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1.
Development of a simple method for determining the influence radius of a pumping well in steady-state condition 
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下载免费PDF全文 A S El-Hames 《地下水科学与工程》2020,8(2):97-107
Influence radius of a pumping well is a crucial parameter for hydrogeologists and engineers. Knowing the radius of influence for a designed drawdown enables one to calculate the pumping rate required to layout a project foundation that may need lowering of groundwater level to a certain depth due to dewatering operation. In addition, this is important for hydrogeologists to determine ground water contamination flow paths and contributing recharge area for domestic water supply and aquifer management purposes. Empirical formulas that usually neglect vital parameters to determine the influence radius accurately have been traditionally utilized due to lack of adequate methods. In this study, a physically based method, which incorporates aquifer hydraulic gradient for determining the influence radius of a pumping well in steady-state flow condition, was developed. It utilizes Darcy and Dupuit laws to calculate the influence radius, where Darcy's law and Dupuit equation, in steady-state condition, represent the inflow and the outflow of the pumping well, respectively. In an untraditional manner, this method can be also used to determine aquifer hydraulic conductivity as an alternative to other pumping test methods with high degree of accuracy. The developed method is easy to use; where a simple mathematical calculator may be used to calculate the influence radius and the pumping rate or hydraulic conductivity. By comparing the results from this method with the MODFLOW numerical model outputs with different simulated scenarios, it is realized that this method is much superior and more advantageous than other commonly used empirical methods. 相似文献
2.
Multi-borehole pumping and tracer tests on the 10 to 100-m scale were conducted in a fractured chalk aquitard in the Negev
Desert, Israel. Outcrop and core fracture surveys, as well as slug tests in packed-off intervals, were carried out at this
site to obtain the parameters needed for construction of a stochastic discrete fracture network (DFN). Calibration of stochastic
DFNs directly to the multiple borehole test data was inadequate. Instead, two equivalent deterministic DFN flow models were
used: the vertical-fractures (VF) model, consisting of only vertical fractures, and the fractures’ intersections (INT) model,
consisting of vertical and horizontal fractures with enhanced transmissivity at their intersections. Both models were calibrated
against the multi-borehole response of one pumping test and their predictions were tested against three other independent
pumping tests. The average accuracies of all transient drawdown predictions of the VF and INT models were 65 and 66%, respectively.
In contrast to this equality in average drawdown predictions of both models, the INT model predicted better important breakthrough
curve features (e.g., first and peak arrival times), than the VF model. This result is in line with previously assumed channeled
flow, derived from analytical analysis of these pumping and tracer tests.
Ronit Nativ, deceased, may her memory be blessed. 相似文献
3.
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
4.
Gowri Srinivasan Elizabeth Keating John David Moulton Zora V. Dash Bruce A. Robinson 《Computational Geosciences》2012,16(3):551-563
A convolution-based particle tracking (CBPT) method was recently developed for calculating solute concentrations (Robinson
et al., Comput Geosci 14(4): 779–792, 2010). This method is highly efficient but limited to steady-state flow conditions. Here, we present an extension of this method
to transient flow conditions. This extension requires a single-particle tracking process model run, with a pulse of particles
introduced at a sequence of times for each source location. The number and interval of particle releases depends upon the
transients in the flow. Numerical convolution of particle paths obtained at each release time and location with a time-varying
source term is performed to yield the shape of the plume. Many factors controlling transport such as variation in source terms,
radioactive decay, and in some cases linear processes such as sorption and diffusion into dead-end pores can be simulated
in the convolution step for Monte Carlo-based analysis of transport uncertainty. We demonstrate the efficiency of the transient
CBPT method, by showing that it requires fewer particles than traditional random walk particle tracking methods to achieve
the same levels of accuracy, especially as the source term increases in duration or is uncertain. Since flow calculations
under transient conditions are often very expensive, this is a computationally efficient yet accurate method. 相似文献
5.
Philip T. Harte 《Environmental Earth Sciences》2017,76(6):251
A common assumption with groundwater sampling is that low (<0.5 L/min) pumping rates during well purging and sampling captures primarily lateral flow from the formation through the well-screened interval at a depth coincident with the pump intake. However, if the intake is adjacent to a low hydraulic conductivity part of the screened formation, this scenario will induce vertical groundwater flow to the pump intake from parts of the screened interval with high hydraulic conductivity. Because less formation water will initially be captured during pumping, a substantial volume of water already in the well (preexisting screen water or screen storage) will be captured during this initial time until inflow from the high hydraulic conductivity part of the screened formation can travel vertically in the well to the pump intake. Therefore, the length of the time needed for adequate purging prior to sample collection (called optimal purge duration) is controlled by the in-well, vertical travel times. A preliminary, simple analytical model was used to provide information on the relation between purge duration and capture of formation water for different gross levels of heterogeneity (contrast between low and high hydraulic conductivity layers). The model was then used to compare these time–volume relations to purge data (pumping rates and drawdown) collected at several representative monitoring wells from multiple sites. Results showed that computation of time-dependent capture of formation water (as opposed to capture of preexisting screen water), which were based on vertical travel times in the well, compares favorably with the time required to achieve field parameter stabilization. If field parameter stabilization is an indicator of arrival time of formation water, which has been postulated, then in-well, vertical flow may be an important factor at wells where low-flow sampling is the sample method of choice. 相似文献
6.
抽出 -处理系统设计多侧重于考虑修复初期的效率,在修复后期通常效率低下,产生拖尾现象,其优化的关键在于布设的井群系统能否高效抽出受污染的地下水体。利用溶质运移数值模拟可为井群布设和抽水方案优化提供依据。本研究旨在优化我国北方某化肥厂高浓度氨氮污染的地下水体的抽出 -处理修复系统,节约时间和成本。在水文地质调查及氨氮浓度监测的基础上,综合考虑井数、抽水天数和总抽水量三个变量,采用中轴线法与三角形法结合的布井方法,利用GMS软件反复试算,筛选出三种较优抽水方案并进一步模拟优化,最终从中选出最优抽水方案。结果,相比最初方案（方案1）,最优方案（方案3）将修复周期缩短了23个月,抽水总量减少了约31.9×104 m3,而抽水井数量仅增加了1口。该模型进行了稳定流水位拟合验证和4期非稳定流实测溶质浓度验证,较符合实际。结果表明,针对抽水井数量不足引起的拖尾问题,关键因素在于合理的井位布设与分阶段的抽水模式。在修复过程中,及时对地下水中污染物进行监测,并随着污染羽变化过程及时调整抽水方案,保证高浓度区一直有抽水井进行较大流量抽水,可有效提高修复效率并缩短修复周期。 相似文献
7.
抽水井附近由于流速过快往往发生非达西流,而远离抽水井随着流速下降又变为达西流.为了描述这些特征,建立了承压含水层中非完整井附近“非达西-达西”两区渗流模型,即距离抽水井较近的区域由于流速较快假设发生非达西渗流,并利用Izbash公式刻画,而距离抽水井较远由于流速较慢假设仍然满足达西定律,含水层中垂向流速较小也利用达西定律描述.通过线性化近似方法结合Laplace变换和有限Fourier余弦变换对模型进行了求解,分析探讨了该两区模型下水位降深曲线特征.结果表明:抽水初期,非达西渗流区域水位降深与全非达西渗流模型结果吻合,而抽水后期两区模型非达西渗流区域的水位降深与全达西模型水位降深基本一致,但大于全非达西渗流模型的水位降深;抽水初期,两区模型中达西渗流区域的水位降深比全达西渗流模型结果大,但比全非达西渗流模型结果小;对不同时间的水位降深随井距变化曲线分析发现非达西渗流区域水位降深随Izbash公式中的幂指数n增大而减小,而在达西渗流区域水位降深基本不受n值的影响.研究成果对非完整井抽水试验参数反演具有重要理论意义. 相似文献
8.
Allen P. Macfarlane Andrea Förster Daniel F. Merriam Jörg Schrötter John M. Healey 《Hydrogeology Journal》2002,10(6):662-673
Aquifer properties can be evaluated by monitoring artificially stimulated fluid movements between wells, if the fluid is
heated. Changes in the temperature profile recorded in observation wells indicate the flow path of the heated fluid, which
in effect acts as a tracer. A fluid-flow experiment in the Cretaceous Dakota Formation at the Hodgeman County site, west-central
Kansas, demonstrated the advantage of using the distributed optical-fiber temperature sensing method for monitoring transient
temperature conditions in this hydrological application. The fluid flow in the aquifer was increased by producing water from
a pumping well and injecting heated water in an injection well 13 m (43 ft) distant from the pumping well. The time-temperature
series data obtained and compared with results from previous pumping tests point to interwell heterogeneity of the aquifer
and to a zone in the sandstone aquifer of high hydraulic conductivity. However, the experiment would have allowed further
clarification of aquifer heterogeneity and thermal properties if at least one observation well had been present between the
injection and production wells.
Electronic Publication 相似文献
9.
利用地下水流数值模拟软件Modflow耦合大型抽水试验和长观孔水位两个模型的方法,对含水层参数进行了识别与校验,该方法求得的含水层参数避免了只利用抽水试验模型校验所带来的不确定性。同时利用抽水实验数据进行抽水与恢复的全过程曲线拟合,水位降深模拟相对误差小于6％,并且对均衡水量、泉水的溢出量以及末流场拟合程度进行了分析,均衡水量模拟相对误差最大为2．6％,泉水溢出量模拟相对误差最大为8．14％,末流场拟合程度也较好,从而提高了含水层参数的准确性。实例研究表明,这种求参方法精度高、切实可行,可以推广到其他的含水层参数确定中。 相似文献
10.
CHENChong-xi 《水文地质工程地质》2012,39(5):1-7
建立了地下水定流量抽水的稳定混合井流模型和不稳定混合井流模型,后者包括未抽水条件的混合水位（初始混合水位）模型和定流量混合抽水模型。得出若干基本规律。并与前人的相关问题做了对比,证明了Sokol D.,Hantush M.S.,Бочевер Ф.М. 和 Веригин Н.Н.及 Neuman关于混合观测孔水位建议方程所需要的条件以及MODFLOW软件关于混合抽水井各层流量的分配与各层的导水系数成正比建议所需要的条件。 相似文献
11.
为确定潜水含水层的渗透系数,施工了一个主抽水井和两个观测井,采用了潜水含水层稳定流完整井多孔、单孔抽水试验的公式法、非稳定流的完整井的半对数直线图解法和基于抽水试验资料处理软件的纽曼模型求参法三种方法进行计算,结果发现各计算方法的结果相差不大,能够相互验证。最后,选取半对数直线图解法的计算结果作为最终计算结果。该研究对潜水含水层渗透系数的计算有一定的参考价值。 相似文献
12.
Fatoumata Barry Duke Ophori Jeffrey Hoffman Robert Canace 《Environmental Geology》2009,56(8):1593-1603
Delineating capture zones of pumping wells is an important part of safe drinking water and well protection programs. Capture
zones or contributing areas of a groundwater extraction well are the parts of the aquifer recharge areas from which the wells
draw their water. Their extent and location depend on the hydrogeologic conditions such as groundwater recharge, pumping scenario
and the aquifer properties such as hydraulic conductivity, porosity, heterogeneity of the medium and hydraulic gradient. Different
methods of delineation can be used depending on the complexity of the hydrogeologic conditions. In this study, a 3-dimensional
transient numerical MODFLOW model was developed for the Central Passaic River Basin (CPRB), and used with a MODPATH particle
tracking code to determine 3-dimensional transient capture zones. Analytically calculated capture zones from previous studies
at the site were compared with the new numerically simulated capture zones. The study results revealed that the analytical
solution was more conservative, estimating larger capture zones than the numerical models. Of all the parameters that can
impact the size, shape and location of a capture zone, the hydraulic conductivity is one of the most critical. Capture zones
tend to be smaller in lower hydraulic conductivity areas. 相似文献
13.
抽水试验中,动水位数据采集记录及处理分析对水文地质参数计算具有重要意义。近年来自动水位计被广泛用于抽水试验,通过传感器压强水头变化值获取水位降深。因井管内水流动会产生水头损失,自动水位计安放位置不同会导致获取的井水位降深不同,不同于传统方法测得的井水面降深,对水文地质参数计算将产生一定影响,因此如何合理放置自动水位计以及在参数计算中如何应用其获取的水位降深都亟待开展试验研究。在黑河流域第四系大厚度含水层地区,选择典型单层试验孔和利用分层封隔技术实现的一孔同径多层抽水孔开展试验研究,在动水位以下抽水试验层段上部、中部、下部以及潜水泵上部和下部分别放置自动水位计进行了系统的数据采集分析。结果表明:抽水试验中因井管内水流沿程水头损失及速度水头差异导致不同位置自动水位计获得压强水头变化值不同,本次试验实测到井筒内不同部位井损值;井损值在潜水泵进水口处最大,随距潜水泵距离的增大而减小,为避开井筒内较大水头损失对参数计算的影响,自动水位计宜优选安放在潜水泵上部接近动水位位置;在单孔抽水试验中利用稳定流公式计算水文地质参数时,自动水位计获取水位降深含井损不可忽略,需通过多落程抽水试验数据分析扣除后使用。同时,抽水试验中自动水位计不同位置获取数据的处理分析方法为更好地理解井中水头损失提供了依据。 相似文献
14.
城区渗流场中地下阻水结构物众多,由于结构物的角点为奇异点,而且结构物的尺寸跟整个城区渗流场的尺寸相比非常小,这导致现有的计算方法难以对城区渗流场进行模拟分析。针对城区渗流场的这些特点,通过引进流体力学的复势、偶极子等理论,采用抽注水井对结构物进行模拟。通过控制井流量的大小,以形成强弱程度不同的阻水效果,而单元尺寸可以以井点间距为尺度,用较少的节点和单元即可对地下结构物进行处理,达到简化计算的目的。抽注水井法是一种简化的模拟算法,它忽略了结构物附近局部区域流场失真的情况,强调在宏观上与真实流场接近。 相似文献
15.
垃圾填埋场抽水试验及降水方案设计 总被引：2，自引：0，他引：2
垃圾填埋场中的渗滤液水位过高会引发一系列环境和稳定问题,工程上可用竖井抽水降低渗滤液水位。通过在填埋场现场进行抽水试验,确定垃圾土的渗透系数和抽水影响半径,在此基础上对填埋场降水的瞬态流问题进行有限元模拟,分析了抽水井口径和间距对填埋场降水的影响,提出了降水方案的设计步骤和方法。抽水试验表明,现场垃圾的渗透系数约为3.6×10-4cm/s,抽水影响半径约为20m。数值分析表明,井径的变化对于降水效果影响不大,而合理选择抽水井间距对降水十分关键。进行抽水方案设计时,应首先根据工期和降水幅度要求计算井间距,按井的出水速度选择水泵,再根据水泵确定井径,最后根据井径和过滤层形式确定钻孔尺寸并选择钻机。 相似文献
16.
Global curve-fitting for determining the hydrogeological parameters of leaky confined aquifers by transient flow pumping test 总被引：4，自引：1，他引：3
Proper management of groundwater resources requires an accurate evaluation of the parameters (hydraulic properties) that control the movement and storage of groundwater. Hydrogeological parameters are the basis of groundwater evaluation, modeling, and management and so on. A global curve-fitting method incorporating pumping test data and water table recovery data was introduced in the present study. The principal and procedures of the method were elucidated in detail. The drawdown and recovery data from two sets of transient flow pumping test conducted in no. 2 water source site of Shizuishan city were used to verify the calculation accuracy of the proposed method. The hydrogeological parameters were also estimated with traditional type curve-fitting method on the basis of formula derived by Hantush and Jacob. The hydrogeological parameters calculated by the two methods were compared and the results show that the parameters obtained by the global curve-fitting method are a little bigger than but very close to those obtained by the traditional type curve-fitting method. The proposed method which possesses three major advantages is feasible and reliable in aquifer parameter identification. A comparative study on various methods for parameter identification is required and expected in future study. 相似文献
17.
Breakthrough tailing has been observed during dye-tracing recovery tests in the Norville aquifer system (chalk), France. Karst-conduit flow and transport parameters were assessed using two different interpretative methods: the linear graphical method and the Chatwin method (implemented in the Qtracer2 program). The linear graphical method was used to model the observed tailing effects, which was explained by a second smaller delayed breakthrough curve. By comparing the results of tracer-test interpretation for the two methods, it was possible to relate the area of this second curve to the importance of turbulent flow in spring discharge. The more turbulent the flow, the less important the contribution of the second breakthrough curve and the tailing effect. The observed tailing could possibly be controlled by hydrodynamics to a greater extent than usually expected, the tailing effects being mostly attributed to diffusion phenomena. Tailing effects were expected to increase with discharge and the piezometric level, which would have resulted in overpressure in conduits, fissure flooding, etc. Instead, breakthrough tailing tended to disappear with increasing aquifer discharge, which would support the hypothesis of there being mostly hydrodynamic-controlled tailing effects instead of matrix- or fissure-diffusion.An erratum to this article can be found at 相似文献
18.
The flow rate to fully screened, partially penetrating wells in an unconfined aquifer is numerically simulated using MODFLOW 2000, taking into account the flow from the seepage face and decrease in saturated thickness of the aquifer towards the well. A simple three-step method is developed to find the top of the seepage face and hence the seepage-face length. The method is verified by comparing it with the results of previous predictive methods. The results show that the component of flow through the seepage face can supply a major portion of the total pumping rate. Variations in flow rate as a function of the penetration degree, elevation of the water level in the well and the distance to the far constant head boundary are investigated and expressed in terms of dimensionless curves and equations. These curves and equations can be used to design the degree of penetration for which the allowable steady pumping rate is attained for a given elevation of water level in the well. The designed degree of penetration or flow rate will assure the sustainability of the aquifer storage, and can be used as a management criterion for issuing drilling well permits by groundwater protection authorities. 相似文献
19.
Mohd Khairul Nizar Shamsuddin Saim Suratman Mohamad Pauzi Zakaria Ahmad Zaharin Aris Wan Nor Azmin Sulaiman 《Environmental Earth Sciences》2014,72(8):3129-3142
Induced bank infiltration (BI) is commonly implemented in other countries, but remains new and unexplored in Malaysia. Increasing river pollution could affect drinking water resources. Given the threat of pollution to raw water sources, applying induced BI to sustain water management is essential. This paper presents a case study of the BI method, which evaluates the effects of groundwater pumping and BI operation on the installation of wells as well as determines the effect of pumping rate on flow paths, travel time, the size of the pumping and capture zone delineation, and groundwater mixing in a pumping well in Jenderam Hilir, Malaysia. The proposed method performs infiltration safely and achieves the ideal pumping rate. Numerical modeling packages, MODFLOW and MODPATH (particle tracking) were used. Results indicate that the migration of river water into the aquifer is generally slow and depends on the pumping rate and distance from well to the river. Most water arrives at the well by the end of a pumping period of 1–5 days at 3,072 m3/day for test wells DW1 and DW2, and during simultaneous pumping for DW2 and PW1 for a well located 36 and 18 m, respectively, from the river. During the 9.7-day pumping period, 33 % of the water pumped from the DW1 well was river water, and 38 % from DW2 throughout 4.6 days was river water. The models provide necessary information for water operators in the design and construction of pumping and sampling schedules of BI practices. 相似文献
20.
流体激光测速的精度与示踪粒子的跟随特性即流体中异质粒子的非恒定运动特性密切相关。首先对粒子非恒定运动方程进行了探讨,着重考虑了在高颗粒雷诺数时该方程的修正问题,简要分析了该方程的数学属性,并构造了这类方程的数值计算方法。分析表明,高颗粒雷诺数下的粒子非恒定运动方程为非线性奇异积分方程,而当颗粒雷诺数小于1时,则线性化为第二类渥尔特拉(Volterra)积分方程。以几种均匀流中球形小颗粒的非恒定运动为算例,计算结果与其解析解及有关实验数据的比较表明,数值方法具有良好的计算精度。 相似文献