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1
Chen, Yiming. "Aquifer storage and recovery in saline aquifers." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/52266.
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Aquifer storage and recovery (ASR) is a particular scheme of artificial recharge of groundwater by injecting fresh water into aquifers and subsequently recovering the stored water during times of peak demand or extended drought. In the era of combating climate change, ASR, as an effective means for water reuse and sustainable management of water resources in concert with the natural environment, represents a huge opportunity for climate change adaptation to mitigate water availability stress.The success of an ASR scheme is quantified by the recovery efficiency (RE), defined as the volume of stored water that can be recovered for supply purposes divided by the total volume injected. It is not uncommon that RE may be significantly lower than 100% because of the water quality changes as a consequence of the mixing between the injected water and native groundwater and the interaction between injected water and soil. Thus, the key of a successful ASR scheme is (1) to select appropriate aquifers and (2) to design optimal operational processes to build up a bubble of injected water with minimized negative impact from such mixing and interaction.
To achieve this, this thesis develops an integrated knowledge base with sound interdisciplinary science and understanding of the mixing processes under operational ASR management in aquifers with various hydrogeological conditions. Analytical and numerical modeling are conducted to improve the scientific understanding of mixing processes involved in ASR schemes and to provide specific technical guidance for improving ASR efficiency under complex hydrogeological conditions. (1) An efficient approach is developed to analytically evaluate solute transport in a horizontal radial flow field with a multistep pumping and examine the ASR performance in homogeneous, isotropic aquifer with advective and dispersive transport processes. (2) Numerical and analytical studies are conducted to investigate the efficiency of an ASR system in dual-domain aquifers with mass transfer limitations under various hydrogeological and operational conditions. Simple and effective relationships between transport parameters and ASR operational parameters are derived to quantify the effectiveness and ascertain the potential of ASR systems with mass transfer limitations.(3) Effects of hydrogeological and operational parameters on ASR efficiency are assessed in homogeneous/stratified, isotropic/anisotropic coastal aquifers. Effects of transverse dispersion are particularly investigated in such aquifers.(4) Finally, we test and study an innovative ASR scheme for improving the RE in brackish aquifers: injection through a fully-penetrated well and recovery through a partially-penetrated well.
2
Walter, Martin. "Explaining the emergence of transboundary groundwater management : the cases of Guaraní aquifer system, the Hueco and Mesilla Bolsón aquifers, and the Génévois aquifer." Paris, Institut d'études politiques, 2012. https://spire.sciencespo.fr/notice/2441/5rkqqmvrn4tl22s9mc41lidr0.
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Malgré la diversité de contributions concernant l’analyse des ressources hydriques et la multiplicité d’expériences de gestion de ces ressources, les eaux souterraines n’ont été incorporées dans l’agenda politique des relations internationales que très récemment. En ligne avec les recherches dédiées à la compréhension des défis associés à la gestion des eaux et à l’émergence des mécanismes de régulation pour la gestion environnementale, ce travail examine la création de mécanismes pour la gestion conjointe des eaux souterraines transfrontalières. Pour ce faire, il essaye de répondre une question relativement simple : quels facteurs ont été déterminants pour l’émergence et la mise en œuvre de mécanismes de gestion conjointe des eaux souterraines ? A partir d’une révision de la littérature disponible et de l’étude comparée de trois cas, cette recherche a trouvé que dans la reconnaissance et la formulation des problèmes des eaux souterraines interagissent toujours trois types de facteur : les usages de l’eau souterraine, les caractéristiques hydrogéologiques des aquifères et la valeur sociale attribuée à la disponibilité éco-systémique des ressources. Cette recherche a trouvé d’ailleurs que la simple existence de problèmes associés à la disponibilité des ressources ne pousse pas automatiquement à la création des mécanismes de gestion. Ces derniers, qui peuvent être coordonnés ou unilatéraux, découlent d’une articulation d’éléments systémiques et socio-institutionnelsDespite the diversity of the contributions to the analysis of water resources and the myriad of water management experiences, transboundary groundwaters have only relatively recently entered the international political agenda. In line with research dedicated to understanding the challenges associated with the management of water resources and the creation of environmental regulatory frameworks, this dissertation examines the emergence of mechanisms for the management of transboundary groundwater resources. In doing so, it makes a seemingly straightforward inquiry. What are the factors that trigger the emergence and implementation of groundwater management mechanisms? Drawing from the review of the literature and the comparative analysis of three cases of transboundary groundwater management, this research finds that the recognition of groundwater problems is determined by the interplay of three factors: the uses of groundwater, the features of the hydrogeological resources, and the social valuation of the eco-system services provided by the resources. In addition, it suggests that groundwater problems are not sufficient to explain the nature of the mechanisms employed for the management of the resources. It argues that management mechanisms, which may be coordinated or unilateral, result from the configuration of both systemic and socio-institutional factors
3
Wendelborn, Anke. "Zinc and copper behaviour during stormwater aquifer storage and recovery in sandy aquifers." Monash University. Faculty of Engineering. Department of Civil Engineering, Institute for Sustainable Water Resources, 2008. http://arrow.monash.edu.au/hdl/1959.1/68715.
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In the light of increasing demand and diminishing supplies a sustainable urban water management for Melbourne and other cities will need to include water recycling and reuse of reclaimed water and stormwater. One key issue in stormwater reuse is the need for storage between times of collection until times of demand. Aquifer storage and recovery (ASR) would be a valuable option as it has limited space requirements and restricts loss from evaporation. However, stormwater commonly contains elevated levels of heavy metals, of which Zn and Cu are the most mobile. Stormwater also contains suspended solids, organic carbon, oxygen and nutrients, which influence the behaviour of injected metals and induce geochemical changes in the aquifer. While stormwater ASR has been practiced in limestone aquifers in South Australia, field data for sandy aquifers, which are more prevalent around Melbourne, are very limited. Risk assessment regarding the potential impact of stormwater ASR on the quality of the aquifer and groundwater resources in sandy aquifer is therefore necessary. After a characterisation of stormwater from different Melbourne catchments confirmed comparatively high concentrations of Zn and Cu in stormwater, three siliceous aquifer sediments were used in a series of batch sorption experiments as well as column experiments imitating one ASR cycle to assess the impact of different parameters on Zn and Cu behaviour. The reactive geochemical transport model PHT3D was then modified to simulate experimental results with the outlook that it could be used as a predictive tool for long term evaluation. The study showed that Zn adsorption was limited and desorption of large fractions occurred, indicating that injected amounts of Zn are mobile and would mainly be recovered. In contrast, Cu adsorption was higher and desorption was limited, indicating that injected amounts of Cu would mainly accumulate in the aquifer. The release of metals was triggered by reduction in pH, increase in ionic strength and particle mobilisation. Metal concentrations were also increased after storage phases, while minor sediment constituents, especially organic matter, significantly reduce metal mobility. The different role of dissolved and solid organic carbon is critical in understanding Cu behaviour during stormwater ASR. Pretreatment of stormwater to reduce the injection of colloids, organic carbon and metals are recommended to limit metal accumulation in the subsurface. Monitoring of water quality throughout the ASR cycle would be encouraged to validate the current findings with field data. Special attention should be paid to backflushed water quality to ensure correct disposal.
4
Pindoria-Nandha, Mital. "Planning an aquifer storage and recovery scheme in the Sherwood Sandstone aquifer." Thesis, Cranfield University, 2016. http://dspace.lib.cranfield.ac.uk/handle/1826/11313.
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Aquifer Storage and Recovery (ASR) involves the injection of water into an aquifer for subsequent recovery from the same well. Whilst ASR provides a competitive alternative to reservoir storage, a lack of precedence of successful schemes and uncertainties with respect to regulatory requirements, and abstracted water quality and quantity have limited its implementation in the UK. The ambition of this research is to improve understanding of these impediments with particular reference to the Sherwood Sandstone aquifer. Drawing on existing project review and risk management approaches, a decision support tool to help scheme designers scope ASR scheme potential and challenges was developed and tested. The tool provides practitioners with a systematic method for early stage evaluation of ASR schemes with testing confirming broad value and alignment with business processes. Limitations on the recovery of recharged water was investigated through a critical literature review on clogging with geochemical, biological, physical and gaseous binding processes identified as the most likely mechanisms to impact an ASR scheme in this aquifer. Water quality changes during storage and the impact of storage period on recovered water quality were investigated in the laboratory using ASR simulating columns, with storage times of 15, 20, 30 and 60 days. Water quality improvements such as biodegradation of disinfection by-products, denitrification and sulphate reduction were observed. However recovered water quality deteriorated with respect to iron, arsenic, manganese, total organic carbon and nickel. These results, together with the review of regulations conducted as part of decision support tool development, suggest that the current interpretation of the Water Framework Directive requirements is overly restrictive and is deterring wider implementation of ASR in the UK. Conclusions focus on the need for a more appropriate approach to regulating ASR schemes, in particular, one which adopts a risk based approach to determining water quality standards.
5
Heckel, Kyle Christopher. "PETROLEUM CONTAMINATED AQUIFER REMEDIATION." Thesis, The University of Arizona, 2009. http://hdl.handle.net/10150/192479.
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6
Williams, David G. "Whole aquifer system management: the northeast floridan aquifer system under an interstate compact." Thesis, Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/30907.
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7
Wright, Timothy Edwin James. "Predicting the applicability of aquifer storage recovery (ASR) in the UK chalk aquifer." Thesis, University College London (University of London), 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.405796.
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8
Sun, Dongmin. "Aquitard control of stream-aquifer interaction and flow to a horizontal well in coastal aquifers." Diss., Texas A&M University, 2005. http://hdl.handle.net/1969.1/4740.
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This dissertation is composed of three parts of major contributions: In Chapter II, we developed a new conceptual model and derived a new semi-analytical model for flow to a horizontal well beneath a water reservoir. Instead of treating the leakage from aquitard as a source term inside the aquifer which is called HantushâÂÂs assumption (1964), we linked flows in aquitard and aquifer by the idea of continuity of flux and drawdown. The result in this chapter is compared with that of Zhan and Park in 2003 which HantushâÂÂs assumption is adopted at various hydraulic and well configurations. It shows that HantushâÂÂs assumption becomes inaccurate in regions where vertical velocity components are significant. In Chapter III, we deal with the interaction of an aquifer with two parallel surface water bodies such as two streams or canals. In this chapter, new closed-form analytical and semi-analytical solutions are acquired for the pumping induced dynamic interaction between two streams and ground water for two different cases. In the first case, the sediment layers separating the streams from the aquifer ground water do not exist. In the second case, the two low permeable layers are considered. The effect of aquitard and water right competition is addressed in this chapter. This model can be used for interpreting and deriving hydrologic parameters of aquitard and aquifer when pumping occurs between two channels. It can also be used to predict stream depletion which is essential for water management and ecology conservation. In Chapter IV, we investigated the three dimensional upconing due to a finite-length of horizontal well and its critical conditions. The results are compared with those of vertical wells. The critical condition which includes the critical rise and the critical time at a certain pumping rate depends on the well length, the initial interface location, the well location, and the pumping rate. Our results show that horizontal well might be a better tool for coastal groundwater resources development. In real field applications, installing long wells as shallow as possible is always desirable for sustaining long periods of pumping with significant rates.
9
Khater, A. M. R. "Management of stream-aquifer systems." Thesis, University of Southampton, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380176.
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10
Elobaid, Elnaiem Ali. "Aquifer investigations in north Qatar." Thesis, University of Bedfordshire, 2000. http://hdl.handle.net/10547/606074.
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The purpose of this study was to investigate the levels and quality of groundwater in a farming area to the north of Doha, the capital of the State of Qatar. Two rows of about five wells were selected, the lines being more or less parallel to each other, about 30 km apart, running for 45 km inland from the east coast. Vertical electrical sounding surveys were undertaken and groundwater samples were taken from these wells in winter and in summer. The water was chemically analysed, and the results formed the basis for a hydrogeochemical modelling exercise. The results of the geophysical and geochemical surveys indicate that there is a seasonal vertical and lateral migration of the fresh water/salt water interface in winter before the rainfall replenishes the groundwater aquifers. The geochemistry of the groundwater indicate that there is a gradual decrease of cations and anions, particularly Na+, cr, S04, and HC03-, together with a decrease in conductivity CEC), total dissolved solids (TDS) and sodium absorption ratio (SAR) from the coast inland. There is an upconing which brings the saline water to the surface near the middle of the southern profile in both seasons. In both profiles the fresh water/salt water interface migrates inland due to the excessive extraction of fresh water from the wells.
11
Zhang, Zhihui. "Quantitative characterization of aquifer heterogeneity and simulation of contaminant transport in a solvent-contaminated aquifer." Diss., The University of Arizona, 1999. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_1999_148_sip1_w.pdf&type=application/pdf.
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Florea, Lee John. "The karst of west-central Florida." [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001783.
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13
Rotzoll, Kolja. "Hydraulic Parameter Estimation Using Aquifer Tests, Specific Capacity, Ocean Tides, and Wave Setup for Hawai'i Aquifers." Thesis, Water Resources Research Center, University of Hawaii at Manoa, 2007. http://hdl.handle.net/10125/22265.
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The islands of Hawaii face increasing ground-water demands due to population growth in the last decades. Analytical and numerical models are essential tools for managing sustainable ground-water resources. The models require estimates of hydraulic properties, such as hydraulic conductivity and storage parameters. Four methods were evaluated to estimate hydraulic properties for basalts on the island of Maui. First, unconventional step-drawdown tests were evaluated. The results compare favorably with those from classical aquifer tests with a correlation of 0.81. Hydraulic conductivity is log-normally distributed and ranges from 1 to 2,500 m/d with a geometric mean of 276 m/d and a median of 370 m/d. The second approach developed a simplified parameter-estimation scheme through an empirical relationship between specific capacity and hydraulic parameters that utilized Hawaii's state well database. For Maui's basalts, the analysis yields a geometric-mean and median hydraulic conductivity of 423 and 493 m/d, respectively. Results from aquifer tests and specific-capacity relationships were used to generate island-wide hydraulic-conductivity maps using kriging. The maps are expected to be of great benefit in absence of site-specific field assessments. In the third approach, ocean-tide responses in the central Maui aquifer were used to estimate an effective hydraulic diffusivity of 2.3 x 10^7 m^2/d. The position of the study area necessitated refining the existing analytical solution that considers asynchronous and asymmetric tidal influence from two sides in an aquifer. Finally, measured ground-water responses to wave setup were used to estimate hydraulic parameters. Setup responses were significant as far as 5 km inland and dominated barometric-pressure effects during times of energetic swell events. The effective diffusivity estimated from setup was 2.3 x 10^7 m^2/d, matching that based on tides. Additionally, simple numerical ground-water flow models were developed to assess the accuracy of results from analytical solutions for step-drawdown tests, dual-tides and wave setup, and to evaluate sediment-damping effects on tidal propagation. The estimated mean hydraulic conductivities of the four methods range between 300 and 500 m/d for basalts in Maui. The results of different methods are consistent among each other and match previous estimates for basalts.USGS Pacific Island Water Science Center
14
Damico, James Ralph. "Geostatistical Characterization of Heterogeneity in the Aberjona River Aquifer, Woburn, Massachusetts." Wright State University / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=wright1166544810.
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Martin, Gregory D. "Aquifer underground pumped hydroelectric energy storage." Connect to online resource, 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1447687.
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Jones, Lawson Elliott. "A real-time aquifer management tool." Thesis, Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/20743.
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Wright, Winfield G. "Modeling karst aquifer response to rainfall." Thesis, Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/76043.
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A finite-element model (HYDMATCH) uses spring hydrograph discharge data to generate a linear regression relation between fracture conductivity and potential gradient in a karst aquifer system. Rainfall excess in the form of potential energy from sinkhole sub-basins is input to element nodes and routed through a one-dimensional finite-element mesh to the karst spring represented by the last node in the finite element mesh. A fracture-flow equation derived from the Navier-Stokes equation uses fracture conductivities from the regression equation and potential gradient in the last element of the mesh to determine discharge at the spring.
Discharge hydrograph data from Nininger spring, located in Roanoke, Virginia, was used to test the performance of the model. Excess from a one-half inch rain was introduced into sinkhole nodes and the regression equation generated by matching discharges from the known hydrograph for the one-half inch rainfall. New rainfall excess data from a one-inch rainfall was input to the sinkhole nodes and routed through the finite-element mesh. The spring hydrograph for the one-inch rainfall was calculated using the regression equation which was determined previously. Comparison of the generated hydrograph for the one-inch rainfall to a known hydrograph for a one-inch rainfall shows similar shapes and discharge values.
Areas in need of improvement in order to accurately model ground-water flow in karst aquifers are a reliable estimate of rainfall excess, a better estimation of baseflow and antecedent aquifer conditions, and the knowledge of the karst aquifer catchment boundaries. Models of this type may then be useful to predict flood discharges and contaminant travel times in karst aquifers.Master of Engineering
18
Schmitt, Elizabeth Marie. "Arizona's Approach to Aquifer Protection Regulation." Thesis, The University of Arizona, 2014. http://hdl.handle.net/10150/555564.
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Arizona’s approach to aquifer and groundwater protection is ax-ante and four tied. On the federal level, pesticides are required to be registered under the Federal Insecticide, Fungicide, and Rodenticide Act. The Arizona Department of Water Resources registers the use of these pesticides in Arizona. The Aquifer Protection Plan Program distributes permits to allow pollutants to be discharged into the water supply in certain quantities. Lastly, the Safe Drinking Water Act regulates the amount of contaminants that can be permitted in drinking water. This paper evaluates each of these four approaches to aquifer protection regulation, including the application of the regulations.
19
Forghani, Ali. "Simulation and Optimization Models to Evaluate Performance of Aquifer Storage and Recovery Wells in Fresh Water Aquifers." DigitalCommons@USU, 2018. https://digitalcommons.usu.edu/etd/6933.
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Aquifer storage and recovery (ASR) involves artificially recharging an aquifer through well(s) using surplus water for later recovery in high-demand months. The operators of the studied ASR system developed the system as a means of receiving additional water rights to supplement their pre-existing water rights for extraction in dry months. However, the region’s water regulators define the performance of this ASR system as the amount of the injected water that is recoverable from the same wells during extraction periods. The study proposes recovery effectiveness (REN) as the performance index of this ASR system. REN equals the injectate proportion that the same wells can recover. Quantifying the system's achievable REN is required to determine the amount of the additional water rights. Similarity between the injected water and native groundwater, however, prevents an accurate REN estimation using on-field techniques. This necessitates the use of computer modeling for estimating REN in this system. The study employs simulation, statistical, and optimization models to quantify and maximize REN in the studied ASR system in Utah.
20
Richmond, Nicole L. "THE CARBON BUDGET OF A SHALLOW, TROPICAL AQUIFER: SOURCES, SINKS, AND PROCESSES." Oxford, Ohio : Miami University, 2003. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=miami1070212062.
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Thesis (M.S.)--Miami University, Dept. of Geology, 2003.Title from first page of PDF document. Document formatted into pages; contains vii, 127 p. : ill. Includes bibliographical references (p. 108-113).
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Altinors, Adnan Altay. "Non-darcian Flow In A Fractured Aquifer." Phd thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12606386/index.pdf.
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Non-Darcian flow in a finite fractured aquifer is studied in this thesis. A stream bounds the aquifer at one side and an impervious stratum at the other. The aquifer consists of fractures capable of transmitting water rapidly and porous blocks which mainly store water. Unsteady flow in the aquifer due to a sudden or a gradual rise in the stream level is analysed by the double-porosity conceptual model. Governing equations for the flow in fractures and blocks are developed using the continuity equation. The fluid velocity in fractures is often too high for the linear Darcian flow so that the governing equation for fracture flow is modified by Forcheimer&rsquos equation which incorporates a nonlinear term. Governing equations are coupled by an interaction term that controls the quasi-steady state fracture-block interflow. Governing equations are solved numerically by the Crank-Nicolson implicit scheme. The numerical results are compared to the analytical results for the same problem which assumes Darcian flow both in fractures and blocks. Numerical and analytical solutions give same results when Reynold&rsquo
s number is less than 0.1. The effect of non-linearity on the flow appears when Reynold&rsquo
s number is greater than 0.1. The larger the piezometric head gradient, the higher the flow rate and, thus, higher the non-linearity is. The effect of aquifer parameters on the flow is also investigated. The proposed model and its numerical solution is a unique application of non-linear flow models to the fractured aquifers. It can be used in predicting water levels in fractured aquifers and evaluating time dependent flow rates in the analysis of recession hydrographs.
22
Xu, Xiuyuan. "Interaction of Chemical Oxidants with Aquifer Materials." Thesis, University of Waterloo, 2006. http://hdl.handle.net/10012/2891.
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In situ chemical oxidation (ISCO) is a leading-edge technology for soil and groundwater remediation, and involves injecting a chemical oxidant (e. g. , permanganate, hydrogen peroxide, or persulfate) into the subsurface to deplete contaminant mass through oxidation. Since the delivery of the chosen oxidant to the target treatment zone must occur in situ, the interaction between the injected oxidant and the aquifer material is a key controlling factor for a successful ISCO application. While many published ISCO studies have focused on the interaction between an oxidant and target contaminants, many questions still remain on the interaction between a potential oxidant and the aquifer material. Through a series of bench-scale experiments with aquifer materials collected from 10 sites throughout North America, the research presented in this thesis provides insight into the interaction between these aquifer materials and two widely used ISCO oxidants; permanganate and hydrogen peroxide. The investigation into the interaction between aquifer materials and permanganate consisted of three series of bench-scale experiments: (1) long-term batch experiments which were used to investigate permanganate consumption in response to fundamental geochemical properties of the aquifer materials, (2) short-term batch experiments which were designed to yield kinetic data that describe the behavior of permanganate in the presence of various aquifer materials, and (3) column experiments which were used to investigate permanganate transport in a system that mimics the subsurface environment. The long-term experiments which involved more than 180 batch reactors monitored for ~300 days showed that the unproductive permanganate consumption by aquifer materials or natural oxidant demand (NOD) is strongly affected by the initial permanganate concentration, permanganate to solid mass ratio, and the reductive components associated with each aquifer material. This consumption cannot be represented by an instantaneous reaction process but is kinetically controlled by at least a fast and slow reactive component. Accordingly, an empirical expression for permanganate NOD in terms of aquifer material properties, and a hypothetical kinetic model consisting of two reaction components were developed. In addition, a fast and economical permanganate NOD estimation procedure based on a permanganate COD test was developed and tested. The investigation into short-term permanganate consumption (time scale of hours) was based on the theoretical derivation of the stoichiometric reaction of permanganate with bulk aquifer material reductive components, and consisted of excess permanganate mass experiments and excess aquifer material mass experiments. The results demonstrated that permanganate consumption by aquifer materials can be characterized by a very fast reaction on the order of minutes to hours, confirming the existence of the fast reaction component of the hypothetical kinetic model used to describe the long-term permanganate NOD observations. A typical experimental column trial consisted of flushing an aquifer-material packed column with the permanganate source solution until sufficient permanganate breakthrough was observed. The permanganate column results indicated the presence of a fast and slow consumption rate consistent with the long-term batch test data, and an intermediate consumption rate affecting the shape of the rising limb of the breakthrough curve. Finally, a comparison of the experimental results between batch and column systems indicated that permanganate NOD was significantly overestimated by the batch experiments; however, permanganate consumption displayed some similarity between the batch and column systems and hence an empirical expression was developed to predict permanganate consumption in physically representative column systems from batch reactor data.
The interaction between hydrogen peroxide and aquifer materials was also investigated with both batch and column experiments. A series of batch experiments consisting of a mixture of 2% hydrogen peroxide and 15 g of aquifer materials was used to capture the overall hydrogen peroxide behavior in the presence of various aquifer materials. The results indicated that the decomposition of hydrogen peroxide in the presence of various aquifer materials followed a first-order rate law, and was strongly affected by the content of amorphous transition metals (i. e. , Fe and Mn). Although hydrogen peroxide decomposition is related to the total organic carbon (TOC) content of natural aquifer materials, the results from a two-week long exposure to hydrogen peroxide suggests that not all forms of natural organic matter contributed to this decomposition. A multiple linear regression analysis was used to generate predictive relationships to estimate hydrogen peroxide decomposition rate coefficients based on various aquifer material properties. The enhanced stability of hydrogen peroxide was investigated under six scenarios with the addition of chelating reagents. The impact of a new green chelating reagent, S,S'-ethylenediaminedisuccinate (EDDS), on the stability of hydrogen peroxide in the presence of aquifer materials was experimentally examined and compared to that of the traditional and widely used chelating reagent, Ethylenediaminetetraacetic (EDTA). The results demonstrated that EDDS was able to significantly increase the stability of hydrogen peroxide, especially for aquifer materials with low TOC contents and/or high dissolvable Fe and Mn contents. Finally, to complement and expand the findings from the batch experiments, column experiments were conducted with aquifer materials from five representative sites. Each column was flushed with two types of source solutions (with or without EDDS addition) at two flow rates. The column experiments showed that the use of EDDS resulted in an earlier breakthrough and a higher stable concentration of hydrogen peroxide relative to the case without the addition of EDDS. The hydrogen peroxide decomposition rate coefficients generated from the column data were significantly higher than those generated from the batch test data and no correlation between hydrogen peroxide decomposition coefficients obtained from column and batch experiments was observed. Based on the column experimental results, a one-dimensional transport model was also calibrated to capture the hydrogen peroxide breakthrough process.
Data from bench-scale tests are routinely used to support both ISCO design and site screening, and therefore the findings from this study can be used as guidance on the utility of these tests to generate reliable and useful information. In general, the behavior of both permanganate and hydrogen peroxide in the presence of aquifer materials in batch and the column systems clearly indicates that the use of batch test data for ISCO system design is questionable since column experiments are believed to mimic in situ conditions better since column systems provide more realistic aquifer material contact. Thus the scaling relationships developed in this study provide meaningful tools to transfer information obtained from batch systems, which are widely employed in most bench-scale studies, to column systems.
23
Cartmell, E. "Aquifer denitrification : an experimental and modelling evaluation." Thesis, Imperial College London, 1997. http://hdl.handle.net/10044/1/7769.
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Reid, Brian. "Energy Flow in a Floodplain Aquifer Ecosystem." The University of Montana, 2007. http://etd.lib.umt.edu/theses/available/etd-05232007-165824/.
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We developed an energy budget to identify energy sources for the invertebrate community of a large 20 km2 floodplain aquifer, based on biomass distributions, organismal respirometry, in situ community respiration, mesocosm and microcosm experiments, stable isotopes and invertebrate gut contents. The invertebrate respiration scaling exponent was 0.474 (+/- 0.068, 95% CI) across six orders in body mass, which is significantly lower than the ¾ power scaling predicted by metabolic theory. Invertebrate production was dominated by copepods (Diacyclops, Acanthocyclops, Bryocamptus), Stygobromus amphipods, and amphibiont stoneflies, and ranged from 26.9 to 4200 mg C/m3 sediment/year. Production and density showed a U-shaped response to dissolved oxygen (high production at both low and high oxygen concentrations). Production declined exponentially with depth for most sites, but at sites with orthograde oxygen profiles there was an exponential increase at the oxycline. Aerobic microbial community production ranged from 1210 to 2020 mg C/m3 sediment/year, also showing a U-shaped response to oxygen. System respiratory quotient (RQ) ranged from ≈ 0 to 9.5, indicating a significant contribution of anaerobic production to system energy flow. We documented multiple lines of evidence for DOC (soil, river) and buried POM carbon sources, however POM was by far the largest carbon reservoir in the aquifer at ≈ 108 (to 1010) mg C/ m3 sediment. Energy from POM breakdown was the only source sufficient to explain microbial and invertebrate production. Carbon stable isotope signatures showed strong levels of depletion for invertebrates (δ13C -25 to -70). These results suggest a significant anaerobic subsidy of aerobic food webs in the subsurface, and a potential methane subsidy of 10% to 99% of invertebrate energy flow. Oxygen showed high, non-random, spatial and temporal variation across the aquifer, with a large scale decline in oxygen along the axis of the floodplain, and distinct hotspots of low oxygen. Low oxygen hotspots corresponded with migration of stonefly nymphs 100s of meters into the aquifer. The U-shaped responses and biogeochemical trends suggest a major threshold at bulk oxygen concentrations of 3-5 mg/l. Collectively, these findings indicate the role of dissolved oxygen as a key variable in groundwater ecosystems.
25
Rivett, Michael Owen. "The organic contamination of the Birmingham aquifer." Thesis, University of Birmingham, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.491197.
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Tunison, Douglas Irvin. "Streamline simulation of surfactant enhanced aquifer remediation." Thesis, Monterey, California. Naval Postgraduate School, 1996. http://hdl.handle.net/10945/31159.
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Nonaqueous Phase Liquids (NAPLs) are a recognized source of groundwater contamination. Surfactant Enhanced Aquifer Remediation (SEAR) shows promise in increasing the efficiency and effectiveness over traditional 'pump and treat' NAPL remediation processes. Laboratory results are not always consistent with the effects observed in field applications because of the complex interactions that occur in the subsurface. Mathematical modeling is required to enable accurate prediction and understanding of SEAR.
27
Hard, David William. "Microbial nitrogen transformations in a chalk aquifer." Thesis, Queen's University Belfast, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317081.
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Wu, Cheng-Mau, Tian-Chyi J. Yeh, Tim Hau Lee, Nein-Sheng Hsu, Chu-Hui Chen, and Albert Folch Sancho. "Traditional Aquifer Tests: Comparing Apples to Oranges?" Department of Hydrology and Water Resources, University of Arizona (Tucson, AZ), 2004. http://hdl.handle.net/10150/615770.
Full textAbstract:
Traditional analysis of aquifer tests uses the observed hydrograph at one well caused
by pumping at another well for estimating transmissivity and storage coefficient of an
aquifer. The analysis relies on Theis' or Jacob's approximate solution, which assumes
aquifer homogeneity. Aquifers are inherently heterogeneous at different scales. If the
observation well taps into a low permeability zone while the pumping well is located in a
high permeable zone, the resulting situation contradicts the homogeneity assumption
embedded in the traditional analysis. As a result, a practical but important question we
ask: What do we derive from the traditional analysis?
Using numerical experiments in synthetic aquifers, we answer this question.
Results of the experiments indicate that the effective transmissivity, Teff , and storage
coefficient, Seff , values vary with time, as well as the principal directions of the
transmissivity, but both values approach their geometric means of the aquifer at large
times. Analysis of the estimated transmissivity (T) and storage coefficient (S ) using well
hydrographs from a single observation well shows that at early times, both the estimated
T and S values vary with time. At late times, both estimates approach local averages
near the observation well. The T value approaches but does not equal Teff , representing
an average value over a broad area in the vicinity of the observation well while the S value converges to the value dominated by the storage coefficient near the
observation wells (i.e., its average area is much smaller than that of the t value).
29
Kostarelos, Konstantinos. "Surfactant enhanced aquifer remediation at neutral buoyancy /." Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.
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Jazayeri, Shoushtari Seyed Mohammad Hossein. "Groundwater Dynamics in a Sandy Unconfined Aquifer." Thesis, Griffith University, 2016. http://hdl.handle.net/10072/367171.
Full textAbstract:
Groundwater dynamics in a sandy unconfined aquifer have been investigated through laboratory experiments and numerical modelling. The laboratory experiments on the propagation of groundwater waves have yielded new insights into underlying physics. Numerical models have been developed to consider some aspects of groundwater dynamics such as the influence of seepage face and meniscuses formation, hysteresis effects, unsaturated flow dynamics, and porous media deformation. The laboratory data has then been used to verify numerical models and to examine their prediction capabilities.
New laboratory data from sand flume experiments for an idealized coastal aquifer forced by a simple harmonic forcing across a vertical boundary provided detailed measurements of the piezometric head very close to the interface. The data helped to consider the processes occurring near the boundary condition, particularly with respect to meniscus and seepage face formation during the falling tide. A numerical solution of the Richards’ equation was developed to model the influence of seepage face formation and meniscus suction and was evaluated against the data. The model-data comparisons
show good agreement with the pore pressure behavior high above the water table, but are sensitive to the choice of moisture retention parameters in the model.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Engineering
Science, Environment, Engineering and Technology
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Rabjohns, Kelley. "Impact of Aquifer Heterogeneity on Geomicrobial Kinetics." Thesis, University of Oregon, 2013. http://hdl.handle.net/1794/13270.
Full textAbstract:
Rates of microbial reactions are important in understanding groundwater chemistry and bioremediation. In aquifers, microbial rates depend on physicochemical and biological factors and also on how groundwater transport impacts microbial reactions at pore-scale. I numerically simulate microbial acetate consumption in a porous medium, focusing on how physical heterogeneity of the medium impacts the rates. My model is a 3-D cube, which represents a portion of a sandy aquifer. Acetate is supplied by groundwater flow through the cube, and microbes live on randomly distributed grain surfaces by oxidizing acetate. I simulated microbial acetate oxidation under a range of groundwater velocity, acetate concentrations, spatial heterogeneity, and other physicochemical conditions. The results demonstrate a significant gap in microbial kinetics between the pore-scale and continuum model. Specifically, microbial rates are larger in porous media of greater heterogeneity. For this reason, I propose that microbial parameters should not be applied directly to field-scale biogeochemical modeling.
32
Höyng, Dominik [Verfasser], and Peter [Akademischer Betreuer] Grathwohl. "Development and Modelling of a High-Resolution Aquifer Analog in the Guarani Aquifer (Brazil) / Dominik Höyng ; Betreuer: Peter Grathwohl." Tübingen : Universitätsbibliothek Tübingen, 2014. http://d-nb.info/1196802580/34.
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Trein, Heinz Alfredo [UNESP]. "A implicação antrópica na qualidade dos recursos hídricos subterrâneos da bacia hidrográfica do rio Urussanga - SC." Universidade Estadual Paulista (UNESP), 2008. http://hdl.handle.net/11449/102930.
Full textAbstract:
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trein_ha_dr_rcla.pdf: 8906165 bytes, checksum: fc8702e41d7ad5d1bec2ac761da62f6f (MD5)Esta tese apresenta os resultados dos estudos geológicos, hidrogeológicos, hidroquímicos, das fontes de poluição e do cadastramento de fontes de água subterrânea da área correspondente à bacia hidrográfica do rio Urussanga, Estado de Santa Catarina. A Bacia do Rio Urussanga apresenta uma rede de drenagem de 1064 km de extensão, abrangendo uma área de 580 km² com densidade média de drenagem de 1,83 (km/km2), e é formada pela junção dos rios Carvão e Maior. e outros tributários, destacando-se os seguintes rios: América, Caeté, Vermelho, Cocal, Ronco D´Água, Três Ribeirões, Cocalzinho, Ribeirão da Areia, entre outros. No mapeamento hidrogeológico foram identificados 11 sistemas aqüíferos, sendo 4 relacionados às rochas sedimentares gonduânicas, 1 aos sedimentos quaternários pleistocênicos, 1 relacionado às rochas basálticas cretáceas, 4 relacionados as formações sedimentares paleozóicas e um relacionado aos granitos neoproterozóicos. As atividades de mineração e de beneficiamento do carvão, as atividades industriais, a falta de rede de canalização e de tratamento de esgoto em todos os municípios e a utilização de adubos e defensivos agrícolas nas áreas cultivadas estão entre os principais fatores responsáveis pela contaminação dos recursos hídricos, degradação do solo e, conseqüentemente, pelo comprometimento ambiental de grande parte da área desta bacia hidrográfica.
This work presents the results regarding the geological, hydrogeological and hydrochemical surveys carried out in the area of Urussanga Hydrographic Basin. It also shows the data related to the pollution sources and the number of groundwater explotation spots in the referred basin. The Urussanga Hydrographic Basin has na drainage extension of 1064 km , covering 580 km² in área with a average drainage density of 1,83 (km/km2).It is formed by the junction of the rivers Carvão and Maior. Other trybutaries are also important: América, Caeté, Vermelho, Cocal, Ronco D´Água, Três Ribeirões, Cocalzinho, Ribeirão da Areia, between others little more. Regarding the structural aspects, we have concluded that the most important elements are the faults. The results off physic-chemical analysis of groundwater carried out along this study and in previous works have given us the hydrochemical classification of the different aquifer systems present in this basin.. Coal mining and treatment activities as well as industrial activities, the lack of drainage, the use of fertilizers and pesticides in the crops are the main responsible factors for water ressources contamination and soil degradation in this area. As a consequence, a large portion of the Urussanga Hydrographic Basin is in a bad environmental situation.
34
Matengu, Brian Munihango. "Groundwater assessment and sustainable management of the coastal alluvial aquifers in Namib Desert, Namibia: Omdel Aquifer as case study." University of Western Cape, 2020. http://hdl.handle.net/11394/7852.
Full textAbstract:
Philosophiae Doctor - PhDThe study addressed the groundwater assessment and sustainable management of the coastal alluvial aquifers in Namib Desert, the Omaruru River Delta Aquifer (Omdel Aquifer) was used as a case study. Sustainable utilization of groundwater in parts of hyper-arid Sub-Saharan Africa, like the Namib Desert, is always a challenge due to lack of resources and data. Understanding of hydrogeological characteristics of the Omaruru Delta Aquifer System is a pre-requisite for the management of groundwater supply in the Central Namib area (Namib Desert). For the Omdel Aquifer in the Omaruru catchment, Namibia, issues to investigate include the lack of information on the geology and hydrogeological setting, the hydraulic properties and geometry of the aquifer at the inflow and outflow sections, groundwater recharge conditions upstream of the aquifer, and the impact of artificial recharge.
35
Currens, Benjamin J. "DEUTERIUM AND OXYGEN-18 DIFFUSION IN A CONFINED AQUIFER: A NUMERICAL MODEL OF STABLE ISOTOPE DIFFUSION ACROSS AQUITARD-AQUIFER BOUNDARIES." UKnowledge, 2016. http://uknowledge.uky.edu/ees_etds/40.
Full textAbstract:
The stable isotopes 2H and 18O, combined with noble gases and radioisotopes (e.g., 3H, 14C, 36Cl), are used to infer groundwater age and climate during recharge. Flow regimes within low-velocity flowpaths and long residence times could allow an aquitard-aquifer diffusive flux to alter isotope abundance. Consequently, the diffusion of isotopes (e.g., 14C, 2H and 18O) between aquifers and confining layers needs to be considered in such conditions. In this study, COMSOL Multiphysics was used to determine if diffusion of 18O (and 2H by proxy) from a bounding aquitard could explain observed downgradient enrichment of 2H and 18O within a regional aquifer. Using the geologic and hydraulic properties of the lower Wilcox aquifer of the Mississippi Embayment aquifer system in Missouri and Arkansas, the advection-dispersion equation was solved along a 1-D groundwater flow domain, coupled with a cross-contact aquitard-aquifer diffusive flux. Although the observed signal within the lower Wilcox was not matched, a sensitivity analysis indicated the importance of the isotope composition gradient between the aquifer and aquitard. Furthermore, groundwater velocity was suggested as a controlling influence on aquitard-aquifer exchange that could alter aquifer isotope composition.
36
Thomas, Abraham. "A geographic information system methodology for modelling urban groundwater recharge and pollution." Thesis, University of Birmingham, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248814.
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Hansen, Douglas Dale. "Analytic modeling of leakage in confined aquifer systems /." Diss., ON-CAMPUS Access For University of Minnesota, Twin Cities Click on "Connect to Digital Dissertations", 2002. http://www.lib.umn.edu/articles/proquest.phtml.
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Jiménez, Martínez Joaquin. "Aquifer recharge from intensively irrigated farmland: several approaches." Doctoral thesis, Universitat Politècnica de Catalunya, 2010. http://hdl.handle.net/10803/6267.
Full textAbstract:
En las últimas décadas la literatura se ha centrado en la estimación de la recarga natural y los parámetros que la controlan, incluyendo clima, vegetación, suelo, y topografía. Por el contrario, pocos son los trabajos centrados en la recarga de acuíferos a partir de zonas cultivadas intensamente regadas. Aunque estos han mejorado la compresión sobre el proceso de recarga, todavía resultan incompletos a la hora de estimarla a partir del mencionado uso de suelo. En este contexto, los objetivos de esta tesis son: (i) mejorar la compresión de la recarga a partir de zonas intensamente regadas, y (ii) proporcionar nuevas herramientas para su caracterización. Algunas de las metodologías proporcionadas pueden ser fácilmente reproducidas por profesionales para inferir información cuantitativa. Ensayos en campo, incluyendo diferentes tipos de cultivo y prácticas agrícolas, son llevados a cabo en al área del Campo de Cartagena, sureste de España, una región semi-árida donde la agricultura intensiva es el principal uso de suelo. El desarrollo de metodologías con observaciones en el medio saturado y no saturado, junto con la modelación numérica, fueron usados para mejorar la compresión de los procesos que controlan la recarga a partir de zonas intensamente regadas. Las aproximaciones desarrolladas pueden ser resumidas como sigue:
Ensayo de campo a lo largo de seiscientos días bajo cultivos hortícolas anuales y riego por goteo. La distribución del contenido de agua en la zona de raíces y bajo esta fue simulada considerando un modelo de flujo no saturado. El contenido de agua y la succión fueron medidos a diferentes profundidades y empleados para la calibración y validación del modelo.
Ensayo de trazador (tritio) en campo en una parcela experimental con riego por goteo y cultivos hortícolas anuales durante cuatrocientos treinta días. El movimiento de trazador a lo largo del perfil de suelo fue simulado considerando transporte multifásico. Los perfiles de concentración de trazador, a partir de un espaciado y limitado número de muestras destructivas, fueron usados para calibrar y validar el modelo.
Experimento de larga duración (nueve años hidrológicos) para diferentes tipos de cultivo: cultivos hortícolas anuales, cultivos hortícolas perennes y árboles frutales. La recarga producida por cada tipo de cultivo fue estimada a partir del balance de agua en suelo, zona no saturada y acuífero. Las fluctuaciones del nivel freático registradas a lo largo del mencionado periodo fueron usadas para calibrar y validar el modelo. Esta experiencia permitió evaluar la fiabilidad de las estimaciones de recarga a partir de las otras dos metodologías previas (a corto plazo) para el tipo de cultivo coincidente (cultivos hortícolas anuales).
Para las tres aproximaciones, el cubrimiento de suelo por las plantas y el crecimiento de raíces han sido incluidos en la condición de contorno superior. La evapotranspiración se ha dividido en evaporación y transpiración como una función del índice de área de hoja, y es limitada por el contenido de agua en el suelo. La transpiración a su vez ha sido distribuida a través del perfil de suelo como una función del contenido de agua y profundidad de raíces.
Valores similares de recarga han sido obtenidos a partir de las tres técnicas, aunque el modelo de flujo no saturado la sobreestima ligeramente. La evapotranspiración real fue siempre más baja que la potencial, ya que el contenido de agua en suelo fue insuficiente para mantener la extracción de agua por parte de las raíces, a pesar de la alta frecuencia de riego. Aunque las prácticas agrícolas por parte de los agricultores son las correctas, con una alta eficiencia de riego, se obtuvieron altos valores de recarga. La lluvia es distribuida de manera irregular en unos pocos eventos intensivos, algo por otro lado muy común en regiones semi-áridas, lo que contribuye de manera significativa a la percolación profunda, debido al constante alto contenido de humedad en el suelo.
In the past decades a large body of literature has focused on the assessment of the natural recharge and parameters of control (including climate, vegetation, soils, and topography). On the contrary, only few papers focused on aquifer recharge from intensively irrigated farmland. Although findings have improved the understanding of recharge phenomena, they still fail to characterize many features of aquifer recharge from the mentioned land use. In this context, the aims of this thesis are: (i) to improve the understanding of aquifer recharge from intensively irrigated farmland, and (ii) to provide new tools for its characterization. Also, this thesis provides a framework that can be easily used by practitioners to infer quantitative information.
Field tests, including different crop types and agricultural management, were carried out in the Campo de Cartagena area of southeast Spain, a semi-arid region where intensive irrigated agriculture is prevalent. The development of methodologies, with field observations in both saturated and unsaturated media, along with the application of numerical modelling were used to understand the processes governing the recharge from irrigated farmland. The developed approaches can be summarized as follows:
A field experiment with annual row crops and drip irrigation. Soil moisture dynamics through the root zone and below were simulated from unsaturated flow approach. Soil moisture and pressure head data at different depths were recorded along six hundred days for model calibration and prediction.
A tracer test (tritium) in field along four hundred thirty days. The test was carried out in an experimental plot with drip irrigation and annual row crops. The tracer transport in soil was simulated considering a multiphase approach. Tracer concentration profiles, from a limited and sparse number of destructive samples, were used to calibrate and validate the modelling approach.
A long-term field experiment (based on nine hydrologic years) for different crop types, annual row crops, perennial vegetables and fruit trees. The recharge produced from each crop type was estimated from a water balance approach, including soil, vadose zone and aquifer. Water table fluctuations, recorded along the mentioned period, were used for model calibration and predictions. This long-term approach permits to evaluate recharge estimates reliability of the two previous methodologies (short-term) for the type of crop overlapped (annual row crops).
For the three approaches, ground cover and root depth are assumed as upper boundary conditions. Evapotranspiration is allocated to evaporation and transpiration as a function of leaf-area-index and is limited by soil moisture content; transpiration is distributed through the soil profile as a function of soil moisture and root depth.
Similar recharge values have been obtained from the three techniques, although the unsaturated flow approach slightly overestimates values. Actual evapotranspiration was always lower than potential evapotranspiration, because soil moisture was insufficient to sustain the potential uptake, despite high irrigation frequency. Although the agricultural practices from farmers are sound, high irrigation efficiency, high recharge values are achieved. Rainfall is unevenly distributed into a few intensive events, likewise very common in semi-arid regions, and it meaningfully contributes to deep percolation, due to consistently high soil water content.
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Yagbasan, Ozlem. "Modeling Of Mogan And Eymir Lakes Aquifer System." Phd thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608456/index.pdf.
Full textAbstract:
Mogan and Eymir Lakes, located 20 km south of Ankara, are important
aesthetic, recreational, and ecological resources. DikilitaS and ikizce reservoirs,
constructed on upstream surface waters, are two man-made structures in the basin
encompassing an area of 985 km2. The purpose of this study is (1) to quantify
groundwater components in lakes&rsquobudgets, (2) to assess the potential impacts of upstream reservoirs on lake levels, and (3) to determine effects of potential climatic change on lakes and groundwater levels in the basin. Available data have been used to develop a conceptual model of the system. The three dimensional groundwater model (MODFLOW) has been developed for the system. The model has been calibrated successfully under transient conditions over a period of six years using monthly periods. The results show that groundwater inflows and outflows have the lowest contribution to the overall lakes&rsquo
budget. A sensitivity analysis was conducted to determine the limits within which the regional parameters may vary. Three groundwater management scenarios had been developed. The results show that the upstream reservoirs have a significant effect on lake stages but not on groundwater levels. A trade-off curve between the amount of water released and the average stage in Lake Mogan has been developed. The continuation of the existing average conditions shows that there would be declines in groundwater elevations in areas upstream from Lake Mogan and downstream from Lake Eymir. The results also indicated that very small, but long-term changes to precipitation and temperature have the potential to cause significant declines in groundwater and lake levels.
40
Munn, Nigel Duoglas Kenneth. "Effluent Dispersal to the Chalk Aquifer in Hampshire." Thesis, University of Brighton, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.506513.
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Nicol, Ryan Charles Smith. "Hydrogeology of the Cromwell Terrace Aquifer, Central Otago." Thesis, University of Canterbury. Geological Sciences, 2011. http://hdl.handle.net/10092/6431.
Full textAbstract:
A hydrogeologic model, groundwater chemistry and stable isotopic analysis were used to establish recharge resources and outflows so a water balance could be developed for the Cromwell Terrace Aquifer (CTA) in Central Otago, New Zealand. Increased popularity of the Central Otago region for viticulture, orcharding and tourism, has resulted in an increased demand for water. Groundwater is a viable option to meet this demand for water.
The CTA is a single unconfined aquifer contained within a thin veneer of permeable Quaternary glacial outwash gravels that range in thickness between 10 and 50m. These gravels rest unconformably on less permeable folded Tertiary sediments. The buried surface of the Tertiary sediments is irregular and provides the main hydrogeologic control in the CTA. Buried topographic highs in the Tertiary sediments impede groundwater flow, while the buried paleochannels at the southern end of the Cromwell Flat allow groundwater to flow unrestricted. The saturated thickness of the aquifer varies between 10 and 30 m.
The direction of groundwater flow is in south easterly and south westerly directions toward both Lake Dunstan and the Kawarau Arm respectively. This indicates that recharge is from the Pisa Range. Annual fluctuations in groundwater levels show that there is a seasonal effect on the groundwater table. Annual fluctuations in groundwater level are in the range of 0.4 – 0.5 m, with lowest levels in winter and highest groundwater levels in late summer. The higher groundwater levels in summer correlate with when higher rainfall occurs, but could also be due to artificial recharge from irrigation during summer, and/or seepage from the Ripponvale Irrigation Scheme canals and storage ponds.
Groundwater chemical analysis showed the dominant facies to be calcium bicarbonate waters. The source of the calcium bicarbonate is considered to be calcite in the Otago Schist, with concentrations of calcium bicarbonate being higher closer to the bedrock schist of the Pisa Range. Concentrations decreased toward Lake Dunstan, where calcium bicarbonate concentrations were lowest. The trend of calcium bicarbonate concentrations decreasing toward Lake Dunstan produces a similar pattern to the direction of groundwater flow. This would suggest that calcium bicarbonate concentrations are being diluted by rainwater infiltrating into the aquifer. However stable isotopic analysis showed that lake water infiltrates into the aquifer around the lake margin, and would also dilute calcium bicarbonate concentrations.
Stable isotopic analysis found that groundwater was more depleted in both δ¹⁸O and δ²H than water from Lake Dunstan. The average δ¹⁸O for groundwater was -9.5‰, whereas the average δ¹⁸O for samples from Lake Dunstan was -8.1‰. The average δ¹⁸O value of Pisa Range snow, Pisa Range streams and Cromwell Flat precipitation gave values of -9.2‰ +/- 1.4‰, which is very similar to groundwater. This suggests recharge to the CTA is from a combination of snow melt and surface stream flow from the Pisa Range, and some direct rainfall infiltration on the Cromwell Flat.
A water balance was calculated for the CTA groundwater system using the information from this study, and from a limited Otago Regional Council (O.R.C.) database. The main inputs to the CTA were found to be recharge precipitation and subsurface flows from the Pisa Range. The main outputs were identified as surface evaporation and discharge from the CTA to Lake Dunstan. The water balance showed that the total flow of water through the CTA is 93 Million cubic metres per year (Mm³/yr).
At present the CTA has limited groundwater allocation measures in place. Using the information from the water balance, a volume of groundwater that could be abstracted sustainably was estimated. This volume was estimated using the O.R.C. method of allocating 50% of the mean annual precipitation that recharges the aquifer for groundwater abstraction. The total mean annual precipitation for the Cromwell Flat and Pisa Range is 20 Mm³/yr. Using the 50% of mean annual precipitation method, 10 Mm³/yr can be allocated for groundwater abstraction. The total volume of groundwater currently abstracted is 3 Mm³/yr, leaving 7 Mm³/yr of unallocated groundwater. Due to the small land area, types of land use, low population density of Cromwell Flat and availability of surface water (i.e. Lake Dunstan), it is unlikely that the total volume of 10 Mm³/yr will be fully allocated.
42
Haaken, Klaus [Verfasser]. "Applied hydrogeophysics for managed aquifer recharge / Klaus Haaken." Bonn : Universitäts- und Landesbibliothek Bonn, 2018. http://d-nb.info/1154485927/34.
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Roberts, Shawn Conrad. "Surface/groundwater interactions in the Lincolnshire limestone aquifer." Thesis, University College London (University of London), 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313820.
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Khachikian, Crist Simon. "Sorption of chlorinated solvents in a sandy aquifer." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/40161.
Full textAbstract:
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1996.Includes bibliographical references (leaves 62-67).
by Crist Simon Khachikian.
M.Eng.
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Hoque, M. A. "Models for managing the deep aquifer in Bangladesh." Thesis, University College London (University of London), 2010. http://discovery.ucl.ac.uk/19987/.
Full textAbstract:
In southern Bangladesh excessive levels of As in shallow groundwater have led to deeper groundwater becoming the main alternative source of As-free potable water. Hydrogeological configuration indicates that tube-wells pumping from these depths may be vulnerable to As breakthrough from shallow levels. The thesis explores a range of methods of representing lithological heterogeneity of the Bengal Aquifer System (BAS) in models of groundwater flow and travel time. The aim is to support models of arsenic (As) flux to the deep groundwater flow-system of BAS, and hence to aid assessment of the vulnerability of deep groundwater to invasion by As. The research uses an array of geological information including geophysical logs (n=12), hydrocarbon exploration data (n=11), and drillers' logs (n=589) from a 5000 km2 area to characterise the aquifer heterogeneity as a basis for alternative representations of hydrogeological structure in groundwater flow modelling. Groundwater samples from southern Bangladesh were analysed for 14C in order to determine groundwater age (n=23) and for hydrochemical (n=75) and isotopic (n=50) characterisation. A new hypothesis `SiHA (Silt-clay layers influence Hierarchical groundwater flow systems and Arsenic progression in aquifer)' is presented which integrates sedimentological heterogeneities, groundwater flow, and geochemical processes to explain the distribution and geological evolution of groundwater As in the aquifer. The hypothesis explains the spatio-vertical variability of groundwater As concentration by 'groundwater flow systems and differential flushing' in the aquifer. Groundwater flow models based on eight different yet plausible aquifer representations provide adequate simulations of hydraulic head, but contrasting implications for well catchments and travel times. The better representations are judged by comparing model outcomes of travel time with groundwater age determination using 14C. Comparisons demonstrate the importance of incorporating hydrostratigraphy and spatial heterogeneity in order to optimise model representations, and implications for the security of As-free deep groundwater in the BAS.
46
Zhu, Junfeng, and Tian-Chyi J. Yeh. "Characterization of aquifer heterogeneity using transient hydraulic tomography." Department of Hydrology and Water Resources, University of Arizona (Tucson, AZ), 2004. http://hdl.handle.net/10150/615765.
Full textAbstract:
Hydraulic tomography is a cost -effective technique for characterizing the heterogeneity of hydraulic parameters in the subsurface. During hydraulic tomography surveys, a large number of hydraulic heads (i.e., aquifer responses) are collected from a series of pumping or injection tests in an aquifer. These responses are then used to interpret the spatial distribution of hydraulic parameters of the aquifer using inverse modeling. In this study, we developed an efficient sequential successive linear estimator (SSLE) for interpreting data from transient hydraulic tomography to estimate three-dimensional hydraulic conductivity and specific storage fields of aquifers. We first explored this estimator for transient hydraulic tomography in a hypothetical one-dimensional aquifer. Results show that during a pumping test, transient heads are highly correlated with specific storage at early time but with hydraulic conductivity at late time. Therefore, reliable estimates of both hydraulic conductivity and specific storage must exploit the head data at both early and late times. Our study also shows that the transient heads are highly correlated over time, implying only infrequent head measurements are needed during the estimation. Applying this sampling strategy to a well -posed problem, we show that our SSLE can produce accurate estimates of both hydraulic conductivity and specific storage fields. The benefit of hydraulic tomography for ill -posed problems is then demonstrated. Finally, to affirm the robustness of our SSLE approach, we apply the SSLE approach to transient hydraulic tomography in a hypothetical two- dimensional aquifer with nonstationary hydraulic properties, as well as a hypothetical three-dimensional heterogeneous aquifer.
47
Brown, Steven Robin 1961. "Unconfined aquifer recharge from water table configuration modeling." Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/191899.
Full textAbstract:
The potential of estimating steady recharge to deep unconfined aquifers by comparing observed water levels to the water levels produced by a series of simulated cases was examined. Finite-element simulations were performed on an idealized region to examine the sensitivity of the water table position to anisotropy, recharge, grid density, horizontal layering, and region geometry. The position of the water table was found to be particularly sensitive to region geometry, medium heterogeneity and anisotropy. A graphical method based on comparison of water levels at three observation points to simulated water levels produced a good estimate of dimensionless recharge and the anisotropy ratio. Determination of the absolute value of recharge requires accurate determination of region geometry and hydraulic conductivity so that computer simulations are representative. An analytical solution to the Boussinesq equation was found to give a poor estimate of water table position and hence recharge for this case.
48
Kolesnik, Lindgren Julian. "Aquifer Thermal Energy Storage : Impact on groundwater chemistry." Thesis, KTH, Hållbar utveckling, miljövetenskap och teknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-232110.
Full textAbstract:
Groundwater is potentially a useful source for storing and providing thermal energy to the built environment. In a nordic context, aquifer thermal energy storage, (ATES) has not been subject to a wider extent of research concerning environmental impact. This thesis intends to study the impact on groundwater chemistry from an ATES that has been operational since 2016 and is located in the northern part of Stockholm, on a glaciofluvial deposit called the Stockholm esker. Analysis of groundwater sampling included a period of 9 months prior to ATES operation as well as a 7 month period after operation and sampling was conducted in a group of wells in vicinity of the installation and within the system as ATES operation began. Means of evaluation constituted a statistical approach which included Kruskal-Wallis test by ranks, to compare the ATES wells with the wells in the surroundings and principal component analysis, (PCA), to study the chemical parameters that could be related to ATES. In addition, a geophysical survey comprising 2D-resistivity and induced polarization, (IP) was done to elucidate whether the origin of high salinity could be traced to nearby possible sources. The analysis was based on foremost the cycle of cold energy storage. The results showed large variations in redox potential, particularly at the cold wells which likely was due to the mixing of groundwater considering the different depths of groundwater being abstracted/injected from different redox zones. Arsenic, which has shown to be sensitive to high temperatures in other research showed a decrease in concentration compared to surrounding wells. There were found to be a lower specific conductivity and total hardness at the ATES well compared to their vicinity. That indicates that they are less subject to salinization and that no accumulation has occurred to date. It is evident that the environmental impact from ATES is governed by the pre-conditions in soil- and groundwater.
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Seaton, William. "Aquifer Characterization in the Blue Ridge Physiographic Province." Diss., Virginia Tech, 2002. http://hdl.handle.net/10919/26205.
Full textAbstract:
Existing models of the hydrogeology in the Blue Ridge Province in the eastern United States generally assume a simplified two-layered system consisting of shallow unconsolidated and relatively homogeneous and porous regolith with a water-table aquifer that slowly supplies water downward to the underlying variably fractured crystalline bedrock. In these models, interconnected fractures in the crystalline bedrock act as conduits for predominantly downward vertical and limited horizontal flow. Fracture density is depthà limited and correlated with proximity to topographic lineaments. Current models consider the porous regolith as the primary water storage reservoir for the entire aquifer system.
In this research, detailed hydrogeologic studies in the Blue Ridge Province in Floyd County, Virginia reveal a substantially different framework for groundwater flow. Recent acquisition of two-dimensional surface resistivity profiles collected using a variety of array techniques combined with borehole geophysical logs revealed new insights into this geologically complex province. Dipole-dipole arrays were particularly important in gathering high resolution resistivity profiles that document horizontal and vertical resistivity variation reflecting changes in subsurface geology and anomalous low resistivity areas in crystalline bedrock associated with fault zones.
The shallow regolith contains unsaturated areas and also localized sand and clay prone facies with water table and confined aquifer conditions residing locally. Hydraulic heads between the shallow aquifer and the deeper fractured bedrock aquifer can vary by 20 m vertically. Within the crystalline bedrock are anomalous lower resistivity intervals associated with ancient fault shear zones. Brecciated rock adjacent to the shear zones, and the shear zones themselves, can be hydraulically conductive and serve as pathways for groundwater movement. Aquifer testing of the regolith-bedrock fracture system occurred over a 6-day period and produced rapid and relatively uniform drawdowns in surrounding wells completed in the fractured bedrock aquifers. The shallow aquifers experienced minimal drawdowns from the aquifer test indicating low vertical hydraulic conductivity and limited communication between the shallow and deeper bedrock aquifers. Water chemistry and chlorofluorocarbon (CFC) age dating analyses indicated significant differences between water samples from the shallow and deep aquifers. A new conceptual model for Blue Ridge aquifers is proposed based on these research findings.Ph. D.
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Jeng, D. Isaac. "A Three-dimensional Model of Poroviscous Aquifer Deformation." Diss., Virginia Tech, 2005. http://hdl.handle.net/10919/29977.
Full textAbstract:
A mathematical model is developed for quantification of aquifer deformation due to ground-water withdrawal and, with some modifications, is potentially applicable to petroleum reservoirs. A porous medium saturated with water is conceptually treated in the model as a nonlinearly viscous fluid continuum. The model employs a new three-dimensional extension, made in this thesis, of Helm's poroviscosity as a constitutive law governing the stress-strain relation of material deformation and Gersevanov's generalization of Darcy's law for fluid flow in porous media. Relative to the classical linear poroelasticity, the proposed model provides a more realistic tool, yet with greater simplicity, in modeling and prediction of aquifer movement.
Based on laboratory consolidation tests conducted on clastic sedimentary materials, three phases of skeletal compaction are recognized. They are referred to as "instantaneous compression", "primary consolidation" and "secondary compression" according to Terzaghi and Biot's theory of poroelasticity. Among the three modes of consolidation, material behavior during the secondary compression phase has a nonlinear stress-strain relationship and is strongly time-dependent, exhibiting a phenomenon often known as "creep". In poroelasticity, the primary and secondary compressions have been conceptually considered as two separate physical processes that require two sets of material parameters to be evaluated. In contrast, the proposed poroviscosity model is a unified theory of time-dependent skeletal compression that realistically describes the physical phenomena of sediment compression as one single transient process.
As a general model, two sets of governing equations are formulated for Cartesian and cylindrical coordinates, respectively, and allow for mechanical anisotropy and the assumption of principal hydraulic directions. Further simplifications of the governing equations are formulated by assuming mechanical isotropy, irrotational deformation and mechanical axisymmetry, which are more suitable for field applications. Incremental forms of the governing equations are also provided.Ph. D.