灌区地表水—地下水耦合模型的构建

为了定量描述灌区水平衡要素及其转化关系,构建了灌区地表水-地下水分布式模拟耦合模型。通过改进SWAT模型的稻田及旱作物水分循环、蒸发蒸腾量和渠系渗漏计算等模块,建立了灌区地表水分布式模拟模型;以SWAT模型中的水文响应单元(HRU)和MODFLOW模型中的有限差分网格(cells)作为基本交换单元,将改进SWAT模型的地下水补给量计算值加载到MODFLOW模型的地下水补给模块,实现了灌区地表水-地下水分布式模拟模型的耦合。耦合模型在柳园口灌区的应用结果表明,该模型能够准确模拟和预测灌区地表水和地下水的动态变化,为灌区水管理提供了科学依据。     

基于ET的水资源与水环境综合规划研究（Ⅱ）- 模型

本文根据基于ET的区域水资源综合规划的理念、研究框架、目标及调控体系，构建了基于ET的区域水资源与水环境综合模拟模型（WQQCM），该模型由分布式水文SWAT模型、人工水平衡AWB模型及分布式地下水MODFLOW模型耦合而成，实现地表水和地下水、天然水循环和人工水循环、水量和水质联合模拟，作为区域水资源与水环境综合规划的工具。本文以天津市为例对模型从地表水径流、地表水水质、地下水以及模型模拟ET结果等方面进行了校验，校验结果表明模型可支撑不同节水、水资源配置、点源和非点源水污染控制、水生态修复规划方案的情景模拟，为区域水资源与水环境规划提供数据支撑。     

NUMERICAL MODELING OF WASTEWATER TRANSPORT AND DEGRADATION IN SOIL AQUIFER

1. INTRODUCTION The wastewater soil treatment system is an ecological treatment system where a self-adjustingand purification mechanism involving land soil– microorganism–plant ecology is formed to effectively treat the wastewater, meanwhile the nutrien…     

地下水数值模拟研究与应用进展

工农业的快速发展,使得大量污染物随着降雨径流入渗进入地下水,对地下水资源产生了严重威胁。由于对地下水污染物的实时监测具有一定难度和较高的经济成本,地下水模拟软件应运而生。系统分析了GMS、FEFLOW、Visual MODFLOW、Visual groundwater、MT3DMS、TOUGH2等地下水模拟软件的结构、模型求解方法、功能及优缺点等,总结了软件在水流、地下水水位和污染物运移数值模拟的应用进展。最后,进行了展望,提出地下水数值模拟软件与3S技术集成、与人工神经网络等系统预测方法结合、气候变化模型与多相模型及地表水-地下水模型等耦合开发以及结构优化等发展趋势。以期为地下水动力学和污染物运移模拟及海绵城市建设提供参考。     

Cyanotoxin transport from surface water to groundwater: Simulation scenarios for Lake Erie

Harmful algal bloom (HAB) and cyanotoxin studies in the Great Lakes region have been typically focused on surface-water issues, with few investigating or reporting on groundwater. This study aims to theoretically explore whether groundwater can be contaminated by microcystins from HABs in surface water due to surface-water and groundwater interaction. Specifically, a 3-D MODFLOW/MT3DMS model was developed to simulate pumping-induced reverse groundwater flow and solute transport from Lake Erie to the aquifer underneath the South Bass Island in Ohio. Our simulation results based on typical, base case settings showed that after microcystins were detected and released from the lake, it would take about two, three, and 13 months for the water in a well on the island to reach the EPA advisory levels of microcystin for detection (0.1 µg/l), infants and children (0.3 μg/l), and school-age children to adults (1.6 μg/l), respectively. Furthermore, our scenario analyses showed that, as expected, higher pumping rate and higher lakebed leakance would accelerate the microcystin transport to the well. However, higher hydraulic conductivity would increase the time to reach the EPA levels due to mixing and dilution effects. The 3-D modeling scheme developed in this study was suitable to simulate the complex surface-water and groundwater interaction and transport processes occurring in the Great Lakes. This theoretical study provides useful insight for managing coastal groundwater aquifers and resources under threat from HABs in the Great Lakes. Future improvements to the model would include incorporating reactions and fractures and obtaining water-quality data for model calibration.     

SWAT模型与MODFLOW模型的耦合计算及应用

为了准确模拟区域地下水动态变化,将地表水SWAT模型与地下水MODFLOW模型进行耦合计算。根据SWAT分布式模型的特点,以其水文响应单元(HRU)和MODFLOW模型的有限差分网格(cell)作为基本交换单元,将SWAT模型计算的地下水补给量和潜水蒸发量引入MODFLOW模型的地下水补给(RCH)模块和潜水蒸发(EVT)模块中,并将其应用于徐州市张集地区的地下水模拟计算。结果表明,SWAT模型与MODFLOW模型的耦合计算能准确模拟和预测该地区的地下水水情及其地表水和地下水之间的相互作用。     

Estimating Pumping Rates and Identifying Potential Recharge Zones for Groundwater Management in Multi-Aquifers System

Agricultural, aquaculture, industrial and domestic activities have placed enormous demands for water, which sometimes results in the over-pumping and associated continually declining groundwater levels. This in turn has led to land subsidence and soil salination. Therefore, it’s important to understand the local pumping activities or the pumping rates in order to implement appropriate water management. The distribution of pumping rates varies spatially and temporally due to the availability of surface water and seasonality. In addition, to have correct estimate of the pumping rates, both the hydrology and geology should be consider. SWAT and MODFLOW are employed and run separately to acquire certain hydrologic components such as the recharge, boundary flow and change of aquifer storage in multi-aquifers. The water balance method (WBM) is then adopted to estimate pumping rates with these components. To validate the proposed model the results of WBM and the official records are compared. Besides, in view of the serious land subsidence occurred, artificial recharge is regarded as an effective tool to alleviate and mitigate the subsidence. Nevertheless, the location of conducting artificial recharge needs to be identified first. The potential recharge zones are assessed based on the simulated recharge rates from SWAT and the spatial distribution of hydrological characteristics of the unconfined aquifer. Ultimately, an optimal recharge zone will be suggested. The proposed methodology is proved capable of estimating the pumping rates and locating the potential recharge zone.     

铜矿尾矿库污染物在地下水中运移规律数值模拟

尾矿库是矿山生产环节的必建场所,对周边生态环境有深远影响。以甘肃南畔铜矿为研究对象,运用Visual MODFLOW建立三维可视化水文地质模型,并通过MT3DMS溶质运移模块对4种特征污染物在无防渗和防渗破损两种非正常工况下进行污染物运移规律模拟和预测,从而验证尾矿库的可靠性,为尾矿库周边环境污染治理提供依据。结果表明:污染物在地下水中沿水流方向运移,随运移距离的增大,污染物浓度逐渐减小;总磷和氨氮运移距离远,对水环境的影响超过总砷和六价铬;相对于尾矿库无防渗,尾矿库采取防渗措施,可以有效降低对地下水污染的风险。     

Optimal Operation of Artificial Groundwater Recharge Systems Considering Water Quality Transformations

In water limited areas as water demand increases alternative sustainable water sources must be identified. One supply augmentation practice, that is already being applied in the arid southwest U.S., is artificial groundwater recharge usingwastewater effluent. The objective of a recharge facility is to supplement the available groundwater resources by storing water for the future. The resulting reclaimed water is used primarily for non-potable purposes but under increasing stressesshifting to potable use is likely to happen. Water quality thenbecomes a more pressing concern. Water quality improvements during infiltration and groundwater transport are significant and are collectively described as soil-aquifer treatment (SAT). To meet user needs, the recharge operation must be efficiently managed considering monetary, water quality and environmental concerns. In this paper, a SAT management model is developed that considers all of these concerns. Within the SAT management model, the shuffled complex evolution algorithm (SCE) is used as the optimization tool. SCEis a relatively new meta-heuristic search technique for continuousproblems that has been used extensively for hydrologic model calibration. In this application, SCE is integrated with the simulation models (MODFLOW, MT3D, and MODPATH) to represent movement and quality transformations. Two steady state case studies on a general hypothetical aquifer (modeled after a field site) were examined using the management model.     

基于广义ET的水资源与水环境综合规划研究Ⅱ:模型

在所提出的广义ET区域水资源综合规划的理念和研究框架基础上,本文构建了基于广义ET的区域水资源与水环境综合模拟模型,该模型由分布式水文SWAT模型、人工水平衡AWB模型及分布式地下水MODFLOW模型耦合而成,实现了地表水和地下水、天然水循环和人工水循环、水量和水质联合模拟。该模型可作为区域水资源与水环境综合规划的工具。以天津市为例,从地表水径流、地表水水质、地下水以及模型模拟ET结果等方面对模型进行了校验,校验结果表明模型可进行不同节水、水资源配置、点源和非点源水污染控制、水生态修复规划方案的情景模拟,为区域水资源与水环境规划提供支撑。     

典型污染场地含水层天然净化能力溶质模拟研究

根据典型石油类污染场地岩性、水文地质等特征,在长期观测、抽水试验及弥散试验等资料搜集与分析基础上,通过水流模型验证,构建了地下水水流运动及溶质迁移的数值模型。选取苯系物(BTEX)作为模拟因子,运用GMS软件中MT3DMS模块模拟地下水对流-弥散溶质迁移过程,运用RT3D模块模拟研究了地下水中移动、非移动的多种微生物共存的有机污染物生物降解过程。结果表明,生物降解化学反应具有明显的降低污染物峰值的作用,而研究区存在大量的好氧微生物作用和反硝化作用,据此提出可以采用原位生物修复技术来治理石油污染。     

二维强非均质含水层中渗透系数空间变异对污染物迁移的影响

对于强非均质介质,渗透系数的对数lnK的空间分布可表征为其增量遵从Levy稳定分布的非平稳随机场。本文利用改进的连续随机增量方法生成含水层lnK增量具有Levy稳定分布的统计特征的随机场;采用Monte-Carlo数值实验方法并结合MODFLOW与MT3DMS分别模拟研究区域内水流和溶质迁移过程,分析渗透系数强变异性对污染物浓度空间矩及宏观弥散的影响。结果表明:Levy指数α决定lnK的空间分布形状,宽度参数C则影响lnK的取值范围;污染物的质心位置与C、α的大小无关;C越大、α越小,污染物形状越不规则,污染物的扩散范围越大;且α越小,污染物具有明显的拖尾现象;纵向宏观弥散度随时间呈幂函数递增趋势。     

Integrated Modeling of Global Change Impacts on Agriculture and Groundwater Resources

The GLOWA-Danube research cooperation has developed the integrated simulation system DANUBIA to simulate water-related influences of global change in different spatial and temporal contexts. DANUBIA is a modular system comprised of 17 dynamically-coupled, process-based model components and a framework which controls the interaction of these components with respect to space and time. This article describes approaches and capabilities of DANUBIA with regard to the simulation of global change effects on agriculture and groundwater. To the agriculture-groundwater-relation, the direct effects that climate change has on the water balance are just as important as decisions made by land managers about land use and farming intensity. This article provides firstly a brief review of the research efforts which have been undertaken in the field of integrated modeling of agriculture and groundwater under conditions of global change. Then, the DANUBIA simulation framework and the associated DeepActor-framework for simulation of decision-making by agricultural actors are presented together with the model components which are most relevant to the interactions between agriculture and groundwater. The approach for developing combination climate and socio-economic scenarios is explained. Exemplary scenario results are shown for the Upper Danube Catchment in Southern Germany. Finally issues related to integrated simulation of global change effects on agriculture and groundwater are discussed.     

Assessment of lake–groundwater interactions and anthropogenic stresses,using numerical groundwater flow model,for a Rift lake catchment in central Ethiopia

A steady-state groundwater flow model (MODFLOW) was used to study lake and groundwater interactions in a complex rift volcanic catchment. It also was used to assess the effects of water pumping from wells, and of variable recharge rates associated with climate and lake level changes, on the dynamics of the volcanic aquifers surrounding Lake Awassa. The model simulations were made after first developing a reasonable conceptual model, on the basis of conventional hydrogeological mapping, pumping test and hydrometeorological data analyses, and from ancillary information obtained from hydrochemical and isotope techniques. The model results indicated that the lakes and Rift aquifers are fed by large groundwater inputs that originate in the highlands. The lakes and rivers have important roles in recharging the aquifers in some locations. Lake Awassa receives a major groundwater inflow from its southern and eastern shorelines, while substantial water leakage from the lake occurs along the northern shoreline. The annual groundwater outflow from the catchment is estimated to 52.5 × 10⁶ m³. Scenario analyses revealed that increasing the current pumping rate from wells by fourfold will substantially reduce the groundwater level substantially, although the regional flow pattern would remain the same. There appears to be no immediate danger to the Rift aquatic environment from the current water pumping rate. Drying the small Lake Shalo and associated swamps, however, will cause a large change in the water balance of the larger Lake Awassa. Slight changes in groundwater recharge can cause large differences in groundwater levels for most of the Rift caldera floor far from the lake shores. This study provides a reasonable foundation for developing detailed transient predictive models, which can then readily be used as a decision support tool for development and implementation of sustainable water resources practices.     

An Integrating Approach for Conjunctive-Use Planning of Surface and Subsurface Water System

This study proposes an integrated approach to assess the performance of a conjunctive-use surface and subsurface water system. System dynamics serves as the main framework of the proposed conjunctive-use model, simulating the interaction between surface and subsurface water and the impact of various conjunctive-use alternatives on the system as a whole. This study assumes natural groundwater recharge as a water source to the system, and estimates its volume using geographic information system (GIS) tools, a groundwater simulation model (MODFLOW), and a parameter identification model (UCODE). This study assesses various conjunctive-use alternatives and analyzes the frequency of water shortage to illustrate how the recharge rate affects water supply reliability under the conjunctive-use framework. Simulation results indicate that conjunctive-use with artificial recharge indeed reduces the frequency of extreme water shortages. Results also reveal that artificial recharge is necessary to maintain groundwater conservation without overusing river flow. Although this study focuses on southern Taiwan, the proposed concepts and procedure are applicable to other areas with a similar conjunctive-use framework.     

Assessing an Enhanced Version of SWAT on Water Quantity and Quality Simulation in Regions with Seasonal Snow Cover

Winter soil-temperature simulations with soil and water assessment tool (SWAT) are generally inaccurate in snow-dominated areas of the word, because the existing empirically-based soil-temperature module in SWAT does not account for snow-insulation effects. This problem, in turn, leads to all subsequent projections including water flow and nutrient loading biased. To address this issue, a physically-based soil-temperature module was developed and incorporated into SWAT as an alternative to the empirical formulation, which was found generate better overall estimates of winter soil temperature in a previous study. In the current study, we continue to examine the modified version of SWAT performance on watershed modeling by making pairwise comparisons between the outputs from the original and modified versions of SWAT against related field measurements in a testing watershed. Results show that the physically-based soil-temperature formulation helps to dramatically improve SWAT estimations of base flow discharge and NO₃-N loading for the watershed as a result of improvement in modeled winter soil temperatures. Compared with the original version of SWAT, the new version of SWAT predicted overall lower surface runoff and soil moisture content, as well as higher percolation and lateral flow in winter, resulting in clear differences in modeled flow paths and fate of chemical pollutants. Adding a physically-based treatment of soil temperature in SWAT is an important generalization that has potential of making the model more relevant to snow-dominated areas of the world.     

An Integrated DSS for Groundwater Management Based on Remote Sensing. The Case of a Semi-arid Aquifer in Morocco

A Decision Support System has been set up as the result of a fruitful cooperation between several public and research institutions in the framework of a large cooperation program. The DSS aims to compare spatially and temporally sectorial water demands of the Haouz-Mejjate plain (Morocco) in regard to available surface and groundwater resources. It is composed of a tool for satellite estimation of Agricultural Water Demand (SAMIR), a tool for integrated water resources planning (WEAP) and a groundwater model (MODFLOW) each of them relying on a common Geographical Information System not described here. The DSS is operating on a monthly time scale. Agricultural water demand accounts for about 80?% of the total demand. In areas where groundwater abstraction is difficult to quantify by direct methods, multitemporal remote sensing associated to the FAO methodology is a simple and efficient alternative to estimate Evapotranspiration (ET). In this work, a monthly estimate of ET from irrigated areas is derived from freely available MODIS NDVI for the 2001?C2009 period. An important part of the paper deals with the validation of these estimates with eddy covariance flux measurements installed on different irrigated crops of the region. Results are satisfactory with a minus 6.5?% error per year on the monthly time scale. This preprocessing allows to dichotomize irrigated versus non-irrigated areas, and then, to estimate groundwater abstraction in subareas distinguishing by their operating modes: traditional, dam or privately irrigated. A dynamic linkage between MODFLOW and WEAP transfers the results of one model as input data to the other. The model restitutes both spatial and temporal variations in head charges and allows the calculation of the ground water balance. After calibration, piezometric validation is acceptable for the majority of the 21 head control points.     

Application of Integrated Hydrologic and River Basin Management Modeling for the Optimal Development of a Multi-Purpose Reservoir Project

Multi-purpose reservoir development have been always a big challenge for the management of water resources. This paper describes an integrated approach for investigating catchment hydrology in the development of a hydropower and a canal irrigation system based on model analyses. The investigation aims to adequately determine an optimal domestic and irrigation water resources allocation scheme based on an assessment of the reservoir water balance and capacity for hydropower. The soil and water assessment tool (SWAT) which characterizes basin hydrology and the water management and planning model MODSIM which provides a decision support system for water allocation optimization, were used in this study. The integrated approach was applied to Prek Te River basin in Cambodia. The water demand aspect was examined based on domestic water use, irrigation water, environmental flow, and water losses. An operational rule curve was developed for hydropower operation with respect to a power potential of 13 MW. Hydrologic modeling revealed 90 % dependable water of about 2.7 m³/s during the dry season and 214.3 m³/s during the wet season, indicative of a wet-season dependent reservoir for storage. Results from the 26-years simulation period also showed that diversions for domestic water and irrigation water supply were 92.3 % dependable for a 13 MW capacity hydropower development. The integrated approach was shown to be a valuable decision support tool for water resources management with the determination of an optimum policy for multi-purpose reservoir operation based on available basin water supply.     

GIS-Based Groundwater Management Model for Western Nile Delta

The limited availability of renewable fresh water is a major constraint on future agriculture and urban development in Egypt. The main water resource that Egypt has been depending on is the River Nile. Nowadays, the role of groundwater is steadily increasing and will cover 20% of the total water supply in the coming decades especially in the reclaimed areas along the desert fringes of the Nile Delta and Valley. Abstraction from groundwater in Egypt is dynamic in nature as it grows rapidly with the expansion of irrigation activities, industrialization, and urbanization. One of these areas is the Western Nile Delta in which the groundwater is exploited in many localities. To avoid the deterioration of the aquifer system in this area, an efficient integrated and sustainable management plan for groundwater resources is needed. Efficient integrated and sustainable management of water resources relies on a comprehensive database that represents the characteristics of the aquifer system and modeling tools to achieve the impacts of decision alternatives. In this paper, a GIS-based model has been developed for the aquifer system of the Western Nile Delta. The GIS provides the utilization of analytical tools and visualization capabilities for pre-and post-processing information involved in groundwater modeling for the study area. The developed model was calibrated for steady state and transient conditions against the historical groundwater heads observed during the last 20 yr. The calibrated model was used to evaluate groundwater potentiality and to test two alternative management scenarios for conserving the aquifer system in Western Nile Delta. In the first scenario, reducing the surface water inflow while increasing the annual abstraction from groundwater by about 450 million m³ and improving the irrigation system could increase the net aquifer recharge by about 5.7% and reduce the aquifer potentiality by about 91%. Constructing a new canal as a second management scenario could increase the annual aquifer potentiality by about 23%. The GIS-based model has been proven to be an efficient tool for formulating integrated and sustainable management plan.     

水管理措施对区域水盐动态的影响

以内蒙古河套灌区义长灌域永联试验区为背景,基于野外观测试验数据,利用Visual MODFLOW4.2地下水运动模拟软件建立了区域非饱和-饱和水流与溶质运移耦合模型,并运用该模型,分析了不同节水方案下区域水盐动态.结果表明:在实施渠道混凝土衬砌,总引水量为现状87%的节水方案下,总体积盐量与现状水平相当,耕地非饱和带积...