundwater availability in this highly stressed region.
通过引入渗透率的非均质性，断层可以作为地下水流动的障碍或管道。我们使用大型历史含水层试验研究了伊利诺伊州北部高夹角断层长137 km的Sandwich断层带的水文地质。由于大部分断层都被冰川沉积物掩埋，并且其垂直方向接近，这限制了跨断层的地质取样，因此在深度上对断层带了解甚少。含水层测试-可能是北美历史上最大的整体抽水测试之一-于1942年在邻近断层带的设施中进行。从9口多层含水层井中抽出了34,000立方米/天的水，抽水了37 d天，这些井通往分层的寒武纪-奥陶纪砂岩含水层系统。我们使用瞬态MODFLOW-USG模型对含水层测试进行了建模，并使用CLN软件包模拟了抽水井。我们测试了许多断层岩心/破坏带概念，并根据在生产井和观察井记录的压降值进行了校准。我们的分析表明，断层带是低渗透率的特征，它抑制了地下水的横向运动，并且与未变形的砂岩相比，断层岩心中的水平水力传导率至少降低了一个数量级。在断层带以北发生了较大的水头下降（自开发前条件以来超过了300 m），修改断层带参数会显着影响年代际尺度上区域回缩的校准。断层带的阻流行为对这个高应力地区未来的地下水供应具有重要意义。
10.Assessing the Impact of a Heated Basement on Groundwater Temperatures in Bratislava, Slovakia
在斯洛伐克的布拉迪斯拉发评估地下室受热对地下水温度的影响
Groundwater temperature is a useful hydrogeological parameter that is easy to measure and can provide much insight into groundwater flow systems, but can be difficult to interpret. For measuring temperature directly in the ground, dedicated specifically designed monitoring wells are recommended since conventional groundwater wells are not optimal for temperature monitoring. Multilevel monitoring of groundwater temperature is required to identify contributions of different possible heat inputs (sources) on measured temperature signals. Interpreting temperature data as a cosine function, including period, average temperature, amplitude, and phase offset, is helpful. Amplitude dampening and increasing phase shift with distance from a boundary can be used for estimation of transport parameters. Temperature measurements at different depths can be used for evaluation of unknown parameters of analytical functions by optimization of regression fits in Python. These estimated parameters can be used to calculate temperatures at known water table depths which can be applied as a fixed transient boundary condition in MT3DMS to overcome the limitations of MT3DMS heat transport modeling in the unsaturated zone. In this study, temperature monitoring and modeling was used to evaluate the influence of a department store's heated basement foundation on groundwater temperature within a green space (city park), with the main outcome that 17 years after construction, the department store foundation has increased the mean groundwater temperature by 3.2 °C. Heat input evaluated by the MT3DMS model varied from 0.1 W/m2 at a distance of 100 m up to 12 W/m2 next to the building.
地下水温度是一种有用的水文地质参数，易于测量，可以深入了解地下水流动系统，但可能难以解释。为了直接在地下测量温度，建议使用专用的专门设计的监测井，因为常规的地下水井并不是温度监测的最佳选择。需要对地下水温度进行多级监控，以识别不同的可能热量输入（源）对测得的温度信号的影响。将温度数据解释为余弦函数，包括周期，平均温度，幅度和相位偏移，将很有帮助。振幅衰减和随着距边界的距离而增加的相移可用于估计传输参数。通过优化Python中的回归拟合，可以将不同深度处的温度测量结果用于评估解析函数的未知参数。这些估计的参数可用于计算已知水位深度的温度，该温度可用作MT3DMS中的固定瞬态边界条件，以克服非饱和区MT3DMS传热建模的局限性。在这项研究中，温度监测和建模被用来评估百货公司加热地下室基础对绿色空间（城市公园）内地下水温度的影响，其主要结果是，在施工17年后，百货商店基础增加了平均地下水温度为3.2C。MT3DMS模型评估的热量输入从100 m处的0.1 W / m2到建筑物附近的12 W / m2的变化。
11.Pay the PIED Piper: Guidelines to Visualize Large Geochemical Datasets on Piper Diagrams
付费使用PIED Piper：在Piper图上可视化大型地球化学数据集的准则
The Piper diagram has increased in popularity since its 1944 introduction and is now one of the most familiar and effective tools in the hydrogeologist's toolbox. Within the Piper diagram, three points on three related plots fully display the major ionic species of a water sample. Recently the size and availability of datasets have increased as additional field measurements and modeling results are shared more effectively in online databases. This growth presents opportunities and challenges for data analysis and conveyance—larger and longer datasets increase the potential to identify trends and patterns, but traditional Piper diagrams are quickly overwhelmed by large datasets as dense points overlap and become obscured. We present guidelines for effectively displaying large geochemical datasets on traditional Piper diagrams and new code that adds novel functionality for following these generic guidelines. This code, plotting interesting environmental data with Piper diagrams (PIED Piper), can be run within the Matlab environment or through a stand‐alone graphical user interface, and is the first Matlab code to generate Piper diagrams. The illustrative examples herein demonstrate (1) how limitations in displays of large datasets may be overcome with translucent symbology, contours, and heatmaps to identify trends and patterns, (2) how clusters of similar points can be identified and differentiated with convex hulls, and (3) how temporal‐and‐spatial patterns may be visually diagnosed with image groups and movies. The guidelines discussed in these examples will aid PIED Piper users to achieve the two goals of effective big data visualization: analysis and communication.
自1944年问世以来，Piper图已越来越受欢迎，现在已成为水文地质学家工具箱中最熟悉，最有效的工具之一。在Piper图中，三个相关图上的三个点完全显示了水样品中的主要离子种类。最近，随着在线数据库中更有效地共享其他现场测量结果和建模结果，数据集的大小和可用性有所增加。这种增长为数据分析和传输带来了机遇和挑战—越来越大的数据集增加了识别趋势和模式的潜力，但是随着密集点的重叠并变得模糊，传统的Piper图很快就被大型数据集淹没。我们提供了在传统Piper图上有效显示大型地球化学数据集的准则，以及为遵循这些通用准则而增加了新颖功能的新代码。该代码可以用Piper图（PIED Piper）绘制有趣的环境数据，可以在Matlab环境中或通过独立的图形用户界面运行，并且是第一个生成Piper图的Matlab代码。本文的说明性示例演示（1）如何通过半透明的符号系统，轮廓和热图克服大型数据集显示中的局限性，以识别趋势和模式；（2）如何用凸包识别和区分相似点的群；（3）如何通过图像组和电影视觉诊断时空模式。这些示例中讨论的准则将帮助PIED Piper用户实现有效的大数据可视化的两个目标：分析和交流。
12.Groundwater Complexity in Urban Catchments: Shenzhen, Southern China
城市集水区的地下水复杂性：中国深圳
by Michele Lancia Chunmiao Zheng Xin He David N. Lerner Charles Andrews
Groundwater interactions with surface water and sewers in an urban setting are complex, and classic hydrogeological approaches must be combined with anthropogenic elements to characterize them. The level of detail needed to understand these interactions is illustrated by the analysis of an urban subcatchment in the megacity of Shenzhen in southern China that has had a drastic urban expansion in the last 40 years. The study area is characterized by the Yanshanian granite that is widespread across southern‐eastern China. The urban setting is studied using multitemporal analysis of satellite images, borehole investigations and field surveys. Given the local hydrostratigraphy, a conceptual model was developed to identify the physical and anthropogenic factors that regulate the urban groundwater system. Based on the conceptual model and the data collected from the field or compiled from the literature, the average annual effective recharge is estimated to be 290 mm/year, after the urbanization process. From rural to urban conditions, it is estimated that the effective recharge increased by 170% and sewers intercept at least 23% of the effective recharge. Groundwater captured by sewers reduces river flows and increases the required capacity and costs for waste water treatment plants.
在城市环境中，地下水与地表水和下水道的相互作用非常复杂，必须将经典的水文地质方法与人为因素相结合来表征它们。通过分析中国南方特大城市的城市子汇水区，了解了这些相互作用所需要的详细程度，在过去的40多年中，该城市的城市规模急剧扩大。研究区以燕山期花岗岩为特征，该花岗岩分布于中国东南部。使用卫星图像的多时相分析，井眼调查和野外调查来研究城市环境。根据当地的水文地层学，开发了一个概念模型来确定调节城市地下水系统的物理和人为因素。根据概念模型和从野外收集或从文献中收集的数据，在城市化进程后，年均有效补给量估计为290 mm /年。从农村到城市，估计有效补给量增加了170％，下水道截留了至少23％的有效补给量。下水道收集的地下水减少了河流流量，并增加了污水处理厂所需的处理能力和成本。
来源：Groundwater官网
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