Water Levels In Wells Research Articles

Different coseismic groundwater level changes in two adjacent wells in a fault-intersected aquifer system

Previous studies have investigated many cases regarding changes in well water level and attributed differences in the coseismic water level responses to various hydrogeological conditions. However, most of these studies often fail to provide insights into the responses of different portions of one groundwater system because the boreholes in question are usually located in different hydrogeological units with no hydraulic communication. This paper analyzes coseismic and postseismic variation characteristics of the water levels of two adjacent observation wells located near the same fault zone and separated by a distance of approximately 2 km. Well X10 resides in the fault zone and is indirectly connected to the aquifer, whereas Well X11 directly penetrates into the aquifer. Based on the coseismic static strain, seismic energy density and variation in well water level response to earth tides before and after earthquakes, this research investigates the effects of faults on coseismic well water level responses. The results show that under the effects of static compressive stresses, wells X10 and X11 present opposite water level responses due to the presence of the fault. After the earthquake, the water levels in both wells are elevated due to the increased aquifer permeability induced by the earthquake. Nevertheless, because of the fault, the rate of increase of the postseismic water level in Well X10 is obviously lower than that of Well X11. A seismic energy density analysis shows that only three near-field earthquakes with energy densities greater than 10−3 J/m3 can simultaneously trigger the elevation of coseismic water levels in wells X10 and X11. This paper concludes that the oscillation elevation of the coseismic water levels in wells X10 and X11 should be mainly attributed to the increased aquifer permeability. However, the mechanisms underlying this change are quite complex and cannot be explained by a single mechanism, and the increased permeability may be correlated to various factors, such as the coseismic static strain, seismic energy density and borehole condition.

Aquifer Sensitivity to Earthquakes: The 1755 Lisbon Earthquake

AbstractThe development of a theoretical analytical model leads us to consider the recession coefficient as a useful hydrological parameter for studying the hydraulic impacts of an earthquake on spring flow in terms of the increase of persistent discharges and the overall alteration of springs. Both the inertia of the aquifer emptying and the increased pore pressure in the lower part of the aquifer caused by the earthquake contribute to maintaining the discharge of persistent springs. Abundant information on the hydrological phenomena induced or modified by the 1755 Lisbon earthquake (M ∈ [8,9]) and its relationship with present‐day knowledge of the geology and hydrogeology of Portugal and Spain, as well as Spanish spring statistics, have allowed us to identify the factors that most influence the hydraulic sensitivity of aquifers to that earthquake: regional faults, geological boundaries between large geological units, the granite lithology, and aquifers with high recession coefficients. We observe an overall single response, which was an increase in postseismic spring discharges over the entire of the SW quadrant of the Iberian Peninsula (1–24 months). The persisting discharges were concentrated close to the major NE‐SW directional faults located in SW Portugal that are linked to the Azores‐Gibraltar strike‐slip fault. In terms of the geographical distribution of the hydrological phenomena, we observe that in the near and intermediate field of the earthquake source, there were persistent increases in spring flow in hard rocks occurring alongside persistent diffuse discharges, liquefaction, and rising water levels in wells due to consolidation of superficial geological formations.

Improvement of the method for determining the values of water levels decrease in vertical wells of group water intake

Purpose. Studying disciplines related to water supply sources and water intake facilities implies the practical familiarization of students with methods for choosing the type of water intake, determining their characteristics, calculating the main parameters and selecting the appropriate equipment. The complexity of the calculations of group water intake is to account for the large number of interrelated hydrogeological characteristics of the aquifer and the location of the wells in it. Evaluation of the qualitative effect of these values on the productivity of the wells will allow to optimize the calculation method, reduce time and labour intensity, and work out the proposals for possible changes in the estimated productivity by more active variation of the determining parameters. Methodology. The analysis of the influence of determining factors on the productivity of group water intakes consisting of vertical tubular wells was used. An algorithm is proposed for making changes in the calculation methodology for determining the decrease of water levels in the wells of group water intakes. Results. It is established that the determination of the values of the decrease in water levels in the tubular wells of group water intakes is a rather complicated task, which requires experience in designing, accounting, and a repeatedly changing number of interrelated determining factors. It is shown that the need to change the values of technical parameters in the calculation method is preserved at all stages of the calculation. Nomograms were made to determine the dependence of the decrease in water levels in the main and affecting wells of group water intake on a number of factors. The nomogram to determine the dependence of the decrease of water levels in the main wells of the group water intake can be used to calculate single wells. The application of the research results allows us to optimize and speed up the calculation method, to make controlled changes to the final result changing individual factors of influence or their groups. Scientific novelty. The analysis of factors affecting the productivity of tubular wells as part of group water intakes was carried out. Recommendations are made to improve the design of water intake structures of the specified type. It is shown that the method of calculating group water intakes amounts to solve two problems − determining productivity and lowering the water levels in the main wells and the wells they affect. The separation of the calculation allows for a more detailed analysis and the use of the hydrogeological conditions for the placement of water intakes, the selection of the characteristics and parameters of individual wells. Practical relevance. Using the results of the analysis of the influence of individual factors on the value of productivity and lowering water levels in tubular wells as part of group water intakes made it possible to optimize the calculation method, to show possible directions for adjusting the value of productivity in real boundaries.

EPANET modeling of an urban groundwater field

The paper presents an EPANET model of a groundwater well field. The method used in the simulations to model the variation of the hydrodynamic levels in wells as a function of the pumped flow rate is discussed, and a comparison to previous simulations that used fixed hydrodynamic levels in the wells is performed. The case study points to a groundwater well field in Romania. The results show that the new method although requiring a more complex EPANET model, provides a solution that is closer to the actual variation of water levels in wells.

Tidal Response of Groundwater in a Leaky Aquifer—Application to Oklahoma

AbstractQuantitative interpretation of the tidal response of water levels measured in wells has long been made either with a model for perfectly confined aquifers or with a model for purely unconfined aquifers. However, many aquifers may be neither totally confined nor purely unconfined at the frequencies of tidal loading but behave somewhere between the two end‐members. Here we present a more general model for the tidal response of groundwater in aquifers with both horizontal flow and vertical leakage. The model has three independent parameters: the transmissivity (T) and storativity (S) of the aquifer and the specific leakage (K′/b′) of the leaking aquitard, where K′ and b′ are the hydraulic conductivity and the thickness of the aquitard, respectively. If T and S are known independently, this model may be used to estimate aquitard leakage from the phase shift and amplitude ratio of water level in wells obtained from tidal analysis. We apply the model to interpret the tidal response of water level in a US Geological Survey (USGS) deep monitoring well installed in the Arbuckle aquifer in Oklahoma, into which massive amount of wastewater coproduced from hydrocarbon exploration has been injected. The analysis shows that the Arbuckle aquifer is leaking significantly at this site. We suggest that the present method may be effective and economical for monitoring leakage in groundwater systems, which bears on the safety of water resources, the security of underground waste repositories, and the outflow of wastewater during deep injection and hydrocarbon extraction.

STUDY OF THE DEFORMATION MODE OF THE ROCK MASS BASED ON THE DATA OF UNDERGROUND WATER MONITORING AT THE SEMIPALATINSK TEST SITE

The paper proposes a scientific-methodological approach to determine the negative consequences of high-intensity impacts of large-scale explosions on the rock mass at the example of “Zarechye” site of the Semipalatinsk test site. The results of observations for the period of 1987–1990 over the underground water level in wells with depths from 75 to 200 m were used as the raw data. A comparative analysis of level alterations along a profile of reference wells is aimed to identify the areas of time-spatial redistribution of the underground flow. The change of hydrogeological condition is considered as an indicator of the changing deformation regime of the rock mass subjected to a high-intensity impact.

Identification of Individual Efficiency for Barometric Pressure and Ocean Tide Load Simultaneously Acted on Deep Aquifers Adjacent to the West Pacific Ocean

Groundwater fluctuation usually reflects the property of aquifer in nature. Actually, water level change can be caused not only by barometric pressure changes resulted from atmospheric motion, but also by the tidal effect from nearby marine system or water body. In confined aquifer, an increase in barometric pressure usually will cause a decrease in water level in well to an amount described by the barometric efficiency. The barometric efficiency can be also used as a correction factor to remove barometric effects on water levels in wells during an aquifer test. With the rise of the tidal sea on the coastal aquifer, it indicates that there will be compensating increases of water pressure and stress in the skeleton of aquifer. External forcing on groundwater level in the coastal aquifer, such as barometric effect and tidal sea, usually affect the water level to fluctuate with different phases to some extent. An adaptive adjustment to remove the combination of barometric and oceanic tidal efficiency is presented in this study. This research suggests that the presented formula can simultaneously identify the individual efficiency for barometric effect and load of tidal sea considering their combined observation of groundwater level in aquifer system. An innovative application has been demonstrated for the deep aquifers adjacent to the West Pacific Ocean.

Static and dynamic water wells levels of Kirkuk city represented by geo-statistical algorithms in GIS

Water is great importance for human life as well as for agriculture therefore, different scientific methods are used for curtailed the time and possibilities for well water sources investigation. Fresh water is the most importance for Human life and cannot be healthy without it. In the paper two different interpolation methods were used, which are the ordinary kriging and Inverse Distance Weighting (IDW) to predict static and dynamic water levels of wells in Kirkuk City, and the number of wells was 64. The data of wells were obtained from digging water wells in Directorate of Kirkuk. By using different methods different results were introduced. Furthermore, three wells were used as testing wells for interpolation algorithms.These are office of the Nation Mission, the Emergency department, and Wahid Athar district wells and it was found that the Emergency department well is the most accurate and nearest from the actual levels for both static and dynamic with RMSE of - 2.23 and - 1.35 in kriging method respectively as well as -2.97 and - 2.65 respectively in IDW method. However, the average of the three testing wells overall IDWinterpolation algorithm is the best, accurate and nearest from the true elevations in stable levels of wells.

EFFECTS OF THE JANUARY 30, 2016, Mw=7.2 ZHUPANOVSKY EARTHQUAKE ON THE WATER LEVEL VARIATIONS IN WELLS YUZ-5 AND E-1 IN KAMCHATKA

This paper describes the water level variations in wells YuZ-5 and E-1 inKamchatkaduring the Zhu­panovsky earthquake that occurred on January 30, 2016 (M w =7.2, Н =180 km). The distances from the Zhupanovsky earthquake epicenter to wells E-1 and YuZ-5 were 70 and 80 km, respectively. In well YuZ-5 , the water level raised by 9.4 cm during 45 minutes after the seismic wave arrival. This effect was caused by a combination of a co-seismic rise in the water level due to the volumetric compression of the water-bearing rocks during fracturing in the earthquake source and an impulse increase in the fluid pressure near the wellbore during the seismic shocks. We estimated the amplitude of the coseismic water level increase (D h =7.3 cm) and the strain value resulting from the volumetric compression of the water-bearing rocks, which is consistent with the estimated value of the coseismic volumetric deformation in the area of the well at the depth of 500m: D 1 = –4.5×10 –8 . This estimation was based on the model of the dislocation source in the homogeneous isotropic elastic half-space with the parameters of the Zhupanovsky earthquake focal mechanism. After the earthquake, the water level dropped for three months at an amplitude of about ~40 cm. In order to estimate the radius of the well sensitivity to the pressure drop source, we used the model of water level lowering that followed the pressure drop in the aquifer at a distance to the well as a result of the improved filtration properties of the water-bearing rocks after the seismic shocks. The estimated radius of the well sensitivity, R is 450 m. For 3.5 months before the Zhupanovsky earthquake, ~20 cm increase in the water level was observed, which is anomalous in comparison with the average seasonal variations of the water level, as shown by the long-term observations. In our opinion, such a rise in the water level occurred in the process of the earthquake preparation, and can thus be viewed as its precursor. In well E-1, a sequence of water level changes manifested a hydrogeodynamic precursor: the water level dropped at an increased rate for 21 days before the earthquake, and raised at an amplitude of 3.7 cm during one month after the earthquake. The hydrogeodynamic precursor detected in real time gave grounds for forecasting a highly probable strong earthquake at a distance of up to 350 km from wells E-1 within a month. This forecast was reported to the Kamchatka Branch of the Russian Expert Council (KB REC) on January 21, 2016. The Zhupanov­sky earthquake occurred on January 30, 2016, and its magnitude, time and location correlated with the prediction. The case of this earthquake shows that the Kamchatka Branch of the Federal Research Center ‘Geophysical Survey of RAS’ has the system of water level observations and data processing, which is capable of diagnosing (close to real time and retrospectively) different types of hydrogeoseismic variations in the water level in wells in case of strong seismic events, and detecting the hydrogeodynamic precursors of strong earthquakes.

Characterization of the karst hydrogeology of the Boone Formation in Big Creek Valley near Mt. Judea, Arkansas—documenting the close relation of groundwater and surface water

The Boone Formation has been generalized as a karst aquifer throughout northern Arkansas, although it is an impure limestone. Because the formation contains from 50 to 70 % insoluble chert, it is typically covered with a mantle of regolith, rocky clay, and soil which infills and masks its internal fast-flow pathways within the limestone facies. This paper describes continuous monitoring of precipitation, water levels in wells, and water levels in streams (stream stage) in Big Creek Valley upstream from its confluence with the Buffalo National River to characterize the nearly identical timing response of relevant components of the hydrologic budget and to clearly establish the karstic nature of this formation. Although the complete hydrographs of streams and wells are not identical in the study area, lag time between precipitation onset and water-level response in wells and streams is rapid and essentially indistinguishable from one another. The spikey nature of the stream hydrographs reflects low storage, high transmissivity, and rapid draining of the upper zones of the karst aquifer, whereas the longer-term, plateau-like draining in the lower zones reflects groundwater perching on chert layers that feed low-yield springs and seeps through lower storage and lower permeability flow paths. Groundwater drainage to thin terrace and alluvial deposits with intermediate hydraulic attributes overlying the Boone Formation also shows rapid drainage to Big Creek, consistent with karst hydrogeology, but with high precipitation peaks retarded by slower recession in the alluvial and terrace deposits as the stream peaks move downstream.

Large earthquakes create vertical permeability by breaching aquitards

AbstractHydrologic responses to earthquakes and their mechanisms have been widely studied. Some responses have been attributed to increases in the vertical permeability. However, basic questions remain: How do increases in the vertical permeability occur? How frequently do they occur? Is there a quantitative measure for detecting the occurrence of aquitard breaching? We try to answer these questions by examining data from a dense network of ∼50 monitoring stations of clustered wells in a sedimentary basin near the epicenter of the 1999 M7.6 Chi‐Chi earthquake in western Taiwan. While most stations show evidence that confined aquifers remained confined after the earthquake, about 10% of the stations show evidence of coseismic breaching of aquitards, creating vertical permeability as high as that of aquifers. The water levels in wells without evidence of coseismic breaching of aquitards show tidal responses similar to that of a confined aquifer before and after the earthquake. Those wells with evidence of coseismic breaching of aquitards, on the other hand, show distinctly different postseismic tidal response. Furthermore, the postseismic tidal response of different aquifers became strikingly similar, suggesting that the aquifers became hydraulically connected and the connection was maintained many months thereafter. Breaching of aquitards by large earthquakes has significant implications for a number of societal issues such as the safety of water resources, the security of underground waste repositories, and the production of oil and gas. The method demonstrated here may be used for detecting the occurrence of aquitard breaching by large earthquakes in other seismically active areas.

Groundwater qualitative prediction using artificial neural networks and support vector machine model case Study: Sirjan plain

Groundwater resources are one considered as one of the most common and important resources of drinking, agriculture and industry water. Due to the lowering of groundwater levels and its volatility, groundwater quality is of utmost importance. The aim of this study is to identify the predictive ability of artificial neural network of Multi-Layer Perceptron (MLP) and Support Vector Machine model and adaptive neuro-fuzzy inference system in which the quality of groundwater in Sirjan Plain has been predicted. A case study was conducted on the Sirjan Plain located in the city of Sirjan in Kerman province. For this purpose, the data of rainfall, the water level in wells and UTM coordinates of intended wells have been used as input combinations and qualitative parameters of the water of wells as output parameters. After initial processes such as normalization, for double-layer neural network, 85% of data were used for training and 15% for validation, and the same ration were applied to ANFIS and SVM. After reviewing the fitness statistical criteria such as correlation coefficient (R), and Root Mean Square Error (RMSE), it was observed that neural network presented an acceptable result compared to SVM and ANFIS models.

Water scarcity and oil palm expansion: social views and environmental processes

Merten, J., A. Röll, T. Guillaume, A. Meijide, S. Tarigan, H. Agusta, C. Dislich, C. Dittrich, H. Faust, D. Gunawan, J. Hein, . Hendrayanto, A. Knohl, Y. Kuzyakov, K. Wiegand, and D. Hölscher. 2016. Water scarcity and oil palm expansion: social views and environmental processes. Ecology and Society 21(2):5.http://dx.doi.org/10.5751/ES-08214-210205

Multiobjective fuzzy optimization for sustainable groundwater management using particle swarm optimization and analytic element method

Groundwater management involves conflicting objectives as maximization of discharge contradicts the criteria of minimum pumping cost and minimum piping cost. In addition, available data contains uncertainties such as market fluctuations, variations in water levels of wells and variations of ground water policies. A fuzzy model is to be evolved to tackle the uncertainties, and a multiobjective optimization is to be conducted to simultaneously satisfy the contradicting objectives. Towards this end, a multiobjective fuzzy optimization model is evolved. To get at the upper and lower bounds of the individual objectives, particle Swarm optimization (PSO) is adopted. The analytic element method (AEM) is employed to obtain the operating potentio metric head. In this study, a multiobjective fuzzy optimization model considering three conflicting objectives is developed using PSO and AEM methods for obtaining a sustainable groundwater management policy. The developed model is applied to a case study, and it is demonstrated that the compromise solution satisfies all the objectives with adequate levels of satisfaction. Sensitivity analysis is carried out by varying the parameters, and it is shown that the effect of any such variation is quite significant. Copyright (c) 2015 John Wiley & Sons, Ltd.

Aspectos Hidrodinâmicos, Balanço Hídrico e Simulação de Fluxo no Aquífero Costeiro de Itaipuaçu, Maricá – Rio de Janeiro, Brasil

This research was conducted in the coastal aquifer of Itaipuaçu district, Marica, Rio de Janeiro in Brazil. This is an aquifer of great importance for the region, as it is still the only autochthonous means of water supply for a growing population. The use of this water resource without control is a big problem, because quality can be impaired by contamination coming from the surface and, as a coastal aquifer, overexploitation can generate migration of saltwater / freshwater interface towards mainland and can salinize it. The paper aims to present the hydrodynamic characteristics of the shallow aquifer of the study area, by assessing local flow, flow parameters of the aquifer, acquisition and processing of meteorological data and water balance of the aquifer system, with the application of Visual Balan V.2.0 code. Other calculation methodologies were employed, as hydrometeorological simplified balance (Easybal v.4 computer code) and water balance with use of Darcy's Law. Wells were drilled in the shallow aquifer of the study area to assess local stratigraphy, and interference tests were performed to obtain physical parameters of the aquifer (permeability and storage coefficient). In situ measurements of water levels in wells were performed in the region to map the shallow aquifer head distribution. The data indicate a low hydraulic gradient and equipotential lines subparallel to the shoreline. Based on the hydraulic parameters, flow simulations were performed with the software Visual Modflow 4.2. The results obtained to date indicate a recharge of about 36% of the precipitation and hydraulic gradient less than 1%. Obtaining in situ parameters of the aquifer was crucial for the proper model fit and evaluation of the local aquifer properties.

Coseismic response of groundwater level in the Three Gorges well network and its relationship to aquifer parameters

The 12 May 2008 Ms 8.0 Wenchuan earthquake caused notable changes in the water levels of wells in the Three Gorges area. This work examines the relationship between these coseismic changes in water level and the changes in aquifer parameters. Three wells in the area with good responses to earth tide were chosen for analysis. Water-level data from February to June 2008 were used to calculate the aquifer transmissivity, permeability and specific storage of the rocks, and analyze the relationship between the coseismic responses of the wells and their aquifer parameters. The results show that the Wenchuan earthquake changed these parameters considerably, thereby controlling co- and postseismic variations of water level. The values of these parameters prior to the earthquake are linearly related with the amplitudes of coseismic variations in water level. The larger the aquifer transmissivity, the more remarkable the coseismic change in water level. During the earthquake, changes in aquifer parameters were found to be associated with coseismic variations in water level, with the larger changes occurring when the coseismic variation in water level was larger. The tectonic setting has a certain degree of influence on the co- and postseismic changes in water level. The permeability structures of the fault zone appear to determine the manner of coseismic variation in water level. Moreover, it seems that the water level in wells where groundwater converges more easily can recover faster following an earthquake. Insight from this study helps to improve understanding of the characteristics of water-level changes caused by earthquakes.

Impact of Groundwater Recharge Structures in Saurashtra and Kutch

This paper evaluates the impact of a large scale programme of construction of groundwater recharge structures by the Government of Gujarat in participation with local communities in Saurashtra and Kutch. There is significant positive impact on water level in wells, duration of time for which water is available, provision of both supplementary as well as protective irrigation services, increase in the number of hours during which water is pumped per day during both kharif and rabi seasons, increase in land under cultivation in the crop seasons, as well as improvements in cropping intensities.

Temporal pollution by nitrate (NO3), and discharge of springs in shallow crystalline aquifers: Case of Akok Ndoue catchment, Yaounde (Cameroon)

Less than 30% of households in Yaounde have direct access to pipe-borne water. It is important to generate a time series on quality and quantity of spring water, which is an alternative source of water. Accordingly, temporal variation of NO3 and dissolved oxygen (DO), lag time of springs recharge by rainfall, discharge of springs and annual discharge of water from the Akok-Ndoue catchment was evaluated. Eleven springs, 3 wells and 1 rain gauge were investigated for 24 months. Flow rate, electrical conductivity, water temperature, DO, pH, water level in wells, rainfall amount and major ions were measured monthly. Temporally, the months of March, April, September and October are when the springs and shallow wells are polluted by NO3. Spatially, springs at lower altitudes are also susceptible to NO3 pollution. Rainfall depths from 125 to 275 and >275 mm/month recharge springs after 1 to 2 months, and less than 1 month, respectively. Moreover, when rainfall amount is <100 mm, it takes about 2 months for the discharge of the springs to decrease to less than 0.2 l/s. The springs were of category 5-7 on the Meinzer’s classification scheme. Recharge was estimated at 50 mm/year and the springs showed a wide range of variability with discharge that decreased with increase in elevation. Key words: Springs, Spatio-temporal pollution, discharge, crystalline aquifer, Yaounde, Cameroon

Arsenic transport in irrigation water across rice-field soils in Bangladesh

Experiments were conducted to analyze processes impacting arsenic transport in irrigation water flowing over bare rice-field soils in Bangladesh. Dissolved concentrations of As, Fe, P, and Si varied over space and time, according to whether irrigation water was flowing or static. Initially, under flowing conditions, arsenic concentrations in irrigation water were below well-water levels and showed little spatial variability across fields. As flowing-water levels rose, arsenic concentrations were elevated at field inlets and decreased with distance across fields, but under subsequent static conditions, concentrations dropped and were less variable. Laboratory experiments revealed that over half of the initial well-water arsenic was removed from solution by oxidative interaction with other water-column components. Introduction of small quantities of soil further decreased arsenic concentrations in solution. At higher soil-solution ratios, however, soil contributed arsenic to solution via abiotic and biotic desorption. Collectively, these results suggest careful design is required for land-based arsenic-removal schemes.

Changes in permeability caused by transient stresses: Field observations, experiments, and mechanisms

Oscillations in stress, such as those created by earthquakes, can increase permeability and fluid mobility in geologic media. In natural systems, strain amplitudes as small as 10−6 can increase discharge in streams and springs, change the water level in wells, and enhance production from petroleum reservoirs. Enhanced permeability typically recovers to prestimulated values over a period of months to years. Mechanisms that can change permeability at such small stresses include unblocking pores, either by breaking up permeability‐limiting colloidal deposits or by mobilizing droplets and bubbles trapped in pores by capillary forces. The recovery time over which permeability returns to the prestimulated value is governed by the time to reblock pores, or for geochemical processes to seal pores. Monitoring permeability in geothermal systems where there is abundant seismicity, and the response of flow to local and regional earthquakes, would help test some of the proposed mechanisms and identify controls on permeability and its evolution.