WorldWideScience

Sample records for groundwater flow radionuclide

  1. Radionuclides in groundwater flow system understanding

    Science.gov (United States)

    Erőss, Anita; Csondor, Katalin; Horváth, Ákos; Mádl-Szőnyi, Judit; Surbeck, Heinz

    2017-04-01

    Using radionuclides is a novel approach to characterize fluids of groundwater flow systems and understand their mixing. Particularly, in regional discharge areas, where different order flow systems convey waters with different temperature, composition and redox-state to the discharge zone. Radium and uranium are redox-sensitive parameters, which causes fractionation along groundwater flow paths. Discharging waters of regional flow systems are characterized by elevated total dissolved solid content (TDS), temperature and by reducing conditions, and therefore with negligible uranium content, whereas local flow systems have lower TDS and temperature and represent oxidizing environments, and therefore their radium content is low. Due to the short transit time, radon may appear in local systems' discharge, where its source is the soil zone. However, our studies revealed the importance of FeOOH precipitates as local radon sources throughout the adsorption of radium transported by the thermal waters of regional flow systems. These precipitates can form either by direct oxidizing of thermal waters at discharge, or by mixing of waters with different redox state. Therefore elevated radon content often occurs in regional discharge areas as well. This study compares the results of geochemical studies in three thermal karst areas in Hungary, focusing on radionuclides as natural tracers. In the Buda Thermal Karst, the waters of the distinct discharge areas are characterized by different temperature and chemical composition. In the central discharge area both lukewarm (20-35°C, 770-980 mg/l TDS) and thermal waters (40-65°C, 800-1350 mg/l TDS), in the South only thermal water discharge (33-43°C, 1450-1700 mg/l TDS) occur. Radionuclides helped to identify mixing of fluids and to infer the temperature and chemical composition of the end members for the central discharge area. For the southern discharge zone mixing components could not be identified, which suggests different cave

  2. FTRANS, Radionuclide Flow in Groundwater and Fractured Rock

    International Nuclear Information System (INIS)

    Huyakorn, P.; Golis, M.J.

    1987-01-01

    1 - Description of program or function: FTRANS (Fractured flow and Transport of Radionuclides) is a two-dimensional finite-element code designed to simulate ground-water flow and transport of radioactive nuclides in a fractured porous return medium. FTRANS takes into account fluid interactions between the fractures and porous matrix blocks, advective-dispersive transport in the fractures and diffusion in the porous matrix blocks, and chain reactions of radionuclide components. It has the capability to model the fractured system using either the dual-porosity or the discrete- fracture modeling approach or a combination of both. FTRANS can be used to perform two-dimensional near-field or far-field predictive analyses of ground-water flow and to perform risk assessments of radionuclide transport from nuclear waste repository subsystems to the biosphere. 2 - Restrictions on the complexity of the problem: Although FTRANS does cannot account for deformation processes which can affect the flow capacity and velocity field

  3. Simple evaluation of groundwater flow and radionuclide transport at Aespoe

    International Nuclear Information System (INIS)

    Dverstorp, B.; Geier, J.; Voss, C.

    1996-12-01

    A simple evaluation of groundwater flux and potential for radionuclide transport at the Aespoe site, from fundamental hydrologic principles, indicates that, based upon data that are available from surface-based investigations, it is not possible to confirm that the bedrock has a high capacity to retard radionuclide release to the surface environment. This result is primarily due to the high spatial variability of hydraulic conductivity, and high uncertainty regarding the relationship among hydrologic and transport parameters within conductive elements of the bedrock. A comparison between Aespoe and seven other study sites in Sweden indicates that it is difficult or impossible to discriminate among these sites in terms of the geologic barrier function, based upon the types of data that are available from present-day methods of site characterization. Groundwater flux is evaluated by a one-dimensional application of Darcy's law to a set of simple, potential pathways for groundwater flow from the repository, which are chosen to yield an appraisal of the wide bounds of possible system behaviour. The configurations of the pathways are specified based on simple assumptions of flow-field structure, and hydraulic driving forces are specified from consideration of regional and local topographic differences. Results are expressed in terms of a parameter group that has been shown to control the barrier function. Comparisons with more detailed hydrological modelling of Aespoe show that, although a reduction in uncertainty is achieved, this reduction is not sufficient to distinguish between good and poor performance of the geologic barrier at the site. 38 refs

  4. Effects of macropores on groundwater flow and transport of radionuclides

    International Nuclear Information System (INIS)

    Huff, D.D.; DeAngelis, D.L.; Yeh, G.T.

    1983-01-01

    In humid environments, recent findings have shown that an important component of runoff and associated solute moves rapidly through large continuous voids. Thus, consideration of radionuclide transport in subsurface flow is incomplete without explicit treatment of continuous macropores and interaction between macropore flow and the soil matrix. A computer model, FRACPORT, that simulates the transport of a solute through a fractured porous matrix has been developed. The model employs the Integrated Compartment Method and uses the approach of dividing the porous media into compartments comprising fractures or porous material. The fracture region and a small portion of the porous matrix are simulated using a shorter time step than for the remaining porous matrix. This allows substantial savings in computational time. The model should be useful for analyses of generic problems associated with water and radionuclide transport in macropore systems at shallow-land disposal sites in humid environments. 14 references, 6 figures, 1 table

  5. Transient simulation and sensitivity analysis for transport of radionuclides in a saturated-unsaturated groundwater flow system

    International Nuclear Information System (INIS)

    Chen, H.H.

    1980-01-01

    Radionuclide transport by groundwater flow is an important pathway in the assessment of the environmental impact of radioactive waste disposal to the biosphere. A numerical model was developed to simulate radionuclide transport by groundwater flow and predict the radionuclide discharge rate to the biosphere. A sensitivity analysis methodology was developed to address the sensitivity of the input parameters of the radionuclide transport equation to the specified response of interest

  6. Theoretical background and user's manual for the computer code on groundwater flow and radionuclide transport calculation in porous rock

    International Nuclear Information System (INIS)

    Shirakawa, Toshihiko; Hatanaka, Koichiro

    2001-11-01

    In order to document a basic manual about input data, output data, execution of computer code on groundwater flow and radionuclide transport calculation in heterogeneous porous rock, we investigated the theoretical background about geostatistical computer codes and the user's manual for the computer code on groundwater flow and radionuclide transport which calculates water flow in three dimension, the path of moving radionuclide, and one dimensional radionuclide migration. In this report, based on above investigation we describe the geostatistical background about simulating heterogeneous permeability field. And we describe construction of files, input and output data, a example of calculating of the programs which simulates heterogeneous permeability field, and calculates groundwater flow and radionuclide transport. Therefore, we can document a manual by investigating the theoretical background about geostatistical computer codes and the user's manual for the computer code on groundwater flow and radionuclide transport calculation. And we can model heterogeneous porous rock and analyze groundwater flow and radionuclide transport by utilizing the information from this report. (author)

  7. Studies on groundwater flow and radionuclide migration at underground environments. Final report of collaboration research between JAERI and AECL

    International Nuclear Information System (INIS)

    Ogawa, Hiromichi; Nagao, Seiya; Yamaguchi, Tetsuji

    2001-01-01

    The Japan Atomic Energy Research Institute (JAERI) conducted a collaboration program Phase II with the Atomic Energy of Canada Limited (AECL) from 1994 to 1998. The program was started to contribute the establishment of safety assessment methodology for the geological disposal of high-level radioactive wastes on the basis of the results from the Phase I program (1987-1993). The Phase II program consisted of following experimental items: (1) radionuclide migration experiments for quarried blocks (1m x 1m x 1m) of granite with natural fracture under in-situ geochemical conditions at 240 m level of Underground Research Laboratory of AECL; (2) study on the effects of dissolved organic materials extracted from natural groundwaters on radionuclide migration; (3) study on groundwater flow using environmental isotopes at two different geologic environments; (4) development of groundwater flow and radionuclide transport model for heterogeneous geological media. The mobility of radionuclides was retarded in the fracture by the deep geological conditions and the fracture paths. The groundwater humic substances with high molecular size were enhanced for the mobility of radionuclides in the sand and granitic media due to the complexation. The application of 36 Cl and 129 I for the analysis on the long-term groundwater flow can be validated on the basis of investigation at the URL site. Moreover, the geostatistical model for the analysis on groundwater flow and radionuclide migration was developed, and was able to describe the groundwater flow and the migration of environmental tracers at AECL sites. This report summaries the results of the Phase II program between JAERI and AECL. (author)

  8. Studies on groundwater flow and radionuclide migration at underground environments. Final report of collaboration research between JAERI and AECL

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, Hiromichi; Nagao, Seiya; Yamaguchi, Tetsuji [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment] [and others

    2001-01-01

    The Japan Atomic Energy Research Institute (JAERI) conducted a collaboration program Phase II with the Atomic Energy of Canada Limited (AECL) from 1994 to 1998. The program was started to contribute the establishment of safety assessment methodology for the geological disposal of high-level radioactive wastes on the basis of the results from the Phase I program (1987-1993). The Phase II program consisted of following experimental items: (1) radionuclide migration experiments for quarried blocks (1m x 1m x 1m) of granite with natural fracture under in-situ geochemical conditions at 240 m level of Underground Research Laboratory of AECL; (2) study on the effects of dissolved organic materials extracted from natural groundwaters on radionuclide migration; (3) study on groundwater flow using environmental isotopes at two different geologic environments; (4) development of groundwater flow and radionuclide transport model for heterogeneous geological media. The mobility of radionuclides was retarded in the fracture by the deep geological conditions and the fracture paths. The groundwater humic substances with high molecular size were enhanced for the mobility of radionuclides in the sand and granitic media due to the complexation. The application of {sup 36}Cl and {sup 129}I for the analysis on the long-term groundwater flow can be validated on the basis of investigation at the URL site. Moreover, the geostatistical model for the analysis on groundwater flow and radionuclide migration was developed, and was able to describe the groundwater flow and the migration of environmental tracers at AECL sites. This report summaries the results of the Phase II program between JAERI and AECL. (author)

  9. Groundwater flow and radionuclide transport modelling using CONNECTFLOW in support of the SR Can assessment

    International Nuclear Information System (INIS)

    Hartley, Lee; Cox, Ian; Holton, David; Hunter, Fiona; Joyce, Steve; Gylling, Bjoern; Lindgren, Maria

    2004-09-01

    SKB is currently pursuing site investigations for a deep repository in the municipalities of Oesthammar and Oskarshamn. The investigations are conducted in two stages; an initial phase followed by a complete site investigation phase. The favoured alternative for the location of the encapsulation plant is at Oskarshamn, where it would operate in conjunction with the existing interim storage facility. These two planning applications will each require a report on the long-term safety of the deep repository. In the case of the encapsulation plant, such a report will demonstrate that a repository for the sealed canisters will meet the requirements on long-term safety set up by the Swedish authorities. The two safety reports will be referred to as SR-Can and SR-Site, for the encapsulation plant and repository, respectively. SR-Can will be based on site data from the initial site investigation phase and SR-Site on data from the complete site investigation. The preliminary safety evaluations for each site will be carried out as sub-tasks within the SR-Can project. The main purposes of those evaluations are to: Determine whether earlier judgements of the suitability of the candidate area for a deep repository with respect to long-term safety holds up in the light of borehole data; Provide feed-back to continued site investigations and site-specific repository design. A proposed methodology for the SR-Can assessment has been published in SKB TR-03-08. The methodology envisaged the use of both continuum porous medium (CPM) and discrete fracture network (DFN) models on a range of scales to investigate the groundwater flow and radionuclide transport from a deep disposal facility to the biosphere. The modelling must address the effects of variable groundwater density and transients. Transients occur naturally as a consequence of changes in climate states (temperate, periglacial and glacial) and during the operational and immediate post-closure phases of the repository. Key

  10. Natural radionuclides in groundwaters

    International Nuclear Information System (INIS)

    Laul, J.C.

    1990-01-01

    The U-234 and Th-230 radionuclides are highly retarded by factors of 10 4 to 10 5 in basalt groundwater (Hanford) and briny groundwaters from Texas and geothermal brine from the Salton Sea Geothermal Field (SSGF). In basalt groundwaters (low ionic strength), Ra is highly sorbed, while in brines (high ionic strength), Ra is soluble. This is probably because the sorption sites are saturated with Na + and Cl - ions and RaCl 2 is soluble in brines. Pb-210 is soluble in SSGF brine, probably as a chloride complex. The U-234/Th-230 ratios in basalt groundwaters and brines from Texas and SSGF are nearly unity, indicating that U is in the +4 state, suggesting a reducing environment for these aquifers. 19 refs., 3 figs

  11. Natural radionuclides in groundwaters

    International Nuclear Information System (INIS)

    Laul, J.C.

    1992-01-01

    The 234 U and 230 Th radionuclides are highly retarded by factors of 10 4 to 10 5 in basalt groundwater (Hanford) and briny groundwaters from Texas, and geothermal brine form the Salton Sea Geothermal Field (SSGF). In basalt groundwaters (low ionic strength), Ra is highly sorbed, while in brines (high ionic strength), Ra is soluble. This is probably because the sorption sites are saturated with Na + and Cl - ions, and RaCl 2 is soluble in brines. 210 Pb is soluble in SSGF brine, probably as a chloride complex. The 234 U/ 230 Th ratios in basalt groundwaters and brines from Texas and SSGF are nearly unity, indicating that U is in the +4 state, suggesting a reducing environment for these aquifers. (author) 19 refs.; 3 figs

  12. URANIUM-SERIES CONSTRAINTS ON RADIONUCLIDE TRANSPORT AND GROUNDWATER FLOW AT NOPAL I URANIUM DEPOSIT, SIERRA PENA BLANCA, MEXICO

    Energy Technology Data Exchange (ETDEWEB)

    S. J. Goldstein, S. Luo, T. L. Ku, and M. T. Murrell

    2006-04-01

    Uranium-series data for groundwater samples from the vicinity of the Nopal I uranium ore deposit are used to place constraints on radionuclide transport and hydrologic processes at this site, and also, by analogy, at Yucca Mountain. Decreasing uranium concentrations for wells drilled in 2003 suggest that groundwater flow rates are low (< 10 m/yr). Field tests, well productivity, and uranium isotopic constraints also suggest that groundwater flow and mixing is limited at this site. The uranium isotopic systematics for water collected in the mine adit are consistent with longer rock-water interaction times and higher uranium dissolution rates at the front of the adit where the deposit is located. Short-lived nuclide data for groundwater wells are used to calculate retardation factors that are on the order of 1,000 for radium and 10,000 to 10,000,000 for lead and polonium. Radium has enhanced mobility in adit water and fractures near the deposit.

  13. URANIUM-SERIES CONSTRAINTS ON RADIONUCLIDE TRANSPORT AND GROUNDWATER FLOW AT NOPAL I URANIUM DEPOSIT, SIERRA PENA BLANCA, MEXICO

    International Nuclear Information System (INIS)

    S. J. Goldstein, S. Luo, T. L. Ku, and M. T. Murrell

    2006-01-01

    Uranium-series data for groundwater samples from the vicinity of the Nopal I uranium ore deposit are used to place constraints on radionuclide transport and hydrologic processes at this site, and also, by analogy, at Yucca Mountain. Decreasing uranium concentrations for wells drilled in 2003 suggest that groundwater flow rates are low (< 10 m/yr). Field tests, well productivity, and uranium isotopic constraints also suggest that groundwater flow and mixing is limited at this site. The uranium isotopic systematics for water collected in the mine adit are consistent with longer rock-water interaction times and higher uranium dissolution rates at the front of the adit where the deposit is located. Short-lived nuclide data for groundwater wells are used to calculate retardation factors that are on the order of 1,000 for radium and 10,000 to 10,000,000 for lead and polonium. Radium has enhanced mobility in adit water and fractures near the deposit

  14. TYBO/BENHAM: Model Analysis of Groundwater Flow and Radionuclide Migration from Underground Nuclear Tests in Southwestern Pahute Mesa, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Andrew Wolfsberg; Lee Glascoe; Guoping Lu; Alyssa Olson; Peter Lichtner; Maureen McGraw; Terry Cherry; Guy Roemer

    2002-09-01

    Recent field studies have led to the discovery of trace quantities of plutonium originating from the BENHAM underground nuclear test in two groundwater observation wells on Pahute Mesa at the Nevada Test Site. These observation wells are located 1.3 km from the BENHAM underground nuclear test and approximately 300 m from the TYBO underground nuclear test. In addition to plutonium, several other conservative (e.g. tritium) and reactive (e.g. cesium) radionuclides were found in both observation wells. The highest radionuclide concentrations were found in a well sampling a welded tuff aquifer more than 500m above the BENHAM emplacement depth. These measurements have prompted additional investigations to ascertain the mechanisms, processes, and conditions affecting subsurface radionuclide transport in Pahute Mesa groundwater. This report describes an integrated modeling approach used to simulate groundwater flow, radionuclide source release, and radionuclide transport near the BENHAM and TYBO underground nuclear tests on Pahute Mesa. The components of the model include a flow model at a scale large enough to encompass many wells for calibration, a source-term model capable of predicting radionuclide releases to aquifers following complex processes associated with nonisothermal flow and glass dissolution, and site-scale transport models that consider migration of solutes and colloids in fractured volcanic rock. Although multiple modeling components contribute to the methodology presented in this report, they are coupled and yield results consistent with laboratory and field observations. Additionally, sensitivity analyses are conducted to provide insight into the relative importance of uncertainty ranges in the transport parameters.

  15. The far field migration of radionuclides in two dimensional groundwater flows though geologic media

    International Nuclear Information System (INIS)

    Ting, D.K.S.; Chambre, P.

    1985-01-01

    An analytical method to model the radionuclides migration in a two dimensional groundwater flor through geologic media has been developed and implemented into the computer code UCBNE21. Using this method, the potential hazard to the biosphere posed by the accidental release of radionuclides from a candidate repository site (WIPP) is determined. I-129 and Ra-226 are potentially the most hazardous nuclides in these sites but their discharge into the biosphere will not result in concentrations larger than their maximum permissible concentrations. (Author) [pt

  16. In-situ radionuclide transport and preferential groundwater flows at INEEL (Idaho): Decay-series disequilibrium studies

    International Nuclear Information System (INIS)

    Luo, S.; Ku, T.L.; Roback, R.; Murrell, M.; McLing, T.L.

    2000-01-01

    Uranium and thorium-decay series disequilibria in groundwater occur as a result of water-rock interactions, and they provide site-specific, natural analog information for assessment of in-situ, long-term migration of radionuclides in the far field of a nuclear waste disposal site. In this study, a mass balance model was used to relate the decay-series radionuclide distributions among solution, sorbed and solid phases in an aquifer system to processes of water transport, sorption-desorption, dissolution-precipitation, radioactive ingrowth-decay, and α recoil. Isotopes of U and Rn were measured in 23 groundwater samples collected from a basaltic aquifer at the Idaho National Engineering and Environmental Laboratory (INEEL), Idaho. The results show that groundwater activities of Th and Ra isotopes are 2--4 orders lower than those of their U progenitors. Modeling of the observed disequilibria places the following constraints on the time scale of radionuclide migration and water-rock interaction at INEEL: (1) Time for sorption is minutes for Ra and Th; time for desorption is days for Ra and years for Th; and time for precipitation is days for Th, years for Ra, and centuries for U. (2) Retardation factors due to sorption average > 10 6 for 232 Th, approximately10 4 for 226 Ra, and approximately10 3 for 238 U. (3) Dissolution rates of rocks are approximately70 to 800 mg/L/y. (4) Ages of groundwater range from 222 Rn occur near the groundwater recharging sites as well as in the major flow pathways. Decay of the sorbed parent radionuclides (e.g., 226 Ra and 228 Ra) on micro-fracture surfaces constitutes an important source of their daughter ( 222 Rn and 228 Th) activities in groundwater

  17. Benchmark studies of computer prediction techniques for equilibrium chemistry and radionuclide transport in groundwater flow

    International Nuclear Information System (INIS)

    Broyd, T.W.

    1988-01-01

    A brief review of two recent benchmark exercises is presented. These were separately concerned with the equilibrium chemistry of groundwater and the geosphere migration of radionuclides, and involved the use of a total of 19 computer codes by 11 organisations in Europe and Canada. A similar methodology was followed for each exercise, in that series of hypothetical test cases were used to explore the limits of each code's application, and so provide an overview of current modelling potential. Aspects of the user-friendliness of individual codes were also considered. The benchmark studies have benefited participating organisations by providing a means of verifying current codes, and have provided problem data sets by which future models may be compared. (author)

  18. Modeling of Groundwater Flow and Radionuclide Transport at the Climax Mine sub-CAU, Nevada Test Site

    International Nuclear Information System (INIS)

    K. Pohlmann; M. Ye; D. Reeves; M. Zavarin; D. Decker; J. Chapman

    2007-01-01

    The Yucca Flat-Climax Mine Corrective Action Unit (CAU) on the Nevada Test Site comprises 747 underground nuclear detonations, all but three of which were conducted in alluvial, volcanic, and carbonate rocks in Yucca Flat. The remaining three tests were conducted in the very different hydrogeologic setting of the Climax Mine granite stock located in Area 15 at the northern end of Yucca Flat. As part of the Corrective Action Investigation (CAI) for the Yucca Flat-Climax Mine CAU, models of groundwater flow and radionuclide transport will be developed for Yucca Flat. However, two aspects of these CAU-scale models require focused modeling at the northern end of Yucca Flat beyond the capability of these large models. First, boundary conditions and boundary flows along the northern reaches of the Yucca Flat-Climax Mine CAU require evaluation to a higher level of detail than the CAU-scale Yucca Flat model can efficiently provide. Second, radionuclide fluxes from the Climax tests require analysis of flow and transport in fractured granite, a unique hydrologic environment as compared to Yucca Flat proper. This report describes the Climax Mine sub-CAU modeling studies conducted to address these issues, with the results providing a direct feed into the CAI for the Yucca Flat-Climax Mine CAU. Three underground nuclear detonations were conducted for weapons effects testing in the Climax stock between 1962 and 1966: Hard Hat, Pile Driver, and Tiny Tot. Though there is uncertainty regarding the position of the water table in the stock, it is likely that all three tests were conducted in the unsaturated zone. In the early 1980s, the Spent Fuel Test-Climax (SFT-C) was constructed to evaluate the feasibility of retrievable, deep geologic storage of commercial nuclear reactor wastes. Detailed mapping of fractures and faults carried out for the SFT-C studies greatly expanded earlier data sets collected in association with the nuclear tests and provided invaluable information for

  19. Modeling of Groundwater Flow and Radionuclide Transport at the Climax Mine sub-CAU, Nevada Test Site

    Energy Technology Data Exchange (ETDEWEB)

    K. Pohlmann; M. Ye; D. Reeves; M. Zavarin; D. Decker; J. Chapman

    2007-09-28

    The Yucca Flat-Climax Mine Corrective Action Unit (CAU) on the Nevada Test Site comprises 747 underground nuclear detonations, all but three of which were conducted in alluvial, volcanic, and carbonate rocks in Yucca Flat. The remaining three tests were conducted in the very different hydrogeologic setting of the Climax Mine granite stock located in Area 15 at the northern end of Yucca Flat. As part of the Corrective Action Investigation (CAI) for the Yucca Flat-Climax Mine CAU, models of groundwater flow and radionuclide transport will be developed for Yucca Flat. However, two aspects of these CAU-scale models require focused modeling at the northern end of Yucca Flat beyond the capability of these large models. First, boundary conditions and boundary flows along the northern reaches of the Yucca Flat-Climax Mine CAU require evaluation to a higher level of detail than the CAU-scale Yucca Flat model can efficiently provide. Second, radionuclide fluxes from the Climax tests require analysis of flow and transport in fractured granite, a unique hydrologic environment as compared to Yucca Flat proper. This report describes the Climax Mine sub-CAU modeling studies conducted to address these issues, with the results providing a direct feed into the CAI for the Yucca Flat-Climax Mine CAU. Three underground nuclear detonations were conducted for weapons effects testing in the Climax stock between 1962 and 1966: Hard Hat, Pile Driver, and Tiny Tot. Though there is uncertainty regarding the position of the water table in the stock, it is likely that all three tests were conducted in the unsaturated zone. In the early 1980s, the Spent Fuel Test-Climax (SFT-C) was constructed to evaluate the feasibility of retrievable, deep geologic storage of commercial nuclear reactor wastes. Detailed mapping of fractures and faults carried out for the SFT-C studies greatly expanded earlier data sets collected in association with the nuclear tests and provided invaluable information for

  20. Uranium-series constraints on radionuclide transport and groundwater flow at the Nopal I uranium deposit, Sierra Pena Blanca, Mexico.

    Science.gov (United States)

    Goldstein, Steven J; Abdel-Fattah, Amr I; Murrell, Michael T; Dobson, Patrick F; Norman, Deborah E; Amato, Ronald S; Nunn, Andrew J

    2010-03-01

    Uranium-series data for groundwater samples from the Nopal I uranium ore deposit were obtained to place constraints on radionuclide transport and hydrologic processes for a nuclear waste repository located in fractured, unsaturated volcanic tuff. Decreasing uranium concentrations for wells drilled in 2003 are consistent with a simple physical mixing model that indicates that groundwater velocities are low ( approximately 10 m/y). Uranium isotopic constraints, well productivities, and radon systematics also suggest limited groundwater mixing and slow flow in the saturated zone. Uranium isotopic systematics for seepage water collected in the mine adit show a spatial dependence which is consistent with longer water-rock interaction times and higher uranium dissolution inputs at the front adit where the deposit is located. Uranium-series disequilibria measurements for mostly unsaturated zone samples indicate that (230)Th/(238)U activity ratios range from 0.005 to 0.48 and (226)Ra/(238)U activity ratios range from 0.006 to 113. (239)Pu/(238)U mass ratios for the saturated zone are 1000 times lower than the U mobility. Saturated zone mobility decreases in the order (238)U approximately (226)Ra > (230)Th approximately (239)Pu. Radium and thorium appear to have higher mobility in the unsaturated zone based on U-series data from fractures and seepage water near the deposit.

  1. Uranium-series constraints on radionuclide transport and groundwater flow at the Nopal I uranium deposit, Sierra Pena Blanca, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Goldstein, S.J.; Abdel-Fattah, A.I.; Murrell, M.T.; Dobson, P.F.; Norman, D.E.; Amato, R.S.; Nunn, A. J.

    2009-10-01

    Uranium-series data for groundwater samples from the Nopal I uranium ore deposit were obtained to place constraints on radionuclide transport and hydrologic processes for a nuclear waste repository located in fractured, unsaturated volcanic tuff. Decreasing uranium concentrations for wells drilled in 2003 are consistent with a simple physical mixing model that indicates that groundwater velocities are low ({approx}10 m/y). Uranium isotopic constraints, well productivities, and radon systematics also suggest limited groundwater mixing and slow flow in the saturated zone. Uranium isotopic systematics for seepage water collected in the mine adit show a spatial dependence which is consistent with longer water-rock interaction times and higher uranium dissolution inputs at the front adit where the deposit is located. Uranium-series disequilibria measurements for mostly unsaturated zone samples indicate that {sup 230}Th/{sup 238}U activity ratios range from 0.005-0.48 and {sup 226}Ra/{sup 238}U activity ratios range from 0.006-113. {sup 239}Pu/{sup 238}U mass ratios for the saturated zone are <2 x 10{sup -14}, and Pu mobility in the saturated zone is >1000 times lower than the U mobility. Saturated zone mobility decreases in the order {sup 238}U{approx}{sup 226}Ra > {sup 230}Th{approx}{sup 239}Pu. Radium and thorium appear to have higher mobility in the unsaturated zone based on U-series data from fractures and seepage water near the deposit.

  2. Uranium-series constraints on radionuclide transport and groundwater flow at the Nopal I uranium deposit, Sierra Pena Blanca, Mexico

    International Nuclear Information System (INIS)

    Goldstein, S.J.; Abdel-Fattah, A.I.; Murrell, M.T.; Dobson, P.F.; Norman, D.E.; Amato, R.S.; Nunn, A.J.

    2009-01-01

    Uranium-series data for groundwater samples from the Nopal I uranium ore deposit were obtained to place constraints on radionuclide transport and hydrologic processes for a nuclear waste repository located in fractured, unsaturated volcanic tuff. Decreasing uranium concentrations for wells drilled in 2003 are consistent with a simple physical mixing model that indicates that groundwater velocities are low (∼10 m/y). Uranium isotopic constraints, well productivities, and radon systematics also suggest limited groundwater mixing and slow flow in the saturated zone. Uranium isotopic systematics for seepage water collected in the mine adit show a spatial dependence which is consistent with longer water-rock interaction times and higher uranium dissolution inputs at the front adit where the deposit is located. Uranium-series disequilibria measurements for mostly unsaturated zone samples indicate that 230 Th/ 238 U activity ratios range from 0.005-0.48 and 226 Ra/ 238 U activity ratios range from 0.006-113. 239 Pu/ 238 U mass ratios for the saturated zone are -14 , and Pu mobility in the saturated zone is >1000 times lower than the U mobility. Saturated zone mobility decreases in the order 238 U∼ 226 Ra > 230 Th∼ 239 Pu. Radium and thorium appear to have higher mobility in the unsaturated zone based on U-series data from fractures and seepage water near the deposit.

  3. Study of the influence of hydrogeological conditions in the upper aquifer on radionuclide migration from a geological repository using a 2D groundwater flow model

    Energy Technology Data Exchange (ETDEWEB)

    Shestopalov, Vyacheslav; Bohuslavskyy, Alexander; Shybetskyi, Iurii [National Academy of Science of Ukaraine, Kyiv (Ukraine). Radioenvironmental Centre

    2015-07-01

    Results are presented of a case groundwater flow-transport modeling to predict the radionuclide migration from a deep geological repository (DGR) of radioactive waste. The influence of hydrogeological conditions in the upper aquifers of a storey water exchange system on the rate of contaminant migration from the DGR to its natural far-field groundwater discharges (a shallow well and a river) as a general DGR safety condition is considered.

  4. Groundwater Flow and Radionuclide Transport in Fault Zones in Granitic Rock

    International Nuclear Information System (INIS)

    Geier, Joel Edward

    2004-12-01

    Fault zones are potential paths for release of radioactive nuclides from radioactive-waste repositories in granitic rock. This research considers detailed maps of en echelon fault zones at two sites in southern Sweden, as a basis for analyses of how their internal geometry can influence groundwater flow and transport of radioactive nuclides. Fracture intensity within these zones is anisotropic and correlated over scales of several meters along strike, corresponding to the length and spacing of the en echelon steps. Flow modeling indicates these properties lead to correlation of zone transmissivity over similar scales. Intensity of fractures in the damage zone adjoining en echelon segments decreases exponentially with distance. These fractures are linked to en echelon segments as a hierarchical pattern of branches. Echelon steps also show a hierarchical internal structure. These traits suggest a fractal increase in the amount of pore volume that solute can access by diffusive mass transfer, with increasing distance from en echelon segments. Consequences may include tailing of solute breakthrough curves, similar to that observed in underground tracer experiments at one of the mapping sites. The implications of echelon-zone architecture are evaluated by numerical simulation of flow and solute transport in 2-D network models, including deterministic models based directly on mapping data, and a statistical model. The simulations account for advection, diffusion-controlled mixing across streamlines within fractures and at intersections, and diffusion into both stagnant branch fractures and macroscopically unfractured matrix. The simulations show that secondary fractures contribute to retardation of solute, although their net effect is sensitive to assumptions regarding heterogeneity of transmissivity and transport aperture. Detailed results provide insight into the function of secondary fractures as an immobile domain affecting mass transfer on time scales relevant to

  5. Chemical speciation of radionuclides migrating in groundwaters

    International Nuclear Information System (INIS)

    Robertson, D.; Schilk, A.; Abel, K.; Lepel, E.; Thomas, C.; Pratt, S.; Cooper, E.; Hartwig, P.; Killey, R.

    1994-04-01

    In order to more accurately predict the rates and mechanisms of radionuclide migration from low-level waste disposal facilities via groundwater transport, ongoing studies are being conducted at field sites at Chalk River Laboratories to identify and characterize the chemical speciation of mobile, long-lived radionuclides migrating in groundwaters. Large-volume water sampling techniques are being utilized to separate and concentrate radionuclides into particular, cationic, anionic, and nonionic chemical forms. Most radionuclides are migrating as soluble, anionic species that appear to be predominantly organoradionuclide complexes. Laboratory studies utilizing anion exchange chromatography have separated several anionically complexed radionuclides, e.g., 60 Co and 106 Ru, into a number of specific compounds or groups of compounds. Further identification of the anionic organoradionuclide complexes is planned utilizing high resolution mass spectrometry. Large-volume ultra-filtration experiments are characterizing the particulate forms of radionuclides being transported in these groundwaters

  6. Design solutions to interface flow problems. A review of groundwater flow and radionuclide migration along sealed radioactive waste repository tunnels. Final report

    International Nuclear Information System (INIS)

    1986-02-01

    All published proposals for the deep level burial of radioactive waste recognise that the access shafts, tunnels and boreholes must be sealed, and that the sealing of these openings plays an integral role in the overall isolation of the waste. Previous studies have identified the interface between the host ground formation and the various sealing materials as potential defects in the overall quality of the waste isolation. The significance of groundwater flow at and near the interface has been assessed for representative conditions in generic repository materials. A range of design options to minimise the significance of flow in the interface zone have been proposed, and the most practical of these options have been selected for quantitative analysis. It has been found that isolated high impermeability collars are of limited value unless a highly effective method of minimising ground disturbance during excavation can be developed. It has also been found that control of radionuclide migration by sorptive processes provides an attractive option. The effect of various geometrical arrangements of sorptive materials has been investigated. Consideration has also been given to the particular conditions in the near field, to the behaviour of weak plastic clay host formations and to the mechanical interaction between the backfill material and the host formation. (author)

  7. Influence of basalt/groundwater interactions on radionuclide migration

    International Nuclear Information System (INIS)

    Vandegrift, G.F.

    1984-01-01

    The work presented here is a partial summary of the experimental results obtained in the Laboratory Analog Program. Two aspects of this effort are (1) the interaction between simulated basaltic groundwater and basalt fissures that were either freshly cleaved or laboratory altered by hydrothermal treatment with the simulated groundwater and (2) the effect of this interaction on radionuclide migration through these basalt fissures. The following conclusions of this study bear heavily on the predicted safety of a basalt repository: Sorption properties of freshly fissured basalt and naturally aged basalt are quite different for different chemical species. Analog experiments predict that aged basalt would be an effective retarder of cesium, but would be much less so for actinide elements. Distribution ratios measured from batch experiments with finely ground rock samples (presenting unaltered rock surfaces) are not a reliable means of predicting radionuclide migration in geological repositories. As the near-repository area is resaturated by groundwater, its ability to retard actinide migration will be degraded with time. Disturbing the natural flow of groundwater through the repository area by constructing and backfilling the repository will modify the composition of groundwater. This modified groundwater is likely to interact with and to modify naturally aged basalt surfaces downstream from the repository

  8. Modeling Groundwater Flow and Transport of Radionuclides at Amchitka Island's Underground Nuclear Tests: Milrow, Long Shot, and Cannikin

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed Hassan; Karl Pohlmann; Jenny Chapman

    2002-11-19

    Since 1963, all United States nuclear tests have been conducted underground. A consequence of this testing has been the deposition of large amounts of radioactive material in the subsurface, sometimes in direct contact with groundwater. The majority of this testing occurred on the Nevada Test Site (NTS), but a limited number of experiments were conducted in other locations. One of these locations, Amchitka Island, Alaska is the subject of this report. Three underground nuclear tests were conducted on Amchitka Island. Long Shot was an 80-kiloton-yield test conducted at a depth of 700 meters (m) on October 29, 1965 (DOE, 2000). Milrow had an announced yield of about 1,000 kilotons, and was detonated at a depth of 1,220 m on October 2, 1969. Cannikin had an announced yield less than 5,000 kilotons, and was conducted at a depth of 1,790 m on November 6, 1971. The purpose of this work is to provide a portion of the information needed to conduct a human-health risk assessment of the potential hazard posed by the three underground nuclear tests on Amchitka Island. Specifically, the focus of this work is the subsurface transport portion, including the release of radionuclides from the underground cavities and their movement through the groundwater system to the point where they seep out of the ocean floor and into the marine environment. This requires a conceptual model of groundwater flow on the island using geologic, hydrologic, and chemical information, a numerical model for groundwater flow, a conceptual model of contaminant release and transport properties from the nuclear test cavities, and a numerical model for contaminant transport. Needed for the risk assessment are estimates of the quantity of radionuclides (in terms of mass flux) from the underground tests on Amchitka that could discharge to the ocean, the time of possible discharge, and the location in terms of distance from shoreline. The radionuclide data presented here are all reported in terms of normalized

  9. Deep groundwater flow at Palmottu

    International Nuclear Information System (INIS)

    Niini, H.; Vesterinen, M.; Tuokko, T.

    1993-01-01

    Further observations, measurements, and calculations aimed at determining the groundwater flow regimes and periodical variations in flow at deeper levels were carried out in the Lake Palmottu (a natural analogue study site for radioactive waste disposal in southwestern Finland) drainage basin. These water movements affect the migration of radionuclides from the Palmottu U-Th deposit. The deep water flow is essentially restricted to the bedrock fractures which developed under, and are still affected by, the stress state of the bedrock. Determination of the detailed variations was based on fracture-tectonic modelling of the 12 most significant underground water-flow channels that cross the surficial water of the Palmottu area. According to the direction of the hydraulic gradient the deep water flow is mostly outwards from the Palmottu catchment but in the westernmost section it is partly towards the centre. Estimation of the water flow through the U-Th deposit by the water-balance method is still only approximate and needs continued observation series and improved field measurements

  10. Radionuclide migration in groundwater. Annual progress report for 1982

    International Nuclear Information System (INIS)

    Robertson, D.E.; Toste, A.P.; Abel, K.H.; Brodzinski, R.L.

    1984-01-01

    Research has continued at a low-level waste disposal facility to characterize the physicochemical species of radionuclides migrating in groundwater. This facility consists of an unlined basin and connecting trench which receives effluent water containing low levels of a wide variety of fission and activation products and trace amounts of transuranic radionuclides. The effluent water percolates through the soil and a small fraction of it emerges at seepage springs located some 260 meters from the trench. The disposal basin and trench are very efficient in retaining most of the radionuclides, but trace amounts of a number of radionuclides existing in mobile chemical forms migrate in the groundwater from the trench to the springs. This facility provides the opportunity for characterizing the rates and mechanisms of radionuclide migration in groundwaters, identifying retardation processes, and validating geochemical models. 13 references, 25 figures, 23 tables

  11. Monitoring probe for groundwater flow

    Science.gov (United States)

    Looney, B.B.; Ballard, S.

    1994-08-23

    A monitoring probe for detecting groundwater migration is disclosed. The monitor features a cylinder made of a permeable membrane carrying an array of electrical conductivity sensors on its outer surface. The cylinder is filled with a fluid that has a conductivity different than the groundwater. The probe is placed in the ground at an area of interest to be monitored. The fluid, typically saltwater, diffuses through the permeable membrane into the groundwater. The flow of groundwater passing around the permeable membrane walls of the cylinder carries the conductive fluid in the same general direction and distorts the conductivity field measured by the sensors. The degree of distortion from top to bottom and around the probe is precisely related to the vertical and horizontal flow rates, respectively. The electrical conductivities measured by the sensors about the outer surface of the probe are analyzed to determine the rate and direction of the groundwater flow. 4 figs.

  12. A Hydrostratigraphic System for Modeling Groundwater Flow and Radionuclide Migration at the Corrective Action Unit Scale, Nevada Test Site and Surrounding Areas, Clark, Lincoln, and Nye Counties, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Prothro, Lance; Drellack Jr., Sigmund; Mercadante, Jennifer

    2009-01-31

    Underground Test Area (UGTA) corrective action unit (CAU) groundwater flow and contaminant transport models of the Nevada Test Site (NTS) and vicinity are built upon hydrostratigraphic framework models (HFMs) that utilize the hydrostratigraphic unit (HSU) as the fundamental modeling component. The delineation and three-dimensional (3-D) modeling of HSUs within the highly complex geologic terrain that is the NTS requires a hydrostratigraphic system that is internally consistent, yet flexible enough to account for overlapping model areas, varied geologic terrain, and the development of multiple alternative HFMs. The UGTA CAU-scale hydrostratigraphic system builds on more than 50 years of geologic and hydrologic work in the NTS region. It includes 76 HSUs developed from nearly 300 stratigraphic units that span more than 570 million years of geologic time, and includes rock units as diverse as marine carbonate and siliciclastic rocks, granitic intrusives, rhyolitic lavas and ash-flow tuffs, and alluvial valley-fill deposits. The UGTA CAU-scale hydrostratigraphic system uses a geology-based approach and two-level classification scheme. The first, or lowest, level of the hydrostratigraphic system is the hydrogeologic unit (HGU). Rocks in a model area are first classified as one of ten HGUs based on the rock’s ability to transmit groundwater (i.e., nature of their porosity and permeability), which at the NTS is mainly a function of the rock’s primary lithology, type and degree of postdepositional alteration, and propensity to fracture. The second, or highest, level within the UGTA CAU-scale hydrostratigraphic system is the HSU, which is the fundamental mapping/modeling unit within UGTA CAU-scale HFMs. HSUs are 3-D bodies that are represented in the finite element mesh for the UGTA groundwater modeling process. HSUs are defined systematically by stratigraphically organizing HGUs of similar character into larger HSUs designations. The careful integration of

  13. A Hydrostratigraphic System for Modeling Groundwater Flow and Radionuclide Migration at the Corrective Action Unit Scale, Nevada Test Site and Surrounding Areas, Clark, Lincoln, and Nye Counties, Nevada

    International Nuclear Information System (INIS)

    Prothro, Lance; Drellack Jr, Sigmund; Mercadante, Jennifer

    2009-01-01

    Underground Test Area (UGTA) corrective action unit (CAU) groundwater flow and contaminant transport models of the Nevada Test Site (NTS) and vicinity are built upon hydrostratigraphic framework models (HFMs) that utilize the hydrostratigraphic unit (HSU) as the fundamental modeling component. The delineation and three-dimensional (3-D) modeling of HSUs within the highly complex geologic terrain that is the NTS requires a hydrostratigraphic system that is internally consistent, yet flexible enough to account for overlapping model areas, varied geologic terrain, and the development of multiple alternative HFMs. The UGTA CAU-scale hydrostratigraphic system builds on more than 50 years of geologic and hydrologic work in the NTS region. It includes 76 HSUs developed from nearly 300 stratigraphic units that span more than 570 million years of geologic time, and includes rock units as diverse as marine carbonate and siliciclastic rocks, granitic intrusives, rhyolitic lavas and ash-flow tuffs, and alluvial valley-fill deposits. The UGTA CAU-scale hydrostratigraphic system uses a geology-based approach and two-level classification scheme. The first, or lowest, level of the hydrostratigraphic system is the hydrogeologic unit (HGU). Rocks in a model area are first classified as one of ten HGUs based on the rock's ability to transmit groundwater (i.e., nature of their porosity and permeability), which at the NTS is mainly a function of the rock's primary lithology, type and degree of postdepositional alteration, and propensity to fracture. The second, or highest, level within the UGTA CAU-scale hydrostratigraphic system is the HSU, which is the fundamental mapping/modeling unit within UGTA CAU-scale HFMs. HSUs are 3-D bodies that are represented in the finite element mesh for the UGTA groundwater modeling process. HSUs are defined systematically by stratigraphically organizing HGUs of similar character into larger HSUs designations. The careful integration of stratigraphic

  14. Study of groundwater colloids and their ability to transport radionuclides

    International Nuclear Information System (INIS)

    Tjus, K.; Wikberg, P.

    1987-03-01

    Natural occurring colloids in groundwater can adsorb and transport released radionuclides. In this work groundwater colloids have been investigated with zeta potential measurements and dynamic light scattering. The goal was i) to estimate the detection limits of the Institute's equipment for particle size estimation with dynamic light scattering and zeta potential with dynamic light scattering combined with estimation of Doppler shift in the scattered light frequency; ii) to examine several different groundwaters (Stripa, Kamlunge, Svartboberget). The possibility to apply a theoretical adsorption model for interpreting the results is also discussed. (orig.)

  15. Comparison of groundwater residence time using isotope techniques and numerical groundwater flow model in Gneissic Terrain, Korea

    International Nuclear Information System (INIS)

    Bae, D.S.; Kim, C.S.; Koh, Y.K.; Kim, K.S.; Song, M.Y.

    1997-01-01

    The prediction of groundwater flow affecting the migration of radionuclides is an important component of the performance assessment of radioactive waste disposal. Groundwater flow in fractured rock mass is controlled by fracture networks, transmissivity and hydraulic gradient. Furthermore the scale-dependent and anisotropic properties of hydraulic parameters are resulted mainly from irregular patterns of fracture system, which are very complex to evaluate properly with the current techniques available. For the purpose of characterizing a groundwater flow in fractured rock mass, the discrete fracture network (DFN) concept is available on the basis of assumptions of groundwater flowing only along fractures and flowpaths in rock mass formed by interconnected fractures. To increase the reliability of assessment in groundwater flow phenomena, numerical groundwater flow model and isotopic techniques were applied. Fracture mapping, borehole acoustic scanning were performed to identify conductive fractures in gneissic terrane. Tracer techniques, using deuterium, oxygen-18 and tritium were applied to evaluate the recharge area and groundwater residence time

  16. Hanford statewide groundwater flow and transport model calibration report

    International Nuclear Information System (INIS)

    Law, A.; Panday, S.; Denslow, C.; Fecht, K.; Knepp, A.

    1996-04-01

    This report presents the results of the development and calibration of a three-dimensional, finite element model (VAM3DCG) for the unconfined groundwater flow system at the Hanford Site. This flow system is the largest radioactively contaminated groundwater system in the United States. Eleven groundwater plumes have been identified containing organics, inorganics, and radionuclides. Because groundwater from the unconfined groundwater system flows into the Columbia River, the development of a groundwater flow model is essential to the long-term management of these plumes. Cost effective decision making requires the capability to predict the effectiveness of various remediation approaches. Some of the alternatives available to remediate groundwater include: pumping contaminated water from the ground for treatment with reinjection or to other disposal facilities; containment of plumes by means of impermeable walls, physical barriers, and hydraulic control measures; and, in some cases, management of groundwater via planned recharge and withdrawals. Implementation of these methods requires a knowledge of the groundwater flow system and how it responds to remedial actions

  17. Global scale groundwater flow model

    Science.gov (United States)

    Sutanudjaja, Edwin; de Graaf, Inge; van Beek, Ludovicus; Bierkens, Marc

    2013-04-01

    As the world's largest accessible source of freshwater, groundwater plays vital role in satisfying the basic needs of human society. It serves as a primary source of drinking water and supplies water for agricultural and industrial activities. During times of drought, groundwater sustains water flows in streams, rivers, lakes and wetlands, and thus supports ecosystem habitat and biodiversity, while its large natural storage provides a buffer against water shortages. Yet, the current generation of global scale hydrological models does not include a groundwater flow component that is a crucial part of the hydrological cycle and allows the simulation of groundwater head dynamics. In this study we present a steady-state MODFLOW (McDonald and Harbaugh, 1988) groundwater model on the global scale at 5 arc-minutes resolution. Aquifer schematization and properties of this groundwater model were developed from available global lithological model (e.g. Dürr et al., 2005; Gleeson et al., 2010; Hartmann and Moorsdorff, in press). We force the groundwtaer model with the output from the large-scale hydrological model PCR-GLOBWB (van Beek et al., 2011), specifically the long term net groundwater recharge and average surface water levels derived from routed channel discharge. We validated calculated groundwater heads and depths with available head observations, from different regions, including the North and South America and Western Europe. Our results show that it is feasible to build a relatively simple global scale groundwater model using existing information, and estimate water table depths within acceptable accuracy in many parts of the world.

  18. TRING: a computer program for calculating radionuclide transport in groundwater

    International Nuclear Information System (INIS)

    Maul, P.R.

    1984-12-01

    The computer program TRING is described which enables the transport of radionuclides in groundwater to be calculated for use in long term radiological assessments using methods described previously. Examples of the areas of application of the program are activity transport in groundwater associated with accidental spillage or leakage of activity, the shutdown of reactors subject to delayed decommissioning, shallow land burial of intermediate level waste and geologic disposal of high level waste. Some examples of the use of the program are given, together with full details to enable users to run the program. (author)

  19. Groundwater migration of radionuclides at Fermilab

    International Nuclear Information System (INIS)

    Malensek, A.J.; Wehmann, A.A.; Elwyn, A.J.; Moss, K.J.; Kesich, P.M.

    1993-01-01

    The simple Single Resident Well (SRW) Model has been used to calculate groundwater movement since Fermilab's inception. A new Concentration Model is proposed which is more realistic and takes advantage of computer modeling that has been developed for the siting of landfills. Site geologic and hydrologic data were given to a consultant who made the migration calculations from an initial concentration that was based upon the existing knowledge of the radioactivity leached out of the soil. The various components of the new Model are discussed, and numerical examples are given and compared with DOE/EPA limits

  20. Stochastic description of heterogeneities of permeability within groundwater flow models

    International Nuclear Information System (INIS)

    Cacas, M.C.; Lachassagne, P.; Ledoux, E.; Marsily, G. de

    1991-01-01

    In order to model radionuclide migration in the geosphere realistically at the field scale, the hydrogeologist needs to be able to simulate groundwater flow in heterogeneous media. Heterogeneity of the medium can be described using a stochastic approach, that affects the way in which a flow model is formulated. In this paper, we discuss the problems that we have encountered in modelling both continuous and fractured media. The stochastic approach leads to a methodology that enables local measurements of permeability to be integrated into a model which gives a good prediction of groundwater flow on a regional scale. 5 Figs.; 8 Refs

  1. Summary of the data which is used for radionuclide transport analysis in the groundwater

    International Nuclear Information System (INIS)

    Koga, Osamu; Nagara, Shuichi; Matsumura, Toshihiro; Takeuchi, Akira; Takeda, Shinji; Sato, Kazuhiko; Tokizawa, Takayuki

    2004-03-01

    To analyze high precision in groundwater flow and radionuclide transport around Yotsugi open-pit mining place site and around Yotsugi mill tailing yard, besides the topic in past analysis is extracted, following it did examination of the corresponding method and arrangement of physical properties value. It investigated concerning the 3-dimensional flow and transport analysis code which can handle the chain-radionuclide selected. The range of the analytical area examined that become the object of groundwater flow and transport analysis, the wide area, Yotsugi open-pit mining place site and Yotsugi mill tailing yard selected the analytical model area, concerning the range which is surrounded with the divide. Receiving the influence of the alteration zone and the crush zone concerning the coefficient of permeability of the granite, it re-appraised excluding the value which is supposed that water permeability is high. The weathered granite from the lithofacies divided in the high weathered granite and the low weathered granite. As for the geometrical mean of coefficient of permeability of the former 10 -6 m/s order, the later 10 -8 m/s order, there is a difference of 2 orders in both. In addition, the data which is obtained to this year concerning physical properties value for analysis, groundwater level, precipitation and radionuclide density etc. rearranged and data set drew up. (author)

  2. Modelling interaction of deep groundwaters with bentonite and radionuclide speciation

    International Nuclear Information System (INIS)

    Wanner, H.

    1986-04-01

    In the safety analysis recently reported for a potential Swiss high-level waste repository, radionuclide speciation and solubility limits are calculated for expected granitic groundwater conditions. This report describes a thermodynamic model which is used to estimate the chemical composition of the pore water in compacted sodium bentonite. The model is based on available experimental data and describes the basic reactions between bentonite and groundwater by an ion-exchange model for sodium, potassium, magnesium, and calcium. The model assumes equilibrium with calcite as long as sufficient carbonates remain in the bentonite, as well as quartz saturation. The long-term situation is modelled by the assumption that the near-field of a deep repository behaves like a mixing tank. It is found that sodium bentonite will slowly be converted to calcium bentonite. The modelled composition of the pore water of compacted sodium bentonite is used to estimate radionuclide solubilities in the near-field of a deep repository. The elements considered are: uranium, neptunium, plutonium, thorium, americium, and technetium. The redox potential in the near-field is assumed to be controlled by the corrosion products of the iron canister. Except for uranium and neptunium, radionuclide solubilities turn out to be lower under the modelled near-field conditions than in the groundwater of the surrounding granitic host rock. Uranium and neptunium solubility might be higher by orders of magnitude in the near-field than in the far-field. From the chemical point of view, calcium bentonite seems to be more stable than sodium bentonite in the presence of Swiss Reference Groundwater. The use of calcium bentonite instead of sodium bentonite will improve the reliability in the prediction of source terms for radionuclide transport in the geosphere. (author)

  3. Modelling interaction of deep groundwaters with bentonite and radionuclide speciation

    International Nuclear Information System (INIS)

    Wanner, H.

    1986-04-01

    In the safety analysis recently reported for a potential Swiss high-level waste repository, radionuclide speciation and solubility limits are calculated for expected granitic groundwater conditions. With the objective of deriving a more realistic description of radionuclide release from the near-field, an investigation has been initiated to quantitatively specify the chemistry of the near-field. In the Swiss case, the main components of the near-field are the glass waste-matrix, a thick steel canister horizontally emplaced in a drift, and a backfill of highly compacted sodium bentonite. This report describes a thermodynamic model which is used to estimate the chemical composition of the pore water in compacted sodium bentonite. Solubility limits and speciation of important actinides and the fission product technetium in the bentonite pore water are then calculated. The model is based on available experimental data on the interaction of sodium bentonite and groundwater and represents means of extrapolation from laboratory data to repository conditions. The modelled composition of the pore water of compacted sodium bentonite, as well as the various compositions resulting from the long-term extrapolation, are used to estimate radionuclide solubilities in the near-field of a deep repository. From the chemical point of view, calcium bentonite seems to be more stable than sodium bentonite in the presence of Swiss Reference Groundwater. Since the effect of calcium bentonite on the groundwater chemical composition will be considerably less marked than that of sodium bentonite, especially with respect to key parameters for the nuclide speciation like carbonate concentration and pH, the use of calcium bentonite instead of sodium bentonite will improve the reliability in the prediction of source terms for radionuclide transport in the geosphere. (author)

  4. Modeling groundwater flow on MPPs

    International Nuclear Information System (INIS)

    Ashby, S.F.; Falgout, R.D.; Smith, S.G.; Tompson, A.F.B.

    1993-10-01

    The numerical simulation of groundwater flow in three-dimensional heterogeneous porous media is examined. To enable detailed modeling of large contaminated sites, preconditioned iterative methods and massively parallel computing power are combined in a simulator called PARFLOW. After describing this portable and modular code, some numerical results are given, including one that demonstrates the code's scalability

  5. Modelling framework for groundwater flow at Sellafield

    International Nuclear Information System (INIS)

    Hooper, A.J.; Billington, D.E.; Herbert, A.W.

    1995-01-01

    The principal objective of Nirex is to develop a single deep geological repository for the safe disposal of low- and intermediate-level radioactive waste. In safety assessment, use is made of a variety of conceptual models that form the basis for modelling of the pathways by which radionuclides might return to the environment. In this paper, the development of a conceptual model for groundwater flow and transport through fractured rock on the various scales of interest is discussed. The approach is illustrated by considering how some aspects of the conceptual model are developed in particular numerical models. These representations of the conceptual model use fracture network geometries based on realistic rock properties. (author). refs., figs., tabs

  6. Modelling interaction of deep groundwaters with bentonite and radionuclide speciation

    International Nuclear Information System (INIS)

    Wanner, H.

    1986-04-01

    In the safety analysis recently reported for a potential Swiss high-level waste repository, radionuclide speciation and solubility limits are calculated for expected granitic groundwater conditions. With the objective of deriving a more realistic description of radionuclide release from the near-field, an investigation has been initiated to quantitatively specify the chemistry of the near-field. In the Swiss case, the main components of the near-field are the glass waste-matrix, a thick steel canister horizontally emplaced in a drift, and a backfill of highly compacted sodium bentonite. This report describes a thermodynamic model which is used to estimate the chemical composition of the pore water in compacted sodium bentonite. Solubility limits and speciation of important actinides and the fission product technetium in the bentonite pore water are then calculated. The model is based on available experimental data on the interaction of sodium bentonite and groundwater and represents means of extrapolation from laboratory data to repository conditions. The basic reactions between sodium bentonite and groundwater are described by an ion-exchange model for sodium, potassium, magnesium, and calcium. The model assumes equilibrium with calcite as long as sufficient carbonates remain in the bentonite, as well as quartz saturation. It is calculated that the pore water of compacted sodium bentonite saturated with Swiss Reference Groundwater will have a pH value of 9.7 and a free carbonate activity of 8x10 -4 M. The long-term situation is modelled by the assumption that the near-field of a deep repository behaves like a mixing tank. In this way, an attempt is made to account for the continuous water exchange between the near-field and the host rock. It is found that sodium bentonite will be slowly converted to calcium bentonite. This conversion is roughly estimated to be completed after 2 million years

  7. Modeling groundwater flow and quality

    Science.gov (United States)

    Konikow, Leonard F.; Glynn, Pierre D.; Selinus, Olle

    2013-01-01

    In most areas, rocks in the subsurface are saturated with water at relatively shallow depths. The top of the saturated zone—the water table—typically occurs anywhere from just below land surface to hundreds of feet below the land surface. Groundwater generally fills all pore spaces below the water table and is part of a continuous dynamic flow system, in which the fluid is moving at velocities ranging from feet per millennia to feet per day (Fig. 33.1). While the water is in close contact with the surfaces of various minerals in the rock material, geochemical interactions between the water and the rock can affect the chemical quality of the water, including pH, dissolved solids composition, and trace-elements content. Thus, flowing groundwater is a major mechanism for the transport of chemicals from buried rocks to the accessible environment, as well as a major pathway from rocks to human exposure and consumption. Because the mineral composition of rocks is highly variable, as is the solubility of various minerals, the human-health effects of groundwater consumption will be highly variable.

  8. Investigation and assessment of natural radionuclides in groundwater and geothermal fluid of Tianjin city

    International Nuclear Information System (INIS)

    Wang Xiao; Duan Xigui; Gao Liang; Yang Yuxin

    2012-01-01

    Investigation on the specific activities of natural radionuclides in the groundwater and geothermal fluids of Tianjin city were conducted. Based on the investigation, internal dose level posed by drinking the water and fluid to local public was evaluated. Results show the specific activities of natural radionuclides in the groundwater and geothermal fluid of Tianjin city is under control, no abnormal radioactivity discovered. (authors)

  9. Public Health Goal for Naturally Occurring Radionuclides in Groundwater

    International Nuclear Information System (INIS)

    Kamel, N.H.M.; Omar, H.A.; El-Baset, L.A.

    2008-01-01

    Naturally occurring and man-made radionuclide in groundwater may have a health hazardous to some residents. The objective of this work is to provide criteria for safety of drinking-water with respect to the chemical parameters and the radionuclide content. The annual effective dose for the consumption of drinking water was considered. Ground water samples were selected from different sites in Egypt, that have the most population, it were taken from aquifer regions along Giza sites in Egypt. Chemical analyses for the major anions, cations, and the radiological analyses were tested . Activity concentrations (Bq/l) of the gross alpha and the gross beta activities of our investigated samples were compared with the maximum contaminant level (MCL) of the world health organization (WHO). Some of the water samples were found to have a higher of gross beta and alpha particles than the MCL. Alpha activity were found depending on to the total dissolved solids (TDS) content of the water samples. Gamma activity concentrations were analyzed using low background germanium detector, the higher of activity values was found in some investigated samples is due to increasing of 226 Ra and 228 Ra activities. Tritium activity concentrations also were measured using soft beta liquid scintillation counter, it was found lower than the MCL. Our investigated samples were found to have a higher concentrations of the phosphate, nitrites, iron, and manganese contents than the maximum permissible limit, all the ground water samples were found to have a higher of silica and alumina content. Commercial carbon powder and natural clay materials were tested as ion exchangers for the removal of inorganic contaminants in the ground water samples. Clay materials was found to have a higher selectivity than activated carbon for the removal of radionuclides, phosphates, nitrites, and manganese content at the ground water samples

  10. Natural colloids in groundwater from granite and their potential impact on radionuclide transport

    International Nuclear Information System (INIS)

    Vilks, P.; Bachinski, D.B.

    1997-03-01

    AECL has submitted an Environmental Impact Statement (EIS) to evaluate the concept of nuclear fuel disposal at depth in crystalline rock of the Canadian Shield. As part of geochemical studies carried out in support of the EIS, the role of natural groundwater colloids (0.001 to 0.45 μm) and suspended particles (>0.45 μm) in radionuclide transport in granite rock has been investigated. This report summarizes the results of investigations carried out in groundwaters from the Whiteshell Research Area (WRA) of southern Manitoba and the Atikokan Research Area (ARA) of northwestern Ontario to determine the concentrations, size distributions, and compositions of natural particles in groundwaters from the Canadian Shield. Particles from groundwater were isolated by ultrafiltration under a nitrogen atmosphere and particle concentrations and size distributions were determined by filtration, and by laser-based particle counting and size analysis. Groundwaters from Canadian Shield granites contain particles in a broad range of sizes, with no one particular size being dominant. Particle compositions include aluminosilicates, Fe oxides, carbonate and organics. Suspended particles are most likely generated by the mobilization of fracture-lining minerals by groundwater flow, while colloids are formed by a combination of precipitation and mobilization of colloidal material from fracture surfaces. The average concentration of 0.01 to 0.45 μm colloids in WRA groundwaters was 1.05 ± 0.14 mg/L. Average colloid concentrations were slightly higher in the more highly fractured ARA, although the highest observed colloid concentration in the ARA was below the 7 mg/L maximum observed in a sample from the WRA. The existence of colloids in the 0.001 to 0.01 μm size range was demonstrated using the results of chemical analysis of particle concentrates and data obtained with the laser-based Ultrafine Particle Size Analyzer (UPA). The WRA groundwaters contain on average about 2.7 mg/L of 0

  11. Uncertainties in geologic disposal of high-level wastes - groundwater transport of radionuclides and radiological consequences

    International Nuclear Information System (INIS)

    Kocher, D.C.; Sjoreen, A.L.; Bard, C.S.

    1983-01-01

    The analysis for radionuclide transport in groundwater considers models and methods for characterizing (1) the present geologic environment and its future evolution due to natural geologic processes and to repository development and waste emplacement, (2) groundwater hydrology, (3) radionuclide geochemistry, and (4) the interactions among these phenomena. The discussion of groundwater transport focuses on the nature of the sources of uncertainty rather than on quantitative estimates of their magnitude, because of the lack of evidence that current models can provide realistic quantitative predictions of radionuclide transport in groundwater for expected repository environments. The analysis for the long-term health risk to man following releases of long-lived radionuclides to the biosphere is more quantitative and involves estimates of uncertainties in (1) radionuclide concentrations in man's exposure environment, (2) radionuclide intake by exposed individuals per unit concentration in the environment, (3) the dose per unit intake, (4) the number of exposed individuals, and (5) the health risk per unit dose. For the important long-lived radionuclides in high-level waste, uncertainties in most of the different components of a calculation of individual and collective dose per unit release appear to be no more than two or three orders of magnitude; these uncertainties are certainly much less than uncertainties in predicting groundwater transport of radionuclides between a repository and the biosphere. Several limitations in current models for predicting the health risk to man per unit release to the biosphere are discussed

  12. Radionuclide inventories for the F- and H-area seepage basin groundwater plumes

    Energy Technology Data Exchange (ETDEWEB)

    Hiergesell, Robert A [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Kubilius, Walter P. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-05-01

    Within the General Separations Areas (GSA) at the Savannah River Site (SRS), significant inventories of radionuclides exist within two major groundwater contamination plumes that are emanating from the F- and H-Area seepage basins. These radionuclides are moving slowly with groundwater migration, albeit more slowly due to interaction with the soil and aquifer matrix material. The purpose of this investigation is to quantify the activity of radionuclides associated with the pore water component of the groundwater plumes. The scope of this effort included evaluation of all groundwater sample analyses obtained from the wells that have been established by the Environmental Compliance & Area Completion Projects (EC&ACP) Department at SRS to monitor groundwater contamination emanating from the F- and H-Area Seepage Basins. Using this data, generalized groundwater plume maps for the radionuclides that occur in elevated concentrations (Am-241, Cm-243/244, Cs-137, I-129, Ni-63, Ra-226/228, Sr-90, Tc-99, U-233/234, U-235 and U-238) were generated and utilized to calculate both the volume of contaminated groundwater and the representative concentration of each radionuclide associated with different plume concentration zones.

  13. A model of accumulation of radionuclides in biosphere originating from groundwater contamination

    Energy Technology Data Exchange (ETDEWEB)

    Gaerdenaes, Annemieke [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Soil Sciences; Jansson, Per-Erik; Karlberg, Louise [Royal Inst. of Technology, Stockholm (Sweden). Dept. Land and Water Resources

    2006-03-15

    The objective of this study is to introduce a module in CoupModel describing the transport and accumulation in the biosphere of a radionuclide originating from a ground water contamination. Two model approaches describing the plant uptake of a radionuclide were included, namely passive and active uptake. Passive uptake means in this study that the root uptake rate of a radionuclide is governed by water uptake. Normal mechanism for the passive water uptake is the convective flux of water from the soil to the plant. An example of element taken up passively is Ca. Active plant uptake is in this model defined as the root uptake rate of a radionuclide that is governed by carbon assimilation i.e. photosynthesis and plant growth. The actively taken up element can for example be an element essential to plant, but not available in high enough concentration by passive uptake alone, like the major nutrients N and P or an element that very well resembles a plant nutrient, like Cs resembles K. Active uptake of trace element may occur alone or in addition to passive uptake. Normal mechanism for the active uptake is molecular diffusion from the soil solution to the roots or via any other organism living in symbiosis with the roots like the mycorrhiza. Also a model approach describing adsorption was introduced. CoupModel dynamically couples and simulates the flows of water, heat, carbon and nitrogen in the soil/plant/atmosphere system. Any number of plants may be defined and are divided into roots, leaves, stem and grain. The soil is considered in one vertical profile that may be represented into a maximum of 100 layers. The model is the windows-successor and integrated version of the DOS-models SOIL and SOILN, which have been widely used on different ecosystems and climate regions during 25 years time period. To this soil/plant/atmosphere model were introduced a module describing accumulation of a radionuclide in the biosphere originating from groundwater contamination. The

  14. A model of accumulation of radionuclides in biosphere originating from groundwater contamination

    International Nuclear Information System (INIS)

    Gaerdenaes, Annemieke; Jansson, Per-Erik; Karlberg, Louise

    2006-03-01

    The objective of this study is to introduce a module in CoupModel describing the transport and accumulation in the biosphere of a radionuclide originating from a ground water contamination. Two model approaches describing the plant uptake of a radionuclide were included, namely passive and active uptake. Passive uptake means in this study that the root uptake rate of a radionuclide is governed by water uptake. Normal mechanism for the passive water uptake is the convective flux of water from the soil to the plant. An example of element taken up passively is Ca. Active plant uptake is in this model defined as the root uptake rate of a radionuclide that is governed by carbon assimilation i.e. photosynthesis and plant growth. The actively taken up element can for example be an element essential to plant, but not available in high enough concentration by passive uptake alone, like the major nutrients N and P or an element that very well resembles a plant nutrient, like Cs resembles K. Active uptake of trace element may occur alone or in addition to passive uptake. Normal mechanism for the active uptake is molecular diffusion from the soil solution to the roots or via any other organism living in symbiosis with the roots like the mycorrhiza. Also a model approach describing adsorption was introduced. CoupModel dynamically couples and simulates the flows of water, heat, carbon and nitrogen in the soil/plant/atmosphere system. Any number of plants may be defined and are divided into roots, leaves, stem and grain. The soil is considered in one vertical profile that may be represented into a maximum of 100 layers. The model is the windows-successor and integrated version of the DOS-models SOIL and SOILN, which have been widely used on different ecosystems and climate regions during 25 years time period. To this soil/plant/atmosphere model were introduced a module describing accumulation of a radionuclide in the biosphere originating from groundwater contamination. The

  15. Radionuclide transfer onto ground surface in surface water flow, 1

    International Nuclear Information System (INIS)

    Mukai, Masayuki; Takebe, Shinichi; Komiya, Tomokazu; Kamiyama, Hideo

    1991-07-01

    Radionuclides migration in ground surface water flow is considered to be one of the important path way in the scenario for environmental migration of radionuclides leaked from low level radioactive waste repository. Simulating the slightly sloped surface on which contaminated solution is flowing downward, testing for radionuclide migration on ground surface had been started. As it's first step, an experiment was carried out under the condition of restricted infiltration in order to elucidate the adsorption behavior of radionuclides onto the loamy soil surface in related with hydraulic conditions. Radionuclides concentration change in effluent solution with time and a concentration distribution of radionuclides adsorbed on the ground surface were obtained from several experimental conditions combining the rate and the duration time of the water flow. The radionuclides concentration in the effluent solution was nearly constant during each experimental period, and was reduced under the condition of lower flow rate. The surface distribution of radionuclides concentration showed two distinctive regions. The one was near the inlet vessel where the concentration was promptly reducing, and the other was following the former where the concentration was nearly constant. The characteristic surface distribution of radionuclides concentration can be explained by a two dimensional diffusion model with a first order adsorption reaction, based on the advection of flow rate distribution in perpendicular direction. (author)

  16. Revised conceptualization of the North China Basin groundwater flow system: Groundwater age, heat and flow simulations

    Science.gov (United States)

    Cao, Guoliang; Han, Dongmei; Currell, Matthew J.; Zheng, Chunmiao

    2016-09-01

    Groundwater flow in deep sedimentary basins results from complex evolution processes on geological timescales. Groundwater flow systems conceptualized according to topography and/or groundwater table configuration generally assume a near-equilibrium state with the modern landscape. However, the time to reach such a steady state, and more generally the timescales of groundwater flow system evolution are key considerations for large sedimentary basins. This is true in the North China Basin (NCB), which has been studied for many years due to its importance as a groundwater supply. Despite many years of study, there remain contradictions between the generally accepted conceptual model of regional flow, and environmental tracer data. We seek to reconcile these contractions by conducting simulations of groundwater flow, age and heat transport in a three dimensional model, using an alternative conceptual model, based on geological, thermal, isotope and historical data. We infer flow patterns under modern hydraulic conditions using this new model and present the theoretical maximum groundwater ages under such a flow regime. The model results show that in contrast to previously accepted conceptualizations, most groundwater is discharged in the vicinity of the break-in-slope of topography at the boundary between the piedmont and central plain. Groundwater discharge to the ocean is in contrast small, and in general there are low rates of active flow in the eastern parts of the basin below the central and coastal plain. This conceptualization is more compatible with geochemical and geothermal data than the previous model. Simulated maximum groundwater ages of ∼1 Myrs below the central and coastal plain indicate that residual groundwater may be retained in the deep parts of the basin since being recharged during the last glacial period or earlier. The groundwater flow system has therefore probably not reached a new equilibrium state with modern-day hydraulic conditions. The

  17. Numerical simulation of groundwater flow in LILW Repository site:I. Groundwater flow modeling

    Energy Technology Data Exchange (ETDEWEB)

    Park, Koung Woo; Ji, Sung Hoon; Kim, Chun Soo; Kim, Kyoung Su [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Ji Yeon [Korea Hydro and Nuclear Power Co. Ltd., Seoul (Korea, Republic of)

    2008-12-15

    Based on the site characterization works in a low and intermediate level waste (LILW) repository site, the numerical simulations for groundwater flow were carried out in order to understand the groundwater flow system of repository site. To accomplish the groundwater flow modeling in the repository site, the discrete fracture network (DFN) model was constructed using the characteristics of fracture zones and background fractures. At result, the total 10 different hydraulic conductivity(K) fields were obtained from DFN model stochastically and K distributions of constructed mesh were inputted into the 10 cases of groundwater flow simulations in FEFLOW. From the total 10 numerical simulation results, the simulated groundwater levels were strongly governed by topography and the groundwater fluxes were governed by locally existed high permeable fracture zones in repository depth. Especially, the groundwater table was predicted to have several tens meters below the groundwater table compared with the undisturbed condition around disposal silo after construction of underground facilities. After closure of disposal facilities, the groundwater level would be almost recovered within 1 year and have a tendency to keep a steady state of groundwater level in 2 year.

  18. Evaluating groundwater flow using passive electrical measurements

    Science.gov (United States)

    Voytek, E.; Revil, A.; Singha, K.

    2016-12-01

    Accurate quantification of groundwater flow patterns, both in magnitude and direction, is a necessary component of evaluating any hydrologic system. Groundwater flow patterns are often determined using a dense network of wells or piezometers, which can be limited due to logistical or regulatory constraints. The self-potential (SP) method, a passive geophysical technique that relies on currents generated by water movement through porous materials, is a re-emerging alternative or addition to traditional piezometer networks. Naturally generated currents can be measured as voltage differences at the ground surface using only two electrodes, or a more complex electrode array. While the association between SP measurements and groundwater flow was observed as early as 1890s, the method has seen resurgence in hydrology since the governing equations were refined in the 1980s. The method can be used to analyze hydrologic processes at various temporal and spatial scales. Here we present the results of multiple SP surveys collected a multiple scales (1 to 10s of meters). Here single SP grid surveys are used to evaluate flow patterns through artic hillslopes at a discrete point in time. Additionally, a coupled groundwater and electrical model is used to analyze multiple SP data sets to evaluate seasonal changes in groundwater flow through an alpine meadow.

  19. Site scale groundwater flow in Haestholmen

    Energy Technology Data Exchange (ETDEWEB)

    Loefman, J. [VTT Energy, Espoo (Finland)

    1999-05-01

    Groundwater flow modelling on the site scale has been an essential part of site investigation work carried out at different locations since 1986. The objective of the modelling has been to provide results that characterise the groundwater flow conditions deep in the bedrock. The main result quantities can be used for evaluation of the investigation sites and of the preconditions for safe final disposal - of spent nuclear fuel. This study represents the groundwater flow modelling at Haestholmen, and it comprises the transient flow analysis taking into account the effects of density variations and the repository as well as the post-glacial land uplift. The analysis is performed by means of numerical finite element simulation of coupled and transient groundwater flow and solute transport carried out up to 10000 years into the future. This work provides also the results for the site-specific data needs for the block scale groundwater flow modelling at Haestholmen. Conceptually the fractured bedrock is divided into hydraulic units: the planar fracture zones and the remaining part of the bedrock. The equivalent-continuum (EC) model is applied so that each hydraulic unit is treated as a homogeneous and isotropic continuum with representative average characteristics. All the fracture zones are modelled explicitly and represented by two-dimensional finite elements. A site-specific simulation model for groundwater flow and solute transport is developed on the basis of the latest hydrogeological and hydrogeochemical field investigations at Haestholmen. The present topography together with a mathematical model describing the land uplift at the Haestholmen area are employed as a boundary condition at the surface of the model. The overall flow pattern is mostly controlled by the local variations in the topography and by the highly transmissive fracture zones. Near the surface the flow spreads out to offshore and to the lower areas of topography in all directions away from

  20. Site scale groundwater flow in Haestholmen

    International Nuclear Information System (INIS)

    Loefman, J.

    1999-05-01

    Groundwater flow modelling on the site scale has been an essential part of site investigation work carried out at different locations since 1986. The objective of the modelling has been to provide results that characterise the groundwater flow conditions deep in the bedrock. The main result quantities can be used for evaluation of the investigation sites and of the preconditions for safe final disposal - of spent nuclear fuel. This study represents the groundwater flow modelling at Haestholmen, and it comprises the transient flow analysis taking into account the effects of density variations and the repository as well as the post-glacial land uplift. The analysis is performed by means of numerical finite element simulation of coupled and transient groundwater flow and solute transport carried out up to 10000 years into the future. This work provides also the results for the site-specific data needs for the block scale groundwater flow modelling at Haestholmen. Conceptually the fractured bedrock is divided into hydraulic units: the planar fracture zones and the remaining part of the bedrock. The equivalent-continuum (EC) model is applied so that each hydraulic unit is treated as a homogeneous and isotropic continuum with representative average characteristics. All the fracture zones are modelled explicitly and represented by two-dimensional finite elements. A site-specific simulation model for groundwater flow and solute transport is developed on the basis of the latest hydrogeological and hydrogeochemical field investigations at Haestholmen. The present topography together with a mathematical model describing the land uplift at the Haestholmen area are employed as a boundary condition at the surface of the model. The overall flow pattern is mostly controlled by the local variations in the topography and by the highly transmissive fracture zones. Near the surface the flow spreads out to offshore and to the lower areas of topography in all directions away from

  1. Regression modeling of ground-water flow

    Science.gov (United States)

    Cooley, R.L.; Naff, R.L.

    1985-01-01

    Nonlinear multiple regression methods are developed to model and analyze groundwater flow systems. Complete descriptions of regression methodology as applied to groundwater flow models allow scientists and engineers engaged in flow modeling to apply the methods to a wide range of problems. Organization of the text proceeds from an introduction that discusses the general topic of groundwater flow modeling, to a review of basic statistics necessary to properly apply regression techniques, and then to the main topic: exposition and use of linear and nonlinear regression to model groundwater flow. Statistical procedures are given to analyze and use the regression models. A number of exercises and answers are included to exercise the student on nearly all the methods that are presented for modeling and statistical analysis. Three computer programs implement the more complex methods. These three are a general two-dimensional, steady-state regression model for flow in an anisotropic, heterogeneous porous medium, a program to calculate a measure of model nonlinearity with respect to the regression parameters, and a program to analyze model errors in computed dependent variables such as hydraulic head. (USGS)

  2. Numerical models of groundwater flow and transport

    International Nuclear Information System (INIS)

    Konikow, L.F.

    1996-01-01

    This chapter reviews the state-of-the-art in deterministic modeling of groundwater flow and transport processes, which can be used for interpretation of isotope data through groundwater flow analyses. Numerical models which are available for this purpose are described and their applications to complex field problems are discussed. The theoretical bases of deterministic modeling are summarized, and advantages and limitations of numerical models are described. The selection of models for specific applications and their calibration procedures are described, and results of a few illustrative case study type applications are provided. (author). 145 refs, 17 figs, 2 tabs

  3. Numerical models of groundwater flow and transport

    Energy Technology Data Exchange (ETDEWEB)

    Konikow, L F [Geological Survey, Reston, VA (United States)

    1996-10-01

    This chapter reviews the state-of-the-art in deterministic modeling of groundwater flow and transport processes, which can be used for interpretation of isotope data through groundwater flow analyses. Numerical models which are available for this purpose are described and their applications to complex field problems are discussed. The theoretical bases of deterministic modeling are summarized, and advantages and limitations of numerical models are described. The selection of models for specific applications and their calibration procedures are described, and results of a few illustrative case study type applications are provided. (author). 145 refs, 17 figs, 2 tabs.

  4. Analysis of groundwater flow beneath ice sheets

    Energy Technology Data Exchange (ETDEWEB)

    Boulton, G. S.; Zatsepin, S.; Maillot, B. [Univ. of Edinburgh (United Kingdom). Dept. of Geology and Geophysics

    2001-03-01

    The large-scale pattern of subglacial groundwater flow beneath European ice sheets was analysed in a previous report. It was based on a two-dimensional flowline model. In this report, the analysis is extended to three dimensions by exploring the interactions between groundwater and tunnel flow. A theory is developed which suggests that the large-scale geometry of the hydraulic system beneath an ice sheet is a coupled, self-organising system. In this system the pressure distribution along tunnels is a function of discharge derived from basal meltwater delivered to tunnels by groundwater flow, and the pressure along tunnels itself sets the base pressure which determines the geometry of catchments and flow towards the tunnel. The large-scale geometry of tunnel distribution is a product of the pattern of basal meltwater production and the transmissive properties of the bed. The tunnel discharge from the ice margin of the glacier, its seasonal fluctuation and the sedimentary characteristics of eskers are largely determined by the discharge of surface meltwater which penetrates to the bed in the terminal zone. The theory explains many of the characteristics of esker systems and can account for tunnel valleys. It is concluded that the large-scale hydraulic regime beneath ice sheets is largely a consequence of groundwater/tunnel flow interactions and that it is essential similar to non-glacial hydraulic regimes. Experimental data from an Icelandic glacier, which demonstrates measured relationships between subglacial tunnel flow and groundwater flow during the transition from summer to winter seasons for a modern glacier, and which support the general conclusions of the theory is summarised in an appendix.

  5. Analysis of groundwater flow beneath ice sheets

    International Nuclear Information System (INIS)

    Boulton, G. S.; Zatsepin, S.; Maillot, B.

    2001-03-01

    The large-scale pattern of subglacial groundwater flow beneath European ice sheets was analysed in a previous report. It was based on a two-dimensional flowline model. In this report, the analysis is extended to three dimensions by exploring the interactions between groundwater and tunnel flow. A theory is developed which suggests that the large-scale geometry of the hydraulic system beneath an ice sheet is a coupled, self-organising system. In this system the pressure distribution along tunnels is a function of discharge derived from basal meltwater delivered to tunnels by groundwater flow, and the pressure along tunnels itself sets the base pressure which determines the geometry of catchments and flow towards the tunnel. The large-scale geometry of tunnel distribution is a product of the pattern of basal meltwater production and the transmissive properties of the bed. The tunnel discharge from the ice margin of the glacier, its seasonal fluctuation and the sedimentary characteristics of eskers are largely determined by the discharge of surface meltwater which penetrates to the bed in the terminal zone. The theory explains many of the characteristics of esker systems and can account for tunnel valleys. It is concluded that the large-scale hydraulic regime beneath ice sheets is largely a consequence of groundwater/tunnel flow interactions and that it is essential similar to non-glacial hydraulic regimes. Experimental data from an Icelandic glacier, which demonstrates measured relationships between subglacial tunnel flow and groundwater flow during the transition from summer to winter seasons for a modern glacier, and which support the general conclusions of the theory is summarised in an appendix

  6. Effect of reducing groundwater on the retardation of redox-sensitive radionuclides

    Directory of Open Access Journals (Sweden)

    Rose TP

    2008-12-01

    Full Text Available Abstract Laboratory batch sorption experiments were used to investigate variations in the retardation behavior of redox-sensitive radionuclides. Water-rock compositions were designed to simulate subsurface conditions at the Nevada Test Site (NTS, where a suite of radionuclides were deposited as a result of underground nuclear testing. Experimental redox conditions were controlled by varying the oxygen content inside an enclosed glove box and by adding reductants into the testing solutions. Under atmospheric (oxidizing conditions, radionuclide distribution coefficients varied with the mineralogic composition of the sorbent and the water chemistry. Under reducing conditions, distribution coefficients showed marked increases for 99Tc (from 1.22 at oxidizing to 378 mL/g at mildly reducing conditions and 237Np (an increase from 4.6 to 930 mL/g in devitrified tuff, but much smaller variations in alluvium, carbonate rock, and zeolitic tuff. This effect was particularly important for 99Tc, which tends to be mobile under oxidizing conditions. A review of the literature suggests that iodine sorption should decrease under reducing conditions when I- is the predominant species; this was not consistently observed in batch tests. Overall, sorption of U to alluvium, devitrified tuff, and zeolitic tuff under atmospheric conditions was less than in the glove-box tests. However, the mildly reducing conditions achieved here were not likely to result in substantial U(VI reduction to U(IV. Sorption of Pu was not affected by the decreasing Eh conditions achieved in this study, as the predominant sorbed Pu species in all conditions was expected to be the low-solubility and strongly sorbing Pu(OH4. Depending on the aquifer lithology, the occurrence of reducing conditions along a groundwater flowpath could potentially contribute to the retardation of redox-sensitive radionuclides 99Tc and 237Np, which are commonly identified as long-term dose contributors in the risk

  7. Geomorphic aspects of groundwater flow

    Science.gov (United States)

    LaFleur, Robert G.

    The many roles that groundwater plays in landscape evolution are becoming more widely appreciated. In this overview, three major categories of groundwater processes and resulting landforms are considered: (1) Dissolution creates various karst geometries, mainly in carbonate rocks, in response to conditions of recharge, geologic setting, lithology, and groundwater circulation. Denudation and cave formation rates can be estimated from kinetic and hydraulic parameters. (2) Groundwater weathering generates regoliths of residual alteration products at weathering fronts, and subsequent exhumation exposes corestones, flared slopes, balanced rocks, domed inselbergs, and etchplains of regional importance. Groundwater relocation of dissolved salts creates duricrusts of various compositions, which become landforms. (3) Soil and rock erosion by groundwater processes include piping, seepage erosion, and sapping, important agents in slope retreat and headward gully migration. Thresholds and limits are important in many chemical and mechanical groundwater actions. A quantitative, morphometric approach to groundwater landforms and processes is exemplified by selected studies in carbonate and clastic terrains of ancient and recent origins. Résumé Les rôles variés joués par les eaux souterraines dans l'évolution des paysages deviennent nettement mieux connus. La revue faite ici prend en considération trois grandes catégories de processus liés aux eaux souterraines et les formes associées: (1) La dissolution crée des formes karstiques variées, surtout dans les roches carbonatées, en fonction des conditions d'alimentation, du cadre géologique, de la lithologie et de la circulation des eaux souterraines. Les taux d'érosion et de formation des grottes peuvent être estimés à partir de paramètres cinétiques et hydrauliques. (2) L'érosion par les eaux souterraines donne naissance à des régolites, résidus d'altération sur des fronts d'altération, et l'exhumation r

  8. Colloid migration in groundwaters: Geochemical interactions of radionuclides with natural colloids. Final report

    International Nuclear Information System (INIS)

    Kim, J.J.; Longworth, G.; Hasler, S.E.; Gardiner, M.; Fritz, P.; Klotz, D.; Lazik, D.; Wolf, M.; Geyer, S.; Alexander, J.L.; Read, D.; Thomas, J.B.

    1994-08-01

    In this joint research programme the significance of groundwater colloids in far field radionuclide migration has been studied. The characterization, quantification and theoretical interpretation of colloid-borne transport phenomena for radionuclides were the main objectives of this research programme. Groundwaters, colloids and sediments were sampled from aquifer system overlying a saltdome in the Gorleben area in northern Germany and were characterized by various analytical methods (ICP-MS, ICP-AES, neutron activation analysis (NAA), DOC-Analyser, HPIC, potentiometric titration). Different natural isotopes ( 2 H, 3 H, 13 C, 14 C, 18 O, 34 S, U/Th decay series) were determined and their ratios were compared with one another in the order to ascertain the provenance of the groundwater colloids. The investigated groundwaters contain substantial amounts of colloids mainly composed of humic and fulvic acids loaded with various metal ions. The chemical interaction of radionuclide ions of various oxidation states (Am, Eu, for M(III), Th, Pu for M(IV), Np for M(V) and U for M(VI)) with groundwater colloids was investigated in order to elucidate the colloid facilitated migration behaviour of actinides in a given aquifer system. Transport process studies with generated pseudocolloids of radionuclides in various oxidation states were undertaken in scaled column experiments, pre-equilibrated with colloid rich Gorleben groundwater. A modelling programme was developed to predict chemical transport of radionuclides in the presence of humic colloids using a modified version of the CHEMTARD code. Modelling predictions have generated acceptable results for Eu, Am and U and poorer agreement between experimental and modelling results for Th and Np as a result of more limited data. (orig.)

  9. Colloid migration in groundwaters: Geochemical interactions of radionuclides with natural colloids. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J.J. [Technische Univ. Muenchen, Garching (Germany). Inst. fuer Radiochemie; Delakowitz, B. [Technische Univ. Muenchen, Garching (Germany). Inst. fuer Radiochemie; Zeh, P. [Technische Univ. Muenchen, Garching (Germany). Inst. fuer Radiochemie; Probst, T. [Technische Univ. Muenchen, Garching (Germany). Inst. fuer Radiochemie; Lin, X. [Technische Univ. Muenchen, Garching (Germany). Inst. fuer Radiochemie; Ehrlicher, U. [Technische Univ. Muenchen, Garching (Germany). Inst. fuer Radiochemie; Schauer, C. [Technische Univ. Muenchen, Garching (Germany). Inst. fuer Radiochemie; Ivanovich, M. [AEA Environment and Energy, Harwell (United Kingdom); Longworth, G. [AEA Environment and Energy, Harwell (United Kingdom); Hasler, S.E. [AEA Environment and Energy, Harwell (United Kingdom); Gardiner, M. [AEA Decommissioning and Radwaste, Harwell (United Kingdom); Fritz, P. [Gesellschaft fuer Strahlen- und Umweltforschung mbH Muenchen, Neuherberg (Germany); Klotz, D. [Gesellschaft fuer Strahlen- und Umweltforschung mbH Muenchen, Neuherberg (Germany); Lazik, D. [Gesellschaft fuer Strahlen- und Umweltforschung mbH Muenchen, Neuherberg (Germany); Wolf, M. [Gesellschaft fuer Strahlen- und Umweltforschung mbH Muenchen, Neuherberg (Germany); Geyer, S. [Gesellschaft fuer Strahlen- und Umweltforschung mbH Muenchen, Neuherberg (Germany); Alexander, J.L. [Atkins (W.S.) Engineering Sciences, Epsom (United Kingdom); Read, D. [Atkins (W.S.) Engineering Sciences, Epsom (United Kingdom); Thomas, J.B. [Atkins (W.S.) Engineering Sciences, Epsom (United Kingdom)

    1994-08-01

    In this joint research programme the significance of groundwater colloids in far field radionuclide migration has been studied. The characterization, quantification and theoretical interpretation of colloid-borne transport phenomena for radionuclides were the main objectives of this research programme. Groundwaters, colloids and sediments were sampled from aquifer system overlying a saltdome in the Gorleben area in northern Germany and were characterized by various analytical methods (ICP-MS, ICP-AES, neutron activation analysis (NAA), DOC-Analyser, HPIC, potentiometric titration). Different natural isotopes ({sup 2}H, {sup 3}H, {sup 13}C, {sup 14}C, {sup 18}O, {sup 34}S, U/Th decay series) were determined and their ratios were compared with one another in the order to ascertain the provenance of the groundwater colloids. The investigated groundwaters contain substantial amounts of colloids mainly composed of humic and fulvic acids loaded with various metal ions. The chemical interaction of radionuclide ions of various oxidation states (Am, Eu, for M(III), Th, Pu for M(IV), Np for M(V) and U for M(VI)) with groundwater colloids was investigated in order to elucidate the colloid facilitated migration behaviour of actinides in a given aquifer system. Transport process studies with generated pseudocolloids of radionuclides in various oxidation states were undertaken in scaled column experiments, pre-equilibrated with colloid rich Gorleben groundwater. A modelling programme was developed to predict chemical transport of radionuclides in the presence of humic colloids using a modified version of the CHEMTARD code. Modelling predictions have generated acceptable results for Eu, Am and U and poorer agreement between experimental and modelling results for Th and Np as a result of more limited data. (orig.)

  10. Limitations of radionuclide flow studies in bilateral carotid thrombosis

    International Nuclear Information System (INIS)

    Messert, B.; Tyson, I.B.; Barron, S.A.

    1975-01-01

    Radionuclide angiography as a noninvasive procedure has become an important tool in the evaluation of cerebrovascular diseases. Determinations of arm-to-brain circulation times complemented by the transit times of the radionuclide bolus through the brain afford insight into the functional status of the vascular system of the brain. Delays in perfusion, asymmetries in appearance, and washout of the radionuclide material can be correlated with disease entities. However, as with many procedures elevated to the status of a screening test, the possibility of false-positive and false-negative results exists. Two cases of bilateral carotid occlusion are presented, showing normal or only delayed, fairly symmetrical brain perfusion. The appearance of the radionuclide flow in the neck in AP and lateral views gave no suggestion of the involved deficits. Even multiple-projection imaging might fail to demonstrate major vascular obstructions. However, attentive study of these projections might yield interesting evidence of unexpected collateral flow systems. (U.S.)

  11. Sensitivity studies of unsaturated groundwater flow modeling for groundwater travel time calculations at Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Altman, S.J.; Ho, C.K.; Arnold, B.W.; McKenna, S.A.

    1995-01-01

    Unsaturated flow has been modeled through four cross-sections at Yucca Mountain, Nevada, for the purpose of determining groundwater particle travel times from the potential repository to the water table. This work will be combined with the results of flow modeling in the saturated zone for the purpose of evaluating the suitability of the potential repository under the criteria of 10CFR960. One criterion states, in part, that the groundwater travel time (GWTT) from the repository to the accessible environment must exceed 1,000 years along the fastest path of likely and significant radionuclide travel. Sensitivity analyses have been conducted for one geostatistical realization of one cross-section for the purpose of (1) evaluating the importance of hydrological parameters having some uncertainty and (2) examining conceptual models of flow by altering the numerical implementation of the conceptual model (dual permeability (DK) and the equivalent continuum model (ECM). Results of comparisons of the ECM and DK model are also presented in Ho et al

  12. Chemistry of groundwater and the migration process of radionuclides

    International Nuclear Information System (INIS)

    Olteanu, Mirela; Popa, Aurelia; Crina, Bucur

    2001-01-01

    Establishing the criteria of selection of a host site for final repository of low and intermediate radioactive waste is based upon the study of two major components, the radioactivity diffusion in disposal site and the environmental impact. The hydrological characteristics of geological formation are the main factors that control radionuclides moving (migration), because, in general, the water is the natural way for dissolving and transport of these in environment. In interaction of the water with environment, the water is present like a dynamic and complex system, which contents dissolved or suspension of mineral and organic substances. Knowing the water-soil system interaction mechanism, the physical-chemical characteristics of each component in this system, the mobility in time of radionuclides, from the repository in environment can be estimated. In migration, the main problem is determination of transport rate of radionuclides in environment. (authors)

  13. Innovative methods to stabilize liquid membranes for removal of radionuclides from groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Lokhandwala, K. [Membrane Technology and Research, Inc., Menlo Park, CA (United States)

    1997-10-01

    In this Phase I Small Business Innovation Research program, Membrane Technology Research, Inc., is developing a stable liquid membrane for extracting uranium and other radionuclides from groundwater. The improved membrane can also be applied to separation of other metal ions from aqueous streams in industrial operations.

  14. Experimental and modelling studies of radionuclide migration from contaminated groundwaters

    International Nuclear Information System (INIS)

    Tompkins, J. A.; Butler, A. P.; Wheater, H. S.; Shaw, G.; Wadey, P.; Bell, J. N. B.

    1994-01-01

    Lysimeter-based studies of radionuclide uptake by winter wheat are being undertaken to investigate soil-to-plant transfer processes. A five year multi-disciplinary research project has concentrated on the upward migration of contaminants from near surface water-tables and their subsequent uptake by a winter wheat crop. A weighted transfer factor approach and a physically based modelling methodology, for the simulation and prediction of radionuclide uptake, have been developed which offer alternatives to the traditional transfer factor approach. Integrated hydrological and solute transport models are used to simulate contaminant movement and subsequent root uptake. This approach enables prediction of radionuclide transport for a wide range of soil, plant and radionuclide types. This paper presents simulated results of 22 Na plant uptake and soil activity profiles, which are verified with respect to lysimeter data. The results demonstrate that a simple modelling approach can describe the variability in radioactivity in both the harvested crop and the soil profile, without recourse to a large number of empirical parameters. The proposed modelling technique should be readily applicable to a range of scales and conditions, since it embodies an understanding of the underlying physical processes of the system. This work constitutes part of an ongoing research programme being undertaken by UK Nirex Ltd., to assess the long term safety of a deep level repository for low and intermediate level nuclear waste. (author)

  15. Site scale groundwater flow in Olkiluoto

    Energy Technology Data Exchange (ETDEWEB)

    Loefman, J. [VTT Energy, Espoo (Finland)

    1999-03-01

    Groundwater flow modelling on the site scale has been an essential part of site investigation work carried out at different locations since 1986. The objective of the modelling has been to provide results that characterise the groundwater flow conditions deep in the bedrock. The main result quantities can be used for evaluation of the investigation sites and of the preconditions for safe final disposal of spent nuclear fuel. This study represents the latest modelling effort at Olkiluoto (Finland), and it comprises the transient flow analysis taking into account the effects of density variations and the repository as well as the post-glacial land uplift. The analysis is performed by means of numerical finite element simulation of coupled and transient groundwater flow and solute transport carried out up to 10000 years into the future. This work provides also the results for the site-specific data needs for the block scale groundwater flow modelling at Olkiluoto. Conceptually the fractured bedrock is divided into hydraulic units: the planar fracture zones and the remaining part of the bedrock. The equivalent-continuum (EC) model is applied so that each hydraulic unit is treated as a homogeneous and isotropic continuum with representative average characteristics. All the fracture zones are modelled explicitly and represented by two-dimensional finite elements. A site-specific simulation model for groundwater flow and solute transport is developed on the basis of the latest hydrogeological and hydrogeochemical field investigations at Olkiluoto. The present groundwater table and topography together with a mathematical model describing the land uplift at the Olkiluoto area are employed as a boundary condition at the surface of the model. The overall flow pattern is mostly controlled by the local variations in the topography. Below the island of Olkiluoto the flow direction is mostly downwards, while near the shoreline and below the sea water flows horizontally and

  16. Site scale groundwater flow in Olkiluoto

    International Nuclear Information System (INIS)

    Loefman, J.

    1999-03-01

    Groundwater flow modelling on the site scale has been an essential part of site investigation work carried out at different locations since 1986. The objective of the modelling has been to provide results that characterise the groundwater flow conditions deep in the bedrock. The main result quantities can be used for evaluation of the investigation sites and of the preconditions for safe final disposal of spent nuclear fuel. This study represents the latest modelling effort at Olkiluoto (Finland), and it comprises the transient flow analysis taking into account the effects of density variations and the repository as well as the post-glacial land uplift. The analysis is performed by means of numerical finite element simulation of coupled and transient groundwater flow and solute transport carried out up to 10000 years into the future. This work provides also the results for the site-specific data needs for the block scale groundwater flow modelling at Olkiluoto. Conceptually the fractured bedrock is divided into hydraulic units: the planar fracture zones and the remaining part of the bedrock. The equivalent-continuum (EC) model is applied so that each hydraulic unit is treated as a homogeneous and isotropic continuum with representative average characteristics. All the fracture zones are modelled explicitly and represented by two-dimensional finite elements. A site-specific simulation model for groundwater flow and solute transport is developed on the basis of the latest hydrogeological and hydrogeochemical field investigations at Olkiluoto. The present groundwater table and topography together with a mathematical model describing the land uplift at the Olkiluoto area are employed as a boundary condition at the surface of the model. The overall flow pattern is mostly controlled by the local variations in the topography. Below the island of Olkiluoto the flow direction is mostly downwards, while near the shoreline and below the sea water flows horizontally and

  17. Groundwater Flow Model of the General Separations Area Using PORFLOW

    International Nuclear Information System (INIS)

    FLACH, GREGORY

    2004-01-01

    The E Area PA (McDowell-Boyer et al. 2000) includes a steady-state simulation of groundwater flow in the General Separations Area as a prerequisite for saturated zone contaminant transport analyses. The groundwater flow simulations are based on the FACT code (Hamm and Aleman2000). The FACT-based GSA model was selected during preparation of the original PA to take advantage of an existing model developed for environmental restoration applications at the SRS (Flach and Harris 1997, 1999; Flach 1999). The existing GSA/FACT model was then slightly modified for PA use, as described in the PA document. FACT is a finite-element code utilizing deformed brick elements. Material properties are defined at element centers, and state variables such as hydraulic head are located at element vertices. The PORFLOW code (Analytic and Computational Research, Inc. 2000) was selected for performing saturated zone transport simulations of source zone radionuclides and their progeny. PORFLOW utilizes control volume discretization and the nodal point integration method, with all properties and state variables being defined at the center of an interior grid cell. The groundwater flow calculation includes translating the Darcy velocity field computed by FACT into a form compatible for input to PORFLOW. The FACT velocity field is defined at element vertices, whereas PORFLOW requires flux across cell faces. For the present PA, PORFLOW cell face flux is computed in a two-step process. An initial face flux is computed from FACT as an average of the normal components of Darcy velocity at the four corners. The derived flux field approximately conserves mass, but not rigorously. Thus, the flux field is subsequently perturbed to force rigorous mass conservation on a cell-by-cell basis. The undocumented process used is non-unique and can introduce significant artifacts into the final flux field

  18. Validation of groundwater flow model using the change of groundwater flow caused by the construction of AESPOE hard rock laboratory

    International Nuclear Information System (INIS)

    Hasegawa, Takuma; Tanaka, Yasuharu

    2004-01-01

    A numerical model based on results during pre-investigation phases was applied to the groundwater flow change caused by the construction of AEspoe HRL. The drawdowns and chloride concentration during tunnel construction were simulated to validate the numerical model. The groundwater flow was induced by inflow from the Baltic Sea to the tunnel through the hydraulic conductor domain (HCD). The time series of tunnel progress and inflow, boundaries of the Baltic Sea, transmissivity and geometry of HCD are therefore important in representing the groundwater flow. The numerical model roughly represented the groundwater flow during tunnel construction. These simulations were effective in validating the numerical model for groundwater flow and solute transport. (author)

  19. Unclassified Source Term and Radionuclide Data for the Groundwater Flow and Contaminant Transport Model of Corrective Action Units 101 and 102: Central and Western Pahute Mesa, Nye County, Nevada, Revision 0

    Energy Technology Data Exchange (ETDEWEB)

    McCord, John

    2004-08-01

    This report documents the evaluation of the information and data available on the unclassified source term and radionuclide contamination for Central and Western Pahute Mesa: Corrective Action Units (CAUs) 101 and 102.

  20. Evaluation of particle release from montmorillonite gel by flowing groundwater based on the DLVO theory

    International Nuclear Information System (INIS)

    Kurosawa, Susumu; Nagasaki, Shinya; Tanaka, Satoru

    2007-01-01

    Theoretical study has been performed to clarify the ability of colloid release form the montmorillonite gel by the flowing groundwater. Evaluation of montmorillonite colloidal particles release from the bentonite buffer material is important for the performance assessment of radioactive waste disposal because the colloids may influence the radionuclide transport. In this study, the minimum groundwater flow rate required to tear off montmorillonite particles from surface of bentonite buffer was estimated from the shear stress on the gel front, which was calculated by the DLVO theory. The estimated shear force was converted to corresponding groundwater velocity by using Stoke's equation. The results indicated that groundwater velocity in a range of about 10 -5 to 10 -4 m/s would be necessary to release montmorillonite particles. This range is higher than the groundwater flow velocity found generally in deep geological media in Japan. This study suggests that the effect of montmorillonite particles release from the bentonite buffer on radionuclide transport is likely to be negligible in the performance assessment of high-level radioactive waste geological disposal. (author)

  1. The immigration model and its implications of natural radionuclides of coastal groundwater in Xiamen

    International Nuclear Information System (INIS)

    Cai Minggang; Huang Yipu; Chen Min; Liu Guangshan

    2004-01-01

    The natural radionuclides in groundwater systems are considered to reside in three pools: dissolved, sorbed (on rock surface), and solid. Transfer of radionuclides between the dissolved and solid pools is accomplished chiefly by dissolution, (co-)precipitation and/or a-recoil. The mass balance equations model of the natural radionuclides of dissolved and adsorbed phase reservoir in groundwater is established by setting certain conditions and parameters. The modeling equations form the basic of our assessment of the effects of sorption-desorption, dissolution-precipitation, and advection-diffusion in radionuclide transport in the groundwater. The interaction between groundwater and rock in Xiamen coastal aquifers were studied quantitatively using this model, which gave us reasonable explanation for the spatial distribution of natural radium, radon isotopes activities and their activities ratio. α-recoil supply rates of 222 Rn (P r,Rn-222 ) and 224 Ra (P α,Ra-224 ) range from 0.09 x 10 3 to 3.44 x 10 3 atoms·m -3 ·s -1 and from 0.13 x l0 3 to 4.91 x 10 3 atoms·m -3 ·s -1 , respectively. P α,Ra-224 is also found to be larger than P r,Rn-222 in every station, revealing that aquifer solids contain more thorium than uranium in studied area. Both of P r,Rn-222 and P α,Ra-224 of coastal groundwater decreased seaward, revealing a-recoil supplying rates of 222 Rn and 224 Ra by aquifers rock decreased gradually, which gave good explanation of the spatial distribution characters of above two nuclides. P r,Rn-222 /A Rn-222 increase seaward from 0.3 to 0.9 along the major paths, with the average value of 0.6. Such results reveal that the primary source of groundwater 222 Rn in these areas is α-recoil of 226 Ra decay in solid pool, and its relative increase along the paths. Another source of 222 Rn is 226 Ra decay in tile sorbed pool (R f,Ra-226 ·A Ra-226 ), which attributes about 40 percent of total source of coastal groundwater 222 Rn. P α,Ra-224 /A Ra-224 ranges

  2. The immigration model and its implications of natural radionuclides of coastal groundwater in Xiamen

    International Nuclear Information System (INIS)

    Cai Minggang; Huang Yipu; Chen Min; Liu Guangshan

    2005-01-01

    The natural radionuclides in groundwater systems are considered to reside in three pools: dissolved, sorbed (on rock surface), and solid. Transfer of radionuclides between the dissolved and solid pools is accomplished chiefly by dissolution. (co-)precipitation and/or α-recoil. The mass balance equations model of the natural radionuclides of dissolved and adsorbed phase reservoir in groundwater is established by setting certain conditions and parameters. The modeling equations form the basic of our assessment of the effects of sorption-desorption, dissolution-precipitation, and advection-diffusion in radionuclide transport in the groundwater. The interaction between groundwater and rock in Xiamen coastal aquifers were studied quantitatively using this model, which gave us reasonable explanation for the spatial distribution of natural radium, radon isotopes activities and their activities ratio. α-recoil supply rates of 222 Rn (P r,Rn-22 -2) and 224 Ra (P a,Ra-224 ) range from 0.09 x l0 3 to 3.44 x 10 3 atoms·m -3 ·s -1 and from 0.13 x 10 3 to 4.91 x 10 3 x 10 3 atoms·m -3 ·s -1 , respectively. P a,Ra-224 is also found to be larger than P r,Rn-222 in every station, revealing that aquifer solids contain more thorium than uranium in studied area. Both of P r,Rn-222 and P a,Ra-224 of coastal groundwater decreased seaward, revealing α-recoil supplying rates of 222 Rn and 224 Ra by aquifers rock decreased gradually, which gave good explanation of the spatial distribution characters of above two nuclides. P r,Rn-222 /A Rn-222 increase seaward from 0.3 to 0.9 along the major paths, with the average value of 0.6, Such results reveal that the primary source of groundwater 222 Rn in these areas is α-recoil of 226 Ra decay in solid pool, and its relative increase along the paths. Another source of 222 Rn is 226 Ra decay in the sorbed pool (R f,Ra-226 ·A Ra-226 ), which attributes about 40 per cent of total source of coastal groundwater 222 Rn. P α,Ra-224 /A Ra-224

  3. Patterns in groundwater chemistry resulting from groundwater flow

    Science.gov (United States)

    Stuyfzand, Pieter J.

    Groundwater flow influences hydrochemical patterns because flow reduces mixing by diffusion, carries the chemical imprints of biological and anthropogenic changes in the recharge area, and leaches the aquifer system. Global patterns are mainly dictated by differences in the flux of meteoric water passing through the subsoil. Within individual hydrosomes (water bodies with a specific origin), the following prograde evolution lines (facies sequence) normally develop in the direction of groundwater flow: from strong to no fluctuations in water quality, from polluted to unpolluted, from acidic to basic, from oxic to anoxic-methanogenic, from no to significant base exchange, and from fresh to brackish. This is demonstrated for fresh coastal-dune groundwater in the Netherlands. In this hydrosome, the leaching of calcium carbonate as much as 15m and of adsorbed marine cations (Na+, K+, and Mg2+) as much as 2500m in the flow direction is shown to correspond with about 5000yr of flushing since the beach barrier with dunes developed. Recharge focus areas in the dunes are evidenced by groundwater displaying a lower prograde quality evolution than the surrounding dune groundwater. Artificially recharged Rhine River water in the dunes provides distinct hydrochemical patterns, which display groundwater flow, mixing, and groundwater ages. Résumé Les écoulements souterrains influencent les différents types hydrochimiques, parce que l'écoulement réduit le mélange par diffusion, porte les marques chimiques de changements biologiques et anthropiques dans la zone d'alimentation et lessive le système aquifère. Ces types dans leur ensemble sont surtout déterminés par des différences dans le flux d'eau météorique traversant le sous-sol. Dans les "hydrosomes" (masses d'eau d'origine déterminée), les lignes marquant une évolution prograde (séquence de faciès) se développent normalement dans la direction de l'écoulement souterrain : depuis des fluctuations fortes de la

  4. Regional groundwater flow in hard rocks

    Energy Technology Data Exchange (ETDEWEB)

    Pacheco, Fernando A.L., E-mail: fpacheco@utad.pt

    2015-02-15

    The territory of continental Portugal has a geologic history marked by the Hercynian orogeny, and to the north of this country the Hercynian large-scale tectonic structures are typically represented by long and deep NW–SE trending ductile shear zones and NNE–SSW trending fragile faults. These structures are elements of mineral and thermal water circuits that discharge as springs in more than one hundred locations. The purpose of this study is to investigate if these structures are also used by shallower non-mineral groundwater, integrated in a large-scale regional flow system. Using an original combination of water balance and recession flow models, it was possible to calculate catchment turnover times based solely on groundwater discharge rates and recession flow parameters. These times were then used to classify a group of 46 watersheds as closed or open basins, and among the later class to identify source and sink basins, based on innovative interpretations of relationships between turnover time and catchment area. By definition, source basins transfer groundwater to sink basins and altogether form a regional flow system. Using a Geographic Information System, it could be demonstrated the spatial association of open basins to the Hercynian ductile and fragile tectonic structures and hence to classify the basins as discharge cells of a regional flow system. Most of the studied watersheds are sub-basins of the Douro River basin, one of the largest regional catchments in the Iberian Peninsula, being located in its mouth area. Because the largest part of open basins is sink, which by definition tends to dominate in the mouth area of regional catchments, it is proposed as an extension of the studied area conceptual boundaries towards the Douro River basin headwaters, where the corresponding sources could be searched for. - Highlights: • Introduce a method to distinguish open from closed groundwater basins • Identify structural elements of a regional flow

  5. Regional groundwater flow in hard rocks

    International Nuclear Information System (INIS)

    Pacheco, Fernando A.L.

    2015-01-01

    The territory of continental Portugal has a geologic history marked by the Hercynian orogeny, and to the north of this country the Hercynian large-scale tectonic structures are typically represented by long and deep NW–SE trending ductile shear zones and NNE–SSW trending fragile faults. These structures are elements of mineral and thermal water circuits that discharge as springs in more than one hundred locations. The purpose of this study is to investigate if these structures are also used by shallower non-mineral groundwater, integrated in a large-scale regional flow system. Using an original combination of water balance and recession flow models, it was possible to calculate catchment turnover times based solely on groundwater discharge rates and recession flow parameters. These times were then used to classify a group of 46 watersheds as closed or open basins, and among the later class to identify source and sink basins, based on innovative interpretations of relationships between turnover time and catchment area. By definition, source basins transfer groundwater to sink basins and altogether form a regional flow system. Using a Geographic Information System, it could be demonstrated the spatial association of open basins to the Hercynian ductile and fragile tectonic structures and hence to classify the basins as discharge cells of a regional flow system. Most of the studied watersheds are sub-basins of the Douro River basin, one of the largest regional catchments in the Iberian Peninsula, being located in its mouth area. Because the largest part of open basins is sink, which by definition tends to dominate in the mouth area of regional catchments, it is proposed as an extension of the studied area conceptual boundaries towards the Douro River basin headwaters, where the corresponding sources could be searched for. - Highlights: • Introduce a method to distinguish open from closed groundwater basins • Identify structural elements of a regional flow

  6. Validation Analysis of the Shoal Groundwater Flow and Transport Model

    Energy Technology Data Exchange (ETDEWEB)

    A. Hassan; J. Chapman

    2008-11-01

    Environmental restoration at the Shoal underground nuclear test is following a process prescribed by a Federal Facility Agreement and Consent Order (FFACO) between the U.S. Department of Energy, the U.S. Department of Defense, and the State of Nevada. Characterization of the site included two stages of well drilling and testing in 1996 and 1999, and development and revision of numerical models of groundwater flow and radionuclide transport. Agreement on a contaminant boundary for the site and a corrective action plan was reached in 2006. Later that same year, three wells were installed for the purposes of model validation and site monitoring. The FFACO prescribes a five-year proof-of-concept period for demonstrating that the site groundwater model is capable of producing meaningful results with an acceptable level of uncertainty. The corrective action plan specifies a rigorous seven step validation process. The accepted groundwater model is evaluated using that process in light of the newly acquired data. The conceptual model of ground water flow for the Project Shoal Area considers groundwater flow through the fractured granite aquifer comprising the Sand Springs Range. Water enters the system by the infiltration of precipitation directly on the surface of the mountain range. Groundwater leaves the granite aquifer by flowing into alluvial deposits in the adjacent basins of Fourmile Flat and Fairview Valley. A groundwater divide is interpreted as coinciding with the western portion of the Sand Springs Range, west of the underground nuclear test, preventing flow from the test into Fourmile Flat. A very low conductivity shear zone east of the nuclear test roughly parallels the divide. The presence of these lateral boundaries, coupled with a regional discharge area to the northeast, is interpreted in the model as causing groundwater from the site to flow in a northeastward direction into Fairview Valley. Steady-state flow conditions are assumed given the absence of

  7. Modelling accumulation of radionuclides in terrestrial ecosystems originating from a long-term groundwater contamination

    Energy Technology Data Exchange (ETDEWEB)

    Gaerdenaes, Annemieke I. [Dept. of Soil and Environment, Swedish University of Agricultural Sciences (SLU), P.O. Box 7001, 750 07 Uppsala (Sweden); Eckersten, Henrik [Dept. of Ecology and Crop Production, SLU, P.O. Box 7042, 750 07 Uppsala (Sweden); Reinlert, Andre [Dept. of Physical Geography and Ecosystems Analysis, Lund University, 223 62 Lund (Sweden); MMT, Sven Kaellfelts Gata 11 SE 426 71 Vaestra Froelunda (Sweden); Gustafsson, David; Jansson, Per-Erik [Dept. Land and Water Resources, KTH, SE 100 44, Stockholm (Sweden); Ekstroem, Per-Anders [Facilia AB, Gustavlundsvaegen 151A, 167 51 Bromma (Sweden); Greger, Maria [Dept. of Ecology, Environment and Plant Sciences, Stockholm University, 106 91 Stockholm (Sweden)

    2014-07-01

    This study was conducted as part of the risk assessment of final deposits of nuclear fuel waste. The overall objective is to assess the possible accumulation of radionuclides in terrestrial ecosystems after an eventual long-term groundwater contamination. The specific objectives are to assess: i) What proportion of the contamination will accumulate in the soil-plant-system? ii) Where in the soil-plant- system will it accumulate? iii) Which ecosystem characteristics and radionuclides properties are important for the accumulation? and iv) Under which circumstances do losses from the ecosystems occur? We developed the dynamic model Tracey (Gaerdenaes et al. 2009) describing cycling of radionuclides in terrestrial ecosystems with high temporal resolution (1 day). The model is a multi-compartmental model in which fluxes and storage of radionuclides are described for different plant parts and soil pools in each of the 10 soil layers. The radionuclide fluxes are driven either by water or carbon fluxes. The water and the carbon fluxes are simulated with the dynamic, bio-geophysical Coup Model (Jansson and Karlberg, 2004). Tracey includes two root uptake approaches of radionuclides; (i) passive uptake driven by root water uptake and (ii) active uptake driven by plant growth. A linear approach describes the adsorption of radionuclides to soil particles and organic matter. Tracey was applied on two ecosystems with contrasting hydrology, the mixed Pinus-Picea forests found in the dry, elevated areas and the Alnus forests found in the wet, low-land areas of Uppland in central east Sweden. Different varieties of the two forest types were created by varying the root depth and radiation use efficiency. The climate was cold-temperate and based on 30-year daily weather data from Uppsala. The assumed groundwater contamination was close to 1 mg of an unspecified radionuclide per m2 and year. This load corresponds to 1 Bq per m{sup 2} and year of {sup 238}U, a common long

  8. Methods for assessing the long term radiological consequences of radionuclide entry into groundwater

    International Nuclear Information System (INIS)

    Maul, P.R.

    1983-01-01

    The methods have been developed to model the transport of radionuclides in groundwater, based on an analytical approach to the governing transport equations, are sufficiently general to enable assessments to be made of the long term radiological significance of groundwater contamination for a range of possible problems. Although the methods are not as flexible as those based on numerical solutions of the transport equations, they have several advantages, including reduced computing time. The methods described can be used to identify critical parameters and assess the significance of data uncertainties in ground-water transport calculations. Such an analysis, combined with experimental measurements where necessary, can provide a sound basis for assessing potential radiation hazards. (U.K.)

  9. Research on fracture analysis, groundwater flow and sorption processes in fractured rocks

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dae-Ha; Kim, Won-Young; Lee, Seung-Gu [Korea Institute of Geology Mining and Materials, Taejon (KR)] (and others)

    1999-12-01

    Due to increasing demand for numerous industrial facilities including nuclear power plants and waste repositories, the feasibility of rocks masses as sites for the facilities has been a geological issue of concern. Rock masses, in general, comprises systems of fractures which can provide pathways for groundwater flow and may also affect the stability of engineered structures. For the study of groundwater flow and sorption processes in fractured rocks, five boreholes were drilled. A stepwise and careful integration of various data obtained from field works and laboratory experiments were carried out to analyze groundwater flow in fractured rocks as follows; (1) investigation of geological feature of the site, (2) identification and characterization of fracture systems using core and televiewer logs, (3) determination of hydrogeological properties of fractured aquifers using geophysical borehole logging, pumping and slug tests, and continuous monitoring of groundwater level and quality, (4) evaluation of groundwater flow patterns using fluid flow modeling. The results obtained from these processes allow a qualitative interpretation of fractured aquifers in the study area. Column experiments of some reactive radionuclides were also performed to examine sorption processes of the radionuclides including retardation coefficients. In addition, analyses of fracture systems covered (1) reconstruction of the Cenozoic tectonic movements and estimation of frequency indices for the Holocene tectonic movements, (2) determination of distributions and block movements of the Quaternary marine terraces, (3) investigation of lithologic and geotechnical nature of study area, and (4) examination of the Cenozoic volcanic activities and determination of age of the dike swarms. Using data obtained from above mentioned analyses along with data related to earthquakes and active faults, probabilistic approach was performed to determine various potential hazards which may result from the

  10. Radionuclide concentrations and dose assessment of cistern water and groundwater at the Marshall Islands

    International Nuclear Information System (INIS)

    Noshkin, V.E.; Eagle, R.J.; Wong, K.M.; Jokela, T.A.; Robison, W.L.

    1981-01-01

    A radiological survey was conducted from September through November of 1978 to determine the concentrations of radionuclides in the terrestrial and marine environments of 11 atolls and 2 islands in the Northern Marshall Islands. More than 70 cistern and groundwater samples were collected at the atolls; the volume of each sample was between 55 and 100 l. The concentration of 90 Sr in cistern water at most atolls is that expected from world-wide fallout in wet deposition. Except for Bikini and Rongelap, 137 Cs concentrations in cistern water are in agreement with the average predicted concentrations from wet deposition. The 239+240 Pu concentrations are everywhere less than the predicted fallout concentrations except at Rongelap, Ailinginae, and Bikini where the measured and predicted concentrations are in general agreement. During the period sampled, most groundwater concentrations of 90 Sr and 137 Cs were everywhere higher than the concentrations in cistern water. Concentrations of the transurancies in filtered groundwater solution were everywhere comparable to or less than the concentrations in cistern water. It is concluded that the concentrations of radionuclides detected during any single period may not necessarily reflect the long-term average concentrations or the concentrations that might be observed if a lined well were extended above the surface. In any case, at all atolls the 90 Sr and 137 Cs concentrations in groundwater are below the concentration guidelines for drinking water recommended by the Environmental Protection Agency. The maximum annual dose rates and the 30- and 50-y integral doses are calculated for the intake of both cistern water and groundwater for each of the atolls

  11. Boundary delineation for regional groundwater flow through geographic information system (Contract research)

    International Nuclear Information System (INIS)

    Yamakawa, Tadashi; Munakata, Masahiro; Kimura, Hideo; Hyodo, Hiroshi

    2007-03-01

    Radionuclide migration toward the human environment is to be assessed as the part of long-term safety assessments of geologic disposal of radioactive waste. Geologic processes, which include volcanic activity, hydrothermal activity, seismicity and deformation, bring about hydrogeologic changes in the regional groundwater flow system around a repository site. Groundwater flow systems in Japan have been studied in several sites such as Tono mine, Kamaishi mine and Horonobe area, but methodology of studies in these sites does not have fully developed. This study was conducted to develop methodologies of boundary delineation for regional groundwater flow systems. Geographic Information System, GIS, was applied using available topographic, hydrologic and geologic data for an area of interest. Miyakoji in the Abukuma Mountains was selected as the area, for the reason of its simple geologic setting formed by granitic rocks and topographically gentle hills of drainage basin. Data used in this study cover topographic sheets, digital elevation model, satellite imagery, geologic maps, topographic classification maps, soil distribution maps and landuse maps. Through the GIS techniques using these data, thematic maps on topographic features, surface conditions, land coverage, geology and geologic structure and weathered crust were developed, and these thematic maps were further applied to extract four factors affecting the regional groundwater flows: topographic condition, precipitation recharge, fracture characteristics and potential flows. The present study revealed that, taking the potential groundwater flows and characteristics of fractured zones in the area into consideration, the groundwater flow system in Miyakoji drainage basin should be bounded by the Otakine Mountain and the northern part of Tokoha Drainage Basin. The delineated area is larger than understood before. (author)

  12. Groundwater flow analysis using mixed hybrid finite element method for radioactive waste disposal facilities

    International Nuclear Information System (INIS)

    Aoki, Hiroomi; Shimomura, Masanori; Kawakami, Hiroto; Suzuki, Shunichi

    2011-01-01

    In safety assessments of radioactive waste disposal facilities, ground water flow analysis are used for calculating the radionuclide transport pathway and the infiltration flow rate of groundwater into the disposal facilities. For this type of calculations, the mixed hybrid finite element method has been used and discussed about the accuracy of ones in Europe. This paper puts great emphasis on the infiltration flow rate of groundwater into the disposal facilities, and describes the accuracy of results obtained from mixed hybrid finite element method by comparing of local water mass conservation and the reliability of the element breakdown numbers among the mixed hybrid finite element method, finite volume method and nondegenerated finite element method. (author)

  13. Stochastic simulation of regional groundwater flow in Beishan area

    International Nuclear Information System (INIS)

    Dong Yanhui; Li Guomin

    2010-01-01

    Because of the hydrogeological complexity, traditional thinking of aquifer characteristics is not appropriate for groundwater system in Beishan area. Uncertainty analysis of groundwater models is needed to examine the hydrologic effects of spatial heterogeneity. In this study, fast Fourier transform spectral method (FFTS) was used to generate the random horizontal permeability parameters. Depth decay and vertical anisotropy of hydraulic conductivity were included to build random permeability models. Based on high-performance computers, hundreds of groundwater flow models were simulated. Through stochastic simulations, the effect of heterogeneity to groundwater flow pattern was analyzed. (authors)

  14. Numerical calculations on heterogeneity of groundwater flow

    International Nuclear Information System (INIS)

    Follin, S.

    1992-01-01

    The upscaling of model parameters is a key issue in many research fields concerned with parameter heterogeneity. The upscaling process allows for fewer model blocks and relaxes the numerical problems caused by high contrasts in the hydraulic conductivity. The trade-offs are dependent on the object but the general drawback is an increasing uncertainty about the representativeness. The present study deals with numerical calculations of heterogeneity of groundwater flow and solute transport in hypothetical blocks of fractured hard rock in a '3m scale' and addresses both conceptual and practical problems in numerical simulation. Evidence that the hydraulic conductivity (K) of the rock mass between major fracture zones is highly heterogeneous in a 3m scale is provided by a large number of field investigations. The present uses the documented heterogeneity and investigates flow and transport in a two-dimensional stochastic continuum characterized by a variance in Y = In(K) of σ y 2 = 16, corresponding to about 12 log 10 cycles in K. The study considers anisotropy, channelling, non-Fickian and Fickian transport, and conditional simulation. The major conclusions are: * heterogeneity gives rise to anisotropy in the upscaling process, * the choice of support scale is crucial for the modelling of solute transport. As a consequence of the obtained results, a two-dimensional stochastic discontinuum model is presented, which provides a tool for linking stochastic continuum models to discrete fracture network models. (au) (14 figs., 136 refs.)

  15. Research on fracture analysis, groundwater flow and sorption processes in fractured rocks

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dae Ha [Korea Institute of Geology Mining and Materials, Taejon (Korea)

    1998-12-01

    Due to increasing demand for numerous industrial facilities including nuclear power plants and waste repositories, the feasibility of rocks masses as sites for the facilities has been a geological issue of concern. Rock masses, in general, comprises systems of fractures which can provide pathways for groundwater flow and may also affect the stability of engineered structures. such properties of fractures stimulate a synthetic study on (1) analyses of fracture systems, and (2) characterization of groundwater flow and sorption processes in fractured rocks to establish a preliminary model for assessing suitable sites for industrial facilities. The analyses of fracture systems cover (1) reconstruction of the Cenozoic tectonic movements and estimation of frequency indices for the Holocene tectonic movements, (2) determination of distributions and block movements of the Quaternary marine terraces, (3) investigation of lithologic and geotechnical nature of study area, and (4) examination of the Cenozoic volcanic activities and determination of age of the dike swarms. Using data obtained from above mentioned analyses along with data related to earthquakes and active faults, probabilistic approach is performed to determine various potential hazards which may result from the Quaternary or the Holocene tectonic movements. In addition, stepwise and careful integration of various data obtained from field works and laboratory experiments are carried out to analyze groundwater flow in fractures rocks as follows; (1) investigation of geological feature of the site, (2) identification and characterization of fracture systems using core and televiewer logs, (3) determination of conductive fractures using electrical conductivity, temperature, and flow logs, (4) identification of hydraulic connections between fractures using televiewer logs with tracer tests within specific zones. The results obtained from these processes allow a qualitative interpretation of groundwater flow patterns

  16. Study on the flow state of groundwater by isotope tracer

    International Nuclear Information System (INIS)

    Lin Tong; Chen Jiansheng; Chen Liang

    2008-01-01

    Radioisotope logging technique is an effective method to evaluate groundwater movement. Moving with the water, the isotope tracer distributes differently in different flow states. According to the depth and time distribution of radioactivity, flow state of the groundwater can be determined. In this paper, different flow states, i.e. laminar flow, turbulent flow and mixing flow, are analyzed, and calculation of the flow velocity is discussed. Also, we discuss how to distinguish the laminar flow part and turbulent part in a mixing flow. If one judges the flow state incorrectly, the error of flow velocity will be huge, hence the importance of flow state analysis. Finally, some problems in the practical projects and measuring methods are concluded. (authors)

  17. Death Valley regional groundwater flow system, Nevada and California-Hydrogeologic framework and transient groundwater flow model

    Science.gov (United States)

    Belcher, Wayne R.; Sweetkind, Donald S.

    2010-01-01

    A numerical three-dimensional (3D) transient groundwater flow model of the Death Valley region was developed by the U.S. Geological Survey for the U.S. Department of Energy programs at the Nevada Test Site and at Yucca Mountain, Nevada. Decades of study of aspects of the groundwater flow system and previous less extensive groundwater flow models were incorporated and reevaluated together with new data to provide greater detail for the complex, digital model. A 3D digital hydrogeologic framework model (HFM) was developed from digital elevation models, geologic maps, borehole information, geologic and hydrogeologic cross sections, and other 3D models to represent the geometry of the hydrogeologic units (HGUs). Structural features, such as faults and fractures, that affect groundwater flow also were added. The HFM represents Precambrian and Paleozoic crystalline and sedimentary rocks, Mesozoic sedimentary rocks, Mesozoic to Cenozoic intrusive rocks, Cenozoic volcanic tuffs and lavas, and late Cenozoic sedimentary deposits of the Death Valley regional groundwater flow system (DVRFS) region in 27 HGUs. Information from a series of investigations was compiled to conceptualize and quantify hydrologic components of the groundwater flow system within the DVRFS model domain and to provide hydraulic-property and head-observation data used in the calibration of the transient-flow model. These studies reevaluated natural groundwater discharge occurring through evapotranspiration (ET) and spring flow; the history of groundwater pumping from 1913 through 1998; groundwater recharge simulated as net infiltration; model boundary inflows and outflows based on regional hydraulic gradients and water budgets of surrounding areas; hydraulic conductivity and its relation to depth; and water levels appropriate for regional simulation of prepumped and pumped conditions within the DVRFS model domain. Simulation results appropriate for the regional extent and scale of the model were provided

  18. Interpreting Repeated Temperature-Depth Profiles for Groundwater Flow

    NARCIS (Netherlands)

    Bense, Victor F.; Kurylyk, Barret L.; Daal, van Jonathan; Ploeg, van der Martine J.; Carey, Sean K.

    2017-01-01

    Temperature can be used to trace groundwater flows due to thermal disturbances of subsurface advection. Prior hydrogeological studies that have used temperature-depth profiles to estimate vertical groundwater fluxes have either ignored the influence of climate change by employing steady-state

  19. General Separations Area (GSA) Groundwater Flow Model Update: Hydrostratigraphic Data

    Energy Technology Data Exchange (ETDEWEB)

    Bagwell, L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Bennett, P. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Flach, G. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-02-21

    This document describes the assembly, selection, and interpretation of hydrostratigraphic data for input to an updated groundwater flow model for the General Separations Area (GSA; Figure 1) at the Department of Energy’s (DOE) Savannah River Site (SRS). This report is one of several discrete but interrelated tasks that support development of an updated groundwater model (Bagwell and Flach, 2016).

  20. Comparing groundwater recharge and base flow in the Bukmoongol ...

    Indian Academy of Sciences (India)

    model, also known as the Rorabaugh Method. (Rorabaugh 1960; Daniel 1976; Rutledge 2007b), estimates groundwater recharges for each stream- flow peak using the recession-curve-displacement method. It is based on an analytical model that describes groundwater discharge subsequent to recharge to the water table ...

  1. Death Valley regional ground-water flow system, Nevada and California -- hydrogeologic framework and transient ground-water flow model

    Science.gov (United States)

    Belcher, Wayne R.

    2004-01-01

    A numerical three-dimensional (3D) transient ground-water flow model of the Death Valley region was developed by the U.S. Geological Survey for the U.S. Department of Energy programs at the Nevada Test Site and at Yucca Mountain, Nevada. Decades of study of aspects of the ground-water flow system and previous less extensive ground-water flow models were incorporated and reevaluated together with new data to provide greater detail for the complex, digital model. A 3D digital hydrogeologic framework model (HFM) was developed from digital elevation models, geologic maps, borehole information, geologic and hydrogeologic cross sections, and other 3D models to represent the geometry of the hydrogeologic units (HGUs). Structural features, such as faults and fractures, that affect ground-water flow also were added. The HFM represents Precambrian and Paleozoic crystalline and sedimentary rocks, Mesozoic sedimentary rocks, Mesozoic to Cenozoic intrusive rocks, Cenozoic volcanic tuffs and lavas, and late Cenozoic sedimentary deposits of the Death Valley Regional Ground-Water Flow System (DVRFS) region in 27 HGUs. Information from a series of investigations was compiled to conceptualize and quantify hydrologic components of the ground-water flow system within the DVRFS model domain and to provide hydraulic-property and head-observation data used in the calibration of the transient-flow model. These studies reevaluated natural ground-water discharge occurring through evapotranspiration and spring flow; the history of ground-water pumping from 1913 through 1998; ground-water recharge simulated as net infiltration; model boundary inflows and outflows based on regional hydraulic gradients and water budgets of surrounding areas; hydraulic conductivity and its relation to depth; and water levels appropriate for regional simulation of prepumped and pumped conditions within the DVRFS model domain. Simulation results appropriate for the regional extent and scale of the model were

  2. Treatment of heavy metals and radionuclides in groundwater and wastewater by magnetic separation

    International Nuclear Information System (INIS)

    Bradbury, D.; Elder, G.R.; Tucker, P.M.; Dunn, M.J.

    1992-01-01

    Removal of trace quantities of heavy metal or radionuclide contamination from solutions at high flow rate presents a considerable technical challenge. Low flow methods of treatment such as particle gravity settling require expensive large volume equipment, whereas traditional methods of filtration demand significant energy costs. Magnetic filtration can be used to provide a low cost method of solid-liquid separation at high flow rate, provided contaminants can be selectively bound to a magnetic solid particle. This paper describes recent progress with this technique including performance tests of composite materials produced to selectively remove specific contaminants such as cesium, uranium, lead, cadmium, and mercury from solution

  3. Characterizing Groundwater Level and Flow Pattern in a Shallow ...

    African Journals Online (AJOL)

    Bheema

    This study characterize groundwater yield and flow pattern on a shallow ... simple process of weathering, fractured fissure systems, networks of joints and ..... lowest yield in wells that are deeper than the mean well depth in the study area.

  4. Estimation of groundwater residence time and evaluation of geomorphological processes using cosmogenic and terrigenic radionuclides and isotopes of noble gases

    International Nuclear Information System (INIS)

    Mahara, Yasunori; Ohta, Tomoko; Igarashi, Toshifumi

    2013-01-01

    In this paper, the estimation of groundwater residence time and geomorphological changing processes are discussed by focusing on isotopes of noble gases and radionuclides with a long half-life as an environmental tracer. Noble gases and radionuclides are produced in the atmospheric air and terrestrial rocks by spallation and various muon reactions during cosmic rays irradiation. Groundwater dating and geomorphological changing are estimated from changes in the number of atoms of cosmogenic and terrigenic nuclides in groundwater and terrestrial rock. The main tools of groundwater dating are combination of the dissolved helium and tritium (half-life T 1/2 =12.3 y) for younger groundwater less than 60 years of residence time, and of the dissolved helium and 36 Cl (T 1/2 =3.01 x 10 5 y) for older groundwater over million years. On the other hand, the main tools on the geomorphological changes are the estimation of exposure time using cosmogenic radionuclides ( 10 Be(half-life T 1/2 =1.6 x 10 6 y), 14 C (T 1/2 =5730 y), 26 Al (T 1/2 =7.16 x 10 5 y) and 36 Cl) and cosmogenic stable noble gases ( 3 He and 21 Ne) produced in rock. (author)

  5. Simulation of Groundwater Flow, Denpasar-Tabanan Groundwater Basin, Bali Province

    Directory of Open Access Journals (Sweden)

    Heryadi Tirtomihardjo

    2014-06-01

    Full Text Available DOI: 10.17014/ijog.v6i3.123Due to the complex structure of the aquifer systems and its hydrogeological units related with the space in which groundwater occurs, groundwater flows were calculated in three-dimensional method (3D Calculation. The geometrical descritization and iteration procedures were based on an integrated finite difference method. In this paper, all figures and graphs represent the results of the calibrated model. Hence, the model results were simulated by using the actual input data which were calibrated during the simulation runs. Groundwater flow simulation of the model area of the Denpasar-Tabanan Groundwater Basin (Denpasar-Tabanan GB comprises steady state run, transient runs using groundwater abstraction in the period of 1989 (Qabs-1989 and period of 2009 (Qabs-2009, and prognosis run as well. Simulation results show, in general, the differences of calculated groundwater heads and observed groundwater heads at steady and transient states (Qabs-1989 and Qabs-2009 are relatively small. So, the groundwater heads situation simulated by the prognosis run (scenario Qabs-2012 are considerably valid and can properly be used for controlling the plan of groundwater utilization in Denpasar-Tabanan GB.

  6. Pulmonary blood flow distribution measured by radionuclide computed tomography

    International Nuclear Information System (INIS)

    Maeda, H.; Itoh, H.; Ishii, Y.

    1982-01-01

    Distributions of pulmonary blood flow per unit lung volume were measured in sitting patients with a radionuclide computed tomography (RCT) by intravenously administered Tc-99m macroaggregates of human serum albumin (MAA). Four different types of distribution were distinguished, among which a group referred as type 2 had a three zonal blood flow distribution as previously reported (West and co-workers, 1964). The pulmonary arterial pressure (Pa) and the venous pressure (Pv) were determined in this group of distribution. These values showed satifactory agreements with the pulmonary artery pressure (Par) and the capillary wedged pressure (Pcw) measured by Swan-Ganz catheter in eighteen supine patients. Those good correlations enable to establish a noninvasive methodology for measurement of pulmonary vascular pressures

  7. Simulation of the groundwater flow of the Kivetty area

    International Nuclear Information System (INIS)

    Taivassalo, V.; Meszaros, F.

    1994-02-01

    Teollisuuden Voima Oy (TVO) is preparing for the final disposal of spent nuclear fuel into crystalline bedrock in Finland. Groundwater flow modelling is a part of the preliminary site investigation work. The aim is to simulate groundwater flow as realistically as possible in view of the experimental data available. Three dimensional groundwater flow modelling is based on a conceptual bedrock model. The modelling results will be used in the site evaluation process. Observations from flow simulations will also be used to identify and study uncertainties included in the site characterization. First a conceptual flow model for the Kivetty site in Konginkangas was developed. As a second stage the flow model was calibrated. The goal was to increase the reality of the model. To evaluate the reality of the flow model, the values of the input and output parameters were compared with the field data. Finally groundwater flow simulation results were computed and groundwater flow at the Kivetty area was analysed. (50 refs., 78 figs., 7 tabs.)

  8. Radionuclide study on hepatic blood flow in Schistosomiasis Japonica

    Energy Technology Data Exchange (ETDEWEB)

    Okada, Junichi; Uchiyama, Guio; Hayakawa, Kazushige; Hayashi, Sanshin; Araki, Tsutomu; Arai, Takao; Iuchi, Masahiko

    1986-11-01

    Schistosomiasis Japonica is a regional disease found in elderly people who were living in once-endemic areas in Japan. Yamanashi was one of these areas until 1970, since when no newly infected patients were reported. The disease is characteristic of developing irreversible interstitial fibrosis of the liver, where parasites migrate and lay eggs. Portal hypertension, esophageal varices and hepatocellular carcinomas are the common features of the results. In order to estimate patient's hepatic blood flow, radionuclide angiography of the liver with the use of 10 - 15 millicuries of Tc-99m phytate were performed prior to the conventional multiview imaging. Twenty-two patients with schistosomiasis and twelve adults without evidence of liver disease were studied. A time-activity curve of the right lobe of the liver was generated by a computer, and the ratio of arterial blood flow to portal blood flow was calculated. As a result, a good correlation was found between the arterial to portal blood flow ratio and the grade of hepatic fibrosis verified by laparoscopic biopsy. The development of esophageal varices were likely to correlate well with the blood flow ratio rather than scores on the conventional static liver and spleen scintigram. The study was useful for evaluating patient's clinical stages and prognosis.

  9. Radionuclide study on hepatic blood flow in Schistosomiasis Japonica

    International Nuclear Information System (INIS)

    Okada, Junichi; Uchiyama, Guio; Hayakawa, Kazushige; Hayashi, Sanshin; Araki, Tsutomu; Arai, Takao; Iuchi, Masahiko.

    1986-01-01

    Schistosomiasis Japonica is a regional disease found in elderly people who were living in once-endemic areas in Japan. Yamanashi was one of these areas until 1970, since when no newly infected patients were reported. The disease is characteristic of developing irreversible interstitial fibrosis of the liver, where parasites migrate and lay eggs. Portal hypertension, esophageal varices and hepatocellular carcinomas are the common features of the results. In order to estimate patient's hepatic blood flow, radionuclide angiography of the liver with the use of 10 - 15 millicuries of Tc-99m phytate were performed prior to the conventional multiview imaging. Twenty-two patients with schistosomiasis and twelve adults without evidence of liver disease were studied. A time-activity curve of the right lobe of the liver was generated by a computer, and the ratio of arterial blood flow to portal blood flow was calculated. As a result, a good correlation was found between the arterial to portal blood flow ratio and the grade of hepatic fibrosis verified by laparoscopic biopsy. The development of esophageal varices were likely to correlate well with the blood flow ratio rather than scores on the conventional static liver and spleen scintigram. The study was useful for evaluating patient's clinical stages and prognosis. (author)

  10. 238U-series radionuclides in Finnish groundwater-based drinking water and effective doses

    International Nuclear Information System (INIS)

    Vesterbacka, P.

    2005-09-01

    The thesis deals with the occurrence of 238 U-series radionuclides and particle-bound 210 Pb and 210 Po in Finnish groundwater-based drinking water, methods used for removing 234 U, 238 U, 210 Pb and 210 Po, and the annual effective doses caused by 238 U-series radionuclides in drinking water. In order to reduce radiation exposure and avoid high doses, it is important to examine the activity levels of natural radionuclides in groundwater. In this work, the activity concentrations of radon ( 222 Rn), radium ( 226 Ra), uranium ( 238 U and 234 U), lead ( 210 Pb) and polonium ( 210 Po) were determined from 472 private wells, which were selected randomly from across Finland. On the basis of the results, the activity concentrations in groundwater and the radiation exposure from drinking water of people living outside the public water supply in Finland was specified. The efficiency of 238 U, 234 U, 210 Pb and 210 Po removal from drinking water was examined at ten private homes. In order to obtain accurate results and correct estimates of effective doses, attention was paid to the sampling of 222 Rn and 210 Pb, and the determination of 210 Pb. The results revealed that the median activity concentrations of natural radionuclides were as much as ten times higher in drilled wells than in wells dug in soil. The average activity concentration of 222 Rn in drilled wells was 460 Bq/l and in dug wells 50 Bq/l. The highest activity concentrations were found in Southern Finland. In addition, occasional high activity concentrations were found all over Finland. The average activity concentrations of 234 U and 238 U in drilled wells were 0.35 and 0.26 Bq/l and in dug wells 0.020 and 0.015 Bq/l, respectively. The spatial distribution of 234 U, 238 U, 210 Pb and 210 Po was essentially similar to that of 222 Rn. In contrast to other natural radionuclides, the highest 226 Ra activity concentrations were found in coastal areas, since drilled well water near the sea has a higher salinity

  11. Characterization of groundwater flow for near surface disposal facilities

    International Nuclear Information System (INIS)

    2001-02-01

    The main objective of this report is to provide a description of the site investigation techniques and modelling approaches that can be used to characterise the flow of subsurface water at near surface disposal facilities in relation to the various development stages of the repositories. As one of the main goals of defining groundwater flow is to establish the possible contaminant migration, certain aspects related to groundwater transport are also described. Secondary objectives are to discuss the implications of various groundwater conditions with regard to the performance of the isolation systems

  12. Research on flow characteristics of deep groundwater by environmental isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Shimada, Jun; Miyaoka, Kunihide [Tsukuba Univ., Ibaraki (Japan); Sakurai, Hideyuki; Senoo, Muneaki; Kumata, Masahiro; Mukai, Masayuki; Watanabe, Kazuo; Ouchi, Misao

    1996-01-01

    In this research, as the technique for grasping the behavior of groundwater in deep rock bed which is important as the factor of disturbing the natural barrier in the formation disposal of high level radioactive waste, the method of utilizing the environmental isotopes contained in groundwater as natural tracer was taken up, and by setting up the concrete field of investigation, through the forecast of flow by the two or three dimensional groundwater flow analysis using a computer, the planning and execution of water sampling, the analysis of various environmental isotopes, the interpretation based on those results of measurement and so on, the effectiveness of the investigation technique used was verified, and the real state of the behavior of deep groundwater in the district being studied was clarified. In this research, Imaichi alluvial fan located in northern Kanto plain was taken as the object. In fiscal year 1996, three-dimensional steady state groundwater flow simulation was carried out based on the data related to shallow groundwater and surface water systems, and the places where active groundwater flow is expected were selected, and boring will be carried out there. The analysis model and the results are reported. (K.I.)

  13. Colloid and radionuclide retention mechanisms in fractured rock under near-natural flow conditions

    International Nuclear Information System (INIS)

    Delos, A.; Schaefer, T.; Geckeis, H.; Guimera, J.; Carrera, J.; Fanghaenel, T.

    2005-01-01

    Full text of publication follows: Experiments in fractured host rock (Grimsel Test Site, GTS, Switzerland) revealed that the colloid relevance for actinide migration is high due to the specific geochemical groundwater conditions [1]. However, even under such conditions it is found that retention of colloids and colloid-borne actinides becomes significant under near-natural groundwater flow rates (1-10 m/a) [2]. Underlying mechanisms of colloid and radionuclide retention are not well understood up to now. The present study co-funded by the NoE ACTINET-6 focuses on (i) the kinetics of actinide-colloid interactions and (ii) the relevance of matrix diffusion as a competition process to other retention mechanisms which affect the actinides behavior in fractured rock systems such as the Grimsel granodiorite. Colloid migration is studied with well defined model colloids as e.g. fluorescence dyed carboxylated polystyrene particles, and natural colloids extracted from bentonite (FEBEX) and from fracture filling material (GTS). In order to study the influence of matrix porosity on actinides migration, those experiments are performed in columns of well defined geometry filled with microporous unmodified silica spheres, porous ceramic material and natural fracture filling material from the GTS. The behaviour of actinides (Pu(IV) and Am(III)) sorbed onto bentonite colloids is investigated in column and batch experiments. All experiments are performed under anoxic conditions. Colloid characterization methods used in this study include the combination of photon correlation spectroscopy (PCS), laser-induced breakdown detection (LIBD), fluorimetry and field flow fractionation (FFF). Experimental results and their application to the parametrisation of reactive colloid transport models are discussed. [1] Geckeis H, Schaefer T, Hauser W, Rabung T, Missana T, Degueldre C, Moeri A, Eikenberg J, Fierz T, Alexander WR (2004) Results of the Colloid and Radionuclide Retention experiment

  14. Concepts of Groundwater Occurrence and Flow Near Oak Ridge National Laboratory, Tennessee

    International Nuclear Information System (INIS)

    Moore, G.K.

    1988-01-01

    . At deeper levels all effective porosity is in fractures. The subsurface hydrology of the ORNL area is also more favorable for the containment of radioactive wastes than has been indicated by previous reports. A relatively simple solution should be possible for the problem of radionuclide migration in groundwater. The key concepts for most remedial investigations may be hydrologic isolation of contaminated materials by stopping infiltration and lateral flows in the stormflow zone

  15. Screening Assessment of Radionuclide Migration in Groundwater from the “Dneprovskoe” Tailings Impoundment (Dneprodzerzhynsk City) and Evaluation of Remedial Options

    Energy Technology Data Exchange (ETDEWEB)

    Skalskyi, O.; Bugai, D. [Institute of Geological Sciences, National Academy of Sciences of Ukraine (Ukraine); Ryazantsev, V. [State Nuclear Regularity Committee of Ukraine, Kiev (Ukraine)

    2014-05-15

    The paper presents results of mathematical modeling of the hydrogeological conditions at the “Dneprovskoe” (“D”) tailings impoundment –object of the former industrial association of “Pridneprovsky Chemical Plant”, which contains uranium ore processing wastes. This radioactively polluted site is located in a densely populated region (at the outskirts of Dneprodzerginsk City) near the major watercourse of the Ukraine — Dnieper River.The mathematical modeling utilized Visual Modflow (for groundwater flow) and Ecolego (Facilia AB, Sweden) radioecology modeling software (for radionuclide transport).Modeling results indicate the possibility of essential radioactive contamination in future of the phreatic aquifer in alluvial deposits between the “D” tailings and the Dnieper River (mainly due to migration of uranium). Therefore long-term management strategies should preclude water usage from the aquifer in the zone of the in-fluence of the “D” tailings. Filtration discharge of uranium to the Dnepr River does not represent a significant risk due to large dilution by surface waters. The important modeling conclusion is that besides the uranium ore processing wastes inside the tailings, the major source of radionuclide migration to groundwater is represented by contaminated geological deposits below the tailings. This last source was formed due to leakage of wastewaters during the operational period of the “D” tailings (1954–1968). Therefore an exemption and re-disposal of wastes from the “D” tailings to a more safe storage location (proposed by some remedial plans) will not provide significant benefit from the viewpoint of minimizing of radionuclide transport to the groundwater and Dnieper River (especially in short-and medium-term perspective). The rational remedial strategy for the “D” tailings is conservation of tailing wastes in-situ by means of specially designed “zero flux” soil screen, which would minimize infiltration of

  16. Investigation of radionuclides and anthropic tracer migration in groundwater at the Chernobyl site

    Science.gov (United States)

    Le Gal La Salle, Corinnne; Simonucci, Caroline; Roux, Céline; Bugai, Dmitry; Aquilina, Luc; Fourré, Elise; Jean-Baptiste, Philippe; Labasque, Thierry; Michelot, Jean-Luc; Fifield, Keith; Team Aster Team; Van Meir, Nathalie; Kashparov, Valeriy; Diez, Olivier; Bassot, Sylvain; Lancelot, Joel

    2013-04-01

    Following the reactor 4 explosion of the Chernobyl Nuclear Power Plant (ChNPP), at least 1019 Bq of radionuclides (RN) were released in the environment. In order to protect workers and prevent further atmospheric RN dispersion in the area adjacent to the ChNPP, contaminated wastes including fuel particles, topsoil layer and forest remains were buried in approximately 800 shallow trenches in the sand formation in the Red Forest waste dump site [1]. No containment measures were taken, and since then RN have leaked to the unsaturated zone and to the groundwater. Since 1999, migration of RN in the vicinity of the trench 22 at Red Forest site has been investigated within the frame of the EPIC program carried out by IRSN in collaboration with UIAR and IGS [2, 3]. A plume of 90Sr was shown downgradient from the trench 22 with activites reaching 3750 Bq/L [2]. In 2008, further studies were initiated through the TRASSE research group, based on a collaboration between IRSN and CNRS. These programs aim at combining groundwater dating with RN migration monitoring studies in order to constrain RN transport models [3]. Groundwater residence time was investigated based on 3H/He and CFC. Both tracers led to ages ranging from modern (1-3 y) at 2 m depth below the groundwater table to significantly higher apparent ages of 50-60 y at 27 m below the groundwater table [3]. 36Cl/Cl ratios 2 to 4 orders of magnitude higher than the theoretical natural ratio are measured in groundwater. Similarly, SF6 shows concentrations as high as 1200 pptv while natural concentrations are in the order of 6-7 pptv. Based on apparent groundwater ages, both contaminations are linked to the Chernobyl explosion. Hence those tracers show excellent potential to constrain conservative and reactive transport, respectively. In contrast, 238U/235U ratio down gradient from trench 22 remains similar to the natural ratio. This suggests that either most of the U contained in the trench is in a non soluble form

  17. Assessing the velocity of the groundwater flow in bedrock fractures

    International Nuclear Information System (INIS)

    Taivassalo, V.; Poteri, A.

    1994-10-01

    Teollisuuden Voima Oy (TVO) is studying the crystalline bedrock in Finland for the final disposal of the spent nuclear fuel from its two reactors in Olkiluoto. Preliminary site investigations for five areas were carried out during 1987-1992. One part of the investigation programme was three-dimensional groundwater flow modelling. The numerical site-specific flow simulations were based on the concept of an equivalent porous continuum. The results include hydraulic head distributions, average groundwater flow rate routes. In this study, a novel approach was developed to evaluate the velocities of the water particles flowing in the fractured bedrock. (17 refs., 15 figs., 5 tabs.)

  18. Groundwater flow modelling under ice sheet conditions. Scoping calculations

    Energy Technology Data Exchange (ETDEWEB)

    Jaquet, O.; Namar, R. (In2Earth Modelling Ltd (Switzerland)); Jansson, P. (Dept. of Physical Geography and Quaternary Geology, Stockholm Univ., Stockholm (Sweden))

    2010-10-15

    The potential impact of long-term climate changes has to be evaluated with respect to repository performance and safety. In particular, glacial periods of advancing and retreating ice sheet and prolonged permafrost conditions are likely to occur over the repository site. The growth and decay of ice sheets and the associated distribution of permafrost will affect the groundwater flow field and its composition. As large changes may take place, the understanding of groundwater flow patterns in connection to glaciations is an important issue for the geological disposal at long term. During a glacial period, the performance of the repository could be weakened by some of the following conditions and associated processes: - Maximum pressure at repository depth (canister failure). - Maximum permafrost depth (canister failure, buffer function). - Concentration of groundwater oxygen (canister corrosion). - Groundwater salinity (buffer stability). - Glacially induced earthquakes (canister failure). Therefore, the GAP project aims at understanding key hydrogeological issues as well as answering specific questions: - Regional groundwater flow system under ice sheet conditions. - Flow and infiltration conditions at the ice sheet bed. - Penetration depth of glacial meltwater into the bedrock. - Water chemical composition at repository depth in presence of glacial effects. - Role of the taliks, located in front of the ice sheet, likely to act as potential discharge zones of deep groundwater flow. - Influence of permafrost distribution on the groundwater flow system in relation to build-up and thawing periods. - Consequences of glacially induced earthquakes on the groundwater flow system. Some answers will be provided by the field data and investigations; the integration of the information and the dynamic characterisation of the key processes will be obtained using numerical modelling. Since most of the data are not yet available, some scoping calculations are performed using the

  19. Groundwater flow modelling under ice sheet conditions. Scoping calculations

    International Nuclear Information System (INIS)

    Jaquet, O.; Namar, R.; Jansson, P.

    2010-10-01

    The potential impact of long-term climate changes has to be evaluated with respect to repository performance and safety. In particular, glacial periods of advancing and retreating ice sheet and prolonged permafrost conditions are likely to occur over the repository site. The growth and decay of ice sheets and the associated distribution of permafrost will affect the groundwater flow field and its composition. As large changes may take place, the understanding of groundwater flow patterns in connection to glaciations is an important issue for the geological disposal at long term. During a glacial period, the performance of the repository could be weakened by some of the following conditions and associated processes: - Maximum pressure at repository depth (canister failure). - Maximum permafrost depth (canister failure, buffer function). - Concentration of groundwater oxygen (canister corrosion). - Groundwater salinity (buffer stability). - Glacially induced earthquakes (canister failure). Therefore, the GAP project aims at understanding key hydrogeological issues as well as answering specific questions: - Regional groundwater flow system under ice sheet conditions. - Flow and infiltration conditions at the ice sheet bed. - Penetration depth of glacial meltwater into the bedrock. - Water chemical composition at repository depth in presence of glacial effects. - Role of the taliks, located in front of the ice sheet, likely to act as potential discharge zones of deep groundwater flow. - Influence of permafrost distribution on the groundwater flow system in relation to build-up and thawing periods. - Consequences of glacially induced earthquakes on the groundwater flow system. Some answers will be provided by the field data and investigations; the integration of the information and the dynamic characterisation of the key processes will be obtained using numerical modelling. Since most of the data are not yet available, some scoping calculations are performed using the

  20. Groundwater flow and heterogeneous discharge into a seepage lake

    DEFF Research Database (Denmark)

    Kazmierczak, Jolanta; Müller, Sascha; Nilsson, B.

    2016-01-01

    with the lake remained under seemingly steady state conditions across seasons, a high spatial and temporal heterogeneity in the discharge to the lake was observed. The results showed that part of the groundwater flowing from the west passes beneath the lake and discharges at the eastern shore, where groundwater......Groundwater discharge into a seepage lake was investigated by combining flux measurements, hydrochemical tracers, geological information, and a telescopic modeling approach using first two-dimensional (2-D) regional then 2-D local flow and flow path models. Discharge measurements and hydrochemical...... tracers supplement each other. Discharge measurements yield flux estimates but rarely provide information about the origin and flow path of the water. Hydrochemical tracers may reveal the origin and flow path of the water but rarely provide any information about the flux. While aquifer interacting...

  1. Modeling of groundwater flow for Mujib aquifer, Jordan

    Indian Academy of Sciences (India)

    Jordan is an arid country with very limited water resources. ... groundwater flow model to simulate the behavior of the flow system under ... decision makers and planners in selecting optimum management schemes suitable for arid and semi- arid regions. 2. Methodology ..... This work was supported by the Jordan University.

  2. A generalised groundwater flow equation using the concept of non ...

    African Journals Online (AJOL)

    The classical Darcy law is generalised by regarding the water flow as a function of a non-integer order derivative of the piezometric head. This generalised law and the law of conservation of mass are then used to derive a new equation for groundwater flow. Numerical solutions of this equation for various fractional orders of ...

  3. Evaluation and testing of HUMASORB-CS trademark for the removal of radionuclides from groundwater

    International Nuclear Information System (INIS)

    Mann, N.R.; Todd, T.A.; Wood, D.J.

    1998-01-01

    An independent experiment to demonstrate the combined removal of the radionuclides, 85 Sr and 137 Cs from groundwater has been conducted with the sorbent, HUMASORB-CS. Arctech, Inc. manufactures this humic acid-based sorbent material. This sorbent material is reported to have potential for remediation of contaminated groundwater present at DOE sites. The purpose of this work was to evaluate the removal efficiency and the capacity of the sorbent. Two ion-exchange columns were assembled at the Idaho Chemical Processing Plant (ICPP) to evaluate the sorbent technology. Initial 137 Cs breakthrough in both columns was observed after 22.0 and 30.2 bed volumes, respectively. Strontium-85 removal was slightly more efficient than 137 Cs removal. Initial 85 Sr breakthrough in both columns was observed after 29.4 and 22.7 bed volumes, respectively. Calcium, which is of concern, is the major constituent within the feed solution. Calcium is attributed to loading interference in addition to other alkaline and alkaline earth metals such as stable Sr, Mg, Na, K, and Ba. Interfering ions fill exchange sites that greatly reduce the sorbents efficiency to sorb targeted ions such as radioactive Cs and Sr. Despite high concentrations of Ca in the feed solution, Ca was not sorbed by HUMASORB-CS. Results indicate HUMASORB-CS does not sorb sodium or potassium. Sodium and potassium concentrations were consistently observed at 100% breakthrough throughout the test

  4. Colloid migration in groundwaters: Geochemical interactions of radionuclides with natural colloids. Appendix III

    International Nuclear Information System (INIS)

    Wolf, M.; Geyer, S.; Fritz, P.; Klotz, D.; Lazik, D.

    1994-01-01

    The results obtained from the 152 Eu migration experiment in various columns packed with fine grained sand and equilibrated with a humic substance rich groundwater are: The retardation of mobile Eu-pseudocolloids (Eu-humate) is negligible, since the recovery is 152 Eu concentration is irreversible sorbed on the column, the degree of filtration expressed by the recovery is strongly dependant on the filtration velocity (flow rate): The recovery increases with increasing flow rates, indicating decreasing filtration, since the humic substances are negatively charged, the migration of the Eu pseudocolloids (humic colloids) is slightly accelerated relative to the migration of the 3 HHO tracer, due to anion repulsion. (orig.)

  5. Climate reconstruction from borehole temperatures influenced by groundwater flow

    Science.gov (United States)

    Kurylyk, B.; Irvine, D. J.; Tang, W.; Carey, S. K.; Ferguson, G. A. G.; Beltrami, H.; Bense, V.; McKenzie, J. M.; Taniguchi, M.

    2017-12-01

    Borehole climatology offers advantages over other climate reconstruction methods because further calibration steps are not required and heat is a ubiquitous subsurface property that can be measured from terrestrial boreholes. The basic theory underlying borehole climatology is that past surface air temperature signals are reflected in the ground surface temperature history and archived in subsurface temperature-depth profiles. High frequency surface temperature signals are attenuated in the shallow subsurface, whereas low frequency signals can be propagated to great depths. A limitation of analytical techniques to reconstruct climate signals from temperature profiles is that they generally require that heat flow be limited to conduction. Advection due to groundwater flow can thermally `contaminate' boreholes and result in temperature profiles being rejected for regional climate reconstructions. Although groundwater flow and climate change can result in contrasting or superimposed thermal disturbances, groundwater flow will not typically remove climate change signals in a subsurface thermal profile. Thus, climate reconstruction is still possible in the presence of groundwater flow if heat advection is accommodated in the conceptual and mathematical models. In this study, we derive a new analytical solution for reconstructing surface temperature history from borehole thermal profiles influenced by vertical groundwater flow. The boundary condition for the solution is composed of any number of sequential `ramps', i.e. periods with linear warming or cooling rates, during the instrumented and pre-observational periods. The boundary condition generation and analytical temperature modeling is conducted in a simple computer program. The method is applied to reconstruct climate in Winnipeg, Canada and Tokyo, Japan using temperature profiles recorded in hydrogeologically active environments. The results demonstrate that thermal disturbances due to groundwater flow and climate

  6. A Guide for Using the Transient Ground-Water Flow Model of the Death Valley Regional Ground-Water Flow System, Nevada and California

    Energy Technology Data Exchange (ETDEWEB)

    Joan B. Blainey; Claudia C. Faunt, and Mary C. Hill

    2006-05-16

    This report is a guide for executing numerical simulations with the transient ground-water flow model of the Death Valley regional ground-water flow system, Nevada and California using the U.S. Geological Survey modular finite-difference ground-water flow model, MODFLOW-2000. Model inputs, including observations of hydraulic head, discharge, and boundary flows, are summarized. Modification of the DVRFS transient ground-water model is discussed for two common uses of the Death Valley regional ground-water flow system model: predictive pumping scenarios that extend beyond the end of the model simulation period (1998), and model simulations with only steady-state conditions.

  7. An initial examination of tungsten geochemistry along groundwater flow paths

    Science.gov (United States)

    Dave, H. B.; Johannesson, K. H.

    2008-12-01

    Groundwater samples were collected along groundwater flow paths from the Upper Floridan (Florida), Carrizo Sand (Texas), and the Aquia (Maryland) aquifers and analyzed for tungsten (W) concentrations by high- resolution inductively couple plasma mass spectrometry. At each well head, groundwater samples were also analyzed for pH, specific conductance, temperature, alkalinity, dissolved oxygen (DO), oxidation-reduction potential (Eh), dissolved iron speciation, and dissolved sulfide [S(-II)] concentrations. Sediment samples from the Carrizo Sand and Aquia aquifers were also collected and subjected to sequential extractions to provide additional insights into the solid-phase speciation of W in these aquifers. Tungsten concentrations varied along the groundwater flow paths chiefly in response to changing pH, and to a lesser extent, variations in the redox conditions. For groundwater from the Carrizo Sand aquifer, W ranges between 3.64 and 1297 pmol/kg, exhibiting the lowest values proximal to the recharge zone. Tungsten concentrations progressively increase along the flow path, reaching 1297 pmol/kg in the sulfidic groundwaters located approximately 60 km downgradient from the recharge area. Tungsten is strongly correlated with S(-II) concentrations and pH in Carrizo groundwaters (r = 0.95 and 0.78, respectively). Within the Aquia aquifer, however, W generally occurs at lower concentrations than the Carrizo (14 to 184 pmol/kg; mean = 80 pmol/kg), and shows no systematic trends along the flow path (e.g., r = 0.08 and 0.4 for W vs. S(-II) and pH, respectively). Our data are consistent with the increase in W concentrations in Carrizo groundwaters reflecting, in part, pH-related desorption, which has been shown to be substantial for pH greater than 8. Moreover, because of the broad similarities in the chemistry of W and Mo, which forms thiomolybdates in sulfidic waters, we suggest that thiotungstate complexes may form in sulfidic groundwaters, thus partially explaining the

  8. Groundwater flow in a coastal peatland and its influence on submarine groundwater discharge

    Science.gov (United States)

    Ptak, T.; Ibenthal, M.; Janssen, M.; Massmann, G.; Lenartz, B.

    2017-12-01

    Coastal peatlands are characterized by intense interactions between land and sea, comprising both a submarine discharge of fresh groundwater and inundations of the peatland with seawater. Nutrients and salts can influence the biogeochemical processes both in the shallow marine sediments and in the peatland. The determination of flow direction and quantity of groundwater flow are therefore elementary. Submarine groundwater discharge (SGD) has been reported from several locations in the Baltic. The objective of this study is to quantify the exchange of fresh and brackish water across the shoreline in a coastal peatland in Northeastern Germany, and to assess the influence of a peat layer extending into the Baltic Sea. Below the peatland, a shallow fine sand aquifer differs in depth and is limited downwards by glacial till. Water level and electrical conductivity (EC) are permanently measured in different depths at eight locations in the peatland. First results indicate a general groundwater flow direction towards the sea. Electrical conductivity measurements suggest different permeabilities within the peat layer, depending on its thickness and degradation. Near the beach, EC fluctuates partially during storm events due to seawater intrusion and reverse discharge afterwards. The groundwater flow will be verified with a 3D model considering varying thicknesses of the aquifer. Permanent water level and electrical conductivity readings, meteorological data and hydraulic conductivity from slug tests and grain size analysis are the base for the calibration of the numerical model.

  9. Simulation of groundwater flows in unsaturated porous media

    International Nuclear Information System (INIS)

    Musy, A.

    1976-01-01

    Groundwater flow in unsaturated porous media is caused by a potential gradient where the total potential consists of the sum of a gravitational and a suction component. The partial differential equations which result from the general analysis of groundwater flow in unsaturated soil are solved by succesive approximations with the finite-element method. General boundary and initial conditions, linear or curvilinear shaped elements (isoparametric elements) and steady-state or transient flow can be introduced into the numerical computer program. The results of this mathematical model are compared with experimental data established in the laboratory with a physical groundwater model. This is a rectangular testing tank of dimension 3 x 1.5 x 0.15 m and contains a silty clay loam. The variation of the bulk density and the volumetric moisture of the soil as a function of time and space are measured by gamma absorption from a 137 Cs source with 300 mCi intensity

  10. A report on intercomparison studies of computer programs which respectively model: i) radionuclide migration ii) equilibrium chemistry of groundwater

    International Nuclear Information System (INIS)

    Broyd, T.W.; McD Grant, M.; Cross, J.E.

    1985-01-01

    This report describes two intercomparison studies of computer programs which respectively model: i) radionuclide migration ii) equilibrium chemistry of groundwaters. These studies have been performed by running a series of test cases with each program and comparing the various results obtained. The work forms a part of the CEC MIRAGE project (MIgration of RAdionuclides in the GEosphere) and has been jointly funded by the CEC and the United Kingdom Department of the Environment. Presentations of the material contained herein were given at plenary meetings of the MIRAGE project in Brussels in March, 1984 (migration) and March, 1985 (equilibrium chemistry) respectively

  11. Complex groundwater flow systems as traveling agent models

    Directory of Open Access Journals (Sweden)

    Oliver López Corona

    2014-10-01

    Full Text Available Analyzing field data from pumping tests, we show that as with many other natural phenomena, groundwater flow exhibits complex dynamics described by 1/f power spectrum. This result is theoretically studied within an agent perspective. Using a traveling agent model, we prove that this statistical behavior emerges when the medium is complex. Some heuristic reasoning is provided to justify both spatial and dynamic complexity, as the result of the superposition of an infinite number of stochastic processes. Even more, we show that this implies that non-Kolmogorovian probability is needed for its study, and provide a set of new partial differential equations for groundwater flow.

  12. A Method to Evaluate Groundwater flow system under the Seabed

    Science.gov (United States)

    Kohara, N.; Marui, A.

    2011-12-01

    / fresh water interface (position of the submarine groundwater discharge) may appear on the seafloor. Moreover, neither the salinity concentration nor the groundwater age depends on depth. It is thought that it is because that the groundwater forms the complex flow situation through the change in a long-term groundwater flow system. The technology to understand the coastal groundwater flow consists of remote sensing, geographical features analysis, surface of the earth investigation, geophysical exploration, drilling survey, and indoor examination and the measurement. Integration of each technology is needed to interpret groundwater flow system because the one is to catch the local groundwater flow in the time series and another one is to catch the long-term and regional groundwater flow in the general situation. The purpose of this study is to review the previous research of coastal groundwater flow, and to integrate an applicable evaluation approach to understand this mechanism. In this presentation, the review of the research and case study using numerical simulation are introduced.

  13. Ground-water flow and transport modeling of the NRC-licensed waste disposal facility, West Valley, New York

    International Nuclear Information System (INIS)

    Kool, J.B.; Wu, Y.S.

    1991-10-01

    This report describes a simulation study of groundwater flow and radionuclide transport from disposal at the NRC licensed waste disposal facility in West Valley, New York. A transient, precipitation driven, flow model of the near-surface fractured till layer and underlying unweathered till was developed and calibrated against observed inflow data into a recently constructed interceptor trench for the period March--May 1990. The results suggest that lateral flow through the upper, fractured till layer may be more significant than indicated by previous, steady state flow modeling studies. A conclusive assessment of the actual magnitude of lateral flow through the fractured till could however not be made. A primary factor contributing to this uncertainty is the unknown contribution of vertical infiltration through the interceptor trench cap to the total trench inflow. The second part of the investigation involved simulation of the migration of Sr-90, Cs-137 and Pu-239 from the one of the fuel hull disposal pits. A first-order radionuclide leach rate with rate coefficient of 10 -6 /day was assumed to describe radionuclide release into the disposal pit. The simulations indicated that for wastes buried below the fractured till zone, no significant migration would occur. However, under the assumed conditions, significant lateral migration could occur for radionuclides present in the upper, fractured till zone. 23 refs., 68 figs., 12 tabs

  14. Determination of groundwater flow velocity by radon measurements

    International Nuclear Information System (INIS)

    Hohn, E.; von Gunten, H.R.

    1990-01-01

    The groundwater resources of glacio-fluvial perialpine valleys are recharged significantly by the infiltration from rivers. The groundwater residence times between rivers and wells should be known in groundwater management problems. Short residence times can be estimated using radon. Radon concentrations in rivers are usually very low. Upon filtration and movement of the water in the ground, radon is picked up and its concentration increases by 2-3 orders of magnitude according to radioactive growth laws. Residence times and flow velocities can be estimated from the increasing radon concentrations measured in groundwater sampling tubes at different distances from the river. Results obtained with this method agree with the results from experiments with artificial tracers

  15. Characterization of groundwater flow in the environment of the Boom Clay (Campine, Belgium)

    International Nuclear Information System (INIS)

    Gedeon, M.; Labat, S.; Wemaere, I.; Wouters, L.

    2010-01-01

    Document available in extended abstract form only. In Belgium, the Boom Clay formation is considered as reference host rock for the geological disposal of radioactive waste. Aquifers surrounding the Boom Clay play a passive role in the context of the disposal safety whereby the radionuclides are diluted by groundwater flow. The groundwater flow in these aquifers has been studied since decades. This research involves observations of groundwater levels in the regional and local piezo-metric networks, several site investigations including geophysics and core-drilled boreholes and groundwater modelling. In this context, groundwater modelling represents the integration of the site characterization efforts and provides a comprehensive tool for constraining the models used in the safety assessment of the geological disposal. Since 1985, groundwater levels are observed monthly in the regional piezo-metric network. It consists of 142 filters monitoring the groundwater levels at 45 sites. Along with the observed groundwater levels from the local piezo-metric network (concentrated around the Mol-Dessel site for surface disposal), these data provide an excellent insight into the evolution of the groundwater levels. Moreover, they represent a calibration (validation) dataset for groundwater flow modelling. The groundwater system forming the environment of the Boom Clay host rock was characterized during several site investigation campaigns, within which seven core-drilled boreholes were realized, whereby hydraulic parameters and hydro-stratigraphy of the groundwater system could be collected. The dataset obtained from the above mentioned campaigns was complemented by archived data on hydraulic testing in the aquifers in order to build a comprehensive groundwater model integrating these data into a single numerical representation of the groundwater system. Three regional groundwater models have been developed integrating the site characterization data collected in the north

  16. Heat and Groundwater Flow in the San Gabriel Mountains, California

    Science.gov (United States)

    Newman, A. A.; Becker, M.; Laton, W. R., Jr.

    2017-12-01

    Groundwater flow paths in mountainous terrain often vary widely in both time and space. Such systems remain difficult to characterize due to fracture-dominated flow paths, high topographic relief, and sparse hydrologic data. We develop a hydrogeologic conceptual model of the Western San Gabriel Mountains in Southern California based on geophysical, thermal, and hydraulic head data. Boreholes are located along the San Gabriel Fault Zone (SGFZ) and cover a wide range of elevations to capture the heterogeneity of the hydrogeologic system. Long term (2016-2017) monitoring of temperature and hydraulic head was carried out in four shallow (300-600m depth) boreholes within the study area using fiber-optic distributed temperature sensing (DTS). Borehole temperature profiles were used to assess the regional groundwater flow system and local flows in fractures intersecting the borehole. DTS temperature profiles were compared with available borehole geophysical logs and head measurements collected with grouted vibrating wire pressure transducers (VWPT). Spatial and temporal variations in borehole temperature profiles suggest that advective heat transfer due to fluid flow affected the subsurface thermal regime. Thermal evidence of groundwater recharge and/or discharge and flow through discrete fractures was found in all four boreholes. Analysis of temporal changes to the flow system in response to seasonal and drilling-induced hydraulic forcing was useful in reducing ambiguities in noisy datasets and estimating interborehole relationships. Acoustic televiewer logs indicate fractures were primarily concentrated in densely fractured intervals, and only a minor decrease of fracture density was observed with depth. Anomalously high hydraulic gradients across the SGFZ suggest that the feature is a potential barrier to lateral flow. However, transient thermal anomalies consistent with groundwater flow within the SGFZ indicate this feature may be a potential conduit to vertical flow

  17. Application of artificial radioactive tracers for groundwater flow

    International Nuclear Information System (INIS)

    Hamza, M.S.; Aly, A.I.M.; Swailem, F.M.; Nada, A.A.; Awad, M.A.

    1989-01-01

    In this work, the groundwater velocity was estimated by applying radioactive tracer techniques: the single well and the multiple well methods. In the first single well method, radioactive iodine-131 was injected in the well and the radioactivity was monitored with time. The groundwater flow was estimated as a function of the concentration dilution factor of the tracer taking into consideration the permeability of the filter screen and the aquifer. The second method (the multiple well technique) is based on direct measuring of the period of time the tracer needs to disperse from the injection well to one of receptor well arranged in a circle around the injection. The latter method was found to be more accurate and reliable and has also the advantage of determining the groundwater velocity and direction of flow as well. The limitations of the single well technique are discussed and a detailed comparison between single and multi-well techniques is given

  18. Groundwater flow and sorption processes in fractured rocks (I)

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Won Young; Woo, Nam Chul; Yum, Byoung Woo; Choi, Young Sub; Chae, Byoung Kon; Kim, Jung Yul; Kim, Yoo Sung; Hyun, Hye Ja; Lee, Kil Yong; Lee, Seung Gu; Youn, Youn Yul; Choon, Sang Ki [Korea Institute of Geology Mining and Materials, Taejon (Korea, Republic of)

    1996-12-01

    This study is objected to characterize groundwater flow and sorption processes of the contaminants (ground-water solutes) along the fractured crystalline rocks in Korea. Considering that crystalline rock mass is an essential condition for using underground space cannot be overemphasized the significance of the characterizing fractured crystalline rocks. the behavior of the groundwater contaminants is studied in related to the subsurface structure, and eventually a quantitative technique will be developed to evaluate the impacts of the contaminants on the subsurface environments. The study has been carried at the Samkwang mine area in the Chung-Nam Province. The site has Pre-Cambrian crystalline gneiss as a bedrock and the groundwater flow system through the bedrock fractures seemed to be understandable with the study on the subsurface geologic structure through the mining tunnels. Borehole tests included core logging, televiewer logging, constant pressure fixed interval length tests and tracer tests. The results is summarized as follows; 1) To determine the hydraulic parameters of the fractured rock, the transient flow analysis produce better results than the steady - state flow analysis. 2) Based on the relationship between fracture distribution and transmissivities measured, the shallow part of the system could be considered as a porous and continuous medium due to the well developed fractures and weathering. However, the deeper part shows flow characteristics of the fracture dominant system, satisfying the assumptions of the Cubic law. 3) Transmissivities from the FIL test were averaged to be 6.12 x 10{sup -7}{sub m}{sup 2}{sub /s}. 4) Tracer tests result indicates groundwater flow in the study area is controlled by the connection, extension and geometry of fractures in the bedrock. 5) Hydraulic conductivity of the tracer-test interval was in maximum of 7.2 x 10{sup -6}{sub m/sec}, and the effective porosity of 1.8 %. 6) Composition of the groundwater varies

  19. Detect groundwater flowing from riverbed using a drone

    Science.gov (United States)

    Kato, Kenji; Takemon, Yasuhiro

    2017-04-01

    Estimate the direct flow of groundwater to river is an important step in understanding of hydrodynamics in river system. Function of groundwater in river system does not limit to the mass of water. Continuous supply with thermally stable water from riverbed produces a space with unique condition, which provides various functions for organisms inhabiting in river as a shelter avoiding large shift of temperature, or to maintain productivity for small scale ecosystem by supplying nutrient rich groundwater if it gushes out from the riverbed in a deep pool of river. This may contribute to biodiversity of river system. Such function of groundwater is more significant for rivers run in island and in mountain zone. To evaluate the function of groundwater flowing from riverbed we first try to find such site by using a drone equipped with a sensitive thermo-camera to detect water surface temperature. In the examined area temperature of the groundwater doesn't change much throughout a year at around 15 to 16 °C, while surface temperature of the examined river fluctuates from below 10 °C to over 25 °C throughout seasons. By using this difference in temperature between groundwater and river water we tried to find site where groundwater comes out from the riverbed. Obviously winter when surface temperature becomes below 10 °C is an appropriate season to find groundwater as it comes up to the surface of river with depth ranging from 1 to 3 m. Trial flight surveys of drone were conducted in Kano-river in Izu Peninsula located at southern foot of Mt. Fuji in central Japan. Employed drone was Inspire1 (DJI, China) equipped with a Thermal camera (Zenmuse XT ZXTA 19 FP, FLIR, USA) and operated by Kazuhide Juta (KELEK Co. Ltd., Japan) and Mitsuhiro Komiya (TAM.Co.,LTD). In contrast to the former cases with employing airplane for taking aerial photograph, drone takes photo while flying at a low-altitude. When it flies at 40m above the water surface of river, resolution is at an

  20. A basis for modelling of radionuclide flow in the Forsmark biotest basin

    International Nuclear Information System (INIS)

    Notter, M.; Snoeijs, P.; Argaerde, L.; Elert, M.

    1987-01-01

    Certain radionuclides are discharged together with the cooling water of Forsmark power station. Of these, Mn-54, Co-60, Zn-65 and Ag-110 m are easily detectable in the environment. This report gives a conceptual five-compartment model for the flows of radionuclides within the basin ecosystem. The available data from biological and radio-ecological investigations in the biotest basin were used to quantify the amounts of radionuclides in each of the reservoirs. The subsystem water-sediment-primary producers was pointed out to be the most interesting part of the ecosystem for studying radionuclides with mathematical modelling in the future. (orig./DG)

  1. Colloid migration in groundwaters: Geochemical interactions of radionuclides with natural colloids. 5. progress report. Period covered: July - December 1993

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J.I. [Technische Univ. Muenchen, Garching (Germany); Delakowitz, B. [Technische Univ. Muenchen, Garching (Germany); Zeh, P. [Technische Univ. Muenchen, Garching (Germany); Probst, T. [Technische Univ. Muenchen, Garching (Germany); Lin, X. [Technische Univ. Muenchen, Garching (Germany); Ehrlicher, U. [Technische Univ. Muenchen, Garching (Germany); Schauer, C. [Technische Univ. Muenchen, Garching (Germany); Ivanovich, M. [Harwell Lab., AEA Environment and Energy, Oxon (United Kingdom); Longworth, G. [Harwell Lab., AEA Environment and Energy, Oxon (United Kingdom); Hasler, S.E. [Harwell Lab., AEA Environment and Energy, Oxon (United Kingdom); Gardiner, M. [Harwell Lab., AEA Decommissioning and RadWaste, Oxon (United Kingdom); Fritz, P. [GSF - Forschungszentrum fuer Umwelt und Gesundheit GmbH, Neuherberg (Germany); Klotz, D. [GSF - Forschungszentrum fuer Umwelt und Gesundheit GmbH, Neuherberg (Germany); Lazik, D. [GSF - Forschungszentrum fuer Umwelt und Gesundheit GmbH, Neuherberg (Germany); Wolf, M. [GSF - Forschungszentrum fuer Umwelt und Gesundheit GmbH, Neuherberg (Germany); Geyer, S. [GSF - Forschungszentrum fuer Umwelt und Gesundheit GmbH, Neuherberg (Germany); Alexander, J.L. [Atkins (W.S.) Engineering Sciences, Epsom (United Kingdom); Read, D. [Atkins (W.S.) Engineering Sciences, Epsom (United Kingdom); Thomas, J.B. [Atkins (W.S.) Engineering Sciences, Epsom (United Kingdom)

    1994-02-01

    The aim of the joint research programme is to determine the significance of groundwater colloids in far field radionuclide migration. The characterization, quantification and theoretical interpretation of colloid-borne transport phenomena of radionuclides in selected Gorleben aquifer systems are the main objectives of the present research programme. Gorleben aquifer systems are chosen because they are well characterized in terms of their hydrological and geological properties and because they contain substantial amounts of colloids of different chemical compositions as well as considerable quantities of chemical homologues and natural analogues of radionuclides, e.g. M(III), M(IV), M(VI), and Th and U decay series. The research tasks are investigated jointly by the four laboratories (listed below) in close coordination of experimental capacities of each laboratory. (orig.)

  2. Validation on groundwater flow model including sea level change. Modeling on groundwater flow in coastal granite area

    International Nuclear Information System (INIS)

    Hasegawa, Takuma; Miyakawa, Kimio

    2009-01-01

    It is important to verify the groundwater flow model that reproduces pressure head, water chemistry, and groundwater age. However, water chemistry and groundwater age are considered to be influenced by historical events. In this study, sea level change during glacial-interglacial cycle was taken into account for simulating salinity and groundwater age at coastal granite area. As a result of simulation, salinity movement could not catch up with sea level changes, and mixing zone was formed below the fresh-water zone. This mixing zone was observed in the field measurement, and the observed salinities were agreed with simulated results including sea level change. The simulated residence time including sea level change is one-tenth of steady state. The reason is that the saline water was washed out during regression and modern sea-water was infiltrated during transgression. As mentioned before, considering sea level change are important to reproduce salinity and helium age at coastal area. (author)

  3. Transport of radionuclides by bentonite and silica colloids in a GR-3 synthetic groundwater-interim report

    International Nuclear Information System (INIS)

    Ames, L.L.; McGarrah, J.E.; Walker, B.A.

    1983-08-01

    Radionuclide distributions in groundwater-colloid-basalt systems were measured using GR-3 groundwater and crushed Umtanum basalt at 60 degree C. The objective was to estimate the potential for radionuclide transport from a nuclear waste repository in basalt by colloids suspended in groundwater. Three colloids were studied -- a bentonite colloid representing a potential component of packing or backfill materials in the repository, and two hydrated silica colloids which might represent those generated from a glass waste form. The radioelements studied included isotopes of neptunium, uranium, selenium, technetium, and radium. Measurements of radionuclide distributions in experiments with the bentonite colloid showed that uranium was sorbed strongly on the colloid (under both oxidizing and reducing conditions) but was readily transferred to basalt when it was added to the system. Sorption of neptunium, technetium, and selenium on the colloid was greatly enhanced by using reducing conditions. Only small amounts of neptunium and technetium were transferred to the basalt under reducing conditions, but most of the selenium was readily transferred under these conditions

  4. The effects of radiogenic heat on groundwater flow

    International Nuclear Information System (INIS)

    Beddoes, R.J.; Tammemagi, H.Y.

    1986-03-01

    The effects of radiogenic heat released by a nuclear waste repository on the groundwater flow in the neighbouring rock mass is reviewed. The report presents an overview of the hydrogeologic properties of crystalline rocks in the Canadian Shield and also describes the mathematical theory of groundwater flow and heat transfer in both porous media and fractured rock. Numerical methods for the solution of the governing equations are described. A number of case histories are described where analyses of flow systems have been performed both with and without radiogenic heat sources. A number of relevant topics are reviewed such as the role of the porous medium model, boundary conditions and, most importantly, the role of complex coupled processes where the effects of heat and water flow are intertwined with geochemical and mechanical processes. The implications to radioactive waste disposal are discussed

  5. Unsaturated-zone fast-path flow calculations for Yucca Mountain groundwater travel time analyses (GWTT-94)

    International Nuclear Information System (INIS)

    Arnold, B.W.; Altman, S.J.; Robey, T.H.

    1995-08-01

    Evaluation of groundwater travel time (GWTT) is required as part of the investigation of the suitability of Yucca Mountain as a potential high-level nuclear-waste repository site. The Nuclear Regulatory Commission's GWTT regulation is considered to be a measure of the intrinsic ability of the site to contain radionuclide releases from the repository. The work reported here is the first step in a program to provide an estimate of GWTT at the Yucca Mountain site in support of the DOE's Technical Site Suitability and as a component of a license application. Preliminary estimation of the GWTT distribution in the unsaturated zone was accomplished using a numerical model of the physical processes of groundwater flow in the fractured, porous medium of the bedrock. Based on prior investigations of groundwater flow at the site, fractures are thought to provide the fastest paths for groundwater flow; conditions that lead to flow in fractures were investigated and simulated. Uncertainty in the geologic interpretation of Yucca Mountain was incorporated through the use of geostatistical simulations, while variability of hydrogeologic parameters within each unit was accounted for by the random sampling of parameter probability density functions. The composite-porosity formulation of groundwater flow was employed to simulate flow in both the matrix and fracture domains. In this conceptualization, the occurrence of locally saturated conditions within the unsaturated zone is responsible for the initiation of fast-path flow through fractures. The results of the GWTT-94 study show that heterogeneity in the hydraulic properties of the model domain is an important factor in simulating local regions of high groundwater saturation. Capillary-pressure conditions at the surface boundary influence the extent of the local saturation simulated

  6. Groundwater flow model and its implications for contaminant behavior

    African Journals Online (AJOL)

    What sets hydrogeology apart from many of the other geosciences is an emphasis on treating problems mathematically. The mathematical approach involves representing a groundwater process by an equation and solving that equation. These equations are fundamental to the quantitative treatment of flow and provide the ...

  7. Investigation of groundwater flow potential in Makurdi, North Central ...

    African Journals Online (AJOL)

    hp

    Department of Physics and Astronomy, University of Nigeria, Nsukka, Nigeria. Received 6 August, 2015; ... order to study the groundwater flow potential in Makurdi, north central Nigeria. This was done in thirty .... 600 m above sea level. The drainage consists ..... engineering Studies: A Practical Guide to 2D and 3D Surveys.

  8. The deep hydrogeologic flow system underlying the Oak Ridge Reservation - Assessing the potential for active groundwater flow and origin of the brine

    International Nuclear Information System (INIS)

    Nativ, R.; Halleran, A.; Hunley, A.

    1997-08-01

    The deep hydrogeologic system underlying the Oak Ridge Reservation (ORR) contains contaminants such as radionuclides, heavy metals, nitrates, and organic compounds. The groundwater in the deep system is saline and has been considered to be stagnant in previous studies. This study was designed to address the following questions: is groundwater in the deep system stagnant; is contaminant migration controlled by diffusion only or is advection a viable mechanism; where are the potential outlet points? On the basis of existing and newly collected data, the nature of saline groundwater flow and potential discharge into shallow, freshwater systems was assessed. Data used for this purpose included (1) spatial and temporal pressures and hydraulic heads measured in the deep system, (2) hydraulic parameters of the formations in question, (3) spatial and temporal temperature variations at depth, and (4) spatial and temporal chemical and isotopic composition of the saline groundwater. The observations suggest that the saline water contained at depth is old but not isolated (in terms of recharge and discharge) from the overlying active, freshwater-bearing units. Influx of recent water does occur. Groundwater volumes involved in this flow are likely to be small. The origin of the saline groundwater was assessed by using existing and newly acquired chemical and isotopic data. The proposed model that best fits the data is modification of residual brine from which halite has been precipitated. Other models, such as ultrafiltration and halite dissolution, were also evaluated

  9. Radionuclide transfer onto ground surface in surface water flow. 2. Undisturbed tuff rock

    International Nuclear Information System (INIS)

    Mukai, Masayuki; Takebe, Shinichi; Komiya, Tomokazu

    1994-09-01

    Radionuclide migration with ground surface water flow is considered to be one of path ways in the scenario for environmental migration of the radionuclide leaked from LLRW depository. To study the radionuclide migration demonstratively, a ground surface radionuclide migration test was carried out by simulating radioactive solution flowing on the sloped tuff rock surface. Tuff rock sample of 240 cm in length taken from the Shimokita district was used to test the transfer of 60 Co, 85 Sr and 137 Cs onto the sample surface from the flowing radioactive solution under restricted infiltration condition at flow rates of 25, 80, 160ml/min and duration of 56h. The concentration change of the radionuclides in effluent was nearly constant as a function of elapsed time during the experimental period, but decreased with lower flow rates. Among the three radionuclides, 137 Cs was greatly decreased its concentration to 30% of the inflow. Adsorbed distribution of the radionuclides concentration on the ground surface decreased gradually with the distance from the inlet, and showed greater gradient at lower flow rate. Analyzing the result by the migration model, where a vertical advection distribution and two-dimensional diffusion in surface water are adopted with a first order adsorption reaction, value of migration parameters was obtained relating to the radionuclide adsorption and the surface water flow, and the measured distribution could be well simulated by adopting the value to the model. By comparing the values with the case of loamy soil layer, all values of the migration parameters showed not so great difference between two samples for 60 Co and 85 Sr. For 137 Cs, reflecting a few larger value of adsorption to the tuff rock, larger ability to reduce the concentration of flowing radioactive solution could be indicated than that to the loamy soil surface by estimation for long flowed distance. (author)

  10. Ambient groundwater flow diminishes nitrogen cycling in streams

    Science.gov (United States)

    Azizian, M.; Grant, S. B.; Rippy, M.; Detwiler, R. L.; Boano, F.; Cook, P. L. M.

    2017-12-01

    Modeling and experimental studies demonstrate that ambient groundwater reduces hyporheic exchange, but the implications of this observation for stream N-cycling is not yet clear. We utilized a simple process-based model (the Pumping and Streamline Segregation or PASS model) to evaluate N- cycling over two scales of hyporheic exchange (fluvial ripples and riffle-pool sequences), ten ambient groundwater and stream flow scenarios (five gaining and losing conditions and two stream discharges), and three biogeochemical settings (identified based on a principal component analysis of previously published measurements in streams throughout the United States). Model-data comparisons indicate that our model provides realistic estimates for direct denitrification of stream nitrate, but overpredicts nitrification and coupled nitrification-denitrification. Riffle-pool sequences are responsible for most of the N-processing, despite the fact that fluvial ripples generate 3-11 times more hyporheic exchange flux. Across all scenarios, hyporheic exchange flux and the Damkohler Number emerge as primary controls on stream N-cycling; the former regulates trafficking of nutrients and oxygen across the sediment-water interface, while the latter quantifies the relative rates of organic carbon mineralization and advective transport in streambed sediments. Vertical groundwater flux modulates both of these master variables in ways that tend to diminish stream N-cycling. Thus, anthropogenic perturbations of ambient groundwater flows (e.g., by urbanization, agricultural activities, groundwater mining, and/or climate change) may compromise some of the key ecosystem services provided by streams.

  11. Site scale groundwater flow in Olkiluoto - complementary simulations

    International Nuclear Information System (INIS)

    Loefman, J.

    2000-06-01

    This work comprises of the complementary simulations to the previous groundwater flow analysis at the Olkiluoto site. The objective is to study the effects of flow porosity, conceptual model for solute transport, fracture zones, land uplift and initial conditions on the results. The numerical simulations are carried out up to 10000 years into the future employing the same modelling approach and site-specific flow and transport model as in the previous work except for the differences in the case descriptions. The result quantities considered are the salinity and the driving force in the vicinity of the repository. The salinity field and the driving force are sensitive to the flow porosity and the conceptual model for solute transport. Ten-fold flow porosity and the dual-porosity approach retard the transport of solutes in the bedrock resulting in brackish groundwater conditions at the repository at 10000 years A.P. (in the previous work the groundwater in the repository turned into fresh). The higher driving forces can be attributed to the higher concentration gradients resulting from the opposite effects of the land uplift, which pushes fresh water deeper and deeper into the bedrock, and the higher flow porosity and the dual-porosity model, which retard the transport of solutes. The cases computed (unrealistically) without fracture zones and postglacial land uplift show that they both have effect on the results and can not be ignored in the coupled and transient groundwater flow analyses. The salinity field and the driving force are also sensitive to the initial salinity field especially at the beginning during the first 500 years A.P. The sensitivity will, however, diminish as soon as fresh water dilutes brackish and saline water and decreases the concentration gradients. Fresh water conditions result in also a steady state for the driving force in the repository area. (orig.)

  12. Groundwater flow analysis on local scale. Setting boundary conditions for groundwater flow analysis on site scale model in step 1

    International Nuclear Information System (INIS)

    Ohyama, Takuya; Saegusa, Hiromitsu; Onoe, Hironori

    2005-05-01

    Japan Nuclear Cycle Development Institute has been conducting a wide range of geoscientific research in order to build a foundation for multidisciplinary studies of the deep geological environment as a basis of research and development for geological disposal of nuclear wastes. Ongoing geoscientific research programs include the Regional Hydrogeological Study (RHS) project and Mizunami Underground Research Laboratory (MIU) project in the Tono region, Gifu Prefecture. The main goal of these projects is to establish comprehensive techniques for investigation, analysis, and assessment of the deep geological environment at several spatial scales. The RHS project is a local scale study for understanding the groundwater flow system from the recharge area to the discharge area. The surface-based Investigation Phase of the MIU project is a site scale study for understanding the groundwater flow system immediately surrounding the MIU construction site. The MIU project is being conducted using a multiphase, iterative approach. In this study, the hydrogeological modeling and groundwater flow analysis of the local scale were carried out in order to set boundary conditions of the site scale model based on the data obtained from surface-based investigations in Step 1 in site scale of the MIU project. As a result of the study, head distribution to set boundary conditions for groundwater flow analysis on the site scale model could be obtained. (author)

  13. Groundwater flow and mixing in a wetland–stream system

    DEFF Research Database (Denmark)

    Karan, Sachin; Engesgaard, Peter Knudegaard; Zibar, Majken Caroline Looms

    2013-01-01

    steady-state groundwater model that was calibrated against average head observations. The model results were tested against groundwater fluxes determined from streambed temperature measurements. Discharge varied up to one order of magnitude across the stream and the model was successful in capturing...... in the top of the aquifer and immediately underneath the streambed no NO3- was detected deeper within the aquifer. An inverse relationship between NO3- and SO42- suggests that pyrite oxidation takes place in the deeper parts of the aquifer. Simulated flow path lines showed very different origins for deeper...

  14. Sources and flow of north Canterbury Plains groundwater, New Zealand

    International Nuclear Information System (INIS)

    Taylor, C.B.; Brown, L.J.; Stewart, M.K.; Brailsford, G.W.; Wilson, D.D.; Burden, R.J.

    1989-01-01

    Geological, hydrological, isotope (tritium and 18 O) and chemical evidence is interpreted to give a mutually consistent picture of the recharge sources and flow patterns of the important groundwater resource in the deep Quaternary deposits of the Canterbury Plains between Selwyn R. and Ashley R. The study period for tritium measurements extends over 27 years, encompassing the peak and decline of thermonuclear tritium fallout in this region. Major rivers emerging from mountain catchments to the west of the Plains are depleted in 18 O relative to average low-level precipitation. Most of the groundwater is river-recharged, but some areas with significant local precipitation recharge are clearly identified by 18 O and chemical concentrations. Artesian groundwater underlying Christchurch ascends from deeper aquifers into the shallowest aquifer via gaps in the confining layers; much of this flow is induced by withdrawal. The Christchurch aquifers are recharged by infiltration from Waimakariri R. in its central Plains reaches, and the resulting flow regime is E- and SE-directed; satisfactory water quality of the deeper Christchurch aquifer appears to be guaranteed for the future provided the river can be maintained in its present condition. Shallow groundwater, and water recharged to depth by other rivers, irrigation and local precipitation on the unconfined western areas of the Plains, are more susceptible to agricultural and other pollutants; none of this water is encountered in the deeper aquifers under Christchurch. (author). 15 refs., 12 figs

  15. Groundwater availability as constrained by hydrogeology and environmental flows.

    Science.gov (United States)

    Watson, Katelyn A; Mayer, Alex S; Reeves, Howard W

    2014-01-01

    Groundwater pumping from aquifers in hydraulic connection with nearby streams has the potential to cause adverse impacts by decreasing flows to levels below those necessary to maintain aquatic ecosystems. The recent passage of the Great Lakes-St. Lawrence River Basin Water Resources Compact has brought attention to this issue in the Great Lakes region. In particular, the legislation requires the Great Lakes states to enact measures for limiting water withdrawals that can cause adverse ecosystem impacts. This study explores how both hydrogeologic and environmental flow limitations may constrain groundwater availability in the Great Lakes Basin. A methodology for calculating maximum allowable pumping rates is presented. Groundwater availability across the basin may be constrained by a combination of hydrogeologic yield and environmental flow limitations varying over both local and regional scales. The results are sensitive to factors such as pumping time, regional and local hydrogeology, streambed conductance, and streamflow depletion limits. Understanding how these restrictions constrain groundwater usage and which hydrogeologic characteristics and spatial variables have the most influence on potential streamflow depletions has important water resources policy and management implications. © 2013, National Ground Water Association.

  16. Study on groundwater flow system in a sedimentary rock area. Case study for the Yoro river basin, Chiba Prefecture

    International Nuclear Information System (INIS)

    Sakai, Ryutaro; Munakata, Masahiro; Kimura, Hideo

    2007-01-01

    In the safety assessment for a geological disposal of long-lived radioactive waste such as high-level radioactive waste and TRU waste etc, it is important to estimate radionuclide migration to human society associated with groundwater flow. Groundwater flow systems for many domestic areas including Tono Mine, Kamaishi Mine and Horonobe district have been studied, but deep groundwater flow circumstances, and mixing between deep groundwater and shallow groundwater flow system are not well understood. Japan Atomic Energy Agency (JAEA) has started to investigate a sedimentary rock area in the Yoro river basin, in Chiba Prefecture, where the topographic and geological features are relatively simple for mathematical modeling, and hydraulic data as well as data from river and well water are available. Hydro-chemical conditions of the regional groundwater were discussed based on temperature, chemical compositions, isotopic ratios of hydrogen and oxygen, and the isotopic age of radioactive carbon for water samples collected from wells, rivers and springs in the Yoro river basin. It was found that the groundwater system in this basin consists of types of water: Ca-HCO 3 type water, Na-HCO 3 type water and NaCl type water. The Ca-HCO 3 type water is meteoric water cultivated several thousand years or after, the Na-HCO 3 type water is meteoric water cultivated under cold climates several to twenty thousand years ago. The NaCl type water is fossil brine water formed twenty thousand years ago. It was also observed that the Na-HCO 3 type water upwelled at the surface originates from GL-200m to -400m. This observation indicates that the Na-HCO 3 type water upwelled through the Ca-HCO 3 type water area with the both waters partially mixed. (author)

  17. Microbes Characteristics in Groundwater Flow System in Mountainous Area

    Science.gov (United States)

    Yamamoto, Chisato; Tsujimura, Maki; Kato, Kenji; Sakakibara, Koichi; Ogawa, Mahiro; Sugiyama, Ayumi; Nagaosa, Kazuyo

    2017-04-01

    We focus on a possibility of microbes as a tracer for groundwater flow investigation. Some previous papers showed that the total number of prokaryotes in groundwater has correlation with depth and geology (Parkes et al., 1994; Griebler et al., 2009; Kato et al., 2012). However, there are few studies investigating both microbe characteristics and groundwater flow system. Therefore, we investigated a relationship between the total number of prokaryotes and age of spring water and groundwater. Intensive field survey was conducted at four mountainous areas, namely Mt. Fuji (volcano), a headwater at Mt. Setohachi, a headwater at River Oi and a headwater at River Nagano underlain by volcanic lava at Mt. Fuji, granite at Mt. Setohachi and sedimentary rock at River Oi and River Nagano. We collected totally 40 spring water/ groundwater samples in these mountainous areas in October 2015, August, October and November 2016 and analyzed concentration of inorganic ions, the stable isotopes of oxygen - 18, deuterium, CFCs and SF6. Also, we counted prokaryotic cells under the epifluorescence microscopy after fixation and filteration. The total number of prokaryotes in the spring water/ groundwater ranged from 1.0×102 to 7.0×103cells mL-1 at the Mt. Fuji, 1.3×104 to 2.7×105cells mL-1 at Mt. Setohachi, 3.1×104cells mL-1 at River Oi and 1.8×105 to 3.2×106cells mL-1 at River Nagano. The SF6 age of the spring water/ groundwater ranged from 8 to 64 years at Mt. Fuji, 2 to 32.5 years at Mt. Setohachi, 2.5 years at River Oi and 15 to 16 years at River Nagano. The total number of prokaryotes showed a clear negative correlation with residence time of spring water/ groundwater in all regions. Especially the prokaryotes number increased in the order of 102 cells mL-1 with decreasing of residence time in approximately 10 years in the groundwater and spring water with the age less than 15 years.

  18. Incorporating groundwater flow into the WEPP model

    Science.gov (United States)

    William Elliot; Erin Brooks; Tim Link; Sue Miller

    2010-01-01

    The water erosion prediction project (WEPP) model is a physically-based hydrology and erosion model. In recent years, the hydrology prediction within the model has been improved for forest watershed modeling by incorporating shallow lateral flow into watershed runoff prediction. This has greatly improved WEPP's hydrologic performance on small watersheds with...

  19. Tracer techniques for determination of groundwater flow parameters

    International Nuclear Information System (INIS)

    Drost, W.; Klotz, D.

    1988-05-01

    The most common one-borehole and multiple borehole methods using tracers for the direct determination of the groundwater flow parameters (velocity of flow, flow direction) and for the indirect determination of characteristic quantities of the aquifer (effective porosity, dispersivity, transmissivity) are presented methodically and their value is documented by practical examples. Especially, the properties of and measuring technique with suitable tracers are considered (e.g. T, Na-24, Cr-51, Co-58, Co-60, Br-82, Tc-99, I-125, I-131, Au-198). (orig./HP) [de

  20. Groundwater flow modelling at the Olkiluoto site, Finland

    International Nuclear Information System (INIS)

    Loefman, J.

    1996-01-01

    Preliminary site investigations for spent fuel disposal has been carried out at the Olkiluoto site, Finland. During the investigations high salt concentrations were measured in the groundwater samples deep in the bedrock. In this study, the groundwater flow is analyzed at Olkiluoto taking into account the effects of salinity. The transient simulations are performed by solving coupled and non-linear partial differential equations describing the flow and solute transport. A site-specific simulation model for flow and transport is developed on the basis of the field investigations. The simulations are carried out for a period that started when the highest hills at Olkiluoto rose above sea level. The simulation period continues until the present day. The results of the coupled simulations were strongly dependent on the poorly known initial salinity distribution in the solution domain. The DP approximation together with the EC approximation proved to be a useful complementary approach when simulating solute transport in a fractured rock mass. The simulations also confirm the assumption that the realistic simulation of groundwater flow at Olkiluoto requires taking into account the effects of salinity

  1. Climate proxy data as groundwater tracers in regional flow systems

    Science.gov (United States)

    Clark, J. F.; Morrissey, S. K.; Stute, M.

    2008-05-01

    The isotopic and chemical signatures of groundwater reflect local climate conditions. By systematically analyzing groundwater and determining their hydrologic setting, records of past climates can be constructed. Because of their chemistries and relatively uncomplicated source functions, dissolved noble gases have yielded reliable records of continental temperatures for the last 30,000 to 50,000 years. Variations in the stable isotope compositions of groundwater due to long term climate changes have also been documented over these time scales. Because glacial - interglacial climate changes are relatively well known, these climate proxies can be used as "stratigraphic" markers within flow systems and used to distinguish groundwaters that have recharged during the Holocene from those recharged during the last glacial period, important time scales for distinguishing regional and local flow systems in many aquifers. In southern Georgia, the climate proxy tracers were able to identify leakage from surface aquifers into the Upper Floridan aquifer in areas previously thought to be confined. In south Florida, the transition between Holocene and glacial signatures in the Upper Floridan aquifer occurs mid-way between the recharge area and Lake Okeechobee. Down gradient of the lake, the proxies are uniform, indicating recharge during the last glacial period. Furthermore, there is no evidence for leakage from the shallow aquifers into the Upper Floridan. In the Lower Floridan, the climate proxies indicate that the saline water entered the aquifer after sea level rose to its present level.

  2. Equilibrium concentration of radionuclides in cement/groundwater/carbon steel system

    International Nuclear Information System (INIS)

    Keum, D. K.; Cho, W. J.; Hahn, P. S.

    1997-01-01

    Equilibrium concentration of major elements in an underground repository with a capacity of 100,000 drums have been simulated using the geochemical computer code (EQMOD). The simulation has been carried out at the conditions of pH 12 to 13.5, and Eh 520 and -520 mV. Solubilities of magnesium and calcium decrease with the increase of pH. The solubility of iron increases with pH at Eh -520 mV of reducing environment, while it almost entirely exists as the precipitate of Fe(OH) 3 (s) at Eh 520 mV of oxidizing environment. All of cobalt and nickel are predicted to be dissolved in the liquid phase regardless of pH since the solubility limit is greater than the total concentration. In the case of cesium and strontium, all forms of both ions are present in the liquid phase because they have negligible sorption capacity on cement and large solubility under disposal atmosphere. And thus the total concentration determines the equilibrium concentration. Adsorbed amounts of iodide and carbonate are dependent on adsorption capacity and adsorption equilibrium constant. Especially, the calcite turns out to be a solubility-limiting phase on the carbonate system. In order to validate the model, the equilibrium concentrations measured for a number of systems which consist of iron, cement, synthetic groundwater and radionuclides are compared with those predicted by the model. The concentrations between the model and the experiment of nonadsorptive elements - cesium, strontium, cobalt, nickel and iron, are well agreed. It indicates that the assumptions and the thermodynamic data in this work are valid. Using the adsorption equilibrium constant as a free parameter, the experimental data of iodide and carbonate have been fitted to the model. The model is in a good agreement with the experimental data of the iodide system. (author)

  3. Application of mathematical model for simulation of groundwater flow

    International Nuclear Information System (INIS)

    Carvalho Filho, Carlos Alberto de; Branco, Otavio Eurico de Aquino; Loureiro, Celso de Oliveira

    2000-01-01

    The main purpose of the present research work is the groundwater flow characterization of the aquifer system of the Engenho Nogueira Creek watershed basin, particularly within the limits of the Pampulha Campus of the Federal University of Minas Gerais and nearby. In order to reach the aforementioned goal, a numerical model was implemented for simulation the groundwater flow, using the MODFLOW code. The local hydrogeology consists of a porous granular aquifer placed above and hydraulically connected to a fractured aquifer, constituting a unique aquifer system, mixed and phreatic type, heterogeneous and anisotropic. The local hydrogeological system is strongly influenced by a complex drain system and by the Engenho Nogueira Creek. After calibration, it was possible to predict the average phreatic depth measured in the observation wells for the period in study with a standard deviation of 1.65 m and a correlation coefficient of 0.94. (author)

  4. Geochemical and Isotopic Interpretations of Groundwater Flow in the Oasis Valley Flow System, Southern Nevada

    International Nuclear Information System (INIS)

    Thomas, J.M.; Benedict, F.C. Jr.; Rose, T.P.; Hershey, R.L.; Paces, J.B.; Peterman, Z.E.; Farnham, I.M.; Johannesson, K.H.; Singh, A.K.; Stetzenbach, K.J.; Hudson, G.B.; Kenneally, J.M.; Eaton, G.F.; Smith, D.K.

    2003-01-01

    This report summarizes the findings of a geochemical investigation of the Pahute Mesa-Oasis Valley groundwater flow system in southwestern Nevada. It is intended to provide geochemical data and interpretations in support of flow and contaminant transport modeling for the Western and Central Pahute Mesa Corrective Action Units

  5. The flow of radionuclides through the Canadian archipelago

    International Nuclear Information System (INIS)

    Ellis, K.; Smith, J.N.

    1999-01-01

    The transport of contaminants to the Canadian Arctic by air and in water and their concentration through the marine food web has lead to enhanced levels of contaminants in several foods of Canadian northern inhabitants. Artificial radionuclides in the marine water can be used to determine water circulation and to trace contaminant transport through the Canadian Archipelago

  6. Separation of base flow from streamflow using groundwater levels - illustrated for the Pang catchment (UK)

    NARCIS (Netherlands)

    Peters, E.; Lanen, van H.A.J.

    2005-01-01

    A new filter to separate base flow from streamflow has developed that uses observed groundwater levels. To relate the base flow to the observed groundwater levels, a non-linear relation was used. This relation is suitable for unconfined aquifers with deep groundwater levels that do not respond to

  7. Identification and characterization of potential discharge areas for radionuclide transport by groundwater from a nuclear waste repository in Sweden.

    Science.gov (United States)

    Berglund, Sten; Bosson, Emma; Selroos, Jan-Olof; Sassner, Mona

    2013-05-01

    This paper describes solute transport modeling carried out as a part of an assessment of the long-term radiological safety of a planned deep rock repository for spent nuclear fuel in Forsmark, Sweden. Specifically, it presents transport modeling performed to locate and describe discharge areas for groundwater potentially carrying radionuclides from the repository to the surface where man and the environment could be affected by the contamination. The modeling results show that topography to large extent determines the discharge locations. Present and future lake and wetland objects are central for the radionuclide transport and dose calculations in the safety assessment. Results of detailed transport modeling focusing on the regolith and the upper part of the rock indicate that the identification of discharge areas and objects considered in the safety assessment is robust in the sense that it does not change when a more detailed model representation is used.

  8. Radionuclide and dopplergraphic assessment of portal hepatic blood flow in opisthorchiasis

    International Nuclear Information System (INIS)

    Borodulin, V.G.; Ermolitskij, N.M.; Zavadovskaya, V.D.; Prosekina, N.M.; Borodulin, Yu.V.

    1996-01-01

    Dynamic studies of the portal blood flow were carried out in 88 patients using colloid radionuclide gold-198 and Tc-99m-phytate and in 84 patients by dopplerography. Radionuclide studies showed that both radiopharmaceutical adequately reflected the portal blood flow in the liver. Portal blood flow values obtained by the duplex echographic method were 0.7 times lower than these estimated by radionuclide indirect angiography. The authors come to a conclusions that the share of the liver in colloid capture should be taken into consideration for the correct estimation of the level of portal hepatic hemodynamics. Portal hepatic blood flow was found markedly reduced in patients with chronic opisthorchiasis in comparison with normal controls, this difference being more expressed in male patients [ru

  9. Unsaturated Groundwater Flow Beneath Upper Mortandad Canyon, Los Alamos, New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Dander, David Carl [Univ. of Arizona, Tucson, AZ (United States)

    1998-10-15

    Mortandad Canyon is a discharge site for treated industrial effluents containing radionuclides and other chemicals at Los Alamos National Laboratory, New Mexico. This study was conducted to develop an understanding of the unsaturated hydrologic behavior below the canyon floor. The main goal of this study was to evaluate the hypothetical performance of the vadose zone above the water table. Numerical simulations of unsaturated groundwater flow at the site were conducted using the Finite Element Heat and Mass Transfer (FEHM) code. A two-dimensional cross-section along the canyon's axis was used to model flow between an alluvial groundwater system and the regional aquifer approximately 300 m below. Using recharge estimated from a water budget developed in 1967, the simulations showed waters from the perched water table reaching the regional aquifer in 13.8 years, much faster than previously thought. Additionally, simulations indicate that saturation is occurring in the Guaje pumice bed an d that the Tshirege Unit 1B is near saturation. Lithologic boundaries between the eight materials play an important role in flow and solute transport within the system. Horizontal flow is shown to occur in three thin zones above capillary barriers; however, vertical flow dominates the system. Other simulations were conducted to examine the effects of changing system parameters such as varying recharge inputs, varying the distribution of recharge, and bypassing fast-path fractured basalt of uncertain extent and properties. System sensitivity was also explored by changing model parameters with respect to size and types of grids and domains, and the presence of dipping stratigraphy.

  10. Coupled heat and groundwater flow in porous rock

    International Nuclear Information System (INIS)

    Rae, J.; Robinson, P.C.; Wickens, L.M.

    1983-01-01

    There are a number of technical areas where coupled heat and flow problems occur for water in porous rock. The area of most interest to the authors has been the possible disposal underground of high-level radioactive waste. High-level waste can emit enough heat to drive significant flows by buoyancy effects and groundwater flow is expected to be the chief transport process for solute leached from such a repository. The possible disposal of radioactive waste under the seabed raises many similar questions and needs similar techniques to find answers. Other areas where related questions arise are the storage and retrieval of hot water in underground reservoirs, the attempts to extract useful geothermal energy by pumping water into fracture systems in hot rock and in certain thermal techniques for persuading oil to flow in tight reservoirs. The authors address questions in a rather general way and give examples which lie more in the area of waste disposal

  11. New approach for simulating groundwater flow in discrete fracture network

    Science.gov (United States)

    Fang, H.; Zhu, J.

    2017-12-01

    In this study, we develop a new approach to calculate groundwater flowrate and hydraulic head distribution in two-dimensional discrete fracture network (DFN) where both laminar and turbulent flows co-exist in individual fractures. The cubic law is used to calculate hydraulic head distribution and flow behaviors in fractures where flow is laminar, while the Forchheimer's law is used to quantify turbulent flow behaviors. Reynolds number is used to distinguish flow characteristics in individual fractures. The combination of linear and non-linear equations is solved iteratively to determine flowrates in all fractures and hydraulic heads at all intersections. We examine potential errors in both flowrate and hydraulic head from the approach of uniform flow assumption. Applying the cubic law in all fractures regardless of actual flow conditions overestimates the flowrate when turbulent flow may exist while applying the Forchheimer's law indiscriminately underestimate the flowrate when laminar flows exist in the network. The contrast of apertures of large and small fractures in the DFN has significant impact on the potential errors of using only the cubic law or the Forchheimer's law. Both the cubic law and Forchheimer's law simulate similar hydraulic head distributions as the main difference between these two approaches lies in predicting different flowrates. Fracture irregularity does not significantly affect the potential errors from using only the cubic law or the Forchheimer's law if network configuration remains similar. Relative density of fractures does not significantly affect the relative performance of the cubic law and Forchheimer's law.

  12. Regional-to-site scale groundwater flow in Romuvaara

    Energy Technology Data Exchange (ETDEWEB)

    Kattilakoski, E.; Koskinen, L. [VTT Energy, Espoo (Finland)

    1999-04-01

    The work describing numerical groundwater flow modelling at the Romuvaara site serves as a background report for the safety assessment TILA-99. The site scale can roughly be taken as the scale of detailed borehole investigations, which have probed the bedrock of Romuvaara over about 2 km{sup 2} large and 1 km deep volume. The site model in this work covers an area of about 12 km{sup 2}. The depth of the model is 2200 m. The site scale flow modelling produced characteristics of the deep groundwater flow and evaluated the impact of a spent fuel repository on the natural groundwater flow conditions. It treated the hydraulic gradient in the intact rock between the repository and the fracture zone nearest to it (about 50 m off) for the block scale model, which describes the groundwater flow on the repository scale. The result quantities were the hydraulic head h (as the base quantity) and its gradient in selected cross sections and fracture zones, the flow rates around the repository, flow paths and discharge areas of the water from the repository. Two repository layouts were discussed. The numerical simulations were performed with the FEFTRA code based on the porous medium concept and the finite element method. The regional model with a no-flow boundary condition at the bottom and on the lateral edges was firstly used to confirm the hydraulic head boundary condition on the lateral edges of an interior site model (having a no-flow boundary condition at the bottom). The groundwater table was used as the hydraulic head boundary condition at the surface of each model. Both the conductivity of the bedrock (modeled with three-dimensional elements) and the transmissivities of the fracture zones (described with two-dimensional elements in the three-dimensional mesh) decreased as a function of the depth. All the results were derived from the site model. The range of variation of the hydraulic gradient immediately outside the repository was studied in the direction of the flow

  13. Numerical simulation of groundwater flow in the Columbia Plateau Regional Aquifer System, Idaho, Oregon, and Washington

    Science.gov (United States)

    Ely, D. Matthew; Burns, Erick R.; Morgan, David S.; Vaccaro, John J.

    2014-01-01

    A three-dimensional numerical model of groundwater flow was constructed for the Columbia Plateau Regional Aquifer System (CPRAS), Idaho, Oregon, and Washington, to evaluate and test the conceptual model of the system and to evaluate groundwater availability. The model described in this report can be used as a tool by water-resource managers and other stakeholders to quantitatively evaluate proposed alternative management strategies and assess the long‑term availability of groundwater. The numerical simulation of groundwater flow in the CPRAS was completed with support from the Groundwater Resources Program of the U.S. Geological Survey Office of Groundwater.

  14. The treatment of water-conducting features in groundwater flow and transport modelling of the Borrowdale Volcanic Group in Nirex 97

    International Nuclear Information System (INIS)

    Jackson, C.P.; Norris, S.; Todman, S.J.; Watson, S.P.

    1999-01-01

    In the Nirex 97 assessment of the post-closure performance of a repository at Sellafield, the potential repository host rock was the Borrowdale Volcanic Group (BVG). The treatment of water-conducting features in groundwater flow and transport modelling of the BVG is discussed. Groundwater flow in the BVG is predominantly through a subset of the total set of discontinuities - the Flowing Features (FFs). FFs can be identified in core samples by the presence of recent calcite. In boreholes, the FFs are clustered, and the clustering appears to be significant hydro-geologically. However, there is uncertainty about the connectivity of the clusters. A range of models is possible, from the case of isolated clusters to the case where the clusters form a well-connected network. The radiological risk from the repository was determined from radionuclide transport calculations based on the groundwater flow fields obtained from the regional-scale flow calculations. For rocks, such as the BVG, in which groundwater flows predominantly through discontinuities, diffusion into immobile water int the rock matrix between the discontinuities was modelled. Data from the site characterization and research programmes could be used to develop and parameterize groundwater flow and transport models for use in repository performance assessments. (author)

  15. Radioactive Seepage through Groundwater Flow from the Uranium Mines, Namibia

    Directory of Open Access Journals (Sweden)

    Tamiru Abiye

    2017-02-01

    Full Text Available The study focused on the seepage of uranium from unlined tailing dams into the alluvial aquifer in the Gawib River floodplain in Namibia where the region solely relies on groundwater for its economic activities as a result of arid climatic condition. The study reviewed previous works besides water sample collection and analyses for major ions, metals and environmental isotopes in addition to field tests on physico-chemical parameters (pH, Electrical Conductivity, Redox and T. Estimation of seepage velocity (true velocity of groundwater flow has been conducted in order to understand the extent of radioactive plume transport. The hydrochemistry, stable isotopes and tritium results show that there is uranium contamination from the unlined uranium tailings in the Gawib shallow aquifer system which suggests high permeability of the alluvial aquifer facilitating groundwater flow in the arid region. The radioactive contaminants could spread into the deeper aquifer system through the major structures such as joints and faults. The contamination plume could also spread downstream into the Swakop River unless serious interventions are employed. There is also a very high risk of the plume to reach the Atlantic Ocean through seasonal flash floods that occurs in the area.

  16. Simulation of the regional groundwater-flow system of the Menominee Indian Reservation, Wisconsin

    Science.gov (United States)

    Juckem, Paul F.; Dunning, Charles P.

    2015-01-01

    A regional, two-dimensional, steady-state groundwater-flow model was developed to simulate the groundwater-flow system and groundwater/surface-water interactions within the Menominee Indian Reservation. The model was developed by the U.S. Geological Survey (USGS), in cooperation with the Menominee Indian Tribe of Wisconsin, to contribute to the fundamental understanding of the region’s hydrogeology. The objectives of the regional model were to improve understanding of the groundwater-flow system, including groundwater/surface-water interactions, and to develop a tool suitable for evaluating the effects of potential regional water-management programs. The computer code GFLOW was used because of the ease with which the model can simulate groundwater/surface-water interactions, provide a framework for simulating regional groundwater-flow systems, and be refined in a stepwise fashion to incorporate new data and simulate groundwater-flow patterns at multiple scales. Simulations made with the regional model reproduce groundwater levels and stream base flows representative of recent conditions (1970–2013) and illustrate groundwater-flow patterns with maps of (1) the simulated water table and groundwater-flow directions, (2) probabilistic areas contributing recharge to high-capacity pumped wells, and (3) estimation of the extent of infiltrated wastewater from treatment lagoons.

  17. From groundwater baselines to numerical groundwater flow modelling for the Milan metropolitan area

    Science.gov (United States)

    Crosta, Giovanni B.; Frattini, Paolo; Peretti, Lidia; Villa, Federica; Gorla, Maurizio

    2015-04-01

    allow for the groundwater flow and transport modeling at the large scale and could be successively linked to some more site-specific transport multi-reactive models focused on the modeling of some specific contaminants.

  18. PHAST Version 2-A Program for Simulating Groundwater Flow, Solute Transport, and Multicomponent Geochemical Reactions

    Science.gov (United States)

    Parkhurst, David L.; Kipp, Kenneth L.; Charlton, Scott R.

    2010-01-01

    The computer program PHAST (PHREEQC And HST3D) simulates multicomponent, reactive solute transport in three-dimensional saturated groundwater flow systems. PHAST is a versatile groundwater flow and solute-transport simulator with capabilities to model a wide range of equilibrium and kinetic geochemical reactions. The flow and transport calculations are based on a modified version of HST3D that is restricted to constant fluid density and constant temperature. The geochemical reactions are simulated with the geochemical model PHREEQC, which is embedded in PHAST. Major enhancements in PHAST Version 2 allow spatial data to be defined in a combination of map and grid coordinate systems, independent of a specific model grid (without node-by-node input). At run time, aquifer properties are interpolated from the spatial data to the model grid; regridding requires only redefinition of the grid without modification of the spatial data. PHAST is applicable to the study of natural and contaminated groundwater systems at a variety of scales ranging from laboratory experiments to local and regional field scales. PHAST can be used in studies of migration of nutrients, inorganic and organic contaminants, and radionuclides; in projects such as aquifer storage and recovery or engineered remediation; and in investigations of the natural rock/water interactions in aquifers. PHAST is not appropriate for unsaturated-zone flow, multiphase flow, or density-dependent flow. A variety of boundary conditions are available in PHAST to simulate flow and transport, including specified-head, flux (specified-flux), and leaky (head-dependent) conditions, as well as the special cases of rivers, drains, and wells. Chemical reactions in PHAST include (1) homogeneous equilibria using an ion-association or Pitzer specific interaction thermodynamic model; (2) heterogeneous equilibria between the aqueous solution and minerals, ion exchange sites, surface complexation sites, solid solutions, and gases; and

  19. Disequilibrium study of natural radionuclides of uranium and thorium series in cores and briny groundwaters from Palo Duro Basin, Texas

    International Nuclear Information System (INIS)

    Laul, J.C.; Smith, M.R.

    1988-05-01

    The concentrations of natural radionuclides of the 238 U and /232/Th series are reported in several cores and in ten deep and five shallow briny groundwaters from various formations in the Palo Duro Basin. The formations include Granite Wash, Pennsylvanian Granite Wash, Wolfcamp Carbonate, Pennsylvanian Carbonate, Seven River, Queen Grayburg, San Andres, Yates and Salado. The natural radionuclide data in cores suggest that the radionuclides have not migrated or been leached for at least a period of about 1 million years. Relative to the U and Th concentrations in cores, the brines are depleted by a factor of 10 4 to 10 5 , indicating extremely low solubility of U and Th in brines. The natural radionuclide data in brines suggest that radium is not sorbed significantly and thus not retarded in nine deep brines. Radium is somewhat sorbed in one deep brine of Wolfcamp Carbonate and significantly sorbed in shallow brines. Relative to radium, the U, Th, Pb, Bi, and Po radionuclides are highly retarded by sorption. The retardation factors for 228 Th range from 10 2 to 10 3 , whereas those for 230 Th and 234 U range from 10 3 to 10 5 , depending on the formation. The 234 U/ 238 U ratios in these brines are constant at about 1.5. The magnitude of the 234 U/ 230 Th ratio appears to reflect the degree of redox state of the aquifer's environment. The 234 U/ 230 Th ratio in nine deep brines is about unity, suggesting that U, like Th +4 , is in the +4 state, which in turn suggests a reduced environment. 49 refs., 23 figs., 18 tabs

  20. The 2016 groundwater flow model for Dane County, Wisconsin

    Science.gov (United States)

    Parsen, Michael J.; Bradbury, Kenneth R.; Hunt, Randall J.; Feinstein, Daniel T.

    2016-01-01

    A new groundwater flow model for Dane County, Wisconsin, replaces an earlier model developed in the 1990s by the Wisconsin Geological and Natural History Survey (WGNHS) and the U.S. Geological Survey (USGS). This modeling study was conducted cooperatively by the WGNHS and the USGS with funding from the Capital Area Regional Planning Commission (CARPC). Although the overall conceptual model of the groundwater system remains largely unchanged, the incorporation of newly acquired high-quality datasets, recent research findings, and improved modeling and calibration techniques have led to the development of a more detailed and sophisticated model representation of the groundwater system. The new model is three-dimensional and transient, and conceptualizes the county’s hydrogeology as a 12-layer system including all major unlithified and bedrock hydrostratigraphic units and two high-conductivity horizontal fracture zones. Beginning from the surface down, the model represents the unlithified deposits as two distinct model layers (1 and 2). A single layer (3) simulates the Ordovician sandstone and dolomite of the Sinnipee, Ancell, and Prairie du Chien Groups. Sandstone of the Jordan Formation (layer 4) and silty dolostone of the St. Lawrence Formation (layer 5) each comprise separate model layers. The underlying glauconitic sandstone of the Tunnel City Group makes up three distinct layers: an upper aquifer (layer 6), a fracture feature (layer 7), and a lower aquifer (layer 8). The fracture layer represents a network of horizontal bedding-plane fractures that serve as a preferential pathway for groundwater flow. The model simulates the sandstone of the Wonewoc Formation as an upper aquifer (layer 9) with a bedding-plane fracture feature (layer 10) at its base. The Eau Claire aquitard (layer 11) includes shale beds within the upper portion of the Eau Claire Formation. This layer, along with overlying bedrock units, is mostly absent in the preglacially eroded valleys along

  1. Groundwater flow modelling of the excavation and operational phases - Laxemar

    Energy Technology Data Exchange (ETDEWEB)

    Svensson, Urban (Computer-aided Fluid Engineering AB, Lyckeby (Sweden)); Rhen, Ingvar (SWECO Environment AB, Falun (Sweden))

    2010-12-15

    As a part of the license application for a final repository for spent nuclear fuel at Forsmark, the Swedish Nuclear Fuel and Waste Management Company (SKB) has undertaken a series of groundwater flow modelling studies. These represent time periods with different hydraulic conditions and the simulations carried out contribute to the overall evaluation of the repository design and long-term radiological safety. The modelling study reported here presents calculated inflow rates, drawdown of the groundwater table and upconing of deep saline water for different levels of grouting efficiency during the excavation and operational phases of a final repository at Laxemar. The inflow calculations were accompanied by a sensitivity study, which among other matters handled the impact of different deposition hole rejection criteria. The report also presents tentative modelling results for the duration of the saturation phase, which starts once the used parts of the repository are being backfilled

  2. A correction on coastal heads for groundwater flow models.

    Science.gov (United States)

    Lu, Chunhui; Werner, Adrian D; Simmons, Craig T; Luo, Jian

    2015-01-01

    We introduce a simple correction to coastal heads for constant-density groundwater flow models that contain a coastal boundary, based on previous analytical solutions for interface flow. The results demonstrate that accurate discharge to the sea in confined aquifers can be obtained by direct application of Darcy's law (for constant-density flow) if the coastal heads are corrected to ((α + 1)/α)hs  - B/2α, in which hs is the mean sea level above the aquifer base, B is the aquifer thickness, and α is the density factor. For unconfined aquifers, the coastal head should be assigned the value hs1+α/α. The accuracy of using these corrections is demonstrated by consistency between constant-density Darcy's solution and variable-density flow numerical simulations. The errors introduced by adopting two previous approaches (i.e., no correction and using the equivalent fresh water head at the middle position of the aquifer to represent the hydraulic head at the coastal boundary) are evaluated. Sensitivity analysis shows that errors in discharge to the sea could be larger than 100% for typical coastal aquifer parameter ranges. The location of observation wells relative to the toe is a key factor controlling the estimation error, as it determines the relative aquifer length of constant-density flow relative to variable-density flow. The coastal head correction method introduced in this study facilitates the rapid and accurate estimation of the fresh water flux from a given hydraulic head measurement and allows for an improved representation of the coastal boundary condition in regional constant-density groundwater flow models. © 2014, National Ground Water Association.

  3. Modelling of Radionuclide Transport by Groundwater Motion in Fractured Bedrock for Performance Assessment Purposes

    International Nuclear Information System (INIS)

    Woerman, Anders; Shulan Xu

    2003-10-01

    Field data of physical properties in heterogeneous crystalline bedrock, like fracture zones, fracture connectivity, matrix porosity and fracture aperture, is associated with uncertainty that can have a significant impact on the analysis of solute transport in fractured rock. The purpose of this study is to develop a performance assessment (PA) model for analyses of radionuclide transport in the geosphere, in which the model takes into account both the effect of heterogeneities of hydrological and geochemical rock properties. By using a travel time description of radionuclide transport in rock fractures, we decompose the transport problem into a one-dimensional mass transfer problem along a distribution of transport pathways and a multi-dimensional flow problem in the fractured bedrock. The hydraulic/flow problem is solved based on a statistical discrete-fracture model (DFM) that represents the network of fractures around the repository and in the surrounding geosphere. A Monte Carlo technique reflects the fact that the representation of the fracture network is uncertain. If the flow residence time PDF exhibits multiple peaks or in another way shows a more erratic hydraulic response on the network scale, the three-dimensional travel time approach is superior to a one-dimensional transport modeling. Examples taken from SITE 94, a study performed by the Swedish Nuclear Power Inspectorate, showed that such cases can be found in safety assessments based on site data. The solute transport is formulated based on partial, differential equations and perturbations (random spatial variability in bedrock properties) are introduced in the coefficients to reflect an uncertainty of the exact appearance of the bedrock associated with the discrete data collection. The combined approach for water flow and solute transport, thereby, recognises an uncertainty in our knowledge in both 1) bedrock properties along individual pathways and 2) the distribution of pathways. Solutions to the

  4. Variable thickness transient ground-water flow model. Volume 3. Program listings

    International Nuclear Information System (INIS)

    Reisenauer, A.E.

    1979-12-01

    The Assessment of Effectiveness of Geologic Isolation Systems (AEGIS) Program is developing and applying the methodology for assessing the far-field, long-term post-closure safety of deep geologic nuclear waste repositories. AEGIS is being performed by Pacific Northwest Laboratory (PNL) under contract with the Office of Nuclear Waste Isolation (OWNI) for the Department of Energy (DOE). One task within AEGIS is the development of methodology for analysis of the consequences (water pathway) from loss of repository containment as defined by various release scenarios. Analysis of the long-term, far-field consequences of release scenarios requires the application of numerical codes which simulate the hydrologic systems, model the transport of released radionuclides through the hydrologic systems to the biosphere, and, where applicable, assess the radiological dose to humans. Hydrologic and transport models are available at several levels of complexity or sophistication. Model selection and use are determined by the quantity and quality of input data. Model development under AEGIS and related programs provides three levels of hydrologic models, two levels of transport models, and one level of dose models (with several separate models). This is the third of 3 volumes of the description of the VTT (Variable Thickness Transient) Groundwater Hydrologic Model - second level (intermediate complexity) two-dimensional saturated groundwater flow

  5. Composite use of numerical groundwater flow modeling and geoinformatics techniques for monitoring Indus Basin aquifer, Pakistan.

    Science.gov (United States)

    Ahmad, Zulfiqar; Ashraf, Arshad; Fryar, Alan; Akhter, Gulraiz

    2011-02-01

    The integration of the Geographic Information System (GIS) with groundwater modeling and satellite remote sensing capabilities has provided an efficient way of analyzing and monitoring groundwater behavior and its associated land conditions. A 3-dimensional finite element model (Feflow) has been used for regional groundwater flow modeling of Upper Chaj Doab in Indus Basin, Pakistan. The approach of using GIS techniques that partially fulfill the data requirements and define the parameters of existing hydrologic models was adopted. The numerical groundwater flow model is developed to configure the groundwater equipotential surface, hydraulic head gradient, and estimation of the groundwater budget of the aquifer. GIS is used for spatial database development, integration with a remote sensing, and numerical groundwater flow modeling capabilities. The thematic layers of soils, land use, hydrology, infrastructure, and climate were developed using GIS. The Arcview GIS software is used as additive tool to develop supportive data for numerical groundwater flow modeling and integration and presentation of image processing and modeling results. The groundwater flow model was calibrated to simulate future changes in piezometric heads from the period 2006 to 2020. Different scenarios were developed to study the impact of extreme climatic conditions (drought/flood) and variable groundwater abstraction on the regional groundwater system. The model results indicated a significant response in watertable due to external influential factors. The developed model provides an effective tool for evaluating better management options for monitoring future groundwater development in the study area.

  6. Impact of radionuclide spatial variability on groundwater quality downstream from a shallow waste burial in the Chernobyl Exclusion Zone

    Science.gov (United States)

    Nguyen, H. L.; de Fouquet, C.; Courbet, C.; Simonucci, C. A.

    2016-12-01

    The effects of spatial variability of hydraulic parameters and initial groundwater plume localization on the possible extent of groundwater pollution plumes have already been broadly studied. However, only a few studies, such as Kjeldsen et al. (1995), take into account the effect of source term spatial variability. We explore this question with the 90Sr migration modeling from a shallow waste burial located in the Chernobyl Exclusion Zone to the underlying sand aquifer. Our work is based upon groundwater sampled once or twice a year since 1995 until 2015 from about 60 piezometers and more than 3,000 137Cs soil activity measurements. These measurements were taken in 1999 from one of the trenches dug after the explosion of the Chernobyl nuclear power plant, the so-called "T22 Trench", where radioactive waste was buried in 1987. The geostatistical analysis of 137Cs activity data in soils from Bugai et al. (2005) is first reconsidered to delimit the trench borders using georadar data as a covariable and to perform geostatistical simulations in order to evaluate the uncertainties of this inventory. 90Sr activity in soils is derived from 137Cs/154Eu and 90Sr/154Eu activity ratios in Chernobyl hot fuel particles (Bugai et al., 2003). Meanwhile, a coupled 1D non saturated/3D saturated transient transport model is constructed under the MELODIE software (IRSN, 2009). The previous 90Sr transport model developed by Bugai et al. (2012) did not take into account the effect of water table fluctuations highlighted by Van Meir et al. (2007) which may cause some discrepancies between model predictions and field observations. They are thus reproduced on a 1D vertical non saturated model. The equiprobable radionuclide localization maps produced by the geostatistical simulations are selected to illustrate different heterogeneities in the radionuclide inventory and are implemented in the 1D model. The obtained activity fluxes from all the 1D vertical models are then injected in a 3D

  7. Hanford groundwater scenario studies

    International Nuclear Information System (INIS)

    Arnett, R.C.; Gephart, R.E.; Deju, R.A.; Cole, C.R.; Ahlstrom, S.W.

    1977-05-01

    This report documents the results of two Hanford groundwater scenario studies. The first study examines the hydrologic impact of increased groundwater recharge resulting from agricultural development in the Cold Creek Valley located west of the Hanford Reservation. The second study involves recovering liquid radioactive waste which has leaked into the groundwater flow system from a hypothetical buried tank containing high-level radioactive waste. The predictive and control capacity of the onsite Hanford modeling technology is used to evaluate both scenarios. The results of the first study indicate that Cold Creek Valley irrigationis unlikely to cause significant changes in the water table underlying the high-level waste areas or in the movement of radionuclides already in the groundwater. The hypothetical tank leak study showed that an active response (in this case waste recovery) can be modeled and is a possible alternative to passive monitoring of radionuclide movement in the unlikely event that high-level waste is introduced into the groundwater

  8. Laboratory studies of radionuclide distributions between selected groundwaters and geologic media. Progress report, October 1, 1979-September 30, 1980

    International Nuclear Information System (INIS)

    Daniels, W.R.

    1981-01-01

    During FY-1980, Los Alamos Scientific Laboratory contributions to the Waste/Rock Interactions Technology program were primarily in the areas of migration-rate studies using crushed rock, whole core, and fractured core columns; parametric studies of variables which may influence radionuclide sorption-desorption behavior; and initial studies of actinide chemistry in near-neutral solutions and Eh control. Batch experiments in both air and a controlled atmosphere (nitrogen, less than or equal to 0.2 ppM oxygen, less than or equal to 20 ppM carbon dioxide) for the sorption of several radionuclides on granite and argillite were completed. These data also provided informaton on the effects of other parameters, such as particle size and contact time. All nine elements studied had different sorption ratios for argillite when measured under the controlled atmosphere than when measured in air, except possibly for americium where any effect was smaller than the standard deviations. As expected, strontium, cesium, and barium are least affected by the presence or absence of oxygen and carbon dioxide. Columns of crushed rock and solid and cracked cores were used to study the migration of radionuclides through such materials. In general, sorption ratios measured by batch techniques are 2 to 3 times greater than those for columns; however, a wide variation in behavior was observed, depending upon the element and the mineralogy. Work has begun on a system wherein traced groundwater is circulated through a crushed rock column; this should provide a link between the usual, single-pass, crushed rock columns and the batch experiments. Materials characterization has continued, and techniques for the determination of Fe(II) in silicate rocks and groundwater have been made operational. Work on the fundamental solution chemistry of the actinides has been started

  9. Ground-water flow in low permeability environments

    Science.gov (United States)

    Neuzil, Christopher E.

    1986-01-01

    Certain geologic media are known to have small permeability; subsurface environments composed of these media and lacking well developed secondary permeability have groundwater flow sytems with many distinctive characteristics. Moreover, groundwater flow in these environments appears to influence the evolution of certain hydrologic, geologic, and geochemical systems, may affect the accumulation of pertroleum and ores, and probably has a role in the structural evolution of parts of the crust. Such environments are also important in the context of waste disposal. This review attempts to synthesize the diverse contributions of various disciplines to the problem of flow in low-permeability environments. Problems hindering analysis are enumerated together with suggested approaches to overcoming them. A common thread running through the discussion is the significance of size- and time-scale limitations of the ability to directly observe flow behavior and make measurements of parameters. These limitations have resulted in rather distinct small- and large-scale approaches to the problem. The first part of the review considers experimental investigations of low-permeability flow, including in situ testing; these are generally conducted on temporal and spatial scales which are relatively small compared with those of interest. Results from this work have provided increasingly detailed information about many aspects of the flow but leave certain questions unanswered. Recent advances in laboratory and in situ testing techniques have permitted measurements of permeability and storage properties in progressively “tighter” media and investigation of transient flow under these conditions. However, very large hydraulic gradients are still required for the tests; an observational gap exists for typical in situ gradients. The applicability of Darcy's law in this range is therefore untested, although claims of observed non-Darcian behavior appear flawed. Two important nonhydraulic

  10. Regional-to-site scale groundwater flow in Kivetty

    Energy Technology Data Exchange (ETDEWEB)

    Kattilakoski, E. [VTT Energy, Espoo (Finland); Meszaros, F. [The Relief Laboratory, Harskut (Hungary)

    1999-04-01

    The work describing numerical groundwater flow modelling at the Kivetty site serves as a background report for the safety assessment TILA-99. The site scale can roughly be taken as the scale of detailed borehole investigations, which have probed the bedrock of Kivetty over about 3 km{sup 2} large and 1 km deep volume. The site model in this work covers an area of about 16 km{sup 2}. The depth of the model is 2000 m. The site scale flow modelling produced characteristics of the deep groundwater flow both under the natural conditions and in the case of a spent fuel repository. The hydraulic gradient in the intact rock between the repository and the fracture zone nearest to it (about 50 m off) was assessed for the block scale model. The result quantities were the hydraulic head h (as the base quantity) and its gradient in selected cross sections and fracture zones, the flow rates around the repository, flow paths and discharge areas of the water from the repository. Two repository layouts were discussed. The numerical simulations were performed with the FEFTRA code based on the porous medium concept and the finite element method. The regional model with a no-flow boundary condition at the bottom and on the lateral edges was firstly used to confirm the hydraulic head boundary condition on the lateral edges of an interior site model (having a no-flow boundary condition at the bottom). The groundwater table was used as the hydraulic head boundary condition at the surface of each model. Both the conductivity of the bedrock (modeled with three-dimensional elements) and the transmissivities of the fracture zones (described with two-dimensional elements in the three-dimensional mesh) decreased as a function of the depth. All the results were derived from the site model. With the exception of the western part of Repository A the outlined repositories are located underneath Kumpuvuori, where the flow has a significant subvertical component. The horizontal component of the deep

  11. Regional-to-site scale groundwater flow in Kivetty

    International Nuclear Information System (INIS)

    Kattilakoski, E.; Meszaros, F.

    1999-04-01

    The work describing numerical groundwater flow modelling at the Kivetty site serves as a background report for the safety assessment TILA-99. The site scale can roughly be taken as the scale of detailed borehole investigations, which have probed the bedrock of Kivetty over about 3 km 2 large and 1 km deep volume. The site model in this work covers an area of about 16 km 2 . The depth of the model is 2000 m. The site scale flow modelling produced characteristics of the deep groundwater flow both under the natural conditions and in the case of a spent fuel repository. The hydraulic gradient in the intact rock between the repository and the fracture zone nearest to it (about 50 m off) was assessed for the block scale model. The result quantities were the hydraulic head h (as the base quantity) and its gradient in selected cross sections and fracture zones, the flow rates around the repository, flow paths and discharge areas of the water from the repository. Two repository layouts were discussed. The numerical simulations were performed with the FEFTRA code based on the porous medium concept and the finite element method. The regional model with a no-flow boundary condition at the bottom and on the lateral edges was firstly used to confirm the hydraulic head boundary condition on the lateral edges of an interior site model (having a no-flow boundary condition at the bottom). The groundwater table was used as the hydraulic head boundary condition at the surface of each model. Both the conductivity of the bedrock (modeled with three-dimensional elements) and the transmissivities of the fracture zones (described with two-dimensional elements in the three-dimensional mesh) decreased as a function of the depth. All the results were derived from the site model. With the exception of the western part of Repository A the outlined repositories are located underneath Kumpuvuori, where the flow has a significant subvertical component. The horizontal component of the deep

  12. The role of regional groundwater flow in the hydrogeology of the Culebra member of the Rustler formation at the Waste Isolation Pilot Plant (WIPP), southeastern New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Corbet, T.F. [Sandia National Lab., Albuquerque, NM (United States); Knupp, P.M. [Ecodynamics Research Associates, Albuquerque, NM (United States)

    1996-12-01

    Numerical simulation has been used to enhance conceptual understanding, of the hydrogeology of the Culebra Dolomite in the context of regional groundwater flow. The hydrogeology is of interest because this unit is a possible pathway for offsite migration of radionuclides from a proposed repository for defense-generated transuranic wastes (the Waste Isolation Pilot Plant). The numerical model used is three-dimensional, extends laterally to topographic features that form the actual boundaries of a regional groundwater system, and uses a free-surface upper boundary condition to simulate the effect of change in the rate of recharge on groundwater flow. Steady-state simulations were performed to examine the sensitivity of simulation results to assumed values for hydraulic conductivity and recharge rate. Transient simulations, covering the time period from 14,000 years in the past to 10,000 years in the future, provided insight into how patterns of groundwater flow respond to changes in climate. Simulation results suggest that rates and directions of Groundwater flow in the Culebra change with time due to interaction between recharge, movement of the water table, and the topography of the land surface. The gentle east-to-west slope of the land surface in the vicinity of the WIPP caused groundwater in the Culebra to flow toward and discharge into Nash Draw, a topographic depression. Modern-day flow directions in the Culebra reflect regional rather than local features of the topography. Changes in Groundwater flow, however, lagged behind changes in the rate of recharge. The present-day position of the water table is still adjusting to the decrease in recharge that ended 8,000 years ago. Contaminants introduced into the Culebra will travel toward the accessible environment along the Culebra rather than by leaking upward or downward into other units. Natural changes in flow over the next 10,000 years will be small and will mainly reflect future short-term wet periods.

  13. The role of regional groundwater flow in the hydrogeology of the Culebra member of the Rustler formation at the Waste Isolation Pilot Plant (WIPP), southeastern New Mexico

    International Nuclear Information System (INIS)

    Corbet, T.F.; Knupp, P.M.

    1996-12-01

    Numerical simulation has been used to enhance conceptual understanding, of the hydrogeology of the Culebra Dolomite in the context of regional groundwater flow. The hydrogeology is of interest because this unit is a possible pathway for offsite migration of radionuclides from a proposed repository for defense-generated transuranic wastes (the Waste Isolation Pilot Plant). The numerical model used is three-dimensional, extends laterally to topographic features that form the actual boundaries of a regional groundwater system, and uses a free-surface upper boundary condition to simulate the effect of change in the rate of recharge on groundwater flow. Steady-state simulations were performed to examine the sensitivity of simulation results to assumed values for hydraulic conductivity and recharge rate. Transient simulations, covering the time period from 14,000 years in the past to 10,000 years in the future, provided insight into how patterns of groundwater flow respond to changes in climate. Simulation results suggest that rates and directions of Groundwater flow in the Culebra change with time due to interaction between recharge, movement of the water table, and the topography of the land surface. The gentle east-to-west slope of the land surface in the vicinity of the WIPP caused groundwater in the Culebra to flow toward and discharge into Nash Draw, a topographic depression. Modern-day flow directions in the Culebra reflect regional rather than local features of the topography. Changes in Groundwater flow, however, lagged behind changes in the rate of recharge. The present-day position of the water table is still adjusting to the decrease in recharge that ended 8,000 years ago. Contaminants introduced into the Culebra will travel toward the accessible environment along the Culebra rather than by leaking upward or downward into other units. Natural changes in flow over the next 10,000 years will be small and will mainly reflect future short-term wet periods

  14. Geochemical effects on the behavior of LLW radionuclides in soil/groundwater environments

    Energy Technology Data Exchange (ETDEWEB)

    Krupka, K.M.; Sterne, R.J. [Pacific Northwest Lab., Richland, WA (United States)

    1995-12-31

    Assessing the migration potential of radionuclides leached from low-level radioactive waste (LLW) and decommissioning sites necessitates information on the effects of sorption and precipitation on the concentrations of dissolved radionuclides. Such an assessment requires that the geochemical processes of aqueous speciation, complexation, oxidation/reduction, and ion exchange be taken into account. The Pacific Northwest National Laboratory (PNNL) is providing technical support to the U.S. Nuclear Regulatory Commission (NRC) for defining the solubility and sorption behavior of radionuclides in soil/ground-water environments associated with engineered cementitious LLW disposal systems and decommissioning sites. Geochemical modeling is being used to predict solubility limits for radionuclides under geochemical conditions associated with these environments. The solubility limits are being used as maximum concentration limits in performance assessment calculations describing the release of contaminants from waste sources. Available data were compiled regarding the sorption potential of radionuclides onto {open_quotes}fresh{close_quotes} cement/concrete where the expected pH of the cement pore waters will equal to or exceed 10. Based on information gleaned from the literature, a list of preferred minimum distribution coefficients (Kd`s) was developed for these radionuclides. The K{sub d} values are specific to the chemical environments associated with the evolution of the compositions of cement/concrete pore waters.

  15. Influence of irrigation on the level, salinity and flow of groundwater at ...

    African Journals Online (AJOL)

    2010-03-31

    Mar 31, 2010 ... piezometers had to be measured, all readings were taken within 3 days. Water levels were measured to estab- lish the effect of rainfall, drainage and irrigation on the groundwater level. These levels were also used to gener- ate groundwater contour maps and to determine the groundwater flow directions.

  16. Evolution of patterns of regional groundwater flow in southeastern New Mexico: Response to post-Pleistocene changes in climate

    International Nuclear Information System (INIS)

    Corbet, T.F.

    1994-01-01

    The Waste Isolation Pilot Plant (WIPP) is a potential repository for transuranic wastes generated by defense programs of the US Department of Energy. The repository site is located 42 km east of the city of Carlsbad, New Mexico in a thick, Permian-age deposit of bedded salt. One consideration in evaluating the performance of the repository is that a future society might inadvertently penetrate the repository with one or more drill holes. Given certain circumstances, these holes could provide a pathway for contaminated brine to move upward into relatively permeable strata located above the bedded salt. There is concern that flowing groundwater could then transport radionuclides laterally to the sub-surface portion of the accessible environment, currently defined by the disposal regulations as the region more than 5 kilometers from the radioactive waste. The simulations presented here are part of a numerical modeling study of the possible impact that a change in climate over the next 10,000 years could have on the pattern of groundwater flow and, consequently, on the migration of radionuclides in strata overlying the repository

  17. Groundwater flow and transport modelling during a glaciation period

    International Nuclear Information System (INIS)

    Jaquet, O.; Siegel, P.

    2003-01-01

    Subsequent to earlier work, SKB has decided to carry out additional hydrogeological modelling studies related to glaciation effects at Aespoe. In particular, sub glacial groundwater flow and the impact assessment on a repository require further studies. As compared to the previous model, the domain geometry and processes involved remain identical, but this time, numerical calculations are performed with the NAMMU package (version 7.1.1) using a finite element formulation. Modified assumptions corresponding to specific boundary conditions are implemented and additional variations of the base case are simulated. The objectives of the study are based on the technical specifications established by SKB. The main objectives may be summarised as follows: Enhancement of the understanding of sub glacial groundwater flow due to basal ice melting. Evaluation of the impact of sub glacial roundwater flow on a repository with respect to its position to the ice margin of the glacier. Assessment of the feasibility of performing large 3D simulations of density-driven flow induced by variable salinity of the groundwater using the NAMMU package. The report begins with an account of the modelling approach applied. Then, the results of the different cases simulated are described, analysed and interpreted in detail. Finally, conclusions are drawn up together with some recommendations related to potential modelling issues for the future. The objectives proposed for the groundwater flow and transport modelling for period of glaciation have been met: The results have shown the importance of the ice tunnels in governing sub glacial groundwater flow due to basal ice melting. The influence of the ice tunnels on the salinity distribution is significant as is their impact on the flow trajectories and, hence, on the resulting travel times. The results of simulation S0 have revealed that no steady-state flow conditions are reached. Due to the chosen salt boundary conditions, salt will continue to

  18. Groundwater flow modelling of periods with temperate climate conditions - Laxemar

    International Nuclear Information System (INIS)

    Joyce, Steven; Simpson, Trevor; Hartley, Lee; Applegate, David; Hoek, Jaap; Jackson, Peter; Roberts, David; Swan, David; Gylling, Bjoern; Marsic, Niko; Rhen, Ingvar

    2010-12-01

    As a part of the license application for a final repository for spent nuclear fuel at Forsmark, the Swedish Nuclear Fuel and Waste Management Company (SKB) has undertaken a series of groundwater flow modelling studies. These represent time periods with different hydraulic conditions and the simulations carried out contribute to the overall evaluation of the repository design and long-term radiological safety. This report concerns the modelling of a repository at the Laxemar-Simpevarp site during temperate climate conditions as a comparison to corresponding modelling carried out for Forsmark /Joyce et al. 2010/. The collation and implementation of onsite hydrogeological and hydrogeochemical data from previous reports are used in the construction of a Hydrogeological base case (reference case conceptualisation) and then an examination of various areas of uncertainty within the current understanding by a series of model variants. The Hydrogeological base case models at three different scales, 'repository', 'site' and 'regional' make use of a discrete fracture network (DFN) and equivalent continuous porous medium (ECPM) models. The use of hydrogeological models allow for the investigation of the groundwater flow from a deep disposal facility to the biosphere and for the calculation of performance measures that will provide an input to the site performance assessment. The focus of the study described in this report has been to perform numerical simulations of the hydrogeological system from post-closure and throughout the temperate period up until the receding shoreline leaves the modelling domain at around 15,000 AD. Besides providing quantitative results for the immediate temperate period following post-closure, these results are also intended to give a qualitative indication of the evolution of the groundwater system during future temperate periods within an ongoing cycle of glacial/inter-glacial events

  19. Groundwater flow modelling of periods with temperate climate conditions - Forsmark

    Energy Technology Data Exchange (ETDEWEB)

    Joyce, Steven; Simpson, Trevor; Hartley, Lee; Applegate, David; Hoek, Jaap; Jackson, Peter; Swan, David (Serco Technical Consulting Services (United Kingdom)); Marsic, Niko (Kemakta Konsult AB (Sweden)); Follin, Sven (SF GeoLogic AB (Sweden))

    2010-11-15

    As a part of the license application for a final repository for spent nuclear fuel at Forsmark, the Swedish Nuclear Fuel and Waste Management Company (SKB) has undertaken a series of groundwater flow modelling studies. These represent time periods with different climate conditions and the simulations carried out contribute to the overall evaluation of the repository design and long-term radiological safety. This report concerns the modelling of a repository at the Forsmark site during temperate conditions; i.e. from post-closure and throughout the temperate period up until the receding shoreline leaves the modelling domain at around 12,000 AD. The collation and implementation of onsite hydrogeological and hydrogeochemical data from previous reports are used in the construction of a hydrogeological base case (reference case conceptualisation) and then in an examination of various areas of uncertainty within the current understanding by a series of model variants. The hydrogeological base case models at three different scales, 'repository', 'site' and 'regional', make use of continuous porous medium (CPM), equivalent continuous porous medium (ECPM) and discrete fracture network (DFN) models. The use of hydrogeological models allow for the investigation of the groundwater flow from a deep disposal facility to the biosphere and for the calculation of performance measures that will provide an input to the site performance assessment. The focus of the study described in this report has been to perform numerical simulations of the hydrogeological system from post-closure and throughout the temperate period. Besides providing quantitative results for the immediate temperate period following post-closure, these results are also intended to give a qualitative indication of the evolution of the groundwater system during future temperate periods within an ongoing cycle of glacial/inter-glacial events

  20. Groundwater flow modelling of periods with temperate climate conditions - Laxemar

    Energy Technology Data Exchange (ETDEWEB)

    Joyce, Steven; Simpson, Trevor; Hartley, Lee; Applegate, David; Hoek, Jaap; Jackson, Peter; Roberts, David; Swan, David (Serco Technical Consulting Services (United Kingdom)); Gylling, Bjoern; Marsic, Niko (Kemakta Konsult AB, Stockholm (Sweden)); Rhen, Ingvar (SWECO Environment AB, Falun (Sweden))

    2010-12-15

    As a part of the license application for a final repository for spent nuclear fuel at Forsmark, the Swedish Nuclear Fuel and Waste Management Company (SKB) has undertaken a series of groundwater flow modelling studies. These represent time periods with different hydraulic conditions and the simulations carried out contribute to the overall evaluation of the repository design and long-term radiological safety. This report concerns the modelling of a repository at the Laxemar-Simpevarp site during temperate climate conditions as a comparison to corresponding modelling carried out for Forsmark /Joyce et al. 2010/. The collation and implementation of onsite hydrogeological and hydrogeochemical data from previous reports are used in the construction of a Hydrogeological base case (reference case conceptualisation) and then an examination of various areas of uncertainty within the current understanding by a series of model variants. The Hydrogeological base case models at three different scales, 'repository', 'site' and 'regional' make use of a discrete fracture network (DFN) and equivalent continuous porous medium (ECPM) models. The use of hydrogeological models allow for the investigation of the groundwater flow from a deep disposal facility to the biosphere and for the calculation of performance measures that will provide an input to the site performance assessment. The focus of the study described in this report has been to perform numerical simulations of the hydrogeological system from post-closure and throughout the temperate period up until the receding shoreline leaves the modelling domain at around 15,000 AD. Besides providing quantitative results for the immediate temperate period following post-closure, these results are also intended to give a qualitative indication of the evolution of the groundwater system during future temperate periods within an ongoing cycle of glacial/inter-glacial events

  1. Groundwater recharge and flow on Montserrat, West Indies: Insights from groundwater dating

    Directory of Open Access Journals (Sweden)

    Brioch Hemmings

    2015-09-01

    New hydrological insights: δ2H and δ18O analysis indicates uniform recharge elevations for groundwaters on Montserrat. CFC-11 and CFC-12 analysis reveals age differences between isotopically similar, high elevation springs and low elevation aquifer waters. Low CFC concentrations within a confined low elevation aquifer suggest water ages of ∼45 years. High CFC concentrations in the northern and western springs are explained by rapid infiltration of cool (high CFC concentration rainfall into saturated compartments, with flow through the vadose zone to the phreatic zone dominated by compartment flow. Lower CFC concentrations in a number of aligned warmer springs suggest a contribution from older, warmer waters from depth. Temperatures and CFC concentrations indicate older component supply rates of up to 8 L/s to the highest yielding spring on Centre Hills, with contributions of up to 75% in the warmest spring waters.

  2. SR-Site groundwater flow modelling methodology, setup and results

    International Nuclear Information System (INIS)

    Selroos, Jan-Olof; Follin, Sven

    2010-12-01

    As a part of the license application for a final repository for spent nuclear fuel at Forsmark, the Swedish Nuclear Fuel and Waste Management Company (SKB) has undertaken three groundwater flow modelling studies. These are performed within the SR-Site project and represent time periods with different climate conditions. The simulations carried out contribute to the overall evaluation of the repository design and long-term radiological safety. Three time periods are addressed; the Excavation and operational phases, the Initial period of temperate climate after closure, and the Remaining part of the reference glacial cycle. The present report is a synthesis of the background reports describing the modelling methodology, setup, and results. It is the primary reference for the conclusions drawn in a SR-Site specific context concerning groundwater flow during the three climate periods. These conclusions are not necessarily provided explicitly in the background reports, but are based on the results provided in these reports. The main results and comparisons presented in the present report are summarised in the SR-Site Main report

  3. SR-Site groundwater flow modelling methodology, setup and results

    Energy Technology Data Exchange (ETDEWEB)

    Selroos, Jan-Olof (Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)); Follin, Sven (SF GeoLogic AB, Taeby (Sweden))

    2010-12-15

    As a part of the license application for a final repository for spent nuclear fuel at Forsmark, the Swedish Nuclear Fuel and Waste Management Company (SKB) has undertaken three groundwater flow modelling studies. These are performed within the SR-Site project and represent time periods with different climate conditions. The simulations carried out contribute to the overall evaluation of the repository design and long-term radiological safety. Three time periods are addressed; the Excavation and operational phases, the Initial period of temperate climate after closure, and the Remaining part of the reference glacial cycle. The present report is a synthesis of the background reports describing the modelling methodology, setup, and results. It is the primary reference for the conclusions drawn in a SR-Site specific context concerning groundwater flow during the three climate periods. These conclusions are not necessarily provided explicitly in the background reports, but are based on the results provided in these reports. The main results and comparisons presented in the present report are summarised in the SR-Site Main report.

  4. Prediction of radionuclide migration in the geosphere: is the porous-flow model adequate

    International Nuclear Information System (INIS)

    Neretnieks, I.

    1982-01-01

    Practically all models used today to describe radionuclide migration in geologic media are based on the concept of flow in porous media. Recently it has been questioned if Fickian dispersion is the most important dispersion mechanism. Field observations of dispersion indicate that the dispersion coefficient increases with observation distance. This should not be the case in a homogeneous porous medium. For a medium with essentially independent channels, on the other hand, such an effect can be predicted. In some calculated examples it is shown that the use of the Fickian dispersion mechanism will very seriously underestimate the radionuclide concentration at a point downstream if the spreading mechanism in reality is channelling. The consequences of the often-used assumption that the interaction between the radionuclides and the rock is instantaneous is also discussed. It has been shown that in sparsely fissured crystalline rock the whole rock mass will not be able to participate in the sorption reactions, because the radionuclides will not have time to penetrate all through the large blocks. On the other hand, the assumption that only the surface of the fissures interacts with the radionuclides is likely to be an extremely conservative assumption in view of some recent diffusion experiments in crystalline rocks performed in our laboratories and at the Canadian Geologic Survey. Some experimental results on radionuclide migration in a single natural fissure under well-controlled conditions in the laboratory are also presented and interpreted using a model which includes channelling, surface sorption, diffusion in the rock matrix and sorption in the rock matrix. Some implications of these mechanisms in predicting radionuclide migration in the geosphere are discussed and compared with what a porous-flow model would predict

  5. Measurement of Finger Blood Flow in Raynauds Phenomenon by Radionuclide Angiography

    International Nuclear Information System (INIS)

    Lim, Sang Moo; Chung, June Key; Lee, Myung Chul; Kim, Sang Joon; Choi, Sung Jae; Koh, Chang Soon

    1987-01-01

    In Raynauds phenomenon, the authors measured finger blood flow after ice water exposure by analyzing the time activity curve of radionuclide angiography on both hands. The results were as follows: 1) The digital blood flow did not decrease after ice water exposure in normal subjects. 2) In the patients with Raynauds phenomenon, there were two groups: the one had decreased digital blood flow after cold exposure, and the other had paradoxically increased digital blood flow after cold exposure. 3) There was no difference in the digital blood flow of hand in room temperature between the normal and the patients with reduced digital blood flow after cold exposure, but the digital blood flow of the hand in room temperature was markedly reduced in the patients with paradoxically increased flow after cold exposure. 4) In the static image the difference was not significant in comparison with the dynamic study, because it represents pooling of the blood in the vein rather than flow. 5) After the treatment with nifedipine, the digital blood flow increased. In conclusion, the radionuclide angiography was useful in measuring the digital blood flow in Raynauds phenomenon, and further studies with various drugs is expected.

  6. Groundwater Recharge and Flow Processes in Taihang Mountains, a Semi-humid Region, North China

    Science.gov (United States)

    Sakakibara, Koichi; Tsujimura, Maki; Song, Xianfang; Zhang, Jie

    2015-04-01

    Groundwater flow/recharge variations in time and space are crucial for effective water management especially in semi-arid and semi-humid regions. In order to reveal comprehensive groundwater flow/recharge processes in a catchment with a large topographical relief and seasonal hydrological variations, intensive field surveys were undertaken at 4 times in different seasons (June 2011, August 2012, November 2012, February 2014) in the Wangkuai watershed, Taihang mountains, which is a main groundwater recharge area of the North China Plain. The groundwater, spring, stream water and reservoir water were taken, and inorganic solute constituents and stable isotopes of oxygen-18 and deuterium were determined on all water samples. Also, the stream flow rate and the depth of groundwater table were observed. The stable isotopic compositions and inorganic solute constituents in the groundwater are depleted and shown similar values as those of the surface water at the mountain-plain transitional area. Additionally, the groundwater in the vicinity of the Wangkuai Reservoir presents clearly higher stable isotopic compositions and lower d-excess than those of the stream water, indicating the groundwater around the reservoir is affected by evaporation same as the Wangkuai Reservoir itself. Hence, the surface water in the mountain-plain transitional area and Wangkuai Reservoir are principal groundwater recharge sources. An inversion analysis and simple mixing model were applied in the Wangkuai watershed using stable isotopes of oxygen-18 and deuterium to construct a groundwater flow model. The model shows that multi-originated groundwater flows from upstream to downstream along topography with certain mixing. In addition, the groundwater recharge occurs dominantly at the altitude from 421 m to 953 m, and the groundwater recharge rate by the Wangkuai Reservoir is estimated to be 2.4 % of the total groundwater recharge in the Wangkuai watershed. Therefore, the stream water and

  7. Radionuclide investigation of the blood flow in tumor and normal rat tissues in induced hyperglycemia

    International Nuclear Information System (INIS)

    Istomin, Yu.P.; Shitikov, B.D.; Markova, L.V.

    1991-01-01

    Radionuclide angiography was performed in rats with transplantable tumors. Induced hyperglycemia was shown to result in blood flow inhibition in tumor and normal tissues of tumor-bearing rats. Some differences were revealed in a degree of reversibility of blood flow disorders in tissues of the above strains. The results obtained confirmed the advisability of radiation therapy at the height of a decrease in tumor blood

  8. Effect of region assignment on relative renal blood flow estimates using radionuclides

    International Nuclear Information System (INIS)

    Harris, C.C.; Ford, K.K.; Coleman, R.E.; Dunnick, N.R.

    1984-01-01

    To determine the value of the initial phase of the Tc-99m DTPA renogram in the direct estimation of relative renal blood flow in dogs, the ratios of the slopes of renal time-activity curves were compared with the ratios of measured blood flow. Radionuclide results were dependent on region-of-interest (ROI) and background ROI assignment, and correlated well with measured relative flow only with a maximum renal outline region. Curve slope ratios correlated well with measured flow ratios with and without background correction, while 1- to 2-minute uptake ratios correlated well only when corrected for background

  9. Understanding large scale groundwater flow in fractured crystalline rocks to aid in repository siting

    International Nuclear Information System (INIS)

    Davison, C.; Brown, A.; Gascoyne, M.; Stevenson, D.; Ophori, D.

    2000-01-01

    Atomic Energy of Canada Limited (AECL) conducted a ten-year long groundwater flow study of a 1050 km 2 region of fractured crystalline rock in southeastern Manitoba to illustrate how an understanding of large scale groundwater flow can be used to assist in selecting a hydraulically favourable location for the deep geological disposal of nuclear fuel waste. The study involved extensive field investigations that included the drilling testing, sampling and monitoring of twenty deep boreholes distributed at detailed study areas across the region. The surface and borehole geotechnical investigations were used to construct a conceptual model of the main litho-structural features that controlled groundwater flow through the crystalline rocks of the region. Eighty-three large fracture zones and other spatial domains of moderately fractured and sparsely fractured rocks were represented in a finite element model of the area to simulate regional groundwater flow. The groundwater flow model was calibrated to match the observed groundwater recharge rate and the hydraulic heads measured in the network of deep boreholes. Particle tracking was used to determine the pathways and travel times from different depths in the velocity field of the calibrated groundwater flow model. The results were used to identify locations in the regional flow field that maximize the time it takes for groundwater to travel to surface discharge areas through long, slow groundwater pathways. One of these locations was chosen as a good hypothetical location for situating a nuclear fuel waste disposal vault at 750 m depth. (authors)

  10. Estimation of groundwater flow rate using the decay of 222Rn in a well

    International Nuclear Information System (INIS)

    Hamada, Hiromasa

    1999-01-01

    A method of estimating groundwater flow rate using the decay of 222 Rn in a well was investigated. Field application revealed that infiltrated water (i.e., precipitation, pond water and irrigation water) accelerated groundwater flow. In addition, the depth at which groundwater was influenced by surface water was determined. The velocity of groundwater in a test well was estimated to be of the order of 10 -6 cm s -1 , based on the ratio of 222 Rn concentration in groundwater before and after it flowed into the well. This method is applicable for monitoring of groundwater flow rate where the velocity in a well is from 10 -5 to 10 -6 cm s -1

  11. Representation of an open repository in groundwater flow models

    International Nuclear Information System (INIS)

    Painter, Scott; Sun, Alexander

    2005-08-01

    The effect of repository tunnels on groundwater flow has been identified as a potential issue for the nuclear waste repository being considered by SKB for a fractured granite formation in Sweden. In particular, the following pre-closure and post-closure processes have been identified as being important: inflows into open tunnels as functions of estimated grouting efficiencies, drawdown of the water table in the vicinity of the repository, upcoming of saline water, 'turnover' of surface water in the upper bedrock, and resaturation of backfilled tunnels following repository closure. The representation of repository tunnels within groundwater models is addressed in this report. The primary focus is on far-field flow that is modeled with a continuum porous medium approximation. Of particular interest are the consequences of the tunnel representation on the transient response of the groundwater system to repository operations and repository closure, as well as modeling issues such as how the water-table free surface and the coupling to near-surface hydrogeology should be handled. The overall objectives are to understand the consequences of current representations and to identify appropriate approximations for representing open tunnels in future groundwater modeling studies. The following conclusions can be drawn from the results of the simulations: 1. Two-phase flow may be induced in the vicinity of repository tunnels during repository pre-closure operations, but the formation of a two-phase flow region will not significantly affect far-field flow or inflows into tunnels. 2. The water table will be drawn down to the repository horizon and tunnel inflows will reach a steady-state value within about 5 years. 3. Steady-state inflows at the repository edge are estimated to be about 250 m 3 /year per meter of tunnel. Inflows will be greater during the transient de-watering period and less for tunnel locations closer to the repository center. 4. Significant amounts of water

  12. Representation of an open repository in groundwater flow models

    Energy Technology Data Exchange (ETDEWEB)

    Painter, Scott; Sun, Alexander [Southwest Research Inst., San Antonio, TX (United States). Center for Nuclear Waste Regulatory Analyses

    2005-08-01

    The effect of repository tunnels on groundwater flow has been identified as a potential issue for the nuclear waste repository being considered by SKB for a fractured granite formation in Sweden. In particular, the following pre-closure and post-closure processes have been identified as being important: inflows into open tunnels as functions of estimated grouting efficiencies, drawdown of the water table in the vicinity of the repository, upcoming of saline water, 'turnover' of surface water in the upper bedrock, and resaturation of backfilled tunnels following repository closure. The representation of repository tunnels within groundwater models is addressed in this report. The primary focus is on far-field flow that is modeled with a continuum porous medium approximation. Of particular interest are the consequences of the tunnel representation on the transient response of the groundwater system to repository operations and repository closure, as well as modeling issues such as how the water-table free surface and the coupling to near-surface hydrogeology should be handled. The overall objectives are to understand the consequences of current representations and to identify appropriate approximations for representing open tunnels in future groundwater modeling studies. The following conclusions can be drawn from the results of the simulations: 1. Two-phase flow may be induced in the vicinity of repository tunnels during repository pre-closure operations, but the formation of a two-phase flow region will not significantly affect far-field flow or inflows into tunnels. 2. The water table will be drawn down to the repository horizon and tunnel inflows will reach a steady-state value within about 5 years. 3. Steady-state inflows at the repository edge are estimated to be about 250 m{sup 3}/year per meter of tunnel. Inflows will be greater during the transient de-watering period and less for tunnel locations closer to the repository center. 4. Significant

  13. STRING 3: An Advanced Groundwater Flow Visualization Tool

    Science.gov (United States)

    Schröder, Simon; Michel, Isabel; Biedert, Tim; Gräfe, Marius; Seidel, Torsten; König, Christoph

    2016-04-01

    The visualization of 3D groundwater flow is a challenging task. Previous versions of our software STRING [1] solely focused on intuitive visualization of complex flow scenarios for non-professional audiences. STRING, developed by Fraunhofer ITWM (Kaiserslautern, Germany) and delta h Ingenieurgesellschaft mbH (Witten, Germany), provides the necessary means for visualization of both 2D and 3D data on planar and curved surfaces. In this contribution we discuss how to extend this approach to a full 3D tool and its challenges in continuation of Michel et al. [2]. This elevates STRING from a post-production to an exploration tool for experts. In STRING moving pathlets provide an intuition of velocity and direction of both steady-state and transient flows. The visualization concept is based on the Lagrangian view of the flow. To capture every detail of the flow an advanced method for intelligent, time-dependent seeding is used building on the Finite Pointset Method (FPM) developed by Fraunhofer ITWM. Lifting our visualization approach from 2D into 3D provides many new challenges. With the implementation of a seeding strategy for 3D one of the major problems has already been solved (see Schröder et al. [3]). As pathlets only provide an overview of the velocity field other means are required for the visualization of additional flow properties. We suggest the use of Direct Volume Rendering and isosurfaces for scalar features. In this regard we were able to develop an efficient approach for combining the rendering through raytracing of the volume and regular OpenGL geometries. This is achieved through the use of Depth Peeling or A-Buffers for the rendering of transparent geometries. Animation of pathlets requires a strict boundary of the simulation domain. Hence, STRING needs to extract the boundary, even from unstructured data, if it is not provided. In 3D we additionally need a good visualization of the boundary itself. For this the silhouette based on the angle of

  14. Groundwater flow modelling of an abandoned partially open repository

    Energy Technology Data Exchange (ETDEWEB)

    Bockgaard, Niclas (Golder Associates AB (Sweden))

    2010-12-15

    As a part of the license application, according to the nuclear activities act, for a final repository for spent nuclear fuel at Forsmark, the Swedish Nuclear Fuel and Waste Management Company (SKB) has undertaken a series of groundwater flow modelling studies. These represent time periods with different hydraulic conditions and the simulations carried out contribute to the overall evaluation of the repository design and long-term radiological safety. The modelling study presented here serves as an input for analyses of so-called future human actions that may affect the repository. The objective of the work was to investigate the hydraulic influence of an abandoned partially open repository. The intention was to illustrate a pessimistic scenario of the effect of open tunnels in comparison to the reference closure of the repository. The effects of open tunnels were studied for two situations with different boundary conditions: A 'temperate' case with present-day boundary conditions and a generic future 'glacial' case with an ice sheet covering the repository. The results were summarized in the form of analyses of flow in and out from open tunnels, the effect on hydraulic head and flow in the surrounding rock volume, and transport performance measures of flow paths from the repository to surface

  15. Groundwater flow modelling of an abandoned partially open repository

    International Nuclear Information System (INIS)

    Bockgaard, Niclas

    2010-12-01

    As a part of the license application, according to the nuclear activities act, for a final repository for spent nuclear fuel at Forsmark, the Swedish Nuclear Fuel and Waste Management Company (SKB) has undertaken a series of groundwater flow modelling studies. These represent time periods with different hydraulic conditions and the simulations carried out contribute to the overall evaluation of the repository design and long-term radiological safety. The modelling study presented here serves as an input for analyses of so-called future human actions that may affect the repository. The objective of the work was to investigate the hydraulic influence of an abandoned partially open repository. The intention was to illustrate a pessimistic scenario of the effect of open tunnels in comparison to the reference closure of the repository. The effects of open tunnels were studied for two situations with different boundary conditions: A 'temperate' case with present-day boundary conditions and a generic future 'glacial' case with an ice sheet covering the repository. The results were summarized in the form of analyses of flow in and out from open tunnels, the effect on hydraulic head and flow in the surrounding rock volume, and transport performance measures of flow paths from the repository to surface

  16. Sensitivity Analysis for Steady State Groundwater Flow Using Adjoint Operators

    Science.gov (United States)

    Sykes, J. F.; Wilson, J. L.; Andrews, R. W.

    1985-03-01

    Adjoint sensitivity theory is currently being considered as a potential method for calculating the sensitivity of nuclear waste repository performance measures to the parameters of the system. For groundwater flow systems, performance measures of interest include piezometric heads in the vicinity of a waste site, velocities or travel time in aquifers, and mass discharge to biosphere points. The parameters include recharge-discharge rates, prescribed boundary heads or fluxes, formation thicknesses, and hydraulic conductivities. The derivative of a performance measure with respect to the system parameters is usually taken as a measure of sensitivity. To calculate sensitivities, adjoint sensitivity equations are formulated from the equations describing the primary problem. The solution of the primary problem and the adjoint sensitivity problem enables the determination of all of the required derivatives and hence related sensitivity coefficients. In this study, adjoint sensitivity theory is developed for equations of two-dimensional steady state flow in a confined aquifer. Both the primary flow equation and the adjoint sensitivity equation are solved using the Galerkin finite element method. The developed computer code is used to investigate the regional flow parameters of the Leadville Formation of the Paradox Basin in Utah. The results illustrate the sensitivity of calculated local heads to the boundary conditions. Alternatively, local velocity related performance measures are more sensitive to hydraulic conductivities.

  17. Numerical simulation of groundwater flow for the Yakima River basin aquifer system, Washington

    Science.gov (United States)

    Ely, D.M.; Bachmann, M.P.; Vaccaro, J.J.

    2011-01-01

    A regional, three-dimensional, transient numerical model of groundwater flow was constructed for the Yakima River basin aquifer system to better understand the groundwater-flow system and its relation to surface-water resources. The model described in this report can be used as a tool by water-management agencies and other stakeholders to quantitatively evaluate proposed alternative management strategies that consider the interrelation between groundwater availability and surface-water resources.

  18. Determination of uteroplacental blood flow by a radionuclide technique

    International Nuclear Information System (INIS)

    Rosati, P.; Exacuostos, C.; Bellati, U.; Maini, C.L.; Bonetti, M.G.; Galli, G.

    1987-01-01

    The placental blood flow was determined using a non-invasive radioisotopic approach, with the intravenous administration of 113m In (37 MBq). The method was employed in 20 normal pregnancies, in 24 patients with intrauterine growth retardation, in 8 patients with iso-Rh-incompatibility and in 9 patients with gestational diabetes. In the group with intrauterine growth retardation 2 pregnancies with extensive fetal malformations were included. In one case without evident histological placental alteration the index was 3.94 at 34 weeks of gestation and 5.62 at 36 weeks of gestation. In the second one with placental infarcts the index was 3.46 at 38 weeks of gestation. Normal pregnancies showed a flow index of 5.50 ± 1.57 units compared to the pathological pregnancies value of 2.74 ± 0.90 units. The method is very well suited to clinical evaluation of placental blood flow. (author)

  19. Spatial variability analysis of combining the water quality and groundwater flow model to plan groundwater and surface water management in the Pingtung plain

    Science.gov (United States)

    Chen, Ching-Fang; Chen, Jui-Sheng; Jang, Cheng-Shin

    2014-05-01

    As a result of rapid economic growth in the Pingtung Plain, the use of groundwater resources has changed dramatically. The groundwater is quite rich in the Pingtung plain and the most important water sources. During the several decades, a substantial amount of groundwater has been pumped for the drinking, irrigation and aquaculture water supplies. However, because the sustainable use concept of groundwater resources is lack, excessive pumping of groundwater causes the occurrence of serious land subsidence and sea water intrusion. Thus, the management and conservation of groundwater resources in the Pingtung plain are considerably critical. This study aims to assess the conjunct use effect of groundwater and surface water in the Pingtung plain on recharge by reducing the amount of groundwater extraction. The groundwater quality variability and groundwater flow models are combined to spatially analyze potential zones of groundwater used for multi-purpose in the Pingtung Plain. First, multivariate indicator kriging (MVIK) is used to analyze spatial variability of groundwater quality based on drinking, aquaculture and irrigation water quality standards, and probabilistically delineate suitable zones in the study area. Then, the groundwater flow model, Processing MODFLOW (PMWIN), is adopted to simulate groundwater flow. The groundwater flow model must be conducted by the calibration and verification processes, and the regional groundwater recovery is discussed when specified water rights are replaced by surface water in the Pingtung plain. Finally, the most suitable zones of reducing groundwater use are determined for multi-purpose according to combining groundwater quality and quantity. The study results can establish a sound and low-impact management plan of groundwater resources utilization for the multi-purpose groundwater use, and prevent decreasing ground water tables, and the occurrence of land subsidence and sea water intrusion in the Pingtung plain.

  20. Regional Groundwater Flow Assessment in a Prospective High-Level Radioactive Waste Repository of China

    Directory of Open Access Journals (Sweden)

    Xiaoyuan Cao

    2017-07-01

    Full Text Available The production of nuclear energy will result in high-level radioactive waste (HLRW, which brings potential environmental dangers. Selecting a proper disposal repository is a crucial step in the development of nuclear energy. This paper introduces firstly the hydrogeological conditions of the Beishan area in China. Next, a regional groundwater model is constructed using a multiphase flow simulator to analyze the groundwater flow pattern in the Beishan area. Model calibration shows that the simulated and observed hydraulic heads match well, and the simulated regional groundwater flow pattern is similar to the surface flow pattern from the channel network, indicating that the groundwater flow is mainly dependent on the topography. In addition, the simulated groundwater storage over the period from 2003 to 2014 is similar to the trend derived from the Gravity Recovery and Climate Experiment satellite-derived results. Last, the established model is used to evaluate the influences of the extreme climate and regional faults on the groundwater flow pattern. It shows that they do not have a significant influence on the regional groundwater flow patterns. This study will provide a preliminary reference for the regional groundwater flow assessment in the site of the HLRW in China.

  1. ENVIRONMENTAL RESEARCH BRIEF : ANALYTIC ELEMENT MODELING OF GROUND-WATER FLOW AND HIGH PERFORMANCE COMPUTING

    Science.gov (United States)

    Several advances in the analytic element method have been made to enhance its performance and facilitate three-dimensional ground-water flow modeling in a regional aquifer setting. First, a new public domain modular code (ModAEM) has been developed for modeling ground-water flow ...

  2. Development and application of groundwater flow meter in fractured rocks: Measurement of velocity and direction of groundwater flow in single well

    International Nuclear Information System (INIS)

    Kawanishi, M.; Miyakawa, K.; Hirata, Y.

    2001-01-01

    For the confirmation of safety for the geological disposal of radioactive wastes, it is very important to demonstrate the groundwater flow by in-situ investigation in the deep underground. We have developed a groundwater flow meter to measure simultaneously the velocity and direction of groundwater flow by means of detecting the electric potential difference between the groundwater to evaluate and the distilled water as a tracer in a single well. In this paper, we describe the outline of the groundwater flow meter system developed by CRIEPI and Taisei-Kiso-Sekkei Co. Ltd. and the evaluation methodology for observed data by using it in fractured rocks. Furthermore, applied results to in-situ tests at the Tounou mine of Japan Nuclear Fuel Cycle Development Institute (JNC) and the Aespoe Hard Rock Laboratory (HRL) of Swedish Nuclear Fuel and Waste Management Co. (SK) are described. Both sites are different type of fractured rock formations of granite. From these results, it was made clear that this flow meter system can be practically used to measure the groundwater flow direction and velocity as low as order of 1x10 -3 ∼10 -7 cm/sec. (author)

  3. U-234/U-238 ratio: Qualitative estimate of groundwater flow in Rocky Flats monitoring wells

    International Nuclear Information System (INIS)

    Laul, J.C.

    1994-01-01

    Groundwater movement through various pathways is the primary mechanism for the transport of radionuclides and trace elements in a water/rock interaction. About three dozen wells, installed in the Rocky Flats Plant (RFP) Solar Evaporation Ponds (SEP) area, are monitored quarterly to evaluate the extent of any lateral and downgradient migration of contaminants from the Solar Evaporation Ponds: 207-A; 207-B North, 207-B Center, and 207-B South; and 207-C. The Solar Ponds are the main source for the various contaminants: radionuclides (U-238, U-234, Pu-239, 240 and Am-241); anions; and trace metals to groundwaters. The U-238 concentrations in Rocky Flats groundwaters vary from 2 (CO 3 ) 2 2- , because of the predominant bicarbonate medium

  4. Groundwater flow modelling of the excavation and operational phases - Forsmark

    International Nuclear Information System (INIS)

    Svensson, Urban; Follin, Sven

    2010-07-01

    As a part of the license application for a final repository for spent nuclear fuel at Forsmark, the Swedish Nuclear Fuel and Waste Management Company (SKB) has undertaken a series of groundwater flow modelling studies. These represent time periods with different climate conditions and the simulations carried out contribute to the overall evaluation of the repository design and long-term radiological safety. The modelling study reported here presents calculated inflow rates, drawdown of the groundwater table and upconing of deep saline water for different levels of grouting efficiency during the excavation and operational phases of a final repository at Forsmark. The inflow calculations are accompanied by a sensitivity study, which among other matters handles the impact of parameter heterogeneity, different deposition hole rejection criteria, and the SFR facility (the repository for short-lived radioactive waste located approximately 1 km to the north of the investigated candidate area for a final repository at Forsmark). The report also presents tentative modelling results for the duration of the saturation phase, which starts once the used parts of the repository are being backfilled

  5. Groundwater flow modelling of the excavation and operational phases - Forsmark

    Energy Technology Data Exchange (ETDEWEB)

    Svensson, Urban (Computer-aided Fluid Engineering AB, Lyckeby (Sweden)); Follin, Sven (SF GeoLogic AB, Taeby (Sweden))

    2010-07-15

    As a part of the license application for a final repository for spent nuclear fuel at Forsmark, the Swedish Nuclear Fuel and Waste Management Company (SKB) has undertaken a series of groundwater flow modelling studies. These represent time periods with different climate conditions and the simulations carried out contribute to the overall evaluation of the repository design and long-term radiological safety. The modelling study reported here presents calculated inflow rates, drawdown of the groundwater table and upconing of deep saline water for different levels of grouting efficiency during the excavation and operational phases of a final repository at Forsmark. The inflow calculations are accompanied by a sensitivity study, which among other matters handles the impact of parameter heterogeneity, different deposition hole rejection criteria, and the SFR facility (the repository for short-lived radioactive waste located approximately 1 km to the north of the investigated candidate area for a final repository at Forsmark). The report also presents tentative modelling results for the duration of the saturation phase, which starts once the used parts of the repository are being backfilled.

  6. Assessment of the radionuclide fluxes from the Chernobyl shelter and cooling pond into pripyat river and groundwater

    International Nuclear Information System (INIS)

    Zheleznyak, M.; Onishi, Y.; Kivva, S.; Dzjuba, N.; Dvorzhak, A.

    2004-01-01

    The destroyed Chernobyl Unit 4 under the constructed 'shelter' and the Chernobyl Cooling Pond are potentially most hazardous object in the Chernobyl zone. The model based assessment of the consequences of the Shelter collapse on surface water contamination was provided in the frame of the Environmental Impact Assessment of New Safe Confinement (NSC), designed above the Shelter. For the conservative worst hydrological scenario the wind direction was taken to deposit the maximum amount of radionuclides directly on the Pripyat River surface and flood plain upstream the Chernobyl NPP. Assuming the atmospheric dispersion of 8 kg of reactor fuel due to the Shelter collapse, it was assessed that 2.4 TBq of 137 Cs and 1.1 TBq of 90 Sr will be released into the Pripyat River within 3 days. The 1-D model RIVTOX was used to simulate the propagation of released radionuclides through Dniper reservoir cascade. It was shown that the concentrations of 137 Cs and 90 Sr in Dnieper reservoirs for the simulated scenario will not be higher than during last high spring flood 1999. The impact of the NSC on the diminishing of the surface water and groundwater contamination was simulated. Most of the initial contamination of the Chernobyl Cooling Pond (CCP) by long lived radionuclides, such as 137 Cs, 90 Sr and transuranics, has accumulated in its bottom sediments. The water elevation in the CCP is at 6 m higher than in the neighbouring Pripyat river. The scenario of a collapse of CCP's dam, has been considered, which hypothetical cause can be earthquake, dam score during high flood, terrorist attack. The propagation of contaminated water and sediments from the CCP dam breach through the Pripyat River flood plain, downstream river and than through the Dnieper reservoirs was modelled by the chain of 2-D and 1-D models. (author)

  7. HYDRASTAR - a code for stochastic simulation of groundwater flow

    International Nuclear Information System (INIS)

    Norman, S.

    1992-05-01

    The computer code HYDRASTAR was developed as a tool for groundwater flow and transport simulations in the SKB 91 safety analysis project. Its conceptual ideas can be traced back to a report by Shlomo Neuman in 1988, see the reference section. The main idea of the code is the treatment of the rock as a stochastic continuum which separates it from the deterministic methods previously employed by SKB and also from the discrete fracture models. The current report is a comprehensive description of HYDRASTAR including such topics as regularization or upscaling of a hydraulic conductivity field, unconditional and conditional simulation of stochastic processes, numerical solvers for the hydrology and streamline equations and finally some proposals for future developments

  8. Groundwater flow processes and mixing in active volcanic systems: the case of Guadalajara (Mexico)

    Science.gov (United States)

    Hernández-Antonio, A.; Mahlknecht, J.; Tamez-Meléndez, C.; Ramos-Leal, J.; Ramírez-Orozco, A.; Parra, R.; Ornelas-Soto, N.; Eastoe, C. J.

    2015-09-01

    Groundwater chemistry and isotopic data from 40 production wells in the Atemajac and Toluquilla valleys, located in and around the Guadalajara metropolitan area, were determined to develop a conceptual model of groundwater flow processes and mixing. Stable water isotopes (δ2H, δ18O) were used to trace hydrological processes and tritium (3H) to evaluate the relative contribution of modern water in samples. Multivariate analysis including cluster analysis and principal component analysis were used to elucidate distribution patterns of constituents and factors controlling groundwater chemistry. Based on this analysis, groundwater was classified into four groups: cold groundwater, hydrothermal groundwater, polluted groundwater and mixed groundwater. Cold groundwater is characterized by low temperature, salinity, and Cl and Na concentrations and is predominantly of Na-HCO3-type. It originates as recharge at "La Primavera" caldera and is found predominantly in wells in the upper Atemajac Valley. Hydrothermal groundwater is characterized by high salinity, temperature, Cl, Na and HCO3, and the presence of minor elements such as Li, Mn and F. It is a mixed-HCO3 type found in wells from Toluquilla Valley and represents regional flow circulation through basaltic and andesitic rocks. Polluted groundwater is characterized by elevated nitrate and sulfate concentrations and is usually derived from urban water cycling and subordinately from agricultural return flow. Mixed groundwaters between cold and hydrothermal components are predominantly found in the lower Atemajac Valley. Twenty-seven groundwater samples contain at least a small fraction of modern water. The application of a multivariate mixing model allowed the mixing proportions of hydrothermal fluids, polluted waters and cold groundwater in sampled water to be evaluated. This study will help local water authorities to identify and dimension groundwater contamination, and act accordingly. It may be broadly applicable to

  9. Very deep hole concept. Thermal effects on groundwater flow

    Energy Technology Data Exchange (ETDEWEB)

    Marsic, Niko; Grundfelt, Bertil; Wiborgh, Marie [Kemakta Konsult AB, Stockholm (Sweden)

    2006-09-15

    ,055 nodes. The results of the calculations were evaluated using tracking of particle starting in different positions in the deposition holes. The travel times for these particles to the surface were calculated. The particle tracking was performed for individual time steps assuming that the conditions of that time step remained constant throughout the particle travel times. This is of course not true, in particular as the calculated travel times are much longer that the duration of the heat pulse from the deposited spent fuel. A more refined variant of the grid including 1,245,680 finite elements corresponding to 2,525,744 nodes was tested in order to verify that the discretisation used was adequate. In this case, all elements inside the repository area and those closest to this area were refined by a factor of two in each of the three dimensions. The elements constituting the boreholes were left unchanged. The results of this test show that both the flow pattern and the calculated Darcy velocities are significantly affected by the disretisation while the calculated particle travel times were little influenced. Because of the little difference of travel times and due to the fact that the computational times of the larger grid were hard to manage within a reasonable project schedule, it was decided to use the smaller grid for the calculations. A large number of calculations were performed in which the sensitivity of the results with respect to different combinations of surface hydraulic gradients, heat output from the deposited spent fuel and fracture zone orientations was tested. In general, the calculated travel times for the particles are extremely long, in the order of 1-100 Myrs. The thermal output from the spent fuel is insufficient to alter the stability of the near-stagnant saline groundwater present at depth in the rock. However, the performed sensitivity analysis showed effects on the Darcy velocities, flow field and calculated hypothetical travel times, but the

  10. Very deep hole concept. Thermal effects on groundwater flow

    International Nuclear Information System (INIS)

    Marsic, Niko; Grundfelt, Bertil; Wiborgh, Marie

    2006-09-01

    results of the calculations were evaluated using tracking of particle starting in different positions in the deposition holes. The travel times for these particles to the surface were calculated. The particle tracking was performed for individual time steps assuming that the conditions of that time step remained constant throughout the particle travel times. This is of course not true, in particular as the calculated travel times are much longer that the duration of the heat pulse from the deposited spent fuel. A more refined variant of the grid including 1,245,680 finite elements corresponding to 2,525,744 nodes was tested in order to verify that the discretisation used was adequate. In this case, all elements inside the repository area and those closest to this area were refined by a factor of two in each of the three dimensions. The elements constituting the boreholes were left unchanged. The results of this test show that both the flow pattern and the calculated Darcy velocities are significantly affected by the disretisation while the calculated particle travel times were little influenced. Because of the little difference of travel times and due to the fact that the computational times of the larger grid were hard to manage within a reasonable project schedule, it was decided to use the smaller grid for the calculations. A large number of calculations were performed in which the sensitivity of the results with respect to different combinations of surface hydraulic gradients, heat output from the deposited spent fuel and fracture zone orientations was tested. In general, the calculated travel times for the particles are extremely long, in the order of 1-100 Myrs. The thermal output from the spent fuel is insufficient to alter the stability of the near-stagnant saline groundwater present at depth in the rock. However, the performed sensitivity analysis showed effects on the Darcy velocities, flow field and calculated hypothetical travel times, but the differences do

  11. PHAST--a program for simulating ground-water flow, solute transport, and multicomponent geochemical reactions

    Science.gov (United States)

    Parkhurst, David L.; Kipp, Kenneth L.; Engesgaard, Peter; Charlton, Scott R.

    2004-01-01

    The computer program PHAST simulates multi-component, reactive solute transport in three-dimensional saturated ground-water flow systems. PHAST is a versatile ground-water flow and solute-transport simulator with capabilities to model a wide range of equilibrium and kinetic geochemical reactions. The flow and transport calculations are based on a modified version of HST3D that is restricted to constant fluid density and constant temperature. The geochemical reactions are simulated with the geochemical model PHREEQC, which is embedded in PHAST. PHAST is applicable to the study of natural and contaminated ground-water systems at a variety of scales ranging from laboratory experiments to local and regional field scales. PHAST can be used in studies of migration of nutrients, inorganic and organic contaminants, and radionuclides; in projects such as aquifer storage and recovery or engineered remediation; and in investigations of the natural rock-water interactions in aquifers. PHAST is not appropriate for unsaturated-zone flow, multiphase flow, density-dependent flow, or waters with high ionic strengths. A variety of boundary conditions are available in PHAST to simulate flow and transport, including specified-head, flux, and leaky conditions, as well as the special cases of rivers and wells. Chemical reactions in PHAST include (1) homogeneous equilibria using an ion-association thermodynamic model; (2) heterogeneous equilibria between the aqueous solution and minerals, gases, surface complexation sites, ion exchange sites, and solid solutions; and (3) kinetic reactions with rates that are a function of solution composition. The aqueous model (elements, chemical reactions, and equilibrium constants), minerals, gases, exchangers, surfaces, and rate expressions may be defined or modified by the user. A number of options are available to save results of simulations to output files. The data may be saved in three formats: a format suitable for viewing with a text editor; a

  12. Uncertainty in simulated groundwater-quality trends in transient flow

    Science.gov (United States)

    Starn, J. Jeffrey; Bagtzoglou, Amvrossios; Robbins, Gary A.

    2013-01-01

    In numerical modeling of groundwater flow, the result of a given solution method is affected by the way in which transient flow conditions and geologic heterogeneity are simulated. An algorithm is demonstrated that simulates breakthrough curves at a pumping well by convolution-based particle tracking in a transient flow field for several synthetic basin-scale aquifers. In comparison to grid-based (Eulerian) methods, the particle (Lagrangian) method is better able to capture multimodal breakthrough caused by changes in pumping at the well, although the particle method may be apparently nonlinear because of the discrete nature of particle arrival times. Trial-and-error choice of number of particles and release times can perhaps overcome the apparent nonlinearity. Heterogeneous aquifer properties tend to smooth the effects of transient pumping, making it difficult to separate their effects in parameter estimation. Porosity, a new parameter added for advective transport, can be accurately estimated using both grid-based and particle-based methods, but predictions can be highly uncertain, even in the simple, nonreactive case.

  13. Phase II Groundwater Flow Model of Corrective Action Unit 98: Frenchman Flat, Nevada Test Site, Nye County, Nevada, Rev. No.: 0

    Energy Technology Data Exchange (ETDEWEB)

    John McCord

    2006-05-01

    The Phase II Frenchman Flat groundwater flow model is a key element in the ''Federal Facility Agreement and Consent Order'' (FFACO) (1996) corrective action strategy for the Underground Test Area (UGTA) Frenchman Flat corrective action unit (CAU). The objective of this integrated process is to provide an estimate of the vertical and horizontal extent of contaminant migration for each CAU to predict contaminant boundaries. A contaminant boundary is the model-predicted perimeter that defines the extent of radionuclide-contaminated groundwater from underground testing above background conditions exceeding the ''Safe Drinking Water Act'' (SDWA) standards. The contaminant boundary will be composed of both a perimeter boundary and a lower hydrostratigraphic unit (HSU) boundary. The computer model will predict the location of this boundary within 1,000 years and must do so at a 95 percent level of confidence. Additional results showing contaminant concentrations and the location of the contaminant boundary at selected times will also be presented. These times may include the verification period, the end of the five-year proof-of-concept period, as well as other times that are of specific interest. This report documents the development and implementation of the groundwater flow model for the Frenchman Flat CAU. Specific objectives of the Phase II Frenchman Flat flow model are to: (1) Incorporate pertinent information and lessons learned from the Phase I Frenchman Flat CAU models. (2) Develop a three-dimensional (3-D), mathematical flow model that incorporates the important physical features of the flow system and honors CAU-specific data and information. (3) Simulate the steady-state groundwater flow system to determine the direction and magnitude of groundwater fluxes based on calibration to Frenchman Flat hydrogeologic data. (4) Quantify the uncertainty in the direction and magnitude of groundwater flow due to uncertainty in

  14. Phase II Groundwater Flow Model of Corrective Action Unit 98: Frenchman Flat, Nevada Test Site, Nye County, Nevada, Rev. No.: 0

    International Nuclear Information System (INIS)

    John McCord

    2006-01-01

    The Phase II Frenchman Flat groundwater flow model is a key element in the ''Federal Facility Agreement and Consent Order'' (FFACO) (1996) corrective action strategy for the Underground Test Area (UGTA) Frenchman Flat corrective action unit (CAU). The objective of this integrated process is to provide an estimate of the vertical and horizontal extent of contaminant migration for each CAU to predict contaminant boundaries. A contaminant boundary is the model-predicted perimeter that defines the extent of radionuclide-contaminated groundwater from underground testing above background conditions exceeding the ''Safe Drinking Water Act'' (SDWA) standards. The contaminant boundary will be composed of both a perimeter boundary and a lower hydrostratigraphic unit (HSU) boundary. The computer model will predict the location of this boundary within 1,000 years and must do so at a 95 percent level of confidence. Additional results showing contaminant concentrations and the location of the contaminant boundary at selected times will also be presented. These times may include the verification period, the end of the five-year proof-of-concept period, as well as other times that are of specific interest. This report documents the development and implementation of the groundwater flow model for the Frenchman Flat CAU. Specific objectives of the Phase II Frenchman Flat flow model are to: (1) Incorporate pertinent information and lessons learned from the Phase I Frenchman Flat CAU models. (2) Develop a three-dimensional (3-D), mathematical flow model that incorporates the important physical features of the flow system and honors CAU-specific data and information. (3) Simulate the steady-state groundwater flow system to determine the direction and magnitude of groundwater fluxes based on calibration to Frenchman Flat hydrogeologic data. (4) Quantify the uncertainty in the direction and magnitude of groundwater flow due to uncertainty in parameter values and alternative component

  15. Relation of streams, lakes, and wetlands to groundwater flow systems

    Science.gov (United States)

    Winter, Thomas C.

    Surface-water bodies are integral parts of groundwater flow systems. Groundwater interacts with surface water in nearly all landscapes, ranging from small streams, lakes, and wetlands in headwater areas to major river valleys and seacoasts. Although it generally is assumed that topographically high areas are groundwater recharge areas and topographically low areas are groundwater discharge areas, this is true primarily for regional flow systems. The superposition of local flow systems associated with surface-water bodies on this regional framework results in complex interactions between groundwater and surface water in all landscapes, regardless of regional topographic position. Hydrologic processes associated with the surface-water bodies themselves, such as seasonally high surface-water levels and evaporation and transpiration of groundwater from around the perimeter of surface-water bodies, are a major cause of the complex and seasonally dynamic groundwater flow fields associated with surface water. These processes have been documented at research sites in glacial, dune, coastal, mantled karst, and riverine terrains. Résumé Les eaux de surface sont parties intégrantes des systèmes aquifères. Les eaux souterraines interagissent avec les eaux de surface dans presque tous les types d'environnements, depuis les petits ruisseaux, les lacs et les zones humides jusqu'aux bassins versants des vallées des grands fleuves et aux lignes de côte. Il est en général admis que les zones topographiquement hautes sont des lieux de recharge des aquifères et les zones basses des lieux de décharge, ce qui est le cas des grands systèmes aquifères régionaux. La superposition de systèmes locaux, associés à des eaux de surface, à l'organisation régionale d'écoulements souterrains résulte d'interactions complexes entre les eaux souterraines et les eaux de surface dans tous les environnements, quelle que soit la situation topographique régionale. Les processus

  16. The `Henry Problem' of `density-driven' groundwater flow versus Tothian `groundwater flow systems' with variable density: A review of the influential Biscayne aquifer data.

    Science.gov (United States)

    Weyer, K. U.

    2017-12-01

    Coastal groundwater flow investigations at the Biscayne Bay, south of Miami, Florida, gave rise to the concept of density-driven flow of seawater into coastal aquifers creating a saltwater wedge. Within that wedge, convection-driven return flow of seawater and a dispersion zone were assumed by Cooper et al. (1964) to be the cause of the Biscayne aquifer `sea water wedge'. This conclusion was based on the chloride distribution within the aquifer and on an analytical model concept assuming convection flow within a confined aquifer without taking non-chemical field data into consideration. This concept was later labelled the `Henry Problem', which any numerical variable density flow program must be able to simulate to be considered acceptable. Both, `density-driven flow' and Tothian `groundwater flow systems' (with or without variable density conditions) are driven by gravitation. The difference between the two are the boundary conditions. 'Density-driven flow' occurs under hydrostatic boundary conditions while Tothian `groundwater flow systems' occur under hydrodynamic boundary conditions. Revisiting the Cooper et al. (1964) publication with its record of piezometric field data (heads) showed that the so-called sea water wedge has been caused by discharging deep saline groundwater driven by gravitational flow and not by denser sea water. Density driven flow of seawater into the aquifer was not found reflected in the head measurements for low and high tide conditions which had been taken contemporaneously with the chloride measurements. These head measurements had not been included in the flow interpretation. The very same head measurements indicated a clear dividing line between shallow local fresh groundwater flow and saline deep groundwater flow without the existence of a dispersion zone or a convection cell. The Biscayne situation emphasizes the need for any chemical interpretation of flow pattern to be supported by head data as energy indicators of flow fields

  17. Radionuclides as natural tracers of the interaction between groundwater and surface water in the River Andarax, Spain.

    Science.gov (United States)

    Navarro-Martinez, Francisco; Salas Garcia, Alejandro; Sánchez-Martos, Francisco; Baeza Espasa, Antonio; Molina Sánchez, Luis; Rodríguez Perulero, Antonio

    2017-12-01

    The identification of specific aquifers that supply water to river systems is fundamental to understanding the dynamics of the rivers' hydrochemistry, particularly in arid and semiarid environments where river flow may be discontinuous. There are multiple methods to identify the source of river water. In this study of the River Andarax, in the Southeast of Spain, an analysis of natural tracers (physico-chemical parameters, uranium, radium and radon) in surface water and groundwater indicates that chemical parameters and uranium clearly identify the areas where there is groundwater-surface water interaction. The concentration of uranium found in the river defines two areas: the headwaters with U concentrations of 2 μg L -1 and the lower reaches, with U of 6 μg L -1 . Furthermore, variation in the 234 U/ 238 U isotopic ratio allowed us to detect the influence that groundwater from the carbonate aquifer has on surface water in the headwaters of the river, where the saline content is lower and the water has a calcium bicarbonate facies. The concentration of 226 Ra and 222 Rn are low in the surface waters: aquifer on the surface waters. The results of this study indicate the utility in the use of physico-chemical and radiological data conjointly as tracers of groundwater-surface water interaction in semiarid areas where the lithology of aquifers is diverse (carbonate and detritic) and where evaporitic rocks are present. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Impact of kinetics and flow path heterogeneity on nanoparticle/radionuclide migration

    International Nuclear Information System (INIS)

    Huber, Florian M.

    2011-01-01

    The prevailing PhD thesis experimentally investigates the impact of both sorption/desorption (reversibility) and reduction kinetics on radionuclide migration in synthetic and natural systems from the nano-to the centimeter scale. Furthermore, the impact of fracture heterogeneity on flow and solute/nanoparticle transport as a potential additional retardation mechanism is examined both on an experimental and numerical basis. The process of sorptive reduction of U(VI) to sparingly soluble tetravalent uranium by structural bound Fe(II) in magnetite shows fast kinetics (hours to a few days contact time). A clear correlation between the Fe(II) content on the magnetite surface and the amount of U(VI) was observed, that is, increasing U(IV) with increasing Fe(II). Moreover, a congruency between the measured Eh(SHE) and the U valence state can partly been derived within the analytical uncertainties of the redox potential measurements. Thus, secondary phases as the stainless steel corrosion product magnetite can have beneficial effects on radionuclide migration as an effective retardation pathway for redox sensitive radionuclides. Beside, the studies on U(VI) maghemite sorption show that oxidized surfaces can possess long-term reduction capacities further enhancing radionuclide retention. Concerning the colloid-facilitated radionuclide transport, the batch sorption reversibility studies revealed the significance of kinetically controlled radionuclide desorption from the colloidal phase and subsequent sorption to the fracture filling materials (independent of the mineralogy and/or size fraction). By this process, initially colloidal associated radionuclides like the tri-and tetravalent radionuclides Th, Pu and Am are effectively retarded leading to an increase in the residence time. These reversibility results need to be included in codes for simulating colloid-facilitated radionuclide transport to reduce the conservatism and degree of uncertainties in input parameters

  19. Impact of kinetics and flow path heterogeneity on nanoparticle/radionuclide migration

    Energy Technology Data Exchange (ETDEWEB)

    Huber, Florian M.

    2011-11-29

    The prevailing PhD thesis experimentally investigates the impact of both sorption/desorption (reversibility) and reduction kinetics on radionuclide migration in synthetic and natural systems from the nano-to the centimeter scale. Furthermore, the impact of fracture heterogeneity on flow and solute/nanoparticle transport as a potential additional retardation mechanism is examined both on an experimental and numerical basis. The process of sorptive reduction of U(VI) to sparingly soluble tetravalent uranium by structural bound Fe(II) in magnetite shows fast kinetics (hours to a few days contact time). A clear correlation between the Fe(II) content on the magnetite surface and the amount of U(VI) was observed, that is, increasing U(IV) with increasing Fe(II). Moreover, a congruency between the measured Eh(SHE) and the U valence state can partly been derived within the analytical uncertainties of the redox potential measurements. Thus, secondary phases as the stainless steel corrosion product magnetite can have beneficial effects on radionuclide migration as an effective retardation pathway for redox sensitive radionuclides. Beside, the studies on U(VI) maghemite sorption show that oxidized surfaces can possess long-term reduction capacities further enhancing radionuclide retention. Concerning the colloid-facilitated radionuclide transport, the batch sorption reversibility studies revealed the significance of kinetically controlled radionuclide desorption from the colloidal phase and subsequent sorption to the fracture filling materials (independent of the mineralogy and/or size fraction). By this process, initially colloidal associated radionuclides like the tri-and tetravalent radionuclides Th, Pu and Am are effectively retarded leading to an increase in the residence time. These reversibility results need to be included in codes for simulating colloid-facilitated radionuclide transport to reduce the conservatism and degree of uncertainties in input parameters

  20. Simulating the effects of a beaver dam on regional groundwater flow through a wetland

    Directory of Open Access Journals (Sweden)

    Kathleen Feiner

    2015-09-01

    New hydrological insights for the region: The construction of a beaver dam resulted in minimal changes to regional groundwater flow paths at this site, which is attributed to a clay unit underlying the peat, disconnecting this wetland from regional groundwater flow. However, groundwater discharge from the wetland pond increased by 90%. Simulating a scenario with the numerical model in which the wetland is connected to regional groundwater flow results in a much larger impact on flow paths. In the absence of the clay layer, the simulated construction of a beaver dam causes a 70% increase in groundwater discharge from the wetland pond and increases the surface area of both the capture zone and the discharge zone by 30% and 80%, respectively.

  1. Characterization of Co(III) EDTA-Reducing Bacteria in Metal- and Radionuclide-Contaminated Groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Weimin [Arizona State University; Gentry, Terry J [ORNL; Mehlhorn, Tonia L [ORNL; Carroll, Sue L [ORNL; Jardine, Philip M [ORNL; Zhou, Jizhong [University of Oklahoma, Norman

    2010-01-01

    The Waste Area Grouping 5 (WAG5) site at Oak Ridge National Laboratory has a potential to be a field site for evaluating the effectiveness of various bioremediation approaches and strategies. The site has been well studied in terms of its geological and geochemical properties over the past decade. However, despite the importance of microorganisms in bioremediation processes, the microbiological populations at the WAG5 site and their potential in bioremediation have not been similarly evaluated. In this study, we initiated research to characterize the microbial populations in WAG5 groundwater. Approximately 100 isolates from WAG5 groundwater were isolated and selected based on colony morphology. Fifty-five unique isolates were identified by BOX-PCR and subjected to further characterization. 16S rRNA sequences indicated that these isolates belong to seventeen bacterial genera including Alcaligenes (1 isolate), Aquamonas (1), Aquaspirillum (1), Bacillus (10), Brevundimonas (5), Caulobacter (7), Dechloromonas (2), Janibacter (1), Janthinobacterium (2), Lactobacillus (1), Paenibacillus (4), Pseudomonas (9), Rhodoferax (1), Sphingomonas (1), Stenotrophomonas (6), Variovorax (2), and Zoogloea (1). Metal respiration assays identified several isolates, which phylogenically belong or are close to Caulobacter, Stenotrophomonas, Bacillus, Paenibacillus and Pseudomonas, capable of reducing Co(III)EDTA- to Co(II)EDTA{sup 2-} using the defined M1 medium under anaerobic conditions. In addition, using WAG5 groundwater directly as the inoculants, we found that organisms associated with WAG5 groundwater can reduce both Fe(III) and Co(III) under anaerobic conditions. Further assays were then performed to determine the optimal conditions for Co(III) reduction. These assays indicated that addition of various electron donors including ethanol, lactate, methanol, pyruvate, and acetate resulted in metal reduction. These experiments will provide useful background information for future

  2. Quantifying sources of fine sediment supplied to post-fire debris flows using fallout radionuclide tracers

    Science.gov (United States)

    Smith, Hugh; Sheridan, Gary; Nyman, Petter; Child, David; Lane, Patrick; Hotchkis, Michael

    2013-04-01

    The supply of fine sediment and ash has been identified as an important factor contributing to the initiation of runoff-generated debris flows after fire. However, despite the significance of fines for post-fire debris flow generation, no investigations have sought to quantify sources of this material in debris flow affected catchments. In this study, we employ fallout radionuclides (Cs-137, excess Pb-210 and Pu-239,240) as tracers to measure proportional contributions of fine sediment (bank sources to levee and terminal fan deposits formed by post-fire debris flows in two forest catchments in southeastern Australia. While Cs-137 and excess Pb-210 have been widely used in sediment tracing studies, application of Pu as a tracer represents a recent development and was limited to only one catchment. The estimated range in hillslope surface contributions of fine sediment to individual debris flow deposits in each catchment was 22-69% and 32-74%, respectively. No systematic change in the source contributions to debris flow deposits was observed with distance downstream from channel initiation points. Instead, spatial variability in source contributions was largely influenced by the pattern of debris flow surges forming the deposits. Linking the sediment tracing with interpretation of depositional evidence allowed reconstruction of temporal sequences in sediment source contributions to debris flow surges. Hillslope source inputs dominated most elevated channel deposits such as marginal levees that were formed under peak flow conditions. This indicated the importance of hillslope runoff and sediment supply for debris flow generation in both catchments. In contrast, material stored within channels that was deposited during subsequent surges was predominantly channel-derived. The results demonstrate that fallout radionuclide tracers may provide unique information on the changing source contributions of fine sediment during debris flow events.

  3. Radionuclide release from PWR fuels in a reference tuff repository groundwater

    International Nuclear Information System (INIS)

    Wilson, C.N.; Oversby, V.M.

    1985-03-01

    The Nevada Nuclear Waste Storage Investigations Project (NNWSI) is studying the suitability of the welded devitrified Topopah Spring tuff at Yucca Mountain, Nye County, Nevada, for potential use as a high-level nuclear waste repository. In support of the Waste Package task of NNWSI, tests have been conducted under ambient air environment to measure radionuclide release from two pressurized water reactor (PWR) spent fuels in water obtained from the J-13 well near the Yucca Mountain site. Four specimen types, representing a range of fuel physical conditions that may exist in a failed waste canister containing a limited amount of water were tested. The specimen types were: fuel rod sections split open to expose bare fuel particles; rod sections with water-tight end fittings with a 2.5-cm long by 150-μm wide slit through the cladding; rod sections with water-tight end fittings and two 200-μm-diameter holes through the cladding; and undefected rod segments with water-tight end fittings. Radionuclide release results from the first 223-day test runs on H.B. Robinson spent fuel specimens in J-13 water are reported and compared to results from a previous test series in which similar Turkey Point reactor spent fuel specimens were tested on deionized water. Selected initial results are also given for Turkey Point fuel specimens tested on J-13 water. Results suggest that the actinides Pu, Am, Cm and Np are released congruently with U as the UO 2 spent fuel matrix dissolves. Fractional release of 137 Cs and 99 Tc was greater than that measured for the actinides. Generally, lower radionuclide releases were measured for the H.B. Robinson fuel in J-13 water than for Turkey Point Fuel in deionized water. 8 references, 7 figures, 9 tables

  4. GETOUT - a one-dimensional model for groundwater transport of radionuclide decay chains

    International Nuclear Information System (INIS)

    Grundfelt, B.; Elert, M.

    1980-01-01

    The GETOUT-code, originally developed at Batelle Pacific Northwest Laboratories (PNL), was used in the KBS-project to calculate the radionuclide discharges from the repository. The version used in KBS was a translation of the PNL BASIC-language version as by December 1976. In this report a new version, mathematically compatible with the PNL FORTRAN version as by 1979-08-15, is documented. Details are given on the differences between this new version and the version used in the KBS project up to now. (author)

  5. Gravity-driven groundwater flow and slope failure potential: 1. Elastic effective-stress model

    Science.gov (United States)

    Iverson, Richard M.; Reid, Mark E.

    1992-01-01

    Hilly or mountainous topography influences gravity-driven groundwater flow and the consequent distribution of effective stress in shallow subsurface environments. Effective stress, in turn, influences the potential for slope failure. To evaluate these influences, we formulate a two-dimensional, steady state, poroelastic model. The governing equations incorporate groundwater effects as body forces, and they demonstrate that spatially uniform pore pressure changes do not influence effective stresses. We implement the model using two finite element codes. As an illustrative case, we calculate the groundwater flow field, total body force field, and effective stress field in a straight, homogeneous hillslope. The total body force and effective stress fields show that groundwater flow can influence shear stresses as well as effective normal stresses. In most parts of the hillslope, groundwater flow significantly increases the Coulomb failure potential Φ, which we define as the ratio of maximum shear stress to mean effective normal stress. Groundwater flow also shifts the locus of greatest failure potential toward the slope toe. However, the effects of groundwater flow on failure potential are less pronounced than might be anticipated on the basis of a simpler, one-dimensional, limit equilibrium analysis. This is a consequence of continuity, compatibility, and boundary constraints on the two-dimensional flow and stress fields, and it points to important differences between our elastic continuum model and limit equilibrium models commonly used to assess slope stability.

  6. Effect of irrigation return flow on groundwater recharge in an overexploited aquifer in Bangladesh

    Science.gov (United States)

    Touhidul Mustafa, Syed Md.; Shamsudduha, Mohammad; Huysmans, Marijke

    2016-04-01

    Irrigated agriculture has an important role in the food production to ensure food security of Bangladesh that is home to over 150 million people. However, overexploitation of groundwater for irrigation, particularly during the dry season, causes groundwater-level decline in areas where abstraction is high and surface geology inhibits direct recharge to underlying shallow aquifer. This is causing a number of potential adverse socio-economic, hydrogeological, and environmental problems in Bangladesh. Alluvial aquifers are primarily recharged during monsoon season from rainfall and surface sources. However, return flow from groundwater-fed irrigation can recharge during the dry months. Quantification of the effect of return flow from irrigation in the groundwater system is currently unclear but thought to be important to ensure sustainable management of the overexploited aquifer. The objective of the study is to investigate the effect of irrigation return flow on groundwater recharge in the north-western part of Bangladesh, also known as Barind Tract. A semi-physically based distributed water balance model (WetSpass-M) is used to simulate spatially distributed monthly groundwater recharge. Results show that, groundwater abstraction for irrigation in the study area has increased steadily over the last 29 years. During the monsoon season, local precipitation is the controlling factor of groundwater recharge; however, there is no trend in groundwater recharge during that period. During the dry season, however, irrigation return-flow plays a major role in recharging the aquifer in the irrigated area compared to local precipitation. Therefore, during the dry season, mean seasonal groundwater recharge has increased and almost doubled over the last 29 years as a result of increased abstraction for irrigation. The increase in groundwater recharge during dry season has however no significant effect in the improvement of groundwater levels. The relation between groundwater

  7. The transfer of radionuclides from contaminated groundwater into perennial ryegrass and winter wheat

    International Nuclear Information System (INIS)

    Wadey, P.; Shaw, G.; Butler, A. P.; Tompkins, J. A.; Wheater, H. S.

    1996-01-01

    Lysimeter studies of the migration of radionuclides from a contaminated water table and their subsequent uptake by plant roots have been undertaken using two distinct soil types and varying crop regimes. An eight year multi-disciplinary research project (funded by Nirex) has concentrated on the upward migration of contaminants from near-surface water tables, and their uptake by winter wheat and perennial ryegrass crops. Experimental data are presented for the movement and uptake of radiocaesium 137 Cs. These data show significant movement in the unsaturated zone during the first year of dosing, followed by progressively reduced availability in subsequent years. A suite of physically based hydrological and solute transport models has been developed to model radionuclide transport in the unsaturated zone. Model simulations, based on a conventional advection-dispersion representation incorporating linear sorption processes, were unable to describe adequately the distribution of radiocaesium within the soil profile. However, the introduction of root storage and translocation processes provided significantly improved results. (author)

  8. Effect of Body Temperature on the Radionuclide Evaluation of Cerebral Blood Flow

    International Nuclear Information System (INIS)

    Mustafa, S. . E- mail: seham@hsc.edu.kw; Elgazzar, A.H.; Gopinath, S.; Mathew, M.; Khalil, M.

    2006-01-01

    Changes in regional cerebral blood flow (rCBF) may reflect physiological correlates of the disease state. In neuro-imaging studies, some diseases have frequently been reported to be associated with reduced or increased rCBF. In a previous study we had shown evidence of heat induced vasoconstriction of the carotid artery, which is the main vessel supplying blood to the brain. This vasoconstriction may lead to a decrease in cerebral blood flow in hyperthermic patients. Most radionuclide studies used to assess cerebral blood flow are routinely performed without taking into consideration patients' body temperature. In this regard it may be noted that results of radionuclide cerebral perfusion studies may be affected by hyperthermia, which could lead to false positive studies or misinterpretation of results when they are performed on patients suffering from various cerebrovascular diseases. The objective of the present study was to investigate the importance of body temperature and its effect on the results of radionuclide cerebral perfusion studies. Cerebral blood flow was assessed using Tc-99m hexamethylpropyleneamineoxime (Tc-99m HMPAO) imaging. Baseline scintigraphic images of the brain were obtained in 10 rabbits using a gamma camera equipped with a low energy parallel hole and high resolution collimator interfaced with a computer. Repeat brain studies were performed on the same rabbits at 3 and 6 days after raising the body temperature by 2 deg. C and 4 deg. C respectively using the same imaging protocol. The counts per pixel were determined on control and hyperthermia images. The uptake of Tc-99m HMPAO in the brain was found to be significantly reduced following hyperthermia implying reduction in blood flow. This decrease in cerebral perfusion appears to be variable from region to region, being more in the cerebral hemispheres, frontal areas (olfactory lobes) than in the cerebellum. Based on the results, the authors conclude that a rise in body temperature might

  9. Measurement of radionuclides using ion chromatography and flow-cell scintillation counting with pulse shape discrimination

    International Nuclear Information System (INIS)

    DeVol, T.A.; Fjeld, R.A.

    1995-01-01

    A project has been initiated at Clemson Univ. to develop a HPLC/flow- cell system for analysis of non-gamma emitting radionuclides in environmental samples; an important component is development of a low background flow-cell detector that counts alpha and beta particles separately through pulse shape discrimination. Objective of the work presented here is to provide preliminary results of an evaluation of the following scintillators: CaF 2 :Eu, scintillating glass, and BaF 2 . Slightly acidic aqueous solutions of the alpha emitter 233 U and the beta emitter 45 Ca were used. Detection efficiencies and minimum detectable activities were determined

  10. Groundwater flow modeling in construction phase of the Mizunami Underground Research Laboratory project

    International Nuclear Information System (INIS)

    Onoe, Hironori; Saegusa, Hiromitsu; Takeuchi, Ryuji

    2016-01-01

    This paper comprehensively describes the result of groundwater flow modeling using data of hydraulic responses due to construction of Mizunami Underground Research Laboratory (MIU) in Mizunami, Gifu, in order to update hydrogeological model based on stepwise approach for crystalline fractured rock in Japan. The results showed that large scale hydraulic compartment structures which has significant influence on change of groundwater flow characteristics are distributed around MIU. Furthermore, it is concluded that hydrogeological monitoring data and groundwater flow modeling during construction of deep underground facilities are effective for hydrogeological characterization of heterogeneous fractured rock. (author)

  11. Structural Control and Groundwater Flow in the Nubian Aquifer

    Science.gov (United States)

    Fathy, K.; Sultan, M.; Ahmed, M.; Save, H.; Emil, M. K.; Elkaliouby, B.

    2017-12-01

    An integrated research approach (remote sensing, field, geophysics) was conducted to investigate the structural control on groundwater flow in large aquifers using the less studied Nubian Sandstone Aquifer System (NSAS) of NE Africa as a test site. The aquifer extends over 2.2 x 106 km2 in Egypt, Libya, Chad, and Sudan and consists of thick (> 3 kms), water-bearing, Paleozoic and Mesozoic sandstone with intercalations of Tertiary shale and clay. It is subdivided into three sub-basins (Northern Sudan Platform [NSP], Dakhla [DAS], and Kufra) that are separated by basement uplifts (e.g., E-W trending Uweinat-Aswan uplift that separates DAS from the NSP). Aquifer recharge occurs in the south (NSP and southern Kufra) where the aquifer is unconfined and precipitation is high (Average Annual Precipitation [AAP]: 117 mm/yr.) and discharge is concentrated in the north (DAS and northern Kufra). Our approach is a three-fold exercise. Firstly, we compared GOCE-based Global Geopotential Models (GGMs) to terrestrial gravity anomalies for 21262 sites to select the optimum model for deriving Bouguer gravity anomalies. Secondly, structures and uplifts were mapped using hill shade images and their extension in the subsurface were mapped using the Eigen_6C4 model-derived Bouguer anomalies and their Tilt Derivative products (TDR). Thirdly, hydrological analysis was conducted using GRACE CSR 1° x 1° mascon solutions to investigate the mass variations in relation to the mapped structures. Our findings include: (1) The Eigen-6C4 is the optimum model having the lowest deviation (9.122 mGal) from the terrestrial gravity anomalies; (2) the surface expressions of structures matched fairly well with their postulated extensions in the subsurface; (3) identified fault systems include: Red Sea rift-related N-S to NW-SE trending grabens formed by reactivating basement structures during Red Sea opening and Syrian arc-related NE-SW trending dextral shear systems; (4) TWS patterns are uniform

  12. Groundwater flow system under a rapidly urbanizing coastal city as determined by hydrogeochemistry

    Science.gov (United States)

    Kagabu, Makoto; Shimada, Jun; Delinom, Robert; Tsujimura, Maki; Taniguchi, Makoto

    2011-01-01

    In the Jakarta area (Indonesia), excessive groundwater pumping due to the rapidly increasing population has caused groundwater-related problems such as brackish water contamination in coastal areas and land subsidence. In this study, we adopted multiple hydrogeochemical techniques to demonstrate the groundwater flow system in the Jakarta area. Although almost all groundwater existing in the Jakarta basin is recharged at similar elevations, the water quality and residence time demonstrates a clear difference between the shallow and deep aquifers. Due to the rapid decrease in the groundwater potential in urban areas, we found that the seawater intrusion and the shallow and deep groundwaters are mixing, a conclusion confirmed by major ions, Br -:Cl - ratios, and chlorofluorocarbon (CFC)-12 analysis. Spring water and groundwater samples collected from the southern mountainside area show younger age characteristics with high concentrations of 14C and Ca-HCO 3 type water chemistry. We estimated the residence times of these groundwaters within 45 years under piston flow conditions by tritium analysis. Also, these groundwater ages can be limited to 20-30 years with piston flow evaluated by CFCs. Moreover, due to the magnitude of the CFC-12 concentration, we can use a pseudo age indicator in this field study, because we found a positive correlation between the major type of water chemistry and the CFC-12 concentration.

  13. Implications of groundwater weathered profile interactions to the mobilization of radionuclides

    International Nuclear Information System (INIS)

    Bonotto, D.M.

    1994-01-01

    Full text: This study reports the nature and extent of open-system interaction between groundwater and a weathered profile developed in the high grade thorium and rare earth elements ore body in Morro do Ferro, Pocos de Caldas plateau. The radioelement mobility in the shallow oxidizing environment was considered on using chemical data in conjunction with U-234/U-238, Th-228/Th-232, Ra-226/Th-230 and Th-230/U-234 activity rations for borehole spoil and groundwater samples. Recharging groundwater from the studied borehole has low salinity values, with total dissolved solids content of 14.7 mg/l and total ionic strength of 0.00018. The ratio of the weight of dissolved radioelement per unit volume of solution to the weight of radioelement in solid phase per unit weight of solid phase showed that the radioelement solubility in the studied waters varied according to the following order: radium >> uranium > thorium. U-234/U-238 activity rations less than 1 were measured in solid phase and can justify the enhancement of U-234 in solution. Th-228/Th-232 activity ratio greater than 1 was found at about 18.75 m depth and is related with ingrowth of Th-228 from Ra-228 held in this site. Ra-226/Th-230 activity ratios greater than 1 and Th-230/U-234 activity ratios less than were evaluated between 20 and 27 m depth, where a 2.1-m thick magnetite dike was intersected. These ratios could be justified by deposition of U and Ra associated with ferric oxyhydroxides and kaolinite. Typical adsorption coefficient values for these phases and minerals saturation indices evaluated from the available data confirm this possibility

  14. Using 14C and 3H to understand groundwater flow and recharge in an aquifer window

    Science.gov (United States)

    Atkinson, A. P.; Cartwright, I.; Gilfedder, B. S.; Cendón, D. I.; Unland, N. P.; Hofmann, H.

    2014-12-01

    Knowledge of groundwater residence times and recharge locations is vital to the sustainable management of groundwater resources. Here we investigate groundwater residence times and patterns of recharge in the Gellibrand Valley, southeast Australia, where outcropping aquifer sediments of the Eastern View Formation form an "aquifer window" that may receive diffuse recharge from rainfall and recharge from the Gellibrand River. To determine recharge patterns and groundwater flow paths, environmental isotopes (3H, 14C, δ13C, δ18O, δ2H) are used in conjunction with groundwater geochemistry and continuous monitoring of groundwater elevation and electrical conductivity. The water table fluctuates by 0.9 to 3.7 m annually, implying recharge rates of 90 and 372 mm yr-1. However, residence times of shallow (11 to 29 m) groundwater determined by 14C are between 100 and 10 000 years, 3H activities are negligible in most of the groundwater, and groundwater electrical conductivity remains constant over the period of study. Deeper groundwater with older 14C ages has lower δ18O values than younger, shallower groundwater, which is consistent with it being derived from greater altitudes. The combined geochemistry data indicate that local recharge from precipitation within the valley occurs through the aquifer window, however much of the groundwater in the Gellibrand Valley predominantly originates from the regional recharge zone, the Barongarook High. The Gellibrand Valley is a regional discharge zone with upward head gradients that limits local recharge to the upper 10 m of the aquifer. Additionally, the groundwater head gradients adjacent to the Gellibrand River are generally upwards, implying that it does not recharge the surrounding groundwater and has limited bank storage. 14C ages and Cl concentrations are well correlated and Cl concentrations may be used to provide a first-order estimate of groundwater residence times. Progressively lower chloride concentrations from 10

  15. Groundwater flow modeling focused on the Fukushima Daiichi Nuclear Power Plant Site

    International Nuclear Information System (INIS)

    Saegusa, Hiromitsu; Onoe, Hironori; Kohashi, Akio; Watanabe, Masahisa

    2015-01-01

    Fukushima Daiichi nuclear power plant of Tokyo Electric Power Company is facing contaminated water issues in the aftermath of the Great East Japan Earthquake on March 11, 2011. The amount of contaminated water is continuously increasing due to groundwater leakage into the underground part of reactor and turbine buildings. Therefore, it is important to understand the groundwater flow conditions at the site and to predict the impact of countermeasures taken for isolating groundwater from the source of the contamination, i.e. the reactor buildings. Installations, such as of land-side and sea-side impermeable walls have been planned as countermeasures. In this study, groundwater flow modeling has been performed to estimate the response of groundwater flow conditions to the countermeasures. From the modeling, groundwater recharge and discharge areas, major groundwater flow direction, inflow rate into underground part of the buildings, and changes in response to implementation of the countermeasures could be reasonably estimated. The results indicate that the countermeasures will decrease the volume of inflow into the underground part of the buildings. This means that the countermeasures will be effective in reducing the discharge volume of contaminated groundwater to ocean. (author)

  16. Groundwater flow and hydrogeochemical evolution in the Jianghan Plain, central China

    Science.gov (United States)

    Gan, Yiqun; Zhao, Ke; Deng, Yamin; Liang, Xing; Ma, Teng; Wang, Yanxin

    2018-05-01

    Hydrogeochemical analysis and multivariate statistics were applied to identify flow patterns and major processes controlling the hydrogeochemistry of groundwater in the Jianghan Plain, which is located in central Yangtze River Basin (central China) and characterized by intensive surface-water/groundwater interaction. Although HCO3-Ca-(Mg) type water predominated in the study area, the 457 (21 surface water and 436 groundwater) samples were effectively classified into five clusters by hierarchical cluster analysis. The hydrochemical variations among these clusters were governed by three factors from factor analysis. Major components (e.g., Ca, Mg and HCO3) in surface water and groundwater originated from carbonate and silicate weathering (factor 1). Redox conditions (factor 2) influenced the geogenic Fe and As contamination in shallow confined groundwater. Anthropogenic activities (factor 3) primarily caused high levels of Cl and SO4 in surface water and phreatic groundwater. Furthermore, the factor score 1 of samples in the shallow confined aquifer gradually increased along the flow paths. This study demonstrates that enhanced information on hydrochemistry in complex groundwater flow systems, by multivariate statistical methods, improves the understanding of groundwater flow and hydrogeochemical evolution due to natural and anthropogenic impacts.

  17. Validation, Proof-of-Concept, and Postaudit of the Groundwater Flow and Transport Model of the Project Shoal Area

    International Nuclear Information System (INIS)

    Ahmed Hassan

    2004-01-01

    The groundwater flow and radionuclide transport model characterizing the Shoal underground nuclear test has been accepted by the State of Nevada Division of Environmental Protection. According to the Federal Facility Agreement and Consent Order (FFACO) between DOE and the State of Nevada, the next steps in the closure process for the site are then model validation (or postaudit), the proof-of-concept, and the long-term monitoring stage. This report addresses the development of the validation strategy for the Shoal model, needed for preparing the subsurface Corrective Action Decision Document-Corrective Action Plan and the development of the proof-of-concept tools needed during the five-year monitoring/validation period. The approach builds on a previous model, but is adapted and modified to the site-specific conditions and challenges of the Shoal site

  18. Validation, Proof-of-Concept, and Postaudit of the Groundwater Flow and Transport Model of the Project Shoal Area

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed Hassan

    2004-09-01

    The groundwater flow and radionuclide transport model characterizing the Shoal underground nuclear test has been accepted by the State of Nevada Division of Environmental Protection. According to the Federal Facility Agreement and Consent Order (FFACO) between DOE and the State of Nevada, the next steps in the closure process for the site are then model validation (or postaudit), the proof-of-concept, and the long-term monitoring stage. This report addresses the development of the validation strategy for the Shoal model, needed for preparing the subsurface Corrective Action Decision Document-Corrective Action Plan and the development of the proof-of-concept tools needed during the five-year monitoring/validation period. The approach builds on a previous model, but is adapted and modified to the site-specific conditions and challenges of the Shoal site.

  19. Stable isotope and groundwater flow dynamics of agricultural irrigation recharge into groundwater resources of the Central Valley, California

    International Nuclear Information System (INIS)

    Davisson, M.L.; Criss, R.E.

    1995-01-01

    Intensive agricultural irrigation and overdraft of groundwater in the Central Valley of California profoundly affect the regional quality and availability of shallow groundwater resources. In the natural state, the δ 18 O values of groundwater were relatively homogeneous (mostly -7.0 ± 0.5 per-thousand), reflecting local meteoric recharge that slowly (1-3m/yr) flowed toward the valley axis. Today, on the west side of the valley, the isotope distribution is dominated by high 18 O enclosures formed by recharge of evaporated irrigation waters, while the east side has bands of low 18 O groundwater indicating induced recharge from rivers draining the Sierra Nevada mountains. Changes in δ 18 O values caused by the agricultural recharge strongly correlate with elevated nitrate concentrations (5 to >100 mg/L) that form pervasive, non-point source pollutants. Small, west-side cities dependent solely on groundwater resources have experienced increases of >1.0 mg/L per year of nitrate for 10-30 years. The resultant high nitrates threaten the economical use of the groundwater for domestic purposes, and have forced some well shut-downs. Furthermore, since >80% of modern recharge is now derived from agricultural irrigation, and because modern recharge rates are ∼10 times those of the natural state, agricultural land retirement by urbanization will severely curtail the current safe-yields and promote overdraft pumping. Such overdrafting has occurred in the Sacramento metropolitan area for ∼40 years, creating cones of depression ∼25m deep. Today, groundwater withdrawal in Sacramento is approximately matched by infiltration of low 18 O water (-11.0 per-thousand) away from the Sacramento and American Rivers, which is estimated to occur at 100-300m/year from the sharp 18 O gradients in our groundwater isotope map

  20. Groundwater flow through a natural fracture. Flow experiments and numerical modelling

    Energy Technology Data Exchange (ETDEWEB)

    Larsson, Erik [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept of Geology

    1997-09-01

    Groundwater flow and transport play an important role not only for groundwater exploration but also in environmental engineering problems. This report considers how the hydraulic properties of fractures in crystalline rock depend on the fracture aperture geometry. Different numerical models are discussed and a FDM computer code for two- and three- dimensional flow-modelling has been developed. Different relations between the cells in the model are tested and compared with results in the literature. A laboratory experimental work has been done to carry out flow experiments and aperture measurements on the same specimen of a natural fracture. The drilled core sample had fractures parallel to the core axis and was placed inside a biaxial cell during the experiments. The water pressure gradient and the compression stress were varied during the experiments and also a tracer test was done. After the flow experiments, the aperture distribution for a certain compression was measured by injecting an epoxy resin into the fracture. The thickness of the resin layer was then studied in saw cut sections of the sample. The results from the experiments were used to validate numerical and analytical models, based on aperture distribution, for flow and transport simulations. In the disturbed zone around a drift both water and air are present in the fractures. The gas will go to the most wide part of the fracture because the capillarity and the conductivity decrease. The dependence of the effective conductivity on the variance of the conductivity and the effect of extinction of highly conductive cells has also been studied. A discussion of how gas in fractures around a drift can cause a skin effect is modelled and an example is given of what a saturation depending on the magnitude of the flow causes. 25 refs, 17 tabs, 43 figs.

  1. Groundwater flow through a natural fracture. Flow experiments and numerical modelling

    International Nuclear Information System (INIS)

    Larsson, Erik

    1997-09-01

    Groundwater flow and transport play an important role not only for groundwater exploration but also in environmental engineering problems. This report considers how the hydraulic properties of fractures in crystalline rock depend on the fracture aperture geometry. Different numerical models are discussed and a FDM computer code for two- and three- dimensional flow-modelling has been developed. Different relations between the cells in the model are tested and compared with results in the literature. A laboratory experimental work has been done to carry out flow experiments and aperture measurements on the same specimen of a natural fracture. The drilled core sample had fractures parallel to the core axis and was placed inside a biaxial cell during the experiments. The water pressure gradient and the compression stress were varied during the experiments and also a tracer test was done. After the flow experiments, the aperture distribution for a certain compression was measured by injecting an epoxy resin into the fracture. The thickness of the resin layer was then studied in saw cut sections of the sample. The results from the experiments were used to validate numerical and analytical models, based on aperture distribution, for flow and transport simulations. In the disturbed zone around a drift both water and air are present in the fractures. The gas will go to the most wide part of the fracture because the capillarity and the conductivity decrease. The dependence of the effective conductivity on the variance of the conductivity and the effect of extinction of highly conductive cells has also been studied. A discussion of how gas in fractures around a drift can cause a skin effect is modelled and an example is given of what a saturation depending on the magnitude of the flow causes

  2. Site-scale groundwater flow modelling of Beberg

    Energy Technology Data Exchange (ETDEWEB)

    Gylling, B. [Kemakta Konsult AB, Stockholm (Sweden); Walker, D. [Duke Engineering and Services (United States); Hartley, L. [AEA Technology, Harwell (United Kingdom)

    1999-08-01

    The Swedish Nuclear Fuel and Waste Management Company (SKB) Safety Report for 1997 (SR 97) study is a comprehensive performance assessment illustrating the results for three hypothetical repositories in Sweden. In support of SR 97, this study examines the hydrogeologic modelling of the hypothetical site called Beberg, which adopts input parameters from the SKB study site near Finnsjoen, in central Sweden. This study uses a nested modelling approach, with a deterministic regional model providing boundary conditions to a site-scale stochastic continuum model. The model is run in Monte Carlo fashion to propagate the variability of the hydraulic conductivity to the advective travel paths from representative canister positions. A series of variant cases addresses uncertainties in the inference of parameters and the boundary conditions. The study uses HYDRASTAR, the SKB stochastic continuum (SC) groundwater modelling program, to compute the heads, Darcy velocities at each representative canister position, and the advective travel times and paths through the geosphere. The Base Case simulation takes its constant head boundary conditions from a modified version of the deterministic regional scale model of Hartley et al. The flow balance between the regional and site-scale models suggests that the nested modelling conserves mass only in a general sense, and that the upscaling is only approximately valid. The results for 100 realisation of 120 starting positions, a flow porosity of {epsilon}{sub f} 10{sup -4}, and a flow-wetted surface of a{sub r} = 1.0 m{sup 2}/(m{sup 3} rock) suggest the following statistics for the Base Case: The median travel time is 56 years. The median canister flux is 1.2 x 10{sup -3} m/year. The median F-ratio is 5.6 x 10{sup 5} year/m. The travel times, flow paths and exit locations were compatible with the observations on site, approximate scoping calculations and the results of related modelling studies. Variability within realisations indicates

  3. Site-scale groundwater flow modelling of Beberg

    International Nuclear Information System (INIS)

    Gylling, B.; Walker, D.; Hartley, L.

    1999-08-01

    The Swedish Nuclear Fuel and Waste Management Company (SKB) Safety Report for 1997 (SR 97) study is a comprehensive performance assessment illustrating the results for three hypothetical repositories in Sweden. In support of SR 97, this study examines the hydrogeologic modelling of the hypothetical site called Beberg, which adopts input parameters from the SKB study site near Finnsjoen, in central Sweden. This study uses a nested modelling approach, with a deterministic regional model providing boundary conditions to a site-scale stochastic continuum model. The model is run in Monte Carlo fashion to propagate the variability of the hydraulic conductivity to the advective travel paths from representative canister positions. A series of variant cases addresses uncertainties in the inference of parameters and the boundary conditions. The study uses HYDRASTAR, the SKB stochastic continuum (SC) groundwater modelling program, to compute the heads, Darcy velocities at each representative canister position, and the advective travel times and paths through the geosphere. The Base Case simulation takes its constant head boundary conditions from a modified version of the deterministic regional scale model of Hartley et al. The flow balance between the regional and site-scale models suggests that the nested modelling conserves mass only in a general sense, and that the upscaling is only approximately valid. The results for 100 realisation of 120 starting positions, a flow porosity of ε f 10 -4 , and a flow-wetted surface of a r = 1.0 m 2 /(m 3 rock) suggest the following statistics for the Base Case: The median travel time is 56 years. The median canister flux is 1.2 x 10 -3 m/year. The median F-ratio is 5.6 x 10 5 year/m. The travel times, flow paths and exit locations were compatible with the observations on site, approximate scoping calculations and the results of related modelling studies. Variability within realisations indicates that the change in hydraulic gradient

  4. Simulation of ground-water flow and land subsidence in the Antelope Valley ground-water basin, California

    Science.gov (United States)

    Leighton, David A.; Phillips, Steven P.

    2003-01-01

    Antelope Valley, California, is a topographically closed basin in the western part of the Mojave Desert, about 50 miles northeast of Los Angeles. The Antelope Valley ground-water basin is about 940 square miles and is separated from the northern part of Antelope Valley by faults and low-lying hills. Prior to 1972, ground water provided more than 90 percent of the total water supply in the valley; since 1972, it has provided between 50 and 90 percent. Most ground-water pumping in the valley occurs in the Antelope Valley ground-water basin, which includes the rapidly growing cities of Lancaster and Palmdale. Ground-water-level declines of more than 200 feet in some parts of the ground-water basin have resulted in an increase in pumping lifts, reduced well efficiency, and land subsidence of more than 6 feet in some areas. Future urban growth and limits on the supply of imported water may continue to increase reliance on ground water. To better understand the ground-water flow system and to develop a tool to aid in effectively managing the water resources, a numerical model of ground-water flow and land subsidence in the Antelope Valley ground-water basin was developed using old and new geohydrologic information. The ground-water flow system consists of three aquifers: the upper, middle, and lower aquifers. The aquifers, which were identified on the basis of the hydrologic properties, age, and depth of the unconsolidated deposits, consist of gravel, sand, silt, and clay alluvial deposits and clay and silty clay lacustrine deposits. Prior to ground-water development in the valley, recharge was primarily the infiltration of runoff from the surrounding mountains. Ground water flowed from the recharge areas to discharge areas around the playas where it discharged either from the aquifer system as evapotranspiration or from springs. Partial barriers to horizontal ground-water flow, such as faults, have been identified in the ground-water basin. Water-level declines owing to

  5. Controls on groundwater flow in the Bengal Basin of India and Bangladesh: regional modeling analysis

    Science.gov (United States)

    Michael, Holly A.; Voss, Clifford I.

    2009-11-01

    Groundwater for domestic and irrigation purposes is produced primarily from shallow parts of the Bengal Basin aquifer system (India and Bangladesh), which contains high concentrations of dissolved arsenic (exceeding worldwide drinking water standards), though deeper groundwater is generally low in arsenic. An essential first step for determining sustainable management of the deep groundwater resource is identification of hydrogeologic controls on flow and quantification of basin-scale groundwater flow patterns. Results from groundwater modeling, in which the Bengal Basin aquifer system is represented as a single aquifer with higher horizontal than vertical hydraulic conductivity, indicate that this anisotropy is the primary hydrogeologic control on the natural flowpath lengths. Despite extremely low hydraulic gradients due to minimal topographic relief, anisotropy implies large-scale (tens to hundreds of kilometers) flow at depth. Other hydrogeologic factors, including lateral and vertical changes in hydraulic conductivity, have minor effects on overall flow patterns. However, because natural hydraulic gradients are low, the impact of pumping on groundwater flow is overwhelming; modeling indicates that pumping has substantially changed the shallow groundwater budget and flowpaths from predevelopment conditions.

  6. Arrangement of disposal holes according to the features of groundwater flow

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Nak Youl; Baik, Min Hoon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-12-15

    Based on the results of groundwater flow system modeling for a hypothetical deep geological repository site, quantitative and spatial distributions of groundwater flow rates at the positions of deposition holes, groundwater travel length and time from the positions to the surface environment were analyzed and used to suggest a method for determining locations of deposition holes. The hydraulic head values at the depth of the deposition holes and a particle tracking method were used to calculate the groundwater flow rates and groundwater travel length and time, respectively. From the results, an approach to designing a layout of deposition holes was suggested by selecting relatively favorable positions for maintaining performance of the disposal facility and screening some positions of deposition holes that did not comply with specific constraints for the groundwater flow rates, travel length and time. In addition, a method for determining a geometrical direction for extension of the disposal facility was discussed. Designing the layout of deposition holes with the information of groundwater flow at the disposal depth can contribute to secure performance and safety of the disposal facility.

  7. Controls on groundwater flow in the Bengal Basin of India and Bangladesh: Regional modeling analysis

    Science.gov (United States)

    Michael, H.A.; Voss, C.I.

    2009-01-01

    Groundwater for domestic and irrigation purposes is produced primarily from shallow parts of the Bengal Basin aquifer system (India and Bangladesh), which contains high concentrations of dissolved arsenic (exceeding worldwide drinking water standards), though deeper groundwater is generally low in arsenic. An essential first step for determining sustainable management of the deep groundwater resource is identification of hydrogeologic controls on flow and quantification of basin-scale groundwater flow patterns. Results from groundwater modeling, in which the Bengal Basin aquifer system is represented as a single aquifer with higher horizontal than vertical hydraulic conductivity, indicate that this anisotropy is the primary hydrogeologic control on the natural flowpath lengths. Despite extremely low hydraulic gradients due to minimal topographic relief, anisotropy implies large-scale (tens to hundreds of kilometers) flow at depth. Other hydrogeologic factors, including lateral and vertical changes in hydraulic conductivity, have minor effects on overall flow patterns. However, because natural hydraulic gradients are low, the impact of pumping on groundwater flow is overwhelming; modeling indicates that pumping has substantially changed the shallow groundwater budget and flowpaths from predevelopment conditions. ?? Springer-Verlag 2009.

  8. Using Flux Information at Surface Water Boundaries to Improve a Groundwater Flow and Transport Model

    National Research Council Canada - National Science Library

    Genereux, David

    2000-01-01

    We investigated the performance of a groundwater flow and solute transport model when different combinations of hydraulic head, seepage flux, and chloride concentration data were used in calibration of the model...

  9. Important radionuclides and their sensitivity for groundwater pathway of a hypothetical near-surface disposal facility

    Energy Technology Data Exchange (ETDEWEB)

    Park, J. W.; Chang, K.; Kim, C. L. [Nuclear Enviroment Technology Institute, Taejon (Korea, Republic of)

    2001-04-01

    A radiological safety assessment was performed for a hypothetical near-surface radioactive waste repository as a simple screening calculation to identify important nuclides and to provide insights on the data needs for a successful demonstration of compliance. Individual effective doses were calculated for a conservative groundwater pathway scenario considering well drilling near the site boundary. Sensitivity of resulting ingestion dose to input parameter values was also analyzed using Monte Carlo sampling. Considering peak dose rate and assessment timescale, C-14 and I-129 were identified as important nuclides and U-235 and U-238 as potentially important nuclides. For C-14, the does was most sensitive to Darcy velocity in aquifer. The distribution coefficient showed high degree of sensitivity for I-129 release.

  10. Important radionuclides and their sensitivity for groundwater pathway of a hypothetical near-surface disposal facility

    International Nuclear Information System (INIS)

    Park, J. W.; Chang, K.; Kim, C. L.

    2001-01-01

    A radiological safety assessment was performed for a hypothetical near-surface radioactive waste repository as a simple screening calculation to identify important nuclides and to provide insights on the data needs for a successful demonstration of compliance. Individual effective doses were calculated for a conservative groundwater pathway scenario considering well drilling near the site boundary. Sensitivity of resulting ingestion dose to input parameter values was also analyzed using Monte Carlo sampling. Considering peak dose rate and assessment timescale, C-14 and I-129 were identified as important nuclides and U-235 and U-238 as potentially important nuclides. For C-14, the does was most sensitive to Darcy velocity in aquifer. The distribution coefficient showed high degree of sensitivity for I-129 release

  11. Underwater in situ measurements of radionuclides in selected submarine groundwater springs, Mediterranean sea

    International Nuclear Information System (INIS)

    Tsabaris, C.; Scholten, J.; Karageorgis, A. P.; Comanducci, J. F.; Georgopoulos, D.; Liong Wee Kwong, L.; Patiris, D. L.; Papathanassiou, E.

    2010-01-01

    The application of the in situ measurement system 'KATERINA' for monitoring of radon progenies in submarine groundwater discharge (SGD) was investigated at different locations in the Mediterranean Sea (Chalkida, Stoupa, Korfos and Cabbe). At Chalkida and Stoupa radon progenies concentration exhibited almost constant values of 1.2±0.1 and 2.5±0.2 Bq l -1 , respectively. At Korfos these activities ranged between 1.4±0.1 and 2.3±0.2 Bq l -1 exhibiting inverse relationship with salinity. At Cabbe the in situ measured data were compared with radon measurements obtained by liquid scintillation counter. The system also resolved radon progeny variations of SGD on time scales above 1 h. The radioactivity levels of radon progenies from all sites were found considerably lower (approximately 2 orders of magnitude) than the commonly accepted limits for radon in drinking water. (authors)

  12. Simulation of groundwater flow and interaction of groundwater and surface water on the Lac du Flambeau Reservation, Wisconsin

    Science.gov (United States)

    Juckem, Paul F.; Fienen, Michael N.; Hunt, Randall J.

    2014-01-01

    The Lac du Flambeau Band of Lake Superior Chippewa and Indian Health Service are interested in improving the understanding of groundwater flow and groundwater/surface-water interaction on the Lac du Flambeau Reservation (Reservation) in southwest Vilas County and southeast Iron County, Wisconsin, with particular interest in an understanding of the potential for contamination of groundwater supply wells and the fate of wastewater that is infiltrated from treatment lagoons on the Reservation. This report describes the construction, calibration, and application of a regional groundwater flow model used to simulate the shallow groundwater flow system of the Reservation and water-quality results for groundwater and surface-water samples collected near a system of waste-water-treatment lagoons. Groundwater flows through a permeable glacial aquifer that ranges in thickness from 60 to more than 200 feet (ft). Seepage and drainage lakes are common in the area and influence groundwater flow patterns on the Reservation. A two-dimensional, steady-state analytic element groundwater flow model was constructed using the program GFLOW. The model was calibrated by matching target water levels and stream base flows through the use of the parameter-estimation program, PEST. Simulated results illustrate that groundwater flow within most of the Reservation is toward the Bear River and the chain of lakes that feed the Bear River. Results of analyses of groundwater and surface-water samples collected downgradient from the wastewater infiltration lagoons show elevated levels of ammonia and dissolved phosphorus. In addition, wastewater indicator chemicals detected in three downgradient wells and a small downgradient stream indicate that infiltrated wastewater is moving southwest of the lagoons toward Moss Lake. Potential effects of extended wet and dry periods (within historical ranges) were evaluated by adjusting precipitation and groundwater recharge in the model and comparing the

  13. Radionuclides in shallow groundwater at Solid Waste Storage Area 5 North, Oak Ridge National Laboratory

    International Nuclear Information System (INIS)

    Ashwood, T.L.; Marsh, J.D. Jr.

    1994-04-01

    This report presents a compilation of groundwater monitoring data from Solid Waste Storage Area (SWSA) 5 North at Oak Ridge National Laboratory (ORNL) between November 1989 and September 1993. Monitoring data were collected as part of the Active Sites Environmental Monitoring Program that was implemented in 1989 in response to DOE Order 5820.2A. SWSA 5 North was established for the retrievable storage of transuranic (TRU) wastes in 1970. Four types of storage have been used within SWSA 5 North: bunkers, vaults, wells, and trenches. The fenced portion of SWSA 5 North covers about 3.7 ha (9 acres) in the White Oak Creek watershed south of ORNL. The area is bounded by White Oak Creek and two ephemeral tributaries of White Oak Creek. Since 1989, groundwater has been monitored in wells around SWSA 5 North. During that time, elevated gross alpha contamination (reaching as high as 210 Bq/L) has consistently been detected in well 516. This well is adjacent to burial trenches in the southwest corner of the area. Water level measurements in wells 516 and 518 suggest that water periodically inundates the bottom of some of those trenches. Virtually all of the gross alpha contamination is generated by Curium 244 and Americium 241. A special geochemical investigation of well 516 suggests that nearly all of the Curium 44 and Americium 241 is dissolved or associated with dissolved organic matter. These are being transported at the rate of about 2 m/year from the burial trenches, through well 516, to White Oak Creek, where Curium 244 has been detected in a few bank seeps. Concentrations at these seeps are near detection levels (<1 Bq/L)

  14. Radionuclides in shallow groundwater at Solid Waste Storage Area 5 North, Oak Ridge National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Ashwood, T.L.; Marsh, J.D. Jr.

    1994-04-01

    This report presents a compilation of groundwater monitoring data from Solid Waste Storage Area (SWSA) 5 North at Oak Ridge National Laboratory (ORNL) between November 1989 and September 1993. Monitoring data were collected as part of the Active Sites Environmental Monitoring Program that was implemented in 1989 in response to DOE Order 5820.2A. SWSA 5 North was established for the retrievable storage of transuranic (TRU) wastes in 1970. Four types of storage have been used within SWSA 5 North: bunkers, vaults, wells, and trenches. The fenced portion of SWSA 5 North covers about 3.7 ha (9 acres) in the White Oak Creek watershed south of ORNL. The area is bounded by White Oak Creek and two ephemeral tributaries of White Oak Creek. Since 1989, groundwater has been monitored in wells around SWSA 5 North. During that time, elevated gross alpha contamination (reaching as high as 210 Bq/L) has consistently been detected in well 516. This well is adjacent to burial trenches in the southwest corner of the area. Water level measurements in wells 516 and 518 suggest that water periodically inundates the bottom of some of those trenches. Virtually all of the gross alpha contamination is generated by Curium 244 and Americium 241. A special geochemical investigation of well 516 suggests that nearly all of the Curium 44 and Americium 241 is dissolved or associated with dissolved organic matter. These are being transported at the rate of about 2 m/year from the burial trenches, through well 516, to White Oak Creek, where Curium 244 has been detected in a few bank seeps. Concentrations at these seeps are near detection levels (<1 Bq/L).

  15. Comparing groundwater recharge and base flow in the Bukmoongol ...

    Indian Academy of Sciences (India)

    Groundwater recharge and base flow using different investigated methods are simulated in the 15-ha Bukmoongol small-forested watershed located at the southern part of Korea.The WHAT system, PART,RORA,PULSE,BFI,and RAP software are used to estimate groundwater recharge or base flow and base flow index from ...

  16. The in situ permeable flow sensor: A device for measuring groundwater flow velocity

    International Nuclear Information System (INIS)

    Ballard, S.; Barker, G.T.; Nichols, R.L.

    1994-03-01

    A new technology called the In Situ Permeable Flow Sensor has been developed at Sandia National Laboratories. These sensors use a thermal perturbation technique to directly measure the direction and magnitude of the full three dimensional groundwater flow velocity vector in unconsolidated, saturated, porous media. The velocity measured is an average value characteristic of an approximately 1 cubic meter volume of the subsurface. During a test at the Savannah River Site in South Carolina, two flow sensors were deployed in a confined aquifer in close proximity to a well which was screened over the entire vertical extent of the aquifer and the well was pumped at four different pumping rates. In this situation horizontal flow which is radially directed toward the pumping well is expected. The flow sensors measured horizontal flow which was directed toward the pumping well, within the uncertainty in the measurements. The observed magnitude of the horizontal component of the flow velocity increased linearly with pumping rate, as predicted by theoretical considerations. The measured horizontal component of the flow velocity differed from the predicted flow velocity, which was calculated with the assumptions that the hydraulic properties of the aquifer were radially homogeneous and isotropic, by less than a factor of two. Drawdown data obtained from other wells near the pumping well during the pump test indicate that the hydraulic properties of the aquifer are probably not radially homogeneous but the effect of the inhomogeneity on the flow velocity field around the pumping well was not modeled because the degree and distribution of the inhomogeneity are unknown. Grain size analysis of core samples from wells in the area were used to estimate the vertical distribution of hydraulic conductivity

  17. Wairarapa Valley groundwater : residence time, flow pattern, and hydrochemistry trends

    International Nuclear Information System (INIS)

    Morgenstern, U.

    2005-01-01

    The Wairarapa groundwater system has a complicated hydrogeological setting as it evolved from sea level changes, tectonic activity, and geomorphic process. Due to increasing groundwater demand a better understanding of the groundwater resources is required to help achieve effective management and sustainable use. In addition to previous 'classical' hydrogeology studies, this report represents the first stage of a comprehensive approach using age dating and chemistry time trends for understanding the Wairarapa groundwater system. The methodology of groundwater age dating and mixing models is described in Appendix 1. Historic tritium data were evaluated, and combined with new tritium and CFC/SF 6 data to allow for robust age dating. (author). 14 refs., 30 figs

  18. Radionuclide migration in geological formations

    International Nuclear Information System (INIS)

    Barbreau, A.; Heremans, R.; Skytte Jensen, B.

    1980-01-01

    Radioactive waste disposal into geological formation is based on the capacity of rocks to confine radioactivity for a long period of time. Radionuclide migration from the repository to the environment depends on different mechanisms and phenomena whose two main ones are groundwater flow and the retention and ion-exchange property of rocks. Many studies are underway presently in EEC countries concerning hydrodynamic characteristics of deep geological formations as well as in radionuclide retention capacity and modelling. Important results have already been achieved which show the complexity of some phenomena and further studies shall principally be developed taking into account real conditions of the repository and its environment

  19. Combining groundwater quality analysis and a numerical flow simulation for spatially establishing utilization strategies for groundwater and surface water in the Pingtung Plain

    Science.gov (United States)

    Jang, Cheng-Shin; Chen, Ching-Fang; Liang, Ching-Ping; Chen, Jui-Sheng

    2016-02-01

    Overexploitation of groundwater is a common problem in the Pingtung Plain area of Taiwan, resulting in substantial drawdown of groundwater levels as well as the occurrence of severe seawater intrusion and land subsidence. Measures need to be taken to preserve these valuable groundwater resources. This study seeks to spatially determine the most suitable locations for the use of surface water on this plain instead of extracting groundwater for drinking, irrigation, and aquaculture purposes based on information obtained by combining groundwater quality analysis and a numerical flow simulation assuming the planning of manmade lakes and reservoirs to the increase of water supply. The multivariate indicator kriging method is first used to estimate occurrence probabilities, and to rank townships as suitable or unsuitable for groundwater utilization according to water quality standards for drinking, irrigation, and aquaculture. A numerical model of groundwater flow (MODFLOW) is adopted to quantify the recovery of groundwater levels in townships after model calibration when groundwater for drinking and agricultural demands has been replaced by surface water. Finally, townships with poor groundwater quality and significant increases in groundwater levels in the Pingtung Plain are prioritized for the groundwater conservation planning based on the combined assessment of groundwater quality and quantity. The results of this study indicate that the integration of groundwater quality analysis and the numerical flow simulation is capable of establishing sound strategies for joint groundwater and surface water use. Six southeastern townships are found to be suitable locations for replacing groundwater with surface water from manmade lakes or reservoirs to meet drinking, irrigation, and aquaculture demands.

  20. Effects of Sea Level Rise on Groundwater Flow Paths in a Coastal Aquifer System

    Science.gov (United States)

    Morrissey, S. K.; Clark, J. F.; Bennett, M. W.; Richardson, E.; Stute, M.

    2008-05-01

    Changes in groundwater flow in the Floridan aquifer system, South Florida, from the rise in sea level at the end of the last glacial period may be indicative of changes coastal aquifers will experience with continued sea level rise. As sea level rises, the hydraulic head near the coast increases. Coastal aquifers can therefore experience decreased groundwater gradients (increased residence times) and seawater intrusion. Stable isotopes of water, dissolved noble gas temperatures, radiocarbon and He concentrations were analyzed in water collected from 68 wells in the Floridan aquifer system throughout South Florida. Near the recharge area, geochemical data along groundwater flow paths in the Upper Floridan aquifer show a transition from recently recharged groundwater to glacial-aged water. Down gradient from this transition, little variation is apparent in the stable isotopes and noble gas recharge temperatures, indicating that most of the Upper Floridan aquifer contains groundwater recharged during the last glacial period. The rapid 120-meter rise in sea level marking the end of the last glacial period increased the hydraulic head in the Floridan aquifer system near the coast, slowing the flow of groundwater from the recharge area to the ocean and trapping glacial-aged groundwater. The raised sea level also flooded half of the Florida platform and caused seawater to intrude into the Lower Floridan. This circulation of seawater in the Lower Floridan continues today as our data indicate that the groundwater is similar to modern seawater with a freshwater component entering vertically from the recharge area to the Upper Floridan.

  1. Numerical simulation of groundwater flow at Puget Sound Naval Shipyard, Naval Base Kitsap, Bremerton, Washington

    Science.gov (United States)

    Jones, Joseph L.; Johnson, Kenneth H.; Frans, Lonna M.

    2016-08-18

    Information about groundwater-flow paths and locations where groundwater discharges at and near Puget Sound Naval Shipyard is necessary for understanding the potential migration of subsurface contaminants by groundwater at the shipyard. The design of some remediation alternatives would be aided by knowledge of whether groundwater flowing at specific locations beneath the shipyard will eventually discharge directly to Sinclair Inlet of Puget Sound, or if it will discharge to the drainage system of one of the six dry docks located in the shipyard. A 1997 numerical (finite difference) groundwater-flow model of the shipyard and surrounding area was constructed to help evaluate the potential for groundwater discharge to Puget Sound. That steady-state, multilayer numerical model with homogeneous hydraulic characteristics indicated that groundwater flowing beneath nearly all of the shipyard discharges to the dry-dock drainage systems, and only shallow groundwater flowing beneath the western end of the shipyard discharges directly to Sinclair Inlet.Updated information from a 2016 regional groundwater-flow model constructed for the greater Kitsap Peninsula was used to update the 1997 groundwater model of the Puget Sound Naval Shipyard. That information included a new interpretation of the hydrogeologic units underlying the area, as well as improved recharge estimates. Other updates to the 1997 model included finer discretization of the finite-difference model grid into more layers, rows, and columns, all with reduced dimensions. This updated Puget Sound Naval Shipyard model was calibrated to 2001–2005 measured water levels, and hydraulic characteristics of the model layers representing different hydrogeologic units were estimated with the aid of state-of-the-art parameter optimization techniques.The flow directions and discharge locations predicted by this updated model generally match the 1997 model despite refinements and other changes. In the updated model, most

  2. Using hydrogeochemical data from natural environments to improve models of radionuclide speciation in groundwaters

    International Nuclear Information System (INIS)

    Read, D.; Hooker, P.

    1991-01-01

    It is essential that computer-based models used in the safety assessment of radioactive waste repositories accurately represent the processes occurring in real field systems. Confidence in long-term predictions of radionuclide migration will then depend upon the completeness of data available, particularly those obtained from the disposal site, and correct implementation of the model. The study of natural geochemical systems provides information on the adequacy of the underlying generic database and enhances our understanding of the transport mechanisms which form the basis of performance assessment. This paper concentrates on speciation-solubility modelling and describes four natural occurrences of uranium, each of which displays a different facet of uranium migration behaviour. The attributes of each site and the means by which uranium is immobilised are described. Retardation is highly species specific and this is illustrated through the use of site data in equilibrium speciation and coupled chemical transport calculations. Oxidation of U(IV) to U(VI) species promotes leaching of uranium ore at all the locations studied, emphasising the need to ensure that reducing conditions persist in a repository dominated by its actinide inventory. 5 figs., 46 refs

  3. Groundwater-flow modeling in the Yucatan karstic aquifer, Mexico

    Science.gov (United States)

    González-Herrera, Roger; Sánchez-y-Pinto, Ismael; Gamboa-Vargas, José

    2002-09-01

    The current conceptual model of the unconfined karstic aquifer in the Yucatan Peninsula, Mexico, is that a fresh-water lens floats above denser saline water that penetrates more than 40 km inland. The transmissivity of the aquifer is very high so the hydraulic gradient is very low, ranging from 7-10 mm/km through most of the northern part of the peninsula. The computer modeling program AQUIFER was used to investigate the regional groundwater flow in the aquifer. The karstified zone was modeled using the assumption that it acts hydraulically similar to a granular, porous medium. As part of the calibration, the following hypotheses were tested: (1) karstic features play an important role in the groundwater-flow system; (2) a ring or belt of sinkholes in the area is a manifestation of a zone of high transmissivity that facilitates the channeling of groundwater toward the Gulf of Mexico; and (3) the geologic features in the southern part of Yucatan influence the groundwater-flow system. The model shows that the Sierrita de Ticul fault, in the southwestern part of the study area, acts as a flow barrier and head values decline toward the northeast. The modeling also shows that the regional flow-system dynamics have not been altered despite the large number of pumping wells because the volume of water pumped is small compared with the volume of recharge, and the well-developed karst system of the region has a very high hydraulic conductivity. Résumé. Le modèle conceptuel classique de l'aquifère karstique libre de la péninsule du Yucatan (Mexique) consiste en une lentille d'eau douce flottant sur une eau salée plus dense qui pénètre à plus de 40 km à l'intérieur des terres. La transmissivité de l'aquifère est très élevée, en sorte que le gradient hydraulique est très faible, compris entre 7 et 10 mm/km dans la plus grande partie du nord de la péninsule. Le modèle AQUIFER a été utilisé pour explorer les écoulements souterrains régionaux dans cet

  4. Simulating the effects of a beaver dam on regional groundwater flow through a wetland

    OpenAIRE

    Kathleen Feiner; Christopher S. Lowry

    2015-01-01

    Study Focus: This research examines a wetland environment before and after the construction of a beaver dam to determine the hydrologic impacts on regional groundwater flow and quantify changes to the capture zone of a wetland pond. Increased hydraulic head behind a newly built beaver dam can cause shifts in the capture zone of a wetland pond. Changes in groundwater flux, and the extent of both the capture and discharge zones of this wetland were examined with the use of a groundwater flow mo...

  5. Modeling groundwater flow at the chemical plant area of the Weldon Spring Site

    International Nuclear Information System (INIS)

    Durham, L.A.

    1992-10-01

    Groundwater flow in the shallow unconfined aquifer at the chemical plant area of the Weldon Spring site, St. Charles County, Missouri, was modeled with the Coupled Fluid, Energy, and Solute Transport (CFEST) groundwater flow and contaminant transport computer code. The modeling was performed in support of a hydrogeological characterization effort that is part of the remedial investigation/feasibility study-environmental impact statement process being carried out by the US Department of Energy at the site. This report presents the results of model development and calibration. In the calibration procedure, the range of field-measured hydrogeological parameters was tested to obtain the best match between model-predicted and measured groundwater elevations. After calibration, the model was used to evaluate whether the presence of an on-site disposal cell would impact the ability to remediate contaminated groundwater beneath the cell. The results of the numerical modeling, which were based on an evaluation of steady-state groundwater flow velocity plots, indicated that groundwater would flow beneath the disposal cell along natural gradients. The presence of a disposal cell would not significantly affect remediation capability for groundwater contamination

  6. ''Blood flow measurements in the irradiated pig skin using β emitters radionuclides''

    International Nuclear Information System (INIS)

    Daburon, F.; Lefaix, J.L.; Leplat, J.J.; Fayart, G.; Delacroix, D.; Le Thanh, P.

    1997-01-01

    Non invasive methods of study of the skin blood flow are numerous, but generally do not give any indication on the cutaneous micro-circulatory flow, except for cutaneous laser Doppler. The isotopic exploration of the skin with injected γ radionuclides, even of weak energy, doe snot allow to characterize the skin blood flow, because of the important contribution of the subcutaneous tissues. The use of β emitters energy spectrum, analyzed by different quantitative methods, are proportional to the thickness of the screen localized between the radioactive source and detector. Using simple and complex phantoms composed of tissue equivalent screens, with 32 P sources placed at different depths, it was possible to study the degradation of β spectra, simulating respectively the sub-epidermis and sub-dermis vascular levels. A modelization and an experimental study in-vivo are proposed in this work, with 32 P phosphate administered intravenously in pigs. (author)

  7. Channel Incision Driven by Suburbanization: Impacts to Riparian Groundwater Flow and Overbank Flow Frequency

    Science.gov (United States)

    Bowles, C. J.; Lawrence, R. L.; Noll, C.; Hancock, G. S.

    2005-12-01

    Channel incision is a widely observed response to increased flow in urbanized watersheds, but the effects of channel lowering on riparian water tables is not well documented. In a rapidly incising suburban stream in the Virginia Coastal Plain, we hypothesize that stream incision has lowered floodplain water tables and decreased the overbank flow frequency. The monitored stream is a tributary to the James River draining 1.3 km2 of which 15% is impervious cover. Incision has occurred largely through upstream migration of a one meter high knickpoint at a rate of ~1.5 m/yr, primarily during high flow events. We installed 63 wells in six stream-perpendicular transects as well as a cluster of wells around the knickpoint to assess water table elevations beneath the floodplain adjacent to the incising stream. Two transects are located 30 and 50 m upstream of the knickpoint in the unincised floodplain, and the remainder are 5, 30, 70, and 100 m downstream in the incised floodplain. In one transect above and two below, pressure transducers attached to dataloggers provide a high-resolution record of water table changes. Erosion pins were installed and channel cross-sections surveyed to determine streambed stability. Significant differences are observed in bank morphology and groundwater flow above vs. below the knickpoint. Above the knickpoint, the banks are stable, ~3 m wide, and ~0.3 m deep, and widen and deepen slightly toward the knickpoint. The water table is relatively flat and is 0.2-0.4 m below the floodplain surface, and groundwater contours suggest flow is parallel to the stream direction. The water table responds immediately to precipitation events, and rises to the floodplain surface in significant rainfall events. Immediately downstream of the knickpoint, channel width increases by about a meter, and stream depth increases to ~1.5 meters. The water table immediately below the knickpoint possesses a steep gradient, and is up to one meter below the floodplain

  8. Approaches to the simulation of unconfined flow and perched groundwater flow in MODFLOW

    Science.gov (United States)

    Bedekar, Vivek; Niswonger, Richard G.; Kipp, Kenneth; Panday, Sorab; Tonkin, Matthew

    2012-01-01

    Various approaches have been proposed to manage the nonlinearities associated with the unconfined flow equation and to simulate perched groundwater conditions using the MODFLOW family of codes. The approaches comprise a variety of numerical techniques to prevent dry cells from becoming inactive and to achieve a stable solution focused on formulations of the unconfined, partially-saturated, groundwater flow equation. Keeping dry cells active avoids a discontinuous head solution which in turn improves the effectiveness of parameter estimation software that relies on continuous derivatives. Most approaches implement an upstream weighting of intercell conductance and Newton-Raphson linearization to obtain robust convergence. In this study, several published approaches were implemented in a stepwise manner into MODFLOW for comparative analysis. First, a comparative analysis of the methods is presented using synthetic examples that create convergence issues or difficulty in handling perched conditions with the more common dry-cell simulation capabilities of MODFLOW. Next, a field-scale three-dimensional simulation is presented to examine the stability and performance of the discussed approaches in larger, practical, simulation settings.

  9. Simulation of the Groundwater-Flow System in Pierce, Polk, and St. Croix Counties, Wisconsin

    Science.gov (United States)

    Juckem, Paul F.

    2009-01-01

    Groundwater is the sole source of residential water supply in Pierce, Polk, and St. Croix Counties, Wisconsin. A regional three-dimensional groundwater-flow model and three associated demonstration inset models were developed to simulate the groundwater-flow systems in the three-county area. The models were developed by the U.S. Geological Survey in cooperation with the three county governments. The objectives of the regional model of Pierce, Polk, and St. Croix Counties were to improve understanding of the groundwaterflow system and to develop a tool suitable for evaluating the effects of potential water-management programs. The regional groundwater-flow model described in this report simulates the major hydrogeologic features of the modeled area, including bedrock and surficial aquifers, groundwater/surface-water interactions, and groundwater withdrawals from high-capacity wells. Results from the regional model indicate that about 82 percent of groundwater in the three counties is from recharge within the counties; 15 percent is from surface-water sources, consisting primarily of recirculated groundwater seepage in areas with abrupt surface-water-level changes, such as near waterfalls, dams, and the downgradient side of reservoirs and lakes; and 4 percent is from inflow across the county boundaries. Groundwater flow out of the counties is to streams (85 percent), outflow across county boundaries (14 percent), and pumping wells (1 percent). These results demonstrate that the primary source of groundwater withdrawn by pumping wells is water that recharges within the counties and would otherwise discharge to local streams and lakes. Under current conditions, the St. Croix and Mississippi Rivers are groundwater discharge locations (gaining reaches) and appear to function as 'fully penetrating' hydraulic boundaries such that groundwater does not cross between Wisconsin and Minnesota beneath them. Being hydraulic boundaries, however, they can change in response to

  10. Numerical groundwater flow calculations at the Finnsjoen site

    International Nuclear Information System (INIS)

    Lindbom, B.; Boghammar, A.; Lindberg, H.; Bjelkaas, J.

    1991-02-01

    The Swedish Nuclear Fuel and Waste Management Company (SKB) has initiated a research project called SKB 91, which is related to performance assessment of repositories for high level waste from nuclear power plants. Specifically the Finnsjoen site is of concern. As part of this research project, the report describes groundwater flow calculations at the Finnsjoen site, located in northern Uppland, approximately 150 km north of Stockholm. The calculations have been performed with the finite element method applying the porous media approach. The project comprises three steps, the first of which is concerned with the presence of salt below a hydraulically significant structure. This step was modelled in two dimensions in a semi-generic fashion, while the two following steps comprised three-dimensional modelling of the site at a semi-regional and a local scale. The semi-regional model covered approximately 43 square km while the area of the local model was roughly 6.6 square km. The semi-regional model included well expressed regional fracture zones that were explicitly modelled in deterministic manner. The modelling was performed with the finite element code NAMMU, used together with the program-package HYPAC. The latter was used for pre- and postprocessing purposes. The modelling was performed with 8-noded brick elements for the three-dimensional calculations, and the two-dimensional model involved the use of 8-noded rectangular elements. The present report is a revised version of a report previously published as a working report. The difference between the present report and the previous one, is that the present report describes the conclusions more site-specifically, the presentation of a number of the cases tackled has been pruned down, some editorial effort has been put into having the volume of the report reduced, and finally the summary has been edited and cut down. (authors)

  11. The role of particulates in radionuclide transport

    International Nuclear Information System (INIS)

    Vilks, P.; Bachinski, D.B.; Vandergraaf, T.T.

    1991-01-01

    The colloid program at AECL Research is focused on characterizing natural particles in groundwater to evaluate their potential role in radiocolloid formation and to form a database for particle migration studies. The main objective of this program has been the study of colloids (1 to 450 nm) and suspended particles (> 450 nm) in fractured granites and sandstone in various locations in Canada and Switzerland. Groundwater particles were found to consist of clay minerals, micas, quartz, feldspar, iron-silica oxides and organic material. In groundwaters from granite, sandstone and clay-rich rock colloid concentrations were less than 5 mg/L. Some of these groundwaters may contain up to 260 mg/L of suspended particles. However, these particles are not expected to be mobile under the natural flow regimes of deep groundwaters. Provided radiocolloid formation is reversible, it is shown that the colloid concentrations observed in groundwaters from granites will have a negligible effect on radionuclide transport even when making the conservative assumption that these particles travel with the velocity of groundwater. For the case of irreversible radiocolloid formation, an equation is presented to calculate the fraction of total radionuclides in the geosphere which will form radiocolloids. The significance of these radiocolloids will depend upon the total amount of radionuclides released to the geosphere and on particle migration properties. (author)

  12. Groundwater flow modelling of Yamuna–Krishni interstream, a part ...

    Indian Academy of Sciences (India)

    interstream, a part of central Ganga Plain ... Water Board (CGWB) and Groundwater Depart- ment of ..... ment, have a discharge rate of 1500 L/min. ... mainly depends on electric power supply, tube- ..... Water Resources, Canberra, Australia.

  13. A generalised groundwater flow equation using the concept of non ...

    African Journals Online (AJOL)

    2006-01-01

    Jan 1, 2006 ... 2 Institute for Groundwater Studies, University of the Free State, PO Box 339, Bloemfontein, South Africa. Abstract ... Keywords: porous media, Darcy Law, integro-differential equations .... f(x) satisfies the boundary conditions.

  14. Effects of groundwater-flow paths on nitrate concentrations across two riparian forest corridors

    Science.gov (United States)

    Speiran, Gary K.

    2010-01-01

    Groundwater levels, apparent age, and chemistry from field sites and groundwater-flow modeling of hypothetical aquifers collectively indicate that groundwater-flow paths contribute to differences in nitrate concentrations across riparian corridors. At sites in Virginia (one coastal and one Piedmont), lowland forested wetlands separate upland fields from nearby surface waters (an estuary and a stream). At the coastal site, nitrate concentrations near the water table decreased from more than 10 mg/L beneath fields to 2 mg/L beneath a riparian forest buffer because recharge through the buffer forced water with concentrations greater than 5 mg/L to flow deeper beneath the buffer. Diurnal changes in groundwater levels up to 0.25 meters at the coastal site reflect flow from the water table into unsaturated soil where roots remove water and nitrate dissolved in it. Decreases in aquifer thickness caused by declines in the water table and decreases in horizontal hydraulic gradients from the uplands to the wetlands indicate that more than 95% of the groundwater discharged to the wetlands. Such discharge through organic soil can reduce nitrate concentrations by denitrification. Model simulations are consistent with field results, showing downward flow approaching toe slopes and surface waters to which groundwater discharges. These effects show the importance of buffer placement over use of fixed-width, streamside buffers to control nitrate concentrations.

  15. Groundwater recharge and flow on Montserrat, West Indies: Insights from groundwater dating

    OpenAIRE

    Hemmings, Brioch; Gooddy, Daren; Whitaker, Fiona; George Darling, W.; Jasim, Alia; Gottsmann, Joachim

    2015-01-01

    Study region Montserrat, Lesser Antilles, Caribbean. Study focus Analysis of δ2H and δ18O isotopes, and chlorofluorocarbon (CFC) anthropogenic tracers in Montserrat groundwater provides insights into the age and provenance of the spring waters. New hydrological insights δ2H and δ18O analysis indicates uniform recharge elevations for groundwaters on Montserrat. CFC-11 and CFC-12 analysis reveals age differences between isotopically similar, high elevation springs and low eleva...

  16. Numerical groundwater-flow modeling to evaluate potential effects of pumping and recharge: implications for sustainable groundwater management in the Mahanadi delta region, India

    Science.gov (United States)

    Sahoo, Sasmita; Jha, Madan K.

    2017-12-01

    Process-based groundwater models are useful to understand complex aquifer systems and make predictions about their response to hydrological changes. A conceptual model for evaluating responses to environmental changes is presented, considering the hydrogeologic framework, flow processes, aquifer hydraulic properties, boundary conditions, and sources and sinks of the groundwater system. Based on this conceptual model, a quasi-three-dimensional transient groundwater flow model was designed using MODFLOW to simulate the groundwater system of Mahanadi River delta, eastern India. The model was constructed in the context of an upper unconfined aquifer and lower confined aquifer, separated by an aquitard. Hydraulic heads of 13 shallow wells and 11 deep wells were used to calibrate transient groundwater conditions during 1997-2006, followed by validation (2007-2011). The aquifer and aquitard hydraulic properties were obtained by pumping tests and were calibrated along with the rainfall recharge. The statistical and graphical performance indicators suggested a reasonably good simulation of groundwater flow over the study area. Sensitivity analysis revealed that groundwater level is most sensitive to the hydraulic conductivities of both the aquifers, followed by vertical hydraulic conductivity of the confining layer. The calibrated model was then employed to explore groundwater-flow dynamics in response to changes in pumping and recharge conditions. The simulation results indicate that pumping has a substantial effect on the confined aquifer flow regime as compared to the unconfined aquifer. The results and insights from this study have important implications for other regional groundwater modeling studies, especially in multi-layered aquifer systems.

  17. Extrahepatic portal hypertension in childhood. Portographic findings and evaluation of hepatic blood flow by computerized radionuclide angiography

    Energy Technology Data Exchange (ETDEWEB)

    Takehara, Hiroo; Komi, Nobuhiko; Goh, Masahiro; Yoshida, Sadahiro; Kameoka, Kazuhiro; Hino, Masao; Sui, Osamu

    1986-05-01

    Four pediatric patients with extrahepatic portal hypertension had undergone portography and computerized radionuclide angiography in order to examine shape of portal system and to evaluate hepatic blood flow before and aftersurgical treatment. In all patients, cavernous transformation of portal system was demonstrated by portography, and in one of them spontaneous splenorenal shunt occurred. In 3 of them, who underwent esophageal transsection combined with paraesophagogastric devascularization and splenectomy, so-called direct operation, increase of portal blood flow was revealed by computerized radionuclide angiography. It is suggested that direct operation increasing portal blood flow after surgery is effective in treating extrahepatic portal hypertension in childhood.

  18. Hydrochemistry of the groundwater flow systems in the Harwell region

    International Nuclear Information System (INIS)

    Alexander, J.

    1984-12-01

    A comprehensive range of geochemical and isotopic parameters were analysed in the groundwater samples taken from the high permeability formations in the Harwell region. These analyses were undertaken as part of a hydro-chemical validation of groundwater circulation patterns derived from potentiometric data. Hydro-chemical investigations were concentrated upon the Corallian and Great Oolite formations since these respectively overlie and underlie the Oxford Clay. (author)

  19. Site-scale groundwater flow modelling of Ceberg

    Energy Technology Data Exchange (ETDEWEB)

    Walker, D. [Duke Engineering and Services (United States); Gylling, B. [Kemakta Konsult AB, Stockholm (Sweden)

    1999-06-01

    The Swedish Nuclear Fuel and Waste Management Company (SKB) SR 97 study is a comprehensive performance assessment illustrating the results for three hypothetical repositories in Sweden. In support of SR 97, this study examines the hydrogeologic modelling of the hypothetical site called Ceberg, which adopts input parameters from the SKB study site near Gideaa, in northern Sweden. This study uses a nested modelling approach, with a deterministic regional model providing boundary conditions to a site-scale stochastic continuum model. The model is run in Monte Carlo fashion to propagate the variability of the hydraulic conductivity to the advective travel paths from representative canister locations. A series of variant cases addresses uncertainties in the inference of parameters and the model of conductive fracturezones. The study uses HYDRASTAR, the SKB stochastic continuum (SC) groundwater modelling program, to compute the heads, Darcy velocities at each representative canister position, and the advective travel times and paths through the geosphere. The volumetric flow balance between the regional and site-scale models suggests that the nested modelling and associated upscaling of hydraulic conductivities preserve mass balance only in a general sense. In contrast, a comparison of the base and deterministic (Variant 4) cases indicates that the upscaling is self-consistent with respect to median travel time and median canister flux. These suggest that the upscaling of hydraulic conductivity is approximately self-consistent but the nested modelling could be improved. The Base Case yields the following results for a flow porosity of {epsilon}{sub f} 10{sup -4} and a flow-wetted surface area of a{sub r} = 0.1 m{sup 2}/(m{sup 3} rock): The median travel time is 1720 years. The median canister flux is 3.27x10{sup -5} m/year. The median F-ratio is 1.72x10{sup 6} years/m. The base case and the deterministic variant suggest that the variability of the travel times within

  20. Site-scale groundwater flow modelling of Ceberg

    International Nuclear Information System (INIS)

    Walker, D.; Gylling, B.

    1999-06-01

    The Swedish Nuclear Fuel and Waste Management Company (SKB) SR 97 study is a comprehensive performance assessment illustrating the results for three hypothetical repositories in Sweden. In support of SR 97, this study examines the hydrogeologic modelling of the hypothetical site called Ceberg, which adopts input parameters from the SKB study site near Gideaa, in northern Sweden. This study uses a nested modelling approach, with a deterministic regional model providing boundary conditions to a site-scale stochastic continuum model. The model is run in Monte Carlo fashion to propagate the variability of the hydraulic conductivity to the advective travel paths from representative canister locations. A series of variant cases addresses uncertainties in the inference of parameters and the model of conductive fracture zones. The study uses HYDRASTAR, the SKB stochastic continuum (SC) groundwater modelling program, to compute the heads, Darcy velocities at each representative canister position, and the advective travel times and paths through the geosphere. The volumetric flow balance between the regional and site-scale models suggests that the nested modelling and associated upscaling of hydraulic conductivities preserve mass balance only in a general sense. In contrast, a comparison of the base and deterministic (Variant 4) cases indicates that the upscaling is self-consistent with respect to median travel time and median canister flux. These suggest that the upscaling of hydraulic conductivity is approximately self-consistent but the nested modelling could be improved. The Base Case yields the following results for a flow porosity of ε f 10 -4 and a flow-wetted surface area of a r = 0.1 m 2 /(m 3 rock): The median travel time is 1720 years. The median canister flux is 3.27x10 -5 m/year. The median F-ratio is 1.72x10 6 years/m. The base case and the deterministic variant suggest that the variability of the travel times within individual realisations is due to the

  1. Increased Concentrations of Short-Lived Decay-Series Radionuclides in Groundwaters Underneath the Nopal I Uranium Deposit at Pena Blanca, Mexico

    Science.gov (United States)

    Luo, S.; Ku, T.; Todd, V.; Murrell, M. T.; Dinsmoor, J. C.

    2007-05-01

    The Nopal I uranium ore deposit at Pena Blanca, Mexico, located at > 200 meters above the groundwater table, provides an ideal natural analog for quantifying the effectiveness of geological barrier for isolation of radioactive waste nuclides from reaching the human environments through ground water transport. To fulfill such natural analog studies, three wells (PB1, PB2, and PB3 respectively) were drilled at the site from the land surface down to the saturated groundwater zone and ground waters were collected from each of these wells through large- volume sampling/in-situ Mn-filter filtration for analyses of short-lived uranium/thorium-series radionuclides. Our measurements from PB1 show that the groundwater standing in the hole has much lower 222Rn activity than the freshly pumped groundwater. From this change in 222Rn activity, we estimate the residence time of groundwater in PB1 to be about 20 days. Our measurements also show that the activities of short-lived radioisotopes of Th (234Th), Ra (228Ra, 224Ra, 223Ra), Rn (222Rn), Pb (210Pb), and Po (210Po) in PB1, PB2, and PB3 are all significantly higher than those from the other wells near the Nopal I site. These high activities provide evidence for the enrichment of long-lived U and Ra isotopes in the groundwater as well as in the associated adsorbed phases on the fractured aquifer rocks underneath the ore deposit. Such enrichment suggests a rapid dissolution of U and Ra isotopes from the uranium ore deposit in the vadose zone and the subsequent migration to the groundwater underneath. A reactive transport model can be established to characterize the in-situ transport of radionuclides at the site. The observed change of 222Rn activity at PB1 also suggests that the measured high radioactivityies in ground waters from the site isare not an artifact of drilling operations. However, further studies are needed to assess if or to what extent the radionuclide migration is affected by the previous mining activities at

  2. Trace Metals in Groundwater and the Vadose Zone Calcite: In Situ Containment and Stabilization of Strontium-90 and Other Divalent Metals and Radionuclides at Arid West DOE

    International Nuclear Information System (INIS)

    Smith, Robert W.

    2004-01-01

    Radionuclide and metal contaminants such as strontium-90 are present beneath U.S. Department of Energy (DOE) lands in both the groundwater (e.g., 100-N area at Hanford, WA) and vadose zone (e.g., Idaho Nuclear Technology and Engineering Center at the Idaho National Engineering and Environmental Laboratory). In situ containment and stabilization of these contaminants is a cost-effective treatment strategy. However, implementing in situ containment and stabilization approaches requires definition of the mechanisms that control contaminant sequestration. We are investigating the in situ immobilization of radionuclides or contaminant metals (e.g., strontium-90) by their facilitated co-precipitation with calcium carbonate in groundwater and vadose zone systems. Our facilitated approach, shown schematically in Figure 1, relies upon the hydrolysis of introduced urea to cause the acceleration of calcium carbonate precipitation (and trace metal co-precipitation) by increasing pH and alkalinity. Subsurface urea hydrolysis is catalyzed by the urease enzyme, which may be either introduced with the urea or produced in situ by ubiquitous subsurface urea hydrolyzing microorganisms. Because the precipitation process tends to be irreversible and many western aquifers are saturated with respect to calcite, the co-precipitated metals and radionuclides will be effectively removed from the aqueous phase over the long-term. Another advantage of the ureolysis approach is that the ammonium ions produced by the reaction can exchange with radionuclides sorbed to subsurface minerals, thereby enhancing the availability of the radionuclides for re-capture in a more stable solid phase (co-precipitation rather than adsorption)

  3. Field studies about radionuclide migration natural analogues and faults in clays

    International Nuclear Information System (INIS)

    Williams, G.M.; Hooker, P.J.; Brightman, M.A.

    1990-01-01

    This report puts together final reports of CEC contracts about the following topics: in situ determination of the effects of organics on the mobility of radionuclides in controlled conditions of groundwater flow (Drigg site); natural analogue studies of radionuclide migration (Loch Lomond, Broubster, Needle's Eye); faults in clays: their detection and characterization (Down Ampney site)

  4. Influences of groundwater extraction on flow dynamics and arsenic levels in the western Hetao Basin, Inner Mongolia, China

    Science.gov (United States)

    Zhang, Zhuo; Guo, Huaming; Zhao, Weiguang; Liu, Shuai; Cao, Yongsheng; Jia, Yongfeng

    2018-04-01

    Data on spatiotemporal variations in groundwater levels are crucial for understanding arsenic (As) behavior and dynamics in groundwater systems. Little is known about the influences of groundwater extraction on the transport and mobilization of As in the Hetao Basin, Inner Mongolia (China), so groundwater levels were recorded in five monitoring wells from 2011 to 2016 and in 57 irrigation wells and two multilevel wells in 2016. Results showed that groundwater level in the groundwater irrigation area had two troughs each year, induced by extensive groundwater extraction, while groundwater levels in the river-diverted (Yellow River) water irrigation area had two peaks each year, resulting from surface-water irrigation. From 2011 to 2016, groundwater levels in the groundwater irrigation area presented a decreasing trend due to the overextraction. Groundwater samples were taken for geochemical analysis each year in July from 2011 to 2016. Increasing trends were observed in groundwater total dissolved solids (TDS) and As. Owing to the reverse groundwater flow direction, the Shahai Lake acts as a new groundwater recharge source. Lake water had flushed the near-surface sediments, which contain abundant soluble components, and increased groundwater salinity. In addition, groundwater extraction induced strong downward hydraulic gradients, which led to leakage recharge from shallow high-TDS groundwater to the deep semiconfined aquifer. The most plausible explanation for similar variations among As, Fe(II) and total organic carbon (TOC) concentrations is the expected dissimilatory reduction of Fe(III) oxyhydroxides.

  5. A study on the groundwater flow system for deep geological disposal of high level radioactive waste in Korea

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chun Soo; Kim, Kyung Su; Bae, Dae Seok; Park, Byoung Yoon; Koh, Young Kown [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2000-03-01

    The basic framework of groundwater flow is defined as a conceptual 3-D unit of groundwater system based on hydrogeological environments. The fundamental parameters consisting of groundwater system should include topography, geology and climatic conditions. Climatic conditions control the distribution and amounts of groundwater in an interesting study area. The driving forces responsible for groundwater movement are mainly determined by topographic characteristics. The configuration of groundwater system is also controlled by topography. The geological setting and structures control the reservoir size and groundwater flow path. The hydrogeological setting in Korea was classified by primarily topographic characteristics and considered by geological structures and tectonic division. The regional groundwater regime can be grouped into 3 regimes by tectonic setting and four groundwater regions based on an altitude. 35 refs., 9 figs., 21 tabs. (Author)

  6. Documentation for the MODFLOW 6 Groundwater Flow Model

    Science.gov (United States)

    Langevin, Christian D.; Hughes, Joseph D.; Banta, Edward R.; Niswonger, Richard G.; Panday, Sorab; Provost, Alden M.

    2017-08-10

    This report documents the Groundwater Flow (GWF) Model for a new version of MODFLOW called MODFLOW 6. The GWF Model for MODFLOW 6 is based on a generalized control-volume finite-difference approach in which a cell can be hydraulically connected to any number of surrounding cells. Users can define the model grid using one of three discretization packages, including (1) a structured discretization package for defining regular MODFLOW grids consisting of layers, rows, and columns, (2) a discretization by ver­tices package for defining layered unstructured grids consisting of layers and cells, and (3) a general unstruc­tured discretization package for defining flexible grids comprised of cells and their connection properties. For layered grids, a new capability is available for removing thin cells and vertically connecting cells overlying and underlying the thin cells. For complex problems involving water-table conditions, an optional Newton-Raphson formulation, based on the formulations in MODFLOW-NWT and MODFLOW-USG, can be acti­vated. Use of the Newton-Raphson formulation will often improve model convergence and allow solutions to be obtained for difficult problems that cannot be solved using the traditional wetting and drying approach. The GWF Model is divided into “packages,” as was done in previous MODFLOW versions. A package is the part of the model that deals with a single aspect of simulation. Packages included with the GWF Model include those related to internal calculations of groundwater flow (discretization, initial conditions, hydraulic conduc­tance, and storage), stress packages (constant heads, wells, recharge, rivers, general head boundaries, drains, and evapotranspiration), and advanced stress packages (streamflow routing, lakes, multi-aquifer wells, and unsaturated zone flow). An additional package is also available for moving water available in one package into the individual features of the advanced stress packages. The GWF Model

  7. A process for containment removal and waste volume reduction to remediate groundwater containing certain radionuclides, toxic metals and organics

    International Nuclear Information System (INIS)

    Buckley, L.P.; Killey, D.R.W.; Vijayan, S.; Wong, P.C.F.

    1992-09-01

    A project to remove groundwater contaminants by an improved treatment process was performed during 1990 October--1992 March by Atomic Energy of Canada Limited for the United States Department of Energy, managed by Argonne National Laboratory. The goal was to generate high-quality effluent while minimizing secondary waste volume. Two effluent target levels, within an order of magnitude, or less than the US Drinking Water Limit, were set to judge the process effectiveness. The program employed mixed waste feeds containing cadmium, uranium, lead, iron, calcium, strontium-85-90, cesium-137, benzene and trichlorethylene in simulated and actual groundwater and soil leachate solutions. A combination of process steps consisting of sequential chemical conditioning, cross-flow microfiltration and dewatering by low temperature-evaporation, or filter pressing were effective for the treatment of mixed waste having diverse physico-chemical properties. A simplified single-stage version of the process was implemented to treat ground and surface waters contaminated with strontium-90 at the Chalk River Laboratories site. Effluent targets and project goals were met successfully

  8. Hydrochemistry in the development of groundwater flow models at the Hanford site

    International Nuclear Information System (INIS)

    Early, T.O.

    1986-01-01

    Site characterization activities in progress at the Hanford Site include efforts to understand the groundwater flow regime within the Columbia River Basalt Group. Hydrochemical data from deep boreholes at Hanford suggest that groundwater has migrated upward at an unknown rate from the underlying sediments and mixed with more dilute shallow groundwaters within basalt aquifers. The driving force for upward flow is hypothesized to result from a regional flow system. Detailed analysis of deep groundwaters indicates that two major types exist. For example, water underlying the western part of the Site are sulfate poor and associated with relatively abundant dissolved methane. Deep groundwaters of the second type, lying to the east, are relatively sulfate rich but contain essentially no methane. Specific features of the source regions that yield these different geochemical types are poorly known but association of the western waters with methane-producing coal strata is proposed. At the level of the proposed repository evidence seems to point to little lateral flow. At shallower depths a somewhat more active lateral flow system is possible. The direction of lateral flow, whatever its rate, appears to be structurally controlled

  9. Radionuclide migration in groundwater at a low-level waste disposal site: a comparison of predictive performance modeling versus field observations

    International Nuclear Information System (INIS)

    Robertson, D.E.; Myers, D.A.; Bergeron, M.P.; Champ, D.R.; Killey, R.W.D.; Moltyaner, G.L.; Young, J.L.

    1985-08-01

    This paper describes a project which is structured to test the concept of modeling a shallow land low-level waste burial site. The project involves a comparison of the actual observed radionuclide migration in groundwaters at a 30-year-old well-monitored field site with the results of predictive transport modeling. The comparison is being conducted as a cooperative program with the Atomic Energy of Canada Ltd. (AECL) at the low-level waste management area at the Chalk River Nuclear Laboratories, Ontario, Canada. A joint PNL-AECL field inviestigation was conducted in 1983 and 1984 to complement the existing extensive data base on actual radionuclide migration. Predictive transport modeling is currently being conducted for this site; first, as if it were a new location being considered for a low-level waste shallow-land burial site and only minimal information about the site were available, and second, utilizing the extensive data base available for the site. The modeling results will then be compared with the empirical observations to provide insight into the level of effort needed to reasonably predict the spacial and temporal movement of radionuclides in the groundwater enviroment. 8 refs., 5 figs.,

  10. Radionuclide migration in groundwater at a low-level waste disposal site: a comparison of predictive performance modeling versus field observations

    International Nuclear Information System (INIS)

    Robertson, D.E.; Myers, D.A.; Abel, K.H.; Bergeron, M.P.; Champ, D.R.; Killey, R.W.D.; Moltyaner, G.L.; Young, J.L.

    1986-01-01

    This paper describes a project which is structured to test the concept of modeling a shallow land low-level waste burial site. The project involves a comparison of the actual observed radionuclide migration in groundwaters at a 30-year old well-monitored field site with the results of predictive transport modeling. The comparison is being conducted as a cooperative program with the Atomic Energy of Canada Ltd. (AECL) at the low-level waste management area at the Chalk River Nuclear Laboratories, Ontario, Canada. A joint PNL-AECL field investigation was conducted in 1983 and 1984 to compliment the existing extensive data base on actual radionuclide migration. Predictive transport modeling is currently being conducted for this site; first, as if it were a new location being considered for a low-level waste shallow-land burial site and only minimal information about the site were available, and second, utilizing the extensive data base available for the site. The modeling results will then be compared with the level of effort needed to reasonably predict the spacial and temporal movement of radionuclides in the groundwater environment

  11. Recharge and Lateral Groundwater Flow Boundary Conditions for the Saturated Zone Site-Scale Flow and Transport Model

    Energy Technology Data Exchange (ETDEWEB)

    B. Arnold; T. Corbet

    2001-12-18

    The purpose of the flow boundary conditions analysis is to provide specified-flux boundary conditions for the saturated zone (SZ) site-scale flow and transport model. This analysis is designed to use existing modeling and analysis results as the basis for estimated groundwater flow rates into the SZ site-scale model domain, both as recharge at the upper (water table) boundary and as underflow at the lateral boundaries. The objective is to provide consistency at the boundaries between the SZ site-scale flow model and other groundwater flow models. The scope of this analysis includes extraction of the volumetric groundwater flow rates simulated by the SZ regional-scale flow model to occur at the lateral boundaries of the SZ site-scale flow model and the internal qualification of the regional-scale model for use in this analysis model report (AMR). In addition, the scope includes compilation of information on the recharge boundary condition taken from three sources: (1) distributed recharge as taken from the SZ regional-scale flow model, (2) recharge below the area of the unsaturated zone (UZ) site-scale flow model, and (3) focused recharge along the Fortymile Wash channel.

  12. Complexity in the validation of ground-water travel time in fractured flow and transport systems

    International Nuclear Information System (INIS)

    Davies, P.B.; Hunter, R.L.; Pickens, J.F.

    1991-01-01

    Ground-water travel time is a widely used concept in site assessment for radioactive waste disposal. While ground-water travel time was originally conceived to provide a simple performance measure for evaluating repository sites, its definition in many flow and transport environments is ambiguous. The U.S. Department of Energy siting guidelines (10 CFR 960) define ground-water travel time as the time required for a unit volume of water to travel between two locations, calculated by dividing travel-path length by the quotient of average ground-water flux and effective porosity. Defining a meaningful effective porosity in a fractured porous material is a significant problem. Although the Waste Isolation Pilot Plant (WIPP) is not subject to specific requirements for ground-water travel time, travel times have been computed under a variety of model assumptions. Recently completed model analyses for WIPP illustrate the difficulties in applying a ground-water travel-time performance measure to flow and transport in fractured, fully saturated flow systems. Computer code used: SWIFT II (flow and transport code). 4 figs., 12 refs

  13. Finite-element three-dimensional ground-water (FE3DGW) flow model - formulation, program listings and users' manual

    International Nuclear Information System (INIS)

    Gupta, S.K.; Cole, C.R.; Bond, F.W.

    1979-12-01

    The Assessment of Effectiveness of Geologic Isolation Systems (AEGIS) Program is developing and applying the methodology for assessing the far-field, long-term post-closure safety of deep geologic nuclear waste repositories. AEGIS is being performed by Pacific Northwest Laboratory (PNL) under contract with the Office of Nuclear Waste Isolation (OWNI) for the Department of Energy (DOE). One task within AEGIS is the development of methodology for analysis of the consequences (water pathway) from loss of repository containment as defined by various release scenarios. Analysis of the long-term, far-field consequences of release scenarios requires the application of numerical codes which simulate the hydrologic systems, model the transport of released radionuclides through the hydrologic systems to the biosphere, and, where applicable, assess the radiological dose to humans. Hydrologic and transport models are available at several levels of complexity or sophistication. Model selection and use are determined by the quantity and quality of input data. Model development under AEGIS and related programs provides three levels of hydrologic models, two levels of transport models, and one level of dose models (with several separate models). This document consists of the description of the FE3DGW (Finite Element, Three-Dimensional Groundwater) Hydrologic model third level (high complexity) three-dimensional, finite element approach (Galerkin formulation) for saturated groundwater flow

  14. Three-dimensional simulation of flow, salinity, sediment, and radionuclide movements in the Hudson River estuary

    International Nuclear Information System (INIS)

    Onishi, Y.; Trent, D.S.

    1985-04-01

    The three-dimensional, finite difference model, FLESCOT simulates time-varying movements of flow, turbulent kinetic energy, salinity, water temperature, sediment, and contaminants in estuarine, coastal, and ocean waters. The model was applied to a 106-km (66-mi) reach of the Hudson River estuary in New York between Chelsea and the mouth of the river. It predicted the time-varying, three-dimensional distributions of tidal flow, salinity, three separate groups of sediments (i.e., sand, silt, and clay), and a radionuclide ( 137 Cs) in both dissolved and particulate (those sorbed by sediments) forms for over 40 days. The model also calculated riverbed elevation changes caused by sediment deposition and bed erosion, bed sediment size distribution and armoring, and distributions of the particulate 137 Cs sorbed by sand, silt, and clay in the bed

  15. Flow modelling and radionuclide transport research and development in saturated and unsaturated soils

    International Nuclear Information System (INIS)

    Carvalho Filho, Carlos Alberto de; Branco, Otavio Eurico de Aquino; Loureiro, Celso de Oliveira

    1996-01-01

    The Engenho Nogueira Hydrogeological Project, PROHBEN, was idealized with the goal of implementing an Experimental Hydrogeological basin within its limits, in order to permit the development of hydrogeological studies and techniques, mainly in the modeling of flow and transport of contaminants (radionuclides) in the saturated and unsaturated porous media. The PROHBEN is located in Belo Horizonte, Minas Gerais, amounting a 5 km 2 area. The local porous-granular, heterogeneous and anisotropic, water-table aquifer reaches 40 meters of thickness, and is compound mainly by alluvial deposits and alteration rocks products, with a sandy texture. The flow and transport modeling are being done using the Modflow and MT3D codes. Three master degree researches are being done in the PROHBEN area and one expects is that more researchers come to use this experimental site. (author)

  16. Simulation of Ground-Water Flow and Effects of Ground-Water Irrigation on Base Flow in the Elkhorn and Loup River Basins, Nebraska

    Science.gov (United States)

    Peterson, Steven M.; Stanton, Jennifer S.; Saunders, Amanda T.; Bradley, Jesse R.

    2008-01-01

    Irrigated agriculture is vital to the livelihood of communities in the Elkhorn and Loup River Basins in Nebraska, and ground water is used to irrigate most of the cropland. Concerns about the sustainability of ground-water and surface-water resources have prompted State and regional agencies to evaluate the cumulative effects of ground-water irrigation in this area. To facilitate understanding of the effects of ground-water irrigation, a numerical computer model was developed to simulate ground-water flow and assess the effects of ground-water irrigation (including ground-water withdrawals, hereinafter referred to as pumpage, and enhanced recharge) on stream base flow. The study area covers approximately 30,800 square miles, and includes the Elkhorn River Basin upstream from Norfolk, Nebraska, and the Loup River Basin upstream from Columbus, Nebraska. The water-table aquifer consists of Quaternary-age sands and gravels and Tertiary-age silts, sands, and gravels. The simulation was constructed using one layer with 2-mile by 2-mile cell size. Simulations were constructed to represent the ground-water system before 1940 and from 1940 through 2005, and to simulate hypothetical conditions from 2006 through 2045 or 2055. The first simulation represents steady-state conditions of the system before anthropogenic effects, and then simulates the effects of early surface-water development activities and recharge of water leaking from canals during 1895 to 1940. The first simulation ends at 1940 because before that time, very little pumpage for irrigation occurred, but after that time it became increasingly commonplace. The pre-1940 simulation was calibrated against measured water levels and estimated long-term base flow, and the 1940 through 2005 simulation was calibrated against measured water-level changes and estimated long-term base flow. The calibrated 1940 through 2005 simulation was used as the basis for analyzing hypothetical scenarios to evaluate the effects of

  17. Modeling Groundwater Flow System of a Drainage Basin in the Basement Complex Environment of Southwestern Nigera

    Science.gov (United States)

    Akinwumiju, Akinola S.; Olorunfemi, Martins O.

    2018-05-01

    This study attempted to model the groundwater flow system of a drainage basin within the Basement Complex environment of Southwestern Nigeria. Four groundwater models were derived from Vertical Electrical Sounding (VES) Data, remotely sensed data, geological information (hydrolineaments and lithology) and borehole data. Subsequently, two sub-surface (local and regional) flow systems were delineated in the study area. While the local flow system is controlled by surface topography, the regional flow system is controlled by the networks of intermediate and deep seated faults/fractures. The local flow system is characterized by convergence, divergence, inflow and outflow in places, while the regional flow system is dominated by NNE-SSW and W-E flow directions. Minor flow directions include NNW-SSE and E-W with possible linkages to the main flow-paths. The NNE-SSW regional flow system is a double open ended flow system with possible linkage to the Niger Trough. The W-E regional flow system is a single open ended system that originates within the study area (with possible linkage to the NNE-SSW regional flow system) and extends to Ikogosi in the adjoining drainage basin. Thus, the groundwater drainage basin of the study area is much larger and extensive than its surface drainage basin. The all year round flowing (perennial) rivers are linked to groundwater outcrops from faults/fractures and contact zones. Consequently, larger percentage of annual rainwater usually leaves the basin in form of runoff and base flow. Therefore, the basin is categorized as a donor basin but with suspected subsurface water input at its northeastern axis.

  18. Groundwater Flow Model of Corrective Action Units 101 and 102: Central and Western Pahute Mesa, Nevada Test Site, Nye County, Nevada, Revision 0

    Energy Technology Data Exchange (ETDEWEB)

    Greg Ruskauff

    2006-06-01

    The Pahute Mesa groundwater flow model supports the FFACO UGTA corrective action strategy objective of providing an estimate of the vertical and horizontal extent of contaminant migration for each CAU in order to predict contaminant boundaries. A contaminant boundary is the model-predicted perimeter that defines the extent of radionuclide-contaminated groundwater from underground nuclear testing above background conditions exceeding Safe Drinking Water Act (SDWA) standards. The contaminant boundary will be composed of both a perimeter boundary and a lower hydrostratigraphic unit (HSU) boundary. Additional results showing contaminant concentrations and the location of the contaminant boundary at selected times will also be presented. These times may include the verification period, the end of the five-year proof-of-concept period, as well as other times that are of specific interest. The FFACO (1996) requires that the contaminant transport model predict the contaminant boundary at 1,000 years and “at a 95% level of confidence.” The Pahute Mesa Phase I flow model described in this report provides, through the flow fields derived from alternative hydrostratigraphic framework models (HFMs) and recharge models, one part of the data required to compute the contaminant boundary. Other components include the simplified source term model, which incorporates uncertainty and variability in the factors that control radionuclide release from an underground nuclear test (SNJV, 2004a), and the transport model with the concomitant parameter uncertainty as described in Shaw (2003). The uncertainty in all the above model components will be evaluated to produce the final contaminant boundary. This report documents the development of the groundwater flow model for the Central and Western Pahute Mesa CAUs.

  19. Spatial distribution of groundwater recharge and base flow: Assessment of controlling factors

    Directory of Open Access Journals (Sweden)

    Z. Zomlot

    2015-09-01

    New hydrological insights for the region: The average resulting recharge is 235 mm/year and occurs mainly in winter. The overall moderate correlation between base flow estimates and modeled recharge rates indicates that base flow is a reasonable proxy of recharge. Groundwater recharge variation was explained in order of importance by precipitation, soil texture and vegetation cover; while base flow variation was strongly controlled by vegetation cover and groundwater depth. The results of this study highlight the important role of spatial variables in estimation of recharge and base flow. In addition, the prominent role of vegetation makes clear the potential importance of land-use changes on recharge and hence the need to include a proper strategy for land-use change in sustainable management of groundwater resources.

  20. Investigations of groundwater system and simulation of regional groundwater flow for North Penn Area 7 Superfund site, Montgomery County, Pennsylvania

    Science.gov (United States)

    Senior, Lisa A.; Goode, Daniel J.

    2013-01-01

    Groundwater in the vicinity of several industrial facilities in Upper Gwynedd Township and vicinity, Montgomery County, in southeast Pennsylvania has been shown to be contaminated with volatile organic compounds (VOCs), the most common of which is the solvent trichloroethylene (TCE). The 2-square-mile area was placed on the National Priorities List as the North Penn Area 7 Superfund site by the U.S. Environmental Protection Agency (USEPA) in 1989. The U.S. Geological Survey (USGS) conducted geophysical logging, aquifer testing, and water-level monitoring, and measured streamflows in and near North Penn Area 7 from fall 2000 through fall 2006 in a technical assistance study for the USEPA to develop an understanding of the hydrogeologic framework in the area as part of the USEPA Remedial Investigation. In addition, the USGS developed a groundwater-flow computer model based on the hydrogeologic framework to simulate regional groundwater flow and to estimate directions of groundwater flow and pathways of groundwater contaminants. The study area is underlain by Triassic- and Jurassic-age sandstones and shales of the Lockatong Formation and Brunswick Group in the Mesozoic Newark Basin. Regionally, these rocks strike northeast and dip to the northwest. The sequence of rocks form a fractured-sedimentary-rock aquifer that acts as a set of confined to partially confined layers of differing permeabilities. Depth to competent bedrock typically is less than 20 ft below land surface. The aquifer layers are recharged locally by precipitation and discharge locally to streams. The general configuration of the potentiometric surface in the aquifer is similar to topography, except in areas affected by pumping. The headwaters of Wissahickon Creek are nearby, and the stream flows southwest, parallel to strike, to bisect North Penn Area 7. Groundwater is pumped in the vicinity of North Penn Area 7 for industrial use, public supply, and residential supply. Results of field investigations

  1. Mass transport by groundwater

    International Nuclear Information System (INIS)

    Ledoux, E.; Goblet, P.; Jamet, Ph.; De Marsily, G.; Des Orres, P.E.; Lewi, J.

    1991-01-01

    The first analyses of the safety of radioactive waste disposal published in 1970s were mostly of a generic type using the models of radionuclide migration in the geosphere. These simply constructed models gave way to more sophisticated techniques in order to represent better the complexity and diversity of geological media. In this article, it is attempted to review the various concepts used to quantify radionuclide migration and the evolution of their incorporation into the models. First, it was examined how the type of discontinuity occurring in geological media affects the choice of a representative model. The principle of transport in the subsurface was reviewed, and the effect that coupled processes exert to groundwater flow and mass migration was discussed. The processes that act directly to cause groundwater flow were distinguished. The method of validating such models by comparing the results with the geochemical systems in nature was explained. (K.I.)

  2. Hydrogeological and Groundwater Flow Model for C, K, L, and P Reactor Areas, Savannah River Site, Aiken, South Carolina

    International Nuclear Information System (INIS)

    Flach, G.P.

    1999-01-01

    A regional groundwater flow model encompassing approximately 100 mi 2 surrounding the C, K. L. and P reactor areas has been developed. The Reactor flow model is designed to meet the planning objectives outlined in the General Groundwater Strategy for Reactor Area Projects by providing a common framework for analyzing groundwater flow, contaminant migration and remedial alternatives within the Reactor Projects team of the Environmental Restoration Department

  3. Hydrogeological and Groundwater Flow Model for C, K, L, and P Reactor Areas, Savannah River Site, Aiken, South Carolina

    Energy Technology Data Exchange (ETDEWEB)

    Flach, G.P.

    1999-02-24

    A regional groundwater flow model encompassing approximately 100 mi{sup 2} surrounding the C, K. L. and P reactor areas has been developed. The Reactor flow model is designed to meet the planning objectives outlined in the General Groundwater Strategy for Reactor Area Projects by providing a common framework for analyzing groundwater flow, contaminant migration and remedial alternatives within the Reactor Projects team of the Environmental Restoration Department.

  4. Determination of Groundwater Flows Pattern in Surakarta Region Using the Activity Ratio of Tritium

    International Nuclear Information System (INIS)

    Wisjachudin Faisal; Agus Sulistyono; Brotopuspito, Kirbani Sri; Budi Legowo

    2002-01-01

    Tritium activity analysis on groundwater samples has been carried out at 13 different locations in Surakarta regency in order to determine the groundwater flow pattern. Tritium activity in the groundwater is measured by LSC (Liquid Scintillation Counter) Tri-Carb 2700TR Measurement of the optimum activity is done on sample volume ratio with cocktail 7.4 : 12.6 in operation 0.5 - 4.5 keV. The highest result fulfilled in the location of Lor In Hotel for 1566 dpm and the lowest is in the location of Kadipiro for 0.03 dpm. Those data have shown that groundwater flow come from western area to eastern area of Surakarta city. (author)

  5. Effect of coupling behavior on groundwater flow for geological disposal of radioactive high level waste

    International Nuclear Information System (INIS)

    Kurikami, Hiroshi; Kobayashi, Akira; Ohnishi, Yuzo; Chijimatsu, Masakazu

    2003-01-01

    In order to estimate the effects of coupled thermal-hydraulic-mechanical phenomena in near-field for geological disposal of high-level radioactive waste on a vast groundwater flow system, a far-field analysis was simulated based on the results of the simulation of coupled phenomena in near-field using averaged tensor and heat flux. From the results of the coupled analyses of near-field and far-field it was clarified that groundwater flow system was influenced by coupled phenomena in near-field. Moreover, it can be said that groundwater flux into a disposal tunnel is regarded as a complement to safety assessment of a disposal because it strongly correlates with traveling time of groundwater. (author)

  6. Shallow groundwater in the Matanuska-Susitna Valley, Alaska—Conceptualization and simulation of flow

    Science.gov (United States)

    Kikuchi, Colin P.

    2013-01-01

    The Matanuska-Susitna Valley is in the Upper Cook Inlet Basin and is currently undergoing rapid population growth outside of municipal water and sewer service areas. In response to concerns about the effects of increasing water use on future groundwater availability, a study was initiated between the Alaska Department of Natural Resources and the U.S. Geological Survey. The goals of the study were (1) to compile existing data and collect new data to support hydrogeologic conceptualization of the study area, and (2) to develop a groundwater flow model to simulate flow dynamics important at the regional scale. The purpose of the groundwater flow model is to provide a scientific framework for analysis of regional-scale groundwater availability. To address the first study goal, subsurface lithologic data were compiled into a database and were used to construct a regional hydrogeologic framework model describing the extent and thickness of hydrogeologic units in the Matanuska-Susitna Valley. The hydrogeologic framework model synthesizes existing maps of surficial geology and conceptual geochronologies developed in the study area with the distribution of lithologies encountered in hundreds of boreholes. The geologic modeling package Geological Surveying and Investigation in Three Dimensions (GSI3D) was used to construct the hydrogeologic framework model. In addition to characterizing the hydrogeologic framework, major groundwater-budget components were quantified using several different techniques. A land-surface model known as the Deep Percolation Model was used to estimate in-place groundwater recharge across the study area. This model incorporates data on topography, soils, vegetation, and climate. Model-simulated surface runoff was consistent with observed streamflow at U.S. Geological Survey streamgages. Groundwater withdrawals were estimated on the basis of records from major water suppliers during 2004-2010. Fluxes between groundwater and surface water were

  7. Revised model of regional groundwater flow in the Whiteshell research area

    International Nuclear Information System (INIS)

    Ophori, D.U.; Brown, A.; Chan, T.; Davison, C.C.; Gascoyne, M.; Scheier, N.W.; Stanchell, F.W.; Stevenson, D.R.

    1996-08-01

    Steady-state regional groundwater flow of the Whiteshell Research Area (WRA) has been simulated in order to evaluate alternate locations for a hypothetical nuclear fuel waste disposal vault that maximize the retention of vault contaminants in long, slow groundwater flow paths through the geosphere. A revised conceptual model of the hydrogeologic conditions was constructed using all the information obtained from field investigations at the WRA between 1977 and 1994. All the simulations were performed using AECL's three-dimensional finite element code, MOTIF. A base-case simulation was performed using average value estimates of hydraulic parameters obtained from the field data, and freshwater was assumed to occur in the entire groundwater flow region. The simulated freshwater heads did not compare favourably with the freshwater beads that were derived from the field data. The simulated equivalent freshwater heads for the final calibrated model compared reasonably well with measured heads in the network of boreholes at the WRA. The simulated recharge rate for the final model was 4.8 mm/a Most of the groundwater flow in the model occurred in local systems between ground surface and a depth of 1000 m. A particle tracking code, TRACK3D, was used to determine the pathways, travel times and exit locations of particles released from different depths in the groundwater velocity field of the calibrated model. The exit locations of these pathways were found to be controlled by the network of regional fracture zones in the model. These results were used to select a location for a hypothetical nuclear fuel waste disposal vault in the regional groundwater flow model that maximizes the retention of vault contaminants in long, slow groundwater flow paths. A smaller region of about 75 km 2 was identified around this location for the development of a local geosphere model. (author). 32 refs., 4 tabs., 29 figs

  8. An Investigation of Groundwater Flow on a Coastal Barrier using Multi Electrode Profiling

    DEFF Research Database (Denmark)

    Poulsen, Søren Erbs; Christensen, Steen; Rasmussen, Keld Rømer

    2008-01-01

    Preliminary geophysical and hydrogeological investigations indicate that multi-electrode profiling (MEP) can be used to monitor groundwater salinity on a coastal barrier where a shallow thin aquifer discharges to the North Sea. A monitoring system including five groups of piezometers and five MEP...... groundwater modeling we hope to be able to quantify how time varying recharge, tides, and storms hitting the barrier affect groundwater flow and discharge to the sea. At the conference we will present monitoring results from the winter and spring 2008....

  9. Groundwater Flow and Transport Model in Cecina Plain (Tuscany, Italy) using GIS processing

    OpenAIRE

    Riccardo Armellini; Elena Baldini; Dario Del Seppia; Fabrizio Franceschini; Natacha Gori; Stefano Menichetti; Stefano Tessitore

    2015-01-01

    This work provides a groundwater flow and transport model of trichlorethylene and tetrachlorethylene contamination in the Cecina’s coastal aquifer. The contamination analysis, with source located in the Poggio Gagliardo area (Montescudaio, Pisa), was necessary to optimize the groundwater monitoring and remediation design. The work was carried out in two phases: • design of a conceptual model of the aquifer using GIS analysis of many stratigraphic, chemical and hydrogeological data, collected ...

  10. Five-point Element Scheme of Finite Analytic Method for Unsteady Groundwater Flow

    Institute of Scientific and Technical Information of China (English)

    Xiang Bo; Mi Xiao; Ji Changming; Luo Qingsong

    2007-01-01

    In order to improve the finite analytic method's adaptability for irregular unit, by using coordinates rotation technique this paper establishes a five-point element scheme of finite analytic method. It not only solves unsteady groundwater flow equation but also gives the boundary condition. This method can be used to calculate the three typical questions of groundwater. By compared with predecessor's computed result, the result of this method is more satisfactory.

  11. Groundwater Flow Systems at the Nevada Test Site, Nevada: A Synthesis of Potentiometric Contours, Hydrostratigraphy, and Geologic Structures

    Energy Technology Data Exchange (ETDEWEB)

    Fenelon, Joseph M.; Sweetkind, Donald S.; Laczniak, Randell J.

    2010-01-25

    Contaminants introduced into the subsurface of the Nevada Test Site by underground nuclear testing are of concern to the U.S. Department of Energy and regulators responsible for protecting human health and safety. The potential for contaminant movement away from the underground test areas and into the accessible environment is greatest by groundwater transport. The primary hydrologic control on this transport is evaluated and examined through a series of contour maps developed to represent the hydraulic-head distribution within each of the major aquifers underlying the area. Aquifers were identified and their extents delineated by merging and analyzing multiple hydrostratigraphic framework models developed by other investigators from existing geologic information. A map of the hydraulic-head distribution in each major aquifer was developed from a detailed evaluation and assessment of available water-level measurements. Multiple spreadsheets that accompany this report provide pertinent water-level and geologic data by well or drill hole. Aquifers are mapped and discussed in general terms as being one of two types: alluvial-volcanic, or carbonate. Both aquifer types are subdivided and mapped as independent regional and local aquifers, based on the continuity of their component rock. Groundwater-flow directions, approximated from potentiometric contours that were developed from the hydraulic-head distribution, are indicated on the maps and discussed for each of the regional aquifers and for selected local aquifers. Hydraulic heads vary across the study area and are interpreted to range in altitude from greater than 5,000 feet in a regional alluvial-volcanic aquifer beneath a recharge area in the northern part of the study area to less than 2,300 feet in regional alluvial-volcanic and carbonate aquifers in the southwestern part of the study area. Flow directions throughout the study area are dominantly south-southwest with some local deviations. Vertical hydraulic

  12. Groundwater Flow Systems at the Nevada Test Site, Nevada: A Synthesis of Potentiometric Contours, Hydrostratigraphy, and Geologic Structures

    Science.gov (United States)

    Fenelon, Joseph M.; Sweetkind, Donald S.; Laczniak, Randell J.

    2010-01-01

    Contaminants introduced into the subsurface of the Nevada Test Site by underground nuclear testing are of concern to the U.S. Department of Energy and regulators responsible for protecting human health and safety. The potential for contaminant movement away from the underground test areas and into the accessible environment is greatest by groundwater transport. The primary hydrologic control on this transport is evaluated and examined through a series of contour maps developed to represent the hydraulic-head distribution within each of the major aquifers underlying the area. Aquifers were identified and their extents delineated by merging and analyzing multiple hydrostratigraphic framework models developed by other investigators from existing geologic information. A map of the hydraulic-head distribution in each major aquifer was developed from a detailed evaluation and assessment of available water-level measurements. Multiple spreadsheets that accompany this report provide pertinent water-level and geologic data by well or drill hole. Aquifers are mapped and discussed in general terms as being one of two types: alluvial-volcanic, or carbonate. Both aquifer types are subdivided and mapped as independent regional and local aquifers, based on the continuity of their component rock. Groundwater-flow directions, approximated from potentiometric contours that were developed from the hydraulic-head distribution, are indicated on the maps and discussed for each of the regional aquifers and for selected local aquifers. Hydraulic heads vary across the study area and are interpreted to range in altitude from greater than 5,000 feet in a regional alluvial-volcanic aquifer beneath a recharge area in the northern part of the study area to less than 2,300 feet in regional alluvial-volcanic and carbonate aquifers in the southwestern part of the study area. Flow directions throughout the study area are dominantly south-southwest with some local deviations. Vertical hydraulic

  13. MODFLOW-2000, The U.S. Geological Survey Modular Ground-Water Model - User Guide to Modularization Concepts and the Ground-Water Flow Process

    Science.gov (United States)

    Harbaugh, Arlen W.; Banta, Edward R.; Hill, Mary C.; McDonald, Michael G.

    2000-01-01

    MODFLOW is a computer program that numerically solves the three-dimensional ground-water flow equation for a porous medium by using a finite-difference method. Although MODFLOW was designed to be easily enhanced, the design was oriented toward additions to the ground-water flow equation. Frequently there is a need to solve additional equations; for example, transport equations and equations for estimating parameter values that produce the closest match between model-calculated heads and flows and measured values. This report documents a new version of MODFLOW, called MODFLOW-2000, which is designed to accommodate the solution of equations in addition to the ground-water flow equation. This report is a user's manual. It contains an overview of the old and added design concepts, documents one new package, and contains input instructions for using the model to solve the ground-water flow equation.

  14. Complexity in the validation of ground-water travel time in fractured flow and transport systems

    International Nuclear Information System (INIS)

    Davies, P.B; Hunter, R.L.; Pickens, J.F.

    1991-02-01

    Ground-water travel time is a widely used concept in site assessment for radioactive waste disposal. While ground-water travel time was originally conceived to provide a simple performance measure for evaluating repository sites, its definition in many flow and transport environments is ambiguous. The US Department of Energy siting guidelines (10 CFR 960) define ground-water travel time as the time required for a unit volume of water to travel between two locations, calculated by dividing travel-path length by the quotient of average ground-water flux and effective porosity. Defining a meaningful effective porosity in a fractured porous material is a significant problem. Although the Waste Isolation Pilot Plant (WIPP) is not subject to specific requirements for ground-water travel time, travel times have been computed under a variety of model assumptions. Recently completed model analyses for WIPP illustrate the difficulties in applying a ground-water travel-time performance measure to flow and transport in fractured, fully saturated flow systems. 12 refs., 4 figs

  15. First status report on regional ground-water flow modeling for Vacherie Dome, Louisiana

    International Nuclear Information System (INIS)

    1986-07-01

    Regional ground-water flow within the principal geohydrologic units in the vicinity of Vacherie Dome, Louisiana is evaluated by developing a conceptual model of the flow regime within these units and testing the model using a three-dimensional, finite-difference flow code (SWENT). Semiquantitative sensitivity analyses (a limited parametric study) are conducted to define the system responses to changes in the conceptual model, particularly in regard to the geohydrologic properties. All steps leading to the final results and conclusions are incorporated in this report. The available data utilized in this study are summarized. The conceptual model is defined in terms of the areal and vertical averaging of lithologic units, aquifer properties, and hydrologic boundary conditions. The simulated ground-water flow fields are described with potentiometric surfaces, areas of upward and downward flow across aquitards, tables summarizing the horizontal and vertical volumetric flows through the principal units, ground-water travel times and paths, and Darcy velocities within specified finite-difference blocks. The reported work is the first stage of an ongoing evaluation of Vacherie Dome as a potential repository for high-level radioactive wastes. The results and conclusions should thus be considered preliminary and subject to modification with the collection of additional data. However, the report does provide a useful basis for describing the sensitivity of the conceptualization of ground-water flow to parameterization and, to a lesser extent, the uncertainties in the present conceptualization. 34 refs., 57 figs., 19 tabs

  16. Regional groundwater flow and tritium transport modeling and risk assessment of the underground test area, Nevada Test Site, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    None

    1997-10-01

    The groundwater flow system of the Nevada Test Site and surrounding region was evaluated to estimate the highest potential current and near-term risk to the public and the environment from groundwater contamination downgradient of the underground nuclear testing areas. The highest, or greatest, potential risk is estimated by assuming that several unusually rapid transport pathways as well as public and environmental exposures all occur simultaneously. These conservative assumptions may cause risks to be significantly overestimated. However, such a deliberate, conservative approach ensures that public health and environmental risks are not underestimated and allows prioritization of future work to minimize potential risks. Historical underground nuclear testing activities, particularly detonations near or below the water table, have contaminated groundwater near testing locations with radioactive and nonradioactive constituents. Tritium was selected as the contaminant of primary concern for this phase of the project because it is abundant, highly mobile, and represents the most significant contributor to the potential radiation dose to humans for the short term. It was also assumed that the predicted risk to human health and the environment from tritium exposure would reasonably represent the risk from other, less mobile radionuclides within the same time frame. Other contaminants will be investigated at a later date. Existing and newly collected hydrogeologic data were compiled for a large area of southern Nevada and California, encompassing the Nevada Test Site regional groundwater flow system. These data were used to develop numerical groundwater flow and tritium transport models for use in the prediction of tritium concentrations at hypothetical human and ecological receptor locations for a 200-year time frame. A numerical, steady-state regional groundwater flow model was developed to serve as the basis for the prediction of the movement of tritium from the

  17. Structural Controls on Groundwater Flow in Basement Terrains: Geophysical, Remote Sensing, and Field Investigations in Sinai

    KAUST Repository

    Mohamed, Lamees

    2015-07-09

    An integrated [very low frequency (VLF) electromagnetic, magnetic, remote sensing, field, and geographic information system (GIS)] study was conducted over the basement complex in southern Sinai (Feiran watershed) for a better understanding of the structural controls on the groundwater flow. The increase in satellite-based radar backscattering values following a large precipitation event (34 mm on 17–18 January 2010) was used to identify water-bearing features, here interpreted as preferred pathways for surface water infiltration. Findings include: (1) spatial analysis in a GIS environment revealed that the distribution of the water-bearing features (conductive features) corresponds to that of fractures, faults, shear zones, dike swarms, and wadi networks; (2) using VLF (43 profiles), magnetic (7 profiles) techniques, and field observations, the majority (85 %) of the investigated conductive features were determined to be preferred pathways for groundwater flow; (3) northwest–southeast- to north–south-trending conductive features that intersect the groundwater flow (southeast to northwest) at low angles capture groundwater flow, whereas northeast–southwest to east–west features that intersect the flow at high angles impound groundwater upstream and could provide potential productive well locations; and (4) similar findings are observed in central Sinai: east–west-trending dextral shear zones (Themed and Sinai Hinge Belt) impede south to north groundwater flow as evidenced by the significant drop in hydraulic head (from 467 to 248 m above mean sea level) across shear zones and by reorientation of regional flow (south–north to southwest–northeast). The adopted integrated methodologies could be readily applied to similar highly fractured basement arid terrains elsewhere. © 2015 Springer Science+Business Media Dordrecht

  18. Radionuclide cisternography

    International Nuclear Information System (INIS)

    Song, H.H.

    1980-01-01

    The purpose of this thesis is to show that radionuclide cisternography makes an essential contribution to the investigation of cerebrospinal fluid (CSF) dynamics, especially for the investigation of hydrocephalus. The technical details of radionuclide cisternography are discussed, followed by a description of the normal and abnormal radionuclide cisternograms. The dynamics of CFS by means of radionuclide cisternography were examined in 188 patients in whom some kind of hydrocephalus was suspected. This study included findings of anomalies associated with hydrocephalus in a number of cases, such as nasal liquorrhea, hygromas, leptomeningeal or porencephalic cysts. The investigation substantiates the value of radionuclide cisternography in the diagnosis of disturbances of CSF flow. The retrograde flow of radiopharmaceutical into the ventricular system (ventricular reflux) is an abnormal phenomenon indicating the presence of communicating hydrocephalus. (Auth.)

  19. Application of MODFLOW and geographic information system to groundwater flow simulation in North China Plain, China

    Science.gov (United States)

    Wang, Shiqin; Shao, Jingli; Song, Xianfang; Zhang, Yongbo; Huo, Zhibin; Zhou, Xiaoyuan

    2008-10-01

    MODFLOW is a groundwater modeling program. It can be compiled and remedied according to the practical applications. Because of its structure and fixed data format, MODFLOW can be integrated with Geographic Information Systems (GIS) technology for water resource management. The North China Plain (NCP), which is the politic, economic and cultural center of China, is facing with water resources shortage and water pollution. Groundwater is the main water resource for industrial, agricultural and domestic usage. It is necessary to evaluate the groundwater resources of the NCP as an entire aquifer system. With the development of computer and internet information technology it is also necessary to integrate the groundwater model with the GIS technology. Because the geological and hydrogeological data in the NCP was mainly in MAPGIS format, the powerful function of GIS of disposing of and analyzing spatial data and computer languages such as Visual C and Visual Basic were used to define the relationship between the original data and model data. After analyzing the geological and hydrogeological conditions of the NCP, the groundwater flow numerical simulation modeling was constructed with MODFLOW. On the basis of GIS, a dynamic evaluation system for groundwater resources under the internet circumstance was completed. During the process of constructing the groundwater model, a water budget was analyzed, which showed a negative budget in the NCP. The simulation period was from 1 January 2002 to 31 December 2003. During this period, the total recharge of the groundwater system was 49,374 × 106 m3 and the total discharge was 56,530 × 106 m3 the budget deficit was -7,156 × 106 m3. In this integrated system, the original data including graphs and attribution data could be stored in the database. When the process of evaluating and predicting groundwater flow was started, these data were transformed into files that the core program of MODFLOW could read. The calculated water

  20. Human impacts on groundwater flow and contamination deduced by multiple isotopes in Seoul City, South Korea

    Energy Technology Data Exchange (ETDEWEB)

    Hosono, Takahiro, E-mail: hosono@chikyu.ac.jp [Research Institute for Humanity and Nature, 457-4 Motoyama Kamigamo, Kita-ku, Kyoto 603-8047 (Japan); Ikawa, Reo, E-mail: r_ikawa@es.sci.kumamoto-u.ac.jp [Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555 (Japan); Shimada, Jun, E-mail: jshimada@sci.kumamoto-u.ac.jp [Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555 (Japan); Nakano, Takanori, E-mail: nakanot@chikyu.ac.jp [Research Institute for Humanity and Nature, 457-4 Motoyama Kamigamo, Kita-ku, Kyoto 603-8047 (Japan); Saito, Mitsuyo, E-mail: misaito@hiroshima-u.ac.jp [Graduate School of Biosphere Science, Hiroshima University, 1-7-1, Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8521 (Japan); Onodera, Shin-ichi, E-mail: sonodera@hiroshima-u.ac.jp [Graduate School of Integrated Arts and Sciences, Hiroshima University, 1-7-1, Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8521 (Japan); Lee, Kang-Kun, E-mail: kklee@snu.ac.kr [School of Earth and Environmental Science, Seoul National University, San 56-1, Shinrim-dong, Kwanak-gu, Seoul 151-747 (Korea, Republic of); Taniguchi, Makoto, E-mail: makoto@chikyu.ac.jp [Research Institute for Humanity and Nature, 457-4 Motoyama Kamigamo, Kita-ku, Kyoto 603-8047 (Japan)

    2009-04-15

    The influence of human activities on the flow system and contamination of groundwater were investigated in Seoul City, South Korea, one of the largest Asian cities, using a combination of isotopes ({delta}D, T, {delta}{sup 15}N, {delta}{sup 18}O, {delta}{sup 34}S, and {sup 87}Sr/{sup 86}Sr). Eighteen representative groundwater and river water samples, which were collected over a wide area of the city, were compared with previously reported data. The distribution of stable isotopes ({delta}D and {delta}{sup 18}O) with groundwater potential data shows that recharged groundwater from either the surrounding mountainous area as well as the Han River and other surface streams discharged towards the northern-central part of the city, where a subway tunnel pumping station is located. It is suggested from T values (3.3 to 5.8 T.U.) that groundwater was recharged in the last 30 to 40 years. The {delta}{sup 34}S and {delta}{sup 15}N of SO{sub 4}{sup 2-} and NO{sub 3}{sup -} data were efficiently used as indicators of contamination by human activities. These isotopes clarified that the contribution of anthropogenic contaminants i.e., industrial and household effluents, waste landfills, and fertilizers, are responsible for the enrichment by SO{sub 4}{sup 2-} (> 30 ppm as SO{sub 4}{sup 2-}) and NO{sub 3}{sup -} (> 20 ppm as NO{sub 3}{sup -}) of groundwater. The {sup 87}Sr/{sup 86}Sr values of groundwater vary (0.71326 to 0.75058) in accordance with the host rocks of different origins. Mineral elements such as Ca are also suggested to be derived naturally from rocks. The groundwater under Seoul City is greatly affected by transportation of pollutants along the groundwater flow controlled by subway tunnel pumping, contributing to the degradation of water quality in urbanized areas.

  1. Human impacts on groundwater flow and contamination deduced by multiple isotopes in Seoul City, South Korea

    International Nuclear Information System (INIS)

    Hosono, Takahiro; Ikawa, Reo; Shimada, Jun; Nakano, Takanori; Saito, Mitsuyo; Onodera, Shin-ichi; Lee, Kang-Kun; Taniguchi, Makoto

    2009-01-01

    The influence of human activities on the flow system and contamination of groundwater were investigated in Seoul City, South Korea, one of the largest Asian cities, using a combination of isotopes (δD, T, δ 15 N, δ 18 O, δ 34 S, and 87 Sr/ 86 Sr). Eighteen representative groundwater and river water samples, which were collected over a wide area of the city, were compared with previously reported data. The distribution of stable isotopes (δD and δ 18 O) with groundwater potential data shows that recharged groundwater from either the surrounding mountainous area as well as the Han River and other surface streams discharged towards the northern-central part of the city, where a subway tunnel pumping station is located. It is suggested from T values (3.3 to 5.8 T.U.) that groundwater was recharged in the last 30 to 40 years. The δ 34 S and δ 15 N of SO 4 2- and NO 3 - data were efficiently used as indicators of contamination by human activities. These isotopes clarified that the contribution of anthropogenic contaminants i.e., industrial and household effluents, waste landfills, and fertilizers, are responsible for the enrichment by SO 4 2- (> 30 ppm as SO 4 2- ) and NO 3 - (> 20 ppm as NO 3 - ) of groundwater. The 87 Sr/ 86 Sr values of groundwater vary (0.71326 to 0.75058) in accordance with the host rocks of different origins. Mineral elements such as Ca are also suggested to be derived naturally from rocks. The groundwater under Seoul City is greatly affected by transportation of pollutants along the groundwater flow controlled by subway tunnel pumping, contributing to the degradation of water quality in urbanized areas.

  2. Evaluation of in situ sulfate reduction as redox buffer capacity in groundwater flow path

    International Nuclear Information System (INIS)

    Ioka, Seiichiro; Iwatsuki, Teruki; Amano, Yuki; Furue, Ryoji

    2007-01-01

    For safety assessment of geological isolation, it is important to evaluate in situ redox buffer capacity in high-permeability zone as groundwater flow path. The study evaluated in situ sulfate reduction as redox buffer capacity in the conglomerate bedding in Toki Lignite-bearing Formation, which occurs at the lowest part of sedimentary rocks overlying basement granite. The bedding plays an important role as the main groundwater flow path. The result showed that in situ redox buffer capacity in the conglomerate bedding has been identified on first nine months, whereas in the following period the redox buffer capacity has not been identified for about fifteen months. This will be caused by the bedding became inappropriate for microbial survival as the organic matter which is needfuel for microbial activity was consumed. Thus, there will be limited redox buffer capacity in groundwater flow path even in formation including organic matter-bearing layer. (author)

  3. MEASUREMENT OF RADIONUCLIDES USING ION CHROMATOGRAPHY AND FLOW-CELL SCINTILLATION COUNTING WITH PULSE SHAPE DISCRIMINATION

    International Nuclear Information System (INIS)

    Fjeld, R. A.; DeVol, T.A.; Leyba, J.D.

    2000-01-01

    Radiological characterization and monitoring is an important component of environmental management activities throughout the Department of Energy complex. Gamma-ray spectroscopy is the technology most often used for the detection of radionuclides. However, radionuclides which cannot easily be detected by gamma-ray spectroscopy, such as pure beta emitters and transuranics, pose special problems because their quantification generally requires labor intensive radiochemical separations procedures that are time consuming and impractical for field applications. This project focused on a technology for measuring transuranics and pure beta emitters relatively quickly and has the potential of being field deployable. The technology combines ion exchange liquid chromatography and on-line alpha/beta pulse shape discriminating scintillation counting to produce simultaneous alpha and beta chromatograms. The basic instrumentation upon which the project was based was purchased in the early 1990's. In its original commercial form, the instrumentation was capable of separating select activation/fission products in ionic forms from relatively pure aqueous samples. We subsequently developed the capability of separating and detecting actinides (thorium, uranium, neptunium, plutonium, americium, and curium) in less than 30 minutes (Reboul, 1993) and realized that the potential time savings over traditional radiochemical methods for isolating some of these radionuclides was significant. However, at that time, the technique had only been used for radionuclide concentrations that were considerably above environmental levels and for aqueous samples of relatively high chemical purity. For the technique to be useful in environmental applications, development work was needed in lowering detection limits; to be useful in applications involving non-aqueous matrices such as soils and sludges or complex aqueous matrices such as those encountered in waste samples, development work was needed in

  4. Site-scale groundwater flow modelling of Aberg

    Energy Technology Data Exchange (ETDEWEB)

    Walker, D. [Duke Engineering and Services (United States); Gylling, B. [Kemakta Konsult AB, Stockholm (Sweden)

    1998-12-01

    The Swedish Nuclear Fuel and Waste Management Company (SKB) SR 97 study is a comprehensive performance assessment illustrating the results for three hypothetical repositories in Sweden. In support of SR 97, this study examines the hydrogeologic modelling of the hypothetical site called Aberg, which adopts input parameters from the Aespoe Hard Rock Laboratory in southern Sweden. This study uses a nested modelling approach, with a deterministic regional model providing boundary conditions to a site-scale stochastic continuum model. The model is run in Monte Carlo fashion to propagate the variability of the hydraulic conductivity to the advective travel paths from representative canister locations. A series of variant cases addresses uncertainties in the inference of parameters and the boundary conditions. The study uses HYDRASTAR, the SKB stochastic continuum groundwater modelling program, to compute the heads, Darcy velocities at each representative canister position and the advective travel times and paths through the geosphere. The nested modelling approach and the scale dependency of hydraulic conductivity raise a number of questions regarding the regional to site-scale mass balance and the method`s self-consistency. The transfer of regional heads via constant head boundaries preserves the regional pattern recharge and discharge in the site-scale model, and the regional to site-scale mass balance is thought to be adequate. The upscaling method appears to be approximately self-consistent with respect to the median performance measures at various grid scales. A series of variant cases indicates that the study results are insensitive to alternative methods on transferring boundary conditions from the regional model to the site-scale model. The flow paths, travel times and simulated heads appear to be consistent with on-site observations and simple scoping calculations. The variabilities of the performance measures are quite high for the Base Case, but the

  5. Site-scale groundwater flow modelling of Aberg

    International Nuclear Information System (INIS)

    Walker, D.; Gylling, B.

    1998-12-01

    The Swedish Nuclear Fuel and Waste Management Company (SKB) SR 97 study is a comprehensive performance assessment illustrating the results for three hypothetical repositories in Sweden. In support of SR 97, this study examines the hydrogeologic modelling of the hypothetical site called Aberg, which adopts input parameters from the Aespoe Hard Rock Laboratory in southern Sweden. This study uses a nested modelling approach, with a deterministic regional model providing boundary conditions to a site-scale stochastic continuum model. The model is run in Monte Carlo fashion to propagate the variability of the hydraulic conductivity to the advective travel paths from representative canister locations. A series of variant cases addresses uncertainties in the inference of parameters and the boundary conditions. The study uses HYDRASTAR, the SKB stochastic continuum groundwater modelling program, to compute the heads, Darcy velocities at each representative canister position and the advective travel times and paths through the geosphere. The nested modelling approach and the scale dependency of hydraulic conductivity raise a number of questions regarding the regional to site-scale mass balance and the method's self-consistency. The transfer of regional heads via constant head boundaries preserves the regional pattern recharge and discharge in the site-scale model, and the regional to site-scale mass balance is thought to be adequate. The upscaling method appears to be approximately self-consistent with respect to the median performance measures at various grid scales. A series of variant cases indicates that the study results are insensitive to alternative methods on transferring boundary conditions from the regional model to the site-scale model. The flow paths, travel times and simulated heads appear to be consistent with on-site observations and simple scoping calculations. The variabilities of the performance measures are quite high for the Base Case, but the

  6. The Effects of Different Scales of Topographic Variation on Shallow Groundwater Flow in an Arctic Watershed

    Science.gov (United States)

    Nicholaides, K. D.; O'Connor, M.; Cardenas, M. B.; Neilson, B. T.; Kling, G. W.

    2017-12-01

    Arctic permafrost degradation is occurring as global temperatures increase. In addition, recent evidence shows the Arctic is shifting from a sink to a source of carbon to the atmosphere. However, the cause of this shift is unclear, as is the role of newly exposed organic soil carbon leaching into groundwater and transported to surface water. This soil carbon may be photo-oxidized to CO2 or microbially respired to CO2 and methane, adding greenhouse gases to the atmosphere. The fate of carbon in permafrost is largely governed by the length of time spent in transport and the surface or subsurface route it follows. However, groundwater flow regimes within shallow active layer aquifers overlying permafrost is poorly understood. We determined to what extent smaller scale topography influences groundwater flow and residence times in arctic tundra. The study focused on Imnavait Creek watershed, a 1st-order drainage on the Alaskan North Slope underlain by continuous permafrost. We used direct measurements of hydraulic conductivities and porosities over a range of depths as well as basin-scale topography to develop vertically-integrated groundwater flow models. By systematically decreasing the amount of topographic detail, we were able to compare the influence of more detailed topography on groundwater flow estimates. Scaling up this model will be a useful tool in understanding how larger basins in permafrost will respond to future climate change and their contributions to greenhouse gases in the atmosphere.

  7. Groundwater flow in the Venice lagoon and remediation of the Porto Marghera industrial area (Italy)

    Science.gov (United States)

    Beretta, Giovanni Pietro; Terrenghi, Jacopo

    2017-05-01

    This study aims to determine the groundwater flow in a large area of the Venice (northeast Italy) lagoon that is under great anthropogenic pressure, which is influencing the regional flow in the surficial aquifer (about 30 m depth). The area presents several elements that condition the groundwater flow: extraction by means of drainage pumps and wells; tidal fluctuation; impermeable barriers that define part of the coastline, rivers and artificial channels; precipitation; recharge, etc. All the elements were studied separately, and then they were brought together in a numerical groundwater flow model to estimate the impact of each one. Identification of the impact of each element will help to optimise the characteristics of the Porto Marghera remediation systems. Longstanding industrial activity has had a strong impact on the soil and groundwater quality, and expensive and complex emergency remediation measures in problematic locations have been undertaken to ensure the continuity of industrial and maritime activities. The land reclamation and remediation works withdraw 56-74% of the water budget, while recharge from the river accounts for about 21-48% of the input. Only 21-42% of groundwater in the modelled area is derived from natural recharge sources, untouched by human activity. The drop of the piezometric level due to the realization of the upgradient impermeable barrier can be counteracted with the reduction of the pumping rate of the remediation systems.

  8. An analytical study on groundwater flow in drainage basins with horizontal wells

    Science.gov (United States)

    Wang, Jun-Zhi; Jiang, Xiao-Wei; Wan, Li; Wang, Xu-Sheng; Li, Hailong

    2014-06-01

    Analytical studies on release/capture zones are often limited to a uniform background groundwater flow. In fact, for basin-scale problems, the undulating water table would lead to the development of hierarchically nested flow systems, which are more complex than a uniform flow. Under the premise that the water table is a replica of undulating topography and hardly influenced by wells, an analytical solution of hydraulic head is derived for a two-dimensional cross section of a drainage basin with horizontal injection/pumping wells. Based on the analytical solution, distributions of hydraulic head, stagnation points and flow systems (including release/capture zones) are explored. The superposition of injection/pumping wells onto the background flow field leads to the development of new internal stagnation points and new flow systems (including release/capture zones). Generally speaking, the existence of n injection/pumping wells would result in up to n new internal stagnation points and up to 2n new flow systems (including release/capture zones). The analytical study presented, which integrates traditional well hydraulics with the theory of regional groundwater flow, is useful in understanding basin-scale groundwater flow influenced by human activities.

  9. Understanding large scale groundwater flow to aid in repository siting

    International Nuclear Information System (INIS)

    Davison, C.C.; Brown, A.; Gascoyne, M.; Stevenson, D.R.; Ophori, D.U.

    1996-01-01

    Atomic Energy of Canada Limited (AECL) with support from Ontario Hydro has developed a concept for the safe disposal of Canada's nuclear fuel waste in a deep (500 to 1000 m) mined repository in plutonic rocks of the Canadian Shield. The disposal concept involves the use of multiple engineered and natural barriers to ensure long-term safety. The geosphere, comprised of the enclosing rock mass and the groundwater which occurs in cracks and pores in the rock, is expected to serve as an important natural barrier to the release and migration of wastes from the engineered repository. Although knowledge of the physical and chemical characteristics of the groundwater in the rock at potential repository sites is needed to help design the engineered barriers of the repository it can also be used to aid in repository siting, to take greater advantage of natural conditions in the geosphere to enhance its role as a barrier in the overall disposal system

  10. Measurement of radionuclides using ion chromatography and flow-cell scintillation counting with pulse shape discrimination

    International Nuclear Information System (INIS)

    DeVol, T.A.; Fjeld, R.A.

    1995-01-01

    The use of ion chromatography (IC) for radiochemical separations is a well established technique. IC is commonly used in routine environmental monitoring applications as well as in specialized research applications. Typical usage involves the separation of a single radionuclide from the non-radioactive constituents. During the past decade, a limited amount of research has been conducted using automated IC systems in actinide separation applications (e.g.). More recently, separation procedures for common non-gamma emitting activation and fission products were developed utilizing a high performance liquid chromatography (HPLC) system. In addition, a separation procedure for six common actinides has been developed using a HPLC system. These latter systems used on-line flow-cell detectors for quantification of the radioactive constituents of the effluent stream

  11. Potential Groundwater Recharge and the Effects of Soil Heterogeneity on Flow at Two Radioactive Waste Management Sites at the Nevada Test Site

    International Nuclear Information System (INIS)

    Yucel, V.; Levitt, D. G.

    2001-01-01

    Two low-level Radioactive Waste Management Sites (RWMSs), consisting of shallow land burial disposal units at the Nevada Test Site (NTS), are managed by Bechtel Nevada for the U.S. Department of Energy, National Nuclear Security Administration. The NTS has an arid climate with annual average precipitation of about 17 cm at the Area 3 RWMS and about 13 cm at the Area 5 RWMS. The vadose zone is about 490 m thick at the Area 3 RWMS, and about 235 m thick at the Area 5 RWMS. Numerous studies indicate that under current climatic conditions, there is generally no groundwater recharge at these sites. Groundwater recharge may occur at isolated locations surrounding the RWMSs, such as in large drainage washes. However, groundwater recharge scenarios (and radionuclide transport) at the RWMSs are modeled in support of Performance Assessment (PA) documents required for operation of each RWMS. Recharge scenarios include conditions of massive subsidence and flooding, and recharge resulting from deep infiltration through bare-soil waste covers. This paper summarizes the groundwater recharge scenarios and travel time estimates that have been conducted in support of the PAs, and examines the effects of soil hydraulic property heterogeneity on flow

  12. Reconstructing the groundwater flow in the Baltic Basin during the Last glaciation

    Science.gov (United States)

    Saks, T.; Sennikovs, J.; Timuhins, A.; Kalvāns, A.

    2012-04-01

    In last decades it has been discussed that most large ice sheets tend to reside on warm beds even in harsh clima tic conditions and subglacial melting occurs due to geothermal heat flow and deformation heat of the ice flow. However the subglacial groundwater recharge and flow conditions have been addressed in only few studies. The aim of this study is to establish the groundwater flow pattern in the Baltic Basin below the Scandinavian ice sheet during the Late Weichselian glaciation. The calculation results are compared to the known distribution of the groundwater body of the glacial origin found in Cambrian - Vendian (Cm-V) aquifer in the Northern Estonia which is believed to have originated as a result of subglacial meltwater infiltration during the reoccurring glaciations. Steady state regional groundwater flow model of the Baltic Basin was used to simulate the groundwater flow beneath the ice sheet with its geometry adjusted to reflect the subglacial topography. Ice thickness modelling data (Argus&Peltier, 2010) was used for the setup of the boundary conditions: the meltwater pressure at the ice bed was assumed equal to the overlying ice mass. The modelling results suggest two main recharge areas of the Cm-V aquifer system, and reversed groundwater flow that persisted for at least 14 thousand years. Model results show that the groundwater flow velocities in the Cm-V aquifer in the recharge area in N-Estonia beneath the ice sheet exceeded the present velocities by a factor of 10 on average. The calculated meltwater volume recharged into the Cm-V aquifer system during the Late Weichselian corresponds roughly to the estimated, however, considering the fact, that the study area has been glaciated at least 4 times this is an overestimation. The modeling results attest the hypothesis of light dO18 groundwater glacial origin in the Cm-V aquifer system, however the volumes, timing and processes involved in the meltwater intrusion are yet to be explored. This study was

  13. Numerical Simulation of Groundwater Flow at Kori Nuclear Power Plant Site

    International Nuclear Information System (INIS)

    Sohn, Wook; Sohn, Soon Whan; Chon, Chul Min; Kim, Kue Youn

    2010-01-01

    Recently, the understanding of hydrogeological characteristics of nuclear power sites is getting more importance with increasing public concerns over the environment since such understanding is essential for an environmentally friendly operation of plants. For such understanding, the prediction of groundwater flow pattern onsite plays the most critical role since it is the most dynamic of the factors to be considered. In this study, the groundwater flow at the Kori Plant 1 site has been simulated numerically with aim of providing fundamental information needed for improving the understanding of the hydrogeological characteristics of the site

  14. Groundwater flow simulation on local scale. Setting boundary conditions of groundwater flow simulation on site scale model in the step 4

    International Nuclear Information System (INIS)

    Onoe, Hironori; Saegusa, Hiromitsu; Ohyama, Takuya

    2007-03-01

    Japan Atomic Energy Agency has been conducting a wide range of geoscientific research in order to build a foundation for multidisciplinary studies of the deep geological environment as a basis of research and development for geological disposal of nuclear wastes. Ongoing geoscientific research programs include the Regional Hydrogeological Study (RHS) project and Mizunami Underground Research Laboratory (MIU) project in the Tono region, Gifu Prefecture. The main goal of these projects is to establish comprehensive techniques for investigation, analysis, and assessment of the deep geological at several spatial scales. The RHS project is a Local scale study for understanding the groundwater flow system from the recharge area to the discharge area. The Surface-based Investigation Phase of the MIU project is a Site scale study for understanding the deep geological environment immediately surrounding the MIU construction site using a multiphase, iterative approach. In this study, the hydrogeological modeling and groundwater flow simulation on Local scale were carried out in order to set boundary conditions of the Site scale model based on the data obtained from surface-based investigations in the Step4 in Site scale of the MIU project. As a result of the study, boundary conditions for groundwater flow simulation on the Site scale model of the Step4 could be obtained. (author)

  15. Groundwater flow analysis on local scale. Setting boundary conditions of groundwater flow analysis on site scale model in the former part of the step 3

    International Nuclear Information System (INIS)

    Onoe, Hironori; Saegusa, Hiromitsu

    2005-07-01

    Japan Nuclear Cycle Development Institute has been conducting a wide range of geoscientific research in order to build a foundation for multidisciplinary studies of the deep geological environment as a basis of research and development for geological disposal of nuclear wastes. Ongoing geoscientific research programs include the Regional Hydrogeological Study (RHS) project and Mizunami Underground Research Laboratory (MIU) project in the Tono region, Gifu Prefecture. The main goal of these projects is to establish comprehensive techniques for investigation, analysis, and assessment of the deep geological environment at several spatial scales. The RHS project is a local scale study for understanding the groundwater flow system from the recharge area to the discharge area. The Surface-based Investigation Phase of the MIU project is a mainly site scale study for understanding the deep geological environment immediately surrounding the MIU construction site using a multiphase, iterative approach. In this study, the hydrogeological modeling and groundwater flow analysis on the Local scale were carried out in order to set boundary conditions of the site scale model based on the data obtained from surface-based investigations in the former part of the Step 3 in site scale of the MIU project. As a result of the study, the uncertainty of hydrogeological model of the local scale and boundary conditions for the site scale model is decreased as stepwise investigation, and boundary conditions for groundwater flow analysis on the site scale model for the former part of the Step 3 could be obtained. (author)

  16. Incorporation of sedimentological data into a calibrated groundwater flow and transport model

    International Nuclear Information System (INIS)

    Williams, N.J.; Young, S.C.; Barton, D.H.; Hurst, B.T.

    1997-01-01

    Analysis suggests that a high hydraulic conductivity (K) zone is associated with a former river channel at the Portsmouth Gaseous Diffusion Plant (PORTS). A two-dimensional (2-D) and three-dimensional (3-D) groundwater flow model was developed base on a sedimentological model to demonstrate the performance of a horizontal well for plume capture. The model produced a flow field with magnitudes and directions consistent with flow paths inferred from historical trichloroethylene (TCE) plume data. The most dominant feature affecting the well's performance was preferential high- and low-K zones. Based on results from the calibrated flow and transport model, a passive groundwater collection system was designed and built. Initial flow rates and concentrations measured from a gravity-drained horizontal well agree closely to predicted values

  17. Slope instability in complex 3D topography promoted by convergent 3D groundwater flow

    Science.gov (United States)

    Reid, M. E.; Brien, D. L.

    2012-12-01

    Slope instability in complex topography is generally controlled by the interaction between gravitationally induced stresses, 3D strengths, and 3D pore-fluid pressure fields produced by flowing groundwater. As an example of this complexity, coastal bluffs sculpted by landsliding commonly exhibit a progression of undulating headlands and re-entrants. In this landscape, stresses differ between headlands and re-entrants and 3D groundwater flow varies from vertical rainfall infiltration to lateral groundwater flow on lower permeability layers with subsequent discharge at the curved bluff faces. In plan view, groundwater flow converges in the re-entrant regions. To investigate relative slope instability induced by undulating topography, we couple the USGS 3D limit-equilibrium slope-stability model, SCOOPS, with the USGS 3D groundwater flow model, MODFLOW. By rapidly analyzing the stability of millions of potential failures, the SCOOPS model can determine relative slope stability throughout the 3D domain underlying a digital elevation model (DEM), and it can utilize both fully 3D distributions of pore-water pressure and material strength. The two models are linked by first computing a groundwater-flow field in MODFLOW, and then computing stability in SCOOPS using the pore-pressure field derived from groundwater flow. Using these two models, our analyses of 60m high coastal bluffs in Seattle, Washington showed augmented instability in topographic re-entrants given recharge from a rainy season. Here, increased recharge led to elevated perched water tables with enhanced effects in the re-entrants owing to convergence of groundwater flow. Stability in these areas was reduced about 80% compared to equivalent dry conditions. To further isolate these effects, we examined groundwater flow and stability in hypothetical landscapes composed of uniform and equally spaced, oscillating headlands and re-entrants with differing amplitudes. The landscapes had a constant slope for both

  18. Research on radionuclide migration under subsurface geochemical conditions. JAERI/AECL Phase II Collaborative Program Year 1 (joint research)

    International Nuclear Information System (INIS)

    1998-11-01

    A radionuclide migration experiment program for fractured rocks was performed under the JAERI/AECL Phase-II Collaborative Program on research and development in radioactive waste management. The program started in the fiscal year 1993, as a five-year program consists of Quarried block radionuclide migration program, Speciation of long-lived radionuclides in groundwater, Isotopic hydrogeology and Groundwater flow model development. During the first year of the program (Program Year 1: March 18, 1994 - September 30, 1994), a plan was developed to take out granite blocks containing part of natural water-bearing fracture from the wall of the experimental gallery at the depth of 240 m, and literature reviews were done in the area of the speciation of long-lived radionuclides in groundwater, isotopic hydrogeology and the groundwater flow model development to proceed further work for the Program Year 2. (author)

  19. A Modified Groundwater Flow Model Using the Space Time Riemann-Liouville Fractional Derivatives Approximation

    Directory of Open Access Journals (Sweden)

    Abdon Atangana

    2014-01-01

    Full Text Available The notion of uncertainty in groundwater hydrology is of great importance as it is known to result in misleading output when neglected or not properly accounted for. In this paper we examine this effect in groundwater flow models. To achieve this, we first introduce the uncertainties functions u as function of time and space. The function u accounts for the lack of knowledge or variability of the geological formations in which flow occur (aquifer in time and space. We next make use of Riemann-Liouville fractional derivatives that were introduced by Kobelev and Romano in 2000 and its approximation to modify the standard version of groundwater flow equation. Some properties of the modified Riemann-Liouville fractional derivative approximation are presented. The classical model for groundwater flow, in the case of density-independent flow in a uniform homogeneous aquifer is reformulated by replacing the classical derivative by the Riemann-Liouville fractional derivatives approximations. The modified equation is solved via the technique of green function and the variational iteration method.

  20. Analytical Solutions of a Space-Time Fractional Derivative of Groundwater Flow Equation

    Directory of Open Access Journals (Sweden)

    Abdon Atangana

    2014-01-01

    Full Text Available The classical Darcy law is generalized by regarding the water flow as a function of a noninteger order derivative of the piezometric head. This generalized law and the law of conservation of mass are then used to derive a new equation for groundwater flow. Two methods including Frobenius and Adomian decomposition method are used to obtain an asymptotic analytical solution to the generalized groundwater flow equation. The solution obtained via Frobenius method is valid in the vicinity of the borehole. This solution is in perfect agreement with the data observed from the pumping test performed by the institute for groundwater study on one of their boreholes settled on the test site of the University of the Free State. The test consisted of the pumping of the borehole at the constant discharge rate Q and monitoring the piezometric head for 350 minutes. Numerical solutions obtained via Adomian method are compared with the Barker generalized radial flow model for which a fractal dimension for the flow is assumed. Proposition for uncertainties in groundwater studies was given.

  1. Laboratory studies of groundwater degassing in replicas of natural fractured rock for linear flow geometry

    International Nuclear Information System (INIS)

    Geller, J.T.

    1998-02-01

    Laboratory experiments to simulate two-phase (gas and water) flow in fractured rock evolving from groundwater degassing were conducted in transparent replicas of natural rock fractures. These experiments extend the work by Geller et al. (1995) and Jarsjo and Geller (1996) that tests the hypothesis that groundwater degassing caused observed flow reductions in the Stripa Simulated Drift Experiment (SDE). Understanding degassing effects over a range of gas contents is needed due to the uncertainty in the gas contents of the water at the SDE. The main objectives of this study were to: (1) measure the effect of groundwater degassing on liquid flow rates for lower gas contents than the values used in Geller for linear flow geometry in the same fracture replicas of Geller; (2) provide a data set to develop a predictive model of two-phase flow in fractures for conditions of groundwater degassing; and (3) improve the certainty of experimental gas contents (this effort included modifications to the experimental system used by Geller et al. and separate gas-water equilibration tests). The Stripa site is being considered for a high-level radioactive waste repository

  2. Groundwater flow system stability in shield settings a multi-disciplinary approach

    International Nuclear Information System (INIS)

    Jensen, M.R.; Goodwin, B.W.

    2004-01-01

    Within the Deep Geologic Repository Technology Program (DGRTP) several Geoscience activities are focused on advancing the understanding of groundwater flow system evolution and geochemical stability in a Shield setting as affected by long-term climate change. A key aspect is developing confidence in predictions of groundwater flow patterns and residence times as they relate to the safety of a Deep Geologic Repository for used nuclear fuel waste. A specific focus in this regard has been placed on constraining redox stability and groundwater flow system dynamics during the Pleistocene. Attempts are being made to achieve this through a coordinated multi-disciplinary approach intent on; i) demonstrating coincidence between independent geo-scientific data; ii) improving the traceability of geo-scientific data and its interpretation within a conceptual descriptive model(s); iii) improving upon methods to assess and demonstrate robustness in flow domain prediction(s) given inherent flow domain uncertainties (i.e. spatial chemical/physical property distributions; boundary conditions) in time and space; and iv) improving awareness amongst geo-scientists as to the utility various geo-scientific data in supporting a repository safety case. Coordinated by the DGRTP, elements of this program include the development of a climate driven Laurentide ice-sheet model to constrain the understanding of time rate of change in boundary conditions most affecting the groundwater flow domain and its evolution. Further work has involved supporting WRA Paleo-hydrogeologic studies in which constrained thermodynamic analyses coupled with field studies to characterize the paragenesis of fracture infill mineralogy are providing evidence to premise understandings of possible depth of penetration by oxygenated glacial recharge. In parallel. numerical simulations have been undertaken to illustrate aspect of groundwater flow system stability and evolution in a Shield setting. Such simulations

  3. Stream flow - its estimation, uncertainty and interaction with groundwater and floodplains

    DEFF Research Database (Denmark)

    Poulsen, Jane Bang

    , floodplain hydraulics and sedimentation patterns has been investigated along a restored channel section of Odense stream, Denmark. Collected samples of deposited sediment, organic matter and phosphorus on the floodplain were compared with results from a 2D dynamic flow model. Three stage dependent flow...... regimes were predicted by the flow model with shifting primary overbank flow and zones of flow confluence. These dynamic flow patterns were found to correlate with the spatial deposition of total phosphorus (11.4 g m-2), organic matter (0.65 kg m-2) and sediment (4.72 kg m-2), and zones of major total...... sediment deposition coincided with the flow confluence zones. The revealed complex spatially and temporally changing floodplain flow pattern was found to play a decisive role for the deposition processes. The interaction between stream flow and groundwater from catchment to point scale has been...

  4. Budgets and chemical characterization of groundwater for the Diamond Valley flow system, central Nevada, 2011–12

    Science.gov (United States)

    Berger, David L.; Mayers, C. Justin; Garcia, C. Amanda; Buto, Susan G.; Huntington, Jena M.

    2016-07-29

    The Diamond Valley flow system consists of six hydraulically connected hydrographic areas in central Nevada. The general down-gradient order of the areas are southern and northern Monitor Valleys, Antelope Valley, Kobeh Valley, Stevens Basin, and Diamond Valley. Groundwater flow in the Diamond Valley flow system terminates at a large playa in the northern part of Diamond Valley. Concerns relating to continued water-resources development of the flow system resulted in a phased hydrologic investigation that began in 2005 by the U.S. Geological Survey in cooperation with Eureka County. This report presents the culmination of the phased investigation to increase understanding of the groundwater resources of the basin-fill aquifers in the Diamond Valley flow system through evaluations of groundwater chemistry and budgets. Groundwater chemistry was characterized using major ions and stable isotopes from groundwater and precipitation samples. Groundwater budgets accounted for all inflows, outflows, and changes in storage, and were developed for pre-development (pre-1950) and recent (average annual 2011–12) conditions. Major budget components include groundwater discharge by evapotranspiration and groundwater withdrawals; groundwater recharge by precipitation, and interbasin flow; and storage change.

  5. Study on groundwater flow system in a sedimentary rock area (part 2). Case study for the Yoro river basin, Chiba prefecture

    International Nuclear Information System (INIS)

    Sakai, Ryutaro; Munakata, Masahiro; Kimura, Hideo

    2008-01-01

    In the safety assessment for a geological disposal of long-lived radioactive waste such as high-level radioactive waste and TRU waste etc, it is important to estimate radionuclide migration to human environment through groundwater flow system. Japan Atomic Energy Agency (JAEA) has investigated a sedimentary rock area in the Yoro river basin, in Chiba Prefecture. The hydrological and geo-chemical approach is necessary for revealing the conditions of the groundwater flow system. For the purpose of establishing a methodology for these approach, investigations of flow rates and chemical compositions, isotopic ratios of hydrogen and oxygen for water samples collected from wells, rivers and springs were carried out in the 3 feeder streams as Urajiro, Imohara and Umegase river locating at the central part of the Yoro river basin. As a result, flow rates and chemical composition data suggested that considerable amount of ground water cultivated at the high permeable sand dominant layer (Daifuku Mt.) preferentially flows toward its strike direction discharging at the downstream region of Imohara and the Umegase river. The rest of the ground water was inferred to form different flowpath toward the dipping direction of bedrock more than 100m at depth and to upwell to the Urajiro River through the low permeable mud layer. Chemical composition and isotopic data indicated that most of the ground water in meteoric water origin is NaCa-HCO 3 type as represented by surface water or the evolved Ca-HCO 3 type water but the part of the upwelling water at the downstream region of Urajiro river is Na-HCO 3 type water with long residence time. This study shows that both hydrological and geo-chemical approach could be available to evaluate the relationships between shallow water and deep-seated groundwater, so it is necessary to apply this approach to regional ground water flow systems. (author)

  6. Estimation of the sources and flow system of groundwater in Fuji-Gotenba area by stable isotopic analysis and groundwater flow simulation

    International Nuclear Information System (INIS)

    Tomiyama, Shingo; Miyaike, Shusaku; Ii, Hiroyuki; Hattori, Ryota; Ito, Yuji

    2009-01-01

    Understanding the source and chemical character of the groundwater provides an important strategy for the quality management of mineral water and food materials. In order to identify a source and the flow paths of groundwater used for mineral water, the water quality and stable isotopes of hydrogen and oxygen of well water in Gotenba city were studied. The electrical conductivity and chemical character of sampled water are similar to those of well water and spring water discharged elsewhere around Mt. Fuji. The hydrogen and oxygen isotopic ratios of water samples indicate their origin to be solely meteoric and the oxygen isotopic ratios suggest that the groundwater mainly originated from the mountain-side of Mt. Fuji at altitudes of from 1500 m to 2300 m. A subsequent simulation of groundwater showed that the distribution of the total head and the Darcy velocity are down streamlines from mountain-sides toward the study area in Gotenba city. The altitudes of discharge obtained by the simulation are above 2000 m, and these correspond well with altitudes estimated from δ 18 O values of the samples. (author)

  7. Groundwater flow systems in the great Aletsch glacier region (Valais, Switzerland)

    Science.gov (United States)

    Alpiger, Andrea; Loew, Simon

    2014-05-01

    Groundwater flow systems in Alpine areas are often complex and challenging to investigate due to special topographic and climatic conditions governing groundwater recharge and bedrock flow. Studies seeking to characterize high-alpine groundwater systems remain rare, but are of high interest, e.g. for water supply, hydropower systems, traffic tunnels or rock slope deformation and landslide hazards. The goal of this study is to better understand the current and past groundwater flow systems of the UNESCO World Heritage mountain ridge separating the great Aletsch glacier and the Rhone valley, considering climatic and glacier fluctuations during the Lateglacial and Holocene periods. This ridge is crossed by a hydropower bypass drift (Riederhornstollen) and is composed of fractured crystalline rocks overlain by various types of landslides and glacial deposits. Surface hydrology observations (fracture properties, groundwater seepage, spring lines and physico-chemical parameters) and hydropower drift inflow measurements contributed to the characterization of bedrock hydraulic conductivities and preferential groundwater pathways. Basic conceptual hydrogeological models were tested with observed drift inflows and the occurrence of springs using free-surface, variably saturated, vertical 2D groundwater flow models (using the code SEEP/W from GeoStudio 2007). Already simple two-layer models, representing profile sections orthogonal to the mountain ridge, provided useful results. Simulations show that differences in the occurrence of springs on each side of the mountain ridge are likely caused by the occurrence of glacial till (generating perched groundwater), the deep-seated sagging landslide mass, faults and asymmetric ridge topography, which together force the main groundwater flow direction to be oriented towards the Rhone valley, even from beyond the mountain ridge. Surprisingly, the most important springs (those with high discharge rates) are located at high elevations

  8. Characterisation of discharge areas of radionuclides originating from nuclear waste repositories

    International Nuclear Information System (INIS)

    Marklund, L.; Woerman, A.

    2008-01-01

    In this study, we investigate if there are certain landscape elements that will generally act as discharge areas for radio-nuclides leaking from a subsurface deposit of nuclear waste. We also characterize the typical properties that distinguish these areas from others. Understanding the processes controlling the clustering of discharge to certain areas is an additional topic of study. Landscape topography is the most important driving force for groundwater flow. Because groundwater is the main transporting agent for migrating radio-nuclides, the topography will determine the flow paths of leaking radionuclides. How topography and heterogeneities in the subsurface affect the discharge distribution of the radionuclides is the main scope of this study. An analytical and a numerical model are used. Conclusions are: Our results suggest that the varieties of landscape elements which have potential for receiving significant amounts of radio-nuclides are limited. To save recourses, the surficial radiological assessments should therefore be focused in these areas. Furthermore, the discharge areas of groundwater from repository depth have defining characteristics that distinguish them from discharge areas of shallower groundwater flow cells. Due to the similarities within deep groundwater discharge areas, one can make site-specific analyses of those areas, which have a broad applicability for migration of radio-nuclides originating from a nuclear waste repository (author)(tk)

  9. Modeling groundwater flow to elliptical lakes and through multi-aquifer elliptical inhomogeneities

    Science.gov (United States)

    Bakker, Mark

    2004-05-01

    Two new analytic element solutions are presented for steady flow problems with elliptical boundaries. The first solution concerns groundwater flow to shallow elliptical lakes with leaky lake beds in a single-aquifer. The second solution concerns groundwater flow through elliptical cylinder inhomogeneities in a multi-aquifer system. Both the transmissivity of each aquifer and the resistance of each leaky layer may differ between the inside and the outside of an inhomogeneity. The elliptical inhomogeneity may be bounded on top by a shallow elliptical lake with a leaky lake bed. Analytic element solutions are obtained for both problems through separation of variables of the Laplace and modified-Helmholtz differential equations in elliptical coordinates. The resulting equations for the discharge potential consist of infinite sums of products of exponentials, trigonometric functions, and modified-Mathieu functions. The series are truncated but still fulfill the differential equation exactly; boundary conditions are met approximately, but up to machine accuracy provided enough terms are used. The head and flow may be computed analytically at any point in the aquifer. Examples are given of uniform flow through an elliptical lake, a well pumping near two elliptical lakes, and uniform flow through three elliptical inhomogeneities in a multi-aquifer system. Mathieu functions may be applied in a similar fashion to solve other groundwater flow problems in semi-confined aquifers and leaky aquifer systems with elliptical internal or external boundaries.

  10. Fractional governing equations of transient groundwater flow in confined aquifers with multi-fractional dimensions in fractional time

    Directory of Open Access Journals (Sweden)

    M. L. Kavvas

    2017-10-01

    Full Text Available Using fractional calculus, a dimensionally consistent governing equation of transient, saturated groundwater flow in fractional time in a multi-fractional confined aquifer is developed. First, a dimensionally consistent continuity equation for transient saturated groundwater flow in fractional time and in a multi-fractional, multidimensional confined aquifer is developed. For the equation of water flux within a multi-fractional multidimensional confined aquifer, a dimensionally consistent equation is also developed. The governing equation of transient saturated groundwater flow in a multi-fractional, multidimensional confined aquifer in fractional time is then obtained by combining the fractional continuity and water flux equations. To illustrate the capability of the proposed governing equation of groundwater flow in a confined aquifer, a numerical application of the fractional governing equation to a confined aquifer groundwater flow problem was also performed.

  11. Modelling of seasonal dynamics of Wetland-Groundwater flow interaction in the Canadian Prairies

    Science.gov (United States)

    Ali, Melkamu; Nussbaumer, Raphaël; Ireson, Andrew; Keim, Dawn

    2015-04-01

    Wetland-shallow groundwater interaction is studied at the St. Denis National Wildlife Area in Saskatchewan, Canada, located within the northern glaciated prairies of North America. Ponds in the Canadian Prairies are intermittently connected by fill-spill processes in the spring and growing season of some wetter years. The contribution of the ponds and wetlands to groundwater is still a significant research challenge. The objective of this study is to evaluate model's ability to reproduce observed effects of groundwater-wetland interactions including seasonal pattern of shallow groundwater table, intended flow direction and to quantify the depression induced infiltration from the wetland to the surrounding uplands. The integrated surface-wetland-shallow groundwater processes and the changes in land-energy and water balances caused by the flow interaction are simulated using ParFlow-CLM at a small watershed of 1km2 containing both permanent and seasonal wetland complexes. We compare simulated water table depth with piezometers reading monitored by level loggers at the watershed. We also present the strengths and limitations of the model in reproducing observed behaviour of the groundwater table response to the spring snowmelt and summer rainfall. Simulations indicate that the shallow water table at the uphill recovers quickly after major rainfall events in early summer that generates lateral flow to the pond. In late summer, the wetland supplies water to the surrounding upland when the evapotranspiration is higher than the precipitation in which more water from the root zone is up taken by plants. Results also show that Parflow-CLM is able to reasonably simulate the water table patterns response to summer rainfall, while it is insufficient to reproduce the spring snowmelt infiltration which is the most dominant hydrological process in the Prairies.

  12. Groundwater flow and its effect on salt dissolution in Gypsum Canyon watershed, Paradox Basin, southeast Utah, USA

    Science.gov (United States)

    Reitman, Nadine G.; Ge, Shemin; Mueller, Karl

    2014-09-01

    Groundwater flow is an important control on subsurface evaporite (salt) dissolution. Salt dissolution can drive faulting and associated subsidence on the land surface and increase salinity in groundwater. This study aims to understand the groundwater flow system of Gypsum Canyon watershed in the Paradox Basin, Utah, USA, and whether or not groundwater-driven dissolution affects surface deformation. The work characterizes the groundwater flow and solute transport systems of the watershed using a three-dimensional (3D) finite element flow and transport model, SUTRA. Spring samples were analyzed for stable isotopes of water and total dissolved solids. Spring water and hydraulic conductivity data provide constraints for model parameters. Model results indicate that regional groundwater flow is to the northwest towards the Colorado River, and shallow flow systems are influenced by topography. The low permeability obtained from laboratory tests is inconsistent with field observed discharges, supporting the notion that fracture permeability plays a significant role in controlling groundwater flow. Model output implies that groundwater-driven dissolution is small on average, and cannot account for volume changes in the evaporite deposits that could cause surface deformation, but it is speculated that dissolution may be highly localized and/or weaken evaporite deposits, and could lead to surface deformation over time.

  13. Region-scale groundwater flow modelling of generic high level waste disposal sites

    International Nuclear Information System (INIS)

    Metcalfe, D.

    1996-02-01

    Regional-scale groundwater flow modelling analyses are performed on generic high level waste (HLW) disposal sites to assess the extent to which a large crystalline rock mass such as a pluton or batholith can be expected to contain and isolate HLW in terms of hydraulic considerations, for a variety of geologic and hydrogeologic conditions. The two-dimensional cross-sectional conceptual models of generic HLW disposal sites are evaluated using SWIFT III, which is a finite-difference flow and transport code. All steps leading to the final results and conclusions are incorporated in this report. The available data and information on geological and hydrogeologic conditions in plutons and batholiths are summarized. The generic conceptual models developed from this information are defined in terms of the finite difference grid, the geologic and hydrogeologic properties and the hydrologic boundary conditions used. The modelled results are described with contour maps showing the modelled head fields, groundwater flow paths and travel times and groundwater flux rates within the modelled systems. The results of the modelling analyses are used to develop general conclusions on the scales and patterns of groundwater flow in granitic plutons and batholiths. The conclusions focus on geologic and hydrogeologic characteristics that can result in favourable conditions, in terms of hydraulic considerations, for a HLW repository. (author) 43 refs., 9 tabs., 40 figs

  14. Structural Controls on Groundwater Flow in Basement Terrains: Geophysical, Remote Sensing, and Field Investigations in Sinai

    KAUST Repository

    Mohamed, Lamees; Sultan, Mohamed; Ahmed, Mohamed; Zaki, Abotalib; Sauck, William; Soliman, Farouk; Yan, Eugene; Elkadiri, Racha; Abouelmagd, Abdou

    2015-01-01

    of the structural controls on the groundwater flow. The increase in satellite-based radar backscattering values following a large precipitation event (34 mm on 17–18 January 2010) was used to identify water-bearing features, here interpreted as preferred pathways

  15. Numerical modeling analysis of VOC removal processes in different aerobic vertical flow systems for groundwater remediation

    NARCIS (Netherlands)

    De Biase, C.; Carminati, A.; Oswald, S.E.; Thullner, M.

    2013-01-01

    Vertical flow systems filled with porous medium have been shown to efficiently remove volatile organic contaminants (VOCs) from contaminated groundwater. To apply this semi-natural remediation strategy it is however necessary to distinguish between removal due to biodegradation and due to volatile

  16. Solute transport by groundwater flow to wetland ecosystems : the environmental impact of human activities

    NARCIS (Netherlands)

    Schot, P.P.

    1991-01-01

    This thesis deals with solute transport by groundwater flow and the way in which solute transport is affected by human activities. This in relation to wetland ecosystems. Wetlands in the eastern part of the Vecht river plain in The Netherlands are historically renown for their great variety of

  17. 3-D numerical modelling of groundwater flow for scenario-based ...

    African Journals Online (AJOL)

    The data related to piezometric water levels, canal gauges, well logs, meteorological and lithological information were collected from Punjab Irrigation Department (PID), Water and Power Development Authority (WAPDA). Groundwater flow models for both steady and transient conditions were set-up using FEFLOW-3D.

  18. Iron oxidation kinetics and phosphate immobilization along the flow-path from groundwater into surface water

    NARCIS (Netherlands)

    Van Der Grift, B.; Rozemeijer, J. C.; Griffioen, J.; Van Der Velde, Y.

    2014-01-01

    The retention of phosphorus in surface waters through co-precipitation of phosphate with Fe-oxyhydroxides during exfiltration of anaerobic Fe(II) rich groundwater is not well understood. We developed an experimental field set-up to study Fe(II) oxidation and P immobilization along the flow-path from

  19. Iron oxidation kinetics and phosphate immobilization along the flow-path from groundwater into surface water.

    NARCIS (Netherlands)

    Grift, van der B.; Rozemeijer, J.C.; Griffioen, J.; Velde, van der Y.

    2014-01-01

    The retention of phosphorus in surface waters though co-precipitation of phosphate with Fe-oxyhydroxides during exfiltration of anaerobic Fe(II) rich groundwater is not well understood. We developed an experimental field set-up to study Fe(II) oxidation and 5 P immobilization along the flow-path

  20. Iron oxidation kinetics and phosphate immobilization along the flow-path from groundwater into surface water

    NARCIS (Netherlands)

    van der Grift, B.; Rozemeijer, J. C.; Griffioen, J.; van der Velde, Y.

    2014-01-01

    The retention of phosphorus in surface waters though co-precipitation of phosphate with Fe-oxyhydroxides during exfiltration of anaerobic Fe(II) rich groundwater is not well understood. We developed an experimental field set-up to study Fe(II) oxidation and P immobilization along the flow-path from

  1. Stepwise hydrogeological modeling and groundwater flow analysis on site scale (step 2)

    International Nuclear Information System (INIS)

    Onoe, Hironori; Saegusa, Hiromitsu; Endo, Yoshinobu

    2005-02-01

    One of the main goals of the Mizunami Underground Research Laboratory Project is to establish comprehensive techniques for investigation, analysis, and assessment of the deep geological environment. To achieve this goal, a variety of investigations are being conducted using an iterative approach. In this study, hydrogeological modeling and groundwater flow analyses have been carried out using the data from surface-based investigations at Step 2, in order to synthesize the investigation results, to evaluate the uncertainty of the hydrogeological model, and to specify items for further investigation. The results of this study are summarized as follows: 1) The understanding of groundwater flow is enhanced, and the hydrogeological model has renewed; 2) The importance of faults as major groundwater flow pathways has been demonstrated; 3) The importance of iterative approach as progress of investigations has been demonstrated; 4) Geological and hydraulic characteristics of faults with orientation of NNW, NW and NE were shown to be especially significant; 5) the hydraulic properties of the Lower Sparsely Fractured Domain (LSFD) significantly influence the groundwater flow. The main items specified for further investigations are summarized as follows: 1) Geological and hydraulic characteristics of NNW, NW and NE trending faults; 2) Hydraulic properties of the LSFD; 3) More accuracy upper and lateral boundary conditions of the site scale model. (author)

  2. Comparison of groundwater flow in Southern California coastal aquifers

    Science.gov (United States)

    Hanson, Randall T.; Izbicki, John A.; Reichard, Eric G.; Edwards, Brian D.; Land, Michael; Martin, Peter

    2009-01-01

    Development of the coastal aquifer systems of Southern California has resulted in overdraft, changes in streamflow, seawater intrusion, land subsidence, increased vertical flow between aquifers, and a redirection of regional flow toward pumping centers. These water-management challenges can be more effectively addressed by incorporating new understanding of the geologic, hydrologic, and geochemical setting of these aquifers.

  3. Radionuclide measurement of urinary flow rates and residual urine in the evaluation of bladder outflow obstruction

    International Nuclear Information System (INIS)

    Groshar, D.; Embon, O.M.; Sazbon, A.; Koritny, E.; Frankel, A.

    1986-01-01

    A radionuclide method was developed to evaluate bladder outflow obstruction. Forty-seven patients with prostatic hypertrophy and 29 controls were studied. Urinary mean (MRF) and peak (PFR) flow rates were determined from the time-activity curves of bladder emptying. Residual urine (RU) was calculated by the volume voided and the bladder ejection fraction. A corrected PFR was calculated [CPFR = PFR/(vol. voided + RU)/sup 1/2/]. There was significant difference between patients and controls (MFR = 4 +- 2 vs. 9 +- 4 ml/sec, P <.001; PFR = 10 +- 6 vs. 20 +- 7, P <.001; CPFR = 0.57 +- 0.21 vs. 1.22 +- 0.32, P <.0001). RU was 13 +- 13 ml in controls and 155 +- 285 ml in patients (P <.01). CPFR was less than 0.89 in 94% of patients and 10% of controls, PFR was less than 14 ml/sec in 79% of patients and 17% of controls, and MFR was less than 7 ml/sec in 91% of patients and 21% of controls. The method enables good separation between patients and controls in a single examination that measures both flow and volume

  4. Hydrogeology, groundwater flow, and groundwater quality of an abandoned underground coal-mine aquifer, Elkhorn Area, West Virginia

    Science.gov (United States)

    Kozar, Mark D.; McCoy, Kurt J.; Britton, James Q.; Blake, B.M.

    2017-01-01

    The Pocahontas No. 3 coal seam in southern West Virginia has been extensively mined by underground methods since the 1880’s. An extensive network of abandoned mine entries in the Pocahontas No. 3 has since filled with good-quality water, which is pumped from wells or springs discharging from mine portals (adits), and used as a source of water for public supplies. This report presents results of a three-year investigation of the geology, hydrology, geochemistry, and groundwater flow processes within abandoned underground coal mines used as a source of water for public supply in the Elkhorn area, McDowell County, West Virginia. This study focused on large (> 500 gallon per minute) discharges from the abandoned mines used as public supplies near Elkhorn, West Virginia. Median recharge calculated from base-flow recession of streamflow at Johns Knob Branch and 12 other streamflow gaging stations in McDowell County was 9.1 inches per year. Using drainage area versus mean streamflow relationships from mined and unmined watersheds in McDowell County, the subsurface area along dip of the Pocahontas No. 3 coal-mine aquifer contributing flow to the Turkey Gap mine discharge was determined to be 7.62 square miles (mi2), almost 10 times larger than the 0.81 mi2 surface watershed. Results of this investigation indicate that groundwater flows down dip beneath surface drainage divides from areas up to six miles east in the adjacent Bluestone River watershed. A conceptual model was developed that consisted of a stacked sequence of perched aquifers, controlled by stress-relief and subsidence fractures, overlying a highly permeable abandoned underground coal-mine aquifer, capable of substantial interbasin transfer of water. Groundwater-flow directions are controlled by the dip of the Pocahontas No. 3 coal seam, the geometry of abandoned mine workings, and location of unmined barriers within that seam, rather than surface topography. Seven boreholes were drilled to intersect

  5. Groundwater flow model for the Little Plover River basin in Wisconsin’s Central Sands

    Science.gov (United States)

    Ken Bradbury,; Fienen, Michael N.; Kniffin, Maribeth; Jacob Krause,; Westenbroek, Stephen M.; Leaf, Andrew T.; Barlow, Paul M.

    2017-01-01

    The Little Plover River is a groundwater-fed stream in the sand plains region of central Wisconsin. In this region, sandy sediment deposited during or soon after the last glaciation forms an important unconfined sand and gravel aquifer. This aquifer supplies water for numerous high-capacity irrigation, municipal, and industrial wells that support a thriving agricultural industry. In recent years the addition of many new wells, combined with observed diminished flows in the Little Plover and other nearby rivers, has raised concerns about the impacts of the wells on groundwater levels and on water levels and flows in nearby lakes, streams, and wetlands. Diverse stakeholder groups, including well operators, Growers, environmentalists, local land owners, and regulatory and government officials have sought a better understanding of the local groundwater-surface water system and have a shared desire to balance the water needs of the he liagricultural, industrial, and urban users with the maintenance and protection of groundwater-dependent natural resources. To help address these issues, the Wisconsin Department of Natural Resources requested that the Wisconsin Geological and Natural History Survey and U.S. Geological Survey cooperatively develop a groundwater flow model that could be used to demonstrate the relationships among groundwater, surface water, and well withdrawals and also be a tool for testing and evaluating alternative water management strategies for the central sands region. Because of an abundance of previous studies, data availability, local interest, and existing regulatory constraints the model focuses on the Little Plover River watershed, but the modeling methodology developed during this study can apply to much of the larger central sands of Wisconsin. The Little Plover River groundwater flow model simulates three-dimensional groundwater movement in and around the Little Plover River basin under steady-state and transient conditions. This model

  6. Hydrogeology and simulation of ground-water flow near the Lantana Landfill, Palm Beach County, Florida

    Science.gov (United States)

    Russell, G.M.; Wexler, E.J.

    1993-01-01

    The Lantana landfill in Palm Beach County has a surface that is 40 to 50 feet above original ground level and consists of about 250 acres of compacted garbage and trash. Parts of the landfill are below the water table. Surface-resistivity measurements and water-quality analyses indicate that leachate-enriched ground water along the eastern perimeter of the landfill has moved about 500 feet eastward toward an adjacent lake. Concentrations of chloride and nutrients within the leachate-enriched ground water were greater than background concentrations. The surficial aquifer system in the area of the landfill consists primarily of sand of moderate permeability, from land surface to a depth of about 68 feet deep, and consists of sand interbedded with sandstone and limestone of high permeability from a depth of about 68 feet to a depth of 200 feet. The potentiometric surface in the landfill is higher than that in adjacent areas to the east, indicating ground-water movement from the landfill toward a lake to the east. Steady-state simulation of ground-water flow was made using a telescoping-grid technique where a model covering a large area is used to determine boundaries and fluxes for a finer scale model. A regional flow model encompassing a 500-square mile area in southeastern Palm Beach County was used to calculate ground-water fluxes in a 126.5-square mile subregional area. Boundary fluxes calculated by the subregional model were then used to calculate boundary fluxes for a local model of the 3.75-square mile area representing the Lantana landfill site and vicinity. Input data required for simulating ground-water flow in the study area were obtained from the regional flow models, thus, effectively coupling the models. Additional simulations were made using the local flow model to predict effects of possible remedial actions on the movement of solutes in the ground-water system. Possible remedial actions simulated included capping the landfill with an impermeable layer

  7. Ground-water monitoring and modeling at the Hanford Site

    International Nuclear Information System (INIS)

    Mitchell, P.J.; Freshley, M.D.

    1987-01-01

    The ground-water monitoring program at the Hanford Site in southeastern Washington State is continually evolving in response to changing operations at the site, changes in the ground-water flow system, movement of the constituents in the aquifers, and regulatory requirements. Sampling and analysis of ground water, along with ground-water flow and solute transport modeling are used to evaluate the movement and resulting distributions of radionuclides and hazardous chemical constituents in the unconfined aquifer. Evaluation of monitoring results, modeling, and information on waste management practices are being combined to continually improve the network of ground-water monitoring wells at the site

  8. Ground-water monitoring and modeling at the Hanford Site

    International Nuclear Information System (INIS)

    Mitchell, P.J.; Freshley, M.D.

    1987-01-01

    The ground-water monitoring program at the Hanford Site in southeastern Washington State is continually evolving in response to changing operations at the site, changes in the ground-water flow system, movement of the constituents in the aquifers, and regulatory requirements. Sampling and analysis of ground water, along with ground-water flow and solute transport modeling are used ito evaluate the movement and resulting distributions of radionuclides and hazardous chemical constituents in the unconfined aquifer. Evaluation of monitoring results, modeling, and information on waste management practices are being combined to continually improve the network of ground-water monitoring wells at the site

  9. Closing the irrigation deficit in Cambodia: Implications for transboundary impacts on groundwater and Mekong River flow

    Science.gov (United States)

    Erban, Laura E.; Gorelick, Steven M.

    2016-04-01

    Rice production in Cambodia, essential to food security and exports, is largely limited to the wet season. The vast majority (96%) of land planted with rice during the wet season remains fallow during the dry season. This is in large part due to lack of irrigation capacity, increases in which would entail significant consequences for Cambodia and Vietnam, located downstream on the Mekong River. Here we quantify the extent of the dry season ;deficit; area in the Cambodian Mekong River catchment, using a recent agricultural survey and our analysis of MODIS satellite data. Irrigation of this land for rice production would require a volume of water up to 31% of dry season Mekong River flow to Vietnam. However, the two countries share an aquifer system in the Mekong Delta, where irrigation demand is increasingly met by groundwater. We estimate expansion rates of groundwater-irrigated land to be >10% per year in the Cambodian Delta using LANDSAT satellite data and simulate the effects of future expansion on groundwater levels over a 25-year period. If groundwater irrigation continues to expand at current rates, the water table will drop below the lift limit of suction pump wells, used for domestic supply by >1.5 million people, throughout much of the area within 15 years. Extensive groundwater irrigation jeopardizes access for shallow domestic water supply wells, raises the costs of pumping for all groundwater users, and may exacerbate arsenic contamination and land subsidence that are already widespread hazards in the region.

  10. Exposure Time Distributions reveal Denitrification Rates along Groundwater Flow Path of an Agricultural Unconfined Aquifer

    Science.gov (United States)

    Kolbe, T.; Abbott, B. W.; Thomas, Z.; Labasque, T.; Aquilina, L.; Laverman, A.; Babey, T.; Marçais, J.; Fleckenstein, J. H.; Peiffer, S.; De Dreuzy, J. R.; Pinay, G.

    2016-12-01

    Groundwater contamination by nitrate is nearly ubiquitous in agricultural regions. Nitrate is highly mobile in groundwater and though it can be denitrified in the aquifer (reduced to inert N2 gas), this process requires the simultaneous occurrence of anoxia, an electron donor (e.g. organic carbon, pyrite), nitrate, and microorganisms capable of denitrification. In addition to this the ratio of the time groundwater spent in a denitrifying environment (exposure time) to the characteristic denitrification reaction time plays an important role, because denitrification can only occur if the exposure time is longer than the characteristic reaction time. Despite a long history of field studies and numerical models, it remains exceedingly difficult to measure or model exposure times in the subsurface at the catchment scale. To approach this problem, we developed a unified modelling approach combining measured environmental proxies with an exposure time based reactive transport model. We measured groundwater age, nitrogen and sulfur isotopes, and water chemistry from agricultural wells in an unconfined aquifer in Brittany, France, to quantify changes in nitrate concentration due to dilution and denitrification. Field data showed large differences in nitrate concentrations among wells, associated with differences in the exposure time distributions. By constraining a catchment-scale characteristic reaction time for denitrification with water chemistry proxies and exposure times, we were able to assess rates of denitrification along groundwater flow paths. This unified modeling approach is transferable to other catchments and could be further used to investigate how catchment structure and flow dynamics interact with biogeochemical processes such as denitrification.

  11. Second status report on regional ground-water flow modeling for the Palo Duro Basin, Texas

    International Nuclear Information System (INIS)

    1986-07-01

    Regional ground-water flow within the principal geohydrologic units of the Palo Duro Basin is evaluated by developing a conceptual model of the flow regime and testing the model using a three-dimensional, finite-difference flow code. Sensitivity analyses (a limited parametric study) are conducted to define the system responses to changes in the conceptual model. Of particular interest are the impacts of salt permeability and potential climatic changes on the system response. The conceptual model is described in terms of its areal and vertical discretization, aquifer properties, fluid properties and hydrologic boundary conditions. The simulated ground-water flow fields are described with potentiometric surfaces, tables summarizing the areal and vertical volumetric flows through the principal units, and Darcy velocities within specified finite-difference blocks. The reported work is the second stage of an ongoing evaluation of the Palo Duro Basin as a potential repository for high-level radioactive wastes. The results and conclusions should thus be considered preliminary and subject to modification with the collection of additional data. However, the report does provide a useful basis for describing the sensitivity of the present conceptualization of ground-water flow to particular parameters and, to a lesser extent, the uncertainties in the present conceptualization. 28 refs., 44 figs., 13 tabs

  12. Hydrogeology, simulated ground-water flow, and ground-water quality, Wright-Patterson Air Force Base, Ohio

    Science.gov (United States)

    Dumouchelle, D.H.; Schalk, C.W.; Rowe, G.L.; De Roche, J.T.

    1993-01-01

    Ground water is the primary source of water in the Wright-Patterson Air Force Base area. The aquifer consists of glacial sands and gravels that fill a buried bedrock-valley system. Consolidated rocks in the area consist of poorly permeable Ordovician shale of the Richmondian stage, in the upland areas, the Brassfield Limestone of Silurian age. The valleys are filled with glacial sediments of Wisconsinan age consisting of clay-rich tills and coarse-grained outwash deposits. Estimates of hydraulic conductivity of the shales based on results of displacement/recovery tests range from 0.0016 to 12 feet per day; estimates for the glacial sediments range from less than 1 foot per day to more than 1,000 feet per day. Ground water flow from the uplands towards the valleys and the major rivers in the region, the Great Miami and the Mad Rivers. Hydraulic-head data indicate that ground water flows between the bedrock and unconsolidated deposits. Data from a gain/loss study of the Mad River System and hydrographs from nearby wells reveal that the reach of the river next to Wright-Patterson Air Force Base is a ground-water discharge area. A steady-state, three-dimensional ground-water-flow model was developed to simulate ground-water flow in the region. The model contains three layers and encompasses about 100 square miles centered on Wright-Patterson Air Force Base. Ground water enters the modeled area primarily by river leakage and underflow at the model boundary. Ground water exits the modeled area primarily by flow through the valleys at the model boundaries and through production wells. A model sensitivity analysis involving systematic changes in values of hydrologic parameters in the model indicates that the model is most sensitive to decreases in riverbed conductance and vertical conductance between the upper two layers. The analysis also indicates that the contribution of water to the buried-valley aquifer from the bedrock that forms the valley walls is about 2 to 4

  13. Ground-water flow near two radioactive-waste-disposal areas at the Western New York Nuclear Service Center, Cattaraugus County, New York; results of flow simulation

    Science.gov (United States)

    Bergeron, M.P.; Bugliosi, E.F.

    1988-01-01

    Two adjacent burial areas were excavated in a clay-rich till at a radioactive waste disposal site near West Valley in Cattaraugus County, N.Y.: (1) which contains mainly low-level radioactive wastes generated onsite by a nuclear fuel reprocessing plant, has been in operation since 1966; and (2) which contains commercial low-level radioactive wastes, was operated during 1963-75. Groundwater below the upper 3 meters of till generally moves downward through a 20- to 30-meter thick sequence of tills underlain by lacustrine and kame-delta deposits of fine sand and silt. Groundwater in the weathered, upper 3 meters of till can move laterally for several meters before either moving downward into the kame-delta deposits or discharging to the land surface. A two-dimensional finite-element model that simulates two vertical sections was used to evaluate hydrologic factors that control groundwater flow in the till. Conditions observed during March 1983 were reproduced accurately in steady-state simulations that used four isotropic units of differing hydraulic conductivity to represent two fractured and weathered till units near land surfaces, an intermediate group of isolated till zones that contain significant amounts of fine sand and silt, and a sequence of till units at depths that have been consolidated by overburden pressure. Recharge rates used in the best-fit simulation ranged from 1.4 cm/yr along smooth, sloping or compacted surfaces to 3.8 cm/yr near swampy areas. Values of hydraulic conductivity and infiltration used in the calibrated best-fit model were nearly identical to values used in a previous model analysis of the nearby commercial-waste burial area. Results of the model simulations of a burial pit assumed to be filled with water indicate that water near the bottom of the burial pit would migrate laterally in the shallow, weathered till for 5 to 6 meters before moving downward into the unweathered till, and water near the top of the pit would move laterally

  14. Does leaching of naturally occurring radionuclides from roadway pavements stabilised with coal fly ash have negative impacts on groundwater quality and human health?

    Science.gov (United States)

    Almahayni, T; Vanhoudt, N

    2018-05-05

    We assessed the potential impact of using coal fly ash to stabilise roadway pavements on groundwater quality and human health. The leaching potential of naturally occurring radionuclides (NORs) typically present in the fly ash was assessed with the HYDRUS-1D code and data representative of a segment of the Wisconsin State Trunk Highway 60 as a case study. Our assessment suggests that the impact would be mainly from the chemical toxicity of uranium (U). In our particular case study, U concentration in the leachate exceeded the maximum contaminant level for this element (MCL = 30 μg L -1 ) in almost all the scenarios. In the groundwater, the MCL was only exceeded under conditions of high leaching and low dilution in the aquifer. The radiological toxicity from the consumption of the contaminated groundwater by a hypothetical adult, however, was at maximum 43% of the individual dose criterion (IDC = 0.1 mSv y -1 ). The results also highlight the need to consider site-specific conditions such as climate and hydrogeology when assessing the environmental impacts of utilising fly ash in roadway construction applications since they could have profound effects on the assessment findings. There is also a pressing need for reliable and representative data to support realistic assessments. Copyright © 2018 Elsevier B.V. All rights reserved.

  15. Regional groundwater flow in the Atikokan Research Area : simulation of 18O and 3H distributions

    International Nuclear Information System (INIS)

    Ophori, D.U.; Chan, Tin.

    1994-09-01

    AECL is investigating a concept for disposing of nuclear fuel waste deep in plutonic rock of the Canadian Shield. As part of this investigation, we have performed a model simulation of regional groundwater flow in the Atikokan Research Area, a fractured plutonic rock environment of the Canadian Shield, and used the distribution of oxygen-18 ( 18 O) and tritium ( 3 H) in groundwater to test the model. At the first stage of model calibration, groundwater flow was simulated using a three-dimensional finite-element code, MOTIF, in conjunction with a conceptual framework model derived from field geological, geophysical and hydrogeological data. Hydraulic parameters (permeability and porosity) were systematically varied until simulated recharge rates to the water table compared favourably with estimated recharge rates based on stream flow analysis. At the second stage, vertical average linear groundwater velocities from the first stage of the calibration process were combined with conceptualized one-dimensional models of the system to generate depth concentration profiles of 18 O and 3 H. Recharge-, midline-and discharge area models of both the fracture zones and the rock mass were employed. The simulated profiles formed 'envelopes' around all field 18 O and 3 H data, indicating that the calibrated velocities used in the model are reasonable. The models demonstrate that the scatter of δ 18 O and 3 H field data from the Atikokan Research Area is consistent with the groundwater flow model predictions and can be explained by the complexity arising from different hydraulic regimes (recharge, midline, discharge) and hydrogeologic environments (fracture zones, rock mass) of the regional flow system. 50 refs., 14 figs., 3 tabs

  16. Stratabound pathways of preferred groundwater flow: An example from the Copper Ridge Dolomite in East Tennessee

    International Nuclear Information System (INIS)

    Lee, R.; Ketelle, D.

    1987-01-01

    The Copper Ridge Dolomite of the Upper Cambrian Knox Group underlies a site at Oak Ridge, Tennessee under consideration by the Department of Energy (DOE) for a below ground waste disposal facility. The Copper Ridge was studied for DOE to understand the influence of lithology on deep groundwater flow. Three facies types are distinguished which comprise laterally continuous, 1 to 4 m thick rock units interpreted to represent upward-shallowing depositional cycles having an apparently significant effect on groundwater flow at depth. Rock core observations indicate one of the recurring facies types is characterized by thin to medium-bedded, fine-grained dolostone with planar cryptalgal laminae and thin shaley partings. Distinctive fracturing in this facies type, that may have resulted from regional structural deformation, it considered to be responsible for weathering at depth and the development of stratabound pathways of preferred groundwater flow. In addition, geophysical data suggest that one occurrence of this weathered facies type coincides with an apparent geochemical interface at depth. Geophysical data also indicate the presence of several fluid invasion horizons, traceable outside the study area, which coincide with the unweathered occurrence of this fine-grained facies type. The subcropping of recurrent zones of preferred groundwater flow at the weathered/unweathered interface may define linear traces of enhanced aquifer recharge paralleling geologic strike. Vertical projection of these zones from the weathered/unweathered rock interface to the ground surface may describe areas of enhanced infiltration. Tests to determine the role of stratigraphic controls on groundwater flow are key components of future investigations on West Chestnut Ridge. 14 refs., 13 figs

  17. Simulation of groundwater flow and pumping scenarios for 1900–2050 near Mount Pleasant, South Carolina

    Science.gov (United States)

    Fine, Jason M.; Petkewich, Matthew D.; Campbell, Bruce G.

    2017-10-31

    Groundwater withdrawals from the Upper Cretaceous-age Middendorf aquifer in South Carolina have created a large, regional cone of depression in the potentiometric surface of the Middendorf aquifer in Charleston and Berkeley Counties, South Carolina. Groundwater-level declines of as much as 249 feet have been observed in wells over the past 125 years and are a result of groundwater use for public water supply, irrigation, and private industry. To address the concerns of users of the Middendorf aquifer, the U.S. Geological Survey, in cooperation with Mount Pleasant Waterworks (MPW), recalibrated an existing groundwater-flow model to incorporate additional groundwater-use and water-level data since 2008. This recalibration process consisted of a technique of parameter estimation that uses regularized inversion and employs “pilot points” for spatial hydraulic property characterization. The groundwater-flow system of the Coastal Plain physiographic province of South Carolina and parts of Georgia and North Carolina was simulated using the U.S. Geological Survey finite-difference computer code MODFLOW-2000.After the model recalibration, the following six predictive water-management scenarios were created to simulate potential changes in groundwater flow and groundwater-level conditions in the Mount Pleasant, South Carolina, area: Scenario 1—maximize MPW reverse-osmosis plant capacity by increasing groundwater withdrawals from the Middendorf aquifer from 3.9 million gallons per day (Mgal/d), which was the amount withdrawn in 2015, to 8.58 Mgal/d; Scenario 2—same as Scenario 1, but with the addition of a 0.5 Mgal/d supply well in the Middendorf aquifer near Moncks Corner, South Carolina; Scenario 3—same as Scenario 1, but with the addition of a 1.5 Mgal/d supply well in the Middendorf aquifer near Moncks Corner, South Carolina; Scenario 4—maximize MPW well capacity by increasing withdrawals from the Middendorf aquifer from 3.9 Mgal/d (in 2015) to 10.16 Mgal

  18. Identifying three-dimensional nested groundwater flow systems in a Tóthian basin

    Science.gov (United States)

    Wang, Xu-Sheng; Wan, Li; Jiang, Xiao-Wei; Li, Hailong; Zhou, Yangxiao; Wang, Junzhi; Ji, Xiaohui

    2017-10-01

    Nested groundwater flow systems have been revealed in Tóth's theory as the structural property of basin-scale groundwater circulation but were only well known with two-dimensional (2D) profile models. The method of searching special streamlines across stagnation points for partitioning flow systems, which has been successfully applied in the 2D models, has never been implemented for three-dimensional (3D) Tóthian basins because of the difficulty in solving the dual stream functions. Alternatively, a new method is developed to investigate 3D nested groundwater flow systems without determination of stagnation points. Connective indices are defined to quantify the connection between individual recharge and discharge zones along streamlines. Groundwater circulation cells (GWCCs) are identified according to the distribution of the connective indices and then grouped into local, intermediate and regional flow systems. This method requires existing solution of the flow velocity vector and is implemented via particle tracking technique. It is applied in a hypothetical 3D Tóthian basin with an analytical solution of the flow field and in a real-world basin with a numerical modeling approach. Different spatial patterns of flow systems compared to 2D profile models are found. The outcrops boundaries of GWCCs on water table may significantly deviate from and are not parallel to the nearby water table divides. Topological network is proposed to represent the linked recharge-discharge zones through closed and open GWCCs. Sensitivity analysis indicates that the development of GWCCs depends on the basin geometry, hydraulic parameters and water table shape.

  19. Evolutionary analysis of groundwater flow: Application of multivariate statistical analysis to hydrochemical data in the Densu Basin, Ghana

    Science.gov (United States)

    Yidana, Sandow Mark; Bawoyobie, Patrick; Sakyi, Patrick; Fynn, Obed Fiifi

    2018-02-01

    An evolutionary trend has been postulated through the analysis of hydrochemical data of a crystalline rock aquifer system in the Densu Basin, Southern Ghana. Hydrochemcial data from 63 groundwater samples, taken from two main groundwater outlets (Boreholes and hand dug wells) were used to postulate an evolutionary theory for the basin. Sequential factor and hierarchical cluster analysis were used to disintegrate the data into three factors and five clusters (spatial associations). These were used to characterize the controls on groundwater hydrochemistry and its evolution in the terrain. The dissolution of soluble salts and cation exchange processes are the dominant processes controlling groundwater hydrochemistry in the terrain. The trend of evolution of this set of processes follows the pattern of groundwater flow predicted by a calibrated transient groundwater model in the area. The data suggest that anthropogenic activities represent the second most important process in the hydrochemistry. Silicate mineral weathering is the third most important set of processes. Groundwater associations resulting from Q-mode hierarchical cluster analysis indicate an evolutionary pattern consistent with the general groundwater flow pattern in the basin. These key findings are at variance with results of previous investigations and indicate that when carefully done, groundwater hydrochemical data can be very useful for conceptualizing groundwater flow in basins.

  20. Hydrogeochemical evidence supporting models for groundwater flow around Sellafield, U.K

    International Nuclear Information System (INIS)

    Metcalfe, R.; Milodowski, A.E.; Noy, D.J.

    1999-01-01

    Recently, United Kingdom Nirex Limited has investigated a site near Sellafield, north-west England to assess its suitability as the potential location for a deep underground repository for the disposal of intermediate- level, and some low-level, solid radioactive waste. Groundwater flow at the site was simulated using a variety of computer codes, based upon conceptual models of the hydrogeological system. Chemical data for groundwaters aided the development of these conceptual models, and also provided a check upon the computer models' validity. Mineralogical information can be accommodated within the conceptual and theoretical framework. The results of the investigation are presented. (author)

  1. Linking stream flow and groundwater to avian habitat in a desert riparian system.

    Science.gov (United States)

    Merritt, David M; Bateman, Heather L

    2012-10-01

    Increasing human populations have resulted in aggressive water development in arid regions. This development typically results in altered stream flow regimes, reduced annual flow volumes, changes in fluvial disturbance regimes, changes in groundwater levels, and subsequent shifts in ecological patterns and processes. Balancing human demands for water with environmental requirements to maintain functioning ecosystems requires quantitative linkages between water in streams and ecosystem attributes. Streams in the Sonoran Desert provide important habitat for vertebrate species, including resident and migratory birds. Habitat structure, food, and nest-building materials, which are concentrated in riparian areas, are provided directly or indirectly by vegetation. We measured riparian vegetation, groundwater and surface water, habitat structure, and bird occurrence along Cherry Creek, a perennial tributary of the Salt River in central Arizona, USA. The purpose of this work was to develop an integrated model of groundwater-vegetation-habitat structure and bird occurrence by: (1) characterizing structural and provisioning attributes of riparian vegetation through developing a bird habitat index (BHI), (2) validating the utility of our BHI through relating it to measured bird community composition, (3) determining the riparian plant species that best explain the variability in BHI, (4) developing predictive models that link important riparian species to fluvial disturbance and groundwater availability along an arid-land stream, and (5) simulating the effects of changes in flow regime and groundwater levels and determining their consequences for riparian bird communities. Riparian forest and shrubland vegetation cover types were correctly classified in 83% of observations as a function of fluvial disturbance and depth to water table. Groundwater decline and decreased magnitude of fluvial disturbance caused significant shifts in riparian cover types from riparian forest to

  2. Isotope and hydrochemical models for evaluation the water loss by evaporation and groundwater flow of dams

    International Nuclear Information System (INIS)

    Santiago, M.F.; Reboucas, A.C.; Frischkorn, H.

    1986-01-01

    Two different approaches are made: an isotope model, based on the observation of the 180/160 ratio of the water, and an hydrochemical model, using the Cl - concentration, are described and applied to determine the evaporation and groundwater flow rates from or to dams. During a period of three years the dams Pereira de Miranda and Caxitore in Pentecostes - Ceara-Brazil (80 Km west of Fortaleza), located in the Precambrian cristalline rock area, were studies. The results show that the models have a good applicability, to estimate the average daily depth of evaporation from free-water surfaces, from nearby porous media or the groundwater inflow or outflow. (author) [pt

  3. Grid refinement in Cartesian coordinates for groundwater flow models using the divergence theorem and Taylor's series.

    Science.gov (United States)

    Mansour, M M; Spink, A E F

    2013-01-01

    Grid refinement is introduced in a numerical groundwater model to increase the accuracy of the solution over local areas without compromising the run time of the model. Numerical methods developed for grid refinement suffered certain drawbacks, for example, deficiencies in the implemented interpolation technique; the non-reciprocity in head calculations or flow calculations; lack of accuracy resulting from high truncation errors, and numerical problems resulting from the construction of elongated meshes. A refinement scheme based on the divergence theorem and Taylor's expansions is presented in this article. This scheme is based on the work of De Marsily (1986) but includes more terms of the Taylor's series to improve the numerical solution. In this scheme, flow reciprocity is maintained and high order of refinement was achievable. The new numerical method is applied to simulate groundwater flows in homogeneous and heterogeneous confined aquifers. It produced results with acceptable degrees of accuracy. This method shows the potential for its application to solving groundwater heads over nested meshes with irregular shapes. © 2012, British Geological Survey © NERC 2012. Ground Water © 2012, National GroundWater Association.

  4. Groundwater flow and potential effects on evaporite dissolution in the Paradox Basin, SE Utah

    Science.gov (United States)

    Reitman, N.; Ge, S.; Mueller, K. J.

    2012-12-01

    A hydrogeologic study was conducted in the portion of the Paradox Basin south of the Needles District of Canyonlands National Park, Utah. Geology of the study area comprises fractured and faulted Paleozoic sandstone, limestone, and shale, which are underlain by evaporite cycles of the Paradox Formation. The evaporite deposits deform and dissolve when they come in contact with groundwater, generating land subsidence, saline groundwater, and salt input to the Colorado River. Active faults in the region slip at a rate of approximately 2 mm/year, likely due to evaporite dissolution. The objective of this study is to better understand groundwater flow and solute transport dynamics and to help determine the rate and timing of subsurface salt dissolution, which is an important control on the salt tectonics in the region. Study methods include hydrologic fieldwork, laboratory tests, and numerical modeling. No groundwater wells exist in the study area. Water samples from springs and seeps were collected throughout the study area. Analysis of total dissolved solids (TDS), stable oxygen (δ18O) and deuterium (δD) isotopes, spring and seep locations, and prior data are used to gain a preliminary understanding of the shallow groundwater flow in the region. Stable isotope ratios of oxygen (18O/16O) and deuterium (D/H) are used to constrain the source of spring water. Measured δ values are compared to predicted δ values for precipitation from WaterIsotopes.org for each sample site. Measured isotopic values range from -14.9 ‰ to -10.7 ‰ for δ18O and -108 ‰ to -78 ‰ for δD. The majority of samples from above 2000 m match predicted isotopic values for precipitation. Most samples taken below 2000 m are lighter than predicted isotopic values for precipitation. The TDS of spring samples measured in the lab show they range from 184 mg/L to 1552 mg/L with the majority of samples between 220 - 430 mg/L. TDS shows a weak correlation (R2 = 0.54) with altitude, where lower TDS

  5. Numerical modeling of groundwater flow in the coastal aquifer system of Taranto (southern Italy)

    Science.gov (United States)

    De Filippis, Giovanna; Giudici, Mauro; Negri, Sergio; Margiotta, Stefano; Cattaneo, Laura; Vassena, Chiara

    2014-05-01

    The Mediterranean region is characterized by a strong development of coastal areas with a high concentration of water-demanding human activities, resulting in weakly controlled withdrawals of groundwater which accentuate the saltwater intrusion phenomenon. The worsening of groundwater quality is a huge problem especially for those regions, like Salento (southern Italy), where a karst aquifer system represents the most important water resource because of the deficiency of a well developed superficial water supply. In this frame, the first 2D numerical model describing the groundwater flow in the karst aquifer of Salento peninsula was developed by Giudici et al. [1] at the regional scale and then improved by De Filippis et al. [2]. In particular, the estimate of the saturated thickness of the deep aquifer highlighted that the Taranto area is particularly sensitive to the phenomenon of seawater intrusion, both for the specific hydrostratigraphic configuration and for the presence of highly water-demanding industrial activities. These remarks motivate a research project which is part of the research program RITMARE (The Italian Research for the Sea), within which a subprogram is specifically dedicated to the problem of the protection and preservation of groundwater quality in Italian coastal aquifers and in particular, among the others, in the Taranto area. In this context, the CINFAI operative unit aims at providing a contribution to the characterization of groundwater in the study area. The specific objectives are: a. the reconstruction of the groundwater dynamic (i.e., the preliminary identification of a conceptual model for the aquifer system and the subsequent modeling of groundwater flow in a multilayered system which is very complex from the hydrostratigraphical point of view); b. the characterization of groundwater outflows through submarine and subaerial springs and the water exchanges with the shallow coastal water bodies (e.g. Mar Piccolo) and the off

  6. Groundwater flow and tritium migration from the SRS Old Burial Ground to Fourmile Branch

    International Nuclear Information System (INIS)

    Flach, G.P.; Hamm, L.L.; Harris, M.K.

    1996-04-01

    The objectives of this investigation are twofold. The initial goal is to devise and demonstrate a technique for directly incorporating fine-scale lithologic data into heterogeneous hydraulic conductivity fields, for improved groundwater flow and contaminant transport model accuracy. The ultimate goal is to rigorously simulate past and future tritium migration from the SRS Old Burial Ground towards Fourmile Branch, to better understand the effects of various remediation alternatives such as no action and capping. Large-scale variability in hydraulic conductivity is usually the main influence on field-scale groundwater flow patterns and dispersive transport, following the relative locations of recharge and discharge areas. Incorporating realistic hydraulic conductivity heterogeneity into flow and transport models is paramount to accurate simulations, particularly for contaminant migration. Sediment lithologic descriptions and geophysical logs typically offer finer spatial resolution, and therefore more potential information about heterogeneity, than other site characterization data

  7. Evaluation of influence of splay fault growth on groundwater flow around geological disposal system

    International Nuclear Information System (INIS)

    Takai, Shizuka; Takeda, Seiji; Sakai, Ryutaro; Shimada, Taro; Munakata, Masahiro; Tanaka, Tadao

    2017-01-01

    In geological disposal, the direct effect of active faults on geological repositories is avoided at the stage of site characterization, however, uncertainty remains for the avoidance of faults derived from active faults, which are concealed deep under the ground and are difficult to detect by site investigation. In this research, the influence of the growth of undetected splay faults on a natural barrier in a geological disposal system due to the future action of faults was evaluated. We investigated examples of splay faults in Japan and set conditions for the growth of splay faults. Furthermore, we assumed a disposal site composed of sedimentary rock and made a hydrogeological model of the growth of splay faults. We carried out groundwater flow analyses, changing parameters such as the location and depth of the repository and the growth velocity of splay faults. We carried out groundwater flow analyses, changing parameters such as the location and depth of the repository and the growth velocity of splay faults. The results indicate that the main flow path from the repository is changed into an upward flow along the splay fault due to its growth and that the average velocity to the ground surface becomes one or two orders of magnitude higher than that before its growth. The results also suggest that splay fault growth leads to the possibility of the downward flow of oxidizing groundwater from the ground surface area. (author)

  8. Flow pathways in the evolving critical zone - insights from hydraulic groundwater theory

    Science.gov (United States)

    Harman, C. J.; Cosans, C.; Kim, M.

    2017-12-01

    The geochemical signatures of the evolving critical zone are delivered into streams via saturated lateral flow through hillslopes. Here we will draw on hydraulic groundwater theory and scaling arguments to obtain insights into the first-order controls on the transition from vertical infiltration to lateral flow in the critical zone. Hydraulic groundwater theory aims to provide a simplified description of unconfined, saturated groundwater flow in systems that are substantially larger in lateral than vertical extent. The theory rests on the Dupuit assumptions, which are often erroneously stated as including an assumption of exclusively lateral flow. In fact the full three-dimensional flow field can be approximated from these assumptions. Building on this theory, we examine how overall hillslope structure (slope, permeability, convergence/divergence etc.) determines the direction and magnitude of flow in the vicinity of weathering fronts in the critical zone, and how weathering products are delivered to the hillslope base. The results demonstrate that under certain conditions the mere presence of lateral flow will not disturb the lateral symmetry of reaction fronts along the hillslope. Furthermore, coupling to a simple reaction model with porosity/permeability feedback allows us to examine the implications for weathering front advance where saturated lateral flow occurs as a transient perched aquifer at the weathering front. The overall rate of weathering front advance is found to be primarily determined by the component of flow normal to the weathering front, and only significantly accelerated by the lateral component above the weathering front when parent rock permeability is very low.

  9. Flow and geochemistry along shallow ground-water flowpaths in an agricultural area in southeastern Wisconsin

    Science.gov (United States)

    Saad, D.A.; Thorstenson, D.C.

    1998-01-01

    Water-quality and geohydrologic data were collected from 19 monitor wells and a stream in an agricultural area in southeastern Wisconsin. These sites were located along a 2,700-ft transect from a local ground-water high to the stream. The transect is approximately parallel to the horizontal direction of ground-water flow at the water table. Most of the wells were installed in unconsolidated deposits at five locations along the transect and include an upgradient well nest, a midgradient well nest, a downgradient well nest, wells in the lowland area near the stream, and wells installed in the stream bottom. The data collected from this study site were used to describe the water quality and geohydrology of the area and to explain and model the variations in water chemistry along selected ground-water flowpaths.

  10. Groundwater Recharge and Flow Regime revealed by multi-tracers approach in a headwater, North China Plain

    Science.gov (United States)

    Sakakibara, Koichi; Tsujimura, Maki; Song, Xianfang; Zhang, Jie

    2014-05-01

    Groundwater recharge is a crucial hydrological process for effective water management especially in arid/ semi-arid regions. However, the insufficient number of specific research regarding groundwater recharge process has been reported previously. Intensive field surveys were conducted during rainy season, mid dry season, and end of dry season, in order to clarify comprehensive groundwater recharge and flow regime of Wangkuai watershed in a headwater, which is a main recharge zone of North China Plain. The groundwater, spring, stream water and lake water were sampled, and inorganic solute constituents and stable isotopes of oxygen 18 and deuterium were determined on all water samples. Also the stream flow rate was observed. The solute ion concentrations and stable isotopic compositions show that the most water of this region can be characterized by Ca-HCO3 type and the main water source is precipitation which is affected by altitude effect of stable isotopes. In addition, the river and reservoir of the area seem to recharge the groundwater during rainy season, whereas interaction between surface water and groundwater does not become dominant gradually after the rainy season. The inversion analysis applied in Wangkuai watershed using simple mixing model represents an existing multi-flow systems which shows a distinctive tracer signal and flow rate. In summary, the groundwater recharged at different locations in the upper stream of Wangkuai reservoir flows downward to alluvial fan with a certain amount of mixing together, also the surface water recharges certainly the groundwater in alluvial plain in the rainy season.

  11. Knowledge, transparency, and refutability in groundwater models, an example from the Death Valley regional groundwater flow system

    Science.gov (United States)

    Hill, Mary C.; Faunt, Claudia C.; Belcher, Wayne; Sweetkind, Donald; Tiedeman, Claire; Kavetski, Dmitri

    2013-01-01

    This work demonstrates how available knowledge can be used to build more transparent and refutable computer models of groundwater systems. The Death Valley regional groundwater flow system, which surrounds a proposed site for a high level nuclear waste repository of the United States of America, and the Nevada National Security Site (NNSS), where nuclear weapons were tested, is used to explore model adequacy, identify parameters important to (and informed by) observations, and identify existing old and potential new observations important to predictions. Model development is pursued using a set of fundamental questions addressed with carefully designed metrics. Critical methods include using a hydrogeologic model, managing model nonlinearity by designing models that are robust while maintaining realism, using error-based weighting to combine disparate types of data, and identifying important and unimportant parameters and observations and optimizing parameter values with computationally frugal schemes. The frugal schemes employed in this study require relatively few (10–1000 s), parallelizable model runs. This is beneficial because models able to approximate the complex site geology defensibly tend to have high computational cost. The issue of model defensibility is particularly important given the contentious political issues involved.

  12. The movement of groundwater flow in unsaturated fractured porous medium

    International Nuclear Information System (INIS)

    Li Jinxuan

    1995-01-01

    The author analyses the fundamental processes governing infiltration in fractured porous rock. Asymptotic solutions for the front movement are given for each flow period and comparisons with numerical solutions are made. The result of the study is relevant to nuclear waste storage, hazardous waste disposal and petroleum recovery

  13. Determination of filtration velocity and direction of groundwater flow using tracer technique, Port Dickson, Negeri Sembilan

    International Nuclear Information System (INIS)

    Md Shahid Ayub; Roslan Mohd Ali; Kamarudin Samuding

    1996-01-01

    The filtration velocity of the groundwater was determine by introducing I mCi Br-82 into a borehole. Br-82 was in the form of potassium bromide. The result showed that the filtration velocity varies from 2.3 to 4.5 cm/day depending on the soil matrix with the clayey layer posting more resistance to flow. Au-198 in the form of aurium chloride was introduce into two other boreholes to determine the direction of flow. The general trend of flow was in the direction between N140E and N160E

  14. Accurate and efficient calculation of response times for groundwater flow

    Science.gov (United States)

    Carr, Elliot J.; Simpson, Matthew J.

    2018-03-01

    We study measures of the amount of time required for transient flow in heterogeneous porous media to effectively reach steady state, also known as the response time. Here, we develop a new approach that extends the concept of mean action time. Previous applications of the theory of mean action time to estimate the response time use the first two central moments of the probability density function associated with the transition from the initial condition, at t = 0, to the steady state condition that arises in the long time limit, as t → ∞ . This previous approach leads to a computationally convenient estimation of the response time, but the accuracy can be poor. Here, we outline a powerful extension using the first k raw moments, showing how to produce an extremely accurate estimate by making use of asymptotic properties of the cumulative distribution function. Results are validated using an existing laboratory-scale data set describing flow in a homogeneous porous medium. In addition, we demonstrate how the results also apply to flow in heterogeneous porous media. Overall, the new method is: (i) extremely accurate; and (ii) computationally inexpensive. In fact, the computational cost of the new method is orders of magnitude less than the computational effort required to study the response time by solving the transient flow equation. Furthermore, the approach provides a rigorous mathematical connection with the heuristic argument that the response time for flow in a homogeneous porous medium is proportional to L2 / D , where L is a relevant length scale, and D is the aquifer diffusivity. Here, we extend such heuristic arguments by providing a clear mathematical definition of the proportionality constant.

  15. Construction and calibration of a groundwater-flow model to assess groundwater availability in the uppermost principal aquifer systems of the Williston Basin, United States and Canada

    Science.gov (United States)

    Davis, Kyle W.; Long, Andrew J.

    2018-05-31

    The U.S. Geological Survey developed a groundwater-flow model for the uppermost principal aquifer systems in the Williston Basin in parts of Montana, North Dakota, and South Dakota in the United States and parts of Manitoba and Saskatchewan in Canada as part of a detailed assessment of the groundwater availability in the area. The assessment was done because of the potential for increased demands and stresses on groundwater associated with large-scale energy development in the area. As part of this assessment, a three-dimensional groundwater-flow model was developed as a tool that can be used to simulate how the groundwater-flow system responds to changes in hydrologic stresses at a regional scale.The three-dimensional groundwater-flow model was developed using the U.S. Geological Survey’s numerical finite-difference groundwater model with the Newton-Rhapson solver, MODFLOW–NWT, to represent the glacial, lower Tertiary, and Upper Cretaceous aquifer systems for steady-state (mean) hydrological conditions for 1981‒2005 and for transient (temporally varying) conditions using a combination of a steady-state period for pre-1960 and transient periods for 1961‒2005. The numerical model framework was constructed based on existing and interpreted hydrogeologic and geospatial data and consisted of eight layers. Two layers were used to represent the glacial aquifer system in the model; layer 1 represented the upper one-half and layer 2 represented the lower one-half of the glacial aquifer system. Three layers were used to represent the lower Tertiary aquifer system in the model; layer 3 represented the upper Fort Union aquifer, layer 4 represented the middle Fort Union hydrogeologic unit, and layer 5 represented the lower Fort Union aquifer. Three layers were used to represent the Upper Cretaceous aquifer system in the model; layer 6 represented the upper Hell Creek hydrogeologic unit, layer 7 represented the lower Hell Creek aquifer, and layer 8 represented the Fox

  16. Evaluation of bias associated with capture maps derived from nonlinear groundwater flow models

    Science.gov (United States)

    Nadler, Cara; Allander, Kip K.; Pohll, Greg; Morway, Eric D.; Naranjo, Ramon C.; Huntington, Justin

    2018-01-01

    The impact of groundwater withdrawal on surface water is a concern of water users and water managers, particularly in the arid western United States. Capture maps are useful tools to spatially assess the impact of groundwater pumping on water sources (e.g., streamflow depletion) and are being used more frequently for conjunctive management of surface water and groundwater. Capture maps have been derived using linear groundwater flow models and rely on the principle of superposition to demonstrate the effects of pumping in various locations on resources of interest. However, nonlinear models are often necessary to simulate head-dependent boundary conditions and unconfined aquifers. Capture maps developed using nonlinear models with the principle of superposition may over- or underestimate capture magnitude and spatial extent. This paper presents new methods for generating capture difference maps, which assess spatial effects of model nonlinearity on capture fraction sensitivity to pumping rate, and for calculating the bias associated with capture maps. The sensitivity of capture map bias to selected parameters related to model design and conceptualization for the arid western United States is explored. This study finds that the simulation of stream continuity, pumping rates, stream incision, well proximity to capture sources, aquifer hydraulic conductivity, and groundwater evapotranspiration extinction depth substantially affect capture map bias. Capture difference maps demonstrate that regions with large capture fraction differences are indicative of greater potential capture map bias. Understanding both spatial and temporal bias in capture maps derived from nonlinear groundwater flow models improves their utility and defensibility as conjunctive-use management tools.

  17. A General Solution for Groundwater Flow in Estuarine Leaky Aquifer System with Considering Aquifer Anisotropy

    Science.gov (United States)

    Chen, Po-Chia; Chuang, Mo-Hsiung; Tan, Yih-Chi

    2014-05-01

    In recent years the urban and industrial developments near the coastal area are rapid and therefore the associated population grows dramatically. More and more water demand for human activities, agriculture irrigation, and aquaculture relies on heavy pumping in coastal area. The decline of groundwater table may result in the problems of seawater intrusion and/or land subsidence. Since the 1950s, numerous studies focused on the effect of tidal fluctuation on the groundwater flow in the coastal area. Many studies concentrated on the developments of one-dimensional (1D) and two-dimensional (2D) analytical solutions describing the tide-induced head fluctuations. For example, Jacob (1950) derived an analytical solution of 1D groundwater flow in a confined aquifer with a boundary condition subject to sinusoidal oscillation. Jiao and Tang (1999) derived a 1D analytical solution of a leaky confined aquifer by considered a constant groundwater head in the overlying unconfined aquifer. Jeng et al. (2002) studied the tidal propagation in a coupled unconfined and confined costal aquifer system. Sun (1997) presented a 2D solution for groundwater response to tidal loading in an estuary. Tang and Jiao (2001) derived a 2D analytical solution in a leaky confined aquifer system near open tidal water. This study aims at developing a general analytical solution describing the head fluctuations in a 2D estuarine aquifer system consisted of an unconfined aquifer, a confined aquifer, and an aquitard between them. Both the confined and unconfined aquifers are considered to be anisotropic. The predicted head fluctuations from this solution will compare with the simulation results from the MODFLOW program. In addition, the solutions mentioned above will be shown to be special cases of the present solution. Some hypothetical cases regarding the head fluctuation in costal aquifers will be made to investigate the dynamic effects of water table fluctuation, hydrogeological conditions, and

  18. Flow and discharge of groundwater from a snowmelt-affected sandy beach

    Science.gov (United States)

    Chaillou, G.; Lemay-Borduas, F.; Larocque, M.; Couturier, M.; Biehler, A.; Tommi-Morin, G.

    2018-02-01

    The study is based on a complex and unique data set of water stable isotopes (i.e., δ18O and δ2H), radon-222 activities (i.e., 222Rn) and groundwater levels to better understand the interaction of fresh groundwater and recirculated seawater in a snowmelt-affected subterranean estuary (STE) in a boreal region (Îles-de-la-Madeleine, Qc, Canada). By using a combination of hydrogeological and marine geochemical approaches, the objective was to analyze and quantify submarine groundwater discharge processes through a boreal beach after the snow melt period, in early June. The distribution of δ18O and δ2H in beach groundwater showed that inland fresh groundwater contributed between 97 and 30% of water masses presented within the STE. A time series of water table levels during the 16 days of the study indicated that tides propagated as a dynamic wave limiting the mass displacement of seawater within the STE. This up-and-down movement of the water table (∼10-30 cm) induced the vertical infiltration of seawater at the falling tide. At the front of the beach, a radon-based mass balance calculated with high-resolution 222Rn survey estimated total SGD of 3.1 m3/m/d at the discharge zone and a mean flow to 1.5 m3/m/d in the bay. The nearshore discharge agreed relatively well with Darcy fluxes calculated at the beach face. Fresh groundwater makes up more than 50% of the total discharge during the measuring campaign. These results indicate that beaches in boreal and cold regions could be important sources of freshwater originate and groundwater-borne solutes and contaminants to the marine environment after the snowmelt.

  19. Groundwater flow analysis using radon-222 existing in environment as an indicator

    International Nuclear Information System (INIS)

    Komae, Takami

    1996-01-01

    Several kinds of isotopes have been used to trace water movement in the hydrology including surface and ground water as indicators. But those are not effective to analyze the contaminant movement with groundwater though short distance in short time owing to long life. Radon ( 222 Rn) existing in environment was chosen for this purpose as an short-lived indicator. Radon is a radioactive gas, with a half life of 3.8 days, generated from radium ( 226 Ra) in strata. Radon concentration in groundwater increases to reach an equilibrated value within about three weeks after infiltrating underground. The equilibrated concentration becomes an own value of the aquifer depending on the radium content, the grain size and porosity of aquifer. The characteristic makes it able to identify aquifers and sub basins. Since radon concentration in groundwater is 100 to 1000 times as high as that in surface water, groundwater and surface water interaction is quantitatively analyzed. A liquid scintillation counter was employed to measure radon concentration after extracting radon in water to toluene. We applied those advantage of radon-222 to various field investigations and discussed the applicability. It was really possible to analyze the groundwater flow. Monitoring radon concentration in pumped water, occurrences of squeeze and leakage from the different aquifer were detected. Main aquifer was easily determined from the vertical distribution of radon concentration in bore hole. In the injection test using surface water, the spread of injected water was confirmed by the decrease of radon concentration in bore hole water. The radon method was useful to analyze the dam leakage, effluent seepage of groundwater in river, influent seepage of river water underground, and groundwater recharge with irrigation water through unsaturated zone. (author)

  20. Updated comparison of groundwater flow model results and isotopic data in the Leon Valley, Mexico

    Science.gov (United States)

    Hernandez-Garcia, G. D.

    2015-12-01

    Northwest of Mexico City, the study area is located in the State of Guanajuato. Leon Valley has covered with groundwater its demand of water, estimated in 20.6 cubic meters per second. The constant increase of population and economic activities in the region, mainly in cities and automobile factories, has also a constant growth in water needs. Related extraction rate has produced an average decrease of approximately 1.0 m per year over the past two decades. This suggests that the present management of the groundwater should be checked. Management of groundwater in the study area involves the possibility of producing environmental impacts by extraction. This vital resource under stress becomes necessary studying its hydrogeological functioning to achieve scientific management of groundwater in the Valley. This research was based on the analysis and integration of existing information and the field generated by the authors. On the base of updated concepts like the geological structure of the area, the hydraulic parameters and the composition of deuterium-delta and delta-oxygen -18, this research has new results. This information has been fully analyzed by applying a groundwater flow model with particle tracking: the result has also a similar result in terms of travel time and paths derived from isotopic data.

  1. Development of one-dimensional computational fluid dynamics code 'GFLOW' for groundwater flow and contaminant transport analysis

    International Nuclear Information System (INIS)

    Rahatgaonkar, P. S.; Datta, D.; Malhotra, P. K.; Ghadge, S. G.

    2012-01-01

    Prediction of groundwater movement and contaminant transport in soil is an important problem in many branches of science and engineering. This includes groundwater hydrology, environmental engineering, soil science, agricultural engineering and also nuclear engineering. Specifically, in nuclear engineering it is applicable in the design of spent fuel storage pools and waste management sites in the nuclear power plants. Ground water modeling involves the simulation of flow and contaminant transport by groundwater flow. In the context of contaminated soil and groundwater system, numerical simulations are typically used to demonstrate compliance with regulatory standard. A one-dimensional Computational Fluid Dynamics code GFLOW had been developed based on the Finite Difference Method for simulating groundwater flow and contaminant transport through saturated and unsaturated soil. The code is validated with the analytical model and the benchmarking cases available in the literature. (authors)

  2. Development and applications of two finite element groundwater flow and contaminant transport models: FEWA and FEMA

    International Nuclear Information System (INIS)

    Yeh, G.T.; Wong, K.V.; Craig, P.M.; Davis, E.C.

    1985-01-01

    This paper presents the construction, verification, and application of two groundwater flow and contaminant transport models: A Finite Element Model of Water Flow through Aquifers (FEWA) and A Finite Element Model of Material Transport through Aquifers (FEMA). The construction is based on the finite element approximation of partial differential equations of groundwater flow (FEWA) and of solute movement (FEMA). The particular features of FEWA and FEMA are their versatility and flexibility for dealing with nearly all vertically integrated two-dimensional problems. The models were verified against both analytical solutions and widely used US Geological Survey finite difference approximations. They were then applied for calibration and validation, using data obtained in experiments at the Engineering Test Facility at Oak Ridge National Laboratory. Results indicated that the models are valid for this specific site. To demonstrate the versatility anf flexibility of the models, they were applied to two hypothetical, but realistic, complex problems and three field sites across the United States. In these applications the models yielded good agreement with the field data for all three sites. Finally, the predictive capabilities of the models were demonstrated using data obtained at the Hialeah Preston site in Florida. This case illustrates the capability of FEWA and FEMA as predictive tools and their usefulness in the management of groundwater flow and contaminant transport. 25 refs

  3. Simulation of groundwater flow in the glacial aquifer system of northeastern Wisconsin with variable model complexity

    Science.gov (United States)

    Juckem, Paul F.; Clark, Brian R.; Feinstein, Daniel T.

    2017-05-04

    The U.S. Geological Survey, National Water-Quality Assessment seeks to map estimated intrinsic susceptibility of the glacial aquifer system of the conterminous United States. Improved understanding of the hydrogeologic characteristics that explain spatial patterns of intrinsic susceptibility, commonly inferred from estimates of groundwater age distributions, is sought so that methods used for the estimation process are properly equipped. An important step beyond identifying relevant hydrogeologic datasets, such as glacial geology maps, is to evaluate how incorporation of these resources into process-based models using differing levels of detail could affect resulting simulations of groundwater age distributions and, thus, estimates of intrinsic susceptibility.This report describes the construction and calibration of three groundwater-flow models of northeastern Wisconsin that were developed with differing levels of complexity to provide a framework for subsequent evaluations of the effects of process-based model complexity on estimations of groundwater age distributions for withdrawal wells and streams. Preliminary assessments, which focused on the effects of model complexity on simulated water levels and base flows in the glacial aquifer system, illustrate that simulation of vertical gradients using multiple model layers improves simulated heads more in low-permeability units than in high-permeability units. Moreover, simulation of heterogeneous hydraulic conductivity fields in coarse-grained and some fine-grained glacial materials produced a larger improvement in simulated water levels in the glacial aquifer system compared with simulation of uniform hydraulic conductivity within zones. The relation between base flows and model complexity was less clear; however, the relation generally seemed to follow a similar pattern as water levels. Although increased model complexity resulted in improved calibrations, future application of the models using simulated particle

  4. A surrogate-based sensitivity quantification and Bayesian inversion of a regional groundwater flow model

    Science.gov (United States)

    Chen, Mingjie; Izady, Azizallah; Abdalla, Osman A.; Amerjeed, Mansoor

    2018-02-01

    Bayesian inference using Markov Chain Monte Carlo (MCMC) provides an explicit framework for stochastic calibration of hydrogeologic models accounting for uncertainties; however, the MCMC sampling entails a large number of model calls, and could easily become computationally unwieldy if the high-fidelity hydrogeologic model simulation is time consuming. This study proposes a surrogate-based Bayesian framework to address this notorious issue, and illustrates the methodology by inverse modeling a regional MODFLOW model. The high-fidelity groundwater model is approximated by a fast statistical model using Bagging Multivariate Adaptive Regression Spline (BMARS) algorithm, and hence the MCMC sampling can be efficiently performed. In this study, the MODFLOW model is developed to simulate the groundwater flow in an arid region of Oman consisting of mountain-coast aquifers, and used to run representative simulations to generate training dataset for BMARS model construction. A BMARS-based Sobol' method is also employed to efficiently calculate input parameter sensitivities, which are used to evaluate and rank their importance for the groundwater flow model system. According to sensitivity analysis, insensitive parameters are screened out of Bayesian inversion of the MODFLOW model, further saving computing efforts. The posterior probability distribution of input parameters is efficiently inferred from the prescribed prior distribution using observed head data, demonstrating that the presented BMARS-based Bayesian framework is an efficient tool to reduce parameter uncertainties of a groundwater system.

  5. Simulation of groundwater and surface-water flow in the upper Deschutes Basin, Oregon

    Science.gov (United States)

    Gannett, Marshall W.; Lite, Kenneth E.; Risley, John C.; Pischel, Esther M.; La Marche, Jonathan L.

    2017-10-20

    This report describes a hydrologic model for the upper Deschutes Basin in central Oregon developed using the U.S. Geological Survey (USGS) integrated Groundwater and Surface-Water Flow model (GSFLOW). The upper Deschutes Basin, which drains much of the eastern side of the Cascade Range in Oregon, is underlain by large areas of permeable volcanic rock. That permeability, in combination with the large annual precipitation at high elevations, results in a substantial regional aquifer system and a stream system that is heavily groundwater dominated.The upper Deschutes Basin is also an area of expanding population and increasing water demand for public supply and agriculture. Surface water was largely developed for agricultural use by the mid-20th century, and is closed to additional appropriations. Consequently, water users look to groundwater to satisfy the growing demand. The well‑documented connection between groundwater and the stream system, and the institutional and legal restrictions on streamflow depletion by wells, resulted in the Oregon Water Resources Department (OWRD) instituting a process whereby additional groundwater pumping can be permitted only if the effects to streams are mitigated, for example, by reducing permitted surface-water diversions. Implementing such a program requires understanding of the spatial and temporal distribution of effects to streams from groundwater pumping. A groundwater model developed in the early 2000s by the USGS and OWRD has been used to provide insights into the distribution of streamflow depletion by wells, but lacks spatial resolution in sensitive headwaters and spring areas.The integrated model developed for this project, based largely on the earlier model, has a much finer grid spacing allowing resolution of sensitive headwater streams and important spring areas, and simulates a more complete set of surface processes as well as runoff and groundwater flow. In addition, the integrated model includes improved

  6. Construction of a groundwater-flow model for the Big Sioux Aquifer using airborne electromagnetic methods, Sioux Falls, South Dakota

    Science.gov (United States)

    Valder, Joshua F.; Delzer, Gregory C.; Carter, Janet M.; Smith, Bruce D.; Smith, David V.

    2016-09-28

    The city of Sioux Falls is the fastest growing community in South Dakota. In response to this continued growth and planning for future development, Sioux Falls requires a sustainable supply of municipal water. Planning and managing sustainable groundwater supplies requires a thorough understanding of local groundwater resources. The Big Sioux aquifer consists of glacial outwash sands and gravels and is hydraulically connected to the Big Sioux River, which provided about 90 percent of the city’s source-water production in 2015. Managing sustainable groundwater supplies also requires an understanding of groundwater availability. An effective mechanism to inform water management decisions is the development and utilization of a groundwater-flow model. A groundwater-flow model provides a quantitative framework for synthesizing field information and conceptualizing hydrogeologic processes. These groundwater-flow models can support decision making processes by mapping and characterizing the aquifer. Accordingly, the city of Sioux Falls partnered with the U.S. Geological Survey to construct a groundwater-flow model. Model inputs will include data from advanced geophysical techniques, specifically airborne electromagnetic methods.

  7. Heat flow and subsurface temperature as evidence for basin-scale ground-water flow, North Slope of Alaska

    Science.gov (United States)

    Deming, D.; Sass, J.H.; Lachenbruch, A.H.; De Rito, R. F.

    1992-01-01

    Several high-resolution temperature logs were made in each of 21 drillholes and a total of 601 thermal conductivity measurements were made on drill cuttings and cores. Near-surface heat flow (??20%) is inversely correlated with elevation and ranges from a low of 27 mW/m2 in the foothills of the Brooks Range in the south, to a high of 90 mW/m2 near the north coast. Subsurface temperatures and thermal gradients estimated from corrected BHTs are similarly much higher on the coastal plain than in the foothills province to the south. Significant east-west variation in heat flow and subsurface temperature is also observed; higher heat flow and temperature coincide with higher basement topography. The observed thermal pattern is consistent with forced convection by a topographically driven ground-water flow system. Average ground-water (Darcy) velocity in the postulated flow system is estimated to be of the order of 0.1 m/yr; the effective basin-scale permeability is estimated to be of the order of 10-14 m2. -from Authors

  8. Use of MICRAS code on the evaluation of the maximum radionuclides concentrations due to transport/migration of decay chain in groundwaters

    International Nuclear Information System (INIS)

    Aquino Branco, O.E. de

    1995-01-01

    This paper presents a methodology for the evaluation of the maximum radionuclides concentrations in groundwaters, due to the transport/migration of decay chains. Analytical solution of the equations system is difficult, even if only three elements of the decay chain are considered. Therefore, a numerical solution is most convenient. An application of the MICRAS code, developed to assess maximum concentrations of each radionuclide, starting with the initial concentrations, is presented. The maximum concentration profile for 226 Ra, calculated using MICRAS, is compared with the results obtained through an analytical and a numerical model. The fitness of results is considered good. Simplified models, like the one represented by the application of MICRAS, are largely employed in the section in the selection and characterization of sites for radioactive wastes repositories and in studies of safety evaluation for the same purpose. A detailed analysis of the transport/migration of contaminants in aquifers requires a large quantify of data from the site and from the installation as well, which makes this analysis expensive and inviable during the preliminary phases of the studies. (author). 6 refs, 1 fig, 1 tab

  9. Water and rock geochemistry, geologic cross sections, geochemical modeling, and groundwater flow modeling for identifying the source of groundwater to Montezuma Well, a natural spring in central Arizona

    Science.gov (United States)

    Johnson, Raymond H.; DeWitt, Ed; Wirt, Laurie; Arnold, L. Rick; Horton, John D.

    2011-01-01

    The National Park Service (NPS) seeks additional information to better understand the source(s) of groundwater and associated groundwater flow paths to Montezuma Well in Montezuma Castle National Monument, central Arizona. The source of water to Montezuma Well, a flowing sinkhole in a desert setting, is poorly understood. Water emerges from the middle limestone facies of the lacustrine Verde Formation, but the precise origin of the water and its travel path are largely unknown. Some have proposed artesian flow to Montezuma Well through the Supai Formation, which is exposed along the eastern margin of the Verde Valley and underlies the Verde Formation. The groundwater recharge zone likely lies above the floor of the Verde Valley somewhere to the north or east of Montezuma Well, where precipitation is more abundant. Additional data from groundwater, surface water, and bedrock geology are required for Montezuma Well and the surrounding region to test the current conceptual ideas, to provide new details on the groundwater flow in the area, and to assist in future management decisions. The results of this research will provide information for long-term water resource management and the protection of water rights.

  10. Groundwater, springs, and stream flow generation in an alpine meadow of a tropical glacierized catchment

    Science.gov (United States)

    Gordon, R.; Lautz, L. K.; McKenzie, J. M.; Mark, B. G.; Chavez, D.

    2013-12-01

    Melting tropical glaciers supply approximately half of dry season stream discharge in glacierized valleys of the Cordillera Blanca, Peru. The remainder of streamflow originates as groundwater stored in alpine meadows, moraines and talus slopes. A better understanding of the dynamics of alpine groundwater, including sources and contributions to streamflow, is important for making accurate estimates of glacial inputs to the hydrologic budget, and for our ability to make predictions about future water resources as glaciers retreat. Our field study, conducted during the dry season in the Llanganuco valley, focused on a 0.5-km2 alpine meadow complex at 4400 m elevation, which includes talus slopes, terminal moraines, and a debris fan. Two glacial lakes and springs throughout the complex feed a network of stream channels that flow across the meadow (~2 km total length). We combined tracer measurements of stream and spring discharge and groundwater-surface water exchange with synoptic sampling of water isotopic and geochemical composition, in order to characterize and quantify contributions to streamflow from different geomorphic features. Surface water inputs to the stream channels totaled 58 l/s, while the stream gained an additional 57 l/s from groundwater inputs. Water chemistry is primarily controlled by flowpath type (surface/subsurface) and length, as well as bedrock lithology, while stable water isotopic composition appears to be controlled by water source (glacial lake, meadow or deep groundwater). Stream water chemistry is most similar to meadow groundwater springs, but isotopic composition suggests that the majority of stream water, which issues from springs at the meadow/fan interface, is from the same glacial source as the up-gradient lake. Groundwater sampled from piezometers in confined meadow aquifers is unique in both chemistry and isotopic composition, but does not contribute a large percentage of stream water exiting this small meadow, as quantified by

  11. Review of data requirements for groundwater flow and solute transport modelling and the ability of site investigation methods to meet these requirements

    International Nuclear Information System (INIS)

    McEwen, T.J.; Chapman, N.A.; Robinson, P.C.

    1990-08-01

    This report describes the data requirements for the codes that may be used in the modelling of groundwater flow and radionuclide transport during the assessment of a Nirex site for the deep disposal of low and intermediate level radioactive waste and also the site investigation methods that exist to supply the data for these codes. The data requirements for eight codes are reviewed, with most emphasis on three of the more significant codes, VANDAL, NAMMU and CHEMTARD. The largest part of the report describes and discusses the site investigation techniques and each technique is considered in terms of its ability to provide the data necessary to characterise the geological and hydrogeological environment around a potential repository. (author)

  12. Groundwater flow modelling under ice sheet conditions in Greenland (phase II)

    International Nuclear Information System (INIS)

    Jaquet, Olivier; Namar, Rabah; Siegel, Pascal; Jansson, Peter

    2012-11-01

    Within the framework of the GAP project, this second phase of geosphere modelling has enabled the development of an improved regional model that has led to a better representation of groundwater flow conditions likely to occur under ice sheet conditions. New data in relation to talik geometry and elevation, as well as to deformation zones were integrated in the geosphere model. In addition, more realistic hydraulic properties were considered for geosphere modelling; they were taken from the Laxemar site in Sweden. The geological medium with conductive deformation zones was modelled as a 3D continuum with stochastically hydraulic properties. Surface and basal glacial meltwater rates provided by a dynamic ice sheet model were assimilated into the groundwater flow model using mixed boundary conditions. The groundwater flow system is considered to be governed by infiltration of glacial meltwater in heterogeneous faulted crystalline rocks in the presence of permafrost and taliks. The characterisation of the permafrost-depth distribution was achieved using a coupled description of flow and heat transfer under steady state conditions. Using glaciological concepts and satellite data, an improved stochastic model was developed for the description at regional scale for the subglacial permafrost distribution in correlation with ice velocity and bed elevation data. Finally, the production of glacial meltwater by the ice sheet was traced for the determination of its depth and lateral extent. The major improvements are related to the type and handling of the subglacial boundary conditions. The use of meltwater rates provided by an ice sheet model applied as input to a mixed boundary condition enables to produce a more plausible flow field in the Eastern part of the domain, in comparison to previous modelling results (Jaquet et al. 2010). In addition, the integration of all potential taliks within the modelled domain provides a better characterisation of the likely groundwater

  13. Groundwater flow modelling under ice sheet conditions in Greenland (phase II)

    Energy Technology Data Exchange (ETDEWEB)

    Jaquet, Olivier; Namar, Rabah; Siegel, Pascal [In2Earth Modelling Ltd, Lausanne (Switzerland); Jansson, Peter [Dept. of Physical Geography and Quaternary Geology, Stockholm Univ., Stockholm (Sweden)

    2012-11-15

    Within the framework of the GAP project, this second phase of geosphere modelling has enabled the development of an improved regional model that has led to a better representation of groundwater flow conditions likely to occur under ice sheet conditions. New data in relation to talik geometry and elevation, as well as to deformation zones were integrated in the geosphere model. In addition, more realistic hydraulic properties were considered for geosphere modelling; they were taken from the Laxemar site in Sweden. The geological medium with conductive deformation zones was modelled as a 3D continuum with stochastically hydraulic properties. Surface and basal glacial meltwater rates provided by a dynamic ice sheet model were assimilated into the groundwater flow model using mixed boundary conditions. The groundwater flow system is considered to be governed by infiltration of glacial meltwater in heterogeneous faulted crystalline rocks in the presence of permafrost and taliks. The characterisation of the permafrost-depth distribution was achieved using a coupled description of flow and heat transfer under steady state conditions. Using glaciological concepts and satellite data, an improved stochastic model was developed for the description at regional scale for the subglacial permafrost distribution in correlation with ice velocity and bed elevation data. Finally, the production of glacial meltwater by the ice sheet was traced for the determination of its depth and lateral extent. The major improvements are related to the type and handling of the subglacial boundary conditions. The use of meltwater rates provided by an ice sheet model applied as input to a mixed boundary condition enables to produce a more plausible flow field in the Eastern part of the domain, in comparison to previous modelling results (Jaquet et al. 2010). In addition, the integration of all potential taliks within the modelled domain provides a better characterisation of the likely groundwater

  14. Influence of faults on groundwater flow and transport at Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Cohen, Andrew J.B.; Sitar, Nicholas

    1999-01-01

    Numerical simulations of groundwater flow at Yucca Mountain, Nevada are used to investigate how faults influence groundwater flow pathways and regional-scale macrodispersion. The 3-D model has a unique grid block discretization that facilitates the accurate representation of the complex geologic structure present in faulted formations. Each hydrogeologic layer is discretized into a single layer of irregular and dipping grid blocks, and faults are discretized such that they are laterally continuous and varied in displacement varies along strike. In addition, the presence of altered fault zones is explicitly modeled, as appropriate. Simulations show that upward head gradients can be readily explained by the geometry of hydrogeologic layers, the variability of layer permeabilities, and the presence of permeable fault zones or faults with displacement only, not necessarily by upwelling from a deep aquifer. Large-scale macrodispersion results from the vertical and lateral diversion of flow near the contact of high- and low-permeability layers at faults, and from upward flow within high-permeability fault zones. Conversely, large-scale channeling can occur as a result of groundwater flow into areas with minimal fault displacement. Contaminants originating at the water table can flow in a direction significantly different from that of the water table gradient, and isolated zones of contaminants can occur at the water table downgradient. By conducting both 2-D and 3-D simulations, we show that the 2-D cross-sectional models traditionally used to examine flow in faulted formations may not be appropriate. In addition, the influence of a particular type of fault cannot be generalized; depending on the location where contaminants enter the saturated zone, faults may either enhance or inhibit vertical dispersion

  15. A scalable approach to modeling groundwater flow on massively parallel computers