Interpretation Of Pumping Tests Research Articles

Obtaining the hydraulic and thermal properties of the main hydrostratigraphic units surrounding a standing column well using a thermal response test

In general, classical interpretation of pumping tests assume homogeneous hydraulic properties and cannot characterize aquifer heterogeneity in the form of a profile. In this work, a thermal response test, which is routinely performed prior to the design of ground source heat pump systems, is conducted on an open-walled borehole to identify the hydraulic conductivity profile and thermal properties of the main geological units. Parameter identification and uncertainty quantification are performed in a Bayesian framework and rely on a neural network and a spectral method to speed up the solution of the direct problem. The analysis of a data set from field testing showed that the use of temperature measurements alone provided a hydraulic conductivity profile, with an average value close to that provided by a conventional pumping test. For the specific conditions observed on the field, it was also possible to precisely identify the thermal properties, as was the case for the main geologic unit, but not for the thin geologic units whose distributions were similar to the priors used for inference. This indicates that in some geologic settings, a thermal response test could fail to provide the thermal properties of some units. The approach, however, paves the way for new characterization techniques.

Characterization of the productivity of basement aquifers at Bagoué region (North of Côte d’Ivoire)

This study aims to characterize the productivity of basement aquifers based on a database built by pumping test and drilling report from eighteen boreholes exploited in Bagoue region of Cote d’Ivoire. By using last version of a tool to assist in pumping test interpretation suggested by the French Mining and Geological Survey, Transmissivity parameter values of confined aquifers were determined through the well-known Theis method. In the same approach, critical yield value of borehole was determined at the equivalence point of linear and quadratic pressure drop from short-term pumping test data. Geostatistical analysis and kriging of transmissivity of aquifers were realized. Then, it was elaborated few predictive equations between hydrodynamic and hydraulic parameters based on their relationship level. Comparison of aquifers productivity and boreholes hydraulic capacity ended the methodology. Transmissivity ranged from 9.10-7 to 4.10-5 m2.h-1 while specific yield of boreholes reached between 0.34 and 23.07 m3.h-1. Yields from exploited boreholes varied between 0.5 m3.h-1 and 12 m3.h-1 with an average reaching 3.44 m3.h-1. Critical yield varied between 2.11 and 18.8 m3.h-1 with an average of 6.95 m3.h-1. According to geostatistical analysis of Transmissivity, its spatial spreading adjusted spherical model with a range reaching 0.13 meters. Findings highlighted 44 % of aquifer areas characterized by low value of transmissivity with great value of exploited outflow. That suggests a short-term availability of drinking water for living communities. In the same way, 11.11 % of boreholes were established into aquifer areas characterized by great transmissivity and low outflow values that suggests a better supply environment with long-term groundwater availability.

An Efficient Approach for Automatic Complex Fractured Networks Parameter Inversion Based on Surrogate Model and Deep Reinforcement Learning

AbstractComplex fracture networks are commonly generated in subsurface reservoirs, and the first and primary task is to understand their transport characteristics and properties. Like pumping test interpretation, the well‐testing interpretation is an effective means for transport characteristics analysis and parameter estimations, this work attempts to propose a parameter inversion approach for complex fracture networks based on well‐testing interpretation. Given that non‐unique solutions and computational inefficiencies are obstacles to practical interpretation, especially when complex fractures are existing, a new deep reinforcement learning (DRL) based approach is proposed for automatic curve matching on complex fractured networks well‐testing interpretation. Based on twin delayed deep deterministic policy gradient (TD3) algorithm, the proposed DRL approach is successfully applied to automatic matching of complex fractured networks' well test curves. In addition, to improve the training efficiency, a surrogate model of the well test model based on bidirectional GRU (Bi‐GRU) neural network was established. After episodic training, the agent finally converged to an optimal curve matching policy through interaction with the surrogate model. The results show that the average relative error of the curve's parameter interpretation is 4.34%. Additionally, the results from the case studies show that the proposed DRL approach has a high calculation speed.

Approximate solutions for flows in unconfined double porosity aquifers

Although flow in unconfined double porosity aquifers occurs in most part of the world such as in karst and crystalline aquifers, their hydrodynamic behavior is still poorly understood. Especially, analytical or semi-analytical solutions for flow in unconfined double porosity (DP) aquifers are scarce. In this paper analytical solutions are proposed for two configurations involving groundwater discharge to a stream adjacent to an unconfined aquifer, and flow induced by pumping with constant extraction rate, respectively. The analytical solutions are obtained based on an h2-linearization technique of the full mathematical model and using a Laplace transform. The above technique has not been used before to investigate the behavior in DP aquifers. The newly developed analytical solution is in agreement with numerical solutions of the full mathematical model, for small to moderate drawdowns which are as high as 25% of the initial water table (case of the well pumping problem). This confirms on one side the correctness of the analytical solution and on the other side the reliability of the developed h2-linearization technique. On the contrary the conventional confined aquifer equations approach can be used only if the drawdown does not exceed 5% of the initial head values. As potential application examples, the estimation of the flow-rate from an aquifer to an adjacent water body, and the interpretation of pumping tests in unconfined double porosity aquifers, allowing to estimate the values of the models parameters, are proposed.

Review of Petroleum and Hydrogeology Equations for Characterizing the Pressure Front Diffusion during Pumping Tests

In hydrogeology, the pressure front diffusion equation is crucial for the interpretation of pumping tests. It describes the displacement around the pumping well of the pressure front generated by a hydraulic disturbance, such as pumping or injection. This equation serves to physically locate the hydraulic objects (the recharge boundary, impermeable boundary, fault and hydraulic connection) that are able to influence the hydrodynamic behaviour of aquifers during a transient hydraulic test. However, several authors who have attempted to characterize this equation have come up with different expressions because the pressure front has been defined according to different approaches. This paper first clarifies the origin of the divergence between authors before reviewing seven approaches used to characterize the diffusion equation. In addition, a new approach is proposed, which is more practical and which defines the pressure front using the logarithmic derivative of the drawdown. Finally, all these reviewed approaches, plus the new one, are unified into a single general approach that defines the pressure front according to a general criterion, which is the critical drawdown, noted as sc. To do this, the pressure front criteria of each existing approach, including the new one, were converted into equivalent critical drawdowns. The ultimate goal of this study is to enable hydrogeologists to use all these approaches correctly in order to improve the accuracy of the interpretation of pumping test data for the better characterization of the geometry of aquifers.

Review: “Jacob’s Zoo”—how using Jacob’s method for aquifer testing leads to more intuitive understanding of aquifer characteristics

The interpretation of aquifer responses to pumping tests is an important tool for assessing aquifer geometry and properties, which are critical in the assessment of water resources or in environmental remediation. However, the responses of aquifers, measured by time-drawdown relationships in monitoring wells, are nonunique solutions that are affected by many factors. Jacob’s Zoo is a collection of graphical interpretations that allows students and practitioners to develop an intuitive feel for how natural hydrogeological systems work, and develop a set of skills that provide a better understanding of aquifer properties far beyond interpretation of pumping tests. Jacob’s Zoo, based on the work of Jacob (1950), fosters a deeper understanding, although few practitioners realize the full utility of the method. Jacob CE (1950) Flow of groundwater, In: Rouse H (ed) Engineering Hydraulics, Wiley, New York. P 321–386.

Use of microgravity for identification of delayed gravity drainage and conceptual model selection in unconfined aquifers

The estimation of hydraulic parameters at the aquifer scale typically relies in the analysis of pumping tests. Drawdown data, from a frequently limited number of boreholes and piezometers, is used in conjunction with analytical formulas derived for conceptually simplified models in a history matching procedure. In unconfined aquifers it is well known that the drainage process is controlled by the unsaturated zone. Several models have been proposed in the literature for the calculation of drawdown caused by pumping. Approaches range from the assumption of instantaneous and complete drainage to the inclusion of a delay term or the full implementation of the unsaturated zone to represent the delayed drainage in the unsaturated zone. Because borehole drawdown data is not informative about the unsaturated zone processes, it is common for practitioners to rely in the simplest models available, usually in some pumping test interpretation software. For example, Neuman’s instantaneous drainage model is still widely used in the industry even when it has been demonstrated that under some circumstances provides incorrect estimations of key aquifer parameters. Additionally, as boreholes are scarce, spatial information is ignored and conceptual assumptions of axial-symmetry are a normal practice. In this work we show how the use of microgravity instruments, sensitive to storage variations in the near subsurface, could be a simple, cheap and convenient tool for the identification of delayed drainage processes in unconfined aquifers. The joint use of drawdown and gravity data can be utilized to select the most preferable conceptual model for the parameter estimation problem.

Using water level and temperature time series to improve hydrogeological parameterization in a complex alluvial system

A new pumping station was designed in the northern high plain of the province of Padua (Veneto region, north-eastern Italy), aiming to reach an overall abstraction rate of about 2 m3/s, in order to relevantly contribute to the regional drinking water supply. Local unconfined aquifer is a highly permeable alluvial system, hydraulically connected to the Brenta river, one of the most important groundwater recharging sources of the entire hydrogeological basin, and the Camazzole lake, a former open-pit mine. This lake deepens below the water table and is directly connected to the surrounding phreatic aquifer and indirectly to the river, forming a 3-element hydraulic equilibrium. In order to evaluate the sustainability of the groundwater exploitation, this case study required an in-depth analysis of the hydrogeological resource, focusing on the estimation of hydraulic conductivity values and distribution. A numerical simulation was needed since the first step of the study, to plan the following field activities and provide a rough representation of the expectable drawdown in the pumped aquifer, even if the initial model had a very high level of uncertainty. Before the pumping tests no experimental data were available, so a homogeneous distribution of hydraulic conductivity was preliminarily assigned to the entire mesh, referring to a single bibliographic value available for the aquifer. After the analytical interpretation of pumping tests, different punctual values of hydraulic conductivity were estimated, but the parameter field was still very difficult to define, due to the complexity of the hydrogeological context and the non-uniqueness of the possible spatial interpolations. The availability of groundwater level observations at a larger scale allowed to calculate a set of hydraulic conductivity fields through the pilot points method, integrating the pumping tests results and extending aquifer characterization to a wider domain. The numerical model was finally calibrated with groundwater temperature monitored trends, reproducing the interaction between the lake and the phreatic aquifer through a heat transport simulation. The resulting hydraulic conductivity distribution has been considerably refined, especially at the interface between the lake and the aquifer, and the parameterization has been further validated using heat as a groundwater tracer.

Análise do rebaixamento da derivada logarítmica para interpretação de teste de bombeamento de taxa constante em aquíferos de substrato inclinado

Constant-rate pumping tests (CRPT) performed in aquifers having an inclined substratum (IS) cannot be interpreted using Theis-like models, due to an increasing thickness that is beyond conventional hydraulic assumptions. Using an empirical process based on numerical modelling, this study submits original tools for the detection of IS aquifers and the interpretation of their hydrodynamic responses to CRPT, using derivative [ds/dlog(t)] and flow dimension (n) analyses. It is shown that IS aquifers produce a drawdown log-derivative signal composed of two radial regimes and one spherical flow regime (n-sequence = 2–2–3). Comprehensive sensitivity analyses make it possible to constrain relationships between, on one hand, characteristic derivative responses, and on the other hand, hydraulic conditions such as pumping rate, distance from the well to the corner, substratum inclination, and aquifer properties, including anisotropic hydraulic conductivity. This study contributes to widening the array of tools available for the interpretation of pumping tests, by implementing a novel conceptual model for a specific type of nonuniform aquifer that has remained unaddressed; further, it provides another interpretation of the spherical flow regime, which has been interpreted in the petroleum literature to reflect partially penetrating/completing wells. Finally, a field application of the submitted interpretative tools to a CRPT into an IS aquifer is presented.

Bayesian estimation of the transmissivity spatial structure from pumping test data

Estimating the statistical parameters (mean, variance, and integral scale) that define the spatial structure of the transmissivity or hydraulic conductivity fields is a fundamental step for the accurate prediction of subsurface flow and contaminant transport. In practice, the determination of the spatial structure is a challenge because of spatial heterogeneity and data scarcity. In this paper, we describe a novel approach that uses time drawdown data from multiple pumping tests to determine the transmissivity statistical spatial structure. The method builds on the pumping test interpretation procedure of Copty et al. (2011) (Continuous Derivation method, CD), which uses the time-drawdown data and its time derivative to estimate apparent transmissivity values as a function of radial distance from the pumping well. A Bayesian approach is then used to infer the statistical parameters of the transmissivity field by combining prior information about the parameters and the likelihood function expressed in terms of radially-dependent apparent transmissivities determined from pumping tests. A major advantage of the proposed Bayesian approach is that the likelihood function is readily determined from randomly generated multiple realizations of the transmissivity field, without the need to solve the groundwater flow equation. Applying the method to synthetically-generated pumping test data, we demonstrate that, through a relatively simple procedure, information on the spatial structure of the transmissivity may be inferred from pumping tests data. It is also shown that the prior parameter distribution has a significant influence on the estimation procedure, given the non-uniqueness of the estimation procedure. Results also indicate that the reliability of the estimated transmissivity statistical parameters increases with the number of available pumping tests.

Assessment of the value of microgravity to estimate the principal directions of the anisotropic transmissivity of aquifers from pumping tests: A study using a Hough transform based automatic algorithm

Estimation of the hydraulic parameters of an aquifer is usually performed via interpretation of pumping tests. This invasive method requires drilling both pumping and observation wells. As the process is expensive, only a single pumping well and one or two observation wells or piezometers are generally drilled, at most. The interpretation is done assuming aquifer isotropy and homogeneity. However, in many aquifers, horizontal anisotropy in hydraulic conductivity greatly affects the flow regime. Its disregard may lead to important misinterpretations, especially for environmental impact assessments. This paper studies the capabilities of gravity for the identification and determination of the principal directions of anisotropy. This has been automatized using a methodology based on the Hough Transform. The results show how a microgravity survey could be an adequate and relatively cheap monitoring tool for the identification of anisotropy. This is valuable information that can be used in the decision making process for performing or discarding additional studies. Even more, the presented methodology can be extended to other studies in which contour maps are used to identify directionality in any process or property.

Recursos hídricos subterrâneos da região de Parnamirim, RN: uso das águas e potencialidades

A área de estudo está inserida na Bacia do Rio Pirangi, RN, ocupando superfície de 370 km², onde situa-se a cidade de Parnamirim. A expansão urbana no município de Parnamirim dá-se de forma acelerada e sem uma estrutura adequada, notadamente pela ausência de rede esgotos, com riscos de contaminação das águas subterrâneas, que constituem a principal fonte de suprimento hídrico das demandas urbanas e rurais. O presente estudo foi elaborado com o objetivo de quantificar o uso e avaliar as potencialidades das águas subterrâneas, considerando-se a necessidade do aumento da oferta de água de boa qualidade e menores riscos de serem afetadas por atividades antrópicas. Foi realizado um cadastro atualizado de poços e a caracterização do arcabouço hidrogeológico, seguido da avaliação dos parâmetros hidráulicos do aquífero e do comportamento do fluxo subterrâneo. A espessura saturada do Sistema Aquífero Barreiras aumenta de oeste para leste, variando de 15,47 a 56,5 m (com média de 32,45 m). Os parâmetros hidrodinâmicos foram estimados a partir da interpretação de ensaios de bombeamento, que forneceu transmissividade média de 5,9x10-3 m²/s, condutividade hidráulica média de 2,82x10-4 m/s e porosidade efetiva média de 15%. O sentido do fluxo subterrâneo é em geral de oeste para leste, sendo possível identificar as correspondentes zonas de recarga e de descarga das águas subterrâneas. A Recarga foi estimada em 253 mm/ano, que corresponde à uma taxa de infiltração de 16,4% da precipitação

An integrated GIS-based tool for aquifer test analysis

The quantification of the hydraulic parameters is important to support decision making in environmental impact assessment, water resources evaluation or groundwater contamination remediation, among others. These kind of parameters derived from aquifer tests usually encompasses a vast amount of data (spatial and non-spatial) for management and analysis. To achieve this in a clear and understandable manner, the GIS environment is a useful instrument. Development of innovative software to analyze pumping tests in a GIS platform environment to support the hydraulic parameterization of groundwater flow and transport models is presented in this paper. This new platform provides three interconnected modules to improve (a) pumping test interpretation code through a user-friendly interface, (b) pumping test data visualization supported by a set of tools that perform spatiotemporal queries in a GIS environment and (c) the storage and management of hydrogeological information. Additionally, within the GIS platform, it is possible to process the hydraulic parameters obtained from the pumping test and to create spatial distribution maps, perform geostatistical analysis and export the information to an external software platform. Finally, a real-world application in the area of Barcelona (Spain) has shown the usefulness of the tools developed in support of hydrogeological analysis.

Estimating transmissivity from single‐well pumping tests in heterogeneous aquifers

AbstractAlthough aquifers are naturally heterogeneous, the interpretation of pumping tests is commonly performed under the assumption of aquifer homogeneity. This yields interpreted hydraulic parameters averaged over a domain of uncertain extent which disguises their relation to the underlying heterogeneity. In this study, we numerically investigate the sensitivity of the transient drawdown at the pumping well, to nonuniform distributions of transmissivity in confined aquifers. Frechet kernels and their time derivative are used to estimate two spatially averaged transmissivities, denoted the equivalent and interpreted transmissivity, Teq and Tin, respectively, for the case of single‐well pumping tests. Interrelating Teq and Tin is achieved by modeling Tin in terms of a distance dependent, radially heterogeneous field. In weakly heterogeneous aquifers, Teq approximates TPW, the local transmissivity at the pumped well. With increasing degree of heterogeneity, Teq deviates from TPW as pumping propagates. Tin starts at TPW, approaching the spatial geometric mean of transmissivity during late pumping times. Limits of the proposed spatial weighting functions are investigated by treating the interpreted storativity, Sest, as an indicator for flow connectivity. It is shown numerically that the spatial weights for Teq and Tin agree well to the underlying heterogeneity if . Finally, implications for applying the concepts of Teq and Tin to heterogeneous domains, and, for real world applications are discussed. It is found that time‐dependent spatial averages of Tin agree well with estimates of the interpreted transmissivity from the Continuous‐Derivation method.

Evaluation of Analytical Methods to Study Aquifer Properties with Pumping Tests in Coastal Aquifers with Numerical Modelling (Motril-Salobreña Aquifer)

Two pumping tests were performed in the unconfined Motril-Salobrena detrital aquifer in a 250 m-deep well 300 m from the coastline containing both freshwater and saltwater. It is an artesian well as it is in the discharge zone of this coastal aquifer. The two observation wells where the drawdowns are measured record the influence of tidal fluctuations, and the well lithological columns reveal high vertical heterogeneity in the aquifer. The Theis and Cooper-Jacob approaches give average transmissivity (T) and storage coefficient (S) values of 1460 m2/d and 0.027, respectively. Other analytical solutions, modified to be more accurate in the boundary conditions found in coastal aquifers, provide similar T values to those found with the Theis and Cooper-Jacob methods, but give very different S values or could not estimate them. Numerical modelling in a synthetic model was applied to analyse the sensitivity of the Theis and Cooper-Jacob approaches to the usual boundary conditions in coastal aquifers. The T and S values calculated from the numerical modelling drawdowns indicate that the regional flow, variable pumping flows, and tidal effect produce an error of under 10 % compared to results obtained with classic methods. Fluids of different density (freshwater and saltwater) cause an error of 20 % in estimating T and of over 100 % in calculating S. The factor most affecting T and S results in the pumping test interpretation is vertical heterogeneity in sediments, which can produce errors of over 100 % in both parameters.

Assessment of groundwater flow in volcanic faulted areas. A study case in Queretaro, Mexico

This work integrates local stratigraphy and faults to constraint a numerical model of groundwater flow in the North area of the Valley of Queretaro aquifer. Basic geological information was established from the reinterpretation of well logs, 40Ar*/39Ar dating of rocks, and field mapping. In particular, dating allowed to obtain the timing of emplacement of a magmatic dyke inferred to be emplaced along the El Nabo fault. The increase of flow rate and temperature in the El Nabo well suggest that the fault and dike transport a regional flow. A numerical model was implemented to evaluate the contributions of faulting and volcanic structures in the overall groundwater flow. The model, accomplished with the Visual-Modflow software and Modflow 2000 code, was partially constrained by the results of a pumping test in the El Nabo well, the deepest well (Lat. 20°42’14”N, Long. 100°28’45”W, ca. 1000 m depth) located in the Queretaro area. The interpretation of the model results and field observations suggest that faults collect the regional flow, compartmentalize the reservoir, and are responsible of the dramatic increase of flow rate from 6 to 47 l/s when drilling the El Nabo well below a depth of 850 m. The study presented here allowed the assessment of normal faults and intrusives determining groundwater flow and might be relevant to the knowledge of flow dynamics in nearby volcanic valleys. The analysis of the pumping test suggest the presence of two different groundwater flow systems: (1) a flow related with the limestone and shale unit and (2) a regional linear flow through faults. The implemented numerical model, based on geological information, allowed a better understanding of complex aquifer systems that cannot be evaluated by analytical methods. Moreover it can be a useful application for a better interpretation of pumping tests and to add complementary data of other pumping tests and/or hydrogeochemical analysis.

Groundwater potential of the Egbe-Mopa basement area, central Nigeria

An investigation on the groundwater potentials of the Egbe-Mopa area in central Nigeria, underlain by the Basement Complex, is presented. The investigation involved mapping of the subsurface by use of vertical electrical soundings; measurement of depth to groundwater; and evaluation of hydraulic conductivity, transmissivity and yield by means of pumping test interpretation. The results indicate subsurface units that range from three to five resistivity layers; depth to groundwater of 0–10 m; overburden thickness of 3–16 m; hydraulic conductivity of 6.2 × 10−6 to 3.4 × 10−4 m/s; transmissivity of 4.3 × 10−7 to 2 × 10−3 m2/s; and groundwater yield of 0.2–2.5 L/s. The hydraulic head assessments revealed a general northward groundwater flow direction. The study identified three aquifer potential types, of high, medium and low productivity, respectively. Based on the longitudinal conductance of the overburden units, four distinct Aquifer Protective Capacity zones were delineated, namely, poor, weak, moderate and good. Citation Okogbue, C.O. and Omonona, O.V., 2013. Groundwater potential of Egbe-Mopa basement area, central Nigeria. Hydrological Sciences Journal, 58 (4), 826–840.

Improved predictions of saturated and unsaturated zone drawdowns in a heterogeneous unconfined aquifer via transient hydraulic tomography: Laboratory sandbox experiments

► Uniform parameters lead to biased drawdown predictions in the (un)saturated zones. ► Accounting for aquifer heterogeneity yields significant improvements in predictions. ► Considering unsaturated zone (UZ) heterogeneity produced a minor improvement. ► UZ heterogeneity plays a minor role in forming the S shape drawdown curve. ► Hydraulic tomography can be used to characterize unconfined aquifers. Interpretation of pumping tests in unconfined aquifers has largely been based on analytical solutions that disregard aquifer heterogeneity. In this study, we investigate whether the prediction of drawdown responses in a heterogeneous unconfined aquifer and the unsaturated zone above it with a variably saturated groundwater flow model can be improved by including information on hydraulic conductivity ( K ) and specific storage ( S s ) from transient hydraulic tomography (THT). We also investigate whether these predictions are affected by the use of unsaturated flow parameters estimated through laboratory hanging column experiments or calibration of in situ drainage curves. To investigate these issues, we designed and conducted laboratory sandbox experiments to characterize the saturated and unsaturated properties of a heterogeneous unconfined aquifer. Specifically, we conducted pumping tests under fully saturated conditions and interpreted the drawdown responses by treating the medium to be either homogeneous or heterogeneous. We then conducted another pumping test and allowed the water table to drop, similar to a pumping test in an unconfined aquifer. Simulations conducted using a variably saturated flow model revealed: (1) homogeneous parameters in the saturated and unsaturated zones have a difficult time predicting the responses of the heterogeneous unconfined aquifer; (2) heterogeneous saturated hydraulic parameter distributions obtained via THT yielded significantly improved drawdown predictions in the saturated zone of the unconfined aquifer; and (3) considering heterogeneity of unsaturated zone parameters produced a minor improvement in predictions in the unsaturated zone, but not the saturated zone. These results seem to support the finding by Mao et al. (2011) that spatial variability in the unsaturated zone plays a minor role in the formation of the S-shape drawdown-time curve observed during pumping in an unconfined aquifer.

Modeling the effect of clay drapes on pumping test response in a cross-bedded aquifer using multiple-point geostatistics

Summary This study investigates whether fine-scale clay drapes can cause an anisotropic pumping test response at a much larger scale. A pumping test was performed in a sandbar deposit consisting of cross-bedded units composed of materials with different grain sizes and hydraulic conductivities. The measured drawdown values in the different observation wells reveal an anisotropic or elliptically-shaped pumping cone. The major axis of the pumping ellipse is parallel with the strike of cm to m-scale clay drapes that are observed in several outcrops. To determine (1) whether this large-scale anisotropy can be the result of fine-scale clay drapes and (2) whether application of multiple-point geostatistics can improve interpretation of pumping tests, this pumping test is analyzed with a local 3D groundwater model in which fine-scale sedimentary heterogeneity is modelled using multiple-point geostatistics. To reduce CPU and RAM demand of the multiple-point geostatistical simulation step, edge properties indicating the presence of irregularly-shaped surfaces are directly simulated. Results show that the anisotropic pumping cone can be attributed to the presence of the clay drapes. Incorporating fine-scale clay drapes results in a better fit between observed and calculated drawdowns. These results thus show that fine-scale clay drapes can cause an anisotropic pumping test response at a much larger scale and that the combined approach of multiple-point geostatistics and cell edge properties is an efficient method for integrating fine-scale features in larger scale models.

Groundwater resources assessment for irrigable agricultural lands in the Wadi Araba area, southern Jordan

The main target of this research paper was to the hydrogeological assessment of the groundwater resources to irrigate 600 ha of irrigable agricultural lands, distributed along the Dead Sea–Aqaba Highway in Umm, Methla, Wadi Musa, Qa’ Saideen and Rahma, southern Jordan. Therefore, a comprehensive groundwater study was commenced by drilling eight new wells which can be used to supply irrigable areas with the existing groundwater that would be enriched by the yield of three proposed recharge dams on Wadi Musa, Wadi Abu-Burqa, and Wadi Rahma. The evaluation of the pumping test data of the drilled was carried out using the standard methods of pumping test interpretation. This was based on the available water table measurements at well locations and knowledge of water flow in the general. The sustainable yield of each well was calculated based on the pumping test parameters. The obtained results indicate that pumping out of Beer Mathkor wells should not exceed 1,100 m3/day in the case of continuous pumping and 8,700 m3/day in the case of intermittent pumping. Since the water table did not significantly change with small changes in pumping (it took eightfolds of magnitude increase in pumping from approximately 1,100 to 8,700 m3/day to show a significant drop in the water table equivalent to about 5.5 MCM per year from the aquifer.