共查询到20条相似文献，搜索用时 593 毫秒
1.
自流井是井孔-含水层系统的一种典型水文地质现象, 但在地下水资源评价和管理模型中研究较少.目前地下水数值模拟对自流井的3种处理方法均不合理, 也缺乏验证.常规地下水流有限差分法既不能准确地求出抽水井的井中水位, 也不能准确地求出自流井的流量, 必须进行校正.考虑自流井周围的径向流, 通过与井点附近地下水流的解析解相结合, 提出了矩形网格有限差分模拟的自流井校正模型, 其中考虑了自流井周围含水层存贮量的释放.算例表明, 即使用千米级大尺度网格, 本校正模型也能够获得相当精确的自流井流量, 绝大多数情况下相对误差小于5%. 相似文献
2.
Hossein Banejad Hamid Mohebzadeh Mohammad Hossein Ghobadi Majid Heydari 《Journal of the Geological Society of India》2014,83(1):83-92
Numerical simulation of groundwater flow used for the estimation of hydraulic and hydrologic parameters which is an important tool for the management of aquifers. This study presents the results of a mathematical model developed for the simulation of groundwater flow in Nahavand plain aquifer in the southwest Hamadan province. For this purpose Groundwater Modeling Software (GMS) was used which supports the MODFLOW-2000 code. After gathering required data such as the hydrological, hydrogeological and topography maps, a 3D hydrogeological model of plain was constructed with borehole and surface elevation data. Then MODFLOW was used for simulation of flow. After initial simulation of the flow, the model was calibrated in steady state with trial-and-error and parameter estimation methods the observed head of groundwater table monitoring data of 1997. Results of calibration show that error between observed head and computed head is in allowable range. Also results of computed head with model show that groundwater flow is in the direction of the dominate slope (southeast to northwest). Finally MODPATH code which simulates advective transport of particles was used for estimation of flow path and source of contaminants. 相似文献
3.
This study evaluates the alternative conceptual models for groundwater modelling. A true model was created with a synthetic alluvial fan-plain hydrogeological framework. Various alternative conceptual models were evaluated for groundwater flow simulations. The first alternative model is a single aquifer layer model; the second alternative model is a 3-layer aquifer model; and the third model is a 5-layer model consisting of 3 aquifers separated by 2 aquitards. All models could fit very well to the observations with optimized values of hydraulic conductivities. However, the single aquifer layer model can only compute water balance components with good accuracy. The 3-layer aquifer model can be used for water balance computation and groundwater head simulation with small errors. The 5-layer model is capable of simulating water budget, groundwater head distribution and travel times with high accuracy. Multi-model analysis found only the 3rd alternative model superior. 相似文献
4.
Tianxin Li Hongqing Song Gang Huang Ying Bi Xiyao Li 《Environmental Earth Sciences》2014,72(11):4599-4606
In this paper, a simple but accurate method (generalized large well method) is presented to assess groundwater level trends during mine exploitation. This method includes a mathematical model of confined–unconfined well flow and a corresponding analytical solution. Based on the method, a case study was analyzed with data from the Yimin open-pit mine. As a result, the radius of groundwater level rose, along with the increase of the exploitation intensity. Moreover, a suitable value of pumping flow could be beneficial to understanding potential groundwater contamination concerns. Additionally, it has also been predicted that the groundwater level of the Yimin open-pit mine will change within the next 3 years. The Yimin open-pit mine case study demonstrates the validity of the analytical method explained herein. The presented methodology provides a theoretical foundation for assessment of groundwater changing trends in other open-pit mines with similar hydrogeological conditions. 相似文献
5.
Groundwater flow and the associated surface water flow are potential negative factors on underground tunnels. Early detection of environmental impacts on water resources is of significant importance to planning, design and construction of tunnel projects, as early detection can minimize accidents and project delays during construction. The groundwater modeling software package Groundwater Modeling System (GMS), which supports the groundwater numerical codes MODFLOW and FEMWATER, was utilized to determine the impact of tunneling excavation on the hydrogeological environment in a regional area around the tunnel and a local hot springs area, at the “Tseng-Wen Reservoir Transbasin Diversion Project”, in Taiwan. A hydrogeological conceptual model was first developed to simplify structures related to the site topography, geology and geological structure. The MODFLOW code was then applied to simulate groundwater flow pattern for the hydrogeological conceptual model in the tunnel area. The automated parameter estimation method was applied to calibrate groundwater level fluctuation and hydrogeological parameters in the region. Calibration of the model demonstrated that errors between simulated and monitored results are smaller than allowable errors. The study also observed that tunneling excavation caused groundwater to flow toward the tunnel. No obvious changes in the groundwater flow field due to tunnel construction were observed far away in the surrounding regions. Furthermore, the FEMWATER code for solving 3-D groundwater flow problems, in which hydrogeological characteristics are integrated into a geographic information system (GIS), is applied to evaluate the impact of tunnel construction on an adjacent hot spring. Simulation results indicated that the groundwater drawdown rate is less than the groundwater recharge rate, and the change to the groundwater table after tunnel construction was insignificant for the hot spring area. Finally, the groundwater flow obtained via the GMS indicated that the hydrogeological conceptual model can estimate the possible quantity of tunnel inflow and the impact of tunnel construction on the regional and local groundwater resources regime of the transbasin diversion project. 相似文献
6.
地下水数值模拟常受到模型不确定性、观测资料不确定性等多种不确定性因素的影响,对这些影响因素进行定量分析十分必要。将差分进化自适应梅特罗波利斯(Differential Evolution Adaptive Metropolis,DREAM)算法与MODFLOW模型结合应用于地下水数值模拟不确定性的定量分析。以模型结构概化、水位观测资料误差这两种重要不确定性来源为例,通过一个理想地下水流模型,系统分析两者对模型参数及模型输出结果不确定性的影响。研究结果表明:模型结构概化及水位观测资料误差共同引起了地下水数值模拟的不确定性,但模型结构概化起到了主控作用。模型结构概化合理时,模型参数及模型输出结果的不确定性较小,并随观测资料误差不确定性的增大而增大;模型结构概化不合理时,模型参数及模型输出结果主要受控于模型结构概化带来的影响,且不确定性显著增大;观测资料误差相同情况下,模型结构概化越接近于真实的水文地质条件,模型参数及模型输出结果的不确定性越小。 相似文献
7.
Groundwater Flow Simulation and its Application in Groundwater Resource Evaluation in the North China Plain,China 总被引：2，自引：0，他引：2
The purpose of this study is to establish a 3D groundwater flow modelling for evaluating groundwater resources of the North China Plain.First,the North China Plain was divided into three aquifers vertically through a characterization of hydrogeological conditions.Groundwater model software GMS was used for modeling to divide the area of simulation into a regular network of 164 rows and 148 lines.This model was verified through fitting of the observed and the simulated groundwater flow fields at deep and shallow layers and comparison between the observed and simulated hydrographs at 64 typical observation wells.Furthermore,water budget analysis was also performed during the simulation period(2002-2003).Results of the established groundwater flow model showed that the average annual groundwater recharge of the North China Plain during 1991 to 2003 was 256.68×10~8 m~3/yr with safe yield of groundwater resources up to 213.49×10~8 m~3/yr,in which safe yield of shallow groundwater and that of deep groundwater was up to 191.65×10~8 m~3/yr and 22.64×10~8 m~3/yr respectively.Finally,this model was integrated with proposal for groundwater withdrawal in the study area after commencement of water supply by South-North Water Transfer Project,aiming to predict the changing trend of groundwater regime.As indicated by prediction results,South-North Water Transfer Project,which is favorable for effective control of expansion and intensification of existing depression cone,would play a positive role in alleviation of short supply of groundwater in the North China Plain as well as maintenance and protection of groundwater. 相似文献
8.
Paola Gattinoni 《Natural Hazards》2009,50(1):161-178
The article deals with a tool for landslides susceptibility assessment as a function of the hydrogeological setting at different
scales. The study has been applied to a test area located in Southern Italy. First, a 3D groundwater flow model was implemented
for a large-scale area. The simulation of several groundwater conditions compared with the landslide activity map allows drawing
a hydrogeological susceptibility map. Then, a slope scale analysis was carried out for the Cavallerizzo landslide. For this
purpose, a 2D groundwater parametrical modeling was coupled with a slope stability analysis; the simulation was carried out
by changing the values of the main hydrogeological parameters (recharge, groundwater supply level, etc.). The results enabled
to connect the slope instability to some hydrogeological characteristics that are easy to survey and to monitor (e.g., rainfall,
piezometrical level, and spring discharge), pointing out the hazard thresholds with regards to different triggering phenomena. 相似文献
9.
Peiyue Li Hui Qian Jianhua Wu Hongwei Liu Xinsheng Lyu Hongbo Zhang 《Environmental Earth Sciences》2014,71(1):293-299
Global curve-fitting method (GCFM) is regarded as an effective approach in hydrogeological parameter estimation, as it integrates and uses pumping data and water recovery data of a transient pumping test for parameter estimation. The impacts of pumping duration on hydrogeological parameter estimation by GCFM were investigated in the present study using 2 in situ pumping tests and 24 simulated transient pumping tests. Empirical formulas for determining the optimal pumping duration were derived. The study results suggest that pumping duration will have impacts on the accuracy of hydrogeological parameter estimation. When pumping duration is longer than a certain period, relative errors of hydrogeological parameter estimation keep relatively stable within an acceptable limit. Therefore, it is unnecessary to continue the pumping for a very long time after the groundwater level has become stable. When the change rate of drawdown over time (γ) in an observation well located within a distance of 100 m to the pumping well reaches 0.134, the pumping can be stopped. If there are more than one observation wells in a pumping test, the smallest γ value should be selected to determine the optimal pumping duration. This research is meaningful in the instruction of pumping tests, and will reduce test costs greatly. 相似文献
10.
A new perturbation technique and finite-element method, which incorporates an undetermined-coefficients approach, is proposed to conduct stochastic simulation for problems of groundwater flow. Formulas of the mean value and variance of groundwater head are derived to exclude the process of computing the first and second-order derivatives of groundwater head with respect to stochastic variables (coefficient of transmissibility, storage coefficient, etc.) in the calculation process of common finite element methods. For ordinary stochastic groundwater problems, the statistical properties of groundwater head can be easily obtained by using the proposed method, which is especially efficient for the stochastic problems that have fewer input stochastic variables. A stochastic numerical simulation of a two-dimensional confined-groundwater flow problem has been conducted to validate effectiveness and determine the limitations of the proposed method. The results illustrate that the accuracy and efficiency of the method proposed are satisfactory, and that the computing time is shorter when there is a small number of input stochastic variables. 相似文献
11.
岛屿是我国领土的重要组成部分,对国家安全和国防军事意义非凡。岛屿的地下水资源尤为珍贵,地下水流场模拟是研究地下水分布规律的重要手段。水文地质条件复杂、可利用的观测井较少等原因,造成了基岩岛屿水文地质模型概化精度不高、初始条件难以获取等问题。为克服基岩岛屿地下水流场模拟的诸多困难,将珠海外伶仃岛作为研究区,利用数字高程模型数据开展地质地貌建模; 利用探地雷达法、直流电法与地质分析对岛屿进行探测,获取了地层数据; 采用地下水遥感评估法,利用实测井位数据,确定了地下水的初始水位,进而对基岩岛屿地下水流场进行建模; 最终,通过对外伶仃岛地下水流场的数值模拟得出地下水模拟流场图。岛上多个测点的探测水位值与模拟水位相关性较好,其拟合优度R2为0.872 2。由此可见,综合遥感、物探、水文地质手段等技术方法获取的数据,采用地下水模拟软件或程序实现基岩岛屿地下水流场的数值模拟,是基岩岛屿地下水资源研究的一个有效方法。 相似文献
12.
基于MODFLOW参数不确定性的地下水水流数值模拟方法 总被引：1，自引：0，他引：1
考虑到模型不确定性引起的地下水数值模拟不确定性对模拟过程的影响,在简要介绍含水层水文地质参数变异性研究进展和地质统计学的基础上,基于常用的确定性地下水流数值模拟软件MODFLOW开发了MODFLOW-Gslib软件,相较于传统的数值模拟方法,将地质统计学与数值模拟结合的方法能够模拟非均质含水层中的参数变异性问题。将MODFLOW-Gslib软件运用于模拟实例中,选择常见的不确定性因素进行模拟,并对其模拟产生的数据进行统计分析,结果表明,软件转化后的参数符合水文地质参数不确定性的相关特征;与原模拟结果进行对比,该软件能够更加真实地刻画含水层参数变异性特征。 相似文献
13.
A Study on Infiltration and Groundwater Development in the Influent Zone of the Perched Lower Yellow River 
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下载免费PDF全文 A three-dimension flow model based on the hydrogeological conditions within the influent zone of the Yellow River in Henan Province, Yuanyang, China, was set up using FEFLOW. The interaction of the Yellow River and the groundwater was simulated under various pumping scenarios. For the planned water supply area, simulation results indicate that, within 10 years’ pumping at a rate of 4.86′108m3/a, the shallow groundwater flow and infiltration from Yellow River will be stabilized . After 10 years pumping, the infiltration will increase to 3.22′108m3/a ?and take approximately 70% of the pumping water. 相似文献
14.
Hydraulic conductivity sometimes exhibits complicated spatial variation over a site. A thorough understanding of the spatial distributions of hydraulic conductivity helps to make deterministic models of groundwater more accurate. This study presents a novel procedure that combines simulated annealing algorithms (SA) and the shortest distance method (SD) with the modular three-dimensional groundwater flow model (MODFLOW). The procedure is applied to a hypothetical site with groundwater-monitoring wells to minimize the difference between simulated and observed hydraulic head for optimal zoning of the spatial distribution of hydraulic conductivity. The results of this optimal zoning method indicate that this new procedure not only improves the efficiency of optimization, but also increases the probability of finding the global optimum, minimizing the errors of the hydraulic head simulated by MODFLOW in two scenarios, one with known and the other with unknown hydraulic conductivity. The results also illustrated that the procedure can effectively determine and delineate hydrogeological zones. 相似文献
15.
A Simple Approach to Account for Radial Flow and Boundary Conditions When Kriging Hydraulic Head Fields for Confined Aquifers 总被引：2，自引：0，他引：2
The estimation and mapping of realistic hydraulic head fields, hence of flow paths, is a major goal of many hydrogeological studies. The most widely used method to obtain reliable head fields is the inverse approach. This approach relies on the numerical approximation of the flow equation and requires specifying boundary conditions and the transmissivity of each grid element. Boundary conditions are often unknown or poorly known, yet they impose a strong signature on the head fields obtained by inverse analysis. A simpler alternative to the inverse approach is the direct kriging of the head field using the measurements obtained at observation wells. The kriging must be modified to incorporate the available information. Use of the dual kriging formalism enables simultaneously estimating the head field, the aquifer mean transmissivity, and the regional hydraulic gradient from head data in steady or transient state conditions. In transient state conditions, an estimate of the storage coefficient can be obtained. We test the approach on simple analytical cases, on synthetic cases with solutions obtained numerically using a finite element flow simulator, and on a real aquifer. For homogeneous aquifers, infinite or bounded, the kriging estimate retrieves the exact solution of the head field, the exact hydrogeological parameters and the flow net. With heterogeneous aquifers, kriging accurately estimates the head field with prediction errors of the same magnitude as typical head measurement errors. The transmissivities are also accurately estimated by kriging. Moreover, if inversion is required, the kriged head along boundaries can be used as realistic boundary conditions for flow simulation. 相似文献
16.
地下水流系统理论和数值模拟技术分别是水文地质学的基本理论和技术方法,含水岩组的概化是地下水流系统分析和地下水数值模拟的重要基础,直接影响着数值模拟和水流系统分析的精度和可信度.为提高含水岩组概化的精度和可信度,提出一种含水岩组概化的新方法,即累积导水系数法.依据岩层厚度与渗透系数乘积累积值随深度的变化,以及水文地质剖面岩性分布的整体特征,概化含水介质结构.以玛纳斯河流域为例,应用该方法概化流域内的岩性剖面,结合GMS软件中TINS模块构建水文地质结构模型.结果表明,应用该方法概化后的含水层结构具有较好的合理性和仿真性,建立的三维模型很好地显示了研究区含水介质的空间展布特征,为建立地下水流模型奠定了良好的基础. 相似文献
17.
Understanding the transference of water resources within hydrogeological systems, particularly in coastal aquifers, in which groundwater discharge may occur through multiple pathways (through springs, into rivers and streams, towards the sea, etc.), is crucial for sustainable groundwater use. This research aims to demonstrate the usefulness of the application of conventional recharge assessment methods coupled to isotopic techniques for accurately quantifying the hydrogeological balance and submarine groundwater discharge (SGD) from coastal carbonate aquifers. Sierra Almijara (Southern Spain), a carbonate aquifer formed of Triassic marbles, is considered as representative of Mediterranean coastal karst formations. The use of a multi-method approach has permitted the computation of a wide range of groundwater infiltration rates (17–60%) by means of direct application of hydrometeorological methods (Thornthwaite and Kessler) and spatially distributed information (modified APLIS method). A spatially weighted recharge rate of 42% results from the most coherent information on physiographic and hydrogeological characteristics of the studied system. Natural aquifer discharge and groundwater abstraction have been volumetrically quantified, based on flow and water-level data, while the relevance of SGD was estimated from the spatial analysis of salinity, 222Rn and the short-lived radium isotope 224Ra in coastal seawater. The total mean aquifer discharge (44.9–45.9 hm3 year?1) is in agreement with the average recharged groundwater (44.7 hm3 year?1), given that the system is volumetrically equilibrated during the study period. Besides the groundwater resources assessment, the methodological aspects of this research may be interesting for groundwater management and protection strategies in coastal areas, particularly karst environments. 相似文献
18.
Sergey Grinevskiy Elena Filimonova Victor Sporyshev Vsevolod Samartsev Sergey Pozdniakov 《Hydrogeology Journal》2018,26(8):2753-2767
Groundwater pumping and changes in climate-induced recharge lead to lower groundwater levels and significant changes in the water balance of a catchment. Water previously discharged as evapotranspiration can become a source of pumpage. Neglecting this effect leads to overestimated streamflow depletion. A small river basin (Sudogda River Basin, Russia) with a boreal climate and with long-term records of groundwater head and streamflow rate (showing that the measured stream depletion is less than the pumping rate) was investigated. The role of evapotranspiration in the water balance was analyzed by a hydrogeological model using MODFLOW-2005 with the STR package; the annual variation in recharge was obtained with the codes Surfbal and HYDRUS. The Sudogda River Basin was classified according to landscape and unsaturated-zone texture classes, and for each classified zone, the unsaturated-zone flow simulation was used to calculate the annual recharge dynamics for the observation period. Calibration of the regional flow model was conducted using flow and head observations jointly for two steady-state flow conditions—natural (before pumping started) and stressed (pumping). The simulations showed that pumped water originates from three sources: intercepted baseflow (75% of the annual total pumping rate), the capture of groundwater evapotranspiration discharge plus increased groundwater recharge (17%), and induced stream infiltration (8%). Additionally, multi-year precipitation records were analyzed to detect any long-term recharge and pumping water-budget changes. The results showed that increasing groundwater recharge by natural precipitation leads to (1) decreased intercepted baseflow and induced streamflow infiltration and (2) increased intercepted evapotranspiration discharge, thereby reducing stream depletion. 相似文献
19.
为了探究水文地质结构对地下水流数值模拟的不确定性,可以运用随机模拟建立地下水位的预测模型。根据转移概率地质统计方法模拟多孔介质岩性分布,利用非线性规划的思路计算岩性与水文地质参数之间的关系,从而建立相对精确的随机水文地质参数场。将不同的水文地质参数场运用到MODFLOW中,得到不同的随机模拟结果。通过比较随机模型和确定模型的末流场拟合情况以及水位动态拟合图,发现确定模型和随机模型具有相似趋势,都能与实测流场拟合较好,但是随机模型更能体现真实的水文地质特征。对随机模型预测10年后的地下水水位做不确定性分析,得到水位平均变幅介于-5～5 m之间,且95%置信度水位变幅的平均上限线约为0.146 m。研究结果为决策者提供科学依据。 相似文献
20.
为抑制疏干排水造成的地下水水资源量衰减,并控制露天煤矿煤炭开采对地下水资源的影响范围,采用了水帷幕保水采煤技术。以某露天煤矿为背景,建立沙槽回灌平台进行物理实验,再通过数值方法对回灌区进行模拟计算,分析疏干–回灌水帷幕的形成和变化规律。物理实验方法观察到回灌水帷幕形成定水头边界,阻止漏斗扩展的过程,获得不同回灌水帷幕水头高度对注水量的影响和注水量与排泄量平衡的最佳水头。数值模拟获得物理模拟类似的结果,回灌水帷幕位置可以有效限定疏干降落漏斗范围,回灌水帷幕定水头高度与疏干区水位和疏干时间正相关;最大回灌量受帷幕定水头高度影响显著;回灌水帷幕距离采坑越远对阻隔帷幕外水源补给的作用越大。物理模拟和数值模拟表明,改变回灌水帷幕的位置或水头高度都可以使得矿坑的排水量与帷幕的注水量相等,这就可以最大限度减少疏干水的外排水量。研究表明,疏干–回灌水帷幕可望成为我国露天煤矿区保水采煤的实用模式。 相似文献