Pumping Test Method Research Articles

Predicting heavy metal transport in groundwater around Lemna dumpsite: implications for residence utilizing borehole water in Cross River State, Nigeria

Groundwater is considered the most important natural resource to mankind. Groundwater constitutes an important part of the hydrological cycle and is more prone to pollution. Dumpsite located in close proximity to groundwater resources is highly susceptible to leachates pollution. Predicting the susceptibility of groundwater pollution is crucial to address industry-standard codes for groundwater flow, contaminant transport, local to regional-scale water quality, and source water protection issues. Therefore, predicting heavy metal transport in groundwater around Lemna dumpsite in Cross River State, Nigeria, was examined. Soil samples were purposively collected with a soil Auger, along a straight line at (5 m, 25 m and 50 m) in the dumpsite. Water samples were purposively collected from five (5) boreholes close to Lemna dumpsite. The study utilized pumping test method to obtain data for the analysis of heavy metal transport in groundwater. Data analysis of the laboratory results of soil and borehole water quality focuses on arsenic, lead, cadmium, chromium, nickel, and mercury. Paired sample t test was used to analyse the soil and borehole water quality. Visual Modflow was also used to analyse the solute transport of heavy metals in groundwater around Lemna dumpsite. The paired sample t test of the analysis of heavy metals in soil exhibited a significant difference (p < 0.05) compared to National Environmental Standard Regulation and Enforcement Agency limits. The paired sample t test of the analysis of heavy metals in borehole water exhibited a significant difference (p < 0.05) compared to World Health Organization limits. The significant level indicates contamination of the soil and borehole water. The findings revealed a spatial spread of 259.2000 m2/day, with the contaminant travelling up to 94,608 m2/year. The extent of heavy metals concentration exhibited a maximum of 0.991 mg/l to a minimum of (− 6.72 × 10–18 mg/l), with concentrations decreasing as the plume extend. The study recommends the need for remediation and stringent monitoring to mitigate heavy metal contamination of boreholes near Lemna dumpsite.

An improved technology for monitoring groundwater flow velocity and direction in fractured rock system based on colloidal particles motion.

The colloidal borescope, using colloidal particle motion, is used to monitor the flow velocities and directions of groundwater. It integrates advanced techniques such as microscopy, high-speed photography, and big data computing and enjoys high sensitivity at the micron level. However, In the same well, the groundwater flow velocity monitored by colloidal hole mirror is varies greatly from that obtained by conventional hydrogeological monitoring, such as pumping test. In order to solve this problem, the stability catcher and stratified packer are designed to control the interference of the vertical flow in drilling, and to monitor the flow velocity and direction of groundwater velocity at the target aquifer and target fracture. Five wells with different aquifers and different groundwater types were selected for monitoring in south-central China. The instantaneous velocity and direction are converted into east-west component and north-south component, the average velocity and direction is calculated according to the time of 10min, and the particle trajectory diagram is established. Based on these results, it proposed a concept of cumulative flow velocity. Using curve-fitting equations, the limits of cumulative flow velocities as the monitoring time tends to infinity were then calculated as the actual flow velocities of the groundwater. The permeability coefficient of aquifer is calculated by using the fissure ratio of aquifer, hydraulic slope and flow velocity, and compared with the permeability coefficient obtained by pumping test. The results are as follows: (1) The variation coefficient of the instantaneous flow velocity measured at the same depth in the same well at different times is greater than that of the time average flow velocity and greater than that of the cumulative flow velocity. The variation coefficient of the actual velocity is the smallest, indicating that the risk of using the actual flow velocity is lower. (2) The variation coefficient of the flow rate monitored at different depths in the same well is mainly controlled by the properties of the aquifer. The more uniform water storage space in the aquifer, the smaller the variation coefficient. (3) The comparison between the permeability coefficient obtained by monitoring and the permeability coefficient obtained by pumping test shows that the flow of structural fissure water controlled by planar fissure is more surface flow, and the results are consistent. When the groundwater flow is controlled by pores and solution gaps, the flow channel is complicated, which is easy to produce turbulent flow, and the result consistency is poor. (4) According to different research accuracy requirements, different monitoring and calculation methods can be selected for different aquifers and groundwater types. Researches show that, the permeability coefficient calculated for the actual flow velocity in well DR01 is the same as that calculated for the pumping test. The aquifer characteristics reflected by the coefficient of variation of the actual flow velocity in the same aquifer are more realistic. The pumping test method obtains the comprehensive parameters of a certain aquifer, and this method can be used to monitor a certain fissure. In this paper, the new technology developed for monitoring, and the new algorithm established for data processing, can accurately obtain the flow velocity and direction of groundwater, using capsule hole mirror monitoring method. The key parameters of hydrogeology can be obtained by using one well, which can reduce the time and cost input and improve the work efficiency.

Determination of aquifer hydraulic parameters and groundwater protective capacity in parts of Nsukwa clan, Nigeria.

The goal of this study is to determine aquifer parameters and groundwater protective capacity in parts of the Nsukwa clan using geoelectric and pumping test methods. Seventeen vertical electrical soundings were acquired to determine the geoelectric properties, while two wells were drilled to determine the lithology and the aquifer parameters of the area. The result showed that the lithology comprised lateritic topsoil and sand, fine sand, medium sand, and coarse sand, respectively. Geoelectric data interpretation using Win Resist software revealed a close correlation with the well record. Geoelectric data analysis indicated that prolific aquifer can be sourced within the third and fourth layers, located within 24.2-43.8m and comprised medium to coarse sand. The aquifer resistivity ranged from 703.1 to 26,367.7Ωm. The Dar Zarrouk parameters, such as transverse resistance (R) and longitudinal conductance (S), were applied to determine the aquifer transmissivity (T) and hydraulic conductivity (K). The computed T and K from geoelectric sounding ranged from 11.37 to 34.79m2/day, with a mean value of 18.51m2/day and 0.8243m/day, respectively, while the T and K values from the pumping test are 18.58m2/day and 0.8251m/day, respectively. S and R values ranged from 0.001179 to 0.0131619Ω-1 and 2434 to 102,090Ωm2, respectively, revealing a poor aquifer protective capacity and moderate yield. The storativity and storage coefficient of the aquifer values of 0.0023 and 0.072m2/min, respectively, revealed a confined aquifer capable of providing sufficient water to the people. These findings showed moderate aquifer potential with poor protective capacity; thus, adequate aquifer protective strategies are recommended.

Investigating the Representative of Aquifer Transmissivity Determined by Passive Response Methods: A Comparison With Time‐Dependent Hydraulic Parameters Inferred From Different Stages of Pumping Tests

AbstractAquifer pumping tests represent a standard method for estimating hydraulic characteristics, with practitioners often focusing on late period drawdown data because these are less affected by within‐ and near‐borehole effects (e.g., borehole‐storage and skin effects). Alternatively, groundwater responses to natural forcing (e.g., barometric pressure and earth tides) provide a passive method for estimating aquifer parameters at a low cost. However, to the best of our knowledge, no studies have compared parameters calculated from different periods within a pumping test with those from passive methods. Herein, we compare the aquifer transmissivity estimated using both active and passive methods in two wells located in the Beetaloo Region of Northern Australia. The active method estimates aquifer transmissivity during three periods (i.e., the early, middle, and late periods) of an aquifer pumping test, while the passive method employs groundwater responses to barometric‐pressure and earth‐tide fluctuations. We find that the range of best‐fit aquifer transmissivity is 1.18 × 10−5–1.79 × 10−5 m2/s and 1.73 × 10−5–2.14 × 10−5 m2/s for OW1 and OW2, respectively. The transmissivity estimated from the barometric pressure response method is the largest. The aquifer transmissivity using barometric pressure responses are consistent with early‐ and middle‐period estimates. This suggests that barometric pressure responses are more sensitive to within‐ and near‐borehole effects. The scales of the tidal response method are smaller than those of the pumping test method.

Aquifer characterization using geophysical and pumping test data in Kericho, Kenya

The exploration of groundwater resources has considerable potential for boosting water supplies in Kericho County, Kenya. However, it is underused due to limited knowledge caused by lack of adequate research in this field. As a way to fill this gap, this study aimed to characterize hydraulic and hydrogeological parameters controlling groundwater occurrence in the Kericho aquifer in Kericho County, Kenya. To achieve this objective, the study utilized a combination of geophysical and pumping test data. Consequently, fifty Vertical Electric Soundings (VES) were carried out to determine the aquifer properties of the study area. Further, seven out of fifty surveyed sites were drilled to depths ranging between 30m and 230m, and test pumping was done for 24 hours. Geophysical results show that the average hydraulic conductivity in the study area varies from 1.96 m day-1 to 6.2 m day-1 . The transmissivity ranged from 35.83 m2 day-1 to 5166.4 m2 day-1 , while the yield ranged between 0.7 and 9.7 M3 /hr. The aquifer hydraulic parameters determined from geophysical and pumping test data were analysed using one-way analysis of variance (ANOVA). The results show no significant difference (p = 0.948151&gt; 0.05) on hydraulic conductivity between geophysical and pumping test methods. Therefore, this study confirmed the reliability of both methodologies for groundwater assessment. Identifying prospective groundwater zones in the research area demonstrates that the combination of these methods is efficient and suited for groundwater exploration. It is suggested that observation wells be added in future studies to allow for the computation of storativity.

Characteristics of Unconfined Aquifer Based on Pumping Test on Wells Made by residents in the Biromaru Area Sigi Regency

The Biromaru area, located in Sigi Regency, is an agricultural area that was once relies heavily on Gumbasa irrigation in the management of rice fields and farming businesses plant another. Aftermath of the earthquake on September 28, 2018 Gumbasa irrigation canal suffered such severe damage that it could no longer drain the rice fields in the Biromaru area. As a result, most of the people have a livelihood in farming in the fields seeks to carry out independent exploration and exploitation of groundwater. The purpose of this study is to determine the characteristics of unconfined aquifer which includes Transmissivity (T), Storativity (S) and Specific yield (Sy) in the research area. The data collection method used is the pumping test method, long term test and step drawdown test and the analytical method used is the curve-fitting method Neuman, Theis recovery and Hantush Bierschenk for well efficiency performance analysis. Based on the well test and aquifer test as well as lithological correlation results, the Transmissivity value is 315-600 m2/day, Storativity 2.15X10-2 - 6.17X10-3, Specific Yield 1.34X10-1-2.86X10-1, Hydraulic Conductivity 1.19X102-36.4 m/day. and permeability 16,488 m/day. The potential for groundwater discharge in the study area is 226.067 cm3/day. The maximum available discharge is 2.01 X 10-2 m3/s, the value of B = 4.76 X 10-3 and the value of C = 1.8 X 10-5. Aquifer Loss 90.1%, Well Loss 9.9% and Well Efficiency (Ew) 88.3%.

Assessment of the Nubian aquifer characteristics by combining geoelectrical and pumping test methods in the Omdurman area, Sudan

The recent research is carried out to model the characteristics and productivity of the groundwater aquifer in the Omdurman area, Sudan, by combining electrical resistivity and pumping test methods. Omdurman is the most populous city known as the traditional capital of Sudan. Vertical electrical sounding (VES) survey using Schlumberger array is carried out along four profiles to delineate the potential groundwater zones. Application of 1D geophysical inversion revealed five geoelectric layers, including recent deposits, clay, silicified and ferruginous sandstone, and sandstone. Additionally, based on the outcome of VES inversion, Dar Zarrouk parameters, including transverse resistance and longitudinal conductance, were calculated to model the aquifer characteristics. The transverse resistance ranged from 5587 to 309,853 Ωm2, while the longitudinal conductance varied between 0.14 and 2.5 Ω−1. The hydraulic conductivity and transmissivity are further measured using the VES data, ranging from 1.4 to 5.2 m/d and 435 to 1564 m2/day, respectively. The step-drawdown pumping tests were performed to evaluate the aquifer characteristics and thus validate the result of the geoelectrical method. The transmissivity obtained from the step test varied between 583 and 1226 m2/day, showing an acceptable agreement with those of geoelectrical data. Based on the measured parameters, the aquifer is classified as highly productive and ideal for groundwater development. The step drawdown test was further used to assess the performance of groundwater wells. The results indicated that faulty well design and inappropriate pumping rates influence some wells in the study area, resulting in high drawdown and low well efficiency. Overall, the objectives of the study were successfully achieved; nonetheless, detailed hydrogeological and geophysical investigations are recommended for comprehensive evaluation of the groundwater aquifer.

Determination of groundwater potential using electrical resistivity survey and borehole logging in sites I and III of Delta State University, Abraka Nigeria

This study examines the aquifer properties and lithological structure of Abraka, Nigeria, specifically the Delta State University Site I and III environs. Ten Schlumberger geoelectric soundings, geophysical well logging and pumping test method were employed using an ABEM Terrameter. A drilled water well and existing borehole data were used for this study. The result of the lithological study revealed that the subsurface formations consist of topsoil, lateritic sand, fine and medium grain sand mixed with clay. The topsoil is brownish with thickness of 2 m, the laterite is reddish with thickness of 4 m, the fine sand is whitish with thickness of 10 m, and the medium sand is also whitish with thickness &gt;12 m. The results of the evaluation of the geoelectric data using curve matching and Win Resist computer iteration was in strong agreement with that of the well record, with a subsurface that is composed of 4 to 6 geo-electric layers. The depth ranges from 13.5m to 97.8m while the resistivity ranges from 1021.2 Ωm to 9092.4 Ωm. A core soil sample collected at an interval of 5m, spontaneous potential and resistivity logs were carried out on the well. The hydraulic conductivity, well's transmissivity, storativity, and specific capacity are 102.7m2/day, 5.14 m/day, 0.00062 and 0.39 m3/m respectively. It is recommended that a drill depth of 30 m and above should be accessed for potable water in the area. From the result of this survey, we infer that this aquifer is confined and capable of supplying the people with adequate and good quality drinking water.

Estimating Hydraulic Conductivity, Transmissibility and Specific Yield of Aquifer in Barind Area, Bangladesh Using Pumping Test

Reliable hydraulic parameters values are essential and crucial basic data for potential groundwater withdrawal (aquifer yield) and also for sustainable groundwater management. They are also essential for simulation model study for different management scenario analyses. The laboratory test has limitations, while in situ tests produce representative aquifer parameters. The pumping test method is the only method that provides simultaneous information on the hydraulic behavior of the well, the aquifer, and the aquifer boundaries. Pumping tests were performed to determine aquifer hydraulic properties such as hydraulic conductivity (K), transmissibility (T), and specific yield (Sy) at two Upazilas of the Barind area, namely Nachol and Niamatpur. The aquifer formation is composed of layers: upper fine sand, medium sand, a conductive sand layer, and lower fine sand at the bottom, below which the impervious clay layer exists. The K was determined through Dupit’s steady radial flow equation, T through Theis’s and Copper-Jacob approach, and Sy through Copper-Jacob and gravity drainage of aquifer materials. The mean K, T, and Sy were found as 30.3 m3/m2/day, 756.7 m3/m/day, and 4.6%, respectively for the Nachol location; and 52.7 m3/m2/day, 1027.3 m3/m/day and 6.6%, respectively for Niamatpur location. The values obtained are supported by regional values reported earlier, and also by other locations’ values situated elsewhere having similar aquifer materials. To achieve long-term sustainability in the studied locations, withdrawal of groundwater resources should be optimized considering the aquifer hydraulic properties values.

Evaluation of Well Improvement and Water Quality Change before and after Air Surging in Bedrock Aquifers

When a drought occurs, drought response is mainly focused on the development of new wells. However, it is inefficient to respond to droughts by developing additional new wells in areas where many existing groundwater wells have been developed. Rather, it is necessary to find a way to use the existing wells efficiently and, if possible, increase the amount of groundwater that can be pumped. In this study, a pumping test and analysis method were used to evaluate the effect of air surging on improving existing wells. Drawdowns were reduced in the test wells, and, accordingly, the average specific discharges and transmissivities were increased. Since many factors in bedrock aquifers must be considered in order to calculate the well efficiency for the evaluation of the well performance, it seems better to compare the pumping rate and drawdown based on a reference time calculated by an adjusted time. Such factors could be the uncertainty of the aquifer model, aquifer inhomogeneity, and a hydrogeologic boundary. Additionally, in this process, the changes in groundwater quality were investigated, as well as the substances that caused the degradation of the well performance in bedrock aquifers. According to the results of the groundwater quality analysis conducted during the surging process and the step drawdown tests, there was no significant groundwater quality change before and after surging, but it appeared that there was an inflow of contaminants from the upper shallow strata close to the surface. According to the results of the XRD, XRF, and SEM-EDS analyses for the substances collected during surging and the substances deposited inside the well pipe, most of the substances were Fe-related amorphous components. Additionally, Fe coexisted with components such as As, V, and Zn, which formed the well casing together with Fe and were eluted in the surging process and step drawdown tests.

Assessment of Riverbed Clogging in Reservoirs by Analysis of Periodic Oscillation of Reservoir Level and Groundwater Level

In the area of the the Krško alluvial field, the Brežice hydroelectric power plant (BHPP), with its surface water reservoir, was completed in 2017. The new BHPP reservoir dam is located approximately 7 km air distance downstream of the old Krško nuclear power plant (NEK) reservoir dam. The NEK dam was built in the 1970s. The primary purpose of the NEK reservoir is to provide fresh water for cooling the NEK nuclear reactor. To assess the impact of the newly built surface water reservoir on groundwater, we performed a series of data analyses prior to its construction. One part of the analysis relating to data from the monitoring facility of the NEK showed an interesting correspondence between the water level oscillation in the NEK reservoir and the groundwater oscillation in the nearby observation well. Based on measurements taken in 2000, we sought to estimate the clogging of the Sava riverbed sediments in the area of the old NEK surface water reservoir. To determine the permeability of the riverbed sediments, we applied geometry similar to that chosen by Hantush for his pumping test method. Using Fourier analysis, we determined the dominant frequencies from the hydrograph records of the NEK surface water reservoir and from the pressure probe in the nearby observation well. Based on the determination of the dominant frequency, we used the wave equation to compare the influence of different values of the hydraulic transmissivity of the clogged part of the NEK surface water reservoir on the transfer of its water oscillations to the groundwater in the observation well. For the hydraulic values of the non-clogged part of the aquifer (T, S), we assumed the values from the pumping experiments performed in the alluvial aquifer of Krško polje. We also assumed that the aquifer is homogeneous and isotropic, as Hantush had assumed in his method for the determination of semipervious river beds. The results obtained indicated the potential for estimation of the thickness of the clogging layer which, by analogy from applied geophysics, can be called the apparent thickness. This meant that the thickness could be determined on the basis of the default conceptual model rather than on real measurements. The presented method shows the potential for using the analysis of periodic oscillations in river reservoir level and nearby piezometers, as a method of monitoring riverbed clogging, in cases where periodical oscillations in reservoir level occur and observation wells are near enough to detect the oscillations.

Assessment of the need and potential for groundwater artificial recharge based on the water supply, water demand, and aquifer properties in a water shortage region of South Korea

Artificial recharge is increasingly necessary to ensure sustainable groundwater supplies and meet the needs of a growing population and crop cultivation in the age of climate change. In this study, artificial groundwater recharging using surplus water resources within the local area is considered for a water shortage area during a drought season, Shingok village, Hongsung-gun, South Korea, that lacks water sources. Based on an analysis of the monthly supply and demand with the water budget method, the current water supply is determined to be entirely dependent on groundwater wells, and water shortages occur in May (approximately 6446 m3) when rice planting begins. The surplus groundwater, which is the amount of natural recharge minus the present usage, and stream discharge are sufficient from December to June, so they are considered source waters for artificial recharge. A depth of 6 ~ 19 m is suggested as the main target region for recharge based on the composition of strata and the vertical distribution of the hydraulic conductivity, which was investigated with electric resistivity survey, drilling, and pumping test methods. Considering the permeability of layers, a vertical well, by which water can infiltrate directly into the target strata, is proposed as the main injection structure, and a ditch is also suggested as an auxiliary system to improve the effect of injection over a broad area. In the future, a detailed design for the injection scenario, injection facility, well and ditch arrangements, and pumping facility will be established through numerical modeling, field injection tests, etc. If it is impossible to obtain water from a long distance, an artificial recharge system based on local water sources may be an appropriate method of securing water considering the storage capacity of permeable strata.

Distribution of aquifer characteristics in different geomorphologic units in a granitic terrain

Knowledge of aquifer characteristics is essential for groundwater development and management studies. Detailed hydrological studies were carried out in a granitic terrain consisting of different geomorphologic units to resolve the coverage, performance, and characteristics of the aquifer parameters through the application of the pumping test method. An interpretation was performed by different methods, viz., Theis, Jacob, Hantush, and Rushton and Redshaw (numerical finite difference method) to ascertain the aquifer parameters. These parameters are vital for future groundwater development and management studies. Transmissivity (T) values estimated by Theis method range from 3.83 to 436 m2/day; 3.77 to 718 m2/day; and 16 to 160 m2/day, by Jacob method it ranges from 3.90 to 436 m2/day; 3.73 to 769 m2/day; and 17.3 to 152 m2/day, by Hantush method it ranges from 1.63 to 189 m2/day; 0.53 to 755 m2/day; and 19.3 to 118 m2/day, while by numerical method it ranges from 3 to 455 m2/day, 3 to 700 m2/day, and 17 to 148 m2/day in pediplain with moderate weathering (PPM), pediplain with shallow weathering (PPS), and buried pediplain with shallow weathering (BPPS) geomorphologic units, respectively. Similarly, a radius of influences ranges from 9.75 to 1391.0 m; 8.0 to 698.09 m, and 380.78 to 433.76 m in PPS, PPM, and BPPS geomorphologic units, respectively. The aquifer parameters obtained by the pumping tests were correlated with the structural features and different geomorphologic units. It was found that these parameters have wide variations within each geomorphologic feature. The radius of influence of each test well was calculated and compared with the in situ measured discharge of various wells within the area. The high values of transmissivity (T) are attributed to aquifer controlled by fractured zone in the area.

Identifikasi Karakteristik akuifer dan Potensi Air Tanah untuk Irigasi pada Sub DAS Data Kabupaten Wajo Sulawesi Selatan

Pengambilan airtanah secara berkelanjutan dapat dicapai jika terjadi keseimbangan antara pengambilan dan pengisian airtanah. Kemampuan akuifer dalam pelepasan airtanah yang mempengaruhi pengambilan dan pengisian airtanah tergantung pada karakteristik akuifer. Untuk itu, maka karakteristik suatu akuifer perlu diketahui agar jumlah pengambilan tidak melebihi daripada pengisian airtanah. Penelitian bertujuan untuk mengetahui posisi, ketebalan, jenis, hasil spesifik dan konduktifitas hidraulik akuifer serta mengidentifikasi daerah resapan sebagai sumber pengisian airtanah.dan potensi airtanah. Penelitian dilakukan dengan menginterpolasi data litologi dan pengukuran konduktivitas hidraulik akuifer dengan metode uji pemompaan. Nilai konduktivitas hidraulik diolah dengan menggunakan Solver Add Ins pada Microsoft Excel untuk mendapatkan nilai konduktivitas optimal. Sumber resapan airtanah diprediksi berdasarkan jejaring aliran data kontur muka airtanah dan potensi airtanah dihitung dengan pendekatan Darcy’s. Hasil penelitian menunjukkan bahwa konduktivitas hidraulik pada daerah penelitian sebesar 16,13 m/hari, hasil spesifik sebesar 0,32 dengan akuifer berupa pasiran. Berdasarkan jejaring aliran, sumber resapan berasal dari sisi Barat DAS mengalir ke arah timur dengan potensi sebesar 14.517 m3/hari ≈ 168,02 lt/dt.

Hydrogeologic and hydraulic characterization of aquifer and nonaquifer layers in a lateritic terrain (West Bengal, India)

The hydrogeologic and hydraulic characteristics of a lateritic terrain in West Bengal, India, were investigated. Test drilling was conducted at ten sites and grain-size distribution curves (GSDCs) were prepared for 275 geologic samples. Performance evaluation of eight grain-size-analysis (GSA) methods was carried out to estimate the hydraulic conductivity (K) of subsurface formations. Finally, the GSA results were validated against pumping-test data. The GSDCs indicated that shallow aquifer layers are coarser than the deeper aquifer layers (uniformity coefficient 0.19–11.4). Stratigraphy analysis revealed that both shallow and deep aquifers of varying thickness exist at depths 9–40 and 40–79 m, respectively. The mean K estimates by the GSA methods are 3.62–292.86 m/day for shallow aquifer layers and 0.97–209.93 m/day for the deeper aquifer layers, suggesting significant aquifer heterogeneity. Pumping-test data indicated that the deeper aquifers are leaky confined with transmissivity 122.69–693.79 m2/day, storage coefficient 1.01 × 10−7–2.13 × 10−4 and leakance 2.01 × 10−7–34.56 × 10−2 day−1. Although the K values yielded by the GSA methods are generally larger than those obtained from the pumping tests, the Slichter, Harleman and US Bureau Reclamation (USBR) GSA methods yielded reasonable values at most of the sites (1–3 times higher than K estimates by the pumping-test method). In conclusion, more reliable aquifers exist at deeper depths that can be tapped for dependable water supply. GSA methods such as Slichter, Harleman and USBR can be used for the preliminary assessment of K in lateritic terrains in the absence of reliable field methods.

Determining sources of mine water based on hydraulic characteristics analysis of a fault system

To analyze mining hydrogeological conditions and determine the sources of mine water, a hydrothermal deposit of China is taken as an example in this paper. On the basis of detailed geological and hydrogeological analysis of conditions in the mining area, the hydrogeological characteristics of a fault system of F1 in this mine are determined using a pumping test method and isotope technology. Hydraulic connections between the Majiagou group and Xiaoxian group are given a detailed illustration. The results show that the F1 group of faults is channeling water. Under significant drawdown, fissure water and Lower Pleistocene porous confined water are indirect sources of mine water, but water supply in unit time is limited. According to the analysis results, water will enter the pit during mining at a rate of 12,680 m3/d. In contrast, if the transmission performance of the F1 group of faults is ignored, the porous confined water will not enter the pit, and the mine water inflow will be 9700 m3/d. This is a decrease of 2980 m3/d, accounting for 30.72 % of mine water inflow. Therefore, the effect of water sources on mine water inflow cannot be ignored.

Characterization of aquifer parameter in basaltic hard rock region through pumping test methods: a case study of Man River basin in Akola and Buldhana Districts Maharashtra India

Aquifer parameters transmissivity ‘T’ and storage coefficient ‘S’ are very important parameters to assess the groundwater potential either through mathematical modeling or any conventional methods. In early days, these parameters are estimated either by means of in situ test or performing test on aquifer samples brought in the laboratory. In recent times, the pumping test has become an important method to estimate these parameters. This is the only method that provides simultaneous information on the hydraulic behavior of the well (borehole), the reservoir and the reservoir boundaries, which are essential for efficient aquifer and well field management. The applicability of the result from the laboratory test has limitations while in situ tests give representative aquifer parameters. The most common in situ test is pumping test performed on wells, which involves the measurement of the fall and rise of water level with respect to time. Theis (American Geophysics Union Transcripts, 16th annual meeting, part 2, pp 519–524, 1935) was first to propose method to evaluate aquifer parameters from the pumping test on a bore well in a confined aquifer. Since then, several methods have been developed to analyze the pumping test data (time-drawdown) under different conditions. For the characterization of the aquifer parameters in Man River basin area, it is essential to know the Transmissivity (T = Kb where, b is the aquifer thickness: pumping flow rate, Q = TW (dh/dl) flow through an aquifer) and Storativity (confined aquifer, S = bSs, unconfined, S = Sy) so as to predict the rate of drawdown of the water table/potentiometric surface during the pumping of an aquifer. The determination of aquifer’s parameters is an important basis for groundwater resources evaluation, numerical simulation, development and protection as well as scientific management. Pumping test is a main method for determining aquifer’s parameters. A study area shows that this method has rapid speed and high accuracy. The results of parameter’s determination are optimized so that it has important practical value for scientific research and engineering practice.

Numerical study identifying the factors causing the significant underestimation of the specific discharge estimated using the modified integral pumping test method in a laboratory experiment

A three-dimensional finite element model is constructed to simulate the experimental conditions presented in a paper published in this journal [Goltz et al., 2009. Validation of two innovative methods to measure contaminant mass flux in groundwater. Journal of Contaminant Hydrology 106 (2009) 51–61] where the modified integral pumping test (MIPT) method was found to significantly underestimate the specific discharge in an artificial aquifer. The numerical model closely replicates the experimental configuration with explicit representation of the pumping well column and skin, allowing for the model to simulate the wellbore flow in the pumping well as an integral part of the porous media flow in the aquifer using the equivalent hydraulic conductivity approach. The equivalent hydraulic conductivity is used to account for head losses due to friction within the wellbore of the pumping well. Applying the MIPT method on the model simulated piezometric heads resulted in a specific discharge that underestimates the true specific discharge in the experimental aquifer by 18.8%, compared with the 57% underestimation of mass flux by the experiment reported by Goltz et al. (2009). Alternative simulation shows that the numerical model is capable of approximately replicating the experiment results when the equivalent hydraulic conductivity is reduced by an order of magnitude, suggesting that the accuracy of the MIPT estimation could be improved by expanding the physical meaning of the equivalent hydraulic conductivity to account for other factors such as orifice losses in addition to frictional losses within the wellbore. Numerical experiments also show that when applying the MIPT method to estimate hydraulic parameters, use of depth-integrated piezometric head instead of the head near the pump intake can reduce the estimation error resulting from well losses, but not the error associated with the well not being fully screened.

Comparison of hydraulic conductivities by grain-size analysis,pumping, and slug tests in Quaternary gravels, NE Slovenia

Abstract Hydraulic conductivities (K) can be obtainedfrom pumping and slug tests as well as grain size analysis.Although empirical methods for such estimations are longstanding,there is still insufficient comparison of K valuesamong the various approaches. Six grain-size analysismethods were tested on coarse-grained alluvial sedimentsfrom 12 water wells in NE Slovenia. Values of K from grainsizemethods were compared to those of pumping testsand slug tests. Six grain-size methods (USBR, Slichter,Hazen, Beyer, Kozeny-Carman, and Terzaghi) were usedfor comparison with the Theis and Neuman pumping testmethod and the Bouwer-Rice method for slug tests. Theresults show that the USBR (US Bureau of Reclamation)method overestimates K values and there is no correlationwith other results, so its use is not advised. Conversely,whilst the Slichter method gives much lower estimatesof K, it is the only one to completely fulfill the grainsize requirements. Other methods (Hazen, Beyer, Kozeny-Carman, and Terzaghi) result in intermediate values andare similar to the Slichter method; however they should beused for smaller-sized sediments. Due to their high transmissivityand small radius of inffiuence, slug tests shouldbe avoided in the analysis of gravels, as they only test asmall portion of the aquifer compared to pumping tests.This is confirmed by the low correlation coefficients betweenhydraulic conductivities obtained from pumpingtests and slug tests.

Hydrogeophysical investigation of aquifer properties and lithological strata in Abraka, Nigeria

The purpose of this study is to investigate the aquifer properties and lithological strata of Abraka, Nigeria. This was carried out by employing the geoelectric, geophysical well logging and pumping test methods. Ten vertical electrical soundings using the Schlumberger configuration were occupied to investigate the geoelectric properties of the subsurface, while two wells were drilled to evaluate the lithology and aquifer parameters of the study area. The result of the lithological study showed that the subsurface formations consist of lateritic sand, fine and medium grain sand mixed with clay, coarse sand, medium coarse sand and very coarse sand. The interpretation of the geoelectric data using a combination of curve matching and Win Resist computer iteration showed close correlation with the well record. The geoelectric result revealed that the fifth layer with a resistivity range of between 509 and 1033Ωm and a depth range of between 31.5 and 45.9m is the preferred layer to source for good quality water in the area. The result of well logs also showed that the electrical conductivity and the total dissolve solid which were obtained as 0.0105mS/m and 67.43mg/m3 respectively falls within the World Health Organisation benchmark for potable water. The result of pumping test further revealed that the transmissivity, storativity and specific capacity of the aquifer are 0.0713m2/min, 1.3×10−5 and 0.39m2/min respectively. It is inferred from this survey that the aquifer is confined and capable of yielding adequate and good quality water for the people.