Constant-rate Pumping Research Articles

New Analytical Solutions for Constant Rate Pumping in Two‐Zone Double‐Porosity Confined Aquifer: A New Source Term Reflecting Effects of Well Skin and Wellbore Storage

AbstractThis study develops two new analytical models for constant rate pumping at a partially penetrating well in a double‐porosity confined aquifer, considering skin and formation zones. One model, referred to as the two‐zone model, incorporates a flow equation to depict the flow in the skin around the well. The other model, named the source‐term model, introduces a novel source term at the outer rim of the skin to reflect the effects of both the skin and wellbore storage. The analytical solutions for both models are derived by the Laplace transform and finite Fourier cosine transform. Additionally, a finite element solution for the source‐term model is presented. Results suggest the source‐term model is suitable to most wells when the width of the skin is less than 1 m and the radius of influence exceeds the outer rim of the skin. Temporal drawdown distribution for a negative skin exhibits a triple‐humped shape with two flat stages, while that for a positive skin shows monotonous increase. The source‐term model enables orthogonal 5 × 5 nodes for finite element approximation to discretize a well and its adjacent skin. The finite element solution aligns with early drawdown data measured at an observation well under the effects observed in two field constant rate pumping tests. In conclusion, this study introduces a novel approach to modeling two‐zone flow, which may find practical utility in field applications.

Splay aligned liquid crystal network photoactuators for integrated microfluidic pumps

As lab-on-a-chip devices aim to incorporate complex and multi-step microfluidic workflows, active fluid control within these platforms is critical. We use a splay aligned liquid crystal network (LCN) photoactuator, capable of deformation upon blue light illumination, as a stimuli responsive material to create integrated fluidic elements. After optimization of the manufacturing parameters, a well-defined actuator material is attained. Illumination with a 455 nm light emitting diode (LED) at 41 mW cm−2 achieves deflection of a 3 × 8 × 0.05 mm LCN film by 380 µm, generating forces of 1.1 mN. The actuator response is stable over time and scalable by light intensity, temperature, and size of the LCN film. By combining with a polydimethylsiloxane (PDMS) membrane, integration into a microfluidic chip is demonstrated and fluid movement of 77 nL in a 2 s stroke is attained. In a pumping setup, the LCN film functions as pumping membrane and two passive PDMS check valves complete the integrated micropump. Constant pumping rates of 0.1 µL min−1 are achieved. An advantage of this micropump setup lies in the non-contact actuation method, which allows for easy integration into microfluidic chips, without the need for chip-to-world connections. Furthermore, with the simple manufacturing procedure and the low operating power, important requirements for application in point-of-care settings are fulfilled.

Effect of methoxymine on prevention and treatment of myocardial injury and cardiac function in elderly patients with hypotension during intraspinal anesthesia.

We aimed to investigate the effects of methoxamine to prevent hypotension in the elderly with intraspinal anesthesia (IA) on myocardial injury and cardiac function. A retrospective study was conducted by enrolling sixty elderly patients who underwent femoral head replacement (FHR) under IA in our hospital from August 2019 to August 2020. The patients were divided into two groups according to the random number table method. In the control group (CG) (30 patients), 5 mg of ephedrine was administered sedately when patients developed hypotension (20% below basal blood pressure). In the research group (RG) (30 cases), 2 μg/(kg·h) of methoxamine hydrochloride was given as a constant-rate pump before anesthesia, and 1 mg of methoxamine hydrochloride was administered intraoperatively if hypotension occurred. The hemodynamic [systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR)], myocardial injury indexes [cardiac troponin I (cTnI), creatine kinase isoenzyme MB (CK-MB), fatty acid binding protein (FABP), plasma amino-terminal brain natriuretic peptide precursor (NT-proBNP)], cardiac function indexes [systemic vascular resistance (SVR), stroke volume (SV), net percentage ejection time (ET)] were observed before anesthesia (T1), at the end of surgery (T2), and 6 h after surgery (T3) in both groups. The Bruggemann Comfort Score (BCS) and Visual Analog Scale (VAS) scores at T3, 12 h postoperatively (T4) and 24 h postoperatively (T5) in both groups were observed, and the incidence of adverse reactions to intralesional anesthesia in both groups was counted. SBP, DBP and HR at T2 were lower than those at T1 in both groups, and SBP, DBP and HR at T3 were higher than those at T2, and SBP, DBP and HR at T2 and T3 in the RG were higher than those in the CG (p<0.05). In both groups, cTnⅠ, CK-MB and FABP were higher at T2 and T3 than at T1, higher at T3 than at T2, and NT-proBNP was higher at T2 than at T1 and T3, and lower in the RG than in the CG (p<0.05). In both groups, SVR and SV at time point T2 were lower than at time point T1 and ET was higher than at time point T1, SVR and SV at time point T3 were higher than at time point T2 and ET was lower than at time point T2, SVR and SV in the RG were higher than in the CG and ET was lower than in the CG (p<0.05). VAS scores were higher in both groups at T4 and T5 than at T3, and lower in the RG than in the CG (p<0.05). Methoxamine can effectively reduce the risk of hypotension in geriatric endotracheal anesthesia, which can reduce myocardial injury and stabilize cardiac function in patients.

Determination of Aquitard Storage from Pumping Tests in Leaky Aquifers

The management of groundwater resources requires a thorough understanding of groundwater flow and storage. Aquitards, in particular, can store large amounts of groundwater, but are generally often overlooked or ignored in groundwater surveys. In this study, we show how a pumping test performed in a leaky aquifer can be used to estimate the storage coefficient of an overlying aquitard. A new analytical solution is presented for a constant-rate pumping test in a leaky aquifer taking into account the water released from storage in the aquitard. The utility of the method is demonstrated by a practical application using data from a pumping test conducted in a semi-confined sandy aquifer overlain by an aquitard consisting of a mixture of clay and sand. The results obtained show that the solution enables the accurate calculation of the storage properties of the aquitard.

Estimating Hydraulic Parameters of Aquifers Using Type Curve Analysis of Pumping Tests with Piecewise-Constant Rates

Aquifer hydraulic parameters play a critical role in investigating various groundwater hydrology problems (e.g., groundwater depletion and groundwater transport), and the Theis formula for constant-rate pumping tests is commonly used to estimate them. However, the pumping rate in the field usually varies with time due to some factors, making the classical constant-rate model unsuitable for accurate parameter estimation. To address this issue, we developed a novel dimensionless-form analytical solution for variable-rate pumping tests involving piecewise-constant approximations for variable pumping rates. Analysis of the time–drawdown curves revealed that the first-step type curve was consistent with the Theis curve. However, the curves of subsequent steps deviated from the Theis curve and were associated with the first dimensionless inflection time (t1,D), which depended on the hydraulic conductivity (K) and specific storage (Ss) of the confined aquifers. On this basis, a new type curve method for estimating the aquifer K and Ss was proposed by matching the observed drawdown data with a series of type curves dependent on t1,D. Furthermore, this method can handle recovery drawdown data. We applied this method to a field site in Wuxi City, Jiangsu Province, China, by analyzing the drawdown data from four pumping tests. The hydraulic parameters estimated using this method were in close agreement with those calibrated via PEST. The calibrated K values were further validated by comparing them with lithology-based results. In summary, the geometric means of K and Ss were 6.62 m/d and 3.16 × 10−5 m−1 for the first confined aquifer and 0.92 m/d and 2.34 × 10−4 m−1 for the second confined aquifer.

Solutions for Groundwater Flow to a Pumping Well with an Exponentially Decreasing Variable-Rate in a Sloping Aquifer.

During aquifer pumping tests in the field, the attenuation process of the pumping rate is generally monitored, and the aquifer may be slanted, especially in riverbank terraces, piedmont plain and other similar terrains. The combination of these two factors (attenuation process and aquifer slope) has not received enough academic attention, therefore, a two-dimensional groundwater flow model is developed for an exponentially decreasing variable rate pumping well in a sloping aquifer in this study. The new semi-analytical solution (based on a linearized free-surface boundary) is obtained using the Laplace transform and finite Fourier cosine transform. Meanwhile, to depict the linearized boundary precisely with the first-order free surface equation, a numerical model that considers the decline of the water table is also developed. Results show that under the effect of the variable rate, the time-drawdown curve presents a downward trend at intermediate times. Additionally, the error caused by the linearization of the free-surface equation on the analytical model is found to be acceptable except when the sloping angle is larger than π/6. Furthermore, since this study extends the work of Huang et al. (2014), who considered a constant pumping rate, the new solution was found better to interpret real pumping test data reported by Antonio and Pacheco (2002), and the laboratory experiment results. Overall, the new solution proves to be useful for parameter inversion accurately as the average pumping rate tended to underestimate hydraulic parameters when fitting short-term pumping data.

Analytical and numerical analysis of constant-rate pumping test data considering aquifer boundary effect

Analytical and numerical analysis of constant-rate pumping test data considering aquifer boundary effect

Investigating and Managing the Impact of Using Untreated Wastewater for Irrigation on the Groundwater Quality in Arid and Semi-Arid Regions.

This study aims to investigate the impact of using untreated wastewater in irrigation. Different scenarios of management were applied by mixing it with treated wastewater or freshwater on groundwater quality. A hypothetical case study is presented. The numerical model of MODFLOW is used in the simulation by applying four stages (21 scenarios) including: different values of pumping rates, changing wastewater recharge rates, and a combination of the previous scenarios. Additionally, protection scenario for groundwater was applied by using different values of mixing of freshwater with wastewater. The simulation was carried out for the contamination of Chemical Oxygen Demand COD and the concentration reached 48.6 ppm at a depth of 25 m and 19.41 ppm at a depth of 50 m in the base case. The results showed a negative impact on groundwater quality had occurred due to increasing the pumping rates, wastewater recharge rates, and combination between two scenarios, which led to an increase of the contaminants in the aquifers. However, positive protection effects occurred due to mixing the wastewater with treated wastewater. The results of COD concentration in groundwater using treated wastewater reached 81.82, 77.88, 74.03, 70.12, and 66.15 ppm at a depth of 25 m and 53.53, 50.95, 48.43, 45.87, and 43.28 ppm at a depth of 50 m, at concentrations of 93, 88.52, 84.14, 79.7, and 75.19 ppm with constant pumping and recharge rates of 4320 m3/d and 547.5 mm/year, respectively. The using of treated wastewater could improve the groundwater quality to be used in the irrigation process and help to minimize groundwater contamination. Moreover, the abstraction of the groundwater should be optimized, and the qualities of wastewater should be constrained in agriculture to protect the groundwater quality.

Analysis of Groundwater Flow Modelling: The Case of Hormat-golina Sub-basin, Golina Basin, Ethiopia

Analysis of the Groundwater flow can help to understand future water potential. This study has explored the predicted groundwater flow dynamics with climate change and anthropogenic stress in Hormat-Golina Sub-basin. Groundwater flow modeling in this Sub-basin has provided information about groundwater quantity as well as the quality aspect for decision-makers about groundwater accessibility. The initial head measured values before and after irrigation season has varied to a maximum of 0.8 m. The groundwater head level before and after irrigation season was varying from 9.3 m to 8.26 m in the Southern boundary. The groundwater head was obtained from 41.5 m to 38.83 m in the northwestern of the Sub-basin. The maximum drawdown depth had found to 0.27 m and 2.6 m before and after irrigated season around the pumped wells. The increased pumping rate with decreased recharge rate was replying to the groundwater head at the end of 2021 decreased by 2.81 m in the northwestern boundary of the Sub-basin as compared as using constant pumping rate with recharge rate. While decreased pumping with increased recharge rate was replying to the groundwater head at the end of 2021 has increased by 2.23 m in the northwestern boundary of the Sub-basin as compared as using constant pumping rate. The impacts of climate change and human pressure on groundwater begot as the threats in those supply wells. Decreased pumping with increased recharge rate was accomplishing to restore and protect the groundwater resources, which is the best option for groundwater restoration and monitoring.

The Effects of Fault-Zone Cementation on Groundwater Flow at the Field Scale.

Fault zones are an important control on fluid flow, affecting groundwater supply, contaminant migration, and carbon storage. However, most models of fault seal do not consider fault zone cementation, despite the recognition that it is common and can dramatically reduce permeability. In order to study the field-scale hydrogeologic effects of fault zone cementation, we conducted a series of aquifer pumping tests in wells installed within tens of meters of the variably cemented Loma Blanca Fault, a normal fault in the Rio Grande Rift. In the southern half of the study area, the fault zone is cemented by calcite; the cemented zone is 2-8 m wide. In the center of the study area, the cemented fault zone is truncated at a buttress unconformity that laterally separates hydrostratigraphic units with a ∼40X difference in permeability. The fault zone north of the unconformity is not cemented. Constant rate pumping tests indicate that where the fault is cemented, it is a barrier to groundwater flow. This is an important demonstration that a fault with no clay in its core and similar sediment on both sides can be a barrier to groundwater flow by virtue of its cementation; most conceptual models for the hydrogeology of faults would predict that it would not be a barrier to groundwater flow. Additionally, the lateral permeability heterogeneity across the unconformity imposes another important control on the local flow field. This permeability discontinuity acts as either a no-flow boundary or a constant head boundary, depending on the location of pumping.

Combination of Pre-Pulse and Constant Pumping Rate Hydraulic Fracturing for Weakening Hard Coal and Rock Mass

The weakening of hard coal–rock mass is the core common problem that is involved in the top coal weakening in hard and thick coal seams, the hard roof control during the initial mining stage in the longwall mining face, and the hanging roof control in the gob of non-coal mine. Based on the characteristics of pulse hydraulic fracturing and constant pumping rate hydraulic fracturing, a weakening method for hard coal–rock mass by combining pre-pulse and constant pumping rate hydraulic fracturing is proposed. A complete set of equipment for the combined pulse and constant pumping rate hydraulic fracturing construction in the underground coal mine is developed. The pulse and constant pumping rate hydraulic fracturing technology and equipment were applied in the top coal weakening of the shallow buried thick coal seam. Compared with no weakening measures for top coal, the average block size of the top coal caving was reduced by 42% after top coal hydraulic fracturing. The recovery rate of the top coal caving mining face reached 85%, and it increased by 18% after hydraulic fracturing.

Evaluating the Impacts of Pumping on Aquifer Depletion in Arid Regions Using MODFLOW, ANFIS and ANN

In arid regions, the groundwater drawdown consistently increases, and even for a constant pumping rate, long-term predictions remain a challenge. The present research applies the modular three-dimensional finite-difference groundwater flow (MODFLOW) model to a unique aquifer facing challenges of undefined boundary conditions. Artificial neural networks (ANN) and adaptive neuro fuzzy inference systems (ANFIS) have also been investigated for predicting groundwater levels in the aquifer. A framework is developed for evaluating the impact of various scenarios of groundwater pumping on aquifer depletion. A new code in MATLAB was written for predictions of aquifer depletion using ANN/ANFIS. The geotechnical, meteorological, and hydrological data, including discharge and groundwater levels from 1980 to 2018 for wells in Qassim, were collected from the ministry concerned. The Nash–Sutcliffe efficiency and mean square error examined the performance of the models. The study found that the existing pumping rates can result in an alarming drawdown of 105 m in the next 50 years. Appropriate water conservation strategies for maintaining the existing pumping rate can reduce the impact on aquifer depletion by 33%.

Non-Darcian effect on a variable-rate pumping test in a confined aquifer

Groundwater flow in an aquifer has frequently been found to be non-Darcian. In this study, a transient model of a variable-rate pumping test in a confined aquifer was established considering non-Darcian flow in the aquifer. A piecewise-linear function was adopted to reproduce the variability in pumping rate, and the classical Izbash equation was employed to describe the non-Darcian flow. The type-curve analysis suggested that a smaller quasi-conductivity will result in an earlier deviation and a smaller extent of the decreasing features in the drawdown under the condition of a linearly decreasing pumping rate compared to that under the condition of a constant pumping rate. The sensitivity analysis indicated that the variability in pumping rates under non-Darcian flow can increase the sensitivity of drawdown to the radius of the well casing at inflection times of the discrete linear stages, and drawdown closer to the pumping well is more sensitive to the change in the well casing. A type-curve method was proposed and employed to interpret the pumping test data, which were collected at a field site located in Wuxi city, Jiangsu Province, China. The parameter estimates indicate a high possibility of the occurrence of prelinear flow in the aquifer of interest.

New Semi-Analytical Model for an Exponentially Decaying Pumping Rate with a Finite-Thickness Skin in a Leaky Aquifer

AbstractPumping tests are commonly used to estimate aquifer parameters during field work. Classical pumping tests are mainly classified into two general types: constant-rate pumping tests and const...

Optimized Pumping Strategy for Reducing the Spatial Extent of Saltwater Intrusion along the Coast of Wadi Ham, UAE

Many coastal aquifers are facing severe anthropogenic impacts such as urbanization, industrialization and agricultural activities are resulting in a saltwater intrusion. This establishes the need for a sustainable groundwater management strategy aimed to overcome the situation. Pumping of brackish/saline water to mitigate saltwater intrusion is a major potential approach to effectively control saltwater intrusion. However, this method has many challenges including selection of appropriate discharge rates under an optimum number of pumping wells and at specified wells distance from the shoreline. Hence, this study developed a Finite Element Flow and solute transport model (FEFLOW) to simulate three scenarios to assess the most appropriate pumping rates, number of wells and optimum well locations from the shoreline. These parameters were assessed and evaluated with respect to the change in groundwater saline concentration at different distance from the coastline. The 15,000 mg L−1 isosalinity contour line was used as a linear threshold to assess the progression of saltwater intrusion along three major locations in the aquifer. Scenario One was simulated with a constant number of wells and rate of pumping. Shifting of pumping wells to several distances from the shoreline was conducted. Scenario Two assessed the most appropriate number of pumping wells under constant pumping rates and distances from the shoreline and in scenario 3, the optimum pumping rates under a constant number of wells and distance from the shoreline were simulated. The results showed that the pumping of brackish/saline water from a distance of 1500 m from the shoreline using 16 pumping wells at a total pumping rate of 8000 m3 d−1 is the most effective solution in contrasting the saltwater intrusion in the Wadi Ham coastal aquifer.

Three-dimensional response to a partially penetration well pumping in a general anisotropic three-layer aquifer system

Three-dimensional response to well pumping in a multilayer aquifer system with rigorous treatment of interfacial flow attracts great attention among the subsurface hydrologists because of its theoretical importance and practical merits. In this study, a general theory of three-dimensional groundwater flow to a well of infinitesimal radius in an anisotropic three-layer aquifer system is developed with a constant-rate pumping in the lower layer, and associated semi-analytical solutions of drawdowns in individual layers are obtained. This theory discards many previous assumptions for studying a multilayer aquifer system such as simplified flow configuration in the aquitard, treatment of cross-formation flow as a volumetric averaged term adding to the governing equations of aquifer flows, and sometimes negligence of vertical flow components in the aquifers. Additionally, this theory considers three types of commonly used top boundary conditions: A water table with delayed gravity drainage boundary condition (Case 1), a constant-head top boundary condition (Case 2), and a no-flow top boundary condition (Case 3). The dimensionless drawdown solutions in Laplace domain are obtained and inverted numerically to calculate the time-domain solutions. The solution encompasses existing solutions for a two-layer or a single-layer (e.g. unconfined or confined) aquifer system as subsets. The developed solutions are tested extensively with a finite-element numerical solution using COMSOL and other existing solutions, and a sensitivity analysis is performed to prioritize the influences of different parameter groups. The results of this study can be used to predict the pumping induced drawdown at any position with an observation well, and to estimate the hydraulic parameters of the lower pumped layer and upper layer, as well as the middle layer. The developed theory provides a basis for other potential applications such as geotechnical engineering and groundwater management.

A Type-Curve Method for the Analysis of Pumping Tests with Piecewise-Linear Pumping Rates.

Aquifer hydraulic parameters are commonly inferred from constant-rate pumping tests, while variable pumping rates are frequently encountered in actual field conditions. In this study, we propose a generally applicable dimensionless form of the analytical solution for variable-rate pumping tests in confined aquifers. In particular, we adopt a piecewise-linear fitting of variable pumping rates and propose a new type-curve method for estimating the hydraulic conductivity (K) and specific storage (Ss ) of the investigated confined aquifer. For each test, a series of type curves, which depend on the variable pumping rates, the location of observation wells and the introduced first dimensionless inflection time, need to be provided for matching the observed drawdown data on a log-log graph. We first demonstrate the applicability and robustness of this method through a synthetic pumping test. Subsequently, we apply this method to analyze drawdown data from four pumping tests conducted within a multilayered aquifer/aquitard system in Wuxi city, Jiangsu Province, China. The parameter estimates are then compared with those reported by PEST. The K and Ss values estimated by the new type-curve method are found to be quite close to PEST-based estimates. Parameter estimation results demonstrate the difference in K and Ss values between observation wells. The difference could be attributed to the spatial heterogeneity in K and Ss . A future research topic may focus on the characterization of K and Ss heterogeneity with the currently available drawdown data from variable-rate pumping tests.

Chronic Staphylococcus aureus Superantigen Toxic Shock Syndrome Toxin-1 Exposure Accelerates the Progression of Atherosclerosis in Rabbits.

It has been reported that infectious agents contribute to the atherosclerotic process. However, it is unclear whether Staphylococcus aureus superantigen (SAg) toxic shock syndrome toxin-1 (TSST-1) has an effect on atherosclerosis progression. The present study was designed to investigate the pathogenic role of TSST-1 exposure in the atherosclerotic process in rabbits. New Zealand White rabbits were exposed to TSST-1 through Alzet miniosmotic pumps with a constant pumping rate. Aortic atherosclerosis was evaluated by histological and morphometric methods. Using a biochemical analyzer/enzyme-linked immunosorbent assay/immunostaining, we further analyzed various atherosclerosis-related factors. The gross atherosclerotic lesion area in the aortic arch increased by 15.3% in high-fat-diet rabbits exposed to TSST-1 compared to that in the control group. In the atherosclerotic lesions, TSST-1 exposure increased the content of smooth muscle cells. Moreover, TSST-1 treatment up-regulated serum tumor necrosis factor alpha (TNF-α) level, but did not affect serum lipids (except for triglycerides) and endotoxin in the rabbits. Our data validated that chronic stimulation with TSST-1 facilitates the progression of atherosclerosis in rabbits independently of endotoxins, indicating that S. aureus and its SAgs may be targets to prevent and treat atherosclerosis.

Analysis of the impact of hydraulic properties and climate change on estimations of borehole yields

Understanding the impact of climate change on borehole yields from fractured aquifers is essential for future water resources planning and management. Although variation in hydraulic conductivity with depth (VKD) in fractured aquifers is a well-known phenomenon, the relative significance of climate change and VKD on borehole yield estimates is poorly understood. We hypothesize that VKD exerts a significant additional control on borehole yields under climate change that has not been considered in yield assessments to date. We developed a simple two-layered radial groundwater flow model of an idealised pumping borehole in the fractured Chalk aquifer of south-east England, and applied 11 VKD profiles based on a simple conceptual representation of variation in hydraulic conductivity with depth in the Chalk. For each time step, the transmissivity is calculated by integrating the VKD profile over the saturated depth calculated at the previous time step. For each VKD profile and resulting transmissivity, we applied 20 climate scenarios and six constant pumping rates for the period 1962–2014. We then estimated borehole yields based on the derived lowest pumping water levels during key drought years (e.g. 1976). We show that the hydraulic properties of the aquifer are more significant (p < 0.001) than changes in climate (p > 0.1) in controlling lowest pumping groundwater levels when abstraction rates are <9000 m3/day, and that both are significant when abstraction ≥9000 m3/day. Hydraulic conductivity is as significant a control as climate on borehole yields, although responses are non-linear associated with whether pumping water level-pumping rate curves intersect key yield constraints (e.g. pump intake depth, major inflow horizons). It is recommended that variations in hydraulic conductivity with depth are taken into consideration in future assessments of borehole yields under climate change. The approach presented is generic and can be applied across different aquifers where vertical heterogeneity is present and affects transmissivity.

Determination of Groundwater Potentials in Crystalline Basement Areas of Bauchi Local Government Area, Bauchi

Developing groundwater is generally an excellent option for sustainable water supplies in Bauchi due to the ephemeral nature of surface water. However, the large variability in geological and hydrological conditions have a profound influence on the availability of groundwater across the study area. The rationale for this research is to contribute at least, in terms of providing empirical data towards sustainable development of groundwater resource, particularly in the Crystalline Basement hydrogeological unit of Bauchi area. Aquifer properties of wells within the Crystalline Basement were estimated from a constant-rate pumping test of 10 sampled wells by fitting mathematical models (type curves) to drawdown data through curve matching. Generally, yields of sampled boreholes within the crystalline basement aquifer range from 8.64 m 3 /d to 120.96 m 3 /d with an average of 52.36 m 3 /d. The total yield of the boreholes is about 661.83.m 3 /day. This can sustain a population of 26,473 based on water supply standard of 25 litres per day for rural communities (Babatola, 1997). Considering the total population of 12,218 people (NPC, 2014) that are currently using the water points in comparison to water supply standard of 25 litre per person per day, this shows that the aquifers from the 10 sampled boreholes have relatively enough groundwater in terms of yield to meet the water need of the population. However, any significant increase in population growth may result in water scarcity in these areas, as the Crystalline Basement aquifers generally have low yielding capacity. Also, the crystalline basement aquifer properties evaluated reveal that the transmissivity values range from 2.55 m 2 /day to 111.0 m 2 /day with an average of 38.94m 2 /day (Table 5). According to Offodile (2002), a transmissivity range of 5 to 50 m 2 /day could be regarded as high potential in crystalline rock situations. By the above standard, the crystalline basement aquifers in the area are classified as aquifers of negligible to high potentials. The specific capacities of boreholes in the study area were computed and the results show that they vary between 1.30 to 691.2 m 2 /d/m. Keywords: Crystalline Basement, Groundwater, Pumping Test, Aquifer, Transmissivity, Bauchi State, Nigeria DOI : 10.7176/JEES/9-7-02 Publication date :July 31 st 2019