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Sample records for 72-hour aquifer test

  1. Preservation of Isolated Heart for 72 Hours

    PubMed Central

    Proctor, E.; Parker, R.

    1968-01-01

    Isolated hearts of dogs have been preserved in a viable condition for 72 hours with hypothermic perfusion (5° C.) at normal atmospheric pressure. On removal and connexion to the femoral artery and vein of another dog these hearts beat strongly and without failing until removed after six hours. In mechanical function and histological appearance they were virtually identical with control hearts. The most useful criterion of viability of the quiescent myocardium during storage was the change in coronary resistance with time of perfusion. ImagesFig. 2 PMID:4879972

  2. Summary of hydrologic testing of the Floridan aquifer system at Fort Stewart, coastal Georgia, 2009-2010

    USGS Publications Warehouse

    Gonthier, Gerald J.

    2011-01-01

    Two test wells were completed at Fort Stewart, coastal Georgia, to investigate the potential for using the Lower Floridan aquifer as a source of water to satisfy anticipated, increased water needs. The U.S. Geological Survey, in cooperation with the U.S. Department of the Army, completed hydrologic testing of the Floridan aquifer system at the study site, including flowmeter surveys, slug tests, and 24- and 72-hour aquifer tests by mid-March 2010. Analytical approaches and model simulation were applied to aquifer-test results to provide estimates of transmissivity and hydraulic conductivity of the multilayered Floridan aquifer system. Data from a 24-hour aquifer test of the Upper Floridan aquifer were evaluated by using the straight-line Cooper-Jacob analytical method. Data from a 72-hour aquifer test of the Lower Floridan aquifer were simulated by using axisymmetric model simulations. Results of aquifer testing indicated that the Upper Floridan aquifer has a transmissivity of 100,000 feet-squared per day, and the Lower Floridan aquifer has a transmissivity of 7,000 feet-squared per day. A specific storage for the Floridan aquifer system as a result of model calibration was 3E-06 ft–1. Additionally, during a 72-hour aquifer test of the Lower Floridan aquifer, a drawdown response was observed in two Upper Floridan aquifer wells, one of which was more than 1 mile away from the pumped well.

  3. Aquifer-test analysis of the upper aquifer of the Potomac-Raritan- Magothy aquifer system, Union Beach Borough, Monmouth County, New Jersey

    USGS Publications Warehouse

    Pucci, A.A.; Pope, D.A.; Ivahnenko, Tamara

    1989-01-01

    The hydraulic properties of the upper aquifer of the Potomac-Raritan-Magothy aquifer system and of the overlying and underlying confining units were determined from and aquifer test in the vicinity of Union Beach Borough, New Jersey, near Raritan Bay. The April 1986 test included the pumping of 2 test wells for 72 hours at a combined discharge rate of 1,375 gal/min, and the measurement of water levels in 10 observation wells. No lateral recharge boundary in Raritan Bay affected the observed water-level changes. Assuming leaky artesian conditions, the average transmissivity and storage coefficient of the upper aquifer are 7,754 sq ft/day and 0.00044 respectively. The leakance of the combined confining units ranges from 0.000030 to 0.000076/day/ft. On the basis of lithologic samples from a nearby well, the overlying and underlying confining units were assumed to have similar hydraulic properties. By using this assumption, the vertical hydraulic conductivity of the confining units ranges from 0.010 to 0.027 ft/day. (USGS)

  4. Aquifer test at well SMW-1 near Moenkopi, Arizona

    USGS Publications Warehouse

    Carruth, Robert L.; Bills, Donald J.

    2012-01-01

    surface. A 9.25-hour step-drawdown test and a 72-hour constant-rate test followed by recovery tests were used to investigate the performance of the test well and to estimate the transmissivity and potential yield of the N aquifer south of Moenkopi Wash. The test data were analyzed using the Cooper-Jacob method adjusted for confined conditions, the Papadopulos-Cooper method that accounts for wellbore storage, and the Theis method on the recovery data. Results of the tests indicate that in the vicinity of the well, the N aquifer has a transmissivity of about 50 feet squared per day. The test well, as completed, should yield about 15 gallons per minute with about 75 feet of drawdown (less than half of the available saturated thickness of the aquifer at the well).

  5. Integrating borehole logs and aquifer tests in aquifer characterization

    USGS Publications Warehouse

    Paillet, Frederick L.; Reese, R.S.

    2000-01-01

    Integration of lithologic logs, geophysical logs, and hydraulic tests is critical in characterizing heterogeneous aquifers. Typically only a limited number of aquifer tests can be performed, and these need to be designed to provide hydraulic properties for the principle aquifers in the system. This study describes the integration of logs and aquifer tests in the development of a hydrostratigraphic model for the surficial aquifer system in and around Big Cypress National Preserve in eastern Collier County, Florida. Borehole flowmeter tests provide qualitative permeability profiles in most of 26 boreholes drilled in the Study area. Flow logs indicate the depth of transmissive units, which are correlated across the study area. Comparison to published studies in adjacent areas indicates that the main limestone aquifer of the 000000Tamiami Formation in the study area corresponds with the gray limestone aquifer in western Dade County and the water table and lower Tamiami Aquifer in western Collier County. Four strategically located, multiwell aquifer tests are used to quantify the qualitative permeability profiles provided by the flowmeter log analysis. The hydrostratigraphic model based on these results defines the main aquifer in the central part of the study area as unconfined to semiconfined with a transmissivity as high as 30,000 m2/day. The aquifer decreases in transmissivity to less than 10,000 m2/day in some parts of western Collier County, and becomes confined to the east and northeast of the study area, where transmissivity decreases to below 5000 m2/day.Integration of lithologic logs, geophysical logs, and hydraulic tests is critical in characterizing heterogeneous aquifers. Typically only a limited number of aquifer tests can be performed, and these need to be designed to provide hydraulic properties for the principle aquifers in the system. This study describes the integration of logs and aquifer tests in the development of a hydrostratigraphic model for the

  6. Summary of hydrologic testing of the Floridan aquifer system at Hunter Army Airfield, Chatham County, Georgia

    USGS Publications Warehouse

    Williams, Lester J.

    2010-01-01

    indicated the Upper Floridan aquifer had a transmissivity of 40,000 feet squared per day, and the Lower Floridan aquifer had a transmissivity of 10,000 feet squared per day. An aquifer test conducted on the combined aquifer system, when the test well was open from 333 to 1,112 feet, gave a transmissivity of 50,000 feet squared per day. Additionally, during the 72-hour test of the Lower Floridan aquifer, a drawdown response was observed in the Upper Floridan aquifer wells.

  7. Aquifer test to determine hydraulic properties of the Elm aquifer near Aberdeen, South Dakota

    USGS Publications Warehouse

    Schaap, Bryan D.

    2000-01-01

    The Elm aquifer, which consists of sandy and gravelly glacial-outwash deposits, is present in several counties in northeastern South Dakota. An aquifer test was conducted northeast of Aberdeen during the fall of 1999 to determine the hydraulic properties of the Elm aquifer in that area. An improved understanding of the properties of the aquifer will be useful in the possible development of the aquifer as a water resource. Historical water-level data indicate that the saturated thickness of the Elm aquifer can change considerably over time. From September 1977 through November 1985, water levels at three wells completed in the Elm aquifer near the aquifer test site varied by 5.1 ft, 9.50 ft, and 11.1 ft. From June 1982 through October 1999, water levels at five wells completed in the Elm aquifer near the aquifer test site varied by 8.7 ft, 11.4 ft, 13.2 ft, 13.8 ft, and 19.7 ft. The water levels during the fall of 1999 were among the highest on record, so the aquifer test was affected by portions of the aquifer being saturated that might not be saturated during drier times. The aquifer test was conducted using five existing wells that had been installed prior to this study. Well A, the pumped well, has an operating irrigation pump and is centrally located among the wells. Wells B, C, D, and E are about 70 ft, 1,390 ft, 2,200 ft, and 3,100 ft, respectively, in different directions from Well A. Using vented pressure transducers and programmable data loggers, water-level data were collected at the five wells prior to, during, and after the pumping, which started on November 19, 1999, and continued a little over 72 hours. Based on available drilling logs, the Elm aquifer near the test area was assumed to be unconfined. The Neuman (1974) method theoretical response curves that most closely match the observed water-level changes at Wells A and B were calculated using software (AQTESOLV for Windows Version 2.13-Professional) developed by Glenn M. Duffield of Hydro

  8. 72 hours standby time of wet-primed cardiopulmonary bypass circuits: a microbiological quality assurance study.

    PubMed

    Schulz-Stübner, Sebastian; Schorer, Cornelia; Ennker, Jürgen; Bauer, Stefan; Schaumann, Reiner

    2014-10-01

    In a microbiological sample study of 15 wet-primed cardiopulmonary bypass circuits in standby mode for 72 hours under regular clinical conditions, no contamination of the priming fluid or the connectors could be detected. Hand contact surfaces of the machines demonstrated environmental microorganisms. These findings indicate the safe use of primed cardiopulmonary bypass circuits in standby mode for 72 hours. A surface disinfection of hand contact surfaces immediately before use is recommended. PMID:24788708

  9. Understanding Why Patients Return to the Emergency Department after Mild Traumatic Brain Injury within 72 Hours

    PubMed Central

    Ganti, Latha; Conroy, Lauren M.; Bodhit, Aakash; Daneshvar, Yasamin; Patel, Pratik Shashikant; Ayala, Sarah; Kuchibhotla, Sudeep; Hatchitt, Kelsey; Pulvino, Christa; Peters, Keith R.; Lottenberg, Lawrence L.

    2015-01-01

    Introduction Although there are approximately 1.1 million case presentations of mild traumatic brain injury (mTBI) in the emergency department (ED) each year, little data is available to clinicians to identify patients who are at risk for poor outcomes, including 72-hour ED return after discharge. An understanding of patients at risk for ED return visits during the hyperacute phase following head injury would allow ED providers to develop clinical interventions that reduce its occurrence and improve outcomes. Methods This institutional review board-approved consecutive cohort study collected injury and outcome variables on adults with the purpose of identifying positive predictors for 72-hour ED return visits in mTBI patients. Results Of 2,787 mTBI patients, 145 (5%) returned unexpectedly to the ED within 72 hours of hospital discharge. Positive predictors for ED return visits included being male (p=0.0298), being black (p=0.0456), having a lower prehospital Glasgow Coma Score (p=0.0335), suffering the injury due to a motor vehicle collision (p=0.0065), or having a bleed on head computed tomography (CT) (p=0.0334). ED return visits were not significantly associated with age, fracture on head CT, or symptomology following head trauma. Patients with return visits most commonly reported post-concussion syndrome (43.1%), pain (18.7%), and recall for further clinical evaluation (14.6%) as the reason for return. Of the 124 patients who returned to the ED within 72 hours, one out of five were admitted to the hospital for further care, with five requiring intensive care unit stays and four undergoing neurosurgery. Conclusion Approximately 5% of adult patients who present to the ED for mTBI will return within 72 hours of discharge for further care. Clinicians should identify at-risk individuals during their initial visits and attempt to provide anticipatory guidance when possible. PMID:25987933

  10. Summary of hydrologic testing of the Floridan aquifer system at Fort Stewart, Georgia

    USGS Publications Warehouse

    Gonthier, Gerard J.

    2011-01-01

    Flowmeter surveys at the study site indicate several permeable zones within the Floridan aquifer system. The Upper Floridan aquifer is composed of two water-bearing zones-the upper zone and the lower zone. The upper zone extends from 520 to 650 feet below land surface, contributes 96 percent of the total flow, and is more permeable than the lower zone, which extends from 650 to 705 feet below land surface and contributes the remaining 4 percent of the flow. The Lower Floridan aquifer consists of three zones at depths of 912-947, 1,090-1,139, and 1,211-1,250 feet below land surface that are inter-layered with three less-permeable zones. The Lower Floridan confining unit includes a permeable zone that extends from 793 to 822 feet below land surface. Horizontal hydraulic conductivity values of the Lower Floridan confining unit derived from slug tests within four packer-isolated intervals were from 2 to 20 feet per day, with a high value of 70 feet per day obtained for one of the intervals. Aquifer testing, using analytical techniques and model simulation, indicated the Upper Floridan aquifer had a transmissivity of about 100,000 feet squared per day, and the Lower Floridan aquifer had a transmissivity of 7,000 feet squared per day. Flowmeter surveys, slug tests within packer-isolated intervals, and parameter-estimation results indicate that the hydraulic properties of the Lower Floridan confining unit are similar to those of the Lower Floridan aquifer. Water-level data, for each aquifer test, were filtered for external influences such as barometric pressure, earth-tide effects, and long-term trends to enable detection of small water-level responses to aquifer-test pumping of less than 1 foot. During a 72-hour aquifer test of the Lower Floridan aquifer, a drawdown response of 0.3 to 0.4 foot was observed in two Upper Floridan aquifer wells, one of which was more than 1 mile away from the pumped well.

  11. Statistical analysis of aquifer-test results for nine regional aquifers in Louisiana

    USGS Publications Warehouse

    Martin, Angel; Early, D.A.

    1987-01-01

    This report, prepared as part of the Gulf Coast Regional Aquifer-System Analysis project, presents a compilation, summarization, and statistical analysis of aquifer-test results for nine regional aquifers in Louisiana. These are from youngest to oldest: The alluvial, Pleistocene, Evangeline, Jasper, Catahoula, Cockfield, Sparta, Carrizo, and Wilcox aquifers. Approximately 1,500 aquifer tests in U.S. Geological Survey files in Louisiana were examined and 1,001 were input to a computer file. Analysis of the aquifer test results and plots that describe aquifer hydraulic characteristics were made for each regional aquifer. Results indicate that, on the average, permeability (hydraulic conductivity) generally tends to decrease from the youngest aquifers to the oldest. The most permeable aquifers in Louisiana are the alluvial and Pleistocene aquifers; whereas, the least permeable are the Carrizo and Wilcox aquifers. (Author 's abstract)

  12. Aquifer test results, Green Swamp area, Florida

    USGS Publications Warehouse

    Tibbals, C.H.; Grubb, Hayes F.

    1982-01-01

    An aquifer test conducted in the Green Swamp area December 15-16 , 1975 was designed to stress the uppermost part of the Floridan aquifer so that the leakage characteristics of the overlying confining bed could be determined. A well tapping the upper part of the Floridan aquifer was pumped at a rate of about 1,040 gallons per minute for 35 hours; drawdown was measured in the Floridan aquifer and in two horizons in the confining bed. Analysis of the data indicates that the transmissivity of the uppper 160 feet of the Floridan is 13,000 square feet per day, the storage coefficient is about 0.0002.5, and the overlying confining bed leakance coefficient is about 0.02 to 0.025 per day. The vertical hydraulic diffusivity of the confining bed ranged from 610 square feet per day to 16,000 square feet per day. Results of the test indicate that, in the area of the test site, a Floridan aquifer well field would induce additional recharge to the Floridan. As a result of that increased recharge , water levels in the surficial aquifer would tend to stand lower, runoff from the area would tend to be less, and, perhaps, evapotranspiration would be less than normal.(USGS)

  13. Understanding Emergency Department 72-Hour Revisits Among Medicaid Patients Using Electronic Healthcare Records.

    PubMed

    Ryan, James; Hendler, James; Bennett, Kristin P

    2015-12-01

    Electronic Healthcare Records (EHRs) have the potential to improve healthcare quality and to decrease costs by providing quality metrics, discovering actionable insights, and supporting decision-making to improve future outcomes. Within the United States Medicaid Program, rates of recidivism among emergency department (ED) patients serve as metrics of hospital performance that help ensure efficient and effective treatment within the ED. We analyze ED Medicaid patient data from 1,149,738 EHRs provided by a hospital over a 2-year period to understand the characteristics of the ED return visits within a 72-hour time frame. Frequent flyer patients with multiple revisits account for 47% of Medicaid patient revisits over this period. ED encounters by frequent flyer patients with prior 72-hour revisits in the last 6 months are thrice more likely to result in a readmit than those of infrequent patients. Statistical L1-logistic regression and random forest analyses reveal distinct patterns of ED usage and patient diagnoses between frequent and infrequent patient encounters, suggesting distinct opportunities for interventions to improve efficacy of care and streamline ED workflow. This work forms a foundation for future development of predictive models, which could flag patients at high risk of revisiting.

  14. Characteristics of patients who made a return visit within 72 hours to the emergency department of a Singapore tertiary hospital

    PubMed Central

    Chan, Amy Hui Sian; Ho, Shu Fang; Fook-Chong, Stephanie Man Chung; Lian, Sherman Wei Qiang; Liu, Nan; Ong, Marcus Eng Hock

    2016-01-01

    INTRODUCTION 72-hour emergency department (ED) reattendance is a widely-used quality indicator for quality of care and patient safety. It is generally assumed that patients who return within 72 hours of ED discharge (72-hour re-attendees) received inadequate treatment or evaluation. The current literature also suggests considerable variation in probable causes of 72-hour ED reattendances internationally. This study aimed to understand the characteristics of these patients at the ED of a Singapore tertiary hospital. METHODS We conducted a retrospective cohort study on all ED visits between 1 January 2013 and 31 December 2013. 72-hour re-attendees were compared against non-re-attendees based on patient demographics, mode of arrival, patient acuity category status (i.e. P1/P2/P3/P4), seniority ranking of doctor-in-charge and medical diagnoses. Multivariate analysis using the generalised linear model was conducted on variables associated with 72-hour ED re-attendance. RESULTS Among 104,751 unique patients, 3,065 (2.93%) were in the 72-hour re-attendees group. Multivariate analysis showed that the following risk factors were associated with higher risk of returning within 72 hours: male gender, older age, arrival by ambulance, triaged as P2, diagnoses of heart problems, abdominal pain or viral infection (all p < 0.001), and Chinese ethnicity (p = 0.006). There was no significant difference in the seniority ranking of the doctor-in-charge between both groups (p = 0.419). CONCLUSION Several patient and event factors were associated with higher risk of being a 72-hour re-attendee. This study forms the basis for hypothesis generation and further studies to explore reasons behind reattendances so that interventions can be developed to target high-risk groups. PMID:27353286

  15. Suicide Within 72 Hours After Discharge From Health Care Settings: Decedent Characteristics.

    PubMed

    Drake, Stacy A; Garza, Brenda; Cron, Stanley G; Wolf, Dwayne A

    2016-03-01

    Health care providers have the challenge of identifying patients at risk of committing suicide after discharge from their care. The aim of this study was to identify and describe the population committing suicide less than 72 hours after discharge from medical care. Between 2006 and 2014 in Harris County, Texas, 30 individuals were identified who met these criteria. The decedents included 27 men and 3 women with a mean age of 43.5 years. The cause of death in most cases was gunshot wound of the head. Five of the decedents had requested discharge or left against medical advice and 24 committed suicide within 24 hours. Although the sample size is small, it is one of the largest cohorts of its type. PMID:26600232

  16. Operational Solar Forecasting System for DNI and GHI for Horizons Covering 5 Minutes to 72 Hours

    NASA Astrophysics Data System (ADS)

    Coimbra, C. F.

    2014-12-01

    I will describe the methodology used to develop and deploy operationally a comprehensive solar forecasting system for both concentrated and non-concentrated solar technologies. This operational forecasting system ingests data from local telemetry, remote sensing and Numerical Weather Prediction (NWP) models, processes all the diferent types of data (time series, sky images, satellite images, gridded data, etc.) to produce concatenated solar forecasts from 5 minutes out to 72 hours into the future. Each forecast is optimized with stochastic learning techniques that include input selection, model topology optimization, model output statistics, metric fitness optimization and machine learning. These forecasts are used by solar generators (plant managers), utilities and independent system operators for operations, scheduling, dispatching and market participation.

  17. Floral Inhibition of Biloxi Soybean During a 72-hour Cycle 1

    PubMed Central

    Shumate, W. H.; Reid, H. B.; Hamner, K. C.

    1967-01-01

    The inhibitory effect of light interruptions given during the photophobe phases of a 72-hour cycle was studied with Biloxi soybean [Glycine max (L.) Merr.]. The basic 72-hour cycle consisted of 8 hours of light followed by 64 hours of darkness and was repeated 7 times. Supplementary white light treatments given at the twenty-fourth and/or forty-eighth hour of the cycle (photophil phases) promoted the flowering levels of the controls and kept light treatments given at the most inhibitory points from inhibiting flowering completely. Such supplementary light treatments did not affect the time of maximum sensitivity to light interruptions. When 30-minute light breaks were used, maximum inhibition occurred at the 16-, 43-, and 63-hour points. The duration of the light breaks affected the time of maximum inhibition when given during the second photophobe phase. The time of maximum inhibition occurred earlier with 4-hour light breaks than with either 3-minute or 2-hour light interruptions. Three-minute red light interruptions produced essentially the same effect as 3-minute white light interruptions. Such treatments inhibited flowering completely in the first photophobe phase, inhibited flowering to only a small degree in the second photophobe phase, and inhibited flowering to an intermediate degree in the third photophobe phase. Far-red light interruptions strongly inhibited flowering in the first photophobe phase, especially when given early in the dark period. Three minutes of supplementary white light given at the twenty-fourth or forty-eighth hour of the cycle partially overcame the inhibitory effect of far-red light. Four hours of supplementary white light at these times completely overcame the far-red inhibition. PMID:16656688

  18. Importance of the Vadose Zone in Analyses of Unconfined Aquifer Tests

    USGS Publications Warehouse

    Moench, A.F.

    2004-01-01

    Analytical models commonly used to interpret unconfined aquifer tests have been based on upper-boundary (water table) conditions that do not adequately address effects of time-varying drainage from the vadose zone. As a result, measured and simulated drawdown data may not agree and hydraulic parameters may be inaccurately estimated. A 72-hour aquifer test conducted in Cape Cod, Massachusetts, in a slightly heterogeneous, coarse-grained, glacial outwash deposit was found to be a good candidate for testing models with different upper-boundary conditions. In general, under the commonly invoked assumption of instantaneous drainage, measured and simulated draw-downs were found to agree with one another only at late time and early time. In the intermediate-time range, because of delayed drainage, measured drawdowns always exceeded simulated values, most noticeably in piezometers located near the water table. To reduce these discrepancies, an analytical model was developed that can fully account for time-varying drainage given that the aquifer is not strongly heterogeneous. The approach is flexible as the model, which makes use of empirical relations, does not constrain drainage to follow any particular functional relation. By this approach, measured and simulated drawdowns agree over the complete time range, and the estimated parameters are consistent with prior studies and with what is known about the aquifer geometry, stratigraphy, and composition. By properly accounting for vadose zone drainage, it was found that realistic estimates of all hydraulic parameters, including specific yield, could be obtained with or without the use of late-time data.

  19. Selected aquifer-test information for the coastal plain aquifers of South Carolina

    USGS Publications Warehouse

    Aucott, W.R.; Newcome, Roy

    1986-01-01

    Aquifer and well hydraulic characteristics were determined from more than 100 multiple-well and single-well aquifer tests in the Coastal Plain of South Carolina and tabulated by county. Multiple-well aquifer tests were analyzed by the This method for nonleaky aquifers and the Hantush-Jacob method for leaky aquifers. Single-well tests were analyzed by straight line solution techniques for drawdown and recovery tests. Specific-capacity data are presented for many areas where aquifer-test information is sparse. The characteristics determined are based largely on well performance tests conducted by well drillers and consulting engineers. Although use of this information has many limitations, it has value in establishing transmissivity and storage coefficient values for the Coastal Plain aquifers. (Peters-PTT)

  20. Predictive Value of Total Serum Bilirubin within 6 Hour of Birth for the Development of Hyperbilirubinemia After 72 hours of Birth

    PubMed Central

    Vanaki, Raghavendra; Badakali, Ashok V.; Pol, Ramesh R; Yelamali, Bhuvaneshwari

    2016-01-01

    Introduction Neonatal jaundice is benign and no intervention might be required, but jaundice can be associated with an underlying disease condition, which therefore warrants accurate and unbiased estimation of bilirubin. Total Serum Bilirubin (TSB) measurements (at discharge between 18 hours and 72 hours) can be used to predict the chances of developing severe hyperbilirubinemia. Materials and Methods The present hospital-based prospective study was undertaken to determine the predictive value of serum bilirubin before 6 hours of life for subsequent hyperbilirubinemia in healthy term neonates. One hundred and fifty healthy term newborns delivered during January 2013–December 2013 at Hanagal Shri Kumareshwara Hospital and Research Centre, S. Nijalingappa Medical College, Bagalkot Karnataka, India, were included in the study. Serum bilirubin levels were estimated twice, first, within 6 hours of life and second, after 72 hours of life. Bilirubin values were plotted on previously published nomograms. Sensitivity, specificity of the test was established. Results A measure of TSB levels (within 6 hours of life) across the study population, showed that maximum number of infants (70/150) had TSB level between 4.1 and 5.5 mg/dL and 16 infants had TSB level >5.6 mg/dL. The TSB levels (after 72 hours of life) showed that maximum newborns (83/150) had TSB levels between 12.8 and 15.3 mg/dL and 9 infants had TSB levels between 7.7 and 10.2mg/dL. Eighteen infants developed hyperbilirubinemia. Newborns with TSB value of >4.95mg/dL within 6hours of life had developed significant hyperbilirubinemia after 72 hours of life with sensitivity of 100% and specificity of 89% (p=0.0001), which was highly statistically significant. Conclusion A TSB level of >5 mg/dL within 6 hours of birth would serve as a predictor for risk of subsequent hyperbilirubinemia in the near future. PMID:27790538

  1. Hydraulic tests in highly permeable aquifers

    USGS Publications Warehouse

    Butler, J.J.; Zhan, X.

    2004-01-01

    A semianalytical solution is presented for a mathematical model describing the flow of groundwater in response to a slug or pumping test in a highly permeable, confined aquifer. This solution, which is appropriate for wells of any degree of penetration and incorporates inertial mechanisms at both the test and observation wells, can be used to gain new insights into hydraulic tests in highly permeable settings. The oscillatory character of slug- and pumping-induced responses will vary considerably across a site, even in an essentially homogeneous formation, when wells of different radii, depths, and screen lengths are used. Thus variations in the oscillatory character of responses do not necessarily indicate variations in hydraulic conductivity (K). Existing models for slug tests in partially penetrating wells in high-K aquifers neglect the storage properties of the media. That assumption, however, appears reasonable for a wide range of common conditions. Unlike in less permeable formations, drawdown at an observation well in a high-K aquifer will be affected by head losses in the pumping well. Those losses, which affect the form of the pumping-induced oscillations, can be difficult to characterize. Thus analyses of observation-well drawdown should utilize data from the period after the oscillations have dissipated whenever possible. Although inertial mechanisms can have a large impact on early-time drawdown, that impact decreases rapidly with duration of pumping and distance to the observation well. Conventional methods that do not consider inertial mechanisms should therefore be viable options for the analysis of drawdown data at moderate to large times.

  2. Hydrologic Properties of Aquifers in the Central Savannah River Area

    SciTech Connect

    Snipes, D.S.; Benson, S.M.; Price Jr., Van; Temples, T.J.

    1996-01-02

    The hydrologic properties of selected aquifer systems underlying the Milhaven and Girard sites in Georgia were determined through a series of aquifer performance tests performed from October, 1994 to January, 1995. At the Milhaven site, the systems under investigation consisted of the upper, middle and lower components of the Upper Floridan, the lower Dublin, and the lower Midville aquifers. At the Dublin site, only the lower Dublin and lower Midville aquifers were tested. In addition, the hydrologic properties of the lower Midville aquifer underlying the P, B and D Areas at the Savannah River Site were determined by a series of aquifer tests conducted in 1993 and 1994. The tests generally consisted of collecting water level and atmospheric data for 24 hours followed by a 72 hour pump test and a subsequent 72 hour recovery period. These tests were designed to determine the aquifer properties over a large area, to determine whether any hydrologic boundaries existed in the area, and to find out if leakance could be induced through the confining units which separated the aquifer units.

  3. Solute changes during aquifer storage recovery testing in a limestone/clastic aquifer

    USGS Publications Warehouse

    Mirecki, J.E.; Campbell, B.G.; Conlon, K.J.; Petkewich, M.D.

    1998-01-01

    Aquifer storage recovery (ASR) was tested in the Santee Limestone/Black Mingo Aquifer near Charleston, South Carolina, to assess the feasibility for subsurface storage of treated drinking water. Water quality data obtained during two representative ASR tests were interpreted to show three things: (1) recovery efficiency of ASR in this geological setting; (2) possible changes in physical characteristics of the aquifer during ASR testing; and (3) water quality changes and potability of recovered water during short (one- and six-day) storage durations in the predominantly carbonate aquifer. Recovery efficiency for both ASR tests reported here was 54%. Successive ASR tests increased aquifer permeability of the Santee Limestone/Black Mingo Aquifer. It is likely that aquifer permeability increased during short storage periods due to dissolution of carbonate minerals and amorphous silica in aquifer material by treated drinking water. Dissolution resulted in an estimated 0.3% increase in pore volume of the permeable zones. Ground water composition generally evolved from a sodium-calcium bicarbonate water to a sodium chloride water during storage and recovery. After short duration, stored water can exceed the U.S. Environmental Protection Agency maximum contaminant level (MCL) for chloride (250 mg/L). However, sulfate, fluoride, and trihalomethane concentrations remained below MCLs during storage and recovery.Aquifer storage recovery (ASR) was tested in the Santee Limestone/Black Mingo Aquifer near Charleston, South Carolina, to assess the feasibility for subsurface storage of treated drinking water. Water quality data obtained during two representative ASR tests were interpreted to show three things: (1) recovery efficiency of ASR in this geological setting; (2) possible changes in physical characteristics of the aquifer during ASR testing; and (3) water quality changes and potability of recovered water during short (one- and six-day) storage durations in the predominantly

  4. Hydrogeology and water quality of the Floridan aquifer system and effect of Lower Floridan aquifer withdrawals on the Upper Floridan aquifer at Barbour Pointe Community, Chatham County, Georgia, 2013

    USGS Publications Warehouse

    Gonthier, Gerard J.; Clarke, John S.

    2016-06-02

    Two test wells were completed at the Barbour Pointe community in western Chatham County, near Savannah, Georgia, in 2013 to investigate the potential of using the Lower Floridan aquifer as a source of municipal water supply. One well was completed in the Lower Floridan aquifer at a depth of 1,080 feet (ft) below land surface; the other well was completed in the Upper Floridan aquifer at a depth of 440 ft below land surface. At the Barbour Pointe test site, the U.S. Geological Survey completed electromagnetic (EM) flowmeter surveys, collected and analyzed water samples from discrete depths, and completed a 72-hour aquifer test of the Floridan aquifer system withdrawing from the Lower Floridan aquifer.Based on drill cuttings, geophysical logs, and borehole EM flowmeter surveys collected at the Barbour Pointe test site, the Upper Floridan aquifer extends 369 to 567 ft below land surface, the middle semiconfining unit, separating the two aquifers, extends 567 to 714 ft below land surface, and the Lower Floridan aquifer extends 714 to 1,056 ft below land surface.A borehole EM flowmeter survey indicates that the Upper Floridan and Lower Floridan aquifers each contain four water-bearing zones. The EM flowmeter logs of the test hole open to the entire Floridan aquifer system indicated that the Upper Floridan aquifer contributed 91 percent of the total flow rate of 1,000 gallons per minute; the Lower Floridan aquifer contributed about 8 percent. Based on the transmissivity of the middle semiconfining unit and the Floridan aquifer system, the middle semiconfining unit probably contributed on the order of 1 percent of the total flow.Hydraulic properties of the Upper Floridan and Lower Floridan aquifers were estimated based on results of the EM flowmeter survey and a 72-hour aquifer test completed in Lower Floridan aquifer well 36Q398. The EM flowmeter data were analyzed using an AnalyzeHOLE-generated model to simulate upward borehole flow and determine the transmissivity of

  5. Estimation of hydraulic parameters from an unconfined aquifer test conducted in a glacial outwash deposit, Cape Cod, Massachusetts

    USGS Publications Warehouse

    Moench, A.F.; Garabedian, Stephen P.; LeBlanc, Denis R.

    2000-01-01

    An aquifer test conducted in a sand and gravel, glacial outwash deposit on Cape Cod, Massachusetts was analyzed by means of a model for flow to a partially penetrating well in a homogeneous, anisotropic unconfined aquifer. The model is designed to account for all significant mechanisms expected to influence drawdown in observation piezometers and in the pumped well. In addition to the usual fluid-flow and storage processes, additional processes include effects of storage in the pumped well, storage in observation piezometers, effects of skin at the pumped-well screen, and effects of drainage from the zone above the water table. The aquifer was pumped at a rate of 320 gallons per minute for 72-hours and drawdown measurements were made in the pumped well and in 20 piezometers located at various distances from the pumped well and depths below the land surface. To facilitate the analysis, an automatic parameter estimation algorithm was used to obtain relevant unconfined aquifer parameters, including the saturated thickness and a set of empirical parameters that relate to gradual drainage from the unsaturated zone. Drainage from the unsaturated zone is treated in this paper as a finite series of exponential terms, each of which contains one empirical parameter that is to be determined. It was necessary to account for effects of gradual drainage from the unsaturated zone to obtain satisfactory agreement between measured and simulated drawdown, particularly in piezometers located near the water table. The commonly used assumption of instantaneous drainage from the unsaturated zone gives rise to large discrepancies between measured and predicted drawdown in the intermediate-time range and can result in inaccurate estimates of aquifer parameters when automatic parameter estimation procedures are used. The values of the estimated hydraulic parameters are consistent with estimates from prior studies and from what is known about the aquifer at the site. Effects of

  6. Effect of a 72 Hour Stroke Care Bundle on Early Outcomes after Acute Stroke: A Non Randomised Controlled Study

    PubMed Central

    Nakibuuka, Jane; Sajatovic, Martha; Nankabirwa, Joaniter; Ssendikadiwa, Charles; Kalema, Nelson; Kwizera, Arthur; Byakika-Tusiime, Jayne; Furlan, Anthony J.; Kayima, James; Ddumba, Edward; Katabira, Elly

    2016-01-01

    Background Integrated care pathways (ICP) in stroke management are increasingly being implemented to improve outcomes of acute stroke patients. We evaluated the effect of implementing a 72 hour stroke care bundle on early outcomes among patients admitted within seven days post stroke to the national referral hospital in Uganda. Methods In a one year non-randomised controlled study, 127 stroke patients who had ‘usual care’ (control group) were compared to 127 stroke patients who received selected elements from an ICP (intervention group). Patients were consecutively enrolled (controls first, intervention group second) into each group over 5 month periods and followed to 30-days post stroke. Incidence outcomes (mortality and functional ability) were compared using chi square test and adjusted for potential confounders. Kaplan Meier survival estimates and log rank test for comparison were used for time to death analysis for all strokes and by stroke severity categories. Secondary outcomes were in-hospital mortality, median survival time and median length of hospital stay. Results Mortality within 7 days was higher in the intervention group compared to controls (RR 13.1, 95% CI 3.3–52.9). There was no difference in 30-day mortality between the two groups (RR 1.2, 95% CI 0.5–2.6). There was better 30-day survival in patients with severe stroke in the intervention group compared to controls (P = 0.018). The median survival time was 30 days (IQR 29–30 days) in the control group and 30 days (IQR 7–30 days) in the intervention group. In the intervention group, 41patients (32.3%) died in hospital compared to 23 (18.1%) in controls (P < 0.001). The median length of hospital stay was 8 days (IQR 5–12 days) in the controls and 4 days (IQR 2–7 days) in the intervention group. There was no difference in functional outcomes between the groups (RR 0.9, 95% CI 0.4–2.2). Conclusions While implementing elements of a stroke-focused ICP in a Ugandan national referral

  7. Effects of unsaturated zone on aquifer test analysis in a shallow-aquifer system

    USGS Publications Warehouse

    Halford, K.J.

    1997-01-01

    A comparison between two hypothetical flow models of an unconfined aquifer, one saturated and the other variably saturated, indicates that the variably saturated model which explicitly models drainage from the unsaturated zone provides a better conceptual framework for analyzing unconfined aquifer test data and better estimates of the lateral and vertical hydraulic conductivity in fine-grained sands. Explicitly accounting for multiple aquifers, well-bore storage, and the effects of delayed drainage from the unsaturated zone increases confidence in aquifer property estimates by removing some assumptions and allowing for the inclusion of early time data and water-table observations in an aquifer test analysis. The inclusion of the unsaturated zone expands the number of parameters to be estimated, but reasonable estimates of lateral and vertical hydraulic conductivity and specific storage of the unconfined aquifer can be obtained. For the cases examined, only the van Genuchten parameter ?? needed to be determined by the test, because the parameters n and ??(r) had a minimal effect on the estimates of hydraulic conductivities, and literature values could be used for these parameters. Estimates of lateral and vertical hydraulic conductivity using MODFLOW were not as good as the VS2DT based estimates and differed from the known values by as much as 30 percent. The hydraulic properties of a surficial aquifer system were estimated through a series of aquifer tests conducted at Cecil Field Naval Air Station in Jacksonville, Florida. Aquifer test results were analyzed by calibrating a variably saturated, radial flow model to the measured drawdowns. Parameter estimation was performed by minimizing the difference between simulated and measured drawdowns with an optimization routine coupled to VS2DT and was constrained by assuming that the hydraulic properties of each aquifer or confining unit were homogeneous. Given the hydrogeologic conditions at the field site, estimating

  8. Modeling cross-hole slug tests in an unconfined aquifer

    DOE PAGES

    Malama, Bwalya; Kuhlman, Kristopher L.; Brauchler, Ralf; Bayer, Peter

    2016-06-28

    Cross-hole slug test date are analyzed with an extended version of a recently published unconfined aquifer model accounting for waterable effects using the linearized kinematic condition. The use of cross-hole slug test data to characterize aquifer heterogeneity and source/observation well oscillation parameters is evaluated. The data were collected in a series of multi-well and multi-level pneumatic slug tests conducted at a site in Widen, Switzerland. Furthermore, the tests involved source and observation well pairs separated by distances of up to 4 m, and instrumented with pressure transducers to monitor aquifer response in discrete intervals.

  9. 18 CFR 806.12 - Constant-rate aquifer testing.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... withdraw or increase a withdrawal of groundwater shall perform a constant-rate aquifer test in accordance... groundwater availability analysis to determine the availability of water during a 1-in-10-year...

  10. 18 CFR 806.12 - Constant-rate aquifer testing.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... withdraw or increase a withdrawal of groundwater shall perform a constant-rate aquifer test in accordance... groundwater availability analysis to determine the availability of water during a 1-in-10-year...

  11. 18 CFR 806.12 - Constant-rate aquifer testing.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... withdraw or increase a withdrawal of groundwater shall perform a constant-rate aquifer test in accordance... groundwater availability analysis to determine the availability of water during a 1-in-10-year...

  12. 18 CFR 806.12 - Constant-rate aquifer testing.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... withdraw or increase a withdrawal of groundwater shall perform a constant-rate aquifer test in accordance... groundwater availability analysis to determine the availability of water during a 1-in-10-year...

  13. 18 CFR 806.12 - Constant-rate aquifer testing.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... withdraw or increase a withdrawal of groundwater shall perform a constant-rate aquifer test in accordance... groundwater availability analysis to determine the availability of water during a 1-in-10-year...

  14. Aquifer tests near the Idaho Falls Foothills, Idaho

    SciTech Connect

    Hubbell, J.M.

    1991-10-03

    Ground water pumping tests were performed in two wells located in the foothills east of Idaho Falls to determine the aquifer characteristics at these locations. These data were used to differentiate this aquifer from the Snake River Plain aquifer. The wells were pumped at rates of 11 and 14 gallons per minute with 0.03 and 0.04 ft of drawdown measured in the pumping wells. The transmissivity is estimated to be 525,000 gpd/ft and 450,000 gpd/ft, respectively. The hydraulic conductivity is 925 ft/day and 1,070 ft/day, respectively. These hydraulic conductivities are similar to those measured in the Snake River Plain aquifer. Water level data in these wells are consistent with the water table in the Snake River Plain aquifer and indicates ground water movement from the foothills toward the Plain. The high transmissivity suggests water may move rapidly from the foothills area to mix with water in the Snake River Plain aquifer. Elevated water temperatures (76 and 70{degrees}F) and high specific conductivities in these wells indicate the presence of a foothills aquifer with characteristics that can be used to separate the two aquifer systems.

  15. Antimotion-sickness efficacy of scopolamine 12 and 72 hours after transdermal administration

    NASA Technical Reports Server (NTRS)

    Graybiel, A.; Cramer, D. B.; Wood, C. D.

    1982-01-01

    The antimotion sickness remedy, transdermal therapeutic system-scopolamine, administered in this experiment was scheduled to deliver 1.0 mg of scopolamine over a period of 3 d, and this paper compares its efficacy 12 and 72 h after administration. In a double-blind study, six male college students were individually exposed to a standardized provocative test in a slow rotation room after six apparently identical treatments comprising four placebos and two medications. Efficacy was categorized as beneficial, inconsequential, or detrimental. None of the responses was detrimental. Following the first administration of the therapeutic system, there were four beneficial responses after 12 h but none was beneficial after 72 h. Following the second treatment regimen, there were four beneficial responses after 12 h and three beneficial responses after 72 h. Great individual differences were demonstrated, two subjects accounting for six beneficial responses and two accounting for only one beneficial response. The difference in efficacy after 12 and 72 h has practical and theoretical significance.

  16. A computer program (MACPUMP) for interactive aquifer-test analysis

    USGS Publications Warehouse

    Day-Lewis, F. D.; Person, M.A.; Konikow, L.F.

    1995-01-01

    This report introduces MACPUMP (Version 1.0), an aquifer-test-analysis package for use with Macintosh4 computers. The report outlines the input- data format, describes the solutions encoded in the program, explains the menu-items, and offers a tutorial illustrating the use of the program. The package reads list-directed aquifer-test data from a file, plots the data to the screen, generates and plots type curves for several different test conditions, and allows mouse-controlled curve matching. MACPUMP features pull-down menus, a simple text viewer for displaying data-files, and optional on-line help windows. This version includes the analytical solutions for nonleaky and leaky confined aquifers, using both type curves and straight-line methods, and for the analysis of single-well slug tests using type curves. An executable version of the code and sample input data sets are included on an accompanying floppy disk.

  17. Straddle-packer aquifer test analyses of the Snake River Plain aquifer at the Idaho National Engineering Laboratory

    SciTech Connect

    Johnson, G.S.; Frederick, D.B.

    1997-01-01

    The State of Idaho INEL Oversight Program, with the University of Idaho, Idaho State University, Boise State University, and the Idaho Geologic Survey, used a straddle-packer system to investigate vertical variations in characteristics of the Snake River Plain aquifer at the Idaho National Engineering Laboratory in southeast Idaho. Sixteen single-well aquifer tests were conducted on.isolated intervals in three observation wells. Each of these wells has approximately 200 feet of open borehole below the water table, penetrating the E through G and I basalt flow groups and interbedded sediments of the Snake River Plain aquifer. The success of the aquifer tests was limited by the inability to induce measurable drawdown in several zones. Time-drawdown data from aquifer tests were matched to type curves for 8 of the 16 zones tested. A single aquifer test at the water table exhibited greater curvature than those at depth. The increased degree of curvature suggests an unconfined response and resulted in an estimate of specific yield of 0.03. Aquifer tests below the water table generally yielded time-drawdown graphs with a rapid initial response followed by constant drawdown throughout the duration of the tests; up to several hours in length. The rapid initial response implies that the aquifer responds as a confined system during brief pumping periods. The nearly constant drawdown suggests a secondary source of water, probably vertical flow from overlying and underlying aquifer layers. Three analytical models were applied for comparison to the conceptual model and to provide estimates of aquifer properties. This, Hantush-Jacob leaky aquifer, and the Moench double-porosity fractured rock models were fit to time-drawdown data. The leaky aquifer type curves of Hantush and Jacob generally provided the best match to observed drawdown. A specific capacity regression equation was also used to estimate hydraulic conductivity.

  18. Aquifer test plan for the 100-HR-3 Operable Unit

    SciTech Connect

    Swanson, L.C.; Hartman, M.J.

    1994-03-28

    This test plan directs hydrologic testing activities planned at three existing Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) wells in the 100-HR-3 Operable Unit of the Hanford Site. Three additional wells will be installed near these existing wells and used as additional testing arid observation points during the field activities. Figure 1 shows the locations of the three test sites. A primary objective of the testing program is to provide more detailed hydraulic characterization information for the unconfined aquifer and targeted test sites than provided by the initial reconnaissance-level slug testing of Vukelich. A second objective is to evaluate the applicability of slug interference and dipole flow tests for detailed hydraulic characterization in an unconfined aquifer. This aquifer testing program will also be useful for substantiating hydraulic conductivities reported from previous slug tests and evaluating the effects of filter pack volume/configuration on slug test data. Vukelich recommended additional testing to address the latter two issues.

  19. Unplanned reattendances at the paediatric emergency department within 72 hours: a one-year experience in KKH

    PubMed Central

    Goh, Guan Lin; Huang, Peiqi; Kong, Man Ching Patrick; Chew, So-Phia; Ganapathy, Sashikumar

    2016-01-01

    INTRODUCTION Unscheduled reattendances at the paediatric emergency department may contribute to overcrowding, which may increase financial burdens. The objectives of this study were to determine the rate of reattendances and characterise factors influencing these reattendances and hospital admission during the return visits. METHODS Medical records of all patients who attended the emergency department at KK Women’s and Children’s Hospital, Singapore, from 1 June 2013 to 31 May 2014 were retrospectively reviewed. We collected data on patient demographics, attendance data and clinical characteristics. Planned reattendances, recalled cases, reattendances for unrelated complaints and patients who left without being seen were excluded. A multivariate analysis was conducted to determine the odds ratio of variables associated with hospital admission for reattendances. RESULTS Of 162,566 children, 6,968 (4.3%) returned within 72 hours, and 2,925 (42.0% of reattendance group) were admitted on their return visits. Children more likely to reattend were under three years of age, Chinese, triaged as Priority 2 at the first visit, and were initially diagnosed with respiratory or gastrointestinal conditions. However, children more likely to be admitted on their return visits were over 12 years of age, Malay, had a higher triage acuity or were uptriaged, had the presence of a comorbidity, and were diagnosed with gastrointestinal conditions. CONCLUSION We identified certain subgroups in the population who were more likely to be admitted if they reattended. These findings would help in implementing further research and directing strategies to reduce potentially avoidable reattendances and admissions. PMID:27353384

  20. The dipole flow test: A new single-borehole test for aquifer characterization

    SciTech Connect

    Kabala, Z.J. )

    1993-01-01

    A new single-borehole measurement technique for confined aquifers, the dipole flow test, yields the vertical distributions of the horizontal hydraulic conductivity, the vertical hydraulic conductivity, and the specific storativity when applied to different borehole intervals. The test utilizes straddle packers to isolate two chambers in the borehole, pressure transducers to monitor drawdown in them, and a small pump to create a dipole flow pattern in the aquifer by pumping water at a constant rate from the aquifer into one chamber, transferring it within the well to the next chamber, and finally injecting it back to the aquifer. A mathematical model describing the drawdown in each chamber is derived for the transient as well as the steady state cases. The aquifer parameters may be estimated from data produced by the dipole flow test alone or in conjunction with conventional pumping tests. The dipole flow regime reaches a steady state relatively quickly, especially in well permeable aquifers. A robust computational methodology for estimating the aquifer parameters, suitable for automatization, is based on the Newton-Raphson algorithm applied to a system of up to three nonlinear equations, each describing the well drawdown at a different judiciously chosen time. Due to the relatively small drawdown it invokes, the dipole flow test may be applicable to unconfined aquifers as well.

  1. Investigating groundwater arsenic contamination using aquifer push-pull test

    NASA Astrophysics Data System (ADS)

    Daigle, A. R.; Jin, Q.

    2009-12-01

    The groundwater of the Southern Willamette Basin, OR is contaminated with arsenic at concentrations as high as several ppm. A single-well push-pull test was conducted to investigate how microbial metabolisms control arsenic occurrence and levels in the bedrock aquifer of the area. During the experiments, a test solution containing ethanol was first injected into the aquifer. As the experiment progressed, dissolved gasses, groundwater, and sediment were sampled to monitor the variations in the chemical parameters, including the speciation of iron, sulfur, and arsenic, in the aquifer. Ethanol amendment stimulated a series of microbial metabolisms, including arsenate reduction, iron reduction, and sulfate reduction. Iron reduction released arsenic sorbed onto the aquifer sediments, increasing groundwater arsenic levels. Arsenate reduction converted arsenate to arsenite and, as a result, most arsenic occurred as arsenite in the groundwater. Results of the experiments demonstrate how different microbial functional groups influenced arsenic contamination in the area. These results also shed new light on potential bioremediation strategies in the area.

  2. Characterizing a faulted aquifer by field testing and numerical simulation.

    PubMed

    Allen, D M; Michel, F A

    1999-01-01

    Faulted aquifers constitute one of the most complex geological environments for analysis and interpretation of hydraulic test data because of the inherent ability of faults to act not only as highly transmissive zones but also as hydraulic barriers. Previous studies of the fractured carbonate aquifer at Carleton University, Ottawa, Canada, characterized the flow regime as predominantly linear, but with limited radial nature, and undertook to analyze constant discharge test data using both radial and linear flow models. When used as direct input to a numerical model, the hydraulic parameters, calculated directly from hydraulic test data, were inappropriate and resulted in a poorly calibrated model. While our interpretation of the faulted aquifer remains linear-radial in nature, parameter estimation by numerical simulation highlighted the presence of hydraulic barriers associated with the faults. These barriers are not readily apparent in the constant discharge test data and act to modify the hydraulic test curves at early to mid time, leading to incorrect estimates of the hydraulic parameters. This paper describes the conceptual model and the numerical approach, and demonstrates the importance of using transient simulations for model calibration. PMID:19125925

  3. Slug test in an unconfined aquifer: A Richards` equation perspective

    SciTech Connect

    Weeber, P.; Narasimhan, T.N.

    1997-10-01

    Slug tests have been used for over 30 years as a means of evaluating hydraulic parameters of aquifers. The interpretation of transient water level data from these tests has almost exclusively been based on fitting the data to analytical solutions or on using semi-analytical methods. Because these methods are constrained by simplifying assumptions, it is useful to investigate the conditions under which these assumptions are reasonable so that the interpretation of field data can be carried out with increased confidence. To this end, the authors investigate the transient flow of water in an unconfined aquifer during a slug test, using a numerical model that solves the generalized Richards` equation. The model accounts for saturated-unsaturated flow, time-dependent seepage face in the well, various combinations of blank casings and well screens, and injection or withdrawal tests. Parametric studies were conducted using a fully penetrating well in a 10 meter thick, homogeneous, isotropic aquifer with an initial hydrostatic condition in order to provide insights into such issues as (1) the difference in response between injection and bail-out tests, (2) the significance of flow through the transient seepage face, and (3) the role of the unsaturated zone. An examination of the flow anatomy suggests that flow in the unsaturated zone is significant and important, although the response of the water level in the well may not be very sensitive to the unsaturated zone processes. A second part of the present study investigated the reasonableness of widely used techniques of interpretation.

  4. Summary of Aquifer Test Data for Arkansas - 1940-2006

    USGS Publications Warehouse

    Pugh, Aaron L.

    2008-01-01

    As demands on Arkansas's ground water continue to increase, decision-makers need all available information to ensure the sustainability of this important natural resource. From 1940 through 2006, the U.S. Geological Survey has conducted over 300 aquifer tests in Arkansas. Much of these data never have been published. This report presents the results from 206 of these aquifer tests from 21 different hydrogeologic units spread across 51 Arkansas counties. Ten of the hydrogeologic units are within the Atlantic Plain of Arkansas and consist mostly of unconsolidated and semi-consolidated deposits. The remaining 11 units are within the Interior Highlands consisting mainly of consolidated rock. Descriptive statistics are reported for each hydrologic unit with two or more tests, including the mean, minimum, median, maximum and standard deviation values for specific capacity, transmissivity, hydraulic conductivity, and storage coefficient. Hydraulic conductivity values for the major water-bearing hydrogeologic units are estimated because few conductivity values are recorded in the original records. Nearly all estimated hydraulic conductivity values agree with published hydraulic conductivity values based on the hydrogeologic unit material types. Similarly, because few specific capacity values were available in the original aquifer test records, specific capacity values are estimated for individual wells.

  5. Arsenic control during aquifer storage recovery cycle tests in the Floridan Aquifer.

    PubMed

    Mirecki, June E; Bennett, Michael W; López-Baláez, Marie C

    2013-01-01

    Implementation of aquifer storage recovery (ASR) for water resource management in Florida is impeded by arsenic mobilization. Arsenic, released by pyrite oxidation during the recharge phase, sometimes results in groundwater concentrations that exceed the 10 µg/L criterion defined in the Safe Drinking Water Act. ASR was proposed as a major storage component for the Comprehensive Everglades Restoration Plan (CERP), in which excess surface water is stored during the wet season, and then distributed during the dry season for ecosystem restoration. To evaluate ASR system performance for CERP goals, three cycle tests were conducted, with extensive water-quality monitoring in the Upper Floridan Aquifer (UFA) at the Kissimmee River ASR (KRASR) pilot system. During each cycle test, redox evolution from sub-oxic to sulfate-reducing conditions occurs in the UFA storage zone, as indicated by decreasing Fe(2+) /H2 S mass ratios. Arsenic, released by pyrite oxidation during recharge, is sequestered during storage and recovery by co-precipitation with iron sulfide. Mineral saturation indices indicate that amorphous iron oxide (a sorption surface for arsenic) is stable only during oxic and sub-oxic conditions of the recharge phase, but iron sulfide (which co-precipitates arsenic) is stable during the sulfate-reducing conditions of the storage and recovery phases. Resultant arsenic concentrations in recovered water are below the 10 µg/L regulatory criterion during cycle tests 2 and 3. The arsenic sequestration process is appropriate for other ASR systems that recharge treated surface water into a sulfate-reducing aquifer.

  6. Arsenic control during aquifer storage recovery cycle tests in the Floridan Aquifer.

    PubMed

    Mirecki, June E; Bennett, Michael W; López-Baláez, Marie C

    2013-01-01

    Implementation of aquifer storage recovery (ASR) for water resource management in Florida is impeded by arsenic mobilization. Arsenic, released by pyrite oxidation during the recharge phase, sometimes results in groundwater concentrations that exceed the 10 µg/L criterion defined in the Safe Drinking Water Act. ASR was proposed as a major storage component for the Comprehensive Everglades Restoration Plan (CERP), in which excess surface water is stored during the wet season, and then distributed during the dry season for ecosystem restoration. To evaluate ASR system performance for CERP goals, three cycle tests were conducted, with extensive water-quality monitoring in the Upper Floridan Aquifer (UFA) at the Kissimmee River ASR (KRASR) pilot system. During each cycle test, redox evolution from sub-oxic to sulfate-reducing conditions occurs in the UFA storage zone, as indicated by decreasing Fe(2+) /H2 S mass ratios. Arsenic, released by pyrite oxidation during recharge, is sequestered during storage and recovery by co-precipitation with iron sulfide. Mineral saturation indices indicate that amorphous iron oxide (a sorption surface for arsenic) is stable only during oxic and sub-oxic conditions of the recharge phase, but iron sulfide (which co-precipitates arsenic) is stable during the sulfate-reducing conditions of the storage and recovery phases. Resultant arsenic concentrations in recovered water are below the 10 µg/L regulatory criterion during cycle tests 2 and 3. The arsenic sequestration process is appropriate for other ASR systems that recharge treated surface water into a sulfate-reducing aquifer. PMID:23106789

  7. Virtual Drawdown Tests of Groundwater Aquifers from Insar Remote Sensing

    NASA Astrophysics Data System (ADS)

    Zebker, H. A.; Chen, J.; Smith, R.

    2015-12-01

    Groundwater management depends on the type and quality of field data available describing a given aquifer system. Our increasing reliance on groundwater, especially as traditional surface supplies continue to be overexploited due to rising population and standard of living, requires that we better understand the state of our subsurface supplies. Groundwater aquifers, and the water flow models that relate aquifer parameters to management strategies, are typically characterized in terms of how much water is available at any point in the basin (storativity), and how easily water can flow from one point to another (transmissivity). Often these parameters are estimated by field drawdown tests, in which a known quantity of water is withdrawn from the aquifer, and the resulting spatial and temporal distribution of hydraulic head analyzed. Pumping tests can be expensive and time consuming, so that for most aquifer systems very few drawdown test data sets exist. Here we show that estimates for storativity and hydraulic conductance can be derived from time series InSAR observations coupled with well head measurements. While this requires the presence of monitoring wells in the basin, monitor-only wells are often fairly plentiful. Comparison of hydraulic head and InSAR deformation data at a monitoring well yields the ratio of head to subsidence and any time delay between the two, from which we solve for the needed conductivity and storativity. We present examples of these parameters associated with groundwater systems in the San Luis Valley, CO, and the Central Valley area of California, as observed by several spaceborne radar systems and validated by comparison with field data. The fundamental relation between pressure and stress resulting in changes in hydraulic head yields a simple linear relationship between deformation Δb, hydraulic head Δh, and skeletal storage coefficient: Sk = Δb / Δh, so that measuring deformation everywhere above an aquifer over time yields

  8. Fracture trace map and single-well aquifer test results in a carbonate aquifer in Berkeley County, West Virginia

    USGS Publications Warehouse

    McCoy, Kurt J.; Podwysocki, Melvin H.; Crider, E. Allen; Weary, David J.

    2005-01-01

    These data contain information on the results of single-well aquifer tests, lineament analysis, and a bedrock geologic map compilation for the low-lying carbonate and shale areas of eastern Berkeley County, West Virginia. Efforts have been initiated by management agencies of Berkeley County in cooperation with the U.S. Geological Survey to further the understanding of the spatial distribution of fractures in the carbonate regions and their correlation with aquifer properties. This report presents transmissivity values from about 200 single-well aquifer tests and a map of fracture-traces determined from aerial photos and field investigations. Transmissivity values were compared to geologic factors possibly affecting its magnitude.

  9. Aquifer Tests and Characterization of Transmissivity, Ada-Vamoosa Aquifer on the Osage Reservation, Osage County, Oklahoma, 2006

    USGS Publications Warehouse

    Abbott, Marvin M.; DeHay, Kelli

    2008-01-01

    The Ada-Vamoosa aquifer of northeastern Oklahoma is a sedimentary bedrock aquifer of Pennsylvanian age that crops out over 800 square miles of the Osage Reservation. The Osage Nation needed additional information regarding the production potential of the aquifer to aid them in future development planning. To address this need, the U.S. Geological Survey, in cooperation with the Osage Nation, conducted a study of aquifer properties in the Ada-Vamoosa aquifer. This report presents the results of the aquifer tests from 20 wells in the Ada-Vamoosa aquifer and one well in a minor aquifer east of the Ada-Vamoosa outcrop on the Osage Reservation. Well information for 17 of the 21 wells in this report was obtained from the Indian Health Service. Data collected by the U.S. Geological Survey during this investigation are pumping well data from four domestic wells collected during the summer of 2006. Transmissivity values were calculated from well pumping data or were estimated from specific capacity values depending on the reliability of the data. The estimated transmissivity values are 1.1 to 4.3 times greater than the calculated transmissivity values. The calculated and estimated transmissivity values range from 5 to 1,000 feet squared per day.

  10. Modeling cross-hole slug tests in an unconfined aquifer

    NASA Astrophysics Data System (ADS)

    Malama, Bwalya; Kuhlman, Kristopher L.; Brauchler, Ralf; Bayer, Peter

    2016-09-01

    A modified version of a published slug test model for unconfined aquifers is applied to cross-hole slug test data collected in field tests conducted at the Widen site in Switzerland. The model accounts for water-table effects using the linearized kinematic condition. The model also accounts for inertial effects in source and observation wells. The primary objective of this work is to demonstrate applicability of this semi-analytical model to multi-well and multi-level pneumatic slug tests. The pneumatic perturbation was applied at discrete intervals in a source well and monitored at discrete vertical intervals in observation wells. The source and observation well pairs were separated by distances of up to 4 m. The analysis yielded vertical profiles of hydraulic conductivity, specific storage, and specific yield at observation well locations. The hydraulic parameter estimates are compared to results from prior pumping and single-well slug tests conducted at the site, as well as to estimates from particle size analyses of sediment collected from boreholes during well installation. The results are in general agreement with results from prior tests and are indicative of a sand and gravel aquifer. Sensitivity analysis show that model identification of specific yield is strongest at late-time. However, the usefulness of late-time data is limited due to the low signal-to-noise ratios.

  11. Hydraulic characterization of aquifers by thermal response testing

    NASA Astrophysics Data System (ADS)

    Wagner, Valentin; Blum, Philipp; Bayer, Peter

    2014-05-01

    Temperature as a major physical quantity of the subsurface, and naturally occurring thermal anomalies are recognized as promising passive tracers to characterize the subsurface. Accelerated by the increasing popularity of geothermal energy, also active thermal field experiments have gained interest in hydrogeology. Such experiments involve artificial local ground heating or cooling. Among these, the thermal response test (TRT) is one of the most established field investigation techniques in shallow geothermal applications. It is a common method to investigate important subsurface heat transport parameters to design sustainable ground-source heat pump (GSHP) systems. During the test, the borehole heat exchanger (BHE) is heated up with a defined amount of energy by circulating a heat carrier fluid. By comparing temperature change between BHE inlet and outlet, the ability of the BHE to transfer heat or cold to the ambient ground is assessed. However, standard interpretation does not provide any insight into the governing processes of in-situ heat transfer. We utilize a groundwater advection sensitive TRT evaluation approach based on the analytical moving line source equation. It is shown that the TRT as a classical geothermal field test can also be used as a hydrogeological field test. Our approach benefits from the fact that thermal properties, such as thermal conductivity, of natural aquifers typically are much less variable than hydraulic properties, such as hydraulic conductivity. It is possible to determine a relatively small hydraulic conductivity range with our TRT evaluation approach, given realistic ranges for thermal conductivity, volumetric heat capacity, thermal dispersivity and thermal borehole resistance. The method is successfully tested on a large-scale geothermal laboratory experiment (9 m × 6 m × 4.5 m) and with a commercially performed TRT in the field scale. The laboratory experiment consists of a layered artificial aquifer, which is penetrated

  12. Estimating hydraulic properties of volcanic aquifers using constant-rate and variable-rate aquifer tests

    USGS Publications Warehouse

    Rotzoll, K.; El-Kadi, A. I.; Gingerich, S.B.

    2007-01-01

    In recent years the ground-water demand of the population of the island of Maui, Hawaii, has significantly increased. To ensure prudent management of the ground-water resources, an improved understanding of ground-water flow systems is needed. At present, large-scale estimations of aquifer properties are lacking for Maui. Seven analytical methods using constant-rate and variable-rate withdrawals for single wells provide an estimate of hydraulic conductivity and transmissivity for 103 wells in central Maui. Methods based on constant-rate tests, although not widely used on Maui, offer reasonable estimates. Step-drawdown tests, which are more abundantly used than other tests, provide similar estimates as constant-rate tests. A numerical model validates the suitability of analytical solutions for step-drawdown tests and additionally provides an estimate of storage parameters. The results show that hydraulic conductivity is log-normally distributed and that for dike-free volcanic rocks it ranges over several orders of magnitude from 1 to 2,500 m/d. The arithmetic mean, geometric mean, and median values of hydraulic conductivity are respectively 520, 280, and 370 m/d for basalt and 80, 50, and 30 m/d for sediment. A geostatistical approach using ordinary kriging yields a prediction of hydraulic conductivity on a larger scale. Overall, the results are in agreement with values published for other Hawaiian islands. ?? 2007 American Water Resources Association.

  13. Field testing the hypothesis of Darcian flow through a carbonate aquifer.

    USGS Publications Warehouse

    Hickey, J.J.

    1984-01-01

    The acceptability of the hypothesis of Darcian flow through a semiconfined carbonate aquifer was tested prior to running a multiple-day aquifer test in Pinellas County, Florida. The approach used to test the hypothesis was to run a number of hour-long aquifer tests at different discharges with drawdown measured at the same time during each test in two observation wells, one at 35 feet and the other at 733 feet from the pumped well. The hypothesis of Darcian flow through the semiconfined carbonate aquifer was deemed acceptable.-from Author

  14. Applicability of slug interference tests for hydraulic characterization of unconfined aquifers. 2: Field test examples

    SciTech Connect

    Spane, F.A. Jr.; Thorne, P.D.; Swanson, L.C.

    1996-09-01

    Slug interference testing may be particularly useful for characterizing hydraulic properties of aquifer sites where disposal of contaminated ground water makes pumping tests undesirable. The design, performance, and analysis of slug interference tests for two field test examples are presented. Results were compared with standard constant-rate pumping tests. The comparison indicates that slug interference tests provide estimates comparable to those obtained from short duration pumping tests for the determination of transmissivity, storativity, and vertical anisotropy. The close agreement in hydraulic property values obtained using the two test methods suggests that slug interference testing, under favorable test conditions (for example, observation well distances {le}30 m), can provide representative aquifer characterization results. The quality and extent of test data obtained also indicate the potential use of slug interference testing for three-dimensional hydrologic characterization investigations, when conducted using multilevel monitoring facilities.

  15. Applicability of slug interference tests for hydraulic characterization of unconfined aquifers: (1) analytical assessment

    SciTech Connect

    Spane, F.A.

    1996-01-01

    Aquifer test methods available for characterizing hazardous waste sites are sometimes restricted because of problems with disposal of contaminated ground water. Partly for this reason, slug tests have become a popular method for determining hydraulic properties at such sites. Slug interference responses within unconfined aquifers are characterized by an initial wave or hump, which is followed by a flat transitional plateau region and then by a declining, recessional limb segment. The shape and amplitude of the initial wave are primarily controlled by the elastic characteristics (i.e., S) and degree of anisotropy within the aquifer, while transmissivity is the principal parameter affecting the transmission (i.e., arrival time) of the slug interference response. Wellbore storage and delayed-yield effects tend to attenuate the test response. The transitional and late-time recessional segments are significantly influenced by the aquifer`s specific yield. In addition, test well/aquifer relationships, e.g., observation well distance, aquifer thickness, and well depth/aquifer penetration, also strongly affect slug interference characteristics. The sensitivity of the propagated response to test well/aquifer relationships indicates that slug interference tests can be designed to maximize the expected response for aquifer property characterization.

  16. Documentation of spreadsheets for the analysis of aquifer-test and slug-test data

    USGS Publications Warehouse

    Halford, Keith J.; Kuniansky, Eve L.

    2002-01-01

    Several spreadsheets have been developed for the analysis of aquifer-test and slug-test data. Each spreadsheet incorporates analytical solution(s) of the partial differential equation for ground-water flow to a well for a specific type of condition or aquifer. The derivations of the analytical solutions were previously published. Thus, this report abbreviates the theoretical discussion, but includes practical information about each method and the important assumptions for the applications of each method. These spreadsheets were written in Microsoft Excel 9.0 (use of trade names does not constitute endorsement by the USGS). Storage properties should not be estimated with many of the spreadsheets because most are for analyzing single-well tests. Estimation of storage properties from single-well tests is generally discouraged because single-well tests are affected by wellbore storage and by well construction. These non-ideal effects frequently cause estimates of storage to be erroneous by orders of magnitude. Additionally, single-well tests are not sensitive to aquifer-storage properties. Single-well tests include all slug tests (Bouwer and Rice Method, Cooper, Bredehoeft, Papadopulos Method, and van der Kamp Method), the Cooper-Jacob straight-line Method, Theis recovery-data analysis, Jacob-Lohman method for flowing wells in a confined aquifer, and the step-drawdown test. Multi-well test spreadsheets included in this report are; Hantush-Jacob Leaky Aquifer Method and Distance-Drawdown Methods. The distance-drawdown method is an equilibrium or steady-state method, thus storage cannot be estimated.

  17. Effects of Barometric Fluctuations on Well Water-Level Measurements and Aquifer Test Data

    SciTech Connect

    Spane, Frank A.

    1999-12-16

    This report examines the effects of barometric fluctuations on well water-level measurements and evaluates adjustment and removal methods for determining areal aquifer head conditions and aquifer test analysis. Two examples of Hanford Site unconfined aquifer tests are examined that demonstrate baro-metric response analysis and illustrate the predictive/removal capabilities of various methods for well water-level and aquifer total head values. Good predictive/removal characteristics were demonstrated with best corrective results provided by multiple-regression deconvolution methods.

  18. Pumping tests in nonuniform aquifers - The radially symmetric case

    USGS Publications Warehouse

    Butler, J.J.

    1988-01-01

    Traditionally, pumping-test-analysis methodology has been limited to applications involving aquifers whose properties are assumed uniform in space. This work attempts to assess the applicability of analytical methodology to a broader class of units with spatially varying properties. An examination of flow behavior in a simple configuration consisting of pumping from the center of a circular disk embedded in a matrix of differing properties is the basis for this investigation. A solution describing flow in this configuration is obtained through Laplace-transform techniques using analytical and numerical inversion schemes. Approaches for the calculation of flow properties in conditions that can be roughly represented by this simple configuration are proposed. Possible applications include a wide variety of geologic structures, as well as the case of a well skin resulting from drilling or development. Of more importance than the specifics of these techniques for analysis of water-level responses is the insight into flow behavior during a pumping test that is provided by the large-time form of the derived solution. The solution reveals that drawdown during a pumping test can be considered to consist of two components that are dependent and independent of near-well properties, respectively. Such an interpretation of pumping-test drawdown allows some general conclusions to be drawn concerning the relationship between parameters calculated using analytical approaches based on curve-matching and those calculated using approaches based on the slope of a semilog straight line plot. The infinite-series truncation that underlies the semilog analytical approaches is shown to remove further contributions of near-well material to total drawdown. In addition, the semilog distance-drawdown approach is shown to yield an expression that is equivalent to the Thiem equation. These results allow some general recommendations to be made concerning observation-well placement for pumping

  19. Hydrologeology and water quality of the Floridan aquifer system and effect of Lower Floridan aquifer pumping on the Upper Floridan aquifer, Pooler, Chatham County, Georgia, 2011–2012

    USGS Publications Warehouse

    Gonthier, Gerard J.

    2012-01-01

    ), respectively. Horizontal hydraulic conductivity of 4 ft/d for the Lower Floridan confining unit, derived from aquifer-test analyses, is near the midrange for values derived from packer-isolated slug tests. The transmissivity of the entire Floridan aquifer system derived from aquifer-test analyses totals about 51,000 ft2/d, similar to the value of 58,000 ft2/d derived from open slug tests on the entire Floridan aquifer system. Water-level data for each aquifer test were filtered for external influences such as barometric pressure, earth-tide effects, and long-term trends to enable detection of small (less than 1 foot) water-level responses to aquifer-test pumping. During the 72-hour aquifer test of pumping the Lower Floridan aquifer, a drawdown response of 51.7 ft was observed in the Lower Floridan pumped well and a drawdown response of 0.9 foot was observed in the Upper Floridan observation well located 85 ft from the pumped well.

  20. Tritium tracer test to estimate aquifer recharge under irrigated conditions

    NASA Astrophysics Data System (ADS)

    Jimenez-Martinez, J.; Tamoh, K.; Candela, L.

    2009-12-01

    Environmental tracers, as tritium, have been generally used to estimate aquifer recharge under natural conditions. A tritium tracer test to estimate recharge under semi-arid and irrigated conditions is presented. The test was carried out in an experimental plot under drip irrigation, located in SE Spain, with annual row crops (rotation lettuce and melon), following common agricultural practices in open air. Tritiated water was applied as an irrigation pulse, soil cores were taken at different depths and a liquid scintillation analyzer was used to measure the concentration of tritium in soil samples. Transport of tritium was simulated with SOLVEG code, a one-dimensional numerical model for simulating transport of heat, water and tritiated water in liquid and gas phase, which has been modified and adapted for this experience, including ground cover, root growth and root water uptake. One crop has been used to calibrate the modeling approach and other three crops to validate it. Results of flow and transport modelling show a good agreement between observed and estimated tritium concentration profile. For the period October 2007-September 2008, total drainage obtained value was 441 mm.

  1. WTAQ - A computer program for aquifer-test analysis of confined and unconfined aquifers

    USGS Publications Warehouse

    Barlow, P.M.; Moench, A.F.

    2004-01-01

    Computer program WTAQ was developed to implement a Laplace-transform analytical solution for axial-symmetric flow to a partially penetrating, finite-diameter well in a homogeneous and anisotropic unconfined (water-table) aquifer. The solution accounts for wellbore storage and skin effects at the pumped well, delayed response at an observation well, and delayed or instantaneous drainage from the unsaturated zone. For the particular case of zero drainage from the unsaturated zone, the solution simplifies to that of axial-symmetric flow in a confined aquifer. WTAQ calculates theoretical time-drawdown curves for the pumped well and observation wells and piezometers. The theoretical curves are used with measured time-drawdown data to estimate hydraulic parameters of confined or unconfined aquifers by graphical type-curve methods or by automatic parameter-estimation methods. Parameters that can be estimated are horizontal and vertical hydraulic conductivity, specific storage, and specific yield. A sample application illustrates use of WTAQ for estimating hydraulic parameters of a hypothetical, unconfined aquifer by type-curve methods. Copyright ASCE 2004.

  2. Evaluation of longitudinal dispersivity estimates from forced-gradient tracer tests in heterogeneous aquifers

    USGS Publications Warehouse

    Tiedeman, C.R.; Hsieh, P.A.

    2002-01-01

    Converging radial-flow and two-well tracer tests are simulated in two-dimensional aquifers to investigate the effects of heterogeneity and forced-gradient test configuration on longitudinal dispersivity (??L) estimates, and to compare ??L estimates from forced-gradient tests with ??L values that characterize solute spreading under natural-gradient flow. Results indicate that in both mildly and highly heterogeneous aquifers, ??L estimates from two-well tests are generally larger than those from radial-flow tests. In mildly heterogeneous aquifers, ??L estimates from two-well tests with relatively large tracer transport distances are similar to ??L values from natural-gradient simulations. In highly heterogeneous aquifers, ??L estimates from two-well tests at all tracer transport distances are typically smaller than ??L values from natural-gradient simulations.

  3. Estimating hydraulic properties using a moving-model approach and multiple aquifer tests

    USGS Publications Warehouse

    Halford, K.J.; Yobbi, D.

    2006-01-01

    A new method was developed for characterizing geohydrologic columns that extended >600 m deep at sites with as many as six discrete aquifers. This method was applied at 12 sites within the Southwest Florida Water Management District. Sites typically were equipped with multiple production wells, one for each aquifer and one or more observation wells per aquifer. The average hydraulic properties of the aquifers and confining units within radii of 30 to >300 m were characterized at each site. Aquifers were pumped individually and water levels were monitored in stressed and adjacent aquifers during each pumping event. Drawdowns at a site were interpreted using a radial numerical model that extended from land surface to the base of the geohydrologic column and simulated all pumping events. Conceptually, the radial model moves between stress periods and recenters on the production well during each test. Hydraulic conductivity was assumed homogeneous and isotropic within each aquifer and confining unit. Hydraulic property estimates for all of the aquifers and confining units were consistent and reasonable because results from multiple aquifers and pumping events were analyzed simultaneously. Copyright ?? 2005 National Ground Water Association.

  4. Interpretation of transmissivity estimates from single-well pumping aquifer tests

    USGS Publications Warehouse

    Halford, K.J.; Weight, W.D.; Schreiber, R.P.

    2006-01-01

    Interpretation of single-well tests with the Cooper-Jacob method remains more reasonable than most alternatives. Drawdowns from 628 simulated single-well tests where transmissivity was specified were interpreted with the Cooper-Jacob straight-line method to estimate transmissivity. Error and bias as a function of vertical anisotropy, partial penetration, specific yield, and interpretive technique were investigated for transmissivities that ranged from 10 to 10,000 m2/d. Cooper-Jacob transmissivity estimates in confined aquifers were affected minimally by partial penetration, vertical anisotropy, or analyst. Cooper-Jacob transmissivity estimates of simulated unconfined aquifers averaged twice the known values. Transmissivity estimates of unconfined aquifers were not improved by interpreting results with an unconfined aquifer solution. Judicious interpretation of late-time data consistently improved estimates where transmissivity exceeded 250 m2/d in unconfined aquifers. ?? 2006 National Ground Water Association.

  5. The University of Minnesota aquifer thermal energy storage (ATES) field test facility -- system description, aquifer characterization, and results of short-term test cycles

    SciTech Connect

    Walton, M.; Hoyer, M.C.; Eisenreich, S.J.; Holm, N.L.; Holm, T.R.; Kanivetsky, R.; Jirsa, M.A.; Lee, H.C.; Lauer, J.L.; Miller, R.T.; Norton, J.L.; Runke, H. )

    1991-06-01

    Phase 1 of the Aquifer Thermal Energy Storage (ATES) Project at the University of Minnesota was to test the feasibility, and model, the ATES concept at temperatures above 100{degrees}C using a confined aquifer for the storage and recovery of hot water. Phase 1 included design, construction, and operation of a 5-MW thermal input/output field test facility (FTF) for four short-term ATES cycles (8 days each of heat injection, storage, and heat recover). Phase 1 was conducted from May 1980 to December 1983. This report describes the FTF, the Franconia-Ironton-Galesville (FIG) aquifer used for the test, and the four short-term ATES cycles. Heat recovery; operational experience; and thermal, chemical, hydrologic, and geologic effects are all included. The FTF consists of monitoring wells and the source and storage well doublet completed in the FIG aquifer with heat exchangers and a fixed-bed precipitator between the wells of the doublet. The FIG aquifer is highly layered and a really anisotropic. The upper Franconia and Ironton-Galesville parts of the aquifer, those parts screened, have hydraulic conductivities of {approximately}0.6 and {approximately}1.0 m/d, respectively. Primary ions in the ambient ground water are calcium and magnesium bicarbonate. Ambient temperature FIG ground water is saturated with respect to calcium/magnesium bicarbonate. Heating the ground water caused most of the dissolved calcium to precipitate out as calcium carbonate in the heat exchanger and precipitator. Silica, calcium, and magnesium were significantly higher in recovered water than in injected water, suggesting dissolution of some constituents of the aquifer during the cycles. Further work on the ground water chemistry is required to understand water-rock interactions.

  6. Evaluation of longitudinal dispersivity estimates from forced-gradient tracer tests in heterogeneous aquifers

    USGS Publications Warehouse

    Tiedeman, C.R.; Hsieh, P.A.

    2002-01-01

    Converging radial-flow and two-well tracer tests are simulated in two-dimensional aquifers to investigate the effects of heterogeneity and forced-gradient test configuration on longitudinal dispersivity (??L) estimates, and to compare ??L estimates from forced-gradient tests with ??L values that characterize solute spreading under natural-gradient flow. Results indicate that in mildly heterogeneous aquifers, for tests with relatively large tracer transport distances, ??L estimates from the two test types are generally similar, and are also similar to ??L values determined from natural-gradient tracer simulations. In highly heterogeneous aquifers, ??L estimates from two-well tests are generally larger than those from radial-flow tests, and the ??L estimates from both test types are typically smaller than the ??L values determined from natural-gradient simulations.

  7. An evaluation of slug interference tests for aquifer characterization at the Hanford Site

    SciTech Connect

    Spane, F.A. Jr.; Thorne, P.D.

    1992-10-01

    Slug interference tests are conducted by instantaneously changing the water level in a well and monitoring the aquifer response at one or more observation wells. The applicability of this method for hydraulic characterization of a high permeability unconfined aquifer at the Hanford Site was evaluated. Analytical techniques were used to predict slug interference responses over a range of aquifer hydraulic conditions and observation well distances. This was followed by a field test of the proposed technique. The results showed that slug interference testing can be used to characterize aquifers having transmissivities up to 10{sup {minus}1} m{sup 2}/s compared to a maximum transmissivity of about 10{sup {minus}3} m{sup 2}/s for single-well slug tests. The amplitude of the pressure response measured at the observation well is primarily determined by aquifer storativity, while the time-lag of the pressure peak is mainly controlled by the transmissivity. Several recommendations are made optimizing the results of slug interference tests in higher permeability, unconfined to semiconfined aquifers.

  8. An evaluation of slug interference tests for aquifer characterization at the Hanford Site

    SciTech Connect

    Spane, F.A. Jr.; Thorne, P.D.

    1992-01-01

    Slug interference tests are conducted by instantaneously changing the water level in a well and monitoring the aquifer response at one or more observation wells. The applicability of this method for hydraulic characterization of a high permeability unconfined aquifer at the Hanford Site was evaluated. Analytical techniques were used to predict slug interference responses over a range of aquifer hydraulic conditions and observation well distances. This was followed by a field test of the proposed technique. The results showed that slug interference testing can be used to characterize aquifers having transmissivities up to 10{sup {minus}1} m{sup 2}/s compared to a maximum transmissivity of about 10{sup {minus}3} m{sup 2}/s for single-well slug tests. The amplitude of the pressure response measured at the observation well is primarily determined by aquifer storativity, while the time-lag of the pressure peak is mainly controlled by the transmissivity. Several recommendations are made optimizing the results of slug interference tests in higher permeability, unconfined to semiconfined aquifers.

  9. Test drilling and aquifer test in the Marburg schist near Mount Airy, Frederick County, Maryland

    USGS Publications Warehouse

    Meyer, Gerald

    1955-01-01

    This memorandum summarizes briefly the data obtained by test drilling and in an aquifer test at Mount Airy, Md. The tests were a part of the State - Federal cooperative study of the ground-water resources of Frederick County, and it is intended that a more complete analysis of the test data will be included in a future report describing the ground-water resource of Frederick County. The purpose of this memorandum is to make the test data immediately available to the general public. Mount Airy is located along the Carroll-Frederick County boundary bout 2 miles north of the intersection of U.S. Highway 40 with the county boundary. Its population is approximately 1,000. The municipal well field, consisting of two drilled wells (fig. 1) is in a valley about one-half mile west of the center of Mount Airy, within about 400 feet of a small stream, and north of Prospect Road. Well 1, about 40 feet north of Prospect Road, is 125 feet deep, 8 inches in diameter, and reportedly yielded 265 gallons per minute (gpm) in 1947 and 201 gpm in a half hour test in March 1955. The writer determined during the tests described in this memorandum that the well has about 34 feet of casing. Well 2, 85 feet north of well 1, is 96 feet deep, 8 inches in diameter, and reportedly yielded 120 gpm in 1947 and 127 gpm in a half hour test in March 1955. The wells are equipped with deep-well turbine pumps powered by electric motors. Cenorally only well 1 is used, and it is pumped for only a few short intervals each day to meet the water requirements of the town (about 75,000 - 80,000 gallons daily). The reported yields of these wells are considerably higher than the average for crystalline-rock wells in the Piedmont of Maryland. The test drilling was done under contract with Edward I. Brown, well driller, between May 3 and May 12, 1955. Water-supply facilities of the town of Mount Airy were kindly made available for the aquifer tests from May 22 to May 30, 1955. The pumping tests consisted of a

  10. Effects of Barometric Fluctuations on Well Water-Level Measurements and Aquifer Test Data

    SciTech Connect

    FA Spane, Jr.

    1999-12-16

    The Pacific Northwest National Laboratory, as part of the Hanford Groundwater Monitoring Project, examines the potential for offsite migration of contamination within underlying aquifer systems. Well water-level elevation measurements from selected wells within these aquifer systems commonly form the basis for delineating groundwater-flow patterns (i.e., flow direction and hydraulic gradient). In addition, the analysis of water-level responses obtained in wells during hydrologic tests provides estimates of hydraulic properties that are important for evaluating groundwater-flow velocity and transport characteristics. Barometric pressure fluctuations, however, can have a discernible impact on well water-level measurements. These barometric effects may lead to erroneous indications of hydraulic head within the aquifer. Total hydraulic head (i.e., sum of the water-table elevation and the atmospheric pressure at the water-table surface) within the aquifer, not well water-level elevation, is the hydrologic parameter for determining groundwater-flow direction and hydraulic gradient conditions. Temporal variations in barometric pressure may also adversely affect well water-level responses obtained during hydrologic tests. If significant, adjustments or removal of these barometric effects from the test-response record may be required for quantitative hydraulic property determination. This report examines the effects of barometric fluctuations on well water-level measurements and evaluates adjustment and removal methods for determining areal aquifer head conditions and aquifer test analysis. Two examples of Hanford Site unconfined aquifer tests are examined that demonstrate barometric response analysis and illustrate the predictive/removal capabilities of various methods for well water-level and aquifer total head values. Good predictive/removal characteristics were demonstrated with best corrective results provided by multiple-regression deconvolution methods.

  11. Determination of specific yield for the Biscayne Aquifer with a canal-drawdown test.

    PubMed

    Bolster, C H; Genereux, D P; Saiers, J E

    2001-01-01

    Data from a large-scale canal-drawdown test were used to estimate the specific yield (sy) of the Biscayne Aquifer, an unconfined limestone aquifer in southeast Florida. The drawdown test involved dropping the water level in a canal by about 30 cm and monitoring the response of hydraulic head in the surrounding aquifer. Specific yield was determined by analyzing data from the unsteady portion of the drawdown test using an analytical stream-aquifer interaction model (Zlotnik and Huang 1999). Specific yield values computed from drawdown at individual piezometers ranged from 0.050 to 0.57, most likely indicating heterogeneity of specific yield within the aquifer (small-scale variation in hydraulic conductivity may also have contributed to the differences in sy among piezometers). A value of 0.15 (our best estimate) was computed based on all drawdown data from all piezometers. We incorporated our best estimate of specific yield into a large-scale two-dimensional numerical MODFLOW-based ground water flow model and made predictions of head during a 183-day period at four wells located 337 to 2546 m from the canal. We found good agreement between observed and predicted heads, indicating our estimate of specific yield is representative of the large portion of the Biscayne Aquifer studied here. This work represents a practical and novel approach to the determination of a key hydrogeological parameter (the storage parameter needed for simulation and calculation of transient unconfined ground water flow), at a large spatial scale (a common scale for water resource modeling), for a highly transmissive limestone aquifer (in which execution of a traditional pump test would be impractical and would likely yield ambiguous results). Accurate estimates of specific yield and other hydrogeological parameters are critical for management of water supply, Everglades environmental restoration, flood control, and other issues related to the ground water hydrology of the Biscayne Aquifer.

  12. Laboratory Experiments to Evaluate Diffusion of 14C into Nevada Test Site Carbonate Aquifer Matrix

    SciTech Connect

    Ronald L. Hershey; William Howcroft; Paul W. Reimus

    2003-03-01

    Determination of groundwater flow velocities at the Nevada Test Site is important since groundwater is the principal transport medium of underground radionuclides. However, 14C-based groundwater velocities in the carbonate aquifers of the Nevada Test Site are several orders of magnitude slower than velocities derived from the Underground Test Area regional numerical model. This discrepancy has been attributed to the loss or retardation of 14C from groundwater into the surrounding aquifer matrix making 14C-based groundwater ages appear much older. Laboratory experiments were used to investigate the retardation of 14C in the carbonate aquifers at the Nevada Test Site. Three sets of experiments were conducted evaluating the diffusion of 14C into the carbonate aquifer matrix, adsorption and/or isotopic exchange onto the pore surfaces of the carbonate matrix, and adsorption and/or isotopic exchange onto the fracture surfaces of the carbonate aquifer. Experimental results a nd published aquifer matrix and fracture porosities from the Lower Carbonate Aquifer were applied to a 14C retardation model. The model produced an extremely wide range of retardation factors because of the wide range of published aquifer matrix and fracture porosities (over three orders of magnitude). Large retardation factors suggest that groundwater with very little measured 14C activity may actually be very young if matrix porosity is large relative to the fracture porosity. Groundwater samples collected from highly fractured aquifers with large effective fracture porosities may have relatively small correction factors, while samples from aquifers with a few widely spaced fractures may have very large correction factors. These retardation factors were then used to calculate groundwater velocities from a proposed flow path at the Nevada Test Site. The upper end of the range of 14C correction factors estimated groundwater velocities that appear to be at least an order of magnitude too high compared

  13. Borehole flowmeter measurements of horizontal groundwater flow before and during an aquifer test in central Indiana

    NASA Astrophysics Data System (ADS)

    Lampe, D. C.

    2009-12-01

    Horizontal borehole flowmeters will be used by the U.S. Geological Survey’s Indiana Water Science Center during an aquifer test in an outwash aquifer adjacent to the White River in central Indiana to determine directions and velocities of horizontal groundwater flow. Borehole flowmeters will provide point measurements of horizontal groundwater flow direction and velocity in four observation wells installed around the producing well. The point flow directions and velocities will be used to evaluate whether the aquifer test induces flow from the direction of nearby hydrologic boundaries: a river, and two adjacent tributaries, and/or from normally upgradient parts of the outwash aquifer system. Final calculations of flow velocity in the formation will include a correction factor based on laboratory flowmeter data. Correction factor data will be collected in the same type of well screen as the observation wells that is emplaced in a laboratory simulator packed with sand from the outwash aquifer and operated at known flow volumes and directions. Flowmeter-based groundwater flow directions and velocities that are made before and during the aquifer test, in combination with recorded water-level fluctuations, will be evaluated to understand groundwater/surface-water interactions and sources of groundwater to the producing well.

  14. Hot-water aquifer storage: A field test

    NASA Technical Reports Server (NTRS)

    Parr, A. D.; Molz, F. J.; Andersen, P. F.

    1980-01-01

    The basic water injection cycle used in a large-scale field study of heat storage in a confined aquifer near Mobile, Alabama is described. Water was pumped from an upper semi-confined aquifer, passed through a boiler where it was heated to a temperature of about 55 C, and injected into a medium sand confined aquifer. The injection well has a 6-inch (15-cm) partially-penetrating steel screen. The top of the storage formation is about 40 meters below the surface and the formation thickness is about 21 meters. In the first cycle, after a storage period of 51 days, the injection well was pumped until the temperature of the recovered water dropped to 33 c. At that point 55,300 cubic meters of water had been withdrawn and 66 percent of the injected energy had been recovered. The recovery period for the second cycle continued until the water temperature was 27.5 C and 100,100 cubic meters of water was recovered. At the end of the cycle about 90 percent of the energy injected during the cycle had been recovered.

  15. Pressure transient tests on geothermal wells in the Dogger aquifer, Paris Basin

    NASA Astrophysics Data System (ADS)

    giuglaris, elodie; hamm, virginie

    2014-05-01

    In this work, we propose a new interpretation of pressure transient tests conducted in more than sixty wells targeting the Dogger formation in the Paris basin. The most part of these wells were drilled during the eighties over a very short period of time in an urban area. The transient tests were only recorded during a pressure buildup and show that contrary to what has long been assumed the Dogger aquifer behavior is not homogeneous. The interpretation of the obtained data was mainly done with Horner's method, independently for each well, and assuming generally that the aquifer is homogeneous. Available data from pressure transient tests are limited because of the precision of the tools used, and because pressure buildup was only recorded during eight to twelve hours. The objective was to determine the average transmissivity and the skin factor in order to obtain the productivity of the wells. We gather all available data, including those obtained on the thirteen recent wells, and propose a new interpretation in terms of aquifer model. We use the pressure derivative method developed in the nineties for oil reservoirs which allows a better visualization of the model and of the heterogeneity of the aquifer. Most of the well tests have a derivative pressure curve with a slope equal to zero, that does not change after the well bore effects, confirming that the aquifer is relatively homogenous. However on a dozen of wells, data from pressure transient tests display singular behaviors that can be related to a double porosity or double permeability model for some wells and to a composite model for others. These observations question the validity of a homogeneous model for the Dogger aquifer in the Paris basin and the currently used parameters for the thermal and hydrodynamic predictive model of geothermal exploitation. Finally, this work increases our understanding of the Dogger aquifer in the Paris basin and will allow the optimization of the ongoing hydraulic tests and

  16. Estimation of hydraulic characteristics of the upper glacial and Magothy aquifers at East Meadow, New York, by use of aquifer tests

    USGS Publications Warehouse

    Prince, K.R.; Schneider, B.J.

    1989-01-01

    Drawdown and recovery data from two aquifer tests in central Nassau County, NY were used to calculate aquifer characteristics by several methods to aid in predicting the response of the aquifer system to stress. The first test, on May 12, 1978, entailed pumping the Magothy aquifer for 12 hours; the second on July 30-31, 1985, entailed pumping the upper glacial aquifer for 24 hours. Drawdown and recovery data from both tests were analyzed through analytical solutions and curve-matching procedures, and the resulting hydraulic values were used as initial values in a finite-element radial-flow numerical model to simulate the observed drawdowns and recoveries. Storativity values obtained by all methods were consistent with published estimates; but hydraulic conductivity values were higher than published estimates. The simple analytical solutions and curve-matching procedures gave reasonable values of most terms quickly, but the greatest confidence is in the estimates made with the finite-element model. These estimates for the Magothy aquifer were: horizontal hydraulic conductivity of 100 ft/d; ratio of horizontal to vertical conductivity, 5; and specific storage, 0.0001. Estimates for the upper glacial aquifer were: horizontal hydraulic conductivity, 380 ft/d; ratio of horizontal to vertical hydraulic conductivity, 2.5; and specific yield, 0.15. (USGS)

  17. Assessing an open-well aquifer test in fractured crystalline rock

    USGS Publications Warehouse

    Tiedeman, C.R.; Hsieh, P.A.

    2001-01-01

    Use of open wells to conduct aquifer tests in fractured crystalline rock aquifers is potentially problematic, because open wells can hydraulically connect highly permeable fracture zones at different depths within the rock. Because of this effect, it is questionable whether estimates of the hydraulic properties of the rock obtained from analysis of an open-well aquifer test in fractured crystalline rock are representative of the true rock properties. To address this issue, rock properties estimated from such a test are compared with rock properties estimated from an aquifer test at the same location in which packers were installed in wells to restrict vertical fluid movement along the wellbores. Results indicate that when the open-hole test is analyzed with a numerical model that accurately represents the three-dimensional heterogeneity structure in the wellfield, the open-hole test estimates of the rock hydraulic properties are similar to the packer-isolated test estimates. When the open-well test is analyzed using a model having an oversimplified representation of the rock heterogeneity, the estimates of rock transmissivity are similar to the transmissivity estimates from the packer-isolated test, but the storativity estimates are larger than the storativity estimates from the packer-isolated test. These results indicate the importance of accurately representing the rock heterogeneity structure when analyzing an open-hole aquifer test in fractured crystalline rock.Use of open wells to conduct aquifer tests in fractured crystalline rock aquifers is potentially problematic, because open wells can hydraulically connect highly permeable fracture zones at different depths within the rock. Because of this effect, it is questionable whether estimates of the hydraulic properties of the rock obtained from analysis of an open-well aquifer test in fractured crystalline rock are representative of the true rock properties. To address this issue, rock properties estimated from

  18. Aquifer sensitivity to pesticide leaching: Testing a soils and hydrogeologic index method

    USGS Publications Warehouse

    Mehnert, E.; Keefer, D.A.; Dey, W.S.; Wehrmann, H.A.; Wilson, S.D.; Ray, C.

    2005-01-01

    For years, researchers have sought index and other methods to predict aquifer sensitivity and vulnerability to nonpoint pesticide contamination. In 1995, an index method and map were developed to define aquifer sensitivity to pesticide leaching based on a combination of soil and hydrogeologic factors. The soil factor incorporated three soil properties: hydraulic conductivity, amount of organic matter within individual soil layers, and drainage class. These properties were obtained from a digital soil association map. The hydrogeologic factor was depth to uppermost aquifer material. To test this index method, a shallow ground water monitoring well network was designed, installed, and sampled in Illinois. The monitoring wells had a median depth of 7.6 m and were located adjacent to corn and soybean fields where the only known sources of pesticides were those used in normal agricultural production. From September 1998 through February 2001, 159 monitoring wells were sampled for 14 pesticides but no pesticide metabolites. Samples were collected and analyzed to assess the distribution of pesticide occurrence across three units of aquifer sensitivity. Pesticides were detected in 18% of all samples and nearly uniformly from samples from the three units of aquifer sensitivity. The new index method did not predict pesticide occurrence because occurrence was not dependent on the combined soil and hydrogeologic factors. However, pesticide occurrence was dependent on the tested hydrogeologic factor and was three times higher in areas where the depth to the uppermost aquifer was <6 m than in areas where the depth to the uppermost aquifer was 6 to <15 m. Copyright ?? 2005 National Ground Water Association.

  19. Tracer mass recovery in fractured aquifers estimated from multiple well tests.

    PubMed

    Sanford, William E; Cook, Peter G; Robinson, Neville I; Weatherill, Douglas

    2006-01-01

    Forced-gradient tracer tests in fractured aquifers often report low mass recoveries. In fractured aquifers, fractures intersected by one borehole may not be intersected by another. As a result (1) injected tracer can follow pathways away from the withdrawal well causing low mass recovery and (2) recovered water can follow pathways not connected to the injection well causing significant tracer dilution. These two effects occur along with other forms of apparent mass loss. If the strength of the connection between wells and the amount of dilution can be predicted ahead of time, tracer tests can be designed to optimize mass recovery and dilution. A technique is developed to use hydraulic tests in fractured aquifers to calculate the conductance (strength of connection) between well pairs and to predict mass recovery and amount of dilution during forced gradient tracer tests. Flow is considered to take place through conduits, which connect the wells to each other and to distant sources or sinks. Mass recovery is related to the proportion of flow leaving the injection well and arriving at the withdrawal well, and dilution is related to the proportion of the flow from the withdrawal well that is derived from the injection well. The technique can be used to choose well pairs for tracer tests, what injection and withdrawal rates to use, and which direction to establish the hydraulic gradient to maximize mass recovery and/or minimize dilution. The method is applied to several tracer tests in fractured aquifers in the Clare Valley, South Australia. PMID:16857034

  20. Heat tracer test in an alluvial aquifer: Field experiment and inverse modelling

    NASA Astrophysics Data System (ADS)

    Klepikova, Maria; Wildemeersch, Samuel; Hermans, Thomas; Jamin, Pierre; Orban, Philippe; Nguyen, Frédéric; Brouyère, Serge; Dassargues, Alain

    2016-09-01

    Using heat as an active tracer for aquifer characterization is a topic of increasing interest. In this study, we investigate the potential of using heat tracer tests for characterization of a shallow alluvial aquifer. A thermal tracer test was conducted in the alluvial aquifer of the Meuse River, Belgium. The tracing experiment consisted in simultaneously injecting heated water and a dye tracer in an injection well and monitoring the evolution of groundwater temperature and tracer concentration in the pumping well and in measurement intervals. To get insights in the 3D characteristics of the heat transport mechanisms, temperature data from a large number of observation wells closely spaced along three transects were used. Temperature breakthrough curves in observation wells are contrasted with what would be expected in an ideal layered aquifer. They reveal strongly unequal lateral and vertical components of the transport mechanisms. The observed complex behavior of the heat plume is explained by the groundwater flow gradient on the site and heterogeneities in the hydraulic conductivity field. Moreover, due to high injection temperatures during the field experiment a temperature-induced fluid density effect on heat transport occurred. By using a flow and heat transport numerical model with variable density coupled with a pilot point approach for inversion of the hydraulic conductivity field, the main preferential flow paths were delineated. The successful application of a field heat tracer test at this site suggests that heat tracer tests is a promising approach to image hydraulic conductivity field. This methodology could be applied in aquifer thermal energy storage (ATES) projects for assessing future efficiency that is strongly linked to the hydraulic conductivity variability in the considered aquifer.

  1. Simulation of a long-term aquifer test conducted near the Rio Grande, Albuquerque, New Mexico

    USGS Publications Warehouse

    McAda, Douglas P.

    2001-01-01

    A long-term aquifer test was conducted near the Rio Grande in Albuquerque during January and February 1995 using 22 wells and piezometers at nine sites, with the City of Albuquerque Griegos 1 production well as the pumped well. Griegos 1 discharge averaged about 2,330 gallons per minute for 54.4 days. A three-dimensional finite-difference ground-water-flow model was used to estimate aquifer properties in the vicinity of the Griegos well field and the amount of infiltration induced into the aquifer system from the Rio Grande and riverside drains as a result of pumping during the test. The model was initially calibrated by trial-and-error adjustments of the aquifer properties. The model was recalibrated using a nonlinear least-squares regression technique. The aquifer system in the area includes the middle Tertiary to Quaternary Santa Fe Group and post-Santa Fe Group valley- and basin-fill deposits of the Albuquerque Basin. The Rio Grande and adjacent riverside drains are in hydraulic connection with the aquifer system. The hydraulic-conductivity values of the upper part of the Santa Fe Group resulting from the model calibrated by trial and error varied by zone in the model and ranged from 12 to 33 feet per day. The hydraulic conductivity of the inner-valley alluvium was 45 feet per day. The vertical to horizontal anisotropy ratio was 1:140. Specific storage was 4 x 10-6 per foot of aquifer thickness, and specific yield was 0.15 (dimensionless). The sum of squared errors between the observed and simulated drawdowns was 130 feet squared. Not all aquifer properties could be estimated using nonlinear regression because of model insensitivity to some aquifer properties at observation locations. Hydraulic conductivity of the inner-valley alluvium, middle part of the Santa Fe Group, and riverbed and riverside-drain bed and specific yield had low sensitivity values and therefore could not be estimated. Of the properties estimated, hydraulic conductivity of the upper part of

  2. In situ testing of metallic iron nanoparticle mobility and reactivity in a shallow granular aquifer

    NASA Astrophysics Data System (ADS)

    Bennett, Peter; He, Feng; Zhao, Dongye; Aiken, Brian; Feldman, Lester

    2010-07-01

    This paper describes the results of a series of single well push-pull tests conducted to evaluate the in situ transport of carboxymethyl cellulose (CMC) stabilized nanoscale zero-valent iron (ZVI) particles in saturated sediments and their reactivity toward chlorinated ethenes. CMC-stabilized nanoscale ZVI particles were synthesized on site by reducing ferrous ions with borohydride in water in the presence of CMC. Nanoscale ZVI and bimetallic ZVI-Pd nanoparticle suspensions were prepared and injected into depth-discrete aquifer zones during three push-pull tests. The injected nanoparticle suspensions contained a conservative tracer (Br -) and were allowed to reside in the aquifer pore space for various time periods prior to recovery by groundwater extraction. The comparison between Br - and Fe concentrations in extracted groundwater samples indicated that the CMC-stabilized nanoscale ZVI particles were mobile in the aquifer but appeared to lose mobility with time, likely due to the interactions between particles and aquifer sediments. After 13 h in the aquifer, the nanoscale ZVI particles became essentially immobilized. During the push-pull test with injection of Fe-Pd nanoparticles, ethane concentrations increased from non-detectable to 65 μg/L in extracted groundwater within less than 2 h of reaction time, indicating the rapid abiotic degradation of chlorinated ethenes. The amount of total chlorinated ethene mass destroyed was low presumably because the injected solutions "pushed" the dissolved chlorinated ethenes away from the injection well, without substantial mixing, and because stationary (sorbed) chlorinated ethene mass on the aquifer sediments was low. In situ remediation programs using highly reactive metallic nanoparticles should incorporate delivery methods that maintain high groundwater pore velocities during injection to increase advective transport distances (e.g. groundwater circulation wells). Also, source zones with abundant stationary

  3. In situ testing of metallic iron nanoparticle mobility and reactivity in a shallow granular aquifer.

    PubMed

    Bennett, Peter; He, Feng; Zhao, Dongye; Aiken, Brian; Feldman, Lester

    2010-07-30

    This paper describes the results of a series of single well push-pull tests conducted to evaluate the in situ transport of carboxymethyl cellulose (CMC) stabilized nanoscale zero-valent iron (ZVI) particles in saturated sediments and their reactivity toward chlorinated ethenes. CMC-stabilized nanoscale ZVI particles were synthesized on site by reducing ferrous ions with borohydride in water in the presence of CMC. Nanoscale ZVI and bimetallic ZVI-Pd nanoparticle suspensions were prepared and injected into depth-discrete aquifer zones during three push-pull tests. The injected nanoparticle suspensions contained a conservative tracer (Br(-)) and were allowed to reside in the aquifer pore space for various time periods prior to recovery by groundwater extraction. The comparison between Br(-) and Fe concentrations in extracted groundwater samples indicated that the CMC-stabilized nanoscale ZVI particles were mobile in the aquifer but appeared to lose mobility with time, likely due to the interactions between particles and aquifer sediments. After 13 h in the aquifer, the nanoscale ZVI particles became essentially immobilized. During the push-pull test with injection of Fe-Pd nanoparticles, ethane concentrations increased from non-detectable to 65 microg/L in extracted groundwater within less than 2 h of reaction time, indicating the rapid abiotic degradation of chlorinated ethenes. The amount of total chlorinated ethene mass destroyed was low presumably because the injected solutions "pushed" the dissolved chlorinated ethenes away from the injection well, without substantial mixing, and because stationary (sorbed) chlorinated ethene mass on the aquifer sediments was low. In situ remediation programs using highly reactive metallic nanoparticles should incorporate delivery methods that maintain high groundwater pore velocities during injection to increase advective transport distances (e.g. groundwater circulation wells). Also, source zones with abundant stationary

  4. In situ testing of metallic iron nanoparticle mobility and reactivity in a shallow granular aquifer.

    PubMed

    Bennett, Peter; He, Feng; Zhao, Dongye; Aiken, Brian; Feldman, Lester

    2010-07-30

    This paper describes the results of a series of single well push-pull tests conducted to evaluate the in situ transport of carboxymethyl cellulose (CMC) stabilized nanoscale zero-valent iron (ZVI) particles in saturated sediments and their reactivity toward chlorinated ethenes. CMC-stabilized nanoscale ZVI particles were synthesized on site by reducing ferrous ions with borohydride in water in the presence of CMC. Nanoscale ZVI and bimetallic ZVI-Pd nanoparticle suspensions were prepared and injected into depth-discrete aquifer zones during three push-pull tests. The injected nanoparticle suspensions contained a conservative tracer (Br(-)) and were allowed to reside in the aquifer pore space for various time periods prior to recovery by groundwater extraction. The comparison between Br(-) and Fe concentrations in extracted groundwater samples indicated that the CMC-stabilized nanoscale ZVI particles were mobile in the aquifer but appeared to lose mobility with time, likely due to the interactions between particles and aquifer sediments. After 13 h in the aquifer, the nanoscale ZVI particles became essentially immobilized. During the push-pull test with injection of Fe-Pd nanoparticles, ethane concentrations increased from non-detectable to 65 microg/L in extracted groundwater within less than 2 h of reaction time, indicating the rapid abiotic degradation of chlorinated ethenes. The amount of total chlorinated ethene mass destroyed was low presumably because the injected solutions "pushed" the dissolved chlorinated ethenes away from the injection well, without substantial mixing, and because stationary (sorbed) chlorinated ethene mass on the aquifer sediments was low. In situ remediation programs using highly reactive metallic nanoparticles should incorporate delivery methods that maintain high groundwater pore velocities during injection to increase advective transport distances (e.g. groundwater circulation wells). Also, source zones with abundant stationary

  5. Summary of available hydrogeologic data collected between 1973 and 1995 and information on all permeability data and aquifer tests for the Capitan Aquifer, Eddy and Lea Counties, New Mexico

    USGS Publications Warehouse

    Huff, G.F.

    1997-01-01

    This report summarizes the availability of water-level data for the Capitan aquifer and evaluates the condition of wells in the Capitan aquifer observation-well network. The report summarizes water-level and water-quality data for the Capitan aquifer, including water-level data specifically for the Tansill Formation, collected from 1973 through 1995. The report summarizes aquifer- test and permeability data for the Capitan aquifer and shows the location of wells stored in the New Mexico State Engineer Office data base that tap the Capitan aquifer.

  6. Analysis of three tests of the unconfined aquifer in southern Nassau County, Long Island, New York

    USGS Publications Warehouse

    Lindner, J.B.; Reilly, T.E.

    1982-01-01

    Drawdown and recovery data from three 2-day aquifer tests (OF) the unconfined (water-table) aquifer in southern Nassau County, N.Y., during the fall of 1979, were analyzed. Several simple analytical solutions, a typecurve-matching procedure, and a Galerkin finite-element radial-flow model were used to determine hydraulic conductivity, ratio of horizontal to vertical hydraulic conductivity, and specific yield. Results of the curve-matching procedure covered a broad range of values that could be narrowed through consideration of data from other sources such as published reports, drillers ' logs, or values determined by analytical solutions. Analysis by the radial-flow model was preferred because it allows for vertical variability in aquifer properties and solves the system for all observation points simultaneously, whereas the other techniques treat the aquifer as homogeneous and must treat each observation well separately. All methods produced fairly consistent results. The ranges of aquifer values at the three sites were: horizontal hydraulic conductivity, 140 to 380 feet per day; transmissivity 11,200 to 17,100 feet squared per day; ratio of horizontal to vertical hydraulic conductivity 2.4:1 to 7:1, and specific yield , 0.13 to 0.23. (USGS)

  7. Evaluation of unconfined-aquifer parameters from pumping test data by nonlinear least squares

    USGS Publications Warehouse

    Heidari, M.; Moench, A.

    1997-01-01

    Nonlinear least squares (NLS) with automatic differentiation was used to estimate aquifer parameters from drawdown data obtained from published pumping tests conducted in homogeneous, water-table aquifers. The method is based on a technique that seeks to minimize the squares of residuals between observed and calculated drawdown subject to bounds that are placed on the parameter of interest. The analytical model developed by Neuman for flow to a partially penetrating well of infinitesimal diameter situated in an infinite, homogeneous and anisotropic aquifer was used to obtain calculated drawdown. NLS was first applied to synthetic drawdown data from a hypothetical but realistic aquifer to demonstrate that the relevant hydraulic parameters (storativity, specific yield, and horizontal and vertical hydraulic conductivity) can be evaluated accurately. Next the method was used to estimate the parameters at three field sites with widely varying hydraulic properties. NLS produced unbiased estimates of the aquifer parameters that are close to the estimates obtained with the same data using a visual curve-matching approach. Small differences in the estimates are a consequence of subjective interpretation introduced in the visual approach.

  8. Results of Aquifer Tests Performed Near R-Area, Savannah River Site

    SciTech Connect

    Hiergesell, R.A.

    2001-01-31

    The aquifer testing described in this report was conducted in response to USEPA comments (WSRC, 1998) on the Rev. 0 R-Reactor Seepage Basins RFI/RI Report (WSRC, 1998a), Appendix G, Groundwater Contaminant Transport Modeling for the R-Reactor Seepage Basins (RRSB)/108-4R Overflow Basin Operable Unit. The R-area regional flow model described in Appendix G of the RFI/RI is based on small-scale and/or indirect measures of hydraulic conductivity, including laboratory tests, slug tests, cone penetration testing (CPT) and lithologic core descriptions. The USEPA proposed and SRS- agreed that large-scale conductivity estimates from multiple well pumping tests would be beneficial for validating the model conductivity field. Overall, the aquifer test results validate the 1998 R-area regional groundwater flow model.

  9. A Microcomputer Program for Evaluating Pumping Test Results for Confined Aquifers.

    ERIC Educational Resources Information Center

    Smith, Stephen M.

    1986-01-01

    Describes an interactive, self-prompting BASIC program that can be incorporated in introductory and intermediate hydrology courses. Exlains how the program can be used to evaluate pumping test data and also to calculate transmissivity and storativity values of confined aquifers. The program is written for the IBM PC. (ML)

  10. Field testing of a high-temperature aquifer thermal energy storage system

    SciTech Connect

    Sterling, R.L.; Hoyer, M.C.

    1989-03-01

    The University of Minnesota Aquifer Thermal Energy Storage (ATES) System has been operated as a field test facility for the past six years. Four short-term and two long-term cycles have been completed to data providing a greatly increased understanding of the efficiency and geochemical effects of high-temperature aquifer thermal energy storage. A third long-term cycle is currently being planned to operate the ATES system in conjunction with a real heating load and to further study the geochemical impact on the aquifer from heated waste storage cycles. The most critical activities in the preparation for the next cycle have proved to be the applications for the various permits and variances necessary to conduct the third cycle and the matching of the characteristics of the ATES system during heat recovery with a suitable adjacent building thermal load.

  11. AQUIFER TESTING AND REBOUND STUDY IN SUPPORT OF THE 100-H DEEP CHROMIUM INVESTIGATION

    SciTech Connect

    SMOOT JL

    2010-11-05

    The 100-HR-3 Groundwater Operable Unit (OU) second Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) 5-year review (DOEIRL-2006-20, The Second CERCLA Five-Year Review Report for the Hanford Site) set a milestone to conduct an investigation of deep hexavalent chromium contamination in the sediments of the Ringold upper mud (RUM) unit, which underlies the unconfined aquifer in the 100-H Area. The 5-year review noted that groundwater samples from one deep well extending below the aquitard (i.e., RUM) exceeded both the groundwater standard of 48 parts per billion (ppb) (Ecology Publication 94-06, Model Toxics Control Act Cleanup Statute and Regulation) and the federal drinking water standard of 100 {mu}g/L for hexavalent chromium. The extent of hexavalent chromium contamination in this zone is not well understood. Action 12-1 from the 5-year review is to perform additional characterization of the aquifer below the initial aquitard. Field characterization and aquifer testing were performed in the Hanford Site's 100-H Area to address this milestone. The aquifer tests were conducted to gather data to answer several fundamental questions regarding the presence of the hexavalent chromium in the deep sediments of the RUM and to determine the extent and magnitude of deeper contamination. The pumping tests were performed in accordance with the Description of Work for Aquifer Testing in Support of the 100-H Deep Chromium Investigation (SGW-41302). The specific objectives for the series of tests were as follows: (1) Evaluate the sustainable production of the subject wells using step-drawdown and constant-rate pumping tests. (2) Collect water-level data to evaluate the degree of hydraulic connection between the RUM and the unconfined (upper) aquifer (natural or induced along the well casing). (3) Evaluate the hydraulic properties of a confined permeable layer within the RUM.; (4) Collect time-series groundwater samples during testing to

  12. Constant-head pumping test of a multiaquifer well to determine characteristics of individual aquifers

    USGS Publications Warehouse

    Bennett, Gordon D.; Patten, E.P.

    1962-01-01

    This report describes the theory and field procedures for determining the transmissibility and storage coefficients and the original hydrostatic head of each aquifer penetrated by a multiaquifer well. The procedure involves pumping the well in such a manner that the drawdown of water level is constant while the discharges of the different aquifers are measured by means of borehole flowmeters. The theory is developed by analogy to the heat-flow problem solved by Smith. The internal discharge between aquifers after the well is completed is analyzed as the first step. Pumping at constant, drawdown constitutes the second step. Transmissibility and storage coefficients are determined by a method described by Jacob and Lohman, after the original internal discharge to or from the aquifer has been compensated for in the calculations. The original hydrostatic head of each aquifer is then determined by resubstituting the transmissibility and storage coefficients into the first step of the analysis. The method was tested on a well in Chester County, Pa., but the results were not entirely satisfactory, owing to the lack of sufficiently accurate methods of flow measurement and, probably, to the effects of entrance losses in the well. The determinations of the transmissibility coefficient and static head can be accepted as having order-of-magnitude significance, but the determinations of the storage coefficient, which is highly sensitive to experimental error, must be rejected. It is felt that better results may be achieved in the future, as more reliable devices for metering the flow become available and as more is learned concerning the nature of entrance losses. If accurate data can be obtained, recently developed techniques of digital or analog computation may permit determination of the response of each aquifer in the well to any form of pumping.

  13. Estimating transmissivity from single-well pumping tests in heterogeneous aquifers

    NASA Astrophysics Data System (ADS)

    Pechstein, Armin; Attinger, Sabine; Krieg, Ronald; Copty, Nadim K.

    2016-01-01

    Although aquifers are naturally heterogeneous, the interpretation of pumping tests is commonly performed under the assumption of aquifer homogeneity. This yields interpreted hydraulic parameters averaged over a domain of uncertain extent which disguises their relation to the underlying heterogeneity. In this study, we numerically investigate the sensitivity of the transient drawdown at the pumping well, to nonuniform distributions of transmissivity in confined aquifers. Frechet kernels and their time derivative are used to estimate two spatially averaged transmissivities, denoted the equivalent and interpreted transmissivity, Teq and Tin, respectively, for the case of single-well pumping tests. Interrelating Teq and Tin is achieved by modeling Tin in terms of a distance dependent, radially heterogeneous field. In weakly heterogeneous aquifers, Teq approximates TPW, the local transmissivity at the pumped well. With increasing degree of heterogeneity, Teq deviates from TPW as pumping propagates. Tin starts at TPW, approaching the spatial geometric mean of transmissivity during late pumping times. Limits of the proposed spatial weighting functions are investigated by treating the interpreted storativity, Sest, as an indicator for flow connectivity. It is shown numerically that the spatial weights for Teq and Tin agree well to the underlying heterogeneity if . Finally, implications for applying the concepts of Teq and Tin to heterogeneous domains, and, for real world applications are discussed. It is found that time-dependent spatial averages of Tin agree well with estimates of the interpreted transmissivity from the Continuous-Derivation method.

  14. Aquifer Testing Recommendations for Supporting Phase II of the T Area Technetium-99 Data Objectives Process

    SciTech Connect

    Spane, Frank A.

    2008-04-02

    Aquifer characterization needs are currently being assessed to optimize pump-and-treat remedial strategies within the 200-ZP-1 operable unit, specifically for the immediate area of the 241-T Tank Farm. This report provides a general discussion of the six identified hydrologic test methods for possible subsequent characterization within the 241-T Tank Farm area and details for implementing the large-scale recovery test after terminating pumping at the 241-Tank Farm extraction well locations.

  15. Estimating parameters of aquifer heterogeneity using pumping tests - implications for field applications

    NASA Astrophysics Data System (ADS)

    Zech, Alraune; Arnold, Sven; Schneider, Christoph; Attinger, Sabine

    2015-09-01

    The knowledge of subsurface heterogeneity is a prerequisite to describe flow and transport in porous media. Of particular interest are the variance and the correlation scale of hydraulic conductivity. In this study, we present how these aquifer parameters can be inferred using empirical steady state pumping test data. We refer to a previously developed analytical solution of "effective well flow" and examine its applicability to pumping test data as under field conditions. It is examined how the accuracy and confidence of parameter estimates of variance and correlation length depend on the number and location of head measurements. Simulations of steady state pumping tests in a confined virtual aquifer are used to systematically reduce sampling size while determining the rating of the estimates at each level of data density. The method was then applied to estimate the statistical parameters of a fluvial heterogeneous aquifer at the test site Horkheimer Insel, Germany. We conclude that the "effective well flow" solution is a simple alternative to laboratory investigations to estimate the statistical heterogeneity parameter using steady state pumping tests. However, the accuracy and uncertainty of the estimates depend on the design of the field study. In this regard, our results can help to improve the conceptual design of pumping tests with regard to the parameter of interest.

  16. Combined use of heat and saline tracer to estimate aquifer properties in a forced gradient test

    NASA Astrophysics Data System (ADS)

    Colombani, N.; Giambastiani, B. M. S.; Mastrocicco, M.

    2015-06-01

    Usually electrolytic tracers are employed for subsurface characterization, but the interpretation of tracer test data collected by low cost techniques, such as electrical conductivity logging, can be biased by cation exchange reactions. To characterize the aquifer transport properties a saline and heat forced gradient test was employed. The field site, located near Ferrara (Northern Italy), is a well characterized site, which covers an area of 200 m2 and is equipped with a grid of 13 monitoring wells. A two-well (injection and pumping) system was employed to perform the forced gradient test and a straddle packer was installed in the injection well to avoid in-well artificial mixing. The contemporary continuous monitor of hydraulic head, electrical conductivity and temperature within the wells permitted to obtain a robust dataset, which was then used to accurately simulate injection conditions, to calibrate a 3D transient flow and transport model and to obtain aquifer properties at small scale. The transient groundwater flow and solute-heat transport model was built using SEAWAT. The result significance was further investigated by comparing the results with already published column experiments and a natural gradient tracer test performed in the same field. The test procedure shown here can provide a fast and low cost technique to characterize coarse grain aquifer properties, although some limitations can be highlighted, such as the small value of the dispersion coefficient compared to values obtained by natural gradient tracer test, or the fast depletion of heat signal due to high thermal diffusivity.

  17. Summary of three dimensional pump testing of a fractured rock aquifer in the western Siberian Basin

    SciTech Connect

    Nichols, R.L.; Looney, B.B.; Eddy-Dilek, C.A.; Drozhko, E.G.; Glalolenko, Y.V.; Mokrov, Y.G.; Ivanov, I.A.; Glagolev, A.V.; Vasil`kova, N.A.

    1996-10-30

    A group of scientists from the Savannah River Technology Center and Russia successfully completed a 17 day field investigation of a fractured rock aquifer at the MAYAK PA nuclear production facility in Russia. The test site is located in the western Siberian Basin near the floodplain of the Mishelyak river. The fractured rock aquifer is composed of orphyrites, tuff, tuffbreccia and lava and is overlain by 0.5--12 meters of elluvial and alluvial sediments. A network of 3 uncased wells (176, 1/96, and 2/96) was used to conduct the tests. Wells 176 and 2/96 were used as observation wells and the centrally located well 1/96 was used as the pumping well. Six packers were installed and inflated in each of the observation wells at a depth of up to 85 meters. The use of 6 packers in each well resulted in isolating 7 zones for monitoring. The packers were inflated to different pressures to accommodate the increasing hydrostatic pressure. A straddle packer assembly was installed in the pumping well to allow testing of each of the individual zones isolated in the observation wells. A constant rate pumping test was run on each of the 7 zones. The results of the pumping tests are included in Appendix A. The test provided new information about the nature of the fractured rock aquifers in the vicinity of the Mishelyak river and will be key information in understanding the behavior of contaminants originating from process wastes discharged to Lake Karachi. Results from the tests will be analyzed to determine the hydraulic properties of different zones within the fractured rock aquifer and to determine the most cost effective clean-up approach for the site.

  18. Data from core analyses, aquifer testing, and geophysical logging of Denver Basin bedrock aquifers at Castle Pines, Colorado

    USGS Publications Warehouse

    Robson, S.G.; Banta, E.R.

    1993-01-01

    This report contains data pertaining to the geologic and hydrologic characteristics of the bedrock aquifers of the Denver basin at a site near Castle Pines, Colorado. Data consist of a lithologic- description of about 2,400 ft of drill core and laboratory determinations of mineralogy, grain size, bulk and grain density, porosity, specific yield, and specific retention for selected core samples. Water-level data, atmospheric-pressure measurements, aquifer-compression measurements, and borehole geophysical logs also are included.

  19. Variations in hydraulic conductivity with scale of measurement during aquifer tests in heterogeneous, porous carbonate rocks

    NASA Astrophysics Data System (ADS)

    Schulze-Makuch, Dirk; Cherkauer, Douglas S.

    Previous studies have shown that hydraulic conductivity of an aquifer seems to increase as the portion of the aquifer tested increases. To date, such studies have all relied on different methods to determine hydraulic conductivity at each scale of interest, which raises the possibility that the observed increase in hydraulic conductivity is due to the measurement method, not to the scale. This study analyzes hydraulic conductivity with respect to scale during individual aquifer tests in porous, heterogeneous carbonate rocks in southeastern Wisconsin, USA. Results from this study indicate that hydraulic conductivity generally increases during an individual test as the volume of aquifer impacted increases, and the rate of this increase is the same as the rate of increase determined by using different measurement methods. Thus, scale dependence of hydraulic conductivity during single tests does not depend on the method of measurement. This conclusion is supported by 22 of 26 aquifer tests conducted in porous-flow-dominated carbonate units within the aquifer. Instead, scale dependency is probably caused by heterogeneities within the aquifer, a conclusion supported by digital simulation. All of the observed types of hydraulic-conductivity variations with scale during individual aquifer tests can be explained by a conceptual model of a simple heterogeneous aquifer composed of high-conductivity zones within a low-conductivity matrix. Résumé Certaines études ont montré que la conductivité hydraulique d'un aquifère semble augmenter en même temps que la partie testée de l'aquifère s'étend. Jusqu'à présent, ces études ont toutes reposé sur des méthodes de détermination de la conductivité hydraulique différentes pour chaque niveau d'échelle, ce qui a conduit à penser que l'augmentation observée de la conductivité hydraulique pouvait être due aux méthodes de mesure et non à l'effet d'échelle. Cette étude analyse la conductivité hydraulique par

  20. Analytical solutions for analysing pumping tests in a sub-vertical and anisotropic fault zone draining shallow aquifers

    NASA Astrophysics Data System (ADS)

    Dewandel, B.; Aunay, B.; Maréchal, J. C.; Roques, C.; Bour, O.; Mougin, B.; Aquilina, L.

    2014-02-01

    We present new analytical solutions for examining the influence, during a pumping test in a well, of an infinite linear and anisotropic strip-aquifer that drains shallow aquifers of different diffusivity and thickness. The whole system is confined and the aquifer geometry can be represented by a 'T', an aquifer geometry resembling a sub-vertical fault or a sub-vertical vein cross-cutting shallower aquifers. The proposed solutions are based upon an unconventional application of well-image theory, without limitation of the diffusivity contrast between the three domains. Solutions for drawdown were developed for the three domains, i.e. the strip-aquifer and the two shallow compartments, and flow signatures are discussed in detail and compared to numerical modelling. The proposed solutions are not shown to be exact solutions to the appropriate partial differential equation, but very good and useful approximations. The solutions were applied to a 63-day pumping test in a steep fault zone in crystalline aquifer rock of Brittany, France. After that, the flow contributions of the fault zone and of the shallow aquifers deduced from groundwater dating were compared to analytical solutions. The solutions and theoretical type-curve examples can help in understanding flow processes from tests conducted in settings that are similar to such a conceptual model.

  1. Analysis of aquifer tests conducted in borehole USW G-2, 1996, Yucca Mountain, Nevada

    SciTech Connect

    O`Brien, G.M.

    1998-08-01

    Borehole USW G-2 is located north of Yucca Mountain in a large-hydraulic-gradient area. Two single-borehole aquifer tests were conducted in the borehole during 1996. A 54.9-hour pumping period was conducted February 6--8, 1996, and a 408-hour pumping period was conducted April 8--25, 1996. The purpose of testing was to obtain estimates of the aquifer-system transmissivity and to determine if perched water was affecting the observed water level in borehole USW G-2. This report presents and analyzes data collected between February 6 and December 17, 1996. Analysis of the aquifer-test data indicated that fracture flow, dual-porosity flow, and boundary-affected flow conditions were observed in the drawdown and recovery data. Transmissivity estimates ranged from 2.3 to 12 meters squared per day. The most representative transmissivity estimate for the interval tested is the early-time mean transmissivity of 9.4 meters squared per day. The Calico Hills Formation was the primary formation tested, but the top 3 meters of the nonpumping water column was within the overlying Topopah Spring Tuff. Persistent residual drawdown following pumping more than 6 million liters of water during aquifer testing may indicate that the bore-hole intersected a perched water body. After 236 days of recovery, residual drawdown was 0.5 meter. The quantitative effect of the perched water on the observed water level in borehole USW G-2, however, cannot be determined with the available data.

  2. Dynamic interpretation of slug tests in highly permeable aquifers

    USGS Publications Warehouse

    Zurbuchen, B.R.; Zlotnik, V.A.; Butler, J.J.

    2002-01-01

    Considerable progress has been made in developing a theoretical framework for modeling slug test responses in formations with high hydraulic conductivity K. However, several questions of practical significance remain unresolved. Given the rapid and often oscillatory nature of test responses, the traditional hydrostatic relationship between the water level and the transducer-measured head in the water column may not be appropriate. A general dynamic interpretation is proposed that describes the relationship between water level response and transducer-measured head. This theory is utilized to develop a procedure for transforming model-generated water level responses to transducer readings. The magnitude of the difference between the actual water level position and the apparent position based on the transducer measurement is a function of the acceleration and velocity of the water column, test geometry, and depth of the transducer. The dynamic approach explains the entire slug test response, including the often-noted discrepancy between the actual initial water level displacement and that measured by a transducer in the water column. Failure to use this approach can lead to a significant underestimation of K when the transducer is a considerable distance below the static water level. Previous investigators have noted a dependence of test responses on the magnitude of the initial water level displacement and have developed various approximate methods for analyzing such data. These methods are re-examined and their limitations clarified. Practical field guidelines are proposed on the basis of findings of this work. The soundness of the dynamic approach is demonstrated through a comparison of K profiles from a series of multilevel slug tests with those from dipole-flow tests performed in the same wells.

  3. Estimating transmissivity and storage properties from aquifer tests in the Southern Lihue Basin, Kauai, Hawaii

    USGS Publications Warehouse

    Gingerich, Stephen B.

    1999-01-01

    The results show that transmissivity in the Lihue basin ranges over several orders of magnitude, 42 to 7,900 square feet per day, but is generally lower than reported values of transmissivity of other basaltic aquifers in Hawaii. Estimates of confined-aquifer storage coefficient range from 1.3x10-4 to 8.2x10-2. The hydraulic conductivity estimates obtained using an elliptical-equation method compare favorably with the results obtained from the generally more-accepted curvematching methods. No significant difference is apparent between the estimated transmissivity of the Koloa Volcanics and the Waimea Canyon Basalt in the study area. An analysis of the lithology penetrated by the wells indicates the transmissivity is probably controlled mainly by the stratigraphic position of the layers penetrated by the well. The range of transmissivity values estimated for the southern Lihue basin is lower than reported values from aquifer tests at wells penetrating postshield-stage or rejuvenation-stage lava flows on other Hawaiian islands. This range is one to four orders of magnitude lower than most reported values for dike-free basalt aquifers in Hawaii.

  4. Aquifer recharge with reclaimed water in the Llobregat Delta. Laboratory batch experiments and field test site.

    NASA Astrophysics Data System (ADS)

    Tobella, J.

    2010-05-01

    Summary Spain, as most other Mediterranean countries, faces near future water shortages, generalized pollution and loss of water dependent ecosystems. Aquifer recharge represents a promising option to become a source for indirect potable reuse purposes but presence of pathogens as well as organic and inorganic pollutants should be avoided. To this end, understanding the processes of biogeochemical degradation occurring within the aquifer during infiltration is capital. A set of laboratory batch experiments has been assembled in order to assess the behaviour of selected pesticides, drugs, estrogens, surfactant degradation products, biocides and phthalates under different redox conditions. Data collected during laboratory experiments and monitoring activities at the Sant Vicenç dels Horts test site will be used to build and calibrate a numerical model (i) of the physical-chemical-biochemical processes occurring in the batches and (ii) of multicomponent reactive transport in the unsaturated/saturated zone at the test site. Keywords Aquifer recharge, batch experiments, emerging micropollutants, infiltration, numerical model, reclaimed water, redox conditions, Soil Aquifer Treatment (SAT). 1. Introduction In Spain, the Llobregat River and aquifers, which supply water to Barcelona, have been overexploited for years and therefore, suffer from serious damages: the river dries up on summer, riparian vegetation has disappeared and seawater has intruded the aquifer. In a global context, solutions to water stress problems are urgently needed yet must be sustainable, economical and safe. Recent developments of analytical techniques detect the presence of the so-called "emerging" organic micropollutants in water and soils. Such compounds may affect living organisms when occurring in the environment at very low concentrations (microg/l or ng/l). In wastewater and drinking water treatment plants, a remarkable removal of these chemicals from water can be obtained only using

  5. Multispecies reactive tracer test in an aquifer with spatially variable chemical conditions

    USGS Publications Warehouse

    Davis, J.A.; Kent, D.B.; Coston, J.A.; Hess, K.M.; Joye, J.L.

    2000-01-01

    A field investigation of multispecies reactive transport was conducted in a well-characterized, sand and gravel aquifer on Cape Cod, Massachusetts. The aquifer is characterized by regions of differing chemical conditions caused by the disposal of secondary sewage effluent. Ten thousand liters of groundwater with added tracers (Br, Cr(VI), and BDTA complexed with Pb, Zn, Cu, and Ni) were injected into the aquifer and distributions of the tracers were monitored for 15 months. Most of the tracers were transported more than 200 m; transport was quantified using spatial moments computed from the results of a series of synoptic samplings. Cr(VI) transport was retarded relative to Br; the retardation factor varied from 1.1 to 2.4 and was dependent on chemical conditions. At 314 days after the injection, dissolved Cr(VI) mass in the tracer cloud had decreased 85%, with the likely cause being reduction to Cr(III) in a suboxic region of the aquifer. Transport of the metal-EDTA complexes was affected by aqueous complexation, adsorption, and dissolution-precipitation reactions of Fe oxyhydroxide minerals in the aquifer sediments. Dissolved Pb-EDTA complexes disappeared from the tracer cloud within 85 days, probably due to metal exchange reactions with Fe and adsorbed Zn (present prior to the injection from contamination by the sewage effluent). About 30% of the Cu-EDTA complexes remained within the tracer cloud 314 days after injection, even though the thermodynamic stability of the Pb-EDTA complex is greater than Cu-EDTA. It is hypothesized that stronger adsorption of Pb2+ to the aquifer sediments causes the Pb-EDTA complex to disassociate to a greater degree than the Cu-EDTA complex. The mass of dissolved Zn-EDTA increased during the first 175 days of the tracer test to 140% of the mass injected, with the increase due to desorption of sewage-derived Zn. Dissolved Ni-EDTA mass remained nearly constant throughout the tracer test, apparently only participating in reversible

  6. Data for ground-water test hole near Nicolaus, Central Valley aquifer project, California

    USGS Publications Warehouse

    French, James J.; Page, R.W.; Bertoldi, Gilbert L.

    1983-01-01

    Preliminary data are provided for the third of seven test holes drilled as a part of the Central Valley Aquifer Project which is part of the National Regional Aquifer Systems Analysis Program. The test hole was drilled in the SW 1/4 NE 1/4 sec. 2, T.12N., R.3E., Sutter County, California, about 1 1/2 miles northwest of the town of Nicolaus. Drilled to a depth of 1,150 feet below land surface, the hole is cased to a depth of 100 feet and equipped with three piezometer tubes to depths of 311, 711, and 1,071 feet. A 5-foot well screen is set in sand at the bottom of each piezometer. Each screened interval has a cement plug above and below it to isolate it from other parts of the aquifer, and the well bore is filled between the plugs with sediment. Thirty-one cores and 34 sidewall cores were recovered. Laboratory tests were made for minerology, consolidation, grain-size distribution, Atterberg limits, X-ray diffraction, thermal conductivity, and chemical analysis of water. Geophysical and thermal gradient logs were made. The hole is sampled periodically for chemical analysis of the three tapped zones and measured for water level. This report presents methods used to obtain field samples, laboratory procedures, and the data obtained. (USGS)

  7. Data for ground-water test hole near Butte City, Central Valley aquifer project, California

    USGS Publications Warehouse

    French, James J.; Page, R.W.; Bertoldi, G.L.

    1983-01-01

    This report provides preliminary data for the third of seven test holes drilled as part of the Central Valley Aquifer Project which is part of the National Regional Aquifer Systems Analysis Program. The test hole was drilled in the SW 1/4 NE 1/4 sec. 32, T. 19 N., R. 1 W., Glenn County, California, about one-half mile south of the town of Butte City. Drilled to a depth of 1,432 feet below land surface, the hole is cased to a depth of 82 feet and equipped with three piezometer tubes to depths of 592 feet, 968 feet, and 1,330 feet. A 5-foot well screen is at the bottom of each piezometer. Each screened interval has a cement plug above and below it to isolate it from other parts of the aquifer , and the well bore is filled between the plugs with sediment. Nine cores and 49 sidewall cores were recovered. Laboratory tests were made for mineralogy, hydraulic conductivity, porosity , consolidation, grain-size distribution, Atterberg limits, X-ray diffraction, and chemical quality of water. Geophysical and thermal gradient logs were made. The hole is sampled periodically for chemical analysis and measured for water level in the three tapped zones. This report presents methods used to obtain field samples, laboratory procedures, and the data obtained. (USGS)

  8. Results of test drilling in the Basalt aquifer near Fallon, Nevada

    USGS Publications Warehouse

    Maurer, Douglas K.

    2002-01-01

    Drilling of two test holes into the Fallon basalt aquifer commenced August 14, 2001. The basalt aquifer is located beneath the Carson Desert, near Fallon, Nevada, and is the sole source of drinking water for the City of Fallon, the Naval Air Station (NAS) Fallon, and the Fallon Paiute-Shoshone Tribe. Basalt comprising the aquifer is exposed at Rattlesnake Hill, an eroded volcanic cone, about 1 mile northeast of Fallon, and the remainder is buried beneath sediments deposited by the Carson River and ancient Lake Lahontan to depths of 600 feet near its edges (fig. 1). The basalt-aquifer system is a mushroom-shaped body of highly permeable volcanic rock. Viewed from above, the lateral extent of the basalt body is oval-shaped, about 4-miles wide and 10-miles long (fig. 1). Drilling was part of a cooperative study between the U.S. Geological Survey (USGS), the Bureau of Reclamation, and NAS Fallon. The study was started because of concern about the continued viability of the basalt-aquifer system as a source of municipal water supply. Increased pumping from about 1,700 acre-feet per year (acre-ft/yr) in the 1970?s to over 3,000 acre-ft/yr in the late 1990?s has caused water levels in the basalt to decline as much as 12 feet (fig. 2). During this same time period, water pumped from the aquifer at NAS Fallon and the City of Fallon wells showed that concentrations of dissolved chloride increased, although chloride concentrations were well within the U.S. Environmental Protection Agency?s (EPA) drinking-water standards; at this rate of increase, it would take decades to exceed the present standard (Maurer and Welch, 2001, p. 46). Concentrations of arsenic in the aquifer are about 0.1 milligrams per liter (mg/L), exceeding the drinking-water standard of 0.01 mg/L, but show no apparent change over time (Maurer and Welch, 2001, p. 10 and 48; U. S. Environmental Protection Agency, 2001). Increasing concentrations of chloride may be caused by increased pumping, that induces

  9. Nature and extent of lava-flow aquifers beneath Pahute Mesa, Nevada Test Site

    SciTech Connect

    Prothro, L.B.; Drellack, S.L. Jr.

    1997-09-01

    Work is currently underway within the Underground Test Area subproject of the US Department of Energy/Nevada Operations Office Environmental Restoration Program to develop corrective action plans in support of the overall corrective action strategy for the Nevada Test Site as established in the Federal Facility Agreement and Consent Order (FFACO, 1996). A closure plan is currently being developed for Pahute Mesa, which has been identified in the FFACO as consisting of the Western and Central Pahute Mesa Corrective Action Units. Part of this effort requires that hydrogeologic data be compiled for inclusion in a regional model that will be used to predict a contaminant boundary for these Corrective Action Units. Hydrogeologic maps have been prepared for use in the model to define the nature and extent of aquifers and confining units that might influence the flow of contaminated groundwater from underground nuclear tests conducted at Pahute Mesa. Much of the groundwater flow beneath Pahute Mesa occurs within lava-flow aquifers. An understanding of the distribution and hydraulic character of these important hydrogeologic units is necessary to accurately model groundwater flow beneath Pahute Mesa. This report summarizes the results of a study by Bechtel Nevada geologists to better define the hydrogeology of lava-flow aquifers at Pahute Mesa. The purpose of this study was twofold: (1) aid in the development of the hydrostratigraphic framework for Pahute Mesa, and (2) provide information on the distribution and hydraulic character of lava-flow aquifers beneath Pahute Mesa for more accurate computer modeling of the Western and Central Pahute Mesa Corrective Action Units.

  10. Are single-well "push-pull" tests suitable tracer methods for aquifer characterization?

    NASA Astrophysics Data System (ADS)

    Hebig, Klaus; Zeilfelder, Sarah; Ito, Narimitsu; Machida, Isao; Scheytt, Traugott; Marui, Atsunao

    2013-04-01

    Recently, investigations were conducted for geological and hydrogeological characterisation of the sedimentary coastal basin of Horonobe (Hokkaido, Japan). Coastal areas are typical geological settings in Japan, which are less tectonically active than the mountain ranges. In Asia, and especially in Japan, these areas are often densely populated. Therefore, it is important to investigate the behaviour of solutes in such unconsolidated aquifers. In such settings sometimes only single boreholes or groundwater monitoring wells are available for aquifer testing for various reasons, e.g. depths of more than 100 m below ground level and slow groundwater velocities due to density driven flow. A standard tracer test with several involved groundwater monitoring wells is generally very difficult or even not possible at these depths. One of the most important questions in our project was how we can obtain information about chemical and hydraulic properties in such aquifers. Is it possible to characterize solute transport behaviour parameters with only one available groundwater monitoring well or borehole? A so-called "push-pull" test may be one suitable method for aquifer testing with only one available access point. In a push-pull test a known amount of several solutes including a conservative tracer is injected into the aquifer ("push") and afterwards extracted ("pull"). The measured breakthrough curve during the pumping back phase can then be analysed. This method has already been used previously with various aims, also in the recent project (e.g. Hebig et al. 2011, Zeilfelder et al. 2012). However, different test setups produced different tracer breakthrough curves. As no systematic evaluation of this aquifer tracer test method was done so far, nothing is known about its repeatability. Does the injection and extraction rate influence the shape of the breakthrough curve? Which role plays the often applied "chaser", which is used to push the test solution out from the

  11. A field proof-of-concept of tomographic slug tests in an anisotropic littoral aquifer

    NASA Astrophysics Data System (ADS)

    Paradis, Daniel; Gloaguen, Erwan; Lefebvre, René; Giroux, Bernard

    2016-05-01

    Hydraulic tomography is increasingly recognized as a characterization approach that can image pathways or barriers to flow as well as their connectivity. In this study, we assess the performance of a transient analysis of tomographic slug test head data in estimating heterogeneity in horizontal hydraulic conductivity (Kh), hydraulic conductivity anisotropy (the ratio between vertical and horizontal hydraulic conductivity - Kv/Kh) and specific storage (Ss) under actual field conditions. The tomographic experiment was carried out between two wells in a moderately heterogeneous and highly anisotropic silt and sand littoral aquifer. In this field proof-of-concept, the inversion of the two-dimensional (2D) head dataset was computed with a 2D radial flow algorithm that considers Kh, Kv/Kh, Ss and wellbore storage effects. This study demonstrated that a transient analysis of tomographic slug tests is able to capture the key features of the littoral environment of the test: the vertical profiles of Kh and Kv are indeed in agreement with those from other field and laboratory tests, and Ss values exhibit physically plausible profiles. Furthermore, the simulation of independent inter-well hydraulic tests (slug and pumping tests screened over the entire aquifer) using resolved Kh, Kv/Kh and Ss tomograms produce responses very close to field observations. This study demonstrates that the effects of fine scale heterogeneity that induces K-anisotropy at larger scales can be captured through a transient analysis of tomographic slug tests, which are very difficult to quantify otherwise with conventional hydraulic tests, thus allowing a better representation of properties controlling flow and transport in aquifer systems.

  12. Analysis and interpretation of data obtained in tests of the geothermal aquifer at Klamath Falls, Oregon

    USGS Publications Warehouse

    Sammel, E.A.

    1984-01-01

    Water with temperatures to 130 C occurs in an extensive, heterogeneous aquifer at depths of a few hundred to nearly 2,000 feet. Chemical and isotopic analyses suggest that 190 C water mixes with cooler recharge water in a ratio of about 2 to 3 in zone within and beneath the aquifer. The water spreads from a fault zone and is tapped for space heating by more than 450 wells over a 2 square-mile area. Data obtained during a 50-day pumping and reinjection test in July and August, 1983, were fitted to theoretical double-porosity type curves. Predictions of water-level changes were made for two hypothetical pumping and reinjection schemes. It was determined that reinjection can generally offset declines due to pumping, although water levels will decline near pumped wells and will rise near injection wells. Tracer tests confirmed the double-porosity behavior of the aquifer. Discharge from thermal wells averages about 540 gallons per minute and heat discharge is about 18 x 10 to the 12th power British Thermal Units per year. Down-hole heat exchangers discharge about 13 x 10 to the 10th power British Thermal Units per year. Additional development probably is feasible. (USGS)

  13. WTAQ version 2-A computer program for analysis of aquifer tests in confined and water-table aquifers with alternative representations of drainage from the unsaturated zone

    USGS Publications Warehouse

    Barlow, Paul M.; Moench, Allen F.

    2011-01-01

    The computer program WTAQ simulates axial-symmetric flow to a well pumping from a confined or unconfined (water-table) aquifer. WTAQ calculates dimensionless or dimensional drawdowns that can be used with measured drawdown data from aquifer tests to estimate aquifer hydraulic properties. Version 2 of the program, which is described in this report, provides an alternative analytical representation of drainage to water-table aquifers from the unsaturated zone than that which was available in the initial versions of the code. The revised drainage model explicitly accounts for hydraulic characteristics of the unsaturated zone, specifically, the moisture retention and relative hydraulic conductivity of the soil. The revised program also retains the original conceptualizations of drainage from the unsaturated zone that were available with version 1 of the program to provide alternative approaches to simulate the drainage process. Version 2 of the program includes all other simulation capabilities of the first versions, including partial penetration of the pumped well and of observation wells and piezometers, well-bore storage and skin effects at the pumped well, and delayed drawdown response of observation wells and piezometers.

  14. Aquifer recharge with reclaimed water in the Llobregat Delta. Laboratory batch experiments and field test site.

    NASA Astrophysics Data System (ADS)

    Tobella, J.

    2010-05-01

    Summary Spain, as most other Mediterranean countries, faces near future water shortages, generalized pollution and loss of water dependent ecosystems. Aquifer recharge represents a promising option to become a source for indirect potable reuse purposes but presence of pathogens as well as organic and inorganic pollutants should be avoided. To this end, understanding the processes of biogeochemical degradation occurring within the aquifer during infiltration is capital. A set of laboratory batch experiments has been assembled in order to assess the behaviour of selected pesticides, drugs, estrogens, surfactant degradation products, biocides and phthalates under different redox conditions. Data collected during laboratory experiments and monitoring activities at the Sant Vicenç dels Horts test site will be used to build and calibrate a numerical model (i) of the physical-chemical-biochemical processes occurring in the batches and (ii) of multicomponent reactive transport in the unsaturated/saturated zone at the test site. Keywords Aquifer recharge, batch experiments, emerging micropollutants, infiltration, numerical model, reclaimed water, redox conditions, Soil Aquifer Treatment (SAT). 1. Introduction In Spain, the Llobregat River and aquifers, which supply water to Barcelona, have been overexploited for years and therefore, suffer from serious damages: the river dries up on summer, riparian vegetation has disappeared and seawater has intruded the aquifer. In a global context, solutions to water stress problems are urgently needed yet must be sustainable, economical and safe. Recent developments of analytical techniques detect the presence of the so-called "emerging" organic micropollutants in water and soils. Such compounds may affect living organisms when occurring in the environment at very low concentrations (microg/l or ng/l). In wastewater and drinking water treatment plants, a remarkable removal of these chemicals from water can be obtained only using

  15. Estimation of hectare-scale soil-moisture characteristics from aquifer-test data

    USGS Publications Warehouse

    Moench, A.F.

    2003-01-01

    Analysis of a 72-h, constant-rate aquifer test conducted in a coarse-grained and highly permeable, glacial outwash deposit on Cape Cod, Massachusetts revealed that drawdowns measured in 20 piezometers located at various depths below the water table and distances from the pumped well were significantly influenced by effects of drainage from the vadose zone. The influence was greatest in piezometers located close to the water table and diminished with increasing depth. The influence of the vadose zone was evident from a gap, in the intermediate-time zone, between measured drawdowns and drawdowns computed under the assumption that drainage from the vadose zone occurred instantaneously in response to a decline in the elevation of the water table. By means of an analytical model that was designed to account for time-varying drainage, simulated drawdowns could be closely fitted to measured drawdowns regardless of the piezometer locations. Because of the exceptional quality and quantity of the data and the relatively small aquifer heterogeneity, it was possible by inverse modeling to estimate all relevant aquifer parameters and a set of three empirical constants used in the upper-boundary condition to account for the dynamic drainage process. The empirical constants were used to define a one-dimensional (ID) drainage versus time curve that is assumed to be representative of the bulk material overlying the water table. The curve was inverted with a parameter estimation algorithm and a ID numerical model for variably saturated flow to obtain soil-moisture retention curves and unsaturated hydraulic conductivity relationships defined by the Brooks and Corey equations. Direct analysis of the aquifer-test data using a parameter estimation algorithm and a two-dimensional, axisymmetric numerical model for variably saturated flow yielded similar soil-moisture characteristics. Results suggest that hectare-scale soil-moisture characteristics are different from core-scale predictions

  16. Investigation on the Reciprocity Principle with In-Situ Pumping Test in Confined Aquifer

    NASA Astrophysics Data System (ADS)

    Chen, Yong-Lin; Lin, Hong-Ru; Huang, Shao-Yang; Yeh, Tian-Chyi J.; Wen, Jet-Chau

    2016-04-01

    In this study, the pumping test of reciprocity between wells is developed for 11 wells located on campus of NYUST. The reciprocity analysis is conducted with the heterogeneous hydraulic properties distributions of the site. The mathematical theory of reciprocity implies that choose one as stimulation point and the other as observed response point in two known points at the same random field. Repeat the above action, the response behavior should have the reciprocity between the two points. However, the lack of literature with the field experiment to prove that reciprocity principle. Therefore, this study is expected to investigate the reciprocity of drawdown with the pumping test which will have heterogeneous hydraulic properties distributions obtained by inverse process. In general, there are two ways to investigate the reciprocity of pumping tests of two wells. One way is to evaluate the drawdown reciprocity of two sequential wells. From the evaluation the reciprocity of the drawdown behavior during the sequential pumping wells, the reciprocity of the drawdown behavior is investigated. The other one is to estimate cross-correlation between the drawdown behavior of the sequential pumping wells and heterogeneous hydraulic properties distributions. The reciprocity of between the drawdown and the heterogeneous hydraulic properties distributions is therefore can be investigated. This study proved the reciprocity of drawdown with the sequential pumping test and heterogeneous hydraulic properties distributions obtained by inverse method. Meanwhile, we proved the reciprocity is existed during the pumping test in the confined aquifer. Keywords: Reciprocity, Cross-correlation, Confined aquifer, Stimulation, Response

  17. Evaluation of multi-well test data in a faulted aquifer using linear and radial flow models

    SciTech Connect

    Allen, D.M.; Michel, F.A.

    1998-11-01

    An extensive drilling and testing program was undertaken at Carleton University, Ottawa, Canada, to characterize the aquifer for the design of an aquifer thermal energy storage (ATES) system. The substantial data base provides an excellent record of well yields and hydraulic responses to a series of aquifer tests in a faulted carbonate aquifer. Well yield variability is reflected in the wide range in specific capacity and is dependent upon the proximity of a well to a major fault. Constant discharge data, available for nine pumping wells and several observation wells, reflect both the excellent hydraulic connection along major faults and the limited hydraulic connection between fault blocks. Three different flow models, including vertical fracture and vertical dyke (linear), and Theis (radial), are used to interpret constant discharge test data from nine pumping wells and several observation wells. In all tests, the duration of pumping is sufficient to identify early-time linear flow along faults and late-time pseudo-radial flow between fault blocks. This paper demonstrates the influence of fault-induced heterogeneity on the hydraulic response of a carbonate aquifer and demonstrates the application and limitation of simple radial continuum models to aquifers of this type.

  18. Aquifer characterisation using Surface NMR jointly with other geophysical techniques at the Nauen/Berlin test site

    NASA Astrophysics Data System (ADS)

    Yaramanci, Ugur; Lange, Gerhard; Hertrich, Marian

    2002-05-01

    The quite new technique of Surface Nuclear Magnetic Resonance (SNMR) has been extensively tested on the test site Nauen near Berlin to yield the geometry, water content and hydraulic conductivity of the aquifer. The test site is composed of an unconfined aquifer consisting of Quaternary sands with glacial till beneath. It is a very favourable site for assessing the suitability and performance of joint geophysical methods for groundwater exploration. Complementary measurements to SNMR were conducted with Ground Penetrating Radar (GPR), 1D-complex resistivity soundings, i.e. Spectral Induced Polarisation (SIP), 2D-geoelectrics and refraction seismics. Laboratory measurements of porosities, grain size distributions and Nuclear Magnetic Resonance (NMR) decay times were carried out on core samples, and hydraulic conductivities were also derived in order to control and interpret the results of field measurements. The SNMR method allowed the detection of the aquifer beyond any doubt and the determination of the approximate aquifer geometry. The aquifer water content found by SNMR fits very well with the independent measurements on core samples. Hydraulic conductivities derived from decay times are well in range with those from laboratory measurements. GPR allowed a very reliable determination of the aquifer geometry. This information, incorporated into inversion of geoelectric data, led to an improved determination of aquifer electrical resistivity. The estimation of water content by GPR and geoelectrics, even under the favourable conditions in Nauen, is by far not as reliable as that by SNMR. Obtaining information about hydraulic conductivity is possible only with SNMR. Thus, in combination with other geophysical methods, SNMR allows a much more detailed and reliable assessment of aquifers than what was possible with other surface geophysical methods before. In fact, it is, by far, the only method that allows direct detection of water and reliable estimations about water

  19. Data for ground-water test hole near Zamora, Central Valley Aquifer Project, California

    USGS Publications Warehouse

    French, J.J.; Page, R.W.; Bertoldi, G.L.

    1982-01-01

    Preliminary data are presented for the first of seven test holes drilled as a part of the Central Valley Aquifer Project which is part of the National Regional Aquifer Systems Analysis Program. The test hole was drilled in the SW 1/4 SE 1/4 sec. 34, T. 12 N. , R. 1 E., Yolo County, California, about 3 miles northeast of the town of Zamora. Drilled to a depth of 2,500 feet below land surface, the hole is cased to a depth of 190 feet and equipped with three piezometer tubes to depths of 947, 1,401, and 2,125 feet. A 5-foot well screen is at the bottom of each piezometer. Eighteen cores and 68 sidewall cores were recovered. Laboratory tests were made for mineralogy, hydraulic conductivity, porosity , consolidation, grain-size distribution, Atterberg limits, X-ray diffraction, diatom identification, thermal conductivity, and chemical analysis of water. Geophysical and thermal gradient logs were made. The hole is sampled periodically for chemical analysis and measured for water level in the three tapped zones. This report presents methods used to obtain field samples, laboratory procedures, and the data obtained. (USGS)

  20. Presence of Selected Methanogens, Fibrolytic Bacteria, and Proteobacteria in the Gastrointestinal Tract of Neonatal Dairy Calves from Birth to 72 Hours

    PubMed Central

    Guzman, Cesar E.; Bereza-Malcolm, Lara T.; De Groef, Bert; Franks, Ashley E.

    2015-01-01

    The microbial communities in the gastrointestinal tract of a young calf are essential for the anatomical and physiological development that permits a transition from milk to solid feed. Selected methanogens, fibrolytic bacteria, and proteobacteria were quantified in the rumen fluid and tissue, abomasum fluid, cecum fluid and tissue, and feces of Holstein bull calves on day 0 (0–20 mins after birth), day 1 (24 ± 1 h after birth), day 2 (48 ± 1 h after birth), and day 3 (72 ± 1 h after birth). Methanogens, fibrolytic bacteria, and Geobacter spp. were found to be already present from birth, indicating that microbial colonization of the gastrointestinal tract occurred before or during delivery. The abundance of methanogens and Geobacter spp. differed between the days tested and between compartments of the digestive tract and feces, but such difference was not observed for fibrolytic bacteria. Our findings suggests that methanogens might have an alternative hydrogen provider such as Geobacter spp. during these early stages of postnatal development. In addition, fibrolytic bacteria were present in the rumen well before the availability of fibrous substrates, suggesting that they might use nutrients other than cellulose and hemicellose. PMID:26186002

  1. Sensitivity and resolution of tomographic pumping tests in an alluvial aquifer

    USGS Publications Warehouse

    Bohling, G.C.

    2009-01-01

    Various investigators have proposed hydraulic tomography, the simultaneous analysis of responses to multiple well tests, as a means to obtain a high-resolution characterization of aquifer flow properties. This study assesses the information content of drawdown records from a set of tomographic pumping tests in an alluvial aquifer, comparing the parameter sensitivity and resolution associated with transient and steady-shape formulations of the objective function for the parameter estimation problem. The steady-shape approach takes advantage of the rapid establishment of constant gradients within the region surrounding a pumping well, comparing observed drawdown differences within this region with drawdown differences predicted by a steady state model. Both the transient and steady-shape approaches resolve K variations only within a limited distance of the pumping intervals and observation points. Relative to the transient approach, the steady-shape approach reduces the influence of poorly resolved property variations, including K variations outside the region of investigation and storage coefficient variations throughout the model domain. Copyright 2009 by the American Geophysical Union.

  2. High-resolution Electrical Resistivity Tomography monitoring of a tracer test in a confined aquifer

    NASA Astrophysics Data System (ADS)

    Wilkinson, P. B.; Meldrum, P. I.; Kuras, O.; Chambers, J. E.; Holyoake, S. J.; Ogilvy, R. D.

    2010-04-01

    A permanent geoelectrical subsurface imaging system has been installed at a contaminated land site to monitor changes in groundwater quality after the completion of a remediation programme. Since the resistivities of earth materials are sensitive to the presence of contaminants and their break-down products, 4-dimensional resistivity imaging can act as a surrogate monitoring technology for tracking and visualising changes in contaminant concentrations at much higher spatial and temporal resolution than manual intrusive investigations. The test site, a municipal car park built on a former gasworks, had been polluted by a range of polycyclic aromatic hydrocarbons and dissolved phase contaminants. It was designated statutory contaminated land under Part IIA of the UK Environmental Protection Act due to the risk of polluting an underlying minor aquifer. Resistivity monitoring zones were established on the boundaries of the site by installing vertical electrode arrays in purpose-drilled boreholes. After a year of monitoring data had been collected, a tracer test was performed to investigate groundwater flow velocity and to demonstrate rapid volumetric monitoring of natural attenuation processes. A saline tracer was injected into the confined aquifer, and its motion and evolution were visualised directly in high-resolution tomographic images in near real-time. Breakthrough curves were calculated from independent resistivity measurements, and the estimated seepage velocities from the monitoring images and the breakthrough curves were found to be in good agreement with each other and with estimates based on the piezometric gradient and assumed material parameters.

  3. Three-dimensional numerical analysis of steady state pumping tests in heterogeneous confined aquifers

    NASA Astrophysics Data System (ADS)

    Firmani, G.; Fiori, A.; Bellin, A.

    2006-03-01

    We study three-dimensional steady state flow field generated by a fully penetrating well extracting a constant water discharge from a confined aquifer of constant thickness. The hydraulic conductivity K is modeled as an axisymmetric, stationary random space function, and the flow equation is solved by using the seven-node finite volume numerical scheme. In view of application in aquifer characterization we analyze how the equivalent conductivity Keq varies as a function of the distance from the extraction well. The numerical simulations showed that the boundary condition at the well exerts a large impact on Keq and that the first-order solution in σY2 obtained by Indelman et al. (1996) is valid up to σY2 = 0.5. For higher values of σY2 the first-order solution overestimates Keq with differences that for a given σY2, reduce progressively as the formation becomes more anisotropic. A simple inverse procedure based on Keq, obtained through cross-well interference, is finally proposed and tested with the objective of estimating the parameters of the geostatistical model of variability of the hydraulic conductivity. A few parametric examples showed that a suitable interpretation of pumping tests can be used to safely estimate parameters such as the geometric mean of the hydraulic conductivity, its variance, and, although with larger uncertainty, the horizontal integral scale, while the inference of the anisotropy ratio is highly uncertain and error prone.

  4. Experimental studies in stream-aquifer interaction along the Arkansas River in Central Kansas - Field testing and analysis

    USGS Publications Warehouse

    Sophocleous, M.; Townsend, M.A.; Vogler, L.D.; McClain, T.J.; Marks, E.T.; Coble, G.R.

    1988-01-01

    During the last several years, streamflows of a number of Kansas streams have been reduced as a result of groundwater declines. In order to better understand and quantify stream-aquifer interrelationships, an eight-day comprehensive stream-aquifer pumping test, followed by recovery monitoring, was conducted along the Arkansas River near Great Bend, Kansas. In addition to water level monitoring in numerous observation wells, streamflow data, streambed hydraulic gradients, neutron probe-based water content of dewatered sediments, water chemistry and other data were collected. The alluvial aquifer is shown to be highly transmissive (T = 1803 m2d-1) with the pumping stress (9538 m3d-1) having a radius of influence larger than 1.77 km, impacting both the aquifer levels and the streamflow in the nearby Arkansas River. Drawdown and recharge boundary effects were observed in all observation wells, including those on the opposite side of the river. The alluvial aquifer did not exhibit a water table behavior and responded as a leaky confined aquifer. A semiconfining clay layer less than 3 m thick and an additional recharge source from a nearby stream-alluvial system were the probable causes of the observed phenomena. Actual streamflow depletion is shown to be appreciably less than the computed depletion based on analytical solutions. ?? 1988.

  5. Hydrologic properties of coal-beds in the Powder River Basin, Montana. II. Aquifer test analysis

    USGS Publications Warehouse

    Weeks, E.P.

    2005-01-01

    A multiple well aquifer test to determine anisotropic transmissivity was conducted on a coal-bed in the Powder River Basin, southeastern Montana, as part of a multidisciplinary investigation to determine hydrologic conditions of coal-beds in the area. For the test, three wells were drilled equidistant from and at different angles to a production well tapping the Flowers-Goodale coal seam, a 7.6-m thick seam confined at a depth of about 110 m. The test was conducted by air-lift pumping for 9 h, and water levels were monitored in the three observation wells using pressure transducers. Drawdown data collected early in the test were affected by interporosity flow between the coal fracture network and the matrix, but later data were suitable to determine aquifer anisotropy, as the slopes of the late-time semilog time-drawdown curves are nearly identical, and the zero-drawdown intercepts are different. The maximum transmissivity, trending N87??E, is 14.9 m2/d, and the minimum transmissivity 6.8 m2/d, giving an anisotropy ratio of 2.2:1. Combined specific storage of the fractures and matrix is 2??10 -5/m, and of the fracture network alone 5??10-6/m. The principal direction of the anisotropy tensor is not aligned with the face cleats, but instead is aligned with another fracture set and with dominant east-west tectonic compression. Results of the test indicate that the Flowers-Goodale coal-bed is more permeable than many coals in the Powder River Basin, but the anisotropy ratio and specific storage are similar to those found for other coal-beds in the basin.

  6. Assessment of a Geothermal Doublet in the Malm Aquifer Using a Push-Pull Tracer Test

    NASA Astrophysics Data System (ADS)

    Lafogler, Mark; Somogyi, Gabriella; Nießner, Reinhard; Baumann, Thomas

    2013-04-01

    Geothermal exploration of the Malm aquifer in Bavaria is highly successful. Data about the long-term operation, however, is still scarce, although detailed knowledge about the processes occurring in the aquifer is a key requirement to run geothermal facilities efficiently and economically. While there usually is a constant flow of data from the production well (temperatures, hydraulic data, hydrochemical conditions, gas composition) not even the temperatures in the immediate surrounding of the reinjection well are accessible or known. In 2011 the geothermal facility in Pullach was extended with a third geothermal well reaching into the Malm aquifer which is now used as a reinjection well. The former reinjection well was converted to a production well after 5 years of operation. This setting offers a unique opportunity to study the processes in the vicinity of a reinjection well and provides the data base to describe the hydraulic, thermal and hydrochemical performance of the reservoir. The viscosity of the reinjected cold water is increasing by 60% compared to the production well, thus one would expect an increase of the reinjection pressure as the cold water plume spreads around the reinjection well. Measurements, however, show a significant decrease of the reinjection pressure, suggesting processes in the aquifer which positively change the hydraulic properties and overcompensate the viscosity effects. Hydrochemical data and modeling indicate that a dissolution of the matrix along the flow pathways is responsible for the decreasing reinjection pressures. The change of the flow direction from reinjection to production was used to conduct a push-pull tracer test. Here, a series of fluorescent dye pulses was added to the reinjected water before the former reinjection well was shut down (push phase). These tracers included a conservative tracer (Fluorescein), surface-sensitive tracers (Eosin/Sulforhodamin B), and a NAPL-sensitive tracer (Na-Naphthionate). After

  7. Analytical results of a long-term aquifer test conducted near the Rio Grande, Albuquerque, New Mexico, with a section on piezometric-extensometric test results

    USGS Publications Warehouse

    Thorn, Conde R.; Heywood, Charles E.

    2001-01-01

    The City of Albuquerque, New Mexico, is interested in gaining a better understanding, both quantitative and qualitative, of the aquifer system in and around Albuquerque. Currently (2000), the City of Albuquerque and surrounding municipalities are completely dependent on ground-water reserves for their municipal water supply. This report presents the results of a long-term aquifer test conducted near the Rio Grande in Albuquerque. The long-term aquifer test was conducted during the winter of 1994-95. The City of Albuquerque Griegos 1 water production well was pumped continuously for 54 days at an average pumping rate of 2,331 gallons per minute. During the 54-day pumping and a 30-day recovery period, water levels were recorded in a monitoring network that consisted of 3 production wells and 19 piezometers located at nine sites. These wells and piezometers were screened in river alluvium and (or) the upper and middle parts of the Santa Fe Group aquifer system. In addition to the measurement of water levels, aquifer-system compaction was monitored during the aquifer test by an extensometer. Well-bore video and flowmeter surveys were conducted in the Griegos 1 water production well at the end of the recovery period to identify the location of primary water- producing zones along the screened interval. Analytical results from the aquifer test presented in this report are based on the methods used to analyze a leaky confined aquifer system and were performed using the computer software package AQTESOLV. Estimated transmissivities for the Griegos 1 and 4 water production wells ranged from 10,570 to 24,810 feet squared per day; the storage coefficient for the Griegos 4 well was 0.0025. A transmissivity of 13,540 feet squared per day and a storage coefficient of 0.0011 were estimated from the data collected from a piezometer completed in the production interval of the Griegos 1 well.

  8. Analysis of Responses From Hydraulic Testing of the Lower Carbonate Aquifer at Yucca Flat, Nevada Test Site, Nye County, Nevada

    NASA Astrophysics Data System (ADS)

    Bhark, E. W.; Ruskauff, G.

    2005-12-01

    The Yucca Flat corrective action unit extends over an approximately 120 square-mile basin at the Nevada Test Site (NTS), southern Nevada, and was the site for over 650 historical underground nuclear tests. The lower carbonate aquifer (LCA), roughly 1,800 feet below ground surface at Yucca Flat and with a confined thickness of several thousand feet, is the primary aquifer for much of southern Nevada and underlies the full extent of Yucca Flat. Within the last decade, long-term (multiple-day) single- and multiple-well hydraulic tests have been performed to better define aquifer properties over larger scales. The LCA is highly heterogeneous, both laterally and vertically across Yucca Flat, reflecting differences in fracturing and fault density. As such, analysis of the recent testing data requires the consideration of heterogeneous hydraulic properties at multiple spatial scales. Three individual hydraulic tests are presented that portray the marked spatial variability of hydraulic properties related to both local fracturing and basin-scale faulting across Yucca Flat. Two ten-day single-well tests (wells ER-7-1, ER-6-2) and one ninety-day multiple-well test (well cluster ER-6-1) are considered. Interpretive and numerical analyses are based upon the log-log diagnostic plots of drawdown and recovery from pumping, utilizing both the head change and derivative. Heterogeneity is considered using the flow dimension, which represents a variable formation area of flow away from the well, and proves to be a fundamental analytical tool. All hydraulic parameter estimates, including flow dimension, are complete with a measure of uncertainty. The composite interpretation of all data results in a conceptual flow model representative of two spatially continuous scales. At the larger basin (km) scale, the data indicate a fracture- or high permeability strip-dominated flow regime created by fault-related features. Ubiquitous north-south trending faults throughout Yucca Flat appear to

  9. Fractured rock aquifer tests in the Western Siberian Basin, Ozyorsk, Russia

    SciTech Connect

    Nichols, R.L.; Looney, B.B.; Eddy-Dilek, C.A.

    1997-10-01

    A series of multi-zone pumping tests was conducted in a contaminated fractured rock aquifer in the Western Siberian Basin, Ozyorsk, Russia. The tests were conducted adjacent to the Mishelyak River floodplain in fractured Paleozoic porphyrites, tufts, tuff breccia, and lava typical of the Ural mountain complex. Geophysical logs, borehole photography, core samples, and results from previous borehole contamination studies were used to identify the zones to be tested. A network of three uncased wells was tested using a system of inflatable packers, pressure transducers and data loggers. Seven zones were isolated and monitored in two of the uncased wells. A straddle packer assembly was used to isolate individual zones within the pumping well. Eight constant rate pumping tests were conducted. Results of the testing indicate that shallow groundwater migrates primarily in two intervals that are separated by an interval with low lateral conductivity. The water bearing intervals have moderate to high specific capacities (1.3 and 30 L/min/m). Several processes are responsible for fracturing present in the lower interval. The network of compound fractures produced a complex array of fracture intersections yielding a fractured media with hydraulic behavior similar to porous media. Models used for the analysis of pumping tests in porous media provide a good estimation of the hydraulic response of the lower interval to pumping. Future work will include more complex analysis of the data to determine hydraulic conductivity ellipses.

  10. Testing alternative conceptual models of seawater intrusion in a coastal aquifer using computer simulation, southern California, USA

    USGS Publications Warehouse

    Nishikawa, T.

    1997-01-01

    Two alternative conceptual models of the physical processes controlling seawater intrusion in a coastal basin in California, USA, were tested to identify a likely principal pathway for seawater intrusion. The conceptual models were tested by using a two-dimensional, finite-element groundwater flow and transport model. This pathway was identified by the conceptual model that best replicated the historical data. The numerical model was applied in cross section to a submarine canyon that is a main avenue for seawater to enter the aquifer system underlying the study area. Both models are characterized by a heterogeneous, layered, water-bearing aquifer. However, the first model is characterized by flat-lying aquifer layers and by a high value of hydraulic conductivity in the basal aquifer layer, which is thought to be a principal conduit for seawater intrusion. The second model is characterized by offshore folding, which was modeled as a very nearshore outcrop, thereby providing a shorter path for seawater to intrude. General conclusions are that: 1) the aquifer system is best modeled as a flat, heterogeneous, layered system; 2) relatively thin basal layers with relatively high values of hydraulic conductivity are the principal pathways for seawater intrusion; and 3) continuous clay layers of low hydraulic conductivity play an important role in controlling the movement of seawater.

  11. Aquifer tests at the Jackpile-Paguate uranium mine, Pueblo of Laguna, west-central New Mexico

    USGS Publications Warehouse

    Risser, D.W.; Davis, P.A.; Baldwin, J.A.; McaAda, D.P.

    1984-01-01

    The transmissivity of the Jackpile sandstone bed in the Brushy Basin Shale Member of the Morrison Formation, west-central New Mexico, was determined to be 24 sq ft/day at well M2 and 47 sq ft/day at well M3 from constant-discharge aquifer tests conducted at the Jackpile-Paguate Uranium Mine. The storage coefficient of the Jackpile sandstone bed was estimated to be 0.00018 at well M2 and 0.00029 at well M3 from the same tests. An aquifer test conducted at well M21 indicated the transmissivity of the Jackpile sandstone bed was 2.0 sq ft/day and the storage coefficient was 0.00002. The transmissivity of an unnamed sandstone bed in the Brushy Basin Shale Member of the Morrison Formation was estimated from ' slug-test ' results to be about 20 sq ft/day. Water levels in this sandstone probably did not change due to pumping from the overlying Jackpile sandstone bed for 88 hours at an average discharge of 15.3 gallons/min. A constant discharge aquifer test at well M4C indicated that the transmissivity of the alluvium at this location was about 430 sq ft/day. Water levels in the underlying Jackpile sandstone bed began declining within 15 minutes after withdrawals of groundwater from the alluvial aquifer began. (USGS)

  12. Hydrologic and water-chemistry data from the Cretaceous-aquifers test well (BFT-2055), Beaufort County, South Carolina

    USGS Publications Warehouse

    Landmeyer, J.E.; Bradley, P.M.

    1998-01-01

    Test well BFT-2055 was drilled through the entire thickness of Coastal Plain sediments beneath central Hilton Head Island, South Carolina, and terminated in bedrock at a depth of 3833 feet. The well was drilled to evaluate the hydraulic properties of the Cretaceous formations beneath Hilton Head Island as a potential source of supplemental water to supplies currently withdrawn from the Upper Floridan aquifer. The intervals tested include sediments of the Cape Fear and Middendorf Formations. Results from aquifer tests indicate that the transmissivity of the formations screened ranges from 1300 to 3000 feet squared per day and an average hydraulic conductivity of about 15 feet per day. Formation-fluid pressure tests indicate that the potential exists for upward ground-water flow from higher fluid pressures in the deeper Cape Fear and Middendorf Formations to lower fluid pressures in the Black Creek Formation and shallower units. A flowmeter test indicated that greater than 75 percent of the natural, unpumped flow in the well is from the screened intervals no deeper than 3100 feet. Water-chemistry analyses indicate that the water sampled from the Middendorf and Cape Fear has about 1450 milligrams per liter dissolved solids, 310 to 1000 milligrams per liter sodium, and 144 to 1600 milligrams per liter chloride. Because these chloride concentrations would render water pumped from these aquifers as nonpotable, it is unlikely that these aquifers will be used as a supplemental source of water for island residents without some form of pretreatment. Similar chloride concentrations are present in some wells in the Upper Floridan aquifer adjacent to Port Royal Sound, and these chloride concentrations were the primary reason for drilling the test well in the Cretaceous formations as a possible source of more potable water.

  13. Analytical and numerical analyses of an unconfined aquifer test considering unsaturated zone characteristics

    USGS Publications Warehouse

    Moench, A.F.

    2008-01-01

    A 7-d, constant rate aquifer test conducted by University of Waterloo researchers at Canadian Forces Base Borden in Ontario, Canada, is useful for advancing understanding of fluid flow processes in response to pumping from an unconfined aquifer. Measured data include not only drawdown in the saturated zone but also volumetric soil moisture measured at various times and distances from the pumped well. Analytical analyses were conducted with the model published in 2001 by Moench and colleagues, which allows for gradual drainage but does not include unsaturated zone characteristics, and the model published in 2006 by Mathias and Butler, which assumes that moisture retention and relative hydraulic conductivity (RHC) in the unsaturated zone are exponential functions of pressure head. Parameters estimated with either model yield good matches between measured and simulated drawdowns in piezometers. Numerical analyses were conducted with two versions of VS2DT: one that uses traditional Brooks and Corey functional relations and one that uses a RHC function introduced in 2001 by Assouline that includes an additional parameter that accounts for soil structure and texture. The analytical model of Mathias and Butler and numerical model of VS2DT with the Assouline model both show that the RHC function must contain a fitting parameter that is different from that used in the moisture retention function. Results show the influence of field-scale heterogeneity and suggest that the RHC at the Borden site declines more rapidly with elevation above the top of the capillary fringe than would be expected if the parameters were to reflect local- or core-scale soil structure and texture.

  14. Construction, Geology, and Aquifer Testing of the Maalo Road, Aahoaka Hill, and Upper Eleele Tank Monitor Wells, Kauai, Hawaii

    USGS Publications Warehouse

    Izuka, Scot K.

    2005-01-01

    The Maalo Road, Aahoaka Hill, and Upper Eleele Tank monitor wells were constructed using rotary drilling methods between July 1998 and August 2002 as part of a program of exploratory drilling, aquifer testing, and hydrologic analysis on Kauai. Aquifer tests were conducted in the uncased boreholes of the wells. The Maalo Road monitor well in the Lihue Basin penetrated 915 feet, mostly through mafic lava flows. Most of the rock samples from this well had chemical compositions similar to the Koloa Volcanics, but the deepest sample analyzed had a composition similar to the Waimea Canyon Basalt. Water temperature ranged from 25.6 to 27.4 degrees Celsius and specific conductance ranged from 303 to 627 microsiemens per centimeter during aquifer testing. Discharge rate ranged from 174 to 220 gallons per minute and maximum drawdown was 138.25 ft during a 7-day sustained-discharge test, but the test was affected by pump and generator problems. The Aahoaka Hill monitor well in the Lihue Basin penetrated 804 feet, mostly through mafic lava flows and possibly dikes. The well penetrated rocks having chemical compositions similar to the Waimea Canyon Basalt. During the first three hours of a sustained-discharge aquifer test in which the discharge rate varied between 92 and 117 gallons per minute, water temperature was 24.6 to 25.6 degrees Celsius, and specific conductance was 212 to 238 microsiemens per centimeter; this test was halted after a short period because drawdown was high. In a subsequent 7-day test, discharge was 8 to 23 gallons per minute, and maximum drawdown was 37.71 feet after 1,515 minutes of testing. The Upper Eleele Tank monitor well is near the Hanapepe River Valley. The well penetrated 740 feet through soil, sediment, mafic lava flows, volcanic ash, and scoria. Rocks above a depth of 345 feet had compositions similar to the Koloa Volcanics, but a sample from 720 to 725 feet had a composition similar to rocks of the Waimea Canyon Basalt. During a 7-day aquifer

  15. Development of in-aquifer heat testing for high resolution subsurface thermal-storage capability characterisation

    NASA Astrophysics Data System (ADS)

    Seibertz, Klodwig Suibert Oskar; Chirila, Marian Andrei; Bumberger, Jan; Dietrich, Peter; Vienken, Thomas

    2016-03-01

    The ongoing transition from fossil fuels to alternative energy source provision has resulted in increased geothermal uses as well as storage of the shallow subsurface. Existing approaches for exploration of shallow subsurface geothermal energy storage often lack the ability to provide information concerning the spatial variability of thermal storage parameters. However, parameter distributions have to be known to ensure that sustainable geothermal use of the shallow subsurface can take place - especially when it is subject to intensive usage. In this paper, we test a temperature decay time approach to obtain in situ, direct, qualitative, spatial high-resolution information about the distribution of thermal storage capabilities of the shallow subsurface. To achieve this, temperature data from a high-resolution Fibre-Optic-Distributed-Temperature-Sensing device, as well as data from conventional Pt100-temperature-sensors were collected during a heat injection test. The latter test was used to measure the decay time of temperature signal dissipation of the subsurface. Signal generation was provided by in-aquifer heating with a temperature self-regulating electric heating cable. Heating was carried out for 4.5 days. After this, a cooling period of 1.5 weeks was observed. Temperature dissipation data was also compared to Direct-Push-derived high-resolution (hydro-)geological data. The results show that besides hydraulic properties also the bedding and compaction state of the sediment have an impact on the thermal storage capability of the saturated subsurface. The temperature decay time approach is therefore a reliable method for obtaining information regarding the qualitative heat storage capability of heterogeneous aquifers for the use with closed loop system geothermal storage systems. Furthermore, this approach is advantageous over other commonly used methods, e.g. soil-sampling and laboratory analysis, as even small changes in (hydro-)geological properties lead to

  16. Three-Dimensional Bayesian Geostatistical Aquifer Characterization at the Hanford 300 Area using Tracer Test Data

    SciTech Connect

    Chen, Xingyuan; Murakami, Haruko; Hahn, Melanie S.; Hammond, Glenn E.; Rockhold, Mark L.; Zachara, John M.; Rubin, Yoram

    2012-06-01

    Tracer testing under natural or forced gradient flow holds the potential to provide useful information for characterizing subsurface properties, through monitoring, modeling and interpretation of the tracer plume migration in an aquifer. Non-reactive tracer experiments were conducted at the Hanford 300 Area, along with constant-rate injection tests and electromagnetic borehole flowmeter (EBF) profiling. A Bayesian data assimilation technique, the method of anchored distributions (MAD) [Rubin et al., 2010], was applied to assimilate the experimental tracer test data with the other types of data and to infer the three-dimensional heterogeneous structure of the hydraulic conductivity in the saturated zone of the Hanford formation. In this study, the Bayesian prior information on the underlying random hydraulic conductivity field was obtained from previous field characterization efforts using the constant-rate injection tests and the EBF data. The posterior distribution of the conductivity field was obtained by further conditioning the field on the temporal moments of tracer breakthrough curves at various observation wells. MAD was implemented with the massively-parallel three-dimensional flow and transport code PFLOTRAN to cope with the highly transient flow boundary conditions at the site and to meet the computational demands of MAD. A synthetic study proved that the proposed method could effectively invert tracer test data to capture the essential spatial heterogeneity of the three-dimensional hydraulic conductivity field. Application of MAD to actual field data shows that the hydrogeological model, when conditioned on the tracer test data, can reproduce the tracer transport behavior better than the field characterized without the tracer test data. This study successfully demonstrates that MAD can sequentially assimilate multi-scale multi-type field data through a consistent Bayesian framework.

  17. New methodology to investigate potential contaminant mass fluxes at the stream-aquifer interface by combining integral pumping tests and streambed temperatures.

    PubMed

    Kalbus, E; Schmidt, C; Bayer-Raich, M; Leschik, S; Reinstorf, F; Balcke, G U; Schirmer, M

    2007-08-01

    The spatial pattern and magnitude of mass fluxes at the stream-aquifer interface have important implications for the fate and transport of contaminants in river basins. Integral pumping tests were performed to quantify average concentrations of chlorinated benzenes in an unconfined aquifer partially penetrated by a stream. Four pumping wells were operated simultaneously for a time period of 5 days and sampled for contaminant concentrations. Streambed temperatures were mapped at multiple depths along a 60m long stream reach to identify the spatial patterns of groundwater discharge and to quantify water fluxes at the stream-aquifer interface. The combined interpretation of the results showed average potential contaminant mass fluxes from the aquifer to the stream of 272microgm(-2)d(-1) MCB and 71microgm(-2)d(-1) DCB, respectively. This methodology combines a large-scale assessment of aquifer contamination with a high-resolution survey of groundwater discharge zones to estimate contaminant mass fluxes between aquifer and stream.

  18. Microbial Stimulation and Succession following a Test Well Injection Simulating CO₂ Leakage into a Shallow Newark Basin Aquifer

    PubMed Central

    O’Mullan, Gregory; Dueker, M. Elias; Clauson, Kale; Yang, Qiang; Umemoto, Kelsey; Zakharova, Natalia; Matter, Juerg; Stute, Martin; Takahashi, Taro; Goldberg, David

    2015-01-01

    In addition to efforts aimed at reducing anthropogenic production of greenhouse gases, geological storage of CO2 is being explored as a strategy to reduce atmospheric greenhouse gas emission and mitigate climate change. Previous studies of the deep subsurface in North America have not fully considered the potential negative effects of CO2 leakage into shallow drinking water aquifers, especially from a microbiological perspective. A test well in the Newark Rift Basin was utilized in two field experiments to investigate patterns of microbial succession following injection of CO2-saturated water into an isolated aquifer interval, simulating a CO2 leakage scenario. A decrease in pH following injection of CO2 saturated aquifer water was accompanied by mobilization of trace elements (e.g. Fe and Mn), and increased bacterial cell concentrations in the recovered water. 16S ribosomal RNA gene sequence libraries from samples collected before and after the test well injection were compared to link variability in geochemistry to changes in aquifer microbiology. Significant changes in microbial composition, compared to background conditions, were found following the test well injections, including a decrease in Proteobacteria, and an increased presence of Firmicutes, Verrucomicrobia and microbial taxa often noted to be associated with iron and sulfate reduction. The concurrence of increased microbial cell concentrations and rapid microbial community succession indicate significant changes in aquifer microbial communities immediately following the experimental CO2 leakage event. Samples collected one year post-injection were similar in cell number to the original background condition and community composition, although not identical, began to revert toward the pre-injection condition, indicating microbial resilience following a leakage disturbance. This study provides a first glimpse into the in situ successional response of microbial communities to CO2 leakage after subsurface

  19. A controlled in situ field evaluation of a new dynamic vacuum slug test method in unconfined aquifers

    SciTech Connect

    Lauctes, B.A.; Schleyer, C.A.

    1995-09-01

    Most ground water site characterizations require initial estimates of the ground water flow velocity and potential downgradient extent of ground water contamination. The fundamental aquifer property, hydraulic conductivity, must be determined to make these essential estimates. Highly contaminated ground water often precludes conducting multi-well aquifer tests to evaluate hydraulic conductivity due to potential human health risks and ground water storage/treatment/disposal costs and logistics. Consequently, single-well slug tests are often sued, but the widely used pressure slug test method is not suitable for water table monitoring wells. As a result, a new slug test method was developed by GCL for unconfined aquifers. The new method was benchmarked against the widely used solid slug test method in a series of rising-head and falling-head slug tests. A statistical evaluation indicated no statistical difference (alpha = 0.05) between hydraulic conductivity values calculated from each method. The new dynamic vacuum method, designed specifically for use in water table monitoring wells, uses a continuous vacuum to draw air through the well screen exposed above the water table. The vacuum induces upwelling as air pressure inside the well casing drops below atmospheric pressure. Once upwelling equilibrates with the applied vacuum, the vacuum is released allowing the water to recover and the air pressure inside the casing to return to atmospheric pressure.

  20. Evaluation of longitudinal dispersivity estimates from simulated forced- and natural-gradient tracer tests in heterogeneous aquifers

    USGS Publications Warehouse

    Tiedeman, C.R.; Hsieh, P.A.

    2004-01-01

    We simulate three types of forced-gradient tracer tests (converging radial flow, unequal strength two well, and equal strength two well) and natural-gradient tracer tests in multiple realizations of heterogeneous two-dimensional aquifers with a hydraulic conductivity distribution characterized by a spherical variogram. We determine longitudinal dispersivities (??L) by analysis of forced-gradient test breakthrough curves at the pumped well and by spatial moment analysis of tracer concentrations during the natural-gradient tests. Results show that among the forced-gradient tests, a converging radial-flow test tends to yield the smallest ??L, an equal strength two-well test tends to yield the largest ??L, and an unequal strength two-well test tends to yield an intermediate value. This finding is qualitatively explained by considering the aquifer area sampled by a particular test. A converging radial-flow test samples a small area, and thus the tracer undergoes a low degree of spreading and mixing. An equal strength two-well test samples a much larger area, so the tracer is spread and mixed to a greater degree. Results also suggest that if the distance between the tracer source well and the pumped well is short relative to the lengths over which velocity is correlated, then the ??L estimate can be highly dependent on local heterogeneities in the vicinity of the wells. Finally, results indicate that ??L estimated from forced-gradient tracer tests can significantly underestimate the ??L needed to characterize solute dispersion under natural-gradient flow. Only a two-well tracer test with a large well separation in an aquifer with a low degree of heterogeneity can yield a value of ??L that characterizes natural-gradient tracer spreading. This suggests that a two-well test with a large well separation is the preferred forced-gradient test for characterizing solute dispersion under natural-gradient flow.

  1. Tests for injecting, storing, and recovering freshwater in a saline artesian aquifer, Lee County, Florida

    USGS Publications Warehouse

    Fitzpatrick, D.J.

    1986-01-01

    An investigation was made of the suitability of a saline, artesian limestone aquifer for the injection, storage, and recovery of freshwater from the Caloosahatchee River. The tests were conducted on a well tapping a leaky artesian system that has a transmissivity of 800 square feet per day, a storage of 1 x 10-4, and a leakance of 0.01 per day. The specific capacity of the injection well was increased through acidizing and was decreased as a result of well clogging during injection. Three injection tests were made wherein the amounts of freshwater injected, the storage duration, and the quality of water injected varied. Analysis of the test data showed that freshwater recoverability ranged from 9.7 to 38.7 percent of the total injected. Differences were attributed principally to differences in the quality of water injected and storage duration. Repeated injection-recovery cycles probably would result in greater recoverability. Head buildup, nearly 200 feet in one test, was a prime problem related chiefly to clogging from suspended material in the injected water and to bacterial growth at the wellbore-limestone interface. Regular backflushing was required. Total head buildup decreased as a result of acidizing the injection well. No coliforms or fecal streptococcus were noted in the recovered water. Growth of anaerobic bacteria occurred. Changes in the quality of the recovered water included decreases in concentration of dissolved organic carbon by as much as 15 mg/L (milligrams per liter), organic nitrogen by as much as 0.80 mg/L, and nitrate by as much as 0.50 mg/L. Increases were noted in ammonia by 0.40 mg/L, and iron by as much as 0.60 mg/L. These changes are consistent with the presence of an anaerobic bacterial ecosystem.

  2. Groundwater levels and water quality during a 96-hour aquifer test in Pickaway County, Ohio, 2012

    USGS Publications Warehouse

    Haefner, Ralph J.; Runkle, Donna L.; Mailot, Brian E.

    2014-01-01

    During October–November 2012, a 96-hour aquifer test was performed at a proposed well field in northern Pickaway County, Ohio, to investigate groundwater with elevated nitrate concentrations. Earlier sampling done by the City of Columbus revealed that some wells had concentrations of nitrate that approached 10 milligrams per liter (mg/L), whereas other wells and the nearby Scioto River had concentrations from 2 to 6 mg/L. The purpose of the current test was to examine potential changes in water quality that may be expected if the site was developed into a public water-supply source; therefore, water-transmitting properties determined during a previous test were not determined a second time. Before and during the test, water-level data and water-quality samples were obtained from observation wells while a test production well was pumped at 1,300 gallons per minute. Before the test, local groundwater levels indicated that groundwater was being discharged to the nearby Scioto River, but during the test, the stream was losing streamflow owing to infiltration. Water levels declined in the pumping well, in adjacent observation wells, and in a nearby streambed piezometer as pumping commenced. The maximum drawdown in the pumping well was 29.75 feet, measured about 95 hours after pumping began. Water-quality data, including analyses for field parameters, major and trace elements, nutrients, and stable isotopes of oxygen and nitrogen in nitrate, demonstrated only small variations before and during the test. Concentrations of nitrate in five samples from the pumping well ranged from about 5.10 to 5.42 mg/L before and during the test, whereas concentrations of nitrate in five samples on or about the same sampling dates and times at a monitoring site on the Scioto River adjacent to the pumping well ranged from 3.46 to 4.97 mg/L. Water from two nearby observation wells had nitrate concentrations approaching 10 mg/L, which is the U.S. Environmental Protection Agency’s Maximum

  3. Hydraulic characterization of aquifers by thermal response testing: Validation by large-scale tank and field experiments

    NASA Astrophysics Data System (ADS)

    Wagner, Valentin; Bayer, Peter; Bisch, Gerhard; Kübert, Markus; Blum, Philipp

    2014-01-01

    Thermal response tests (TRTs) are a common field method in shallow geothermics to estimate thermal properties of the ground. During the test, a constantly heated fluid is circulated in closed tubes within a vertical borehole heat exchanger (BHE). The observed temperature development of the fluid is characteristic for the thermal properties of the ground and the BHE. We show that, when the BHE is installed in an aquifer with significant horizontal groundwater flow, this test can also be used for hydrogeological characterization of the penetrated subsurface. An evaluation method based on the moving line source equation and considering the natural occurring variability of the thermal transport parameters is presented. It is validated by application to a well-controlled, large-scale tank experiment with 9 m length, 6 m width, and 4.5 m depth, and by data interpretation from a field-scale test. The tank experiment imitates an advection-influenced TRT in a well-known layered aquifer. The field experiment was recorded with a 100 m deep BHE, installed in a gravel aquifer in southwest Germany. The evaluations of both experiments result in similar hydraulic conductivity ranges as determined by standard hydraulic investigation methods such as pumping tests and sieve analyses. Thus, advection-influenced TRTs could also potentially be used to determine integral hydraulic conductivity of the subsurface.

  4. Hydrogeology of the Leadville limestone and other paleozoic rocks in northwestern Colorado, with results of aquifer tests at Glenwood Springs

    USGS Publications Warehouse

    Geldon, Arthur L.

    1989-01-01

    Paleozoic rocks in northwestern Colorado were investigated during the U.S. Geological Survey 's Regional Aquifer Systems Analysis of the Upper Colorado River Basin. Paleozoic rocks in the study area are grouped into 11 hydrostratigraphic units on the basis of lithologic and hydrologic properties. Devonian and Mississippian carbonate rocks and Pennsylvanian and Permian sandstone are regional aquifers, with natural discharges commonly ranging from 50 to 1,000 gal/min. Other hydrostratigraphic units in the area are either local aquifers or confining layers, with discharges rarely exceeding 50 gal/min. Aquifer tests at Glenwood Springs indicate that the Devonian and Mississippian carbonate rocks unit locally has a transmissivity of 47,000 sq ft/day, a storage coefficient of 0.0005, and a hydraulic conductivity of more than 100 ft/day. Hydraulic conductivities in most hydrostratigraphic units decrease with distance away from structural uplifts. Water in the Devonian and Mississippian carbonate rocks unit flows from structural uplifts to structural and fluvial basins. This hydrostratigraphic unit supplies water to streams that drain the White River Plateau, hot springs at Glenwood Springs, and artesian wells in the Burns basin. (USGS)

  5. Transport properties of iodide in a sandy aquifer: Hydrogeological modelling and field tracer tests

    NASA Astrophysics Data System (ADS)

    Razafindratsima, Stephen; Péron, Olivier; Piscitelli, Anne; Gégout, Claire; Schneider, Vincent; Barbecot, Florent; Giffaut, Eric; Robinet, Jean-Charles; Le Cointe, Pierre; Montavon, Gilles

    2015-01-01

    The release of radioactive iodine into geological media from nuclear waste disposal is an issue that has to be considered since iodine is a biophilic element. 129I is, with 99Tc, one of the two long-lived radionuclides that have the highest mobility in radioactive waste disposal. Within this context, iodide retardation is still a matter of debate. A low value of the retardation factor is generally accepted in soils without organic matter, but the possibility for sorption cannot be completely ruled out. Since isotopic exchange with naturally occurring iodine is one of the main potential sorption mechanisms, site-specific retention parameters are needed. In the present paper, we study iodide transport in a sandy aquifer. A hydrogeological model was built to fit deuterium, bromide and iodide breakthrough data from in situ tracer test experiments. Within the precision range of the fitting, iodide is excluded from 2.5% of the effective porosity by anionic exclusion and presents a field retention factor (Kd) lower than 0.025 L/kg.

  6. Predevelopment Water-Level Contours for Aquifers in the Rainier Mesa and Shoshone Mountain area of the Nevada Test Site, Nye County, Nevada

    USGS Publications Warehouse

    Fenelon, Joseph M.; Laczniak, Randell J.; Halford, Keith J.

    2008-01-01

    Contaminants introduced into the subsurface of the Nevada Test Site at Rainier Mesa and Shoshone Mountain by underground nuclear testing are of concern to the U.S. Department of Energy and regulators responsible for protecting human health and safety. Although contaminants were introduced into low-permeability rocks above the regional flow system, the potential for contaminant movement away from the underground test areas and into the accessible environment is greatest by ground-water transport. The primary hydrologic control on this transport is evaluated and examined through a series of contour maps developed to represent the water-level 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. The contoured water-level 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, presented, and discussed in general terms as being one of three aquifer types?volcanic aquifer, upper carbonate aquifer, or lower carbonate aquifer. Each of these aquifer types was subdivided and mapped as independent continuous and isolated aquifers, based on the continuity of its component rock. Ground-water flow directions, as related to the transport of test-generated contaminants, were developed from water-level contours and are presented and discussed for each of the continuous aquifers. Contoured water-level altitudes vary across the study area and range from more than 5,000 feet in the volcanic aquifer beneath a recharge area in the northern part of the study area to less than 2,450 feet in the lower carbonate aquifer in the southern part of the study area. Variations in

  7. Predevelopment Water-Level Contours for Aquifers in the Rainier Mesa and Shoshone Mountain area of the Nevada Test Site, Nye County, Nevada

    SciTech Connect

    Joseph M. Fenelon; Randell J. Laczniak; and Keith J. Halford

    2008-06-24

    Contaminants introduced into the subsurface of the Nevada Test Site at Rainier Mesa and Shoshone Mountain by underground nuclear testing are of concern to the U.S. Department of Energy and regulators responsible for protecting human health and safety. Although contaminants were introduced into low-permeability rocks above the regional flow system, the potential for contaminant movement away from the underground test areas and into the accessible environment is greatest by ground-water transport. The primary hydrologic control on this transport is evaluated and examined through a series of contour maps developed to represent the water-level 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. The contoured water-level 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, presented, and discussed in general terms as being one of three aquifer types—volcanic aquifer, upper carbonate aquifer, or lower carbonate aquifer. Each of these aquifer types was subdivided and mapped as independent continuous and isolated aquifers, based on the continuity of its component rock. Ground-water flow directions, as related to the transport of test-generated contaminants, were developed from water-level contours and are presented and discussed for each of the continuous aquifers. Contoured water-level altitudes vary across the study area and range from more than 5,000 feet in the volcanic aquifer beneath a recharge area in the northern part of the study area to less than 2,450 feet in the lower carbonate aquifer in the southern part of the study area. Variations in

  8. Hydrogeochemical alteration of groundwater due to a CO2 injection test into a shallow aquifer in Northeast Germany

    NASA Astrophysics Data System (ADS)

    Dethlefsen, Frank; Peter, Anita; Hornbruch, Götz; Lamert, Hendrik; Garbe-Schönberg, Dieter; Beyer, Matthias; Dietrich, Peter; Dahmke, Andreas

    2014-05-01

    The accidental release of CO2 into potable aquifers, for instance as a consequence of a leakage out of a CO2 store site, can endanger drinking water resources due to the induced geochemical processes. A 10-day CO2 injection experiment into a shallow aquifer was carried out in Wittstock (Northeast Germany) in order to investigate the geochemical impact of a CO2 influx into such an aquifer and to test different monitoring methods. Information regarding the site investigation, the injection procedure monitoring setup, and first geochemical monitoring results are described in [1]. Apart from the utilization of the test results to evaluate monitoring approaches [2], further findings are presented on the evaluation of the geophysical monitoring [3], and the monitoring of stable carbon isotopes [4]. This part of the study focuses of the hydrogeochemical alteration of groundwater due to the CO2 injection test. As a consequence of the CO2 injection, major cations were released, i.e. concentrations increased, whereas major anion concentrations - beside bicarbonate - decreased, probably due to increased anion sorption capacity at variably charged exchange sites of minerals. Trace element concentrations increased as well significantly, whereas the relative concentration increase was far larger than the relative concentration increase of major cations. Furthermore, geochemical reactions show significant spatial heterogeneity, i.e. some elements such as Cr, Cu, Pb either increased in concentration or remained at stable concentrations with increasing TIC at different wells. Statistical analyses of regression coefficients confirm the different spatial reaction patterns at different wells. Concentration time series at single wells give evidence, that the trace element release is pH dependent, i.e. trace elements such as Zn, Ni, Co are released at pH of around 6.2-6.6, whereas other trace elements like As, Cd, Cu are released at pH of 5.6-6.4. [1] Peter, A., et al., Investigation of

  9. Application of the re-circulating tracer well test method to determine nitrate reaction rates in shallow unconfined aquifers.

    PubMed

    Burbery, Lee F; Flintoft, Mark J; Close, Murray E

    2013-02-01

    Five re-circulating tracer well tests (RCTWTs) have been conducted in a variety of aquifer settings, at four sites across New Zealand. The tests constitute the first practical assessment of the two-well RCTWT methodology described by Burbery and Wang (Journal of Hydrology, 2010; 382:163-173) and were aimed at evaluating nitrate reaction rates in situ. The performance of the RCTWTs differed significantly at the different sites. The RCTWT method performed well when it was applied to determine potential nitrate reaction rates in anoxic, electro-chemically reductive, nitrate-free aquifers of volcanic lithology, on the North Island, New Zealand. Regional groundwater flow was not fast-flowing in this setting. An effective first-order nitrate reaction rate in the region of 0.09 d(-1) to 0.26 d(-1) was determined from two RCTWTs applied at one site where a reaction rate of 0.37 d(-1) had previously been estimated from a push-pull test. The RCTWT method performed poorly, however, in a fast-flowing, nitrate-impacted fluvio-glacial gravel aquifer that was examined on the South Island, New Zealand. This setting was more akin to the hypothetical physiochemical problem described by Burbery and Wang (2010). Although aerobic conditions were identified as the primary reason for failure to measure any nitrate reaction in the gravel aquifer, failure to establish significant interflow in the re-circulation cell due to the heterogeneous nature of the aquifer structure, and natural variability exhibited in nitrate contaminant levels of the ambient groundwater further contributed to the poor performance of the test. Our findings suggest that in practice, environmental conditions are more complex than assumed by the RCTWT methodology, which compromises the practicability of the method as one for determining attenuation rates in groundwater based on tracing ambient contaminant levels. Although limited, there appears to be a scope for RCTWTs to provide useful information on potential

  10. Use of double-mass curves to determine drawdown in a long-term aquifer test in north-central Volusia County, Florida

    USGS Publications Warehouse

    Rutledge, A.T.

    1985-01-01

    A test well withdrew water from the upper Floridan aquifer system at an average of 530 gallons per minute from June 1978 to July 1979. Ground-water levels were monitored in wells open to the upper Floridan (artesian) aquifer system and in wells open to the surficial (water-table) aquifer. Double-mass curves were used to separate drawdown from natural water-level fluctuations. Drawdowns in the Floridan were 4.3 feet at a site 350 feet away from the pumped well, 4.1 feet at a site 1,000 feet away, 1.0 foot at a site 1.0 mile away, and 0.4 foot at a site 5.8 miles away. After an initial drawdown of 0.2 foot at a surficial aquifer well 1,000 feet from the pumped well, there was some recovery, and long-term drawdown averaged less than 0.2 foot. In a five-day aquifer test during a period of no rainfall in 1976, the ratio of surficial aquifer drawdown to Floridan aquifer system drawdown reached equilibrum at 0.05. The results of the long-term test indicate that this ratio is the upper limit of long-term drawdown because of capture of evapotranspiration and runoff during the long-term test. (USGS)

  11. Technical note: Analytical drawdown solution for steady-state pumping tests in two-dimensional isotropic heterogeneous aquifers

    NASA Astrophysics Data System (ADS)

    Zech, Alraune; Attinger, Sabine

    2016-05-01

    A new method is presented which allows interpreting steady-state pumping tests in heterogeneous isotropic transmissivity fields. In contrast to mean uniform flow, pumping test drawdowns in heterogeneous media cannot be described by a single effective or equivalent value of hydraulic transmissivity. An effective description of transmissivity is required, being a function of the radial distance to the well and including the parameters of log-transmissivity: mean, variance, and correlation length. Such a model is provided by the upscaling procedure radial coarse graining, which describes the transition of near-well to far-field transmissivity effectively. Based on this approach, an analytical solution for a steady-state pumping test drawdown is deduced. The so-called effective well flow solution is derived for two cases: the ensemble mean of pumping tests and the drawdown within an individual heterogeneous transmissivity field. The analytical form of the solution allows inversely estimating the parameters of aquifer heterogeneity. For comparison with the effective well flow solution, virtual pumping tests are performed and analysed for both cases, the ensemble mean drawdown and pumping tests at individual transmissivity fields. Interpretation of ensemble mean drawdowns showed proof of the upscaling method. The effective well flow solution reproduces the drawdown for two-dimensional pumping tests in heterogeneous media in contrast to Thiem's solution for homogeneous media. Multiple pumping tests conducted at different locations within an individual transmissivity field are analysed, making use of the effective well flow solution to show that all statistical parameters of aquifer heterogeneity can be inferred under field conditions. Thus, the presented method is a promising tool with which to estimate parameters of aquifer heterogeneity, in particular variance and horizontal correlation length of log-transmissivity fields from steady-state pumping test measurements.

  12. Modeling slug tests in unconfined aquifers taking into account water table kinematics, wellbore skin and inertial effects

    NASA Astrophysics Data System (ADS)

    Malama, Bwalya; Kuhlman, Kristopher L.; Barrash, Warren; Cardiff, Michael; Thoma, Michael

    2011-09-01

    Two models for slug tests conducted in unconfined aquifers are developed by (a) extending the unconfined KGS solution to oscillatory responses, yielding a model referred to herein as the unified model, and (b) replacing the constant head condition with the linearized kinematic condition at the water table. The models can be used to analyze the full range of responses from highly oscillatory to overdamped. The second model, refered to as the moving water table (MWT) model, is only applicable when effects of well bore skin are negligible. The models are validated by comparison with published solutions, and by application to a published case study of field tests conducted in wells without skin in an unconfined aquifer at the MSEA site in Nebraska. In this regard (a) the MWT model essentially yields the same results as the confined KGS model, except very close to the water table, and (b) the unified model yields slightly smaller aquifer K-values relative to the MWT model at all positions in the well. All model solutions yield comparable results when fitted to published field data obtained in an unconfined fluvial aquifer at the MSEA site in Nebraska. The unified model is fitted to field data collected in wells known to exhibit positive skin effects at the Boise Hydrogeophysical Research Site (BHRS) in Boise, Idaho. It is shown to yield hydraulic conductivity estimates of comparable magnitude to those obtained with the KGS model for overdamped responses, and the Springer-Gelhar model for oscillatory responses. Sensitivity of the MWT model to specific yield, Sy, and hydraulic anisotropy, κ is evaluated and the results, when plotted in log-log space and with consideration of log-scale time derivatives of the response, indicate that these two parameters should be estimable from slug test data, though challenges still remain.

  13. Permeability, geochemical, and water quality tests in support of an aquifer thermal energy storage site in Minnesota

    SciTech Connect

    Blair, S.C.; Deutsch, W.J.; Mitchell, P.J.

    1985-04-01

    This report describes the Underground Energy Storage Program's efforts to characterize physicochemical processes at DOE's ATES Field Test Facility (FTF) located on the University of Minnesota campus at St. Paul, Minnesota. Experimental efforts include: field tests at the St. Paul FTF to characterize fluid injectability and to evaluate the effectiveness of fluid-conditioning equipment, geochemical studies to investigate chemical reactions resulting from alterations to the aquifer's thermal regime, and laboratory tests on sandstone core from the site. Each experimental area is discussed and results obtained thus far are reported. 23 refs., 39 figs., 12 tabs.

  14. Geophysical Log Analysis of Selected Test Holes and Wells in the High Plains Aquifer, Central Platte River Basin, Nebraska

    USGS Publications Warehouse

    Anderson, J. Alton; Morin, Roger H.; Cannia, James C.; Williams, John H.

    2009-01-01

    The U.S. Geological Survey in cooperation with the Central Platte Natural Resources District is investigating the hydrostratigraphic framework of the High Plains aquifer in the Central Platte River basin. As part of this investigation, a comprehensive set of geophysical logs was collected from six test holes at three sites and analyzed to delineate the penetrated stratigraphic units and characterize their lithology and physical properties. Flow and fluid-property logs were collected from two wells at one of the sites and analyzed along with the other geophysical logs to determine the relative transmissivity of the High Plains aquifer units. The integrated log analysis indicated that the coarse-grained deposits of the alluvium and the upper part of the Ogallala Formation contributed more than 70 percent of the total transmissivity at this site. The lower part of the Ogallala with its moderately permeable sands and silts contributed some measureable transmissivity, as did the fine-grained sandstone of the underlying Arikaree Group, likely as a result of fractures and bedding-plane partings. Neither the lower nor the upper part of the siltstone- and claystone-dominated White River Group exhibited measurable transmissivity. The integrated analysis of the geophysical logs illustrated the utility of these methods in the detailed characterization of the hydrostratigraphy of the High Plains aquifer.

  15. Fate and transport of linear alkylbenzenesulfonate in a sewage- contaminated aquifer: A comparison of natural-gradient pulsed tracer tests

    USGS Publications Warehouse

    Krueger, C.J.; Barber, L.B.; Metge, D.W.; Field, J.A.

    1998-01-01

    Two natural-gradient tracer tests were conducted to determine the transport and biodegradation behavior of linear alkylbenzenesulfonate (LAS) surfactant under in situ conditions in a sewage-contaminated aquifer. The tests were conducted in two biogeochemically distinct zones of the aquifer: (1) an aerobic uncontaminated zone (oxic zone) and (2) a moderately aerobic, sewage-contaminated zone (transition zone). Chromatographic separation of the surfactant mixture was observed in both zones and attributed to the retardation of the longer alkyl chain homologues during transport. No significant loss of IAS mass was observed for the oxic zone while 20% of the LAS mass injected into the transition zone was removed due to biodegradation. Biodegradation preferentially removed the longer alkyl chain homologues and the external isomers (i.e., 2- and 3-phenyl). The removal of LAS mass coincided with a decrease in dissolved oxygen concentrations, the appearance of LAS metabolites, and an increase in the number of free-living bacteria with a concomitant change in bacteria morphology. The formation of LAS metabolites accounted for 86% of the LAS mass removed in the transition zone. Over the duration of the test, sorption and biodegradation enriched the LAS mixture in the more water-soluble and biologically resistant components.Two natural-gradient tracer tests were conducted to determine the transport and biodegradation behavior of linear alkylbenzenesulfonate (LAS) surfactant under in situ conditions in a sewage-contaminated aquifer. The tests were conducted in two biogeochemically distinct zones of the aquifer: (1) an aerobic uncontaminated zone (oxic zone) and (2) a moderately aerobic, sewage-contaminated zone (transition zone). Chromatographic separation of the surfactant mixture was observed in both zones and attributed to the retardation of the longer alkyl chain homologues during transport. No significant loss of LAS mass was observed for the oxic zone while 20% of the LAS

  16. Use of air-pressurized slug tests to estimate hydraulic conductivity at selected piezometers completed in the Santa Fe Group aquifer system, Albuquerque area, New Mexico

    USGS Publications Warehouse

    Thomas, Carole L.; Thorn, Conde R.

    2000-01-01

    The City of Albuquerque Public Works Department, Water Resources Management (City), is interested in quantifying aquifer hydraulic properties in the Albuquerque, New Mexico, area to better understand and manage water resources in the Middle Rio Grande Basin. In 1998, the City and the U.S. Geological Survey entered into a cooperative program to determine hydraulic properties of aquifer material adjacent to screened intervals of piezometers in the Albuquerque area. Investigators conducted slug tests from March 8 through April 8, 1999, to estimate hydraulic conductivity of aquifer material adjacent to the screened intervals of 25 piezometers from 11 nested- piezometer sites in the Albuquerque area. At 20 of the piezometers, slug-test responses were typical; at 2 piezometers, tests were prematurely terminated because the tests were taking too long to complete; and at 3 piezometers, test responses were oscillatory. Methods used to estimate hydraulic conductivity were the Bouwer and Rice method or the Cooper, Bredehoeft, and Papadopulos method for most tests; the Shapiro and Greene method for prematurely terminated tests; and the van der Kamp method for oscillatory tests. Hydraulic-conductivity estimates ranged from about 0.15 to 92 feet per day. In general, the smaller estimated values are associated with fine-grained aquifer materials and the larger estimated hydraulic-conductivity values are associated with coarse- grained aquifer materials adjacent to the screened intervals of the piezometers. Hydraulic-conductivity estimates ranged from 0.15 to 8.2 feet per day for aquifer materials adjacent to the screened intervals at 12 piezometers and from 12 to 41 feet per day for aquifer materials adjacent to the screened intervals at 10 piezometers. Hydraulic-conductivity estimates at four piezometers were greater than 41 feet per day.

  17. Analysis of complex pumping interactions during an aquifer test conducted at a well field in the coastal plain near Augusta, Georgia, October 2009

    USGS Publications Warehouse

    Gonthier, Gerald J.

    2009-01-01

    A 24-hour aquifer test was conducted in Well Field 2 near Augusta, Georgia, October 21–22, 2009, to characterize the hydraulic properties of the Midville aquifer system. The selected well was pumped at a rate of 684 gallons per minute. At the initiation of aquifer-test pumping, water levels in each of eight wells monitored for the test were still recovering from the well-field production. Because water levels had not stabilized, data analyses were needed to account for the ongoing recovery. Hydraulic properties of the Midville aquifer system were estimated by an approach based on the Theis model and superposition. The Midville aquifer system was modeled as a Theis aquifer. The principle of superposition was used to sum the effects of multiple pumping and recovery events from a single pumped well and to sum the effects of all pumped wells as the estimated total drawdown at a monitored well. Simulated drawdown at each monitored well was determined by using a spreadsheet (SUMTheis) function of aquifer transmissivity and storativity. Simulated drawdown values were transformed into simulated water levels, accounting for longterm water-level trends. The transmissivity and storativity values that were used to calibrate the simulated water levels to measured water levels (roughly 4,000 square feet per day and 2E-04, respectively) provide estimates of the transmissivity and storativity of the Midville aquifer system in the vicinity of Well Field 2. The approach used in this study can be applied to similar well-field tests in which incomplete drawdown recovery or other known pumping is evident.

  18. Convergent radial dispersion: a Laplace transform solution for aquifer tracer testing

    USGS Publications Warehouse

    Moench, A.F.

    1989-01-01

    A Laplace transform solution was obtained for the injection of a tracer in a well situated in a homogeneous aquifer where steady, horizontal, radially convergent flow has been established due to pumping at a second well. The standard advection-dispersion equation for mass transfer was used as the controlling equation. For boundary conditions, mass balances that account for mixing of the tracer with the fluid residing in the injection and pumping wells were used. The derived solution, which can be adapted for either resident or flux-averaged concentration, is of practical use only for the pumped well. This problem is of interest because it is easily applied to field determination of aquifer dispersivity and effective porosity. Breakthrough curves were obtained by numerical inversion of the Laplace transform solution. -from Author

  19. Groundwater modeling to evaluate interaquifer leakage in the Floridan aquifer system near Hunter Army Airfield and Fort Stewart

    USGS Publications Warehouse

    Cherry, Gregory S.

    2011-01-01

    Simulations using a modified regional groundwater- flow model were used to determine the amount of leakage from the Upper Floridan aquifer (UFA) through the Lower Floridan confining unit (LFC) into the Lower Floridan aquifer (LFA) resulting from pumping about 1 million gallons per day at newly constructed LFA production wells at Hunter Army Airfield and Fort Stewart in coastal Georgia. Simulated steadystate drawdown at each of the LFA production wells closely matched observed drawdown during a 72-hour aquifer test with the observed water levels reaching steady-state by the end of the test period. However, simulated drawdown was greater than observed drawdown in the UFA because of the short duration of the aquifer test and the time required for groundwater movement through the LFC into the LFA. Steadystate simulations provide an estimate of leakage based on the long-term continuous operation of each production well. Results of model simulations indicate that interaquifer leakage accounts for 48 percent of the flow to the well at Hunter Army Airfield, and 98 percent of the flow to the well at Fort Stewart. Simulated results near the Hunter Army Airfield production well indicated that 65 percent of the leakage from the UFA to the LFA occurs within a 1-mile radius, whereas simulated results near the Fort Stewart production well indicated 80-percent leakage from the UFA to the LFA within the same radius. The greater amount of leakage to the production well near Fort Stewart can be attributed to the higher transmissivity of the UFA and higher vertical hydraulic conductivity in the LFC near the well.

  20. Evaluation of In-Situ Arsenic Mitigation with Fe(II) Using Push-Pull Tests in the Ogallala Aquifer

    NASA Astrophysics Data System (ADS)

    Sheffer, N. A.; Scanlon, B. R.; Reedy, R. C.; Nicot, J.; Yang, C.; Stollenwerk, K. G.

    2010-12-01

    Reduction of the US EPA maximum contaminant level (MCL) for arsenic from 50 to 10 ppb has resulted in widespread violations. Groundwater arsenic concentrations exceed the MCL in 220 public water supply (PWS) systems in Texas, and in ~50% of all wells in the Texas southern High Plains (Ogallala) aquifer. Conventional ex-situ treatment technologies are costly and produce waste streams that present potentially insurmountable economic burdens for small PWS systems. The objective of this study was to evaluate the feasibility of in-situ mitigation of arsenic by introducing Fe(II) into the aquifer around producing wells. Aquifer water in this region is predominantly oxidizing and near neutral pH (median 7.2) with arsenic adsorbed onto Fe oxy-hydroxides that coat sediments. Dissolved arsenic concentrations range from <0.3 to 164 ppb (median 9.4 ppb) and occurs predominantly as arsenate that has been desorbed from Fe oxy-hydroxides by the counter ion effect as regional water chemistry changes from calcium- to sodium-type water. Push-pull pumping tests have been completed on a single experimental well where a total of 96 g of Fe(II) was dissolved in acidified (pH=3.5) water and injected into the surrounding aquifer. Prior to Fe injection, arsenic concentration in the well was 43 ppb with a pH of 7.6. By the end of the test, arsenic concentration was 20 ppb in produced water, representing a 58% reduction and 97% of the injected Fe was precipitated. The pH of the produced water remained at or above 7.0 throughout and returned to pre-test values by the end of the test. These initial results suggest that there is potential for mitigating produced groundwater arsenic using in-situ treatment in this region. Additional studies will evaluate operational issues relating to frequency and volume (mass) of injections required to reduce and maintain arsenic concentrations less than the MCL under full production demand requirements.

  1. Hydrogeology and water quality of the Floridan aquifer system and effects of Lower Floridan aquifer pumping on the Upper Floridan aquifer at Fort Stewart, Georgia

    USGS Publications Warehouse

    Clarke, John S.; Cherry, Gregory C.; Gonthier, Gerard J.

    2011-01-01

    constituent concentrations increased with depth, and water from all permeable zones contained sulfate at concentrations that exceeded the U.S. Environmental Protection Agency secondary maximum contaminant level of 250 milligrams per liter. A 72-hour aquifer test pumped LFA well 33P028 at 740 gallons per minute (gal/min), producing about 39 ft of drawdown in the pumped well and about 0.4 foot in nearby UFA well 33P029. Simulation using the U.S. Geological Survey finite-difference code MODFLOW was used to determine long-term, steady-state flow in the Floridan aquifer system, assuming the LFA well was pumped continuously at a rate of 740 gal/min. Simulated steady-state drawdown in the LFA was identical to that observed in pumped LFA well 33P028 at the end of the 72-hour test, with values larger than 1 ft extending 4.4 square miles symmetrically around the pumped well. Simulated steady-state drawdown in the UFA resulting from pumping in LFA well 33P028 exceeded 1 ft within a 1.4-square-mile circular area, and maximum drawdown in the UFA was 1.1 ft. Leakage from the UFA through the Lower Floridan confining unit contributed about 98 percent of the water to the well; lateral flow from specified-head model boundaries contributed about 2 percent. About 80 percent of the water supplied to LFA well 33P028 originated from within 1 mile of the well, and 49 percent was derived from within 0.5 mile of the well. Vertical hydraulic gradients and vertical leakage are progressively higher near the LFA pumped well which results in a correspondingly higher contribution of water from the UFA to the pumped well at distances closer to the pumped well. Simulated pumping-induced interaquifer leakage from the UFA to the LFA totaled 725 gal/min (1.04 million gallons per day), whereas simulated pumping at 205 gal/min (0.3 million gallons per day) from UFA well 33P029 produced the equivalent maximum drawdown as pumping LFA well 33P028 at 740 gal/min during the aquifer test. This equivalent pumpin

  2. Cross-well slug testing in unconfined aquifers: A case study from the Sleepers River Watershed, Vermont

    USGS Publications Warehouse

    Belitz, K.; Dripps, W.

    1999-01-01

    Normally, slug test measurements are limited to the well in which the water level is perturbed. Consequently, it is often difficult to obtain reliable estimates of hydraulic properties, particularly if the aquifer is anisotropic or if there is a wellbore skin. In this investigation, we use partially penetrating stress and observation wells to evaluate specific storage, radial hydraulic conductivity and anisotropy of the aquifer, and the hydraulic conductivity of the borehole skin. The study site is located in the W9 subbasin of the Sleepers River Research Watershed, Vermont. At the site, ~3 m of saturated till are partially penetrated by a stress well located in the center of the unconfined aquifer and six observation wells located above, below, and at the depth of the stress well at radial distances of 1.2 and 2.4 m. The observation wells were shut in with inflatable packers. The semianalytical solution of Butler (1995) was used to conduct a sensitivity analysis and to interpret slug test results. The sensitivity analysis indicates that the response of the stress well is primarily sensitive to radial hydraulic conductivity, less sensitive to anisotropy and the conductivity of the borehole skin, and nearly insensitive to specific storage. In contrast, the responses of the observation wells are sensitive to all four parameters. Interpretation of the field data was facilitated by generating type curves in a manner analogous to the method of Cooper et al. (1967). Because the value of radial hydraulic conductivity is obtained from a match point, the number of unknowns is reduced to three. The estimated values of radial hydraulic conductivity and specific storage are comparable to those derived from the methods of Bouwer and Rice (1976) and Cooper et al. (1967). The values and skin conductivity, however, could not have been obtained without the use of observation wells.Normally, slug test measurements are limited to the well in which the water level is perturbed

  3. Characterizing Hydraulic Properties and Ground-Water Chemistry in Fractured-Rock Aquifers: A User's Manual for the Multifunction Bedrock-Aquifer Transportable Testing Tool (BAT3)

    USGS Publications Warehouse

    Shapiro, Allen M.

    2007-01-01

    A borehole testing apparatus has been designed to isolate discrete intervals of a bedrock borehole and conduct hydraulic tests or collect water samples for geochemical analyses. This borehole testing apparatus, referred to as the Multifunction Bedrock-Aquifer Transportable Testing Tool (BAT3), includes two borehole packers, which when inflated can form a pressure-tight seal against smooth borehole walls; a pump apparatus to withdraw water from between the two packers; a fluid-injection apparatus to inject water between the two packers; pressure transducers to monitor fluid pressure between the two packers, as well as above and below the packers; flowmeters to monitor rates of fluid withdrawal or fluid injection; and data-acquisition equipment to record and store digital records from the pressure transducers and flowmeters. The generic design of this apparatus was originally discussed in United States Patent Number 6,761,062 (Shapiro, 2004). The prototype of the apparatus discussed in this report is designed for boreholes that are approximately 6 inches in diameter and can be used to depths of approximately 300 feet below land surface. The apparatus is designed to fit in five hard plastic boxes that can be shipped by overnight freight car-riers. The equipment can be assembled rapidly once it is removed from the shipping boxes, and the length of the test interval (the distance between the two packers) can be adjusted to account for different borehole conditions without reconfiguring the downhole components. The downhole components of the Multifunction BAT3 can be lowered in a borehole using steel pipe or a cable; a truck mounted winch or a winch and tripod can be used for this purpose. The equipment used to raise and lower the downhole components of the Multifunction BAT3 must be supplied on site, along with electrical power, a compressor or cylinders of compressed gas to inflate the packers and operate downhole valves, and the proper length of tubing to connect the

  4. Geology, hydrology, and results of tracer testing in the Galena-Platteville aquifer at a waste-disposal site near Byron, Illinois

    USGS Publications Warehouse

    Kay, Robert T.; Yeskis, Douglas J.; Prinos, Scott T.; Morrow, William S.; Vendl, Mark

    1999-01-01

    A study was conducted by the U.S. Geological Survey and the U.S. Environmental Protection Agency of the geohydrology of the dolomite bedrock at a waste-disposal site near Byron, Illinois. The study was designed to identify and characterize the flow pathways through the bedrock aquifer beneath the site. The geologic units of concern at the site are the Glenwood Formation of the Ancell Group, and the Platteville and Galena Groups. These deposits compose the Galena-Platteville aquifer and the underlying Harmony Hill Shale semiconfining unit. The Galena-Platteville aquifer is an unconfined aquifer. Geophysical logging, water levels, and aquifer-test data indicate the presence of interconnected, hydraulically active fractures in the middle of the Galena-Platteville aquifer (the upper flow pathway), and a second set of hydraulically active fractures (the lower flow pathway). The lower flow pathway may be present through much of the site. Few hydraulically active fractures are present in the upper part of the aquifer near the center of the site, but appear to be more numerous in the upper part of the aquifer in the western and northeastern parts of the site. Water-level data obtained during the tracer test indicate that pumping effects were present near the pumped wells. Pumping effects may have been present at several wells located along directions of identified fracture orientation from the pumped well. The upper part of the aquifer did not appear to be hydraulically well connected to the flow pathways supplying water to the pumped well. Large background changes in water levels obscured the effects of pumping and prevented calculation of aquifer properties. The velocity of the bromide tracer through the lower flow pathway under the hydraulic gradient resulting from the pumping was about 152 feet per day. Solution of the Darcy velocity equation results in a calculated effective porosity for this interval of 3.5 percent, indicating hydraulic interconnection between the

  5. Solutions of test problems for disposal of CO2 in saline aquifers

    SciTech Connect

    Pruess, Karsten; Garcia, Julio

    2003-03-05

    This report presents detailed results for three flow problems involving CO2 migration in saline aquifers, that had been posed as part of an international code intercomparison study. Selected data for PVT properties of aqueous mixtures involving CO2 are given, and the dynamics of immiscible displacement of an aqueous phase by supercritical CO2 is discussed. Simulations were conducted with a version of the TOUGH2 general purpose reservoir simulator that includes a special property package for supercritical CO2. The results can serve as benchmarks for debugging numerical simulation models.

  6. Interpretation of Flow Logs from Nevada Test Site Boreholes to Estimate Hydraulic conductivity Using Numerical Simulations Constrained by Single-Well Aquifer Tests

    SciTech Connect

    Garcia, C. Amanda; Halford, Keith J.; Laczniak, Randell J.

    2010-02-12

    Hydraulic conductivities of volcanic and carbonate lithologic units at the Nevada Test Site were estimated from flow logs and aquifer-test data. Borehole flow and drawdown were integrated and interpreted using a radial, axisymmetric flow model, AnalyzeHOLE. This integrated approach is used because complex well completions and heterogeneous aquifers and confining units produce vertical flow in the annular space and aquifers adjacent to the wellbore. AnalyzeHOLE simulates vertical flow, in addition to horizontal flow, which accounts for converging flow toward screen ends and diverging flow toward transmissive intervals. Simulated aquifers and confining units uniformly are subdivided by depth into intervals in which the hydraulic conductivity is estimated with the Parameter ESTimation (PEST) software. Between 50 and 150 hydraulic-conductivity parameters were estimated by minimizing weighted differences between simulated and measured flow and drawdown. Transmissivity estimates from single-well or multiple-well aquifer tests were used to constrain estimates of hydraulic conductivity. The distribution of hydraulic conductivity within each lithology had a minimum variance because estimates were constrained with Tikhonov regularization. AnalyzeHOLE simulated hydraulic-conductivity estimates for lithologic units across screened and cased intervals are as much as 100 times less than those estimated using proportional flow-log analyses applied across screened intervals only. Smaller estimates of hydraulic conductivity for individual lithologic units are simulated because sections of the unit behind cased intervals of the wellbore are not assumed to be impermeable, and therefore, can contribute flow to the wellbore. Simulated hydraulic-conductivity estimates vary by more than three orders of magnitude across a lithologic unit, indicating a high degree of heterogeneity in volcanic and carbonate-rock units. The higher water transmitting potential of carbonate-rock units relative

  7. Interpretation of Flow Logs from Nevada Test Site Boreholes to Estimate Hydraulic Conductivity Using Numerical Simulations Constrained by Single-Well Aquifer Tests

    USGS Publications Warehouse

    Garcia, C. Amanda; Halford, Keith J.; Laczniak, Randell J.

    2010-01-01

    Hydraulic conductivities of volcanic and carbonate lithologic units at the Nevada Test Site were estimated from flow logs and aquifer-test data. Borehole flow and drawdown were integrated and interpreted using a radial, axisymmetric flow model, AnalyzeHOLE. This integrated approach is used because complex well completions and heterogeneous aquifers and confining units produce vertical flow in the annular space and aquifers adjacent to the wellbore. AnalyzeHOLE simulates vertical flow, in addition to horizontal flow, which accounts for converging flow toward screen ends and diverging flow toward transmissive intervals. Simulated aquifers and confining units uniformly are subdivided by depth into intervals in which the hydraulic conductivity is estimated with the Parameter ESTimation (PEST) software. Between 50 and 150 hydraulic-conductivity parameters were estimated by minimizing weighted differences between simulated and measured flow and drawdown. Transmissivity estimates from single-well or multiple-well aquifer tests were used to constrain estimates of hydraulic conductivity. The distribution of hydraulic conductivity within each lithology had a minimum variance because estimates were constrained with Tikhonov regularization. AnalyzeHOLE simulated hydraulic-conductivity estimates for lithologic units across screened and cased intervals are as much as 100 times less than those estimated using proportional flow-log analyses applied across screened intervals only. Smaller estimates of hydraulic conductivity for individual lithologic units are simulated because sections of the unit behind cased intervals of the wellbore are not assumed to be impermeable, and therefore, can contribute flow to the wellbore. Simulated hydraulic-conductivity estimates vary by more than three orders of magnitude across a lithologic unit, indicating a high degree of heterogeneity in volcanic and carbonate-rock units. The higher water transmitting potential of carbonate-rock units relative

  8. Data from pumping and injection tests and chemical sampling in the geothermal aquifer at Klamath Falls, Oregon

    USGS Publications Warehouse

    Benson, S.M.; Janik, C.J.; Long, D.C.; Solbau, R.D.; Lienau, P.J.

    1984-01-01

    A seven-week pumping and injection tests in the geothermal aquifer at Klamath Falls, Oregon, in 1983 provided new information on hydraulic properties of the aquifer. The Open-File Data Report on the tests includes graphs of water levels measured in 50 wells, temperature measurement in 17 wells , daily air-temperatures in relation to discharge of thermal water from more than 70 pumped and artesian wells, tables of monthly mean air temperatures and estimates of discharges of thermal water during a normal year, and tables of chemical and isotopic analyses on samples from 12 wells. The water-level measurements reflect the effects of pumping, injection, and recovery over about 1.7 square miles of the hot-well area of Klamath Falls. The pumped well, City Well No 1, and the injection well at the Klamath County Museum are components of a proposed District Heating Plan. The study was funded principally under contracts from the U.S. Department of Energy to the Lawrence Berkeley Laboratory, Stanford University, and the Oregon Institute of Technology, with coordination and chemical sampling provided under the Geothermal Research Program, U.S. Geological Survey. Support was received from the City of Klamath Falls, Klamath County Chamber of Commerce, Citizens for Responsible Geothermal Development, and many citizen volunteers. (USGS)

  9. A multitracer test proving the reliability of Rayleigh equation-based approach for assessing biodegradation in a BTEX contaminated aquifer.

    PubMed

    Fischer, Anko; Bauer, Jana; Meckenstock, Rainer U; Stichler, Willibald; Griebler, Christian; Maloszewski, Piotr; Kästner, Matthias; Richnow, Hans H

    2006-07-01

    Compound-specific stable isotope analysis (CSIA) is one of the most important methods for assessing biodegradation activities in contaminated aquifers. Although the concept is straightforward, the proof that the method cannot be only used for a qualitative analysis but also to quantify biodegradation in the subsurface was missing. We therefore performed a multitracer test in the field with ring-deuterated (d5) and completely (d8) deuterium-labeled toluene isotopologues (400 g) as reactive tracers as well as bromide as a conservative tracer. The compounds were injected into the anoxic zone of a BTEX plume located down-gradient of the contaminant source. Over a period of 4.5 months the tracer concentrations were analyzed at two control planes located 24 and 35 m downgradient of the injection well. Deuterium-labeled benzylsuccinate was found in the aquifer, indicating the anaerobic biodegradation of deuterated toluene via the benzylsuccinate synthase pathway. Three independent methods were applied to quantify biodegradation of deuterated toluene. First, fractionation of toluene-d8 and toluene-d5 using the Rayleigh equation and an appropriate laboratory-derived isotope fractionation factor was used for the calculation of the microbial decomposition of deuterated toluene isotopologues (CSIA-method). Second, the biodegradation was quantified by the changes of the concentrations of deuterated toluene relative to bromide. Both methods gave similar results, implying that the CSIA-method is a reliable tool to quantify biodegradation in contaminated aquifers. The results of both methods yielded a biodegradation of deuterated toluene isotopologues of approximately 23-29% for the first and 44-51% for the second control plane. Third, the mineralization of deuterated toluene isotopologues was verified by determination of the enrichment of deuterium in the groundwater. This method indicated that parts of deuterium were assimilated into the biomass of toluene degrading

  10. Plan for proposed aquifer hydraulic testing and groundwater sampling at Everest, Kansas, in January-February 2006.

    SciTech Connect

    LaFreniere, L. M.; Environmental Science Division

    2006-01-31

    On September 8-9, 2005, representatives of the Kansas Department of Health and Environment (KDHE), the Commodity Credit Corporation of the U.S. Department of Agriculture (CCC/USDA), and Argonne National Laboratory met at the KDHE's offices in Topeka to review the status of the CCC/USDA's environmental activities in Kansas. A key CCC/USDA goal for this meeting was to obtain KDHE input on the selection of possible remedial approaches to be examined as part of the Corrective Action Study (CAS) for this site. As a result of the September meeting, the KDHE recommended several additional activities for the Everest site, to further assist in selecting and evaluating remedial alternatives for the CAS. The requested actions included the following: (1) Construction of several additional interpretive cross sections to improve the depiction of the hydrogeologic characteristics affecting groundwater and contaminant movement along the apparent main plume migration pathway to the north-northwest of the former CCC/USDA facility, and in the vicinity of the Nigh property. (2) Identification of potential locations for several additional monitoring wells, to better constrain the apparent western and northwestern margins of the existing groundwater plume. (3) Development of technical recommendations for a stepwise pumping study of the Everest aquifer unit in the area near and to the north of the Nigh property. On October 21, 2005, Argonne issued a brief Cross Section Analysis (Argonne 2006a) addressing these concerns, on behalf of the CCC/USDA. This report includes the following: (1) Preliminary recommendations for the siting of three new monitoring wells, at locations identified by the KDHE. Argonne also suggested, however, that the installation and sampling of these wells be deferred until after completion of the CAS evaluation. (2) A proposed strategy for testing of the Everest aquifer unit near the Nigh property, involving initial test pumping of the former Nigh domestic well and

  11. Testing of stack-unit/aquifer sensitivity analysis using contaminant plume distribution in the subsurface of Savannah River Site, South Carolina, USA

    USGS Publications Warehouse

    Rine, J.M.; Shafer, J.M.; Covington, E.; Berg, R.C.

    2006-01-01

    Published information on the correlation and field-testing of the technique of stack-unit/aquifer sensitivity mapping with documented subsurface contaminant plumes is rare. The inherent characteristic of stack-unit mapping, which makes it a superior technique to other analyses that amalgamate data, is the ability to deconstruct the sensitivity analysis on a unit-by-unit basis. An aquifer sensitivity map, delineating the relative sensitivity of the Crouch Branch aquifer of the Administrative/Manufacturing Area (A/M) at the Savannah River Site (SRS) in South Carolina, USA, incorporates six hydrostratigraphic units, surface soil units, and relevant hydrologic data. When this sensitivity map is compared with the distribution of the contaminant tetrachloroethylene (PCE), PCE is present within the Crouch Branch aquifer within an area classified as highly sensitive, even though the PCE was primarily released on the ground surface within areas classified with low aquifer sensitivity. This phenomenon is explained through analysis of the aquifer sensitivity map, the groundwater potentiometric surface maps, and the plume distributions within the area on a unit-by- unit basis. The results of this correlation show how the paths of the PCE plume are influenced by both the geology and the groundwater flow. ?? Springer-Verlag 2006.

  12. KGS-HighK: A Fortran 90 program for simulation of hydraulic tests in highly permeable aquifers

    USGS Publications Warehouse

    Zhan, X.; Butler, J.J.

    2006-01-01

    Slug and pumping tests (hydraulic tests) are frequently used by hydrogeologists to obtain in-situ estimates of the transmissive and storage properties of a formation (Streltsova, 1988; Kruseman and de Ridder, 1990; Butler, 1998). In aquifers of high hydraulic conductivity, hydraulic tests are affected by mechanisms that are not considered in the analysis of tests in less permeable media (Bredehoeft et al., 1966). Inertia-induced oscillations in hydraulic head are the most common manifestation of such mechanisms. Over the last three decades, a number of analytical solutions that incorporate these mechanisms have been developed for the analysis of hydraulic tests in highly permeable aquifers (see Butler and Zhan (2004) for a review of this previous work). These solutions, however, are restricted to a subset of the conditions commonly encountered in the field. Recently, a more general solution has been developed that builds on this previous work to remove many of the limitations imposed by these earlier approaches (Butler and Zhan, 2004). The purpose of this note is to present a Fortran 90 program, KGS-HighK, for the evaluation of this new solution. This note begins with a brief overview of the conceptual model that motivated the development of the solution of Butler and Zhan (2004) for pumping- and slug-induced flow to/from a central well. The major steps in the derivation of that solution are described, but no details are given. Instead, a Mathematica notebook is provided for those interested in the derivation details. The key algorithms used in KGS-HighK are then described and the program structure is briefly outlined. A field example is provided to demonstrate program performance. The note concludes with a short summary section. ?? 2005 Elsevier Ltd. All rights reserved.

  13. Analysis of tests of subsurface injection, storage, and recovery of freshwater in the lower Floridan aquifer, Okeechobee County, Florida

    USGS Publications Warehouse

    Quinones-Aponte, Vicente; Kotun, Kevin; Whitley, J.F.

    1996-01-01

    A series of freshwater subsurface injection, storage, and recovery tests were conducted at an injection-well site near Lake Okeechobee in Okeechobee County, Florida, to assess the recoverability of injected canal water from the Lower Floridan aquifer. At the study site, the Lower Floridan aquifer is characterized as having four local, relatively independent, high-permeability flow zones (389 to 398 meters, 419 to 424 meters, 456 to 462 meters, and 472 to 476 meters below sea level). Four subsurface injection, storage, and recovery cycles were performed at the Lake Okeechobee injection-well site in which volumes of water injected ranged from about 387,275 to 1,343,675 cubic meters for all the cycles, and volumes of water recovered ranged from about 106,200 to 484,400 cubic meters for cycles 1, 2, and 3. The recovery efficiency for successive cycles 2 and 3 increased from 22 to 36 percent and is expected to continue increasing with additional cycles. A comparison of chloride concentration breakthrough curves at the deep monitor well (located about 171 meters from the injection well) for cycles 1, 4, and test no. 4 (from a previous study) revealed unexpected finings. One significant result was that the concentration asymptote, expected to be reached at concentration levels equivalent or close to the injected water concentration, was instead reached at higher concentration levels. The injection to recovery rate ratio might affect the chloride concentration breakthrough curve at the deep monitor well, which could explain this unexpected behavior. Because there are four high-permeability zones, if the rate of injection is smaller than the rate of recovery (natural artesian flow), the head differential might not be transmitted through the entire open wellbore, and injected water would probably flow only through the upper high- permeability zones. Therefore, observed chloride concentration values at the deep monitor well would be higher than the concentration of the

  14. Interpretation of oscillatory water levels in observation wells during aquifer tests in fractured rock

    USGS Publications Warehouse

    Shapiro, A.M.

    1989-01-01

    Oscillatory water levels are predicted by the equations coupling the fluid movement in the observation well and the fluid movement in the surrounding formation. The equivalent-porous medium and dual-porosity models of fractured rock are two models considered in this analysis; however, other conceptual models of fractured media can also be coupled with the model presented here for fluid movement in the observation well. Type curves for the response of water levels in observation wells due to pumping in another well are generated by numerical inversion of the Laplace transform solution to the governing equations. Overdamped conditions, where inertial effects are insignificant, and underdamped conditions, where oscillations arise, are predicted by the solution to the governing equations. By matching water level measurements with the appropriate type curve, a conceptual model of the formation can be identified, and aquifer properties can be estimated. -from Author

  15. Aquifer tests in the flood-plain alluvium and Santa Fe group at the Rio Grande near Canutillo, El Paso County, Texas

    USGS Publications Warehouse

    Nickerson, Edward L.

    1989-01-01

    An aquifer system consisting of the Rio Grande flood-plain alluvium and Santa Fe Group underlying the southern Mesilla Valley in Dona Ana County, New Mexico and El Paso County, Texas has become an important source of water for both municipal and agricultural uses. Determination of aquifer properties is essential in order to evaluate groundwater potential for increasing water demand and potential streamflow depletion of the Rio Grande due to groundwater development. The aquifer system at the Canutillo well field hydrologic section was divided into a shallow, intermediate, and deep zone based on geohydrologic characteristics. Aquifer properties of specific zones at the test site were determined from a series of multiple-well aquifer tests conducted from December 3, 1985 through January 20, 1986. The Rio Grande is hydraulically connected to the shallow flood-plain alluvium. Water generally occurs within the shallow zone under unconfined conditions, within the intermediate zone under semiconfined conditions, and within the deep zone under confined conditions. (USGS)

  16. HYDROGEL TRACER BEADS: THE DEVELOPMENT, MODIFICATION, AND TESTING OF AN INNOVATIVE TRACER FOR BETTER UNDERSTANDING LNAPL TRANSPORT IN KARST AQUIFERS

    SciTech Connect

    Amanda Laskoskie, Harry M. Edenborn, and Dorothy J. Vesper

    2012-01-01

    The goal of this specific research task is to develop proxy tracers that mimic contaminant movement to better understand and predict contaminant fate and transport in karst aquifers. Hydrogel tracer beads are transported as a separate phase than water and can used as a proxy tracer to mimic the transport of non-aqueous phase liquids (NAPL). They can be constructed with different densities, sizes & chemical attributes. This poster describes the creation and optimization of the beads and the field testing of buoyant beads, including sampling, tracer analysis, and quantitative analysis. The buoyant beads are transported ahead of the dissolved solutes, suggesting that light NAPL (LNAPL) transport in karst may occur faster than predicted from traditional tracing techniques. The hydrogel beads were successful in illustrating this enhanced transport.

  17. Carbonate aquifers

    USGS Publications Warehouse

    Cunningham, Kevin J.; Sukop, Michael; Curran, H. Allen

    2012-01-01

    Only limited hydrogeological research has been conducted using ichnology in carbonate aquifer characterization. Regardless, important applications of ichnology to carbonate aquifer characterization include its use to distinguish and delineate depositional cycles, correlate mappable biogenically altered surfaces, identify zones of preferential groundwater flow and paleogroundwater flow, and better understand the origin of ichnofabric-related karst features. Three case studies, which include Pleistocene carbonate rocks of the Biscayne aquifer in southern Florida and Cretaceous carbonate strata of the Edwards–Trinity aquifer system in central Texas, demonstrate that (1) there can be a strong relation between ichnofabrics and groundwater flow in carbonate aquifers and (2) ichnology can offer a useful methodology for carbonate aquifer characterization. In these examples, zones of extremely permeable, ichnofabric-related macroporosity are mappable stratiform geobodies and as such can be represented in groundwater flow and transport simulations.

  18. MULTISPECIES REACTIVE TRACER TEST IN A SAND AND GRAVEL AQUIFER, CAPE COD, MASSACHUSETTS: PART 1: EXPERIMENTAL DESIGN AND TRANSPORT OF BROMIDE AND NICKEL-EDTA TRACERS

    EPA Science Inventory

    In this report, we summarize a portion of the results of a large-scale tracer test conducted at the U. S. Geological Survey research site on Cape Cod, Massachusetts. The site is located on a large sand and gravel glacial outwash plain in an unconfined aquifer. In April 1993, ab...

  19. Aquifer tests and simulation of ground-water flow in Triassic sedimentary rocks near Colmar, Bucks and Montgomery Counties, Pennsylvania

    USGS Publications Warehouse

    Risser, Dennis W.; Bird, Philip H.

    2003-01-01

    This report presents the results of a study by the U.S. Geological Survey in cooperation with the U.S. Environmental Protection Agency to evaluate ground-water flow in Triassic sedimentary rocks near Colmar, in Bucks and Montgomery Counties, Pa. The study was conducted to help the U.S. Environmental Protection Agency evaluate remediation alternatives at the North Penn Area 5 Superfund Site near Colmar, where ground water has been contaminated by volatile organic solvents (primarily trichloroethene). The investigation focused on determining the (1) drawdown caused by separately pumping North PennWater Authority wells NP?21 and NP?87, (2) probable paths of groundwater movement under present-day (2000) conditions (with NP?21 discontinued), and (3) areas contributing recharge to wells if pumping from wells NP-21 or NP?87 were restarted and new recovery wells were installed. Drawdown was calculated from water levels measured in observation wells during aquifer tests of NP?21 and NP?87. The direction of ground-water flow was estimated by use of a three-dimensional ground-water-flow model. Aquifer tests were conducted by pumping NP?21 for about 7 days at 257 gallons per minute in June 2000 and NP?87 for 3 days at 402 gallons per minute in May 2002. Drawdown was measured in 45 observation wells during the NP?21 test and 35 observation wells during the NP?87 test. Drawdown in observation wells ranged from 0 to 6.8 feet at the end of the NP?21 test and 0.5 to 12 feet at the end of the NP?87 test. The aquifer tests showed that ground-water levels declined mostly in observation wells that were completed in the geologic units penetrated by the pumped wells. Because the geologic units dip about 27 degrees to the northwest, shallow wells up dip to the southeast of the pumped well showed a good hydraulic connection to the geologic units stressed by pumping. Most observation wells down dip from the pumping well penetrated units higher in the stratigraphic section that were not well

  20. Analysis of Hydraulic Responses from the ER-6-1 Multiple-Well Aquifer Test, Yucca Flat FY 2004 Testing Program, Nevada Test Site, Nye County, Nevada, Rev. No.: 0

    SciTech Connect

    Greg Ruskauff

    2005-06-01

    This report documents the interpretation and analysis of the hydraulic data collected for the Fiscal Year (FY) 2004 Multiple-Well Aquifer Test-Tracer Test (MWAT-TT) conducted at the ER-6-1 Well Cluster in Yucca Flat Corrective Action Unit (CAU) 97, on the Nevada Test Site (NTS). The MWAT-TT was performed to investigate CAU-scale groundwater flow and transport processes related to the transport of radionuclides from sources on the NTS through the Lower Carbonate Aquifer (LCA) Hydrostratigraphic Unit (HSU). The ER-6-1 MWAT-TT was planned and executed by contractor participants for the Underground Test Area (UGTA) Project of the Environmental Restoration (ER) program of the U.S. Department of Energy (DOE), National Nuclear Security Administration Nevada Site Office (NNSA/NSO). Participants included Stoller-Navarro Joint Venture (SNJV), the Environmental Engineering Services Contractor; Bechtel Nevada (BN); the Desert Research Institute (DRI); Los Alamos National Laboratory; and the University of Nevada, Las Vegas-Harry Reid Center. The SNJV team consists of the S.M. Stoller Corporation, Navarro Research and Engineering, Battelle Memorial Institute, INTERA Inc., and Weston Solutions, Inc. The MWAT-TT was implemented according to the ''Underground Test Area Project, ER-6-1 Multi-Well Aquifer Test - Tracer Test Plan'' (SNJV, 2004a) issued in April 2004. The objective of the aquifer test was to determine flow processes and local hydraulic properties for the LCA through long-term constant-rate pumping at the well cluster. This objective was to be achieved in conjunction with detailed sampling of the composite tracer breakthrough at the pumping well, as well as with depth-specific sampling and logging at multiple wells, to provide information for the depth-discrete analysis of formation hydraulic properties, particularly with regard to fracture properties.

  1. Spatial analysis of aquifer response times for radial flow processes: Nondimensional analysis and laboratory-scale tests

    NASA Astrophysics Data System (ADS)

    Jazaei, Farhad; Simpson, Matthew J.; Clement, T. Prabhakar

    2016-01-01

    A fundamental concept in groundwater hydrology is the notion of steady state, or equilibrium conditions. When a system at some initial steady state condition is perturbed by pumping, a transient cone of depression will develop and the system will approach a new steady state condition. Understanding the time scale required for the transient process to occur is of practical interest since it would help practitioners decide whether to use a steady state model or a more complicated transient model. Standard approaches to estimate the response time use simple scaling relationships which neglect spatial variations. Alternatively, others define the response time to be the amount of time taken for the difference between the transient and steady state solutions to fall below some arbitrary tolerance level. Here, we present a novel approach and use the concept of mean action time to predict aquifer response time scales in a two-dimensional radial geometry for pumping, injection and recovery processes. Our approach leads to relatively simple closed form expressions that explicitly show how the time scale depends on the hydraulic parameters and position. Furthermore, our dimensionless framework allows us to predict the response time scales for a range of applications including small scale laboratory problems and large scale field problems. Our analysis shows that the response time scales vary spatially, but are equivalent for pumping, injection and associated recovery processes. Furthermore, the time scale is independent of the pumping or injection flow rate. We test these predictions in a laboratory scale aquifer and find that our physical measurements corroborate the theoretical predictions.

  2. Development and testing of a compartmentalized reaction network model for redox zones in contaminated aquifers

    USGS Publications Warehouse

    Abrams, R.H.; Loague, K.; Kent, D.B.

    1998-01-01

    The work reported here is the first part of a larger effort focused on efficient numerical simulation of redox zone development in contaminated aquifers. The sequential use of various electron acceptors, which is governed by the energy yield of each reaction, gives rise to redox zones. The large difference in energy yields between the various redox reactions leads to systems of equations that are extremely ill-conditioned. These equations are very difficult to solve, especially in the context of coupled fluid flow, solute transport, and geochemical simulations. We have developed a general, rational method to solve such systems where we focus on the dominant reactions, compartmentalizing them in a manner that is analogous to the redox zones that are often observed in the field. The compartmentalized approach allows us to easily solve a complex geochemical system as a function of time and energy yield, laying the foundation for our ongoing work in which we couple the reaction network, for the development of redox zones, to a model of subsurface fluid flow and solute transport. Our method (1) solves the numerical system without evoking a redox parameter, (2) improves the numerical stability of redox systems by choosing which compartment and thus which reaction network to use based upon the concentration ratios of key constituents, (3) simulates the development of redox zones as a function of time without the use of inhibition factors or switching functions, and (4) can reduce the number of transport equations that need to be solved in space and time. We show through the use of various model performance evaluation statistics that the appropriate compartment choice under different geochemical conditions leads to numerical solutions without significant error. The compartmentalized approach described here facilitates the next phase of this effort where we couple the redox zone reaction network to models of fluid flow and solute transport.

  3. Development, calibration, and testing of ground-water flow models for the Mississippi River Valley alluvial aquifer in eastern Arkansas using one-square-mile cells

    USGS Publications Warehouse

    Mahon, G.L.; Poynter, D.T.

    1993-01-01

    Significant water-level declines in the Mississippi River Valley alluvial aquifer prompted the need to better understand the flow system in the aquifer which, in turn, led to the development of digital groundwater flow models of the alluvial aquifer. Two models were developed in the eastern Arkansas study area with the Arkansas River dividing the study area and functioning as a hydrologic boundary to the models. Both models simulate groundwater flow in one layer with recharge entering the aquifer from head-dependent surface infiltration through the overlying confining unit and from seepage through river beds. Digital models were used to simulate flow in the aquifer during seven stress periods between 1918 and 1987. Pumpage used in the simulations ranged from 83,400,000 to 412,000,000 cu ft/d in the north model and from 12,800,000 to 58,500,000 cu ft/d in the south model. Three different spatial and temporal pumpage scenarios were tested to simulate pumpage stress in the models. The pumpage distribution used in the calibrated model was based on a combination of all three scenarios. Several criteria were used during model development to determine how well the model simulated conditions in the aquifer. Potentiometric maps of model-computed water levels were compared to measured data to check the computed water levels and direction of flow. Hydrographs of observation wells were compared to computed water levels at corresponding model cells to assess the temporal distribution of pumpage. A root-mean-square error analysis was performed during calibration by comparing observation-well and model-computed water levels for 1972. Sensitivity analyses were performed to determine the effects of changes in input parameters on computed heads (water levels). Both models were sensitive to changes in recharge and pumpage but the south model generally was less sensitive than the north model.

  4. Influence of Eco-hydrological Changes on Flow Velocities in a Shallow Alluvial Aquifer - Findings From Tracer Tests at the Merdingen Test Site, Germany.

    NASA Astrophysics Data System (ADS)

    Goeppert, N.; Kaess, W.; Hoetzl, H.; Goldscheider, N.

    2008-12-01

    Since 1979, the Merdingen test site, located in the alluvial deposits of the Upper Rhine Graben, has been used for tracer tests using fluorescent dyes, heavy metals, microorganisms, microspheres and other tracers. In 1999, the storm Lothar badly affected the test site and significantly changed the vegetation cover. The previously forested area is now predominantly covered by bushes and a few remaining trees. 13 wells can be used for tracer experiments over a distance of up to 200 meters. Before the storm (1988), uranine gave a maximum flow velocity (vmax) of 1.08 m/h and a peak flow velocity (vpeak) of 0.07 m/h over a distance of 25 meters. Vmax was not influenced by rainfall, whereas the peak might have been accelerated by rainfall events. In 2005, uranine gave a vmax of 2.55 m/h and a vpeak of 0.07 m/h, during a period of falling water table and no rainfalls. This means that vmax increased by a factor of 2.3, whereas vpeak remained stable. The vmax for 1 μm microspheres increased by a factor of 4.6 between 1988 and 2005, the vmax for the Serratia marcescens bacterium increased by the same factor, while vpeak remained stable. This behavior can, at least partly, be explained by the change in vegetation caused by the storm, particularly by the impact of uprooted trees and intensively rooting bushes on the shallow aquifer, which obviously created additional preferential flowpaths that allow for higher maximum velocities. The even higher observed increase of the maximum velocities for bacteria and microspheres can be explained by the fact that particle transport is known to be even more influenced by preferential flowpaths than solute transport (pore exclusion). Our findings suggest that vegetation changes, particularly trees being overthrown and uprooted, can actually influence groundwater flow velocities in shallow alluvial aquifers, which can result in higher maximum transport velocities of microorganisms along preferential flowpaths.

  5. Use of a 2-inch, dual screen well to conduct aquifer tests in the upper and lower Lost lake aquifer zones: Western sector, A/M area, SRS

    SciTech Connect

    Hiergesell, R.A.; Novick, J.S.

    1996-09-01

    The Western Sector, A/M Area is located just west of the M-Area Settling Basin on an upland area. The area is adjacent to the gently inclined area where the upland drops off to the Savannah River floodplain. Water in the parts of the uppermost aquifers contains dissolved contaminants which originated at the land surface and have leached downward into the groundwater. Subsurface contamination originated in the locality of the M-Area Settling Basin and Lost Lake, which is a Carolina Bay. These locations functioned as disposal sites for industrial solvents during the early years of operation of the Savannah River Site. The primary groundwater contaminants are trichloroethylene (TCE) and tetrachloroethylene (PCE), and groundwater concentrations of TCE are significantly greater than the PCE.

  6. A general analytical model for pumping tests in radial finite two-zone confined aquifers with Robin-type outer boundary

    NASA Astrophysics Data System (ADS)

    Lin, Ye-Chen; Yang, Shaw-Yang; Fen, Chiu-Shia; Yeh, Hund-Der

    2016-09-01

    This study develops a general analytical model for describing transient drawdown distribution induced by pumping at a finite-radius well in a radial two-zone confined aquifer of finite areal extent with Robin-type condition at both inner and outer boundaries. This model is also applicable to heat conduction problems for a composite hollow cylinder on the basis of the analogy between heat flow and groundwater flow. The time-domain solution of the model is derived by the methods of Laplace transform, Bromwich integral, and residue theorem. This new solution can reduce to the solution for constant-head test (CHT) or constant-rate test (CRT) problem by specifying appropriate coefficients at the Robin inner boundary condition. The solution describing the flow rate across the wellbore due to CHT is further developed by applying Darcy's law to the new solution. In addition, steady-state solutions for both CHT and CRT are also developed based on the approximation for Bessel functions with very small argument values. Many existing solutions for transient flow in homogeneous or two-zone finite aquifers with Dirichlet or no-flow condition at the outer boundary are shown to be special cases of the present solution. Furthermore, the sensitivity analysis is also performed to investigate the behaviors of the wellbore flow due to CHT and the aquifer drawdown induced by CRT in response to the change in each of aquifer parameters.

  7. Analysis of aquifer tests in the Punjab region of West Pakistan

    USGS Publications Warehouse

    Bennett, Gordon D.; ,; Sheikh, Ijaz Ahmed; Alr, Sabire

    1967-01-01

    The results of 141 pumping tests in the Punjab Plain of West Pakistan are reported. Methods of test analysis are described in detail, and an outline of the theory underlying these methods is given. The lateral permeability of the screened interval is given for all tests; the specific yield of the material at water-table depth is given for 1(6 tests; and the vertical permeability of the material between the water table and the top of the screen is given for 14 tests. The lateral permeabilities are predominantly in the range 0.001 to 0.006 cfs per sq ft; the average value is 0.0032 cfs per sq ft. Specific yields generally range from 0.02 to 0.26; the average value is 0.14. All vertical permeability results fall in the range 10 -5 to 10 -3 cfs per sq ft.

  8. Fluorescent dye imaging of the volume sampled by single well forced-gradient tracer tests evaluated in a laboratory-scale aquifer physical model.

    PubMed

    Barns, Gareth L; Wilson, Ryan D; Thornton, Steven F

    2012-02-01

    This study presents a new method to visualise forced-gradient tracer tests in 2-D using a laboratory-scale aquifer physical model. Experiments were designed to investigate the volume of aquifer sampled in vertical dipole flow tracer tests (DFTT) and push-pull tests (PPT), using a miniature monitoring well and straddle packer arrangement equipped with solute injection and recovery chambers. These tests have previously been used to estimate bulk aquifer hydraulic and transport properties for the evaluation of natural attenuation and other remediation approaches. Experiments were performed in a silica glass bead-filled box, using a fluorescent tracer (fluorescein) to deduce conservative solute transport paths. Digital images of fluorescein transport were captured under ultraviolet light and processed to analyse tracer plume geometry and obtain point-concentration breakthrough histories. Inorganic anion mixtures were also used to obtain conventional tracer breakthrough histories. Concentration data from the conservative tracer breakthrough curves was compared with the digital images and a well characterised numerical model. The results show that the peak tracer breakthrough response in dipole flow tracer tests samples a zone of aquifer close to the well screen, while the sampling volume of push-pull tests is limited by the length of the straddle packers used. The effective sampling volume of these single well forced-gradient tests in isotropic conditions can be estimated with simple equations. The experimental approach offers the opportunity to evaluate under controlled conditions the theoretical basis, design and performance of DFTTs and PPTs in porous media in relation to measured flow and transport properties.

  9. Fluorescent dye imaging of the volume sampled by single well forced-gradient tracer tests evaluated in a laboratory-scale aquifer physical model.

    PubMed

    Barns, Gareth L; Wilson, Ryan D; Thornton, Steven F

    2012-02-01

    This study presents a new method to visualise forced-gradient tracer tests in 2-D using a laboratory-scale aquifer physical model. Experiments were designed to investigate the volume of aquifer sampled in vertical dipole flow tracer tests (DFTT) and push-pull tests (PPT), using a miniature monitoring well and straddle packer arrangement equipped with solute injection and recovery chambers. These tests have previously been used to estimate bulk aquifer hydraulic and transport properties for the evaluation of natural attenuation and other remediation approaches. Experiments were performed in a silica glass bead-filled box, using a fluorescent tracer (fluorescein) to deduce conservative solute transport paths. Digital images of fluorescein transport were captured under ultraviolet light and processed to analyse tracer plume geometry and obtain point-concentration breakthrough histories. Inorganic anion mixtures were also used to obtain conventional tracer breakthrough histories. Concentration data from the conservative tracer breakthrough curves was compared with the digital images and a well characterised numerical model. The results show that the peak tracer breakthrough response in dipole flow tracer tests samples a zone of aquifer close to the well screen, while the sampling volume of push-pull tests is limited by the length of the straddle packers used. The effective sampling volume of these single well forced-gradient tests in isotropic conditions can be estimated with simple equations. The experimental approach offers the opportunity to evaluate under controlled conditions the theoretical basis, design and performance of DFTTs and PPTs in porous media in relation to measured flow and transport properties. PMID:22192345

  10. Field Test Report: Preliminary Aquifer Test Characterization Results for Well 299-W15-225: Supporting Phase I of the 200-ZP-1 Groundwater Operable Unit Remedial Design

    SciTech Connect

    Spane, Frank A.; Newcomer, Darrell R.

    2009-09-23

    This report examines the hydrologic test results for both local vertical profile characterization and large-scale hydrologic tests associated with a new extraction well (well 299-W15-225) that was constructed during FY2009 for inclusion within the future 200-West Area Groundwater Treatment System that is scheduled to go on-line at the end of FY2011. To facilitate the analysis of the large-scale hydrologic test performed at newly constructed extraction well 299-W15-225 (C7017; also referred to as EW-1 in some planning documents), the existing 200-ZP-1 interim pump-and-treat system was completely shut-down ~1 month before the performance of the large-scale hydrologic test. Specifically, this report 1) applies recently developed methods for removing barometric pressure fluctuations from well water-level measurements to enhance the detection of hydrologic test and pump-and-treat system effects at selected monitor wells, 2) analyzes the barometric-corrected well water-level responses for a preliminary determination of large-scale hydraulic properties, and 3) provides an assessment of the vertical distribution of hydraulic conductivity in the vicinity of newly constructed extraction well 299-W15-225. The hydrologic characterization approach presented in this report is expected to have universal application for meeting the characterization needs at other remedial action sites located within unconfined and confined aquifer systems.

  11. Chemical analysis of water samples and geophysical logs from cored test holes drilled in the central Oklahoma Aquifer, Oklahoma

    USGS Publications Warehouse

    Schlottmann, Jamie L.; Funkhouser, Ron A.

    1991-01-01

    Chemical analyses of water from eight test holes and geophysical logs for nine test holes drilled in the Central Oklahoma aquifer are presented. The test holes were drilled to investigate local occurrences of potentially toxic, naturally occurring trace substances in ground water. These trace substances include arsenic, chromium, selenium, residual alpha-particle activities, and uranium. Eight of the nine test holes were drilled near wells known to contain large concentrations of one or more of the naturally occurring trace substances. One test hole was drilled in an area known to have only small concentrations of any of the naturally occurring trace substances. Water samples were collected from one to eight individual sandstone layers within each test hole. A total of 28 water samples, including four duplicate samples, were collected. The temperature, pH, specific conductance, alkalinity, and dissolved-oxygen concentrations were measured at the sample site. Laboratory determinations included major ions, nutrients, dissolved organic carbon, and trace elements (aluminum, arsenic, barium, beryllium, boron, cadmium, chromium, hexavalent chromium, cobalt, copper, iron, lead, lithium, manganese, mercury, molybdenum, nickel, selenium, silver, strontium, vanadium, and zinc). Radionuclide activities and stable isotope d values also were determined, including: gross-alpha-particle activity, gross-beta-particle activity, radium-226, radium-228, radon-222, uranium-234, uranium-235, uranium-238, total uranium, carbon-13/carbon-12, deuterium/hydrogen-1, oxygen-18/oxygen-16, and sulfur-34/sulfur-32. Additional analyses of arsenic and selenium species are presented for selected samples as well as analyses of density and iodine for two samples, tritium for three samples, and carbon-14 for one sample. Geophysical logs for most test holes include caliper, neutron, gamma-gamma, natural-gamma logs, spontaneous potential, long- and short-normal resistivity, and single-point resistance

  12. Migration of conservative and sorbing radionuclides in heterogeneous fractured rock aquifers at the Nevada Test Site

    NASA Astrophysics Data System (ADS)

    Boryta, J. R.; Wolfsberg, A. V.

    2003-12-01

    The Nevada Test Site (NTS) is the United States continental nuclear weapons testing site. The larger underground tests, including BENHAM and TYBO, were conducted at Pahute Mesa. The BENHAM test, conducted in 1968, was detonated 1.4 km below the surface and the TYBO test, conducted in 1975, was detonated at a depth of 765 m. Between 1996 and 1998, several radionuclides were discovered in trace concentrations in a monitoring well complex 273 m from TYBO and 1300 m from BENHAM. Previous studies associated with these measurements have focused primarily on a) plutonium discovered in the observation wells, which was identified through isotopic finger printing as originating at BENHAM, b) colloid-facilitated plutonium transport processes, and c) vertical convection in subsurface nuclear test collapse chimneys. In addition to plutonium, several other non-, weakly-, and strongly-sorbing radionuclides were discovered in trace concentrations in the observation wells, including tritium, carbon-14, chlorine-36, iodine-129, technetium-99, neptunium-237, strontium-90, cesium-137, americium-241, and europium-152,154,155. The range in retardation processes affecting these different radionuclides provides additional information for assessing groundwater solute transport model formulations. For all radionuclides, simulation results are most sensitive to the fracture porosity and fracture aperture. Additionally, for weakly sorbing Np, simulation results are highly sensitive to the matrix sorption coefficient. For strongly sorbing species, migration in the absence of colloids can only be simulated if fracture apertures are set very large, reducing the amount of diffusion that can occur. For these species, colloid-facilitated transport appears to be a more likely explanation for the measurements. This is corroborated with colloid-transport model simulations.

  13. Application of tracer injection tests to characterize rock matrix block size distribution and dispersivity in fractured aquifers

    NASA Astrophysics Data System (ADS)

    Sharifi Haddad, Amin; Hassanzadeh, Hassan; Abedi, Jalal; Chen, Zhangxin

    2014-03-01

    The complexity of mass transfer processes between the mobile and immobile zones in geohydrologic settings and the limitations that currently exist in the characterization of contaminated sites demand the development of improved models. In this work, we present a model that describes the mass transfer in structured porous media. This model considers divergent radial advective-dispersive transport in fractures and diffusive mass transfer inside rock matrix blocks. The heterogeneous nature of fractured formations is included with the integration of various distributions of rock matrix block sizes into the transport model. Breakthrough curves generated based on the developed model are analyzed to investigate the effects of the rate of injection, dispersivity and the immobile to mobile porosity ratio on mass transfer between mobile and immobile zones. It is shown that the developed model, in conjunction with tracer data collected from a monitoring well, can be used to estimate the dispersivity and fracture intensity. Results reveal that the dispersivity is independent of the rock matrix block size distribution for dispersion-dominant transport in fractures. These findings are used to develop a methodology to characterize rock matrix block size distribution in fractured aquifers and to estimate dispersivity based on a tracer test, which will improve our decisions concerning the remediation of contaminated sites.

  14. Characterization of 200-UP-1 Aquifer Sediments and Results of Sorption-Desorption Tests Using Spiked Uncontaminated Groundwater

    SciTech Connect

    Um, Wooyong; Serne, R JEFFREY.; Bjornstad, Bruce N.; Schaef, Herbert T.; Brown, Christopher F.; Legore, Virginia L.; Geiszler, Keith N.; Baum, Steven R.; Valenta, Michelle M.; Kutnyakov, Igor V.; Vickerman, Tanya S.; Lindberg, Michael J.

    2005-11-16

    of carbonate up to a point. Then as carbonate and calcium concentrations in the groundwater reach values that exceed the solubility limit for the mineral calcite there is a slight increase in U(VI) Kd likely caused by uranium co-precipitation with the fresh calcite. If remediation of the UP-1 groundwater plume is required, such as pump and treat, it is recommended that the aquifer be treated with chemicals to increase pH and alkalinity and decrease dissolved calcium and magnesium [so that the precipitation of calcite is prevented]. Alternative methods to immobilize the uranium in place might be more effective than trying to remove the uranium by pump and treat. Unfortunately, no aquifer sediments were obtained that contained enough Hanford generated uranium to perform quantitative desorption tests germane to the UP-1 plume remediation issue. Recommended Kd values that should be used for risk predictions for the UP-1 groundwater plume traveling through the lithologies within the aquifer present at the UP-1 (and by proxy ZP-1) operable units were provided. The recommended values Kd values are chosen to include some conservatism (lower values are emphasized from the available range) as is standard risk assessment practice. In general, desorption Kd values for aged contaminated sediments can be larger than Kd values determined in short-term laboratory experiments. To accommodate the potential for desorption hysteresis and other complications, a second suite of uranium desorption Kd values were provided to be used to estimate removal of uranium by pump and treat techniques.

  15. Summary of hydrologic testing in Tertiary limestone aquifer, Tenneco offshore exploratory well--Atlantic OCS, lease-block 427 (Jacksonville NH 17-5)

    USGS Publications Warehouse

    Johnston, Richard H.; Bush, Peter W.; Krause, Richard E.; Miller, James A.; Sprinkle, Craig L.

    1982-01-01

    A summary of hydrologic testing in an offshore oil-test well (LB427) drilled for Tenneco, Inc., 55 miles east of Fernandina Beach, Florida, is presented. The interval tested (1,050 to 1,070 feet below sea level) is in a calcarenite that is equivalent to the Ocala Limestone (late Eocene) of onshore Florida and South Georgia. At this site the Ocala forms the highly productive Tertiary limestone aquifer system of the southeastern United States. Pressure-head measurements indicate an equivalent freshwater head of 24 to 29 feet above sea level. These pressure-head measurements and an earlier one made in the nearby JOIDES J- I hole are the only hydraulic head determinations to date in the offshore extensions of any of the aquifers underlying the Atlantic coastal plain. A drill-stem test recovered water samples containing about 7,000 milligrams per liter chloride. However, seawater used in the drilling process apparently contaminated the samples and the formation water is considered slightly fresher. The head and salinity data from the Tenneco well suggest that the sampled interval lies in the transition zone between fresh and seawater in the limestone aquifer. These data, when viewed with similar data from JOIDES J-I, show the transition zone to slope very slightly landward. The interface position is probably intermediate between a position compatible with present-day heads and a position compatible with predevelopment heads.

  16. Conditioning geostatistical simulations of a bedrock fluvial aquifer using single well pumping tests

    NASA Astrophysics Data System (ADS)

    Niazi, A.; Bentley, L. R.; Hayashi, M.

    2015-12-01

    Geostatistical simulation is a powerful tool to explore the uncertainty associated with heterogeneity in groundwater and reservoir studies. Nonetheless, conditioning simulations merely with lithological information does not utilize all of the available information and so some workers additionally condition simulations with flow data. In this study, we introduce an approach to condition geostatistical simulations of the Paskapoo Formation, which is a paleo-fluvial system consisting of sandstone channels embedded in mudstone. The conditioning data consist of two-hour single well pumping tests extracted from the public water well database in Alberta, Canada. In this approach, lithologic models of an entire watershed are simulated and conditioned with hard lithological data using transition probability geostatistics (TPROGS). Then, a segment of the simulation around a pumping well was used to populate a flow model (FEFLOW) with either sand or mudstone. The values of the hydraulic conductivity and specific storage of sand and mudstone were then adjusted to minimize the difference between simulated and actual pumping test data using the parameter estimation program PEST. If the simulated data do not adequately match the measured data, the lithologic model is updated by locally deforming the lithology distribution using the probability perturbation method (PPM) and the model parameters are again updated with PEST. This procedure is repeated until the simulated and measured data agree within a pre-determined tolerance. The procedure is repeated for each pumping well that has pumping test data. The method constrains the lithological simulations and provides estimates of hydraulic conductivity and specific storage that are consistent with the pumping test data. Eventually, the simulations will be combined in watershed scale groundwater models.

  17. Exploratory drilling and aquifer testing at the Kipahulu District, Haleakala National Park, Maui, Hawaii

    USGS Publications Warehouse

    Souza, W.R.

    1983-01-01

    An exploratory well, located at 388 feet above sea level in Kipahulu Valley on Maui, Hawaii, was completed and tested in October 1980. The 410-foot well penetrates a series of very dense basaltic lava flows of the Hana Formation. At an elevation of 10 feet above mean sea level, the well penetrated a water-bearing zone of permeable basaltic rock. Water from this zone had a head of about 76 feet above sea level. In October of 1980, the well was pump tested for 9 hours at various discharge rates up to 350 gallons per minute with a maximum drawdown of about 12 feet. Based on the test data, the well should produce water at a rate of 200 gallons per minute with a drawdown of less than 3 feet. The water level in the well was continuously monitored from October 1980 to mid-November 1981, during which period a maximum decline of 20 feet was recorded. Water level fluctuations in the well can be correlated to the flow in nearby Palikea Stream. The long-term water level in the well should stabilize at about 75 feet above sea level. Water quality was excellent. The total dissolved-solids content was 49 milligrams per liter and the chloride content was 4.2 milligrams per liter. (USGS)

  18. Steady shape analysis of tomographic pumping tests for characterization of aquifer heterogeneities

    USGS Publications Warehouse

    Bohling, G.C.; Zhan, X.; Butler, J.J.; Zheng, Lingyun

    2002-01-01

    Hydraulic tomography, a procedure involving the performance of a suite of pumping tests in a tomographic format, provides information about variations in hydraulic conductivity at a level of detail not obtainable with traditional well tests. However, analysis of transient data from such a suite of pumping tests represents a substantial computational burden. Although steady state responses can be analyzed to reduce this computational burden significantly, the time required to reach steady state will often be too long for practical applications of the tomography concept. In addition, uncertainty regarding the mechanisms driving the system to steady state can propagate to adversely impact the resulting hydraulic conductivity estimates. These disadvantages of a steady state analysis can be overcome by exploiting the simplifications possible under the steady shape flow regime. At steady shape conditions, drawdown varies with time but the hydraulic gradient does not. Thus transient data can be analyzed with the computational efficiency of a steady state model. In this study, we demonstrate the value of the steady shape concept for inversion of hydraulic tomography data and investigate its robustness with respect to improperly specified boundary conditions.

  19. Lithologic properties of carbonate-rock aquifers at five test wells in the Coyote Spring Valley Area, southern Nevada, as determined from geophysical logs. Water resources investigation report

    SciTech Connect

    Berger, D.L.

    1992-01-01

    Regional ground-water flow systems in the carbonate-rock aquifers in southern Nevada were evaluated as potential sources for water supply as part of the Nevada Carbonate Aquifers Program. Geophysical log analyses indicated that the test wells penetrate carbonate rocks, which vary in composition from limestone to dolomite and include mixtures of both. Calcite was found to be the predominant matrix mineral and shales made up of only a small percentage of the overall rock. Bulk-density measurements averaged 2.65 grams per cubic centimeter and the matrix density estimates averaged 2.76 grams per cubic centimeter. Increased amounts of silica in the matrix mineralogy were associated with greater total porosity values. The log analyses indicated an average of 4.7 percent porosity for 43 zones in the test wells.

  20. Drilling, construction, and aquifer-test data from wells 3-3307-20 and -21, Thompson Corner exploratory wells I and II, Oahu, Hawaii

    USGS Publications Warehouse

    Presley, T.K.; Oki, D.S.

    1996-01-01

    The Thompson Corner exploratory wells I and II (State well numbers 3-3307-20 and -21) were drilled near Thompson Corner, about 2.2 miles south-southwest of the town of Haleiwa. The wells are located on agricultural land in the Waialua ground-water area. The wells are about 50 feet apart and penetrate about 90 feet into the ground water. Aquifer tests were conducted using well 3-3307-20 as a pumping well and well 3-3307-21 as an observation well. Well-construction data, logs of drilling notes, geologic descriptions for the samples, and aquifer-test data are presented for the wells. The wells are two of twelve exploratory wells drilled in the north-central Oahu area between July 1993 and May 1994 in cooperation with the Honolulu Board of Water Supply.

  1. Batch-test study on the dechlorination of 1,1,1-trichloroethane in contaminated aquifer material by zero-valent iron.

    PubMed

    Lookman, Richard; Bastiaens, Leen; Borremans, Brigitte; Maesen, Miranda; Gemoets, Johan; Diels, Ludo

    2004-10-01

    Chlorinated aliphatic hydrocarbons are common groundwater contaminants. One possible remediation option is in-situ reductive dechlorination by zero-valent iron, either by direct injection or as reactive barriers. Chlorinated ethenes (tetrachloroethene: PCE; trichloroethene: TCE) have received extensive attention in this context. However, another common groundwater pollutant, 1,1,1-trichlorethane (TCA), has attracted much less attention. We studied TCA reduction by three types of granular zero-valent irons in a series of batch experiments using polluted groundwater, with and without added aquifer material. Two types of iron were able to reduce TCA completely with no daughter product concentration increases (1,1-dichloroethane: DCA; chloroethane: CA). One type of iron showed slower reduction, with intermediate rise of DCA and CA concentrations. When evaluating the formation of daughter products, the tests on the groundwater alone showed different results than the groundwater plus aquifer batches: DCA did not temporarily accumulate in the batches with added aquifer material, contrary to the batches without added aquifer material. 1,1-dichloroethene (DCE, also present in the groundwater as an abiotic degradation product of TCA) was also reduced slower in the batches without added aquifer material than in the batches with aquifer material. Redox potentials gradually decreased to low values in batches with aquifer material without iron, while the batches with groundwater alone maintained a constant higher redox potential. Either adsorption processes or microbiological activity in the samples could explain these phenomena. Polymerase Chain Reaction (PCR: a targeted gene probe technique) for chlorinated aliphatic compound (CAH)-degrading bacteria confirmed the presence of Dehalococcoides sp. (chloroethene-degraders) but was negative for Desulfobacterium autotrophicum (a known co-metabolic TCA degrader). DCA reduction was rate determining: first-order half-lives of 300

  2. Geophysical Logs, Aquifer Tests, and Water Levels in Wells in and Near the North Penn Area 7 Superfund Site, Upper Gwynedd Township, Montgomery County, Pennsylvania, 2002-2006

    USGS Publications Warehouse

    Senior, Lisa A.; Conger, Randall W.; Bird, Philip H.

    2008-01-01

    Ground water in the vicinity of several industrial facilities in Upper Gwynedd Township and Lansdale Borough, Montgomery County, Pa., is contaminated with several volatile organic compounds (VOCs). 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, water-level monitoring, and streamflow measurements in the vicinity of North Penn Area 7 from October 2002 through December 2006. This followed work that began in 2000 to assist the USEPA in developing an understanding of the hydrogeologic framework in the area as part of the USEPA Remedial Investigation. The study area is underlain by Triassic- and Jurassic-age sandstones, siltstones, and shales of the Lockatong Formation and the Brunswick Group. Regionally, these rocks strike northeast and dip to the northwest. The sequence of rocks form fractured-rock aquifers that act as a set of confined to semi-confined layered aquifers of differing permeabilities. The aquifers are recharged by precipitation and discharge to streams and wells. The Wissahickon Creek headwaters are less than 1 mile northeast of the study area. This stream flows southwest approximately parallel to strike and bisects North Penn Area 7. Ground water is pumped in the vicinity of North Penn Area 7 for industrial use and public supply. The USGS collected geophysical logs for 42 wells that ranged in depth from 40 to 477 ft. Aquifer-interval-isolation testing was done in 17 of the 42 wells, for a total of 122 zones tested. A multiple-well aquifer test was conducted by monitoring the response of 14 wells to pumping and shutdown of a 600-ft deep production well in November-December 2004. In addition, water levels were monitored continuously in four wells in the area from October 2002 through September 2006, and streamflow was measured quarterly at two sites on

  3. Equilibrium geochemical modeling of a seasonal thermal energy storage aquifer field test

    NASA Technical Reports Server (NTRS)

    Stottlemyre, J. S.

    1980-01-01

    A geochemical mathematical modeling study designed to investigate the well plugging problems encountered at the Auburn University experimental field tests is summarized. The results, primarily of qualitative interest, include: (1) loss of injectivity was probably due to a combination of native particulate plugging and clay swelling and dispersion; (2) fluid-fluid incompatibilities, hydrothermal reactions, and oxidation reactions were of insignificant magnitude or too slow to have contributed markedly to the plugging; and (3) the potential for and contributions from temperature-induced dissolved gas solubility reductions, capillary boundary layer viscosity increases, and microstructural deformation cannot be deconvolved from the available data.

  4. Modeling slug tests in unconfined aquifers with both oscillatory and overdamped responses, and with low-K and high-K skin effects

    NASA Astrophysics Data System (ADS)

    Thoma, M. J.; Malama, B.; Barrash, W.; Bohling, G.; Butler, J. J.

    2009-12-01

    We extend the models for slug tests developed by Hyder et al. (1994) and Butler and Zhan (2004) to obtain a single general model for slug tests in unconfined aquifers in partially penetrating wells with a near-well disturbed zone (skin). The full range of responses, oscillatory to overdamped, is considered since both types of responses are common in wells in unconsolidated coarse fluvial aquifers, and others. The general semi-analytical solution allows for skin and formation storage as well as anisotropy in skin and formation hydraulic conductivity (K). The water table is treated as a fixed head boundary so the solution is applicable for wells screened below the water table. The model is validated by comparison with other models and by matching field data from unconfined fluvial aquifers at sites in Nebraska (MSEA) and Idaho (BHRS). We examine the effects of varying skin K and skin thickness to simulate the impact of a near-well disturbed zone that is lower (damage) or higher (filter pack) K than the formation. Results indicate that, for a given set of measured behavior at an example test zone, minor progressive decreases in estimated formation K occur with increases in assumed skin K, and moderate increases in estimated formation K occur with decreases in assumed skin K. Major increases (orders of magnitude) in estimated formation K occur with increased thickness of low-K skin. The importance of incorporating a finite-thickness representation of the skin, rather than the conventional infinitely thin representation, is also addressed.

  5. Investigations on mobility of carbon colloid supported nanoscale zero-valent iron (nZVI) in a column experiment and a laboratory 2D-aquifer test system.

    PubMed

    Busch, Jan; Meißner, Tobias; Potthoff, Annegret; Oswald, Sascha E

    2014-09-01

    Nanoscale zero-valent iron (nZVI) has recently gained great interest in the scientific community as in situ reagent for installation of permeable reactive barriers in aquifer systems, since nZVI is highly reactive with chlorinated compounds and may render them to harmless substances. However, nZVI has a high tendency to agglomerate and sediment; therefore it shows very limited transport ranges. One new approach to overcome the limited transport of nZVI in porous media is using a suited carrier colloid. In this study we tested mobility of a carbon colloid supported nZVI particle "Carbo-Iron Colloids" (CIC) with a mean size of 0.63 μm in a column experiment of 40 cm length and an experiment in a two-dimensional (2D) aquifer test system with dimensions of 110 × 40 × 5 cm. Results show a breakthrough maximum of 82 % of the input concentration in the column experiment and 58 % in the 2D-aquifer test system. Detected residuals in porous media suggest a strong particle deposition in the first centimeters and few depositions in the porous media in the further travel path. Overall, this suggests a high mobility in porous media which might be a significant enhancement compared to bare or polyanionic stabilized nZVI.

  6. Large-Scale Aquifer Test at the Bemidji, Minnesota, Oil-Spill Site: Implications for Modeling Multiphase Flow, Natural Attenuation, and LNAPL Remediation

    NASA Astrophysics Data System (ADS)

    Herkelrath, W. N.; Delin, G. N.

    2005-12-01

    A large-scale aquifer test was carried out at a crude oil spill site near Bemidji, Minnesota. The spill occurred in 1979 when a pipeline ruptured, spreading oil over a large area and creating three subsurface "pools" of high oil saturation near the water table. USGS scientists, in cooperation with researchers from several universities, have investigated the fate and transport of separate phase oil and hydrocarbons dissolved in ground water at this site since 1983. The primary goal of the aquifer test was to estimate parameters used in modeling processes such as subsurface flow of oil and water as well as natural attenuation of dissolved hydrocarbons in the plume. A secondary goal was to evaluate the effects of the oil on the parameters. Our aquifer test was carried out in July 2005 beneath the "north" oil pool, which occupies a 20x100 meter footprint. Prior to the test, the water table was about 6 meters below land surface, and the oil thickness in wells at the center of the pool was about 0.4 meters. A pumping well was installed near the center of the oil pool and screened 4-10 meters below the floating oil. During the test, water was pumped out at about 240 liters/min for 48 hours. Water levels were monitored in 21 wells that were screened below the water table and did not contain oil. Data loggers and pressure transducers were used to monitor 17 of these wells, and 4 wells were measured by hand using a tape. In 20 other wells that were screened at the water table and contained oil, depths to the oil-air and oil-water interfaces were monitored by hand using an oil-interface meter. Preliminary results indicate that oil thickness in wells within about 5 meters of the pumped well increased rapidly during the test to more than a meter. Oil also entered the top of the pumped well screen and filled the well bore to a thickness of about 3 meters. Preliminary analysis of water table drawdown vs. time data implies that the horizontal hydraulic conductivity is about 60 m

  7. Groundwater flow characterization in a fractured bedrock aquifer using active DTS tests in sealed boreholes

    NASA Astrophysics Data System (ADS)

    Coleman, Thomas I.; Parker, Beth L.; Maldaner, Carlos H.; Mondanos, Michael J.

    2015-09-01

    In recent years, wireline temperature profiling methods have evolved to offer new insight into fractured rock hydrogeology. Important advances in wireline temperature logging in boreholes make use of active line source heating alone and then in combination with temporary borehole sealing with flexible impervious fabric liners to eliminate the effects of borehole cross-connection and recreate natural flow conditions. Here, a characterization technique was developed based on combining fiber optic distributed temperature sensing (DTS) with active heating within boreholes sealed with flexible borehole liners. DTS systems provide a temperature profiling method that offers significantly enhanced temporal resolution when compared with conventional wireline trolling-based techniques that obtain a temperature-depth profile every few hours. The ability to rapidly and continuously collect temperature profiles can better our understanding of transient processes, allowing for improved identification of hydraulically active fractures and determination of relative rates of groundwater flow. The advantage of a sealed borehole environment for DTS-based investigations is demonstrated through a comparison of DTS data from open and lined conditions for the same borehole. Evidence for many depth-discrete active groundwater flow features under natural gradient conditions using active DTS heat pulse testing is presented along with high resolution geologic and geophysical logging and hydraulic datasets. Implications for field implementation are discussed.

  8. Evaluation of sulfate reduction at experimentally induced mixing interfaces using small-scale push-pull tests in an aquifer-wetland system

    USGS Publications Warehouse

    Kneeshaw, T.A.; McGuire, J.T.; Smith, E.W.; Cozzarelli, I.M.

    2007-01-01

    This paper presents small-scale push-pull tests designed to evaluate the kinetic controls on SO42 - reduction in situ at mixing interfaces between a wetland and aquifer impacted by landfill leachate at the Norman Landfill research site, Norman, OK. Quantifying the rates of redox reactions initiated at interfaces is of great interest because interfaces have been shown to be zones of increased biogeochemical transformations and thus may play an important role in natural attenuation. To mimic the aquifer-wetland interface and evaluate reaction rates, SO42 --rich anaerobic aquifer water (??? 100 mg / L SO42 -) was introduced into SO42 --depleted wetland porewater via push-pull tests. Results showed SO42 - reduction was stimulated by the mixing of these waters and first-order rate coefficients were comparable to those measured in other push-pull studies. However, rate data were complex involving either multiple first-order rate coefficients or a more complex rate order. In addition, a lag phase was observed prior to SO42 - reduction that persisted until the mixing interface between test solution and native water was recovered, irrespective of temporal and spatial constraints. The lag phase was not eliminated by the addition of electron donor (acetate) to the injected test solution. Subsequent push-pull tests designed to elucidate the nature of the lag phase support the importance of the mixing interface in controlling terminal electron accepting processes. These data suggest redox reactions may occur rapidly at the mixing interface between injected and native waters but not in the injected bulk water mass. Under these circumstances, push-pull test data should be evaluated to ensure the apparent rate is actually a function of time and that complexities in rate data be considered. ?? 2007 Elsevier Ltd. All rights reserved.

  9. Theory of aquifer tests

    USGS Publications Warehouse

    Ferris, J.G.; Knowles, D.B.; Brown, R.H.; Stallman, R.H.

    1962-01-01

    The development of water supplies from wells was placed on a rational basis with Darcy's development of the law governing the movement of fluids through sands and with Dupuit's application of that law to the problem of radial flow toward a pumped well. As field experience increased, confidence in the applicability of quantitative methods was gained and interest in developing solutions for more complex hydrologic problems was stimulated. An important milestone was Theis' development in 1935 of a solution for the nonsteady flow of ground water, which enabled hydrologists for the first time to predict future changes in ground-water levels resulting from pumping or recharging of wells. In the quarter century since, quantitative ground-water hydrology has been enlarging so rapidly as to discourage the preparation of comprehensive textbooks. This report surveys developments in fluid mechanics that apply to groundwater hydrology. It emphasizes concepts and principles, and the delineation of limits of applicability of mathematical models for analysis of flow systems in the field. It stresses the importance of the geologic variable and its role in governing the flow regimen. The report discusses the origin, occurrence, and motion of underground water in relation to the development of terminology and analytic expressions for selected flow systems. It describes the underlying assumptions necessary for mathematical treatment of these flow systems, with particular reference to the way in which the assumptions limit the validity of the treatment.

  10. Approaches to Quantify Potential Contaminant Transport in the Lower Carbonate Aquifer from Underground Nuclear Testing at Yucca Flat, Nevada National Security Site, Nye County, Nevada - 12434

    SciTech Connect

    Andrews, Robert W.; Birdie, Tiraz; Wilborn, Bill; Mukhopadhyay, Bimal

    2012-07-01

    Quantitative modeling of the potential for contaminant transport from sources associated with underground nuclear testing at Yucca Flat is an important part of the strategy to develop closure plans for the residual contamination. At Yucca Flat, the most significant groundwater resource that could potentially be impacted is the Lower Carbonate Aquifer (LCA), a regionally extensive aquifer that supplies a significant portion of the water demand at the Nevada National Security Site, formerly the Nevada Test Site. Developing and testing reasonable models of groundwater flow in this aquifer is an important precursor to performing subsequent contaminant transport modeling used to forecast contaminant boundaries at Yucca Flat that are used to identify potential use restriction and regulatory boundaries. A model of groundwater flow in the LCA at Yucca Flat has been developed. Uncertainty in this model, as well as other transport and source uncertainties, is being evaluated as part of the Underground Testing Area closure process. Several alternative flow models of the LCA in the Yucca Flat/Climax Mine CAU have been developed. These flow models are used in conjunction with contaminant transport models and source term models and models of contaminant transport from underground nuclear tests conducted in the overlying unsaturated and saturated alluvial and volcanic tuff rocks to evaluate possible contaminant migration in the LCA for the next 1,000 years. Assuming the flow and transport models are found adequate by NNSA/NSO and NDEP, the models will undergo a peer review. If the model is approved by NNSA/NSO and NDEP, it will be used to identify use restriction and regulatory boundaries at the start of the Corrective Action Decision Document Corrective Action Plan (CADD/CAP) phase of the Corrective Action Strategy. These initial boundaries may be revised at the time of the Closure Report phase of the Corrective Action Strategy. (authors)

  11. Stratigraphy of the unsaturated zone and uppermost part of the Snake River Plain aquifer at test area north, Idaho National Engineering Laboratory, Idaho

    SciTech Connect

    Anderson, S.R.; Bowers, B.

    1995-06-01

    A complex sequence of basalt flows and sedimentary interbeds underlies Test Area North (TAN) at the Idaho National Engineering Laboratory in eastern Idaho. Wells drilled to depths of at least 500 feet penetrate 10 basalt-flow groups and 5 to 10 sedimentary interbeds that range in age from about 940,000 to 1.4 million years. Each basalt-flow group consists of one or more basalt flows from a brief, single or compound eruption. All basalt flows of each group erupted from the same vent, and have similar ages, paleomagnetic properties, potassium contents, and natural-gamma emissions. Sedimentary interbeds consist of fluvial, lacustrine, and eolian deposits of clay, silt, sand, and gravel that accumulated for hundreds to hundreds of thousands of years during periods of volcanic quiescence. Basalt and sediment are elevated by hundreds of feet with respect to rocks of equivalent age south and cast of the area, a relation that is attributed to past uplift at TAN. Basalt and sediment are unsaturated to a depth of about 200 feet below land surface. Rocks below this depth are saturated and make up the Snake River Plain aquifer. The effective base of the aquifer is at a depth of 885 feet below land surface. Detailed stratigraphic relations for the lowermost part of the aquifer in the depth interval from 500 to 885 feet were not determined because of insufficient data. The stratigraphy of basalt-flow groups and sedimentary interbeds in the upper 500 feet of the unsaturated zone and aquifer was determined from natural-gamma logs, lithologic logs, and well cores. Basalt cores were evaluated for potassium-argon ages, paleomagnetic properties, petrographic characteristics, and chemical composition. Stratigraphic control was provided by differences in ages, paleomagnetic properties, potassium content, and natural-gamma emissions of basalt-flow groups and sedimentary interbeds.

  12. AQUIFER TRANSMISSIVITY

    EPA Science Inventory

    Evaluation of groundwater resources requires the knowledge of the capacity of aquifers to store and transmit ground water. This requires estimates of key hydraulic parameters, such as the transmissivity, among others. The transmissivity T (m2/sec) is a hydrauli...

  13. Multitracer test for the determination of transport and in-situ degradation of organic micro-contaminants in karst aquifers on the example of caffeine

    NASA Astrophysics Data System (ADS)

    Hillebrand, O.; Nödler, K.; Licha, T.; Geyer, T.

    2012-04-01

    The application of organic micro-contaminants as indicators for contamination sources in aquifers and surface-water bodies has been increasingly discussed in the literature over the last years. One of the proposed substances was caffeine. It served as indicator for wastewater-leakage to various systems. As well, wastewater volumes could be estimated from caffeine concentrations. Although caffeine is known to be degradable, the degradation rates are normally only determined from mass balances or laboratory experiments. Degradation rates obtained from mass balances are relatively uncertain, as the input-function is difficult to be assessed. Laboratory experiments are hardly capable to consider the full complexity of natural systems and can rarely be transferred to those. To solve this problem, in-situ degradation rates of reactive indicators have to be determined. Especially multitracer tests can be used to access compound-specific transport parameters and degradation rates, relative to conservative tracers. A multitracer test with caffeine and uranine has been performed in a karst system (catchment of the Gallusquelle spring, SW Germany). From the breakthrough curves of the tracers, the transport behavior and the in-situ degradation rate of caffeine could be deduced. The tracers were injected into a sinkhole with a linear distance of 3000 m to the spring. The mean residence time of the tracers was found to be 84 h at a flow velocity of 35 m/h. Throughout the whole experiment, the spring discharge was constant at 187 L/s. Uranine served as conservative reference-tracer for the calibration of a one-dimensional transport model with respect to solute-unspecific parameters. Relative to that, the tracer breakthrough curve of caffeine was interpreted. As solute-specific parameters the retardation coefficient as well as degradation rate of caffeine in the investigated karst aquifer could be determined. The results indicate, that caffeine is slightly retarded in the

  14. Response to Comment by H. Lough, Department of Civil Engineering, University of Canterbury, Christchurch, New Zealand, on the Paper " Stream Depletion Predictions using Pumping Test Data from A Heterogeneous Stream-Aquifer System (A Case Study from the Gr

    SciTech Connect

    Kollet, S J; Zlotnik, V A

    2004-12-20

    We thank H. Lough for her interest in our data set and the attempt to re-analyze our results (Kollet and Zlotnik, 2003) using the recent model by Hunt (2003). We welcome others to share our unique data set of the pumping test from the Prairie Creek site, Nebraska, USA. Nevertheless we believe that this particular attempt failed, because H. Lough selected a wrong model of semi-confined aquifer conditions for the interpretation of the pumping test data, which was collected in an unconfined aquifer. H. Lough based her selection on the three distinct drawdown segments observed during the test. It is well known that geologically distinct aquifers can yield a three-segment drawdown response under pumping conditions (e.g., Streltsova, 1988). Examples include unconfined aquifers (e.g., Neuman, 1972; Moench, 1997), aquifers with double porosity or fractures (e.g., Barenblatt et al., 1960; Boulton and Streltsova-Adams, 1978), and (semi-) confined aquifers in contact with aquitards (e.g. Cooley and Case, 1973; Moench, 1985). At the Prairie Creek site the aquifer is unconfined. The interpretation of the pumping test data collected at the site using type curves that are valid for an aquifer-aquitard system is a mistake. In fact, this approach illustrates a typical problem associated with inverse modeling: drastically different models can closely reproduce a system response and yield some parameter estimates, although the models do not represent the real system adequately. Here, the improper model yields some parameter estimates for an aquitard, although the aquitard does not exist at the Prairie Creek test site. We must also unequivocally state that the model by Hunt (2003) is clearly formulated and correct for stream-aquifer-aquitard systems within the stated limitations (pumping wells screened only in the lowest stratigraphic layer, etc.). However, the Hunt (1999) or BZT (Butler et al., 2001) models should be used for interpreting pumping tests near streams in non

  15. Hydrogeology and water quality of the Floridan aquifer system and effect of Lower Floridan aquifer pumping on the Upper Floridan aquifer at Hunter Army Airfield, Chatham County, Georgia

    USGS Publications Warehouse

    Clarke, John S.; Williams, Lester J.; Cherry, Gregory C.

    2010-01-01

    liter (mg/L), respectively. These relatively high concentrations were interpreted to have little effect on the overall quality of the well because flowmeter results indicated that water from 1,060 to 1,080 ft contributed less than 2 percent of the total flow to the completed well. Results of a 72-hour aquifer test indicate that pumping a LFA well at a rate of 748 gal/min produced a drawdown response of 0.76 ft in a well completed in the UFA located 176 ft from the pumped well. A revised regional groundwater-flow model was used to simulate long-term (steady-state) leakage response of the UFA to pumping from the LFA and to estimate the equivalent amount of pumping from the UFA that would produce similar drawdown. Pumping the well at a rate of 748 gal/min (about 1 million gallons per day [Mgal/d]) resulted in a maximum simulated steady-state drawdown of 36.2 ft in the LFA and was greater than 1 ft over a 146 square-mile area. Simulated steady-state drawdown in the overlying UFA that resulted from interaquifer leakage was greater than 1 ft over a 141 square-mile area and was 2.03 ft at the pumped well. Flow to the pumped well was derived from increased lateral flow across the specified-head boundary (0.02 Mgal/d) and increased leakage from the UFA (0.52 Mgal/d), and by reductions in discharge to the Lower Floridan confining unit (0.53 Mgal/d) and to the lateral specified-head boundary (0.53 Mgal/d). Sixty-five percent of the leakage from the UFA occurred within 1 mile of the pumped well. This larger contribution results from a larger head gradient between the pumped well and the overlying aquifer in areas close to the pumped well. The Georgia Environmental Protection Division interim permitting strategy for the LFA requires simulation of (1) aquifer leakage from the UFA to LFA resulting from pumping the new LFA well, and (2) the equivalent rate of UFA pumping that induces the identical maximum drawdown in the UFA that would be expected as a result of pumping th

  16. The in-situ decontamination of sand and gravel aquifers by chemically enhanced solubilization of multiple-compound DNAPLs with surfactant solutions: Phase 1 -- Laboratory and pilot field-scale testing and Phase 2 -- Solubilization test and partitioning and interwell tracer tests. Final report

    SciTech Connect

    1997-10-24

    Laboratory, numerical simulation, and field studies have been conducted to assess the potential use of micellar-surfactant solutions to solubilize chlorinated solvents contaminating sand and gravel aquifers. Ninety-nine surfactants were screened for their ability to solubilize trichloroethene (TCE), perchloroethylene (PCE), and carbon tetrachloride (CTET). The field test was conducted in the alluvial aquifer which is located 20 to 30 meters beneath a vapor degreasing operation at Paducah Gaseous Diffusion Plant. This aquifer has become contaminated with TCE due to leakage of perhaps 40,000 liters of TCE, which has generated a plume of dissolved TCE extending throughout an area of approximately 3 km{sup 2} in the aquifer. Most of the TCE is believed to be present in the overlying lacustrine deposits and in the aquifer itself as a dense, non-aqueous phase liquid, or DNAPL. The objective of the field test was to assess the efficacy of the surfactant for in situ TCE solubilization. Although the test demonstrated that sorbitan monooleate was unsuitable as a solubilizer in this aquifer, the single-well test was demonstrated to be a viable method for the in situ testing of surfactants or cosolvents prior to proceeding to full-scale remediation.

  17. Factors Influencing the Mobility of Microorganisms in a Small-Scale Injection and Recovery Test Performed in a Sandy Aquifer

    NASA Astrophysics Data System (ADS)

    Metge, D. W.; Harvey, R. W.; Rogers, J. R.

    2001-12-01

    The effect of motility and physical characteristics upon the relative transport behaviors of three bacterial strains (groundwater isolates) and a virus (H40, a 150 nm marine bacteriophage) were assessed in July 2001 in a small-scale, natural-gradient injection and recovery study involving an array of multilevel samplers (MLS) installed in a sandy aquifer in Cape Cod, MA. The bacteria included a motile Pseudomonas sp. (1.5-2.2 μ m long, 1.07 g/cm3), a non-motile mutant of the same species; and a Staphylococcus sp. (0.5-0.8 μ m diameter, 1.08 g/cm3). The virus, three bacteria strains, and conservative tracer (bromide) were introduced to the aquifer as a 107-L pulse injection into two conductive layers that differed in terms of groundwater velocity. For the faster layer, peak breakthroughs for all three bacterial strains at 1 m downgradient from the point of injection were coincident with that of the bromide tracer, although the magnitudes of breakthrough varied up to 10-fold. In contrast, the tailed bacteriophage (H40) was retarded by a factor of ~3. For the slower layer, the motile Pseudomonas sp. exhibited substantial longitudinal spreading and two distinct breakthrough peaks. The first peak arrived before that of bromide. However, the second peak was retarded by a factor of 2. Peak concentrations of its non-motile mutant and the Staphylococcus sp. arrived coincidently with that of bromide. As was the case for the faster layer, breakthrough of the virus in the slower layer was significantly retarded. The data suggest that a microorganism's motility and physical characteristics can substantively affect its transport behavior in aquifer sediments, although the relative degrees of influence for these factors may be modified by aquifer heterogeneities.

  18. Two-dimensional flow-through microcosms - Versatile test systems to study biodegradation processes in porous aquifers

    NASA Astrophysics Data System (ADS)

    Bauer, Robert D.; Rolle, Massimo; Kürzinger, Petra; Grathwohl, Peter; Meckenstock, Rainer U.; Griebler, Christian

    2009-05-01

    SummaryA fundamental prerequisite of any remedial activity is a sound knowledge of both the biotic and abiotic processes involved in transport and degradation of contaminants. Investigations of these aspects in situ often seem infeasible due to the complexity of interacting processes. A simplified portrayal of nature can be facilitated in laboratory-based two-dimensional (2D) sediment flow-through microcosms. This paper describes the versatility of such simple aquifer model systems with respect to biodegradation of aromatic hydrocarbons, i.e. toluene and ethylbenzene, under various environmental conditions. Initially constructed to study non-reactive and bioreactive transport of organic contaminants in homogeneous porous media under steady state hydraulic conditions, experimental setups developed towards more realistic heterogeneous sediment packing and transient hydraulic conditions. High-resolution spatial and temporal sampling allowed to obtain new insights on the distribution of bioactivities in contaminant plumes and associated controlling and limiting factors. Major biodegradation activities in saturated porous sediments are located at the fringes of contaminant plumes and are driven by dispersive mixing. These hot-spots of contaminant biotransformation are characterized by steep physical-chemical gradients in the millimeter to centimeter range. Sediment heterogeneity, i.e. high-conductivity zones, was shown to significantly enhance transverse mixing and subsequently biodegradation. On the contrary, transient hydraulic conditions may generate intermediate disturbances to biodegrader populations and thus may interfere with optimized contaminant conversion. However, a bacterial strain aerobically degrading toluene, i.e. Pseudomonas putida F1, was shown to adapt to vertically moving contaminant plumes, in the way that it regained full biodegradation potential two-times faster in areas with a mid-term (days to weeks) contamination history than in areas not

  19. Modeling a Combined Tracer and Time-Lapse Radar Imaging Test in the Heterogeneous Fluvial Aquifer at the Boise Hydrogeophysical Research Site

    NASA Astrophysics Data System (ADS)

    Leven, C.; Barrash, W.; Hyndman, D. W.; Johnson, T. C.

    2002-12-01

    magnitude across the measured vertical dimension. We will present results from transient three-dimensional flow and transport models of the time-lapse tracer test, implemented using information from the dynamic cross-well radar tomography measurements. Preliminary modeling shows that the transport of the solute plume is strongly influenced by both small-scale aquifer heterogeneity and the geometry of hydrostratigraphic units. The dynamic plume imaging approach that we are developing should lead to a comprehensive description, characterization, and quantification of aquifer heterogeneity of the BHRS.

  20. In Situ Reduction of Aquifer Sediments to Create a Permeable Reactive Barrier to Remediate Chromate (CrO4 2-): BenchScale Tests to Determine Barrier Longevity

    SciTech Connect

    Szecsody, Jim E.; Fruchter, Jonathan S.; Vermeul, Vince R.; Williams, Mark D.; Devary, Brooks J.

    2005-01-02

    Laboratory tests were conducted to determine sediment geochemical properties needed to develop a design for implementation of the in-situ oxidation–reduction (redox) manipulation (ISRM) technology for chromate (CrO42–) remediation at a Superfund site and three other sites. A generalized hydrogeologic description of the Superfund site consist of a silty clay upper confining layer to a depth of ~6.71 m, the A1 unit from ~6.71 m to ~8.23 m, the A2 unit from ~8.23 m to ~10.67 m, and the A3 unit from ~10.67 m to ~12.19 m below ground surface. The A/B aquitard was encountered at a depth of ~12.19 m. The A1, A2, and A3 hydrostratigraphic units are all sandy gravels, but with considerable difference in fines content and subsequently, hydraulic conductivity. Hydraulic tests conducted in pilot test site monitoring wells indicate that the A1 unit has a 10 times lower hydraulic conductivity than the A2 unit, while the A3 unit hydraulic conductivity is significantly higher than that observed in the A2 unit (i.e., a trend of increasing permeability with depth). Calculated hydraulic conductivities, based on sieve analysis, show this same spatial trend. Results from a tracer injection test and electromagnetic borehole flow meter tests conducted at the site indicate a relatively high degree of formation heterogeneity. Laboratory experiments showed that chemical reduction yielded a redox capacity (0.26% iron(II)) that falls within the range of values observed in sediments analyzed from sites where field-scale deployment of the ISRM technology is currently in progress or being considered (0.1% Hanford 100D area, 0.24% Ft Lewis, 0.4% Moffett Federal Airfield). There was relatively little spatial variability in reducible iron (Fe) content between the three aquifer units. This mass of reducible Fe represents a sufficient quantity for a treatment zone emplaced to remain anoxic for 430 pore volumes, which would be expected to last tens of years, depending on aquifer flow rates and the

  1. Aquifer-test evaluation and potential effects of increased ground-water pumpage at the Stovepipe Wells Hotel area, Death Valley National Monument, California

    USGS Publications Warehouse

    Woolfenden, L.R.; Martin, Peter; Baharie, Brian

    1988-01-01

    Ground-water use in the Stovepipe Wells Hotel area in Death Valley National Monument is expected to increase significantly if the nonpotable, as well as potable, water supply is treated by reverse osmosis. During the peak tourist season, October through March, ground-water pumpage could increase by 37,500 gallons per day, or 76%. The effects of this additional pumpage on water levels in the area, particularly near a strand of phreatophytes about 10,000 feet east of the well field, are of concern. In order to evaluate the effects of increased pumpage on water levels in the Stovepipe Wells Hotel area well field, two aquifer tests were performed at the well field to determine the transmissivity and storage coefficients of the aquifer. Analysis of the aquifer test determined that a transmissivity of 1,360 feet squared per day was representative of the aquifer. The estimated value of transmissivity and the storage-coefficient values that are representative of confined (1.2 x .0004) and unconfined (0.25) conditions were used in the Theis equation to calculate the additional drawdown that might occur after 1, 10, and 50 years of increased pumpage. The drawdown calculated by using the lower storage-coefficient value represents the maximum additional drawdown that might be expected from the assumed increase in pumpage; the drawdown calculated by using the higher storage-coefficient value represents the minimum additional drawdown. Calculated additional drawdowns after 50 years of pumping range from 7.8 feet near the pumped well to 2.4 feet at the phreatophyte stand assuming confined conditions, and from 5.7 feet near the pumped well to 0.3 foot at the phreatophyte stand assuming unconfined conditions. Actual drawdowns probably will be somewhere between these values. Drawdowns measured in observation wells during 1973-85, in response to an average pumpage of 34,200 gallons per day at the Stovepipe Wells Hotel well field, are similar to the drawdowns calculated by the Theis

  2. Subsurface Residence Times as an Algorithm for Aquifer Sensitivity Mapping: testing the concept with analytic element ground water models in the Contentnea Creek Basin, North Carolina, USA

    NASA Astrophysics Data System (ADS)

    Kraemer, S. R.

    2002-05-01

    The objective of this research is to test the utility of simple functions of spatially integrated and temporally averaged ground water residence times in shallow groundwatersheds with field observations and detailed computer simulations. The residence time of water in the subsurface is arguably a surrogate of aquifer sensitivity to contamination --- short contact time in subsurface media may result in reduced contaminant assimilation prior to discharge to a well or stream. Residence time is an established criterion for the delineation of wellhead protection areas. The residence time of water may also have application in assessing the connection between landscape and fair weather loadings of non-point source pollution to streams, such as the drainage of nitrogen-nitrate from agricultural fields as base flow. The field setting of this study includes a hierarchy of catchments in the Contentnea Creek basin (2600 km2) of North Carolina, USA, centered on the intensive coastal plain field study site at Lizzie, NC (1.2+km^2), run by the US Geological Survey and the NC Department of Environment and Natural Resources of Raleigh, NC. Analytic element models are used to define the advective flow field and regional boundary conditions. The issues of conceptual model complexity are explored using the multi-layer object oriented analytic element model Tim, and by embedding the finite difference model MODFLOW within the analytic element model GFLOW copyright. The models are compared to observations of hydraulic head, base flow separations, and aquifer geochemistry and age dating evidence. The resulting insights are captured and mapped across the basin as zones of average aquifer residence time using ArcView copyright GIS tools. Preliminary results and conclusions will be presented. Mention of commercial software does not constitute endorsement or recommendation for use.

  3. BAT3 Analyzer: Real-Time Data Display and Interpretation Software for the Multifunction Bedrock-Aquifer Transportable Testing Tool (BAT3)

    USGS Publications Warehouse

    Winston, Richard B.; Shapiro, Allen M.

    2007-01-01

    The BAT3 Analyzer provides real-time display and interpretation of fluid pressure responses and flow rates measured during geochemical sampling, hydraulic testing, or tracer testing conducted with the Multifunction Bedrock-Aquifer Transportable Testing Tool (BAT3) (Shapiro, 2007). Real-time display of the data collected with the Multifunction BAT3 allows the user to ensure that the downhole apparatus is operating properly, and that test procedures can be modified to correct for unanticipated hydraulic responses during testing. The BAT3 Analyzer can apply calibrations to the pressure transducer and flow meter data to display physically meaningful values. Plots of the time-varying data can be formatted for a specified time interval, and either saved to files, or printed. Libraries of calibrations for the pressure transducers and flow meters can be created, updated and reloaded to facilitate the rapid set up of the software to display data collected during testing with the Multifunction BAT3. The BAT3 Analyzer also has the functionality to estimate calibrations for pressure transducers and flow meters using data collected with the Multifunction BAT3 in conjunction with corroborating check measurements. During testing with the Multifunction BAT3, and also after testing has been completed, hydraulic properties of the test interval can be estimated by comparing fluid pressure responses with model results; a variety of hydrogeologic conceptual models of the formation are available for interpreting fluid-withdrawal, fluid-injection, and slug tests.

  4. Factors Affecting Specific-Capacity Tests and their Application--A Study of Six Low-Yielding Wells in Fractured-Bedrock Aquifers in Pennsylvania

    USGS Publications Warehouse

    Risser, Dennis W.

    2010-01-01

    This report by the U.S. Geological Survey, prepared in cooperation with the Pennsylvania Department of Environmental Protection, Bureau of Mining and Reclamation, evaluates factors affecting the application of specific-capacity tests in six low-yielding water wells in areas of coal mining or quarrying in Pennsylvania. Factors such as pumping rate, duration of pumping, aquifer properties, wellbore storage, and turbulent flow were assessed by theoretical analysis and by completing multiple well tests, selected to be representative of low-yielding household-supply wells in areas of active coal mining or quarrying. All six wells were completed in fractured-bedrock aquifers--five in coal-bearing shale, siltstone, sandstone, limestone, and coal of Pennsylvanian and Permian age and one in limestone of Cambrian age. The wells were pumped 24 times during 2007-09 at rates from 0.57 to 14 gallons per minute during tests lasting from 22 to 240 minutes. Geophysical logging and video surveys also were completed to determine the depth, casing length, and location of water-yielding zones in each of the test wells, and seasonal water-level changes were measured during 2007-09 by continuous monitoring at each well. The tests indicated that specific-capacity values were reproducible within about ? 20 percent if the tests were completed at the same pumping rate and duration. A change in pumping duration, pumping rate, or saturated aquifer thickness can have a substantial effect on the comparability of repeated tests. The largest effect was caused by a change in aquifer thickness in well YO 1222 causing specific capacity from repeated tests to vary by a factor of about 50. An increase in the duration of pumping from 60 to 180 minutes caused as much as a 62 percent decrease in specific capacity. The effect of differing pumping rates on specific capacity depends on whether or not the larger rate causes the water level in the well to fall below a major water-yielding zone; when this

  5. Testing the 14C ages and conservative behavior of dissolved 14C in a carbonate aquifer in Yucca Flat, Nevada (USA), using 36Cl from groundwater and packrat middens

    NASA Astrophysics Data System (ADS)

    Kwicklis, Edward; Farnham, Irene

    2014-09-01

    Corrected groundwater 14C ages from the carbonate aquifer in Yucca Flat at the former Nevada Test Site (now the Nevada National Security Site), USA, were evaluated by comparing temporal variations of groundwater 36Cl/Cl estimated with these 14C ages with published records of meteoric 36Cl/Cl variations preserved in packrat middens (piles of plant fragments, fecal matter and urine). Good agreement between these records indicates that the groundwater 14C ages are reasonable and that 14C is moving with chloride without sorbing to the carbonate rock matrix or fracture coatings, despite opposing evidence from laboratory experiments. The groundwater 14C ages are consistent with other hydrologic evidence that indicates significant basin infiltration ceased 8,000 to 10,000 years ago, and that recharge to the carbonate aquifer is from paleowater draining through overlying tuff confining units along major faults. This interpretation is supported by the relative age differences as well as hydraulic head differences between the alluvial and volcanic aquifers and the carbonate aquifer. The carbonate aquifer 14C ages suggest that groundwater velocities throughout much of Yucca Flat are about 2 m/yr, consistent with the long-held conceptual model that blocking ridges of low-permeability rock hydrologically isolate the carbonate aquifer in Yucca Flat from the outlying regional carbonate flow system.

  6. Digital modeling of radioactive and chemical waste transport in the aquifer underlying the Snake River Plain at the National Reactor Testing Station, Idaho

    USGS Publications Warehouse

    Robertson, J.B.

    1974-01-01

    Industrial and low-level radioactive liquid wastes at the National Reactor Testing Station (NRTS) in Idaho have been disposed to the Snake River Plain aquifer since 1952. Monitoring studies have indicated that tritium and chloride have dispersed over a 15-square mile (39-square kilometer) area of the aquifer in low but detectable concentrations and have only migrated as far as 5 miles (8 kilometers) downgradient from discharge points. The movement of cationic waste solutes, particularly 90Sr and 137Cs, has been significantly retarded due to sorption phenomena, principally ion exchange. 137Cs has shown no detectable migration in the aquifer and 90Sr has migrated only about 1.5 miles (2 kilometers) from the Idaho Chemical Processing Plant (ICPP) discharge well, and is detectable over an area of only 1.5 square miles ( 4 square kilometers) of the aquifer. Digital modeling techniques have been applied successfully to the analysis of the complex waste-transport system by utilizing numerical solution of the coupled equations of groundwater motion and mass transport. The model includes the effects of convective transport, flow divergence, two-dimensional hydraulic dispersion, radioactive decay, and reversible linear sorption. The hydraulic phase of the model uses the iterative, alternating direction, implicit finite-difference scheme to solve the groundwater flow equations, while the waste-transport phase uses a modified method of characteristics to solve the solute transport equations simulated by the model. The modeling results indicate that hydraulic dispersion (especially transverse) is a much more significant influence than previously suggested by earlier studies. The model has been used to estimate future waste migration patterns for varied assumed hydrological and waste conditions up through the year 2000. The hydraulic effects of recharge from the Big Lost River have an important (but not predominant) influence on the simulated future migration patterns. For the

  7. Geochemical Trends and Natural Attenuation of RDX, Nitrate, and Perchlorate in the Hazardous Test Area Fractured-Granite Aquifer, White Sands Missile Range, New Mexico, 1996-2006

    USGS Publications Warehouse

    Langman, Jeff B.; Robertson, Andrew J.; Bynum, Jamar; Gebhardt, Fredrick E.

    2008-01-01

    A fractured-granite aquifer at White Sands Missile Range is contaminated with the explosive compound RDX, nitrate, and perchlorate (oxidizer associated with rocket propellant) from the previous use of the Open Burn/Open Detonation site at the Hazardous Test Area. RDX, nitrate, and perchlorate ground-water concentrations were analyzed to examine source characteristics, spatial and temporal variability, and the influence of the natural attenuation processes of dilution and degradation in the Hazardous Test Area fractured-granite aquifer. Two transects of ground-water wells from the existing monitoring-site network - one perpendicular to ground-water flow (transect A-A') and another parallel to ground-water flow (transect B-B') - were selected to examine source characteristics and the spatial and temporal variability of the contaminant concentrations. Ground-water samples collected in 2005 from a larger sampling of monitoring sites than the two transects were analyzed for various tracers including major ions, trace elements, RDX degradates, dissolved gases, water isotopes, nitrate isotopes, and sulfate isotopes to examine the natural attenuation processes of dilution and degradation. Recharge entrains contaminants at the site and transports them downgradient towards the Tularosa Basin floor through a poorly connected fracture system(s). From 1996 to 2006, RDX, nitrate, and perchlorate concentrations in ground water downgradient from the Open Burn/Open Detonation site have been relatively stable. RDX, nitrate, and perchlorate in ground water from wells near the site indicate dispersed contaminant sources in and near the Open Burn/Open Detonation pits. The sources of RDX and nitrate in the pit area have shifted with time, and the shift correlates with the regrading of the south and east berms of each pit in 2002 and 2003 following closure of the site. The largest RDX concentrations were in ground water about 0.1 mile downgradient from the pits, the largest perchlorate

  8. Borehole geophysical logging and aquifer-isolation tests conducted in well MG-1693 at North Penn Area 5 Superfund Site near Colmar, Montgomery County, Pennsylvania

    USGS Publications Warehouse

    Bird, Philip H.

    2006-01-01

    Borehole geophysical logging and aquifer-isolation (packer) tests were conducted in well MG-1693 (NP-87) at the North Penn Area 5 Superfund Site near Colmar, Montgomery County, Pa. Objectives of the study were to identify the depth and yield of water-bearing zones, occurrence of vertical borehole flow, and effects of pumping on water levels in nearby wells. Caliper, natural-gamma, single-point-resistance, fluid-temperature, fluid-resistivity, heatpulse-flowmeter, and borehole-video logs were collected. Vertical borehole-fluid movement direction and rate were measured under nonpumping conditions. The suite of logs was used to locate water-bearing fractures, determine zones of vertical borehole-fluid movement, and select depths to set packers. Aquifer-isolation tests were conducted to sample discrete intervals and to determine specific capacities of water-bearing zones and effects of pumping individual zones on water levels in two nearby monitor wells. Specific capacities of isolated zones during aquifer-isolation tests ranged from 0.03 to 3.09 (gal/min)/ft (gallons per minute per foot). Fractures identified by borehole geophysical methods as water-producing or water-receiving zones produced water when isolated and pumped. Water enters the borehole primarily through high-angle fractures at 416 to 435 ft bls (feet below land surface) and 129 to 136 ft bls. Water exits the borehole through a high-angle fracture at 104 to 107 ft bls, a broken casing joint at 82 ft bls, and sometimes as artesian flow through the top of the well. Thirteen intervals were selected for aquifer-isolation testing, using a straddle-packer assembly. The specific capacity of interval 1 was 2.09 (gal/min)/ft. The specific capacities of intervals 2, 3, and 4 were similar: 0.27, 0.30, and 0.29 (gal/min)/ft,respectively. The specific capacities of intervals 5, 6, 7, 8, and 10 were similar: 0.03, 0.04, 0.09, 0.09, and 0.04 (gal/min)/ft,respectively. Intervals 9, 11, and 12 each showed a strong

  9. Aquifer-test data for wells H-1, H-2A, H-2B, H-2C, and H-3 at the Waste Isolation Pilot Plant, southeastern New Mexico

    USGS Publications Warehouse

    Huff, G.F.; Gregory, Angela

    2006-01-01

    A series of aquifer tests was performed by the U.S. Geological Survey on geologic units of Permian age at the Waste Isolation Pilot Plant site between February 1979 and July 1980 in wells H-1, H-2 complex (H-2A, H-2B, and H-2C), and H-3. The tested geologic units included the Magenta Dolomite and Culebra Dolomite Members of the Rustler Formation, and the contact zone between the Rustler and Salado Formations. Selected information on the tested formations, test dates, pre-test static water levels, test configurations, and raw data collected during these tests are tabulated in this report.

  10. Testing the sensitivity of pumpage to increases in surficial aquifer system heads in the Cypress Creek well-field area, West-Central Florida : an optimization technique

    USGS Publications Warehouse

    Yobbi, Dann K.

    2002-01-01

    Tampa Bay depends on ground water for most of the water supply. Numerous wetlands and lakes in Pasco County have been impacted by the high demand for ground water. Central Pasco County, particularly the area within the Cypress Creek well field, has been greatly affected. Probable causes for the decline in surface-water levels are well-field pumpage and a decade-long drought. Efforts are underway to increase surface-water levels by developing alternative sources of water supply, thus reducing the quantity of well-field pumpage. Numerical ground-water flow simulations coupled with an optimization routine were used in a series of simulations to test the sensitivity of optimal pumpage to desired increases in surficial aquifer system heads in the Cypress Creek well field. The ground-water system was simulated using the central northern Tampa Bay ground-water flow model. Pumping solutions for 1987 equilibrium conditions and for a transient 6-month timeframe were determined for five test cases, each reflecting a range of desired target recovery heads at different head control sites in the surficial aquifer system. Results are presented in the form of curves relating average head recovery to total optimal pumpage. Pumping solutions are sensitive to the location of head control sites formulated in the optimization problem and as expected, total optimal pumpage decreased when desired target head increased. The distribution of optimal pumpage for individual production wells also was significantly affected by the location of head control sites. A pumping advantage was gained for test-case formulations where hydraulic heads were maximized in cells near the production wells, in cells within the steady-state pumping center cone of depression, and in cells within the area of the well field where confining-unit leakance is the highest. More water was pumped and the ratio of head recovery per unit decrease in optimal pumpage was more than double for test cases where hydraulic heads

  11. Results of the reactant sand-fracking pilot test and implications for the in situ remediation of chlorinated VOCs and metals in deep and fractured bedrock aquifers.

    PubMed

    Marcus, D L; Bonds, C

    1999-08-12

    Permeable reactive barriers (PRBs), such as the Waterloo Funnel and Gate System, first implemented at Canadian Forces Borden facility in 1992, are a passive remediation technology capable of controlling the migration of, and treating contaminated groundwater in situ. Most of the PRBs installed to date have been shallow installations created by backfilling sheet-pile shored excavations with iron filing reactive media. More recently continuous trenchers [R. Puls, Installation of permeable reactive barriers using continuous trenching equipment, Proceedings of the RTDF Permeable Barriers Work Group, Virginia Beach, VA, September 1997] and Caissons [J. Vogan, Caisson installation of a pilot scale, permeable reactive barrier in situ treatment zone at the Sommersworth Landfill, NH, Presented to the RTDF Permeable Barriers Work Group, Alexandria, VA, April 1996], and vertical fracturing emplacements [G. Hocking, Vertical hydraulic fracture emplacement of permeable reactive barriers, Progress Report delivered to the Permeable Reactive Barriers Workgroup of the Remedial Technology Development Forum, Beaverton, OR, April 1998] have been used to create reactive barriers in soil. None of the prior methods are capable of adequately addressing groundwater contamination in deep and fractured bedrock aquifers. The purpose of the RSF pilot study was to install reactive media into an impacted bedrock aquifer, and to evaluate the effectiveness of in situ treatment of chlorinated volatile organic compounds (CVOCs) and metals in that type of aquifer. Three discrete fractures were identified and treated and were subjected to testing before and after treatment. Between 300 and 1700 lb. of 1 mm diameter reactive proppants were injected into each zone to facilitate treatment. Monitoring data obtained from adjacent observation wells verified that fracking fluids reached at least 42 ft from the treatment well following hydrofracturing. The concentrations of many of the CVOCs decreased up to

  12. Results of the reactant sand-fracking pilot test and implications for the in situ remediation of chlorinated VOCs and metals in deep and fractured bedrock aquifers.

    PubMed

    Marcus, D L; Bonds, C

    1999-08-12

    Permeable reactive barriers (PRBs), such as the Waterloo Funnel and Gate System, first implemented at Canadian Forces Borden facility in 1992, are a passive remediation technology capable of controlling the migration of, and treating contaminated groundwater in situ. Most of the PRBs installed to date have been shallow installations created by backfilling sheet-pile shored excavations with iron filing reactive media. More recently continuous trenchers [R. Puls, Installation of permeable reactive barriers using continuous trenching equipment, Proceedings of the RTDF Permeable Barriers Work Group, Virginia Beach, VA, September 1997] and Caissons [J. Vogan, Caisson installation of a pilot scale, permeable reactive barrier in situ treatment zone at the Sommersworth Landfill, NH, Presented to the RTDF Permeable Barriers Work Group, Alexandria, VA, April 1996], and vertical fracturing emplacements [G. Hocking, Vertical hydraulic fracture emplacement of permeable reactive barriers, Progress Report delivered to the Permeable Reactive Barriers Workgroup of the Remedial Technology Development Forum, Beaverton, OR, April 1998] have been used to create reactive barriers in soil. None of the prior methods are capable of adequately addressing groundwater contamination in deep and fractured bedrock aquifers. The purpose of the RSF pilot study was to install reactive media into an impacted bedrock aquifer, and to evaluate the effectiveness of in situ treatment of chlorinated volatile organic compounds (CVOCs) and metals in that type of aquifer. Three discrete fractures were identified and treated and were subjected to testing before and after treatment. Between 300 and 1700 lb. of 1 mm diameter reactive proppants were injected into each zone to facilitate treatment. Monitoring data obtained from adjacent observation wells verified that fracking fluids reached at least 42 ft from the treatment well following hydrofracturing. The concentrations of many of the CVOCs decreased up to

  13. Aquifer-test results, direction of ground-water flow, and 1984-90 annual ground-water pumpage for irrigation, lower Big Lost River Valley, Idaho

    USGS Publications Warehouse

    Bassick, M.D.; Jones, M.L.

    1992-01-01

    ,600 acre-ft; average annual flow of the Big Lost River near Arco (gaging station 13132500; see map showing water-level contours) in water years 1947-61, 1967-80, and 1983-90 was about 79,000 acre-ft (Harenberg and others, 1991, p. 254-255). Moore Canal and East Side Ditch divert water from the Big Lost River at the Moore Diversion, 3 mi north of Moore (see map showing water-level contours) and supply water for irrigation near the margins of the valley. When water supply is average or greater, water in the Big Lost River flows through the study area and onto the Snake River Plain, where it evaporates or infiltrates into the Snake River Plain aquifer. When water supply is below average, water in the Big Lost River commonly does not reach Arco; rather, it is diverted for irrigation in the interior of the valley, evaporates, or infiltrates to the valley-fill aquifer. This report describes the results of a study by the U.S. Geological Survey, in cooperation with the Idaho Department of Water Resources, to collect hydrologic data needed to help address water-supply problems in the Big Lost River Valley. Work involved (1) field inventory of 81 wells, including 46 irrigation wells; (2) measurement of water levels in 154 wells in March 1991; (3) estimation of annual ground-water pumpage for irrigation from 1984 through 1990; and (4) analysis of results of an aquifer test conducted southwest of Moore. All data obtained during this study may be inspected at the U.S. Geological Survey, Idaho District office, Boise.

  14. I-131 rose bengal excretion test is not dead

    SciTech Connect

    Antico, V.F.; Denhartog, P.; Ash, J.M.; Gilday, D.L.; Houle, S.

    1985-03-01

    One hundred and thirty I-131 Rose Bengal Excretion Studies (RBI) were performed on 84 patients over nine years. In 90% (56/60) of cases with biliary atresia, the 72-hour RBI was less than or equal to 7%. In only 12.5% (3/24) of cases with neonatal hepatitis was the 72-hour RBI less than or equal to 7%. The accuracy of the test was 91% with a specificity of 88%. Thirty patients later were studied following a Kasai procedure. The RBI test reliably predicted the patency of the anastomosis. The authors conclude that the 72-hour RBI is a reliable test in the diagnosis of biliary atresia and in the documentation of biliary patency following surgery, provided adequate care is taken in stool collection and measurement.

  15. Cyclic injection, storage, and withdrawal of heated water in a sandstone aquifer at St. Paul, Minnesota--Analysis of thermal data and nonisothermal modeling of short-term test cycles

    USGS Publications Warehouse

    Miller, Robert T.; Delin, G.N.

    2002-01-01

    In May 1980, the University of Minnesota began a project to evaluate the feasibility of storing heated water (150 degrees Celsius) in the Franconia-Ironton Galesville aquifer (183 to 245 meters below land surface) and later recovering it for space heating. The University's steam-generation facilities supplied high-temperature water for injection. The Aquifer Thermal-Energy Storage system is a doublet-well design in which the injection-withdrawal wells are spaced approximately 250 meters apart. Water was pumped from one of the wells through a heat exchanger, where heat was added or removed. This water was then injected back into the aquifer through the other well. Four short-term test cycles were completed. Each cycle consisted of approximately equal durations of injection and withdrawal ranging from 5.25 to 8.01 days. Equal rates of injection and withdrawal, ranging from 17.4 to 18.6 liters per second, were maintained for each short-term test cycle. Average injection temperatures ranged from 88.5 to 117.9 degrees Celsius. Temperature graphs for selected depths at individual observation wells indicate that the Ironton and Galesville Sandstones received and stored more thermal energy than the upper part of the Franconia Formation. Clogging of the Ironton Sandstone was possibly due to precipitation of calcium carbonate or movement of fine-grain material or both. Vertical-profile plots indicate that the effects of buoyancy flow were small within the aquifer. A three-dimensional, anisotropic, nonisothermal, ground-water-flow, and thermal-energy-transport model was constructed to simulate the four short-term test cycles. The model was used to simulate the entire short-term testing period of approximately 400 days. The only model properties varied during model calibration were longitudinal and transverse thermal dispersivities, which, for final calibration, were simulated as 3.3 and 0.33 meters, respectively. The model was calibrated by comparing model-computed results to

  16. Optimizing remediation monitoring by evaluating depth-specific water velocity in a polluted aquifer: The borehole dilution test applied to multilevel samplers, a case study at the AGTROL industrial site, Bordeaux (France)

    NASA Astrophysics Data System (ADS)

    Bourg, A. C.; Kedziorek, M. A.; Dupuy, A.

    2009-12-01

    For contaminant plumes in hydraulically stratified aquifers, identifying depths of preferential groundwater flow is essential because this is where the actual transport takes place and therefore might be where dedicated monitoring should be done. We present here a method (adapted from the single borehole dilution tracer test) in which a volume of tracer solution is injected into a port of a multi-level sampler at a given depth and small volumes of water are retrieved through the same port at specific times. The correlation between tracer concentration and time is used to calculate the renewal time of a volume of water in the aquifer and estimate pore velocity (or specific discharge). The method is tested on a fill phreatic aquifer in Southwestern France, polluted by sulfuric acid and copper (pH as low as 1 and dissolved sulfate and copper as high as 45 and 30 g/L, respectively, near the source of the contaminant plume). Core sample analyses indicate that copper is trapped on the edge of the plume as a solid at specific depths that correspond to carbonate depletion (water pH increasing due to pH buffer). Groundwater flows more rapidly at these depths. As a result, these aquifer layers are not only permeable and water transmittive but also geochemically reactive. Natural attenuation should therefore be monitored at these depths.

  17. Aquifer-test data and borehole flow test results from monitoring well 16P52 at the South Trend development area number 1, McKinley County, New Mexico

    USGS Publications Warehouse

    Stevens, Ken

    1984-01-01

    Mobil Oil Corporation personnel have designated at least four sandstone intervals, A-D (top to bottom), on the single-point resistivity logs of wells drilled in the South Trend Development Area. This report presents time-drawdown data reported by Mobil Oil Corporation from singly (A or B or C or D sandstone interval) and multiply (A, B, C, and D sandstone Intervals) completed wells for the August 16-17, 1982 aquifer test at the South Trend Development Area Site 1. This report also describes the results of flowmeter and brine-injection tests by the U.S. Geological Survey in monitoring well 16P52. Well 16P52 is open to sandstone intervals A, B, C, and D. On July 26, 1982, water was injected at a rate of 1.43 cubic feet per minute above the A sandstone interval in well 16P52. Based on flowmeter data, the calculated rates of flow were 1.23 cubic feet per minute between the A and B sandstone intervals, 0.63 cubic foot per minute between the B and C sandstone intervals, and less than 0.17 cubic foot per minute between the C and D sandstone intervals. Based upon brine-slug-injection tests conducted during August 1982, the calculated flow rates between sandstone intervals A and B are as follows: 0.01 cubic foot per minute upward flow (B to A) about 5 hours after pumping began for the aquifer test; 0.004 cubic foot per minute upward flow (B to A) about 21 hours after pumping began; and 0.0 cubic foot per minute about 46 hours after the pump was turned off. All other brine-slug-injection tests measured no flow.

  18. High Temperature Aquifer Storage

    NASA Astrophysics Data System (ADS)

    Ueckert, Martina; Niessner, Reinhard; Baumann, Thomas

    2015-04-01

    Combined heat and power generation (CHP) is highly efficient because excess heat is used for heating and/or process energy. However, the demand of heat energy varies considerably throughout the year while the demand for electrical energy is rather constant. It seems economically and ecologically highly beneficial for municipalities and large power consumers such as manufacturing plants to store excess heat in groundwater aquifers and to recuperate this energy at times of higher demand. Apart from the hydrogeological conditions, high transmissivity and favorable pressure gradients, the hydrochemical conditions are crucial for long-term operation. Within the project High Temperature Aquifer Storage, scientists investigate storage and recuperation of excess heat energy into the bavarian Malm aquifer. After one year of planning, construction, and the successful drilling of a research well to 495 m b.s.l. the first large scale heat storage test in the Malm aquifer was finished just before Christmas 2014. An enormous technical challenge was the disruption of the carbonate equilibrium - modeling results indicated a carbonate precipitation of 10-50 kg/d in the heat exchangers. The test included five injection pulses of hot water (60 °C up to 110 °C) and four tracer pulses, each consisting of a reactive and a conservative fluorescent dye. Injection and production rates were 15 L/s. About 4 TJ of heat energy were necessary to achieve the desired water temperatures. Electrical conductivity, pH and temperature were recorded at a bypass where also samples were taken. A laboratory container at the drilling site was equipped for the analysis of the concentration of the tracers and the cation concentrations at sampling intervals of down to 15 minutes. Additional water samples were taken and analyzed for major ions and trace elements in the laboratory. The disassembled heat exchanger proved that precipitation was successfully prevented by adding CO2 to the water before heating

  19. High Temperature Aquifer Storage

    NASA Astrophysics Data System (ADS)

    Ueckert, Martina; Niessner, Reinhard; Baumann, Thomas

    2016-04-01

    Combined heat and power generation (CHP) is highly efficient because excess heat is used for heating and/or process energy. However, the demand of heat energy varies considerably throughout the year while the demand for electrical energy is rather constant. It seems economically and ecologically highly beneficial for municipalities and large power consumers such as manufacturing plants to store excess heat in groundwater aquifers and to recuperate this energy at times of higher demand. Within the project High Temperature Aquifer Storage, scientists investigate storage and recuperation of excess heat energy into the bavarian Malm aquifer. Apart from high transmissivity and favorable pressure gradients, the hydrochemical conditions are crucial for long-term operation. An enormous technical challenge is the disruption of the carbonate equilibrium - modeling results indicated a carbonate precipitation of 10 - 50 kg/d in the heat exchangers. The test included five injection pulses of hot water (60 °C up to 110 °C) and four tracer pulses, each consisting of a reactive and a conservative fluorescent dye, into a depth of about 300 m b.s.l. resp. 470 m b.s.l. Injection and production rates were 15 L/s. To achieve the desired water temperatures, about 4 TJ of heat energy were necessary. Electrical conductivity, pH and temperature were recorded at a bypass where also samples were taken. A laboratory container at the drilling site was equipped for analysing the concentration of the dyes and the major cations at sampling intervals of down to 15 minutes. Additional water samples were taken and analysed in the laboratory. The disassembled heat exchanger prooved that precipitation was successfully prevented by adding CO2 to the water before heating. Nevertheless, hydrochemical data proved both, dissolution and precipitation processes in the aquifer. This was also suggested by the hydrochemical modelling with PhreeqC and is traced back to mixture dissolution and changing

  20. Interpretation of geophysical logs, aquifer tests, and water levels in wells in and near the North Penn Area 7 Superfund site, Upper Gwynedd Township, Montgomery County, Pennsylvania, 2000-02

    USGS Publications Warehouse

    Senior, Lisa A.; Cinotto, Peter J.; Conger, Randall W.; Bird, Philip H.; Pracht, Karl A.

    2005-01-01

    Ground water in the vicinity of various industrial facilities in Upper Gwynedd Township and Lansdale Borough, Montgomery County, Pa., is contaminated with various volatile organic compounds (VOCs). 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, water-level monitoring, and streamflow measurements in the vicinity of North Penn Area 7 beginning autumn 2000 to assist the USEPA in developing an understanding of the hydrogeologic framework in the area as part of the USEPA Remedial Investigation. The study area is underlain by Triassic and Jurassic-age sandstones, siltstones, and shales of the Lockatong Formation and the Brunswick Group. 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 layered aquifers of differing permeabilities. The aquifers are recharged by precipitation and discharge to streams and wells. The Wissahickon Creek headwaters are less than 1 mile northeast of the study area, and this stream flows southwest to bisect North Penn Area 7. Ground water is pumped in the vicinity of North Penn Area 7 for industrial use and public supply. The USGS collected geophysical logs for 16 wells that ranged in depth from 50 to 623 feet. Aquifer-interval-isolation testing was done in 9 of the 16 wells, for a total of 30 zones tested. A multiple-well aquifer test was conducted by monitoring the response of 14 wells to pumping a 600-ft deep production well in February and March 2002. In addition, water levels were monitored continuously in three wells in the area and streamflow was measured quarterly at two sites on Wissahickon Creek from December 2000 through September 2002. Geophysical logging identified water-bearing zones associated with

  1. Geohydrology of the Cerro Prieto geothermal aquifer

    SciTech Connect

    Sanchez R, J.; de la Pena L, A.

    1981-01-01

    The most recent information on the Cerro Prieto geothermal aquifer is summarized, with special emphasis on the initial production zone where the wells completed in the Alpha aquifer are located. These wells produce steam for power plant units 1 and 2. Brief comments also are made on the Beta aquifer, which underlies the Alpha aquifer in the Cerro Prieto I area and which extends to the east to what is known as the Cerro Prieto II and Cerro Prieto III areas. The location of the area studied is shown. The Alpha and Beta aquifers differ in their mineralogy and cementing mineral composition, temperatures, and piezometric levels. The difference in piezometric levels indicates that there is no local communication between the two aquifers. This situation has been verified by a well interference test, using well E-1 as a producer in the Beta aquifer and well M-46 as the observation well in the Alpha aquifer. No interference between them was observed. Information on the geology, geohydrology, and geochemistry of Cerro Prieto is presented.

  2. Ambient Flow and Heterogeneity in Multi-Aquifer Wells

    NASA Astrophysics Data System (ADS)

    Hart, D. J.; Gotkowitz, M. B.; Luczaj, J. A.

    2009-12-01

    these high conductivity zones were due to fracturing, some type of dissolution or, perhaps, washout of poorly cemented sandstone. The third example was a more complex hydrogeologic system consisting of a stacked sequence of five hydrogeologic units: aquifer (St Peter sandstone)-aquitard (Tunnel City Group)-aquifer (Wonewoc sandstone)-aquitard (Eau Claire shale)-aquifer (Mt Simon sandstone). In this well, the very high conductivity zones were also present as shown by the abrupt changes in borehole flow in the upper aquifer. In addition, there was divergent flow out of the middle aquifer upward into the upper aquifer and also downward into the lower aquifer. This result was subsequently corroborated by packer tests that showed the highest farfield heads to be in the middle aquifer with lower heads in the upper and lower aquifers. The spinner flow meter logs characterize the variability of these aquifer and aquitard systems in Wisconsin. This knowledge can then be applied to groundwater issues such as contaminant transport, well head protection, or regional water supply issues.

  3. Simulated effects of Lower Floridan aquifer pumping on the Upper Floridan aquifer at Pooler, Chatham County, Georgia

    USGS Publications Warehouse

    Cherry, Gregory S.; Clarke, John S.

    2013-01-01

    A revised regional groundwater-flow model was used to assess the potential effects on the Upper Floridan aquifer (UFA) of pumping the Lower Floridan aquifer (LFA) from a new well (35Q069) located at the City of Pooler in coastal Georgia near Savannah. The spatial resolution of the original regional, steady-state, groundwater-flow model was increased to incorporate detailed hydrogeologic information resulting from field investigations at Pooler and existing wells in the area. Simulation results using the U.S. Geological Survey finite-difference code MODFLOW indicated that long-term pumping at a rate of 780 gallons per minute (gal/min) from the LFA well 35Q069 would cause a maximum drawdown of about 2.52 feet (ft) in the UFA (scenario A). This maximum drawdown in the UFA was greater than the observed draw-down of 0.9 ft in the 72-hour aquifer test, but this is expected because the steady-state simulated drawdown represents long-term pumping conditions. Model results for scenario A indicate that drawdown in the UFA exceeded 1 ft over a 163-square-mile (mi2) area. Induced vertical leakage from the UFA provided about 98 percent of the water to the LFA; the area within 1 mile of the pumped well contributed about 81 percent of the water pumped. Simulated pumping changed regional water-budget components slightly and redistributed flow among model layers, namely increasing downward leakage in all layers, decreasing upward leakage in all layers above the LFA, increasing inflow to and decreasing outflow from lateral specified-head boundaries in the UA and LFA, and increasing the volume of induced recharge from the general head boundary to outcrop units. An additional two groundwater-pumping scenarios were run to establish that a linear relation exists between pumping rates of the LFA well 35Q069 (varied from 390 to 1,042 gal/min) and amount of drawdown in the UFA and LFA. Three groundwater-pumping scenarios were run to evaluate the amount of UFA pumping (128 to 340 gal

  4. Cyclic injection, storage, and withdrawal of heated water in a sandstone aquifer at St. Paul, Minnesota: Analysis of thermal data and nonisothermal modeling of short-term test cycles

    USGS Publications Warehouse

    Miller, Robert T.; Delin, G.N.

    1994-01-01

    A three-dimensional, anisotropic, nonisothermal, ground-water-flow, and thermal-energy-transport model was constructed to simulate the four short-term test cycles. The model was used to simulate the entire short-term testing period of approximately 400 days. The only model properties varied during model calibration were longitudinal and transverse thermal dispersivities, which, for final calibration, were simulated as 3.3 and 0.33 meters, respectively. The model was calibrated by comparing model-computed results to (1) measured temperatures at selected altitudes in four observation wells, (2) measured temperatures at the production well, and (3) calculated thermal efficiencies of the aquifer. Model-computed withdrawal-water temperatures were within an average of about 3 percent of measured values and model-computed aquifer-thermal efficiencies were within an average of about 5 percent of calculated values for the short-term test cycles. These data indicate that the model accurately simulated thermal-energy storage within the Franconia-Ironton-Galesville aquifer.

  5. Characteristics and properties of the basin-fill aquifer determined from three test wells west of Albuquerque, Bernalillo County, New Mexico

    USGS Publications Warehouse

    Wilkins, D.W.

    1987-01-01

    Three test wells were drilled west of Albuquerque; two are on the mesa west of the city, the third well is near the Rio Grande flood plain, west of the river. Test well 1, was drilled to a depth of 1,204 ft. Transmissivity of perforated intervals in the alluvial zone (980-1121 ft) ranged from 3.1 to 3.9 ft sq/day, and horizontal hydraulic conductivity from .02 to .03 ft/day. Vertical hydraulic conductivity of the semiconfining layer between the alluvial and volcanic zones is estimated to range from .00031 to .0031 ft/day. Transmissivity of the volcanic zone (1139-1179 ft) is about 81 ft sq/day, and horizontal hydraulic conductivity is about 2.0 ft/day. Dissolved-iron and manganese concentrations exceed recommended constituent limits for a public water supply. Vertical flow is upward; the potentiometric surface in the volcanic zone is about 2 ft higher than in the alluvial zone. Water levels are about 883 ft below land surface. Test well 2 was drilled to a depth of 1,828 ft below land surface with seven intervals open to the aquifer. During development, fine sand and silt entered the casing, filling it to a depth of 1,500 ft. The dissolved-cadmium concentration exceeds the maximum contaminant level and the dissolved-manganese concentration exceeds the recommended constituent limit for a public water supply. The vertical flow gradient is downward; the potentiometric surface in the middle and lower zones is about 17 ft lower than in the upper zones. Depth to water in the upper zone is about 767 below land surface and in the lower two zones the depth to water is about 784 ft below land surface. Test well 3 was drilled to a depth of 1,050 ft. Only the interval from 490 to 590 ft below land surface could be used to calculate transmissivity which was about 1,300 ft sq/day; horizontal hydraulic conductivity is about 13 ft/day. Quality of water is acceptable for a public water supply. Vertical flow is downward; the potentiometric surface in the deepest interval is about 7

  6. Implementing ground surface deformation tools to characterize field-scale properties of a fractured aquifer during a short hydraulic test

    NASA Astrophysics Data System (ADS)

    Schuite, Jonathan; Longuevergne, Laurent; Bour, Olivier; Boudin, Frédérick; Durand, Stéphane

    2016-04-01

    In naturally fractured reservoirs, fluid flow is governed by the structural and hydromechanical properties of fracture networks or conductive fault zones. In order to ensure a sustained exploitation of resources or to assess the safety of underground storage, it is necessary to evaluate these properties. As they generally form highly heterogeneous and anisotropic reservoirs, fractured media may be well characterized by means of several complementary experimental methods or sounding techniques. In this framework, the observation of ground deformation has been proved useful to gain insight of a fractured reservoir's geometry and hydraulic properties. Commonly, large conductive structures like faults can be studied from surface deformation from satellite methods at monthly time scales, whereas meter scale fractures have to be examined under short-term in situ experiments using high accuracy intruments like tiltmeters or extensometers installed in boreholes or at the ground's surface. To the best of our knowledge, the feasability of a field scale (~ 100 m) characterization of a fractured reservoir with geodetic tools in a short term experiment has not yet been addressed. In the present study, we implement two complementary ground surface geodetic tools, namely tiltmetry and optical leveling, to monitor the deformation induced by a hydraulic recovery test at the Ploemeur hydrological observatory (France). Employing a simple purely elastic modeling approach, we show that the joint use of time constraining data (tilt) and spatially constraining data (vertical displacement) makes it possible to evaluate the geometry (dip, root depth and lateral extent) and the storativity of a hydraulically active fault zone, in good agreement with previous studies. Hence we demonstrate that the adequate use of two complementary ground surface deformation methods offer a rich insight of large conductive structure's properties using a single short term hydraulic load. Ground surface

  7. Results of borehole geophysical logging and aquifer-isolation tests conducted in the John Wagner and Sons, Inc former production well, Ivyland, Pennsylvania

    USGS Publications Warehouse

    Sloto, Ronald A.

    1997-01-01

    A suite of borehole geophysical logs and heat-pulse-flowmeter measurements run in the former production well at the John Wagner and Sons, Inc. plant indicate two zones of borehole flow. In the upper part of the well, water enters the borehole through a fracture at 90 ft (feet) below floor level, moves upward, and exits the borehole through a fracture at 72 ft below floor level. Water also enters the borehole through fractures at 205-213, 235, and 357 ft below floor level; moves downward; and exits the borehole through fractures at 450-459, 468-470, and 483-490 ft below floor level. Five zones were selected for aquifer-isolation (packer) tests on the basis of borehole geophysical logs. The zones were isolated using a straddle-packer assembly. The lowermost three zones (below 248, 223 to 248, and 198 to 223 ft below floor level) were hydraulically isolated from zones above and below. Specific capacities were 0.12, 0.034, and 0.15 gallons per minute per foot, respectively. The hydrograph from zone 2 (223 to 248 ft below floor level) showed interference from a nearby pumping well. For the upper two zones (81 to 106 and 57 to 81 ft below floor level), similar drawdowns in the isolated zone and the zones above and below the isolated zone indicate that these fractures are hydraulically connected outside the borehole in the unconfined part of the Stockton Formation. The specific capacity of zones 4 and 5 are similar--0.82 and 0.61, respectively.

  8. Assessment of the value of microgravity to estimate the principal directions of the anisotropic transmissivity of aquifers from pumping tests: A study using a Hough transform based automatic algorithm

    NASA Astrophysics Data System (ADS)

    Fernández-Álvarez, José-Paulino; González-Quirós, Andrés; Rubio-Melendi, David

    2016-11-01

    Estimation of the hydraulic parameters of an aquifer is usually performed via interpretation of pumping tests. This invasive method requires drilling both pumping and observation wells. As the process is expensive, only a single pumping well and one or two observation wells or piezometers are generally drilled, at most. The interpretation is done assuming aquifer isotropy and homogeneity. However, in many aquifers, horizontal anisotropy in hydraulic conductivity greatly affects the flow regime. Its disregard may lead to important misinterpretations, especially for environmental impact assessments. This paper studies the capabilities of gravity for the identification and determination of the principal directions of anisotropy. This has been automatized using a methodology based on the Hough Transform. The results show how a microgravity survey could be an adequate and relatively cheap monitoring tool for the identification of anisotropy. This is valuable information that can be used in the decision making process for performing or discarding additional studies. Even more, the presented methodology can be extended to other studies in which contour maps are used to identify directionality in any process or property.

  9. Aquifer transmissivity of porous media from resistivity data

    NASA Astrophysics Data System (ADS)

    Niwas, Sri; Singhal, D. C.

    1985-11-01

    To optimize the information/cost ratio and avoid the indiscriminate and excessive use of drilling and pump testing to calculate aquifer transmissivity an analytical relationship between modified transverse resistance and aquifer transmissivity has been developed for estimating transmissivity from resistivity sounding data. The relation takes into consideration the variation in the quality of groundwater. The relation has been tested successfully for the glacial aquifers of Rhode Island, U.S.A. and alluvial aquifers of three different areas of Uttar Pradesh, India. The practical applicability of the relation lies in the fact that if hydraulic conductivity is known for any reference point of a porous homogeneous aquifer, one can get fairly good idea of the transmissivity of the aquifer at other locations within a basin, from surface geo-electrical measurements.

  10. 16 CFR 1500.42 - Test for eye irritants.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... noted below. (2) The eyes are examined and the grade of ocular reaction is recorded at 24, 48, and 72 hours. Reading of reactions is facilitated by use of a binocular loupe, hand slit-lamp, or other expert... positive reaction if the test substance produces at any of the readings ulceration of the cornea...

  11. 16 CFR 1500.42 - Test for eye irritants.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... noted below. (2) The eyes are examined and the grade of ocular reaction is recorded at 24, 48, and 72 hours. Reading of reactions is facilitated by use of a binocular loupe, hand slit-lamp, or other expert... positive reaction if the test substance produces at any of the readings ulceration of the cornea...

  12. Evaluation of geophysical logs and aquifer-isolation tests, Phase III, August 2002 to March 2004, Crossley Farm superfund site, Hereford township, Berks County, Pennsylvania

    USGS Publications Warehouse

    Conger, Randall W.; Low, Dennis J.

    2006-01-01

    Between August 2002 and March 2004, geophysical logging was conducted in 23 boreholes at the Crossley Farm Superfund Site, Hereford Township, Berks County, Pa., to determine the water-producing zones, water-receiving zones, zones of vertical-borehole flow, and fracture orientation where applicable. The boreholes ranged in depth from 71 to 503 ft(feet) below land surface. The geophysical logging determined the placement of well screens and packers, which allow monitoring and sampling of water-bearing zones in the fractured bedrock so the horizontal and vertical distribution of contaminated ground water migrating from known sources could be determined. Geophysical logging included collection of caliper (22 boreholes), fluid-temperature (17 boreholes),single-point-resistance (17 boreholes), natural-gamma (17 boreholes), fluid-flow (18 boreholes), and acoustic-televiewer (13 boreholes) logs. Caliper and acoustic-televiewer logs were used to locate fractures, joints, and weathered zones. Inflections on fluid-temperature and single-point-resistance logs indicated possible water-bearing zones, and flowmeter measurements verified these locations. Single-point-resistance, natural-gamma, and geologist logs provided information on stratigraphy; the geologist log also provided information on the location of possible water-producing zones. Borehole geophysical logging and heatpulse flowmetering indicated active flow in 10 boreholes. Seven of the boreholes are in ground-water discharge areas and three boreholes are in ground-water recharge areas. Heatpulse flowmetering, in conjunction with the geologist logs, indicates lithologic contacts (changes in lithology from a gneiss dominated by quartz-plagioclase-feldspar mineralogy to a gneiss dominated by hornblende mineralogy) are typically fractured, permeable, and effective transmitters of water. Single-well, aquifer-isolation (packer) tests were performed on two boreholes. Packers were set at depths ranging from 210 to 465 ft

  13. Aquifer Thermal Energy Storage in the US

    NASA Astrophysics Data System (ADS)

    Kannberg, L. D.

    1985-06-01

    DOE has funded investigation of Aquifer Thermal Energy Storage (ATES) since 1975. The scope of the ATES investigation has encompassed numerical modeling, field testing, economic analyses, and evaluation of institutional issues. ATES has received the bulk of the attention because of its widespread potential in the US. US efforts are now concentrated on a high temperature (up to 150C) ATES field test on the St. Paul campus of the University of Minnesota. Four short-term test cycles and the first of two long-term test cycles have been completed at this site. Utilization of chill ATES to meet summer air conditioning demands has been monitored at two operating sites in Tuscaloosa, Alabama. The systems utilize a cooling tower to directly chill groundwater pumped from a water table aquifer for storage in the same aquifer. The first of the two systems has exhibited relatively poor performance. More comprehensive monitoring has recently been undertaken at another site.

  14. Potential environmental issues of CO2 storage in deep saline aquifers: geochemical results from the Frio-I brine pilot test, Texas, USA

    SciTech Connect

    Kharaka, Dr. Yousif; Thordsen, Dr. James; Hovorka, Dr. Susan; Nance, Dr. H Seay; Cole, David R; Phelps, Tommy Joe; Knauss, Dr. Kevin; Chialvo, Ariel A

    2009-01-01

    Sedimentary basins in general and deep saline aquifers in particular, are being investigated as possible repositories for large volumes of anthropogenic CO2 that must be sequestered to mitigate global warming and related climate changes. To investigate the potential for the long-term storage of CO2 in such saline aquifers, 1600 t of CO2 were injected at 1500 m depth into a 24-m-thick C sandstone section of the Frio Formation, a regional aquifer in the U.S. Gulf Coast. Fluid samples obtained before CO2 injection from the injection well and an observation well 30 m up dip showed a Na-Ca-Cl type brine with ~93,000 mg/L TDS at saturation with CH4 at reservoir conditions; gas analyses show CH4 comprised ~95% of dissolved gas, but CO2 was low at 0.3%. Following CO2 breakthrough, 51 h after injection, samples showed sharp drops in pH (6.5 to 5.7), pronounced increases in alkalinity (100 to 3000 mg/L as HCO3) and in Fe (30 to 1100 mg/L), a slug of very high DOC values, and significant shifts in the isotopic compositions of H2O, DIC, and CH4. These data coupled with geochemical modeling indicate rapid dissolution of minerals, especially calcite and iron oxyhydroxides caused by lowered pH (initially ~3.0 at subsurface conditions) of the brine in contact with supercritical CO2.

  15. RECOVERY OF FRESHWATER STORED IN SALINE AQUIFERS IN PENINSULAR FLORIDA.

    USGS Publications Warehouse

    Merritt, Michael L.

    1986-01-01

    Subsurface freshwater storage has been operationally tested at seven sites in central and south Florida. Injection was into a high chloride water aquifer at six sites, and into a high sulfate water aquifer at the seventh. Recovery efficiency has ranged from 0 to 75 percent in high chloride water aquifers, and has exceeded 100 percent in the high sulfate water aquifer. Computer modeling techniques were used to examine the geohydrologic, design, and management factors governing the recovery efficiency of subsurface freshwater storage. The modeling approach permitted many combinations of geohydrologic and operational conditions to be studied at relatively low cost.

  16. Interpretation of Borehole Geophysical Logs, Aquifer-Isolation Tests, and Water-Quality Data for Sites 1, 3, and 5 at the Willow Grove Naval Air Station/Joint Reserve Base, Horsham Township, Montgomery County, Pennsylvania: 2005

    USGS Publications Warehouse

    Sloto, Ronald A.

    2007-01-01

    Borehole geophysical logging, heatpulse-flowmeter measurements, borehole television surveys, and aquifer-isolation tests were conducted in 2005 at the Willow Grove Naval Air Station/Joint Reserve Base (NAS/JRB) in Horsham Township, Montgomery County, Pa. This study was done by the U.S. Geological Survey (USGS) in cooperation with the U.S. Navy in support of hydrogeological investigations to address ground-water contamination. Data collected for this study are valuable for understanding ground-water flow in the Stockton Formation at the local and regional scale. The Willow Grove NAS/JRB is underlain by the Stockton Formation, which consists of sedimentary rocks of Triassic age. The rocks of the Stockton Formation form a complex, heterogeneous aquifer with partially connected zones of high permeability. Borehole geophysical logs, heatpulse-flowmeter measurements, and borehole television surveys made in seven boreholes ranging from 70 to 350 ft deep were used to identify potential water-producing fractures and fracture zones and to select intervals for aquifer-isolation tests. An upward vertical hydraulic gradient was measured in one borehole, a downward vertical hydraulic gradient was measured in four boreholes, both an upward and a downward vertical hydraulic gradient were measured in one borehole, and no flow was measurable in one borehole. The aquifer-isolation tests isolated 30 discrete fractures in the seven boreholes for collection of depth-discrete hydraulic and water-quality data. Of the 30 fractures identified as potentially water producing, 26 fractures (87 percent) produced more than 1 gallon per minute of water. The specific capacity of the isolated intervals producing more than 1 gallon per minute ranged from 0.02 to 5.2 gallons per minute per foot. There was no relation between specific capacity and depth of the fracture. Samples for analysis for volatile organic compounds were collected from each isolated zone. Tetrachloroethylene (PCE) was the most

  17. Long-term pumping test to study the impact of an open-loop geothermal system on seawater intrusion in a coastal aquifer: the case study of Bari (Southern Italy)

    NASA Astrophysics Data System (ADS)

    Clementina Caputo, Maria; Masciale, Rita; Masciopinto, Costantino; De Carlo, Lorenzo

    2016-04-01

    The high cost and scarcity of fossil fuels have promoted the increased use of natural heat for a number of direct applications. Just as for fossil fuels, the exploitation of geothermal energy should consider its environmental impact and sustainability. Particular attention deserves the so-called open loop geothermal groundwater heat pump (GWHP) system, which uses groundwater as geothermal fluid. From an economic point of view, the implementation of this kind of geothermal system is particularly attractive in coastal areas, which have generally shallow aquifers. Anyway the potential problem of seawater intrusion has led to laws that restrict the use of groundwater. The scarcity of freshwater could be a major impediment for the utilization of geothermal resources. In this study a new methodology has been proposed. It was based on an experimental approach to characterize a coastal area in order to exploit the low-enthalpy geothermal resource. The coastal karst and fractured aquifer near Bari, in Southern Italy, was selected for this purpose. For the purpose of investigating the influence of an open-loop GWHP system on the seawater intrusion, a long-term pumping test was performed. The test simulated the effects of a prolonged withdrawal on the chemical-physical groundwater characteristics of the studied aquifer portion. The duration of the test was programmed in 16 days, and it was performed with a constant pumping flowrate of 50 m3/h. The extracted water was outflowed into an adjacent artificial channel, by means of a piping system. Water depth, temperature and electrical conductivity of the pumped water were monitored for 37 days, including also some days before and after the pumping duration. The monitored parameters, collected in the pumping and in five observation wells placed 160 m down-gradient with respect to the groundwater flow direction, have been used to estimate different scenarios of the impact of the GWHP system on the seawater intrusion by mean of a

  18. Productivity of an unconfined aquifer as related to carbonate facies: the Coral Reef Aquifer of Collier County, Florida

    SciTech Connect

    Missimer, T.M.

    1985-01-01

    A 3-year investigation of the shallow, unconfined Coral Reef Aquifer of northern Collier County, Florida, has revealed the relationship of carbonate lithofacies to the transmissivity and specific yield of the aquifer. The geology of the aquifer was studied using cores, test wells, and both surface and borehole geophysics. Numerous aquifer performance tests were conducted to measure the hydraulic coefficients of the aquifer. The Coral Reef Aquifer consists of a surficial quartz sand mantel from 4 to 20 feet thick underlain by 24 to 70 feet of limestone. Four predominant lithofacies were found in the limestone: moldic arenaceous, molluscan packstone; corraline, moldic boundstone,; molluscan wackestone; and unconsolidated, agrillaceous wackestone. The base of the aquifer is formed by a low permeability, green dolosilt. Transmissivity values measured over a 12-square mile area ranged from 59,000 to 1,550,000 gpd/ft. The highest transmissivity values were associated with the occurrence of molluscan packstones. Estimated porosities in the molluscan packstone ranged up to 65% compared to 40% or less in the other lithofacies. The transmissivity of the aquifer was dependent primarily on the occurrence of the molluscan packstones and not greatly dependent on the overall aquifer thickness.

  19. A progress report on results of test drilling and ground-water investigations of the Snake Plain aquifer, southeastern Idaho: Part 3: Lake Walcott-Bonanza Lake area

    USGS Publications Warehouse

    Crosthwaite, E.G.

    1974-01-01

    Direct-current resistivity soundings and exploratory drilling suggest that the basalt of the Snake River Group is relatively thin in the area along the Snake River that is topographically suitable for pumping large quantities of ground water in exchange for surface water. The formations underlying the Snake River Group appear to have low permeability and probably would not yield large amounts of water. Previous studies have indicated that the southern edge of the Snake Plain aquifer extended to the Snake River. Data presented in this report implies that, in general, the southern boundary should, in fact, be several miles north of the river.

  20. Comparison of the Capacity of Different Jump and Sprint Field Tests to Detect Neuromuscular Fatigue.

    PubMed

    Gathercole, Rob J; Sporer, Ben C; Stellingwerff, Trent; Sleivert, Gord G

    2015-09-01

    Different jump and sprint tests have been used to assess neuromuscular fatigue, but the test with optimal validity remains to be established. The current investigation examined the suitability of vertical jump (countermovement jump [CMJ], squat jump [SJ], drop jump [DJ]) and 20-m sprint (SPRINT) testing for neuromuscular fatigue detection. On 6 separate occasions, 11 male team-sport athletes performed 6 CMJ, SJ, DJ, and 3 SPRINT trials. Repeatability was determined on the first 3 visits, with subsequent 3 visits (0-, 24-, and 72-hour postexercise) following a fatiguing Yo-Yo running protocol. SPRINT performance was most repeatable (mean coefficient of variation ≤2%), whereas DJ testing (4.8%) was significantly less repeatable than CMJ (3.0%) and SJ (3.5%). Each test displayed large decreases at 0-hour (33 of 49 total variables; mean effect size = 1.82), with fewer and smaller decreases at 24-hour postexercise (13 variables; 0.75), and 72-hour postexercise (19 variables; 0.78). SPRINT displayed the largest decreases at 0-hour (3.65) but was subsequently unchanged, whereas SJ performance recovered by 72-hour postexercise. In contrast, CMJ and DJ performance displayed moderate (12 variables; 1.18) and small (6 variables; 0.53) reductions at 72-hour postexercise, respectively. Consequently, the high repeatability and immediate and prolonged fatigue-induced changes indicated CMJ testing as most suitable for neuromuscular fatigue monitoring. PMID:26308829

  1. Comparison of the Capacity of Different Jump and Sprint Field Tests to Detect Neuromuscular Fatigue.

    PubMed

    Gathercole, Rob J; Sporer, Ben C; Stellingwerff, Trent; Sleivert, Gord G

    2015-09-01

    Different jump and sprint tests have been used to assess neuromuscular fatigue, but the test with optimal validity remains to be established. The current investigation examined the suitability of vertical jump (countermovement jump [CMJ], squat jump [SJ], drop jump [DJ]) and 20-m sprint (SPRINT) testing for neuromuscular fatigue detection. On 6 separate occasions, 11 male team-sport athletes performed 6 CMJ, SJ, DJ, and 3 SPRINT trials. Repeatability was determined on the first 3 visits, with subsequent 3 visits (0-, 24-, and 72-hour postexercise) following a fatiguing Yo-Yo running protocol. SPRINT performance was most repeatable (mean coefficient of variation ≤2%), whereas DJ testing (4.8%) was significantly less repeatable than CMJ (3.0%) and SJ (3.5%). Each test displayed large decreases at 0-hour (33 of 49 total variables; mean effect size = 1.82), with fewer and smaller decreases at 24-hour postexercise (13 variables; 0.75), and 72-hour postexercise (19 variables; 0.78). SPRINT displayed the largest decreases at 0-hour (3.65) but was subsequently unchanged, whereas SJ performance recovered by 72-hour postexercise. In contrast, CMJ and DJ performance displayed moderate (12 variables; 1.18) and small (6 variables; 0.53) reductions at 72-hour postexercise, respectively. Consequently, the high repeatability and immediate and prolonged fatigue-induced changes indicated CMJ testing as most suitable for neuromuscular fatigue monitoring.

  2. A progress report on results of test drilling and ground-water investigations of the Snake Plain aquifer, southeastern Idaho: Part 1: Mud Lake Region, 1969-70 and Part 2: Observation Wells South of Arco and West of Aberdeen

    USGS Publications Warehouse

    Crosthwaite, E.G.

    1973-01-01

    The results of drilling test holes to depths of approximately 1,000 feet in the Mud Lake region show that a large part of the region is underlain by both sedimentary deposits and basalt flows. At some locations, predominantly sedimentary deposits were penetrated; at others, basalt flows predominated. The so-called Mud Lake-Market Lake barrier denotes a change in geology. From the vicinity of the barrier area, as described by Stearns, Crandall, and Steward (1938, p. 111), up the water-table gradient for at least a few tens of miles, the saturated geologic section consists predominantly of beds of sediments that are intercalated with numerous basalt flows. Downgradient from the barrier, sedimentary deposits are not common and practically all the water-bearing formations are basalt, at least to the depths explored so far. Thus, the barrier is a transition zone from a sedimentary-basaltic sequence to a basaltic sequence. The sedimentary-basaltic sequence forms a complex hydrologic system in which water occurs under water-table conditions in the upper few tens of feet of saturated material and under artesian conditions in the deeper material in the southwest part of the region. The well data indicate that southwest of the barrier, artesian pressures are not significant. Southwest of the barrier, few sedimentary deposits occur in the basalt section and, as described by Mundorff, Crosthwaite, and Kilburn (1964). ground water occurs in a manner typical of the Snake Plain aquifer. In several wells, artesian pressures are higher in the deeper formations than in the shallower ones, but the reverse was found in a few wells. The available data are not adequate to describe the water-bearing characteristics of the artesian aquifer nor the effects that pumping in one zone would have on adjacent zones. The water-table aquifer yields large quantities of water to irrigation wells.

  3. Hydraulic Tomography to Characterization of Heterogeneity of Unconfined Aquifers

    NASA Astrophysics Data System (ADS)

    Zhu, J.; Yeh, T. J.

    2008-12-01

    Analytical models are the most widely used methods for analyzing pumping tests in unconfined aquifers. However, one major group analytical models assume instantaneous and complete drainage at the water table and therefore are inadequate to account for gradual drainage of water from the vadose zone due to pumping; the other major group analytical models use an exponential function of drawdown at the water table to account for gradual drainage and are subsequently limited to represent the highly non-linear flow in the vadose zone. Moreover, both models assume aquifer homogeneity while the natural aquifers are inherently heterogeneous. Recently emerged Hydraulic tomography (HT) is a cost-effective method for mapping spatial distribution of aquifer hydraulic properties. HT takes advantage of the power of numerical models and fuses information from multiple cross-hole tests conducted at different locations to image aquifers in great details. In this study, we apply HT concept to unconfined aquifers. To accurately simulate the flow behavior due to a HT survey in an unconfined aquifer, a fully three dimensional variably saturated flow model based on mixed form of Richards equation is used. Pressure responses in both saturated and unsaturated zones are used to estimate spatial variations of hydraulic conductivity, specific storage, and soil water constitutive model parameters through a sequential successive linear estimator. A systematic approach that uses wavelet analysis, least-square method, and fuzzy similarity compassion is applied for data denoising, statistic inputs, convergence, and performance assessment. A cross-correlation is also performed to investigate the relation between pressure change and different parameters. The HT method for unconfined aquifers is tested in a synthetic aquifer. The tests show that the proposed HT method effectively maps heterogeneity of the unconfined aquifer and predicts the vadose zone responses due to a pumping test more accurately

  4. Basement Aquifers : How Useful Are Gravity Data ?

    NASA Astrophysics Data System (ADS)

    Genthon, P.; Mouhouyouddine, A. H.; Hinderer, J.; Hector, B.; Yameogo, S.

    2014-12-01

    Gravity data with a few microgal precision were proved to be able to constrain the specific yield of various kinds of aquifer in West Africa from annual fluctuations of both the gravimetric and piezometric signals (Pfeffer et al., Geophys. J. Int., 2011; Hector et al., Geophys. J. Int., 2013). However some recent papers reported a disappointing potential of gravity measurements during a pumping experiment in a sandy aquifer (Blainey et al., WRR, 2007; Herckenrath et al., WRR, 2012) and their poor ability in constraining the transmissity and specific yield of the aquifer, which are the parameters to which pumping tests give access. Fresh basement rocks present generally a null porosity and the structure of basement aquifers is given by the weathering profile. In tropical climate, this profile consists of a few tens meter thick saprolite layer, with noticeable porosity but low permeability overlying the weathering front. This weathering front includes in many instances a fractured medium and presents a high permeability with variable porosity. It is hardly sampled in coring experiments. We present some numerical simulation results on the ability of gravity to constrain the transmissivity of this medium. Due to poroelasticity of clay minerals in the saprolite, soil subsidence is expected to occur during pumping with a significant gravity effect. Gravity measurements have therefore to be completed with leveling data at a millimetric precision. We present first the results of numerical modeling of the gravity and subsidence for a theoretical horizontally stratified basement aquifer, and show that gravity and leveling are able to provide independently the poroelasticity coefficient and a single transmissivity coefficient for the bottom of the aquifer, if the properties of the upper saprolites are known. We will discuss then the general case, where the aquifer presents a vertical fracture where the weathering profile thickens.

  5. Distribution of methyl tert-butyl ether (MTBE) and selected water-quality constituents in the surficial aquifer at the Dover National Test Site, Dover Air Force Base, Delaware, 2001

    USGS Publications Warehouse

    Stewart, Marie; Guertal, William R.; Barbaro, Jeffrey R.; McHale, Timothy J.

    2004-01-01

    A joint study by the Dover National Test Site, Dover Air Force Base, Delaware, and the U.S. Geological Survey was conducted from June 27 through July 18, 2001, to determine the spatial distribution of the gasoline oxygenate additive methyl tert-butyl ether and selected water-quality constituents in the surficial aquifer underlying the Dover National Test Site. This report provides a summary assessment of the distribution of methyl tert-butyl ether and a preliminary screening of selected constituents that may affect natural attenuation and remediation demonstrations at the Dover National Test Site. The information gathered during this study is designed to assist potential remedial investigators who are considering conducting a methyl tert-butyl ether remedial demonstration at the test site. In addition, the study supported a planned enhanced bioremediation demonstration and assisted the Dover National Test Site in identifying possible locations for future methyl tert-butyl ether remediation demonstrations. A direct-push drill rig was used to collect a total of 147 ground-water samples (115 VOC samples and 32 quality-assurance samples) at varying depths. Volatile organic compounds were above the method reporting limits in 59 of the 115 ground-water samples. The concentrations ranged from below detection limits to maximum values of 12.4 micrograms per liter of cis-1,2-dichloro-ethene, 1.14 micrograms per liter of trichloro-ethene, 2.65 micrograms per liter of tetrachloro-ethene, 1,070 micrograms per liter of methyl tert-butyl ether, 4.36 micrograms per liter of benzene, and 1.8 micrograms per liter of toluene. Vinyl chloride, ethylbenzene, p,m-xylene, and o-xylene were not detected in any of the samples collected during this investigation. Methyl tert-butyl ether was detected in 47 of the 115 ground-water samples. The highest concentrations of methyl tert-butyl ether were detected in the surficial aquifer from ?4.6 to 6.4 feet mean sea level; however, methyl tert

  6. Simulation of aquifer tests and ground-water flowpaths at the local scale in fractured shales and sandstones of the Brunswick Group and Lockatong Formation, Lansdale, Montgomery County, Pennsylvania

    USGS Publications Warehouse

    Goode, Daniel J.; Senior, Lisa A.

    2000-01-01

    The U.S. Geological Survey, as part of technical assistance to the U.S. Environmental Protection Agency, has constructed and calibrated models of local-scale ground-water flow in and near Lansdale, Pa., where numerous sources of industrial contamination have been consolidated into the North Penn Area 6 Superfund Site. The local-scale models incorporate hydrogeologic structure of northwest-dipping beds with uniform hydraulic properties identified in previous studies. Computations associated with mapping the dipping-bed structure into the three-dimensional model grid are handled by a preprocessor using a programmed geographic information system (GIS). Hydraulic properties are identified by calibration of the models using measured water levels during pumping and recovery from aquifer tests at three sites. Reduced flow across low-permeability beds is explicitly simulated. The dipping high-permeability beds are extensive in the strike direction but are of limited extent in the dip direction. This model structure yields ground-water-flow patterns characteristic of anisotropic aquifers; preferred flow is in the strike direction. The transmissivities of high-permeability beds in the local-scale models range from 142 to 1,900 ft2/d (feet squared per day) (13 to 177 m2/d). The hydraulic conductivities of low-permeability parts of the aquifer range from 9.6 x 10-4 to 0.26 ft/d (feet per day) (2.9 x 10-4 to 0.079 m/d). Storage coefficients and specific storage are very low, indicating the confined nature of the aquifer system. The calibrated models are used to simulate contributing areas of wells under alternative, hypothetical ground-water-management practices. Predictive contributing areas indicate the general characteristics of ground-water flow towards wells in the Lansdale area. Recharge to wells in Lansdale generally comes from infiltration near the well and over an area that extends upgradient from the well. The contributing areas for two wells pumping at 10 gal

  7. Self-organized permeability in carbonate aquifers.

    PubMed

    Worthington, S R H; Ford, D C

    2009-01-01

    Advances over the past 40 years have resulted in a clear understanding of how dissolution processes in carbonate rocks enhance aquifer permeability. Laboratory experiments on dissolution rates of calcite and dolomite have established that there is a precipitous drop in dissolution rates as chemical equilibrium is approached. These results have been incorporated into numerical models, simulating the effects of dissolution over time and showing that it occurs along the entire length of pathways through carbonate aquifers. The pathways become enlarged and integrated over time, forming self-organized networks of channels that typically have apertures in the millimeter to centimeter range. The networks discharge at point-located springs. Recharge type is an important factor in determining channel size and distribution, resulting in a range of aquifer types, and this is well demonstrated by examples from England. Most carbonate aquifers have a large number of small channels, but in some cases large channels (i.e., enterable caves) can also develop. Rapid velocities found in ground water tracer tests, the high incidence of large-magnitude springs, and frequent microbial contamination of wells all support the model of self-organized channel development. A large majority of carbonate aquifers have such channel networks, where ground water velocities often exceed 100 m/d.

  8. Scale-Dependent Dispersion in a Stratified Granular Aquifer

    NASA Astrophysics Data System (ADS)

    Pickens, John F.; Grisak, Gerald E.

    1981-08-01

    The magnitude of longitudinal dispersivity in a sandy stratified aquifer was investigated using laboratory column and field tracer tests. The field investigations included two-single-well injection-withdrawal tracer tests using 131I and a two-well recirculating withdrawal-injection tracer test using 51Cr-EDTA. The tracer movement within the aquifer was monitored in great detail with multilevel point-sampling instrumentation. A constant value for dispersivity of 0.7 cm was found to be representative (and independent of travel distance) at the scale of an individual level within the aquifer. A dispersivity of 0.035 cm was determined from laboratory column tracer tests as a representative laboratory-scale value for sand from the field site. The scale effect observed between the laboratory dispersivity and the dispersivity from individual levels in the aquifer is caused by the greater inhomogeneity of the aquifer (e.g., laminations within individual layers) and the averaging caused by the groundwater sampling system. Full-aquifer dispersivities of 3 and 9 cm obtained from the single-well tests indicate a scale effect with the value obtained being dependent mainly on the effect of transverse migration of tracer between the layers and the total injection volume. The full-aquifer dispersivity of 50 cm from the two-well test is scale-dependent, controlled by the distance between the injection and withdrawal wells (8 m) and hydraulic conductivity distribution in the aquifer. Scale-dependent full-aquifer dispersivity expressions were derived relating dispersivity to the statistical properties of a stratified geologic system where the hydraulic conductivity distribution is normal, log normal or arbitrary. In the developed expressions, dispersivity is a linear function of the mean travel distance. Proportionality constants ranged from 0.041 to 0.256 for the hydraulic conductivity distributions obtained from the field tracer tests.

  9. A field test of tracer transport and organic contaminant elution in a stratified aquifer at the Rocky Mountain Arsenal (Denver, Colorado, U.S.A.)

    NASA Astrophysics Data System (ADS)

    Thorbjarnarson, Kathryn W.; Mackay, Douglas M.

    1997-01-01

    A tracer-elution experiment was conducted in a 9-m-thick alluvial sand aquifer at the Rocky Mountain Arsenal, Denver, Colorado, within an extensive 1,1,1-trichloroethene and trichloroethene plume. The forced-gradient flow field was controlled by an injection well and an extraction well separated by 8.4 m and aligned in the direction of the natural-gradient flow. Upon extraction, the contaminant-laden water was treated by air stripping and reinjected into the injection well. Iodide tracer was added to the injection flow during the initial 27.5 h of the experiment. Tracer transport and organic contaminant elution were monitored by four 0.15-m-screened drive points and a fully penetrating monitoring well. Relative permeabilities, dispersivities and retardation factors were estimated from tracer breakthrough and contaminant elution curves by the moment method and by curve-fitting with an advection-dispersion model. Tracer transport through the four strata sampled by the drive points indicated a permeability variation of three orders of magnitude. Contaminant elution was not observed in the lowest-permeability stratum monitored during the experiment. In all monitored strata, contaminant elution was controlled primarily by permeability effects on water flow and exhibited minimal retardation or desorption effects. The fully penetrating monitoring well exhibited a tracer response primarily from the more permeable strata with the addition of tracer from the less permeable strata producing an increased breakthrough spreading. This increased spreading or dispersion was reflected in a higher longitudinal dispersivity estimate (1.2 m assuming a homogeneous aquifer) than dispersivity estimates from the drive-point sampler tracer curves (ranging from 5 to 21 cm). Contaminant elution curves from the fully penetrating monitoring well exhibited an initial response primarily from the more permeable strata (rapid elution of contaminants) and provided no insight into the elution

  10. Potential environmental issues of CO2 storage in deep saline aquifers: Geochemical results from the Frio-I Brine Pilot test, Texas, USA

    USGS Publications Warehouse

    Kharaka, Y.K.; Thordsen, J.J.; Hovorka, S.D.; Seay, Nance H.; Cole, D.R.; Phelps, T.J.; Knauss, K.G.

    2009-01-01

    Sedimentary basins in general, and deep saline aquifers in particular, are being investigated as possible repositories for large volumes of anthropogenic CO2 that must be sequestered to mitigate global warming and related climate changes. To investigate the potential for the long-term storage of CO2 in such aquifers, 1600 t of CO2 were injected at 1500 m depth into a 24-m-thick "C" sandstone unit of the Frio Formation, a regional aquifer in the US Gulf Coast. Fluid samples obtained before CO2 injection from the injection well and an observation well 30 m updip showed a Na-Ca-Cl type brine with ???93,000 mg/L TDS at saturation with CH4 at reservoir conditions; gas analyses showed that CH4 comprised ???95% of dissolved gas, but CO2 was low at 0.3%. Following CO2 breakthrough, 51 h after injection, samples showed sharp drops in pH (6.5-5.7), pronounced increases in alkalinity (100-3000 mg/L as HCO3) and in Fe (30-1100 mg/L), a slug of very high DOC values, and significant shifts in the isotopic compositions of H2O, DIC, and CH4. These data, coupled with geochemical modeling, indicate corrosion of pipe and well casing as well as rapid dissolution of minerals, especially calcite and iron oxyhydroxides, both caused by lowered pH (initially ???3.0 at subsurface conditions) of the brine in contact with supercritical CO2. These geochemical parameters, together with perfluorocarbon tracer gases (PFTs), were used to monitor migration of the injected CO2 into the overlying Frio "B", composed of a 4-m-thick sandstone and separated from the "C" by ???15 m of shale and siltstone beds. Results obtained from the Frio "B" 6 months after injection gave chemical and isotopic markers that show significant CO2 (2.9% compared with 0.3% CO2 in dissolved gas) migration into the "B" sandstone. Results of samples collected 15 months after injection, however, are ambiguous, and can be interpreted to show no additional injected CO2 in the "B" sandstone. The presence of injected CO2 may

  11. 40 CFR 147.2908 - Aquifer exemptions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 24 2013-07-01 2013-07-01 false Aquifer exemptions. 147.2908 Section...-Class II Wells § 147.2908 Aquifer exemptions. (a) After notice and opportunity for a public hearing, the Administrator may designate any aquifer or part of an aquifer as an exempted aquifer. (b) An aquifer or...

  12. 40 CFR 147.2908 - Aquifer exemptions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 24 2012-07-01 2012-07-01 false Aquifer exemptions. 147.2908 Section...-Class II Wells § 147.2908 Aquifer exemptions. (a) After notice and opportunity for a public hearing, the Administrator may designate any aquifer or part of an aquifer as an exempted aquifer. (b) An aquifer or...

  13. 40 CFR 147.2908 - Aquifer exemptions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 23 2014-07-01 2014-07-01 false Aquifer exemptions. 147.2908 Section...-Class II Wells § 147.2908 Aquifer exemptions. (a) After notice and opportunity for a public hearing, the Administrator may designate any aquifer or part of an aquifer as an exempted aquifer. (b) An aquifer or...

  14. 40 CFR 147.2908 - Aquifer exemptions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Aquifer exemptions. 147.2908 Section...-Class II Wells § 147.2908 Aquifer exemptions. (a) After notice and opportunity for a public hearing, the Administrator may designate any aquifer or part of an aquifer as an exempted aquifer. (b) An aquifer or...

  15. 40 CFR 147.2908 - Aquifer exemptions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 23 2011-07-01 2011-07-01 false Aquifer exemptions. 147.2908 Section...-Class II Wells § 147.2908 Aquifer exemptions. (a) After notice and opportunity for a public hearing, the Administrator may designate any aquifer or part of an aquifer as an exempted aquifer. (b) An aquifer or...

  16. Sequence-Stratigraphic Analysis of the Regional Observation Monitoring Program (ROMP) 29A Test Corehole and Its Relation to Carbonate Porosity and Regional Transmissivity in the Floridan Aquifer System, Highlands County, Florida

    USGS Publications Warehouse

    Ward, W. C.; Cunningham, K.J.; Renken, R.A.; Wacker, M.A.; Carlson, J.I.

    2003-01-01

    An analysis was made to describe and interpret the lithology of a part of the Upper Floridan aquifer penetrated by the Regional Observation Monitoring Program (ROMP) 29A test corehole in Highlands County, Florida. This information was integrated into a one-dimensional hydrostratigraphic model that delineates candidate flow zones and confining units in the context of sequence stratigraphy. Results from this test corehole will serve as a starting point to build a robust three-dimensional sequence-stratigraphic framework of the Floridan aquifer system. The ROMP 29A test corehole penetrated the Avon Park Formation, Ocala Limestone, Suwannee Limestone, and Hawthorn Group of middle Eocene to Pliocene age. The part of the Avon Park Formation penetrated in the ROMP 29A test corehole contains two composite depositional sequences. A transgressive systems tract and a highstand systems tract were interpreted for the upper composite sequence; however, only a highstand systems tract was interpreted for the lower composite sequence of the deeper Avon Park stratigraphic section. The composite depositional sequences are composed of at least five high-frequency depositional sequences. These sequences contain high-frequency cycle sets that are an amalgamation of vertically stacked high-frequency cycles. Three types of high-frequency cycles have been identified in the Avon Park Formation: peritidal, shallow subtidal, and deeper subtidal high-frequency cycles. The vertical distribution of carbonate-rock diffuse flow zones within the Avon Park Formation is heterogeneous. Porous vuggy intervals are less than 10 feet, and most are much thinner. The volumetric arrangement of the diffuse flow zones shows that most occur in the highstand systems tract of the lower composite sequence of the Avon Park Formation as compared to the upper composite sequence, which contains both a backstepping transgressive systems tract and a prograding highstand systems tract. Although the porous and permeable

  17. Assessing the likely value of gravity and drawdown measurements to constrain estimates of hydraulic conductivity and specific yield during unconfined aquifer testing

    USGS Publications Warehouse

    Blainey, J.B.; Ferre, T. P. A.; Cordova, J.T.

    2007-01-01

    Pumping of an unconfined aquifer can cause local desaturation detectable with high-resolution gravimetry. A previous study showed that signal-to-noise ratios could be predicted for gravity measurements based on a hydrologic model. We show that although changes should be detectable with gravimeters, estimations of hydraulic conductivity and specific yield based on gravity data alone are likely to be unacceptably inaccurate and imprecise. In contrast, a transect of low-quality drawdown data alone resulted in accurate estimates of hydraulic conductivity and inaccurate and imprecise estimates of specific yield. Combined use of drawdown and gravity data, or use of high-quality drawdown data alone, resulted in unbiased and precise estimates of both parameters. This study is an example of the value of a staged assessment regarding the likely significance of a new measurement method or monitoring scenario before collecting field data. Copyright 2007 by the American Geophysical Union.

  18. Aquifer Testing Recommendations for Well 299-W15-225: Supporting Phase I of the 200-ZP-1 Groundwater Operable Unit Remedial Design

    SciTech Connect

    Spane, Frank A.; Newcomer, Darrell R.

    2009-03-10

    Aquifer characterization needs are currently being assessed to optimize pump-and-treat remedial strategies within the 200-ZP-1 Operable Unit (OU), specifically for the immediate area of the 241-TX-TY Tank Farm. Currently, 14 extraction wells are actively used in the Interim Record of Decision ZP-1 pump-and-treat system to remediate the existing groundwater contamination within this general area. Four of these wells (299-W15-40, 299-W15-43, 299-W15-44, and 299-W15-765) are targeted to remediate contamination within the immediate 241-TX-TY Tank Farm area. The major contaminant of concern (COC) for the 200-ZP-1 OU is carbon tetrachloride. Other COC’s include total chromium (trivalent [III] and hexavalent [VI], nitrate, trichloroethlyene, iodine-129, technetium-99, and tritium.

  19. Cold water aquifer storage

    NASA Astrophysics Data System (ADS)

    Reddell, D. L.; Davison, R. R.; Harris, W. B.

    1980-03-01

    A working prototype system is described in which water is pumped from an aquifer at 70 F in the winter time, chilled to a temperature of less than 50 F, injected into a ground-water aquifer, stored for a period of several months, pumped back to the surface in the summer time. A total of 8.1 million gallons of chilled water at an average temperature of 48 F were injected. This was followed by a storage period of 100 days. The recovery cycle was completed a year later with a total of 8.1 million gallons recovered. Approximately 20 percent of the chill energy was recovered.

  20. Unconsolidated Aquifers in Tompkins County, New York

    USGS Publications Warehouse

    Miller, Todd S.

    2000-01-01

    Unconsolidated aquifers consisting of saturated sand and gravel are capable of supplying large quantities of good-quality water to wells in Tompkins County, but little published geohydrologic inform ation on such aquifers is available. In 1986, the U.S.Geological Survey (USGS) began collecting geohydrologic information and well data to construct an aquifer map showing the extent of unconsolidated aquifers in Tompkins county. Data sources included (1) water-well drillers. logs; (2) highway and other construction test-boring logs; (3) well data gathered by the Tompkins County Department of Health, (4) test-well logs from geohydrologic consultants that conducted projects for site-specific studies, and (5) well data that had been collected during past investigations by the USGS and entered into the National Water Information System (NWIS) database. In 1999, the USGS, in cooperation with the Tompkins County Department of Planning, compiled these data to construct this map. More than 600 well records were entered into the NWIS database in 1999 to supplement the 350 well records already in the database; this provided a total of 950 well records. The data were digitized and imported into a geographic information system (GIS) coverage so that well locations could be plotted on a map, and well data could be tabulated in a digital data base through ARC/INFO software. Data on the surficial geology were used with geohydrologic data from well records and previous studies to delineate the extent of aquifers on this map. This map depicts (1) the extent of unconsolidated aquifers in Tompkins County, and (2) locations of wells whose records were entered into the USGS NWIS database and made into a GIS digital coverage. The hydrologic information presented here is generalized and is not intended for detailed site evaluations. Precise locations of geohydrologic-unit boundaries, and a description of the hydrologic conditions within the units, would require additional detailed, site

  1. Identifying connections in a fractured rock aquifer using ADFTs.

    PubMed

    Halihan, Todd; Love, Andrew; Sharp, John M

    2005-01-01

    Fractured rock aquifers are difficult to characterize because of their extremely heterogeneous nature. Developing an understanding of fracture network hydraulic properties in these aquifers is difficult and time consuming, and field testing techniques for determining the location and connectivity of fractures in these aquifers are limited. In the Clare Valley, South Australia, well interference is an important issue for a major viticultural area that uses a fractured aquifer. Five fracture sets exist in the aquifer, all dipping > 25 degrees . In this setting, we evaluate the ability of steady-state asymmetric dipole-flow tests (ADFTs) to determine the connections between a test well and a set of piezometers. The procedure involves dividing a test well into two chambers using a single packer and pumping fluid from the upper chamber to the lower chamber. By conducting a series of tests at different packer elevations, an "input" signal is generated in fracture zones connected to the test well. By monitoring the "output" response of the hydraulic dipole field at piezometers, the connectivity of the fractures between the test well and piezometers can be determined. Results indicate the test well used in this study is connected in a complex three-dimensional geometry, with drawdown occurring above and below areas of potentiometric buildup. The ADFT method demonstrates that the aquifer evaluated in this study cannot be modeled effectively on the well scale using continuum flow models. PMID:15882324

  2. Hydrogeology of the surficial aquifer system, Dade County, Florida

    USGS Publications Warehouse

    Fish, J.E.; Stewart, M.T.

    1991-01-01

    An investigation of the surficial aquifer system in Dade County, begun in 1983, is part of a regional study of the aquifer system in southeastern Florida. Test drilling for lithologic samples, flow measurements during drilling, aquifer testing, and analyses of earlier data permitted delineation of the hydraulic conductivity distribution (on hydrogeologic sections), the aquifers in the system, the generalized transmissivity distribution, and interpretation of the ground-water flow system. The surficial aquifer system, in which an unconfined ground-water flow system exists, is composed of the sediments from land surface downward to the top of a regionally extensive zone of sediments of low permeability called the intermediate confining unit. The aquifer system units, which vary in composition from clay-size sediments to cavernous limestone, are hydro stratigraphically divided into the Biscayne aquifer at the top; an intervening semiconfining unit that consists principally of clayey sand; a predominantly gray limestone aquifer in the Tamiami Formation in western and west-central Dade County; and sand or clayey sand near the base of the surficial aquifer system. The base of the surficial aquifer system ranges from a depth of about 175 to 210 feet below land surface in westernmost Dade County to greater than 270 feet in northeastern Dade County. Test drilling and aquifer-test data indicate a complex hydraulic conductivity distribution. Hydraulic conductivities of the very highly permeable zone of the Biscayne aquifer commonly exceed 10,000 feet per day; in the gray limestone aquifer, they range from 210 to 780 feet per day. Transmissivities of the surficial aquifer system vary locally but have a recognizable areal trend. Estimated values generally are about 300,000 feet squared per day or greater in nearly all of central and eastern Dade County. Transmissivity is lower to the west, decreasing to less than 75,000 feet squared per day in western Dade County. High

  3. Substantial contribution of biomethylation to aquifer arsenic cycling

    NASA Astrophysics Data System (ADS)

    Maguffin, Scott C.; Kirk, Matthew F.; Daigle, Ashley R.; Hinkle, Stephen R.; Jin, Qusheng

    2015-04-01

    Microbes play a prominent role in transforming arsenic to and from immobile forms in aquifers. Much of this cycling involves inorganic forms of arsenic, but microbes can also generate organic forms through methylation, although this process is often considered insignificant in aquifers. Here we identify the presence of dimethylarsinate and other methylated arsenic species in an aquifer hosted in volcaniclastic sedimentary rocks. We find that dimethylarsinate is widespread in the aquifer and its concentration correlates strongly with arsenite concentration. We use laboratory incubation experiments and an aquifer injection test to show that aquifer microbes can produce dimethylarsinate at rates of about 0.1% of total dissolved arsenic per day, comparable to rates of dimethylarsinate production in surface environments. Based on these results, we estimate that globally, biomethylation in aquifers has the potential to transform 100 tons of inorganic arsenic to methylated arsenic species per year, compared with the 420-1,250 tons of inorganic arsenic that undergoes biomethylation in soils. We therefore conclude that biomethylation could contribute significantly to aquifer arsenic cycling. Because biomethylation yields arsine and methylarsines, which are more volatile and prone to diffusion than other arsenic species, we further suggest that biomethylation may serve as a link between surface and subsurface arsenic cycling.

  4. Interaction between the Iska River and the Ljubljansko Barje aquifers

    NASA Astrophysics Data System (ADS)

    Bracic Zeleznik, Branka; Brancelj, Anton

    2010-05-01

    The system of vertically stratified aquifers on the area of the Ljubljansko Barje (i.e. water field Brest) is among the biggest and important drinking water source for central part of Slovenia, including the capital. In the past pollution of groundwater with some specific persistent inorganic pollutants in the lower porous aquifer was detected. To determine origin and intensity of pollution a complex pumping test was performed in autumn 2009 on different wells in the water field Brest. The conceptual model of the Ljubljansko Barje discusses about three rather well separated aquifers. The topmost one is directly fed by the I\\vska rive which flows on the western border of aquifers. To confirm the conceptual model of the system as well as to confirm hydraulic connection between aquifers a intensive pumping experiment was performed in November and December 2009. During the experiment the groundwater level measurement and groundwater quality sampling was carried out. In addition, subsurface fauna was sampled to find similarities between three aquifers. Due to technical problems (damage of animals during pumping) only some representatives of subsurface fauna were collected. Preliminary analyses of fauna confirmed rather rich subterranean fauna with Coppepoda and Amphipoda as dominant groups. At the same time, deep-groundwater aquifer (-50-100 m differs completely from shallow-groundwater aquifer (-7-25 m) which indicates direct connection with the nearby I\\vska River. Detailed analyses of fauna are in progress.

  5. Substantial contribution of biomethylation to aquifer arsenic cycling

    USGS Publications Warehouse

    Maguffin, Scott C.; Kirk, Matthew F.; Daigle, Ashley R.; Hinkle, Stephen R.; Jin, Qusheng

    2015-01-01

    Microbes play a prominent role in transforming arsenic to and from immobile forms in aquifers1. Much of this cycling involves inorganic forms of arsenic2, but microbes can also generate organic forms through methylation3, although this process is often considered insignificant in aquifers4, 5, 6, 7. Here we identify the presence of dimethylarsinate and other methylated arsenic species in an aquifer hosted in volcaniclastic sedimentary rocks. We find that dimethylarsinate is widespread in the aquifer and its concentration correlates strongly with arsenite concentration. We use laboratory incubation experiments and an aquifer injection test to show that aquifer microbes can produce dimethylarsinate at rates of about 0.1% of total dissolved arsenic per day, comparable to rates of dimethylarsinate production in surface environments. Based on these results, we estimate that globally, biomethylation in aquifers has the potential to transform 100 tons of inorganic arsenic to methylated arsenic species per year, compared with the 420–1,250 tons of inorganic arsenic that undergoes biomethylation in soils8. We therefore conclude that biomethylation could contribute significantly to aquifer arsenic cycling. Because biomethylation yields arsine and methylarsines, which are more volatile and prone to diffusion than other arsenic species, we further suggest that biomethylation may serve as a link between surface and subsurface arsenic cycling.

  6. Inquiry and Aquifers.

    ERIC Educational Resources Information Center

    Leuenberger, Ted; Shepardson, Daniel; Harbor, Jon; Bell, Cheryl; Meyer, Jason; Klagges, Hope; Burgess, Willie

    2001-01-01

    Presents inquiry-oriented activities that acquaint students with groundwater sources, movement of water through aquifers, and contamination of groundwater by pollution. In one activity, students use well log data from web-based resources to explore groundwater systems. Provides sample well log data for those not having access to local information.…

  7. Boise Geothermal Aquifer Study

    SciTech Connect

    Not Available

    1990-01-01

    This report is the final product of a detailed review and quantitative evaluation of existing data for the Boise Front Geothermal Aquifer. Upon review of the many publications, and raw data for the Boise geothermal aquifer, it became clear that adequate data only exists for analysis of current and proposed development within a limited area. This region extends approximately 1.5 miles southeast of the State Capitol to 0.5 mile northwest. Though there are geothermal wells located along the Boise Front outside of this area, the lack of production and water level data preclude any detailed discussions and analysis of their relationship to the central resource. As a result, discussion will concentrate on major users such as the Capitol Mall (CM) Boise Geothermal LTD. (BGL), Veterans Administration (VA) and Boise Warm Springs Water District (BWSWD). The objectives of this study are: Define the inter-relationship of the existing wells and/or portions of the geothermal aquifer; evaluate the effects of current and proposed development on the geothermal aquifer; estimate longevity of the geothermal resource; and make recommendations for an on-going monitoring program. 44 refs., 40 figs., 9 tabs.

  8. Effects of reclaimed asphalt pavement on indirect tensile strength test of foamed asphalt mix tested in dry condition

    NASA Astrophysics Data System (ADS)

    Yati Katman, Herda; Rasdan Ibrahim, Mohd; Yazip Matori, Mohd; Norhisham, Shuhairy; Ismail, Norlela

    2013-06-01

    Indirect tensile strength (ITS) test was conducted to analyse strength of the foamed asphalt mixes incorporating reclaimed asphalt pavement. Samples were tested for ITS after cured in the oven at 40°C for 72 hours. This testing condition known as dry condition or unconditioned. Laboratory results show that reclaimed asphalt pavement (RAP) contents insignificantly affect the ITS results. ITS results significantly affected by foamed bitumen contents.

  9. Potential hydrologic effects of ground-water withdrawals from the Dakota Aquifer, southwestern Kansas

    USGS Publications Warehouse

    Watts, K.R.

    1985-01-01

    A study was conducted to evaluate the effects of potential development of the Dakota aquifer on the layered aquifer system above Permian rocks in a 5,000 sq mi area of southwestern Kansas. Transmissivity of the Dakota aquifer, determined from analyses of pumping tests, ranges from 100 to 7,100 sq ft/day. Water in the Dakota aquifer is a calcium bicarbonate type water, similar to water in the High Plains aquifer, in the subcrop area. However, in areas distant from the subcrop, water in the Dakota aquifer is a sodium bicarbonate type water with dissolved solids concentrations in excess of 500 mg/L. Gradual declines in the potentiometric surface of the Dakota aquifer have occurred since the onset of pumpage in the 1960's; however, water levels in some wells have risen during the late 1970's. A digital computer model of 3-D groundwater flow was developed to simulate hydrologic conditions of a five-layer hydrologic system for 1975-82 conditions. The major components of the simulated 1975-82 water budget were well discharge from the High Plains aquifer and loss of ground water from storage in the High Plains aquifer. Although downward leakage from the High Plains aquifer in the study area represented only 18,000 acre-ft of the 1,365 ,000 acre-ft discharged from the High Plains aquifer during 1982 , it was a major source of inflow to the Dakota aquifer. Changes in storage in the Dakota aquifer in the study area during 1982 were about 5,000 acre-ft. A base-line projection was made using 1982 simulated hydraulic heads from the calibrated model and 1982 rates of pumpage from both the High Plains and the Dakota aquifers for comparison with eight additional projection simulations in which maximum pumpage from the Dakota aquifer at the end of the projections ranged from about 78,000 to 294,000 acre-ft/yr. The results from the projections indicate that: (1) pumpage from the Dakota aquifer will have a limited effect on hydraulic heads in the High Plains aquifer, (2) drawdown in

  10. Types of permeability development in limestone aquifers in Britain

    NASA Astrophysics Data System (ADS)

    Worthington, S. R. H.

    2009-04-01

    of karst aquifers types is well demonstrated by examples from England. The Chalk aquifer is an example of the microkarstic type. It has few caves but wells are characterised by high productivity, with a geometric mean transmissivity from pumping tests in 1257 wells of 440 m2/day, with a standard deviation of 0.76 log units. Well logs show that most production is from a few solutionally-enlarged fractures in each well. The Carboniferous Limestone aquifer provides a strong contrast. The geometric mean transmissivity from pumping tests in 59 wells is only 22 m2/day, with a standard deviation of 1.31 log units. Its wide range in well productivity and the presence of large cave streams are both indicators that it is a macrokarstic aquifer. These two contrasting aquifers share a number of common properties. Both have convergent flow to springs and channel networks with rapid flow (typically > 100 m/day). Furthermore, in both cases the matrix of the rock has relatively high porosity and low hydraulic conductivity, whereas the fractures and channels have low porosity and high hydraulic conductivity. Consequently, the flux of water through these aquifers occurs mainly through the channel networks although the matrix provides substantial storage. Other well-documented limestone aquifers in England such as the Magnesian Limestone and Jurassic limestones have transmissivity properties that are intermediate in value between the Chalk and the Carboniferous Limestone and have generally also been considered as being intermediate in karstic characteristics. The above conceptual model that karst aquifer type depends upon the size and frequency of channels provides a good explanation of the range of aquifer properties found in British limestone aquifers.

  11. HUMAN METHAMPHETAMINE PHARMACOKINETICS SIMULATED IN THE RAT: BEHAVIORAL AND NEUROCHEMICAL EFFECTS OF A 72- HOUR BINGE

    PubMed Central

    Kuczenski, Ronald; Segal, David S.; Melega, William P.; Lacan, Goran; McCunney, Stanley J.

    2009-01-01

    Bingeing is one pattern of high dose methamphetamine (METH) abuse which involves continuous drug taking over several days and can result in psychotic behaviors for which the brain pathology remains poorly-defined. A corresponding animal model of this type of METH exposure may provide novel insights into the neurochemical and behavioral sequelae associated with this condition. Accordingly, to simulate the pharmacokinetic profile of a human METH binge exposure in rats we used a computer-controlled, intravenous METH procedure (dynamic infusion) to overcome species differences in METH pharmacokinetics and to replicate the human 12-h plasma METH half-life. Animals were treated over 13 weeks with escalating METH doses, using dynamic infusion, and then exposed to a binge in which drug was administered every 3 h for 72h. Throughout the binge, behavioral effects included unabated intense oral stereotypies in the absence of locomotion and in the absence of sleep. Decrements in regional brain dopamine, norepinephrine and serotonin levels, measured at 1 and 10 h after the last injection of the binge, had, with the exception of caudate-putamen dopamine and frontal cortex serotonin, recovered by 48 h. At 10 h after the last injection of the binge, [3H]ligand binding to dopamine and vesicular monoamine transporters in caudate-putamen were reduced by 35% and 13%, respectively. In a separate METH binge treated cohort, post-binge behavioral alterations were apparent in an attenuated locomotor response to a METH challenge infusion at 24h after the last injection of the binge. Collectively, the changes we characterized during and following a METH binge suggest that for humans under similar exposure conditions, multiple time-dependent neurochemical deficits contribute to their behavioral profiles. PMID:19571794

  12. Analyses and estimates of hydraulic conductivity from slug tests in alluvial aquifer underlying Air Force Plant 4 and Naval Air Station-Joint Reserve Base Carswell Field, Fort Worth, Texas

    USGS Publications Warehouse

    Houston, Natalie A.; Braun, Christopher L.

    2004-01-01

    This report describes the collection, analyses, and distribution of hydraulic-conductivity data obtained from slug tests completed in the alluvial aquifer underlying Air Force Plant 4 and Naval Air Station-Joint Reserve Base Carswell Field, Fort Worth, Texas, during October 2002 and August 2003 and summarizes previously available hydraulic-conductivity data. The U.S. Geological Survey, in cooperation with the U.S. Air Force, completed 30 slug tests in October 2002 and August 2003 to obtain estimates of horizontal hydraulic conductivity to use as initial values in a ground-water-flow model for the site. The tests were done by placing a polyvinyl-chloride slug of known volume beneath the water level in selected wells, removing the slug, and measuring the resulting water-level recovery over time. The water levels were measured with a pressure transducer and recorded with a data logger. Hydraulic-conductivity values were estimated from an analytical relation between the instantaneous displacement of water in a well bore and the resulting rate of head change. Although nearly two-thirds of the tested wells recovered 90 percent of their slug-induced head change in less than 2 minutes, 90-percent recovery times ranged from 3 seconds to 35 minutes. The estimates of hydraulic conductivity range from 0.2 to 200 feet per day. Eighty-three percent of the estimates are between 1 and 100 feet per day.

  13. Ground-water flow directions and estimation of aquifer hydraulic properties in the lower Great Miami River Buried Valley aquifer system, Hamilton Area, Ohio

    USGS Publications Warehouse

    Sheets, Rodney A.; Bossenbroek, Karen E.

    2005-01-01

    The Great Miami River Buried Valley Aquifer System is one of the most productive sources of potable water in the Midwest, yielding as much as 3,000 gallons per minute to wells. Many water-supply wells tapping this aquifer system are purposely placed near rivers to take advantage of induced infiltration from the rivers. The City of Hamilton's North Well Field consists of 10 wells near the Great Miami River, all completed in the lower Great Miami River Buried Valley Aquifer System. A well-drilling program and a multiple-well aquifer test were done to investigate ground-water flow directions and to estimate aquifer hydraulic properties in the lower part of the Great Miami River Buried Valley Aquifer System. Descriptions of lithology from 10 well borings indicate varying amounts and thickness of clay or till, and therefore, varying levels of potential aquifer confinement. Borings also indicate that the aquifer properties can change dramatically over relatively short distances. Grain-size analyses indicate an average bulk hydraulic conductivity value of aquifer materials of 240 feet per day; the geometric mean of hydraulic conductivity values of aquifer material was 89 feet per day. Median grain sizes of aquifer material and clay units were 1.3 millimeters and 0.1 millimeters, respectively. Water levels in the Hamilton North Well Field are affected by stream stage in the Great Miami River and barometric pressure. Bank storage in response to stream stage is evident. Results from a multiple-well aquifer test at the well field indicate, as do the lithologic descriptions, that the aquifer is semiconfined in some areas and unconfined in others. Transmissivity and storage coefficient of the semiconfined part of the aquifer were 50,000 feet squared per day and 5x10-4, respectively. The average hydraulic conductivity (450 feet per day) based on the aquifer test is reasonable for glacial outwash but is higher than calculated from grain-size analyses, implying a scale effect

  14. Hydrogeology and Aquifer Storage and Recovery Performance in the Upper Floridan Aquifer, Southern Florida

    USGS Publications Warehouse

    Reese, Ronald S.; Alvarez-Zarikian, Carlos A.

    2007-01-01

    Well construction, hydraulic well test, ambient water-quality, and cycle test data were inventoried and compiled for 30 aquifer storage and recovery facilities constructed in the Floridan aquifer system in southern Florida. Most of the facilities are operated by local municipalities or counties in coastal areas, but five sites are currently being evaluated as part of the Comprehensive Everglades Restoration Plan. The relative performance of all sites with adequate cycle test data was determined, and compared with four hydrogeologic and design factors that may affect recovery efficiency. Testing or operational cycles include recharge, storage, and recovery periods that each last days or months. Cycle test data calculations were made including the potable water (chloride concentration of less than 250 milligrams per liter) recovery efficiency per cycle, total recovery efficiency per cycle, and cumulative potable water recovery efficiencies for all of the cycles at each site. The potable water recovery efficiency is the percentage of the total amount of potable water recharged for each cycle that is recovered; potable water recovery efficiency calculations (per cycle and cumulative) were the primary measures used to evaluate site performance in this study. Total recovery efficiency, which is the percent recovery at the end of each cycle, however, can be substantially higher and is the performance measure normally used in the operation of water-treatment plants. The Upper Floridan aquifer of the Floridan aquifer system currently is being used, or planned for use, at 29 of the aquifer storage and recovery sites. The Upper Floridan aquifer is continuous throughout southern Florida, and its overlying confinement is generally good; however, the aquifer contains brackish to saline ground water that can greatly affect freshwater storage and recovery due to dispersive mixing within the aquifer. The hydrogeology of the Upper Floridan varies in southern Florida; confinement

  15. Extent and source of saltwater intrusion into the alluvial aquifer near Brinkley, Arkansas, 1984

    USGS Publications Warehouse

    Morris, E.E.; Bush, W.V.

    1986-01-01

    An approximate area of 56 sq mi of the alluvial aquifer just north of Brinkley, Arkansas, has been contaminated by saltwater (chloride concentration > or = 50 mg/L) intruded from underlying aquifers. The contamination was mapped from water quality data for 217 wells. Saltwater problems appear to have spread rapidly in the alluvial aquifer since the late 1940's. Chemical comparisons indicate that the alluvial aquifer was contaminated by water from the Sparta aquifer which in turn was contaminated by the underlying Nacatoch aquifer. The possibility of intrusion into the alluvial aquifer through abandoned oil and gas test wells was investigated but no evidence could be found to support this possibility. Upward movement into the alluvial aquifer from the underlying Sparta aquifer through the thinned or absent Jackson confining unit appears to be the principal reason for saltwater in the alluvial aquifer. Increased withdrawals of water from the alluvial aquifer for irrigation and public supply appear to have contributed to this upward movement. (Author 's abstract)

  16. Aquifers in Cretaceous rocks of the central Coastal Plain of North Carolina

    USGS Publications Warehouse

    Winner, M.D.; Lyke, W.L.

    1989-01-01

    Aquifers in rocks of Cretaceous age are the major source of groundwater for public supplies in the central Coastal Plain. These aquifers consist of sand, gravel, and limestone beds of the Peedee, Black Creek, and the upper and lower Cape Fear aquifers, each separated by a confining unit composed of clay and silt beds. The aquifers and confining units (1) rest upon crystalline basement rocks; (2) dip and thicken to the east-southeast; and (3) are overlain by younger aquifers and confining units in deposits of Quaternary and Tertiary age. The top of the uppermost aquifer, the Peedee, ranges from 122 ft above to 595 ft below sea level. The maximum thickness of all aquifers and confining units in Cretaceous rocks is more than 1,600 ft. Aquifers and confining units were defined and correlated for this report using 125 geophysical logs and accompanying drillers ' logs, water level data, and water quality information regarding chloride concentrations in water. This analysis allowed the construction of seven hydrogeologic cross sections that depict the continuity of all the aquifers and confining units. These cross sections also show water levels and chloride concentrations in water from various test intervals and describe where chloride concentration in water exceeds 250 mg/L within each aquifer. Detailed maps of each Cretaceous aquifer show altitude of its top, thickness, areas of selected sand percentages, transition zones from fresh to saltwater, and the thickness of the confining unit.

  17. Hydraulic properties of the Madison aquifer system in the western Rapid City area, South Dakota

    USGS Publications Warehouse

    Greene, Earl A.

    1993-01-01

    Available information on hydrogeology, data from borehole geophysical logs, and aquifer tests were used to determine the hydraulic properties of the Madison aquifer. From aquifer-test analysis, transmissivity and storage coefficient were determined for the Minnelusa and Madison aquifers, and vertical hydraulic conductivity (Kv') along with specific storage (Ss') for the Minnelusa confining bed. Borehole geophysical well logs were used to determine the thickness and location of the Minnelusa aquifer, the lower Minnelusa confining bed, and the Madison aquifer within the Madison Limestone. Porosity values determined from quantitative analysis of borehole geophysical well logs were used in analyzing the aquifer-test data. The average porosity at the two aquifer-test sites is about 10 percent in the Minnelusa aquifer, 5 percent in the lower Minnelusa confining bed, and 35 percent in the Madison aquifer. The first aquifer test, which was conducted at Rapid City production well #6, produced measured drawdown in the Minnelusa and Madison aquifers. Neuman and Witherspoon's method of determining the hydraulic properties of leaky two-aquifer systems was used to evaluate the aquifer-test data by assuming the fracture and solution-opening network is equivalent to a porous media. Analysis of the aquifer test for the Minnelusa aquifer yielded a transmissivity value of 12,000 feet squared per day and a storage coefficient of 3 x 10-3. The specific storage of the Minnelusa confining bed was 2 x 10-7 per foot, and its vertical hydraulic conductivity was 0.3 foot per day. The transmissivity of the Madison aquifer at this site was 17,000 feet squared per day, and the storage coefficient was 2 x 10-3. The second aquifer test, which was conducted at Rapid City production well #5 (RC-5) produced measured drawdown only in the Madison aquifer. Hantush and Jacob's method of determining the hydraulic properties of leaky confined aquifers with no storage in the confining bed was used to

  18. Multiscale characterization of a heterogeneous aquifer using an ASR operation.

    PubMed

    Pavelic, Paul; Dillon, Peter J; Simmons, Craig T

    2006-01-01

    Heterogeneity in the physical properties of an aquifer can significantly affect the viability of aquifer storage and recovery (ASR) by reducing the recoverable proportion of low-salinity water where the ambient ground water is brackish or saline. This study investigated the relationship between knowledge of heterogeneity and predictions of solute transport and recovery efficiency by combining permeability and ASR-based tracer testing with modeling. Multiscale permeability testing of a sandy limestone aquifer at an ASR trial site showed that small-scale core data give lower-bound estimates of aquifer hydraulic conductivity (K), intermediate-scale downhole flowmeter data offer valuable information on variations in K with depth, and large-scale pumping test data provide an integrated measure of the effective K that is useful to constrain ground water models. Chloride breakthrough and thermal profiling data measured during two cycles of ASR showed that the movement of injected water is predominantly within two stratigraphic layers identified from the flowmeter data. The behavior of the injectant was reasonably well simulated with a four-layer numerical model that required minimal calibration. Verification in the second cycle achieved acceptable results given the model's simplicity. Without accounting for the aquifer's layered structure, high precision could be achieved on either piezometer breakthrough or recovered water quality, but not both. This study demonstrates the merit of an integrated approach to characterizing aquifers targeted for ASR.

  19. Interpretation of earth tide response of three deep, confined aquifers

    SciTech Connect

    Narasimhan, T.N.; Kanehiro, B.Y.; Witherspoon, P.A.

    1984-03-10

    The response of a confined, areally infinite aquifer to external loads imposed by earth tides is examined. Because the gravitational influence of celestial objects occurs over large areas of the earth, the confined aquifer is assumed to respond in an undrained fashion. Since undrained response is controlled by water compressibility, earth tide response can be directly used only to evaluate porous medium compressibility if porosity is known. Moreover, since specific storage S/sub s/ quantifies a drained behavior of the porous medium, one cannot directly estimate S/sub s/from earth tide response. Except for the fact that barometric changes act both on the water surface in the well and on the aquifer as a whole while stress changes associated with earth tides act only in the aquifer, the two phenomena influence the confined aquifer in much the same way. In other words, barometric response contains only as much information on the elastic properties of the aquifer as the earth tide response does. Factors such as well bore storage, aquifer transmissivity, and storage coefficient contribute to time lag and damping of the aquifer response as observed in the well. Analysis shows that the observation of fluid pressure changes alone, without concurrent measurement of external stress changes, is sufficient to interpret uniquely earth tide response. In the present work, change in external stress is estimated from dilatation by assuming a reasonable value for bulk modulus. Earth tide response of geothermal aquifers from Marysville, Montana. East Mesa, California; and Raft River Valley, Idaho, were analyzed, and the ratio of S/sub 3/ to porosity was estimated. Comparison of these estimates with independent pumping tests show reasonable agreement.

  20. Estimating Hydraulic Properties of Coastal Aquifers Using Wave Setup

    NASA Astrophysics Data System (ADS)

    Rotzoll, K.; El-Kadi, A. I.

    2007-12-01

    Wave setup is associated with the momentum transfer of breaking waves to the water column, which results in an elevated mean water table at the coast over several days. Groundwater responses to setup were observed as far as 5 km inland in a coastal aquifer in central Maui, Hawaii. Results showed that setup pulses dominate over barometric pressure effects on low-frequency groundwater fluctuations during times of energetic swell events. Matching peak frequencies in setup and observed head were identified. As is the case with tides, the setup propagation through the aquifer shows exponentially decreasing amplitudes and linearly increasing time lags. Setup was used to estimate a mean aquifer diffusivity of 2.3 x 107 m2/d. The results agree with parameters estimated using aquifer tests and tides. A one-dimensional numerical model verified the results of the estimated parameters. The methodology is expected to be applicable to high-permeability coastal environments, such as volcanic islands and atolls.

  1. Assessing transmissivity from specific capacity in an alluvial aquifer in the middle Venetian plain (NE Italy).

    PubMed

    Fabbri, Paolo; Piccinini, Leonardo

    2013-01-01

    Defining aquifer permeability distribution accurately over large areas is often debated in hydrogeology. The operational efforts to calculate hydraulic conductivity with classical aquifer tests are significant; however, accurate knowledge of permeability areal distribution is fundamental both from a hydrogeological and a modeling standpoint. This paper presents an empirical relationship between the transmissivity (T) and the specific capacity (SC) values obtained from experimental aquifer and well tests. All experimental values were obtained from 50 mm wells in middle Venetian plain artesian gravel aquifers. Many other authors have presented empirical relationships between T and SC, but most are related to fissured/karst aquifers, and only a few concern alluvial porous aquifers. Analysis of the T vs. SC relationship standardized residuals shows that a linear relationship produces statistically significant normal residuals compared with an exponential relationship.

  2. Stochastic modeling of a lava-flow aquifer system

    USGS Publications Warehouse

    Cronkite-Ratcliff, Collin; Phelps, Geoffrey A.

    2014-01-01

    This report describes preliminary three-dimensional geostatistical modeling of a lava-flow aquifer system using a multiple-point geostatistical model. The purpose of this study is to provide a proof-of-concept for this modeling approach. An example of the method is demonstrated using a subset of borehole geologic data and aquifer test data from a portion of the Calico Hills Formation, a lava-flow aquifer system that partially underlies Pahute Mesa, Nevada. Groundwater movement in this aquifer system is assumed to be controlled by the spatial distribution of two geologic units—rhyolite lava flows and zeolitized tuffs. The configuration of subsurface lava flows and tuffs is largely unknown because of limited data. The spatial configuration of the lava flows and tuffs is modeled by using a multiple-point geostatistical simulation algorithm that generates a large number of alternative realizations, each honoring the available geologic data and drawn from a geologic conceptual model of the lava-flow aquifer system as represented by a training image. In order to demonstrate how results from the geostatistical model could be analyzed in terms of available hydrologic data, a numerical simulation of part of an aquifer test was applied to the realizations of the geostatistical model.

  3. Estimating harvested rainwater at greenhouses in south Portugal aquifer Campina de Faro for potential infiltration in Managed Aquifer Recharge.

    NASA Astrophysics Data System (ADS)

    Costa, Luís; Monteiro, José Paulo; Leitão, Teresa; Lobo-Ferreira, João Paulo; Oliveira, Manuel; Martins de Carvalho, José; Martins de Carvalho, Tiago; Agostinho, Rui

    2015-04-01

    The Campina de Faro (CF) aquifer system, located on the south coast of Portugal, is an important source of groundwater, mostly used for agriculture purposes. In some areas, this multi-layered aquifer is contaminated with high concentration of nitrates, possibly arising from excessive usage of fertilizers, reaching to values as high as 300 mg/L. In order to tackle this problem, Managed Aquifer Recharge (MAR) techniques are being applied at demonstration scale to improve groundwater quality through aquifer recharge, in both infiltration basins at the river bed of ephemeral river Rio Seco and existing traditional large diameter wells located in this aquifer. In order to assess the infiltration capacity of the existing infrastructures, in particular infiltration basins and large diameter wells at CF aquifer, infiltration tests were performed, indicating a high infiltration capacity of the existing infrastructures. Concerning the sources of water for recharge, harvested rainwater at greenhouses was identified in CF aquifer area as one of the main potential sources for aquifer recharge, once there is a large surface area occupied by these infrastructures at the demo site. This potential source of water could, in some cases, be redirected to the large diameter wells or to the infiltration basins at the riverbed of Rio Seco. Estimates of rainwater harvested at greenhouses were calculated based on a 32 year average rainfall model and on the location of the greenhouses and their surface areas, the latter based on aerial photograph. Potential estimated annual rainwater intercepted by greenhouses at CF aquifer accounts an average of 1.63 hm3/year. Nonetheless it is unlikely that the totality of this amount can be harvested, collected and redirected to aquifer recharge infrastructures, for several reasons, such as the lack of appropriate greenhouse infrastructures, conduits or a close location between greenhouses and large diameter wells and infiltration basins. Anyway, this

  4. Contamination and restoration of groundwater aquifers.

    PubMed Central

    Piver, W T

    1993-01-01

    Humans are exposed to chemicals in contaminated groundwaters that are used as sources of drinking water. Chemicals contaminate groundwater resources as a result of waste disposal methods for toxic chemicals, overuse of agricultural chemicals, and leakage of chemicals into the subsurface from buried tanks used to hold fluid chemicals and fuels. In the process, both the solid portions of the subsurface and the groundwaters that flow through these porous structures have become contaminated. Restoring these aquifers and minimizing human exposure to the parent chemicals and their degradation products will require the identification of suitable biomarkers of human exposure; better understandings of how exposure can be related to disease outcome; better understandings of mechanisms of transport of pollutants in the heterogeneous structures of the subsurface; and field testing and evaluation of methods proposed to restore and cleanup contaminated aquifers. In this review, progress in these many different but related activities is presented. PMID:8354172

  5. Contamination and restoration of groundwater aquifers.

    PubMed

    Piver, W T

    1993-04-01

    Humans are exposed to chemicals in contaminated groundwaters that are used as sources of drinking water. Chemicals contaminate groundwater resources as a result of waste disposal methods for toxic chemicals, overuse of agricultural chemicals, and leakage of chemicals into the subsurface from buried tanks used to hold fluid chemicals and fuels. In the process, both the solid portions of the subsurface and the groundwaters that flow through these porous structures have become contaminated. Restoring these aquifers and minimizing human exposure to the parent chemicals and their degradation products will require the identification of suitable biomarkers of human exposure; better understandings of how exposure can be related to disease outcome; better understandings of mechanisms of transport of pollutants in the heterogeneous structures of the subsurface; and field testing and evaluation of methods proposed to restore and cleanup contaminated aquifers. In this review, progress in these many different but related activities is presented.

  6. Comparative tracing experiments in a porous aquifer using bacteriophages and fluorescent dye on a test field located at Wilerwald (Switzerland) and simultaneously surveyed in detail on a local scale by radio-magneto-tellury (12 240 kHz)

    NASA Astrophysics Data System (ADS)

    Rossi, P.; de Carvalho-Dill, A.; Müller, I.; Aragno, M.

    1994-04-01

    This article presents an example of a tracing experiment using two bacteriophages, T7 and f1, and a fluorescent dye (naphthionate), in a saturated porous environment. The test field was equipped with an injection borehole and 22 sampling piezometers set in three concentric half-circles. The distribution of permeabilities and the thickness of the aquifer were indirectly determined by Radio-Magneto-Tellury (RMT, 12 240 kHz). The results reveal a good correlation between the distribution of permeabilities obtained by RMT and the breakthrough curves and speed of migration of all three tracers. The restitution levels are far superior (by two to three orders of magnitude) in the more permeable zones, as opposed to those observed in th piezometers situated in less permeable areas. The speed of migration of the biological tracers is much greater than that of the naphthionate. In the most extreme case, the T7 bacteriophage migrated about 3.15 times faster than the chemical solution. These results indicate that bacteriophages are able to travel considerable distances along permeable gravel channels. They may be used as biological tracers and as models for the migration of pathogenic viruses. The simultaneous use of tracing techniques and appropriate geophysical methods leads to a better knowledge of the hydrogeological parameters of the underground terrain. This combination allows for a better interpretation both of the speeds of migration and of the maximal concentrations of the tracers, and thus considerably increases the interpretability of hydrogeological impact studies.

  7. Evaluation of borehole geophysical logging, aquifer-isolation tests, distribution of contaminants, and water-level measurements at the North Penn Area 5 Superfund Site, Bucks and Montgomery counties, Pennsylvania

    USGS Publications Warehouse

    Bird, Philip H.; Conger, Randall W.

    2002-01-01

    Borehole geophysical logging and aquiferisolation (packer) tests were conducted at the North Penn Area 5 Superfund site in Bucks and Montgomery Counties, Pa. Caliper, naturalgamma, single-point-resistance, fluid-temperature, fluid-resistivity, heatpulse-flowmeter, and digital acoustic-televiewer logs and borehole television surveys were collected in 32 new and previously drilled wells that ranged in depth from 68 to 302 feet. Vertical borehole-fluid movement direction and rate were measured with a high-resolution heatpulse flowmeter under nonpumping conditions. The suite of logs was used to locate water-bearing fractures, determine zones of vertical borehole- fluid movement, select depths to set packers, and locate appropriate screen intervals for reconstructing new wells as monitoring wells. Aquifer-isolation tests were conducted in four wells to sample discrete intervals and to determine specific capacities of discrete water-bearing zones. Specific capacities of isolated zones during packer testing ranged from 0.12 to 15.30 gallons per minute per foot. Most fractures identified by borehole geophysical methods as water-producing or water-receiving zones produced water when isolated and pumped. The acoustic-televiewer logs define two basic fracture sets, bedding-plane partings with a mean strike of N. 62? E. and a mean dip of 27? NW., and high-angle fractures with a mean strike of N. 58? E. and a mean dip of 72? SE. Correlation of heatpulse-flowmeter data and acoustic-televiewer logs showed 83 percent of identified water-bearing fractures were high-angle fractures.

  8. SUBSURFACE RESIDENCE TIMES AS AN ALGORITHM FOR AQUIFER SENSITIVITY MAPPING: TESTING THE CONCEPT WITH ANALYTIC ELEMENT GROUND WATER MODELS IN THE CONTENTNEA CREEK BASIN, NORTH CAROLINA, USA

    EPA Science Inventory

    The objective of this research is to test the utility of simple functions of spatially integrated and temporally averaged ground water residence times in shallow "groundwatersheds" with field observations and more detailed computer simulations. The residence time of water in the...

  9. MULTISPECIES REACTIVE TRACER TEST IN A SAND AND GRAVEL AQUIFER, CAPE COD, MASSACHUSETTS: PART 2: TRANSPORT OF CHROMIUM (VI) AND LEAD-, COPPER-, AND ZINC-EDTA TRACERS

    EPA Science Inventory

    This report discusses the transport of a group of reactive tracers over the course of a large-scale, natural gradient tracer test conducted at the USGS Cape Cod Toxic Substances Hydrology Research site, near Falmouth, Massachusetts. The overall objectives of the experiment were ...

  10. 40 CFR 147.2102 - Aquifer exemptions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 24 2013-07-01 2013-07-01 false Aquifer exemptions. 147.2102 Section....2102 Aquifer exemptions. (a) This section identifies any aquifers or their portions exempted in... future exempt other aquifers or their portions, according to applicable procedures, without...

  11. 40 CFR 147.2102 - Aquifer exemptions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 23 2011-07-01 2011-07-01 false Aquifer exemptions. 147.2102 Section....2102 Aquifer exemptions. (a) This section identifies any aquifers or their portions exempted in... future exempt other aquifers or their portions, according to applicable procedures, without...

  12. 40 CFR 147.1952 - Aquifer exemptions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 24 2012-07-01 2012-07-01 false Aquifer exemptions. 147.1952 Section....1952 Aquifer exemptions. (a) This section identifies any aquifers or their portions exempted in... future exempt other aquifers or portions, according to applicable procedures, without codifying...

  13. 40 CFR 147.3003 - Aquifer exemptions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 24 2013-07-01 2013-07-01 false Aquifer exemptions. 147.3003 Section..., Ute Mountain Ute, and All Other New Mexico Tribes § 147.3003 Aquifer exemptions. (a) Aquifer... described in appendix A are hereby exempted. The exempted aquifers are defined by a one-quarter mile...

  14. 40 CFR 147.3003 - Aquifer exemptions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Aquifer exemptions. 147.3003 Section..., Ute Mountain Ute, and All Other New Mexico Tribes § 147.3003 Aquifer exemptions. (a) Aquifer... described in appendix A are hereby exempted. The exempted aquifers are defined by a one-quarter mile...

  15. 40 CFR 147.302 - Aquifer exemptions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 23 2011-07-01 2011-07-01 false Aquifer exemptions. 147.302 Section... Aquifer exemptions. (a) This section identifies any aquifers of their portions exempted in accordance with... other aquifers or portions according to applicable procedures without codifying such exemptions in...

  16. 40 CFR 147.302 - Aquifer exemptions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 23 2014-07-01 2014-07-01 false Aquifer exemptions. 147.302 Section... Aquifer exemptions. (a) This section identifies any aquifers of their portions exempted in accordance with... other aquifers or portions according to applicable procedures without codifying such exemptions in...

  17. 40 CFR 147.2102 - Aquifer exemptions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 23 2014-07-01 2014-07-01 false Aquifer exemptions. 147.2102 Section....2102 Aquifer exemptions. (a) This section identifies any aquifers or their portions exempted in... future exempt other aquifers or their portions, according to applicable procedures, without...

  18. 40 CFR 147.1952 - Aquifer exemptions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 23 2011-07-01 2011-07-01 false Aquifer exemptions. 147.1952 Section....1952 Aquifer exemptions. (a) This section identifies any aquifers or their portions exempted in... future exempt other aquifers or portions, according to applicable procedures, without codifying...

  19. 40 CFR 147.2554 - Aquifer exemptions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Aquifer exemptions. 147.2554 Section... Aquifer exemptions. In accordance with §§ 144.7(b) and 146.4 of this chapter, those portions of aquifers... injection activity. This exemption applies only to the aquifers tabulated below, and includes those...

  20. 40 CFR 147.1952 - Aquifer exemptions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 24 2013-07-01 2013-07-01 false Aquifer exemptions. 147.1952 Section....1952 Aquifer exemptions. (a) This section identifies any aquifers or their portions exempted in... future exempt other aquifers or portions, according to applicable procedures, without codifying...

  1. 40 CFR 147.1652 - Aquifer exemptions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Aquifer exemptions. 147.1652 Section... Aquifer exemptions. (a) This section identifies any aquifer or their portions exempted in accordance with... other aquifers or portions, according to applicable procedures, without codifying such exemptions...

  2. 40 CFR 147.1652 - Aquifer exemptions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 23 2011-07-01 2011-07-01 false Aquifer exemptions. 147.1652 Section... Aquifer exemptions. (a) This section identifies any aquifer or their portions exempted in accordance with... other aquifers or portions, according to applicable procedures, without codifying such exemptions...

  3. 40 CFR 147.302 - Aquifer exemptions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 24 2013-07-01 2013-07-01 false Aquifer exemptions. 147.302 Section... Aquifer exemptions. (a) This section identifies any aquifers of their portions exempted in accordance with... other aquifers or portions according to applicable procedures without codifying such exemptions in...

  4. 40 CFR 147.102 - Aquifer exemptions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 23 2011-07-01 2011-07-01 false Aquifer exemptions. 147.102 Section... Aquifer exemptions. (a) This section identifies any aquifers or their portions exempted in accordance with... other aquifers or portions, according to applicable procedures, without codifying such exemptions...

  5. 40 CFR 147.3003 - Aquifer exemptions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 23 2011-07-01 2011-07-01 false Aquifer exemptions. 147.3003 Section..., Ute Mountain Ute, and All Other New Mexico Tribes § 147.3003 Aquifer exemptions. (a) Aquifer... described in appendix A are hereby exempted. The exempted aquifers are defined by a one-quarter mile...

  6. 40 CFR 147.2102 - Aquifer exemptions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 24 2012-07-01 2012-07-01 false Aquifer exemptions. 147.2102 Section....2102 Aquifer exemptions. (a) This section identifies any aquifers or their portions exempted in... future exempt other aquifers or their portions, according to applicable procedures, without...

  7. 40 CFR 147.302 - Aquifer exemptions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Aquifer exemptions. 147.302 Section... Aquifer exemptions. (a) This section identifies any aquifers of their portions exempted in accordance with... other aquifers or portions according to applicable procedures without codifying such exemptions in...

  8. 40 CFR 147.1952 - Aquifer exemptions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 23 2014-07-01 2014-07-01 false Aquifer exemptions. 147.1952 Section....1952 Aquifer exemptions. (a) This section identifies any aquifers or their portions exempted in... future exempt other aquifers or portions, according to applicable procedures, without codifying...

  9. 40 CFR 147.2554 - Aquifer exemptions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 23 2011-07-01 2011-07-01 false Aquifer exemptions. 147.2554 Section... Aquifer exemptions. In accordance with §§ 144.7(b) and 146.4 of this chapter, those portions of aquifers... injection activity. This exemption applies only to the aquifers tabulated below, and includes those...

  10. 40 CFR 147.3003 - Aquifer exemptions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 23 2014-07-01 2014-07-01 false Aquifer exemptions. 147.3003 Section..., Ute Mountain Ute, and All Other New Mexico Tribes § 147.3003 Aquifer exemptions. (a) Aquifer... described in appendix A are hereby exempted. The exempted aquifers are defined by a one-quarter mile...

  11. 40 CFR 147.102 - Aquifer exemptions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 24 2013-07-01 2013-07-01 false Aquifer exemptions. 147.102 Section... Aquifer exemptions. (a) This section identifies any aquifers or their portions exempted in accordance with... other aquifers or portions, according to applicable procedures, without codifying such exemptions...

  12. 40 CFR 147.2102 - Aquifer exemptions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Aquifer exemptions. 147.2102 Section....2102 Aquifer exemptions. (a) This section identifies any aquifers or their portions exempted in... future exempt other aquifers or their portions, according to applicable procedures, without...

  13. 40 CFR 147.1952 - Aquifer exemptions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Aquifer exemptions. 147.1952 Section....1952 Aquifer exemptions. (a) This section identifies any aquifers or their portions exempted in... future exempt other aquifers or portions, according to applicable procedures, without codifying...

  14. 40 CFR 147.1652 - Aquifer exemptions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 23 2014-07-01 2014-07-01 false Aquifer exemptions. 147.1652 Section... Aquifer exemptions. (a) This section identifies any aquifer or their portions exempted in accordance with... other aquifers or portions, according to applicable procedures, without codifying such exemptions...

  15. 40 CFR 147.2554 - Aquifer exemptions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 23 2014-07-01 2014-07-01 false Aquifer exemptions. 147.2554 Section... Aquifer exemptions. In accordance with §§ 144.7(b) and 146.4 of this chapter, those portions of aquifers... injection activity. This exemption applies only to the aquifers tabulated below, and includes those...

  16. 40 CFR 147.1652 - Aquifer exemptions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 24 2012-07-01 2012-07-01 false Aquifer exemptions. 147.1652 Section... Aquifer exemptions. (a) This section identifies any aquifer or their portions exempted in accordance with... other aquifers or portions, according to applicable procedures, without codifying such exemptions...

  17. 40 CFR 147.2554 - Aquifer exemptions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 24 2012-07-01 2012-07-01 false Aquifer exemptions. 147.2554 Section... Aquifer exemptions. In accordance with §§ 144.7(b) and 146.4 of this chapter, those portions of aquifers... injection activity. This exemption applies only to the aquifers tabulated below, and includes those...

  18. 40 CFR 147.1652 - Aquifer exemptions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 24 2013-07-01 2013-07-01 false Aquifer exemptions. 147.1652 Section... Aquifer exemptions. (a) This section identifies any aquifer or their portions exempted in accordance with... other aquifers or portions, according to applicable procedures, without codifying such exemptions...

  19. 40 CFR 147.302 - Aquifer exemptions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 24 2012-07-01 2012-07-01 false Aquifer exemptions. 147.302 Section... Aquifer exemptions. (a) This section identifies any aquifers of their portions exempted in accordance with... other aquifers or portions according to applicable procedures without codifying such exemptions in...

  20. 40 CFR 147.2554 - Aquifer exemptions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 24 2013-07-01 2013-07-01 false Aquifer exemptions. 147.2554 Section... Aquifer exemptions. In accordance with §§ 144.7(b) and 146.4 of this chapter, those portions of aquifers... injection activity. This exemption applies only to the aquifers tabulated below, and includes those...

  1. 40 CFR 147.102 - Aquifer exemptions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Aquifer exemptions. 147.102 Section... Aquifer exemptions. (a) This section identifies any aquifers or their portions exempted in accordance with... other aquifers or portions, according to applicable procedures, without codifying such exemptions...

  2. 40 CFR 147.102 - Aquifer exemptions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 23 2014-07-01 2014-07-01 false Aquifer exemptions. 147.102 Section... Aquifer exemptions. (a) This section identifies any aquifers or their portions exempted in accordance with... other aquifers or portions, according to applicable procedures, without codifying such exemptions...

  3. 40 CFR 147.3003 - Aquifer exemptions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 24 2012-07-01 2012-07-01 false Aquifer exemptions. 147.3003 Section..., Ute Mountain Ute, and All Other New Mexico Tribes § 147.3003 Aquifer exemptions. (a) Aquifer... described in appendix A are hereby exempted. The exempted aquifers are defined by a one-quarter mile...

  4. 40 CFR 147.102 - Aquifer exemptions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 24 2012-07-01 2012-07-01 false Aquifer exemptions. 147.102 Section... Aquifer exemptions. (a) This section identifies any aquifers or their portions exempted in accordance with... other aquifers or portions, according to applicable procedures, without codifying such exemptions...

  5. Studies and projections of hydraulic conductivity of Devonian Plavinu and Daugava carbonate aquifers in Latvia

    NASA Astrophysics Data System (ADS)

    Perkone, E.; Delina, A.; Saks, T.; Raga, B.; Jātnieks, J.; Klints, I.; Popovs, K.; Babre, A.; Bikše, J.; Kalvāns, A.; Retike, I.; Ukass, J.

    2012-04-01

    Carbonate aquifers show a very wide range of hydrogeological characteristics. Carbonate rock hydrogeology display two extremes: on one hand hydrogeological properties of the carbonates are governed by the pathways of the preferential groundwater flow typical in karstic regions, on the other - some carbonate aquifers behave almost like a homogeneous, isotropic, porous medium. Most lie between these extremes, but these case variations complicates the study of carbonate aquifer properties. In this study the results of the hydraulic conductivity in carbonate aquifers measurements, hydraulic conductivity correlation between sediments lithology and the aquifer surface depth and fractures research is presented. Upper Devonian Frasnian stage Pļaviņu and Daugava carbonate aquifers in the Latvian part of the Baltic basin is considered. The aim of this research is to elaborate characteristic hydraulic conductivity values for each aquifer based on existing data of the pumping test results and other aquifer properties. Pļaviņu and Daugava carbonate aquifers mainly consist of jointed dolomite with intermediate layers of dolomitic marlstone, limestone, clays and gypsum. These aquifers are prevalent in most of the study area, except Northern and South - Eastern parts of the territory. In geological structure Daugava aquifer lies above Pļaviņu aquifer. Daugava aquifer depth changes from 10 - 20 and even less meters in Eastern part to 250 - 300 m in South - West part of study area, but thickness varies from few meters to 30 m. Pļaviņu aquifer surface depth varies from 20 - 30 m, but in uplands surface depth reaches more than 120 m, in Eastern part to more than 300 m in South - West part of study area. Aquifer average thickness varies from 20 - 40 m, but in areas with buried valleys thickness can be less than 10 meters. Outcrops of these sediments are occurring in banks of largest rivers and in some areas aquifers are karstified. In studies of the carbonate aquifers it is

  6. Effects of clay dispersion on aquifer storage and recovery in coastal aquifers

    USGS Publications Warehouse

    Konikow, L.F.; August, L.L.; Voss, C.I.

    2001-01-01

    Cyclic injection, storage, and withdrawal of freshwater in brackish aquifers is a form of aquifer storage and recovery (ASR) that can beneficially supplement water supplies in coastal areas. A 1970s field experiment in Norfolk, Virginia, showed that clay dispersion in the unconsolidated sedimentary aquifer occurred because of cation exchange on clay minerals as freshwater displaced brackish formation water. Migration of interstitial clay particles clogged pores, reduced permeability, and decreased recovery efficiency, but a calcium preflush was found to reduce clay dispersion and lead to a higher recovery efficiency. Column experiments were performed in this study to quantify the relations between permeability changes and clay mineralogy, clay content, and initial water salinity. The results of these experiments indicate that dispersion of montmorillonite clay is a primary contributor to formation damage. The reduction in permeability by clay dispersion may be expressed as a linear function of chloride content. Incorporating these simple functions into a radial, cross-sectional, variable-density, ground-water flow and transport model yielded a satisfactory simulation of the Norfolk field test - and represented an improvement over the model that ignored changes in permeability. This type of model offers a useful planning and design tool for ASR operations in coastal clastic aquifer systems.

  7. Further Analysis of Borehole Flow-Meters in Granular Aquifers

    NASA Astrophysics Data System (ADS)

    Crisman, S. A.; Molz, F. J.

    2001-12-01

    The borehole flow-meter has emerged as a powerful tool for identifying conductive fractures in fractured rock aquifers and intermediate-scale heterogeneities in hydraulic conductivity (K) distributions in granular aquifers [Hess, Canadian Geotechnical J., 23, 69, 1986; Molz et al., Water Resour. Res., 25, 1677, 1989]. A common analysis technique applied to flow-meter data [Molz and Young, The Log Analyst, 3, 13, 1993] is based on a numerical study of transient flow in multi-layered aquifers by Javandel and Witherspoon [Water Resour. Res., 5, 856, 1969], the purpose of which was to determine the time required for flow to a well to become horizontal in the near vicinity of the well bore and proportional to the hydraulic conductivity distribution. Ultimately, the criterion that resulted was questioned by Ruud and Kabala [Water Resour. Res., 32, 845, 1996] and shown to be potentially lacking in some respects. The Javandel and Witherspoon study did not consider the effect of specific storage (Ss) changes fully, while the Ruud and Kabala study was limited to aquifers of 2 and 5 layers. Most aquifers are not strictly layered, and there is a significant degree of correlation between K and Ss. Therefore, the present study extends the powerful analysis technique of Javandel and Witherspoon to many layered aquifers with realistic K and Ss values. Governing equations are non-dimensionalized in such a way that dimensionless drawdown versus dimensionless time curves at different positions in the aquifer approach the unique Theis curve when flow becomes horizontal in the near-well vicinity and proportional to the corresponding K distribution in the vertical. From these results, practical criteria are derived for performing borehole flow-meter tests in granular aquifers.

  8. Saline aquifer mapping project in the southeastern United States

    USGS Publications Warehouse

    Williams, Lester J.; Spechler, Rick M.

    2011-01-01

    In 2009, the U.S. Geological Survey initiated a study of saline aquifers in the southeastern United States to evaluate the potential use of brackish or saline water from the deeper portions of the Floridan aquifer system and the underlying Coastal Plain aquifer system (Fig. 1). The objective of this study is to improve the overall understanding of the available saline water resources for potential future development. Specific tasks are to (1) develop a digital georeferenced database of borehole geophysical data to enable analysis and characterization of saline aquifers (see locations in Fig. 1), (2) identify and map the regional extent of saline aquifer systems and describe the thickness and character of hydrologic units that compose these systems, and (3) delineate salinity variations at key well sites and along section lines to provide a regional depiction of the freshwater-saltwater interfaces. Electrical resistivity and induction logs, coupled with a variety of different porosity logs (sonic, density, and neutron), are the primary types of borehole geophysical logs being used to estimate the water quality in brackish and saline formations. The results from the geophysical log calculations are being compared to available water-quality data obtained from water wells and from drill-stem water samples collected in test wells. Overall, the saline aquifer mapping project is helping to improve the understanding of saline water resources in the area. These aquifers may be sources of large quantities of water that could be treated by using reverse osmosis or similar technologies, or they could be used for aquifer storage and recovery systems.

  9. Diffuse atrazine pollution in German aquifers.

    PubMed

    Tappe, Wolfgang; Groeneweg, Joost; Jantsch, Barbara

    2002-01-01

    Until its prohibition in Germany in 1991, atrazine was the most frequently applied herbicide in maize cultivation. Moreover, it was used in orchards and vineyards and as a total herbicide on non-cultivated grounds (railways, factory grounds). Later on, atrazine was substituted mainly by terbutylazine. Terbutylazine and terbutryn are the only s-triazines presently permitted in Germany. Nevertheless, atrazine and its metabolite desethylatrazine are by far the most abundant herbicides detected in near surface groundwater. This might be due to wash-outs from the pools of atrazine and its metabolites from the soil into the groundwater or continuing illegal applications. Samples taken from maize fields in 1994 showed that 6.2% of 471 fields tested were treated with atrazine despite the prohibition of its use. Nevertheless, the overall trend is in fact a slow decrease in atrazine concentrations where it is detected in groundwater and, simultaneously often a slight increase in desethylatrazine concentrations. But this is not the case for all sampling points, and increasing concentrations in several aquifers are observed as well. Factors governing the adsorption, degradation, persistence and the possible transfer into the aquifer and the current situation concerning atrazine occurrence in German aquifers will be discussed.

  10. Evaluating Transmissivity Estimates from Well Hydrographs in Karst Aquifers

    SciTech Connect

    Powers, J.g.; Shevenell, l

    1999-07-01

    Hydrograph recessions from rainfall events have previously been analyzed for discharge at springs and streams; however, relatively little quantitative research has been conducted with regard to hydrograph analysis of recessions from monitoring wells screened in karst aquifers. In previous work a quantitative hydrography analysis technique has been proposed born which matrix transmissivity (i.e., transmissivity of intergranular porosity) and specific yields of matrix, fracture, and conduit components of the aquifer may be determined from well hydrography. The technique has yielded realistic results at three sites tested by the authors thus far (Y-12, Oak Ridge, TN; Crane, IN, and Ft. Campbell, KY). Observed field data, as well as theoretical considerations, show that karst well hydrography are valid indicators of hydraulic properties of the associated karst aquifers. Results show matrix transmissivity (T) values to be in good agreement with values calculated using more traditional parameter estimation techniques such as aquifer pumping tests and slug tests in matrix dominated wells. While the hydrograph analysis technique shows promise for obtaining reliable estimates of karst aquifer T with a simple, relatively inexpensive and passive method, the utility of the technique is limited in its application depending on site-specific hydrologic conditions, which include shallow, submerged conduit systems located in areas with sufficient rainfall for water levels to respond to precipitation events.

  11. Hydrogeology of a Transboundary Sandstone Aquifer, Quebec - New York

    NASA Astrophysics Data System (ADS)

    Nastev, M.; Lamontagne, C.; Morin, R.; Williams, J.; Lavigne, M.; Croteau, A.; Tremblay, T.; Godin, R.; Dagenais, M.; Rouleau, A.

    2005-12-01

    The Potsdam sandstone aquifer of Cambrian age straddles southern Quebec and northern New York in a region known for its abundant and good quality groundwater, a resource that recently has been coveted by several bottling companies. The potential conflicts and concerns of the mainly rural and groundwater dependent population about the possible overuse of this resource has led the Quebec Ministry of Environment, Geological Survey of Canada and the U. S. Geological Survey to jointly carry out a transboundary hydrogeological study of the Potsdam sandstone aquifer. The Potsdam sandstone aquifer consists of a lower unit of arkose and conglomerate and an upper unit of well-cemented quartz arenite. The thickness of the regional aquifer ranges from nil at the base of Adirondacks to more than 500 m near the St. Lawrence River. Glacial till, littoral sand and gravel, and marine silt and clay discontinuously overlie the aquifer. The aquifer's water budget is characterized by low rates of surface runoff and high rates of infiltration and sub-surface runoff. Major recharge areas are present at higher altitudes near and to the south of the border. Strong downward hydraulic gradients in these areas result in cascading water and water-level depths of more than 30 m in deep wells. Bedding in the Potsdam sandstone is gently dipping with fractures along sub-horizontal bedding planes forming major flow conduits. Bedrock folds and faults, mainly developed by east-west compression during the Appalachian orogenies, locally complicates aquifer geometry and groundwater flow. Hydraulic tests (pump, slug, flowmeter and straddle packer) indicate similar horizontal transmissivities in the lower and upper aquifer units. However, differences in lithology and structure of the aquifer units impose some apparent differences in hydraulic properties and groundwater flow patterns. In the lower unit, regional flow appears to be sustained by a limited number of laterally extensive bedding-plane fractures

  12. Aquifer thermal energy storage program

    NASA Technical Reports Server (NTRS)

    Fox, K.

    1980-01-01

    The purpose of the Aquifer Thermal Energy Storage Demonstration Program is to stimulate the interest of industry by demonstrating the feasibility of using a geological formation for seasonal thermal energy storage, thereby, reducing crude oil consumption, minimizing thermal pollution, and significantly reducing utility capital investments required to account for peak power requirements. This purpose will be served if several diverse projects can be operated which will demonstrate the technical, economic, environmental, and institutional feasibility of aquifer thermal energy storage systems.

  13. Stochastic analysis of the hydraulic conductivity estimated for a heterogeneous aquifer via numerical modelling

    NASA Astrophysics Data System (ADS)

    Lu, C.; Zhang, Y.; Shu, L.; Chen, X.; Chen, S.; Li, S.; Wang, G.; Li, J.

    2015-05-01

    The paper aims to evaluate the impacts of the average hydraulic conductivity of the heterogeneous aquifer on the estimated hydraulic conductivity using the observations from pumping tests. The results of aquifer tests conducted at a karst aquifer are first introduced. A MODFLOW groundwater flow model was developed to perform numerical pumping tests, and the heterogeneous hydraulic conductivity (K) field was generated using the Monte Carlo method. The K was estimated by the Theis solution for an unconfined aquifer. The effective hydraulic conductivity (Ke) was calculated to represent the hydraulic conductivity of a heterogeneous aquifer. The results of numerical simulations demonstrate that Ke increase with the mean of hydraulic conductivity (EK), and decrease with the coefficient of variation of the hydraulic conductivity (Cv). The impact of spatial variability of K on the estimated Ke at two observation wells with smaller EK is less significant compared to the cases with larger EK.

  14. Preliminary evaluation of a geothermal aquifer in Southern England

    SciTech Connect

    Burgess, W.G.

    1986-11-01

    The preliminary evaluation of the first direct-use (low enthalpy) geothermal well in the United Kingdom included core analysis, geophysical logging, and drill-stem testing. The effective aquifer is restricted to a few relatively thin loosely cemented bands in the Triassic sandstones at a depth of approximately 1660 m. With an aquifer temperature of at least 67/sup 0/C the initial assessment of transmissivity, 18 m/sup 2//day, suggested that a thermal yield of approximately 2.5 MW would be obtainable. The results are in reasonable agreement with those of a subsequent long-term production test.

  15. In Brief: Assessing carbonate aquifers

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2009-07-01

    An assessment of water quality in 12 carbonate aquifers, mostly in the eastern and central United States, found that while water quality in the aquifers was highly variable, most of the samples met drinking water standards. The study, “Factors affecting water quality in selected carbonate aquifers in the United States, 1993-2005,” was released by the U.S. Geological Survey (USGS) on 26 June. According to the study, carbonate aquifers provide about 20% of the groundwater used as drinking water in the United States. The study, which included sample results for 151 chemical constituents or physical properties in 1042 wells and springs across 20 states, found that contaminants “were most often detected at concentrations less than human-health benchmarks except for nitrate.” The study also indicated that “the occurrence of anthropogenic contaminants was related to contaminant sources but also was affected by degree of aquifer confinement, ground-water age, and redox status. Areas with higher amounts of agricultural or urban land in unconfined aquifers were the most likely to have elevated concentrations of anthropogenic contaminants.”

  16. Characterizing Aquifer Heterogeneity Using Bacterial and Bacteriophage Tracers.

    PubMed

    Flynn, Raymond M; Mallèn, German; Engel, Marion; Ahmed, Ashraf; Rossi, Pierre

    2015-09-01

    Gravel aquifers act as important potable water sources in central western Europe, yet they are subject to numerous contamination pressures. Compositional and textural heterogeneity makes protection zone delineation around groundwater supplies in these units challenging; artificial tracer testing aids characterization. This paper reappraises previous tracer test results in light of new geological and microbiological data. Comparative passive gradient testing, using a fluorescent solute (Uranine), virus (H40/1 bacteriophage), and comparably sized bacterial tracers and , was used to investigate a calcareous gravel aquifer's ability to remove microbiological contaminants at a test site near Munich, Germany. Test results revealed relative recoveries could exceed those of H40/1 at monitoring wells, 10 m and 20 m from an injection well, by almost four times; recoveries varied by a factor of up to three between wells. Application of filtration theory suggested greater attenuation of H40/1 relative to similarly charged occurred due to differences in microorganism size, while estimated collision efficiencies appeared comparable. By contrast, more positively charged experienced greater attenuation at one monitoring point, while lower attenuation rates at the second location indicated the influence of geochemical heterogeneity. Test findings proved consistent with observations from nearby fresh outcrops that suggested thin open framework gravel beds dominated mass transport in the aquifer, while discrete intervals containing stained clasts reflect localized geochemical heterogeneity. Study results highlight the utility of reconciling outcrop observations with artificial tracer test responses, using microbiological tracers with well-defined properties, to characterize aquifer heterogeneity.

  17. Characterizing Aquifer Heterogeneity Using Bacterial and Bacteriophage Tracers.

    PubMed

    Flynn, Raymond M; Mallèn, German; Engel, Marion; Ahmed, Ashraf; Rossi, Pierre

    2015-09-01

    Gravel aquifers act as important potable water sources in central western Europe, yet they are subject to numerous contamination pressures. Compositional and textural heterogeneity makes protection zone delineation around groundwater supplies in these units challenging; artificial tracer testing aids characterization. This paper reappraises previous tracer test results in light of new geological and microbiological data. Comparative passive gradient testing, using a fluorescent solute (Uranine), virus (H40/1 bacteriophage), and comparably sized bacterial tracers and , was used to investigate a calcareous gravel aquifer's ability to remove microbiological contaminants at a test site near Munich, Germany. Test results revealed relative recoveries could exceed those of H40/1 at monitoring wells, 10 m and 20 m from an injection well, by almost four times; recoveries varied by a factor of up to three between wells. Application of filtration theory suggested greater attenuation of H40/1 relative to similarly charged occurred due to differences in microorganism size, while estimated collision efficiencies appeared comparable. By contrast, more positively charged experienced greater attenuation at one monitoring point, while lower attenuation rates at the second location indicated the influence of geochemical heterogeneity. Test findings proved consistent with observations from nearby fresh outcrops that suggested thin open framework gravel beds dominated mass transport in the aquifer, while discrete intervals containing stained clasts reflect localized geochemical heterogeneity. Study results highlight the utility of reconciling outcrop observations with artificial tracer test responses, using microbiological tracers with well-defined properties, to characterize aquifer heterogeneity. PMID:26436262

  18. Hydrologic analysis of data for the Lost Lake Aquifer Zone of the Steel Pond Aquifer at recovery well RWM-16

    SciTech Connect

    Wells, D.G.; Cook, J.W.; Hiergesell, R.A.

    1993-04-01

    This report presents the results of an analysis of data obtained from a large-scale, multiple-well aquifer test of the sandy unit referred to as the Lost Lake Aquifer Zone of the Steed Pond Aquifer in an area just south of the A and M Areas. Pumping was conducted at recovery well RWM-16, which is located near the MSB-40 well cluster, approximately 4000 feet south of the M-Area Basin. RWM-16 is located in the lower left portion of Figure 1, which also illustrates the general relationship of the testing site to the A and M Areas and other monitor wells. The data generated from testing RWM-16 was used to calculate estimates of transmissivity and storage for the aquifer system within which RWM-16 is screened. These parameters are related to hydraulic conductivity and storativity of the aquifer system by the vertical thickness of the unit. The leakage coefficient for the overlying confining unit is also estimated. This information is needed to refine conceptual understanding of the groundwater flow system beneath the A and M Areas. The refined conceptual model will more adequately describe the pattern of groundwater flow, and will contribute to updating the {open_quotes}Zone of Capture{close_quotes} model that has been used in the initial phases of designing a groundwater remediation system in the A and M Areas.

  19. Geohydrology of the Flints Pond Aquifer, Hollis, New Hampshire

    USGS Publications Warehouse

    Ayotte, Joseph D.; Dorgan, Tracy H.

    1995-01-01

    Flints pond has been subjected to accelerated eutrophication as a result of watershed development (building of new homes and conversion of summer cottages into permanent homes) since the 1930's. Ground-water flow is the primary recharge and discharge mechanism for Flints Pond. The saturated thickness, transmissive properties, and altitude of the water table were determined by use of surface geophysics, test drilling, and aquifer-test data. Information on the geohydrology of the adjacent Flints Pond aquifer can be used in developing a water and nutrient budget for the pond-aquifer system. Ground-penetrating-radar surveys were done over more than 4 miles of the study area and on Flints Pond. Three distinct reflection signatures were commonly identifiable on the radar profiles: (1) thin, relatively flat-lying, continuous reflectors that represent fine-grained lacustrine sediment; (2) subparallel to hummocky and chaotic, coarse-grained reflectors that possibly represent coarse-grained ice-contact deposits or deltaic sediments in a lacustrine environment; and (3) sharply diffracted, fine-grained, chaotic reflectors that represent till and (or) till over bedrock. The saturated thickness of the aquifer exceeds 90 feet in the northern end of the study area and averages 30 to 50 feet in the southern and eastern parts. The saturated thickness of the western part is generally less than 10 feet. Test borings were completed at 19 sites and 13 wells (6 of which were nested pairs) were installed in various lithologic units. A water-table map, constructed from data collected in November 1994, represents average water-table conditions in the aquifer. Horizontal hydraulic conductivities calculated from single-well aquifer test data for stratified drift range from 2.8 to 226 feet per day. Hydraulic conductivities were quantitatively correlated with the reflector signatures produced with ground-penetrating radar so that transmissivities could be inferred for areas where well data were

  20. Groundwater quality of the Gulf Coast aquifer system, Houston, Texas, 2007-08

    USGS Publications Warehouse

    Oden, Jeannette H.; Oden, Timothy D.; Szabo, Zoltan

    2010-01-01

    In the summers of 2007 and 2008, the U.S. Geological Survey (USGS), in cooperation with the City of Houston, Texas, completed an initial reconnaissance-level survey of naturally occurring contaminants (arsenic, other selected trace elements, and radionuclides) in water from municipal supply wells in the Houston area. The purpose of this reconnaissance-level survey was to characterize source-water quality prior to drinking water treatment. Water-quality samples were collected from 28 municipal supply wells in the Houston area completed in the Evangeline aquifer, Chicot aquifer, or both. This initial survey is part of ongoing research to determine concentrations, spatial extent, and associated geochemical conditions that might be conducive for mobility and transport of these constituents in the Gulf Coast aquifer system in the Houston area. Samples were analyzed for major ions (calcium, magnesium, potassium, sodium, bromide, chloride, fluoride, silica, and sulfate), selected chemically related properties (residue on evaporation [dissolved solids] and chemical oxygen demand), dissolved organic carbon, arsenic species (arsenate [As(V)], arsenite [As(III)], dimethylarsinate [DMA], and monomethylarsonate [MMA]), other trace elements (aluminum, antimony, arsenic, barium, beryllium, boron, cadmium, chromium, cobalt, copper, iron, lead, lithium, manganese, molybdenum, nickel, selenium, silver, strontium, thallium, vanadium, and zinc), and selected radionuclides (gross alpha- and beta-particle activity [at 72 hours and 30 days], carbon-14, radium isotopes [radium-226 and radium-228], radon-222, tritium, and uranium). Field measurements were made of selected physicochemical (relating to both physical and chemical) properties (oxidation-reduction potential, turbidity, dissolved oxygen concentration, pH, specific conductance, water temperature, and alkalinity) and unfiltered sulfides. Dissolved organic carbon and chemical oxygen demand are presented but not discussed in the

  1. Characterisation of a DNAPL source zone in a porous aquifer using the Partitioning Interwell Tracer Test and an inverse modelling approach.

    PubMed

    Dridi, Lotfi; Pollet, Ingrid; Razakarisoa, Olivier; Schäfer, Gerhard

    2009-06-26

    In this paper, we discuss the results of a Partitioning Interwell Tracer Test (PITT) performed in a large scale experiment with a well-defined TCE spill, and present a novel combined analytical-numerical inverse modelling approach using measured concentration profiles within a TCE plume to predict the distribution of the DNAPL in a virtual vertical plane of the source. The proposed inverse modelling approach assumes local thermodynamic equilibrium of the distribution of TCE between the NAPL phase and the aqueous phase and no decay or sorption of the dissolved TCE concentrations downstream of the spill area. The analytical part of the inverse modelling approach contains two steps. As a first step, the location of the contaminant in a virtual vertical plane of a porous medium is fixed by using measured concentration profiles and considering the dissolution of the organic phase under equilibrium conditions. In the second step, the volume of contaminant entrapped in the source cells is estimated. A multiphase advective-dispersive transport model is used in the final step to adjust the volumes quantified in the second step. The predictions are highly dependent on the quantity and quality of the data in space and time. From the PITT-breakthrough curves measured at the pumping well, a mean TCE saturation in the sweep zone of 0.0004 was derived, which is very low compared to that determined at the local scale. In a second analysis, tracer breakthrough curves available at measuring points placed closely downstream and upstream of the presumed source zone, were used to explain why the globally obtained DNAPL saturation was very low compared to the "real", locally evaluated TCE saturations in the source zone. This was principally caused by the overall travel time compared to the short travel time of the tracers in the source zone. Another reason is that due to bypassing, only part of the volume of tracer injected had been in contact and had eventually interacted with the

  2. Groundwater Exploration in Freshwater/Saline Layered Aquifers - Southern Bangladesh.

    NASA Astrophysics Data System (ADS)

    McKelvey, P. A.; Rahman, M.

    2001-05-01

    drilling techniques. In most cases, a hand drilled borehole could be drilled to 300 m within ten days, in the unconsolidated sands and clays. A hand operated downhole geophysical unit was then used to run a resistivity log to locate freshwater sands. Where thick freshwater units were identified, the main production rig was mobilised to construct high capacity wells. In total, 33 production wells have been installed in the nine towns over Southern Bangladesh. Pumping tests were undertaken to establish well and aquifer properties. These data have been used to establish strict operating rules for the wellfields to minimise the risks of saline intrusion.

  3. Interpretation of borehole geophysical logs, aquifer-isolation tests, and water quality, supply wells 1 and 2, Willow Grove Naval Air Station/Joint Reserve Base, Horsham Township, Montgomery County, Pennsylvania

    USGS Publications Warehouse

    Sloto, Ronald A.; Goode, Daniel J.; Frasch, Steven M.

    2002-01-01

    Ground water pumped from supply wells 1 and 2 on the Willow Grove Naval Air Station/Joint Reserve Base (NAS/JRB) provides water for use at the base, including potable water for drinking. The supply wells have been contaminated by volatile organic compounds (VOC?s), particularly trichloroethylene (TCE) and tetrachloroethylene (PCE), and the water is treated to remove the VOC?s. The Willow Grove NAS/JRB and surrounding area are underlain by sedimentary rocks of the Triassic-age Stockton Formation, which form a complex, heterogeneous aquifer. The ground-water-flow system for the supply wells was characterized by use of borehole geophysical logs and heatpulse-flowmeter measurements. The heatpulse-flowmeter measurements showed upward and downward borehole flow under nonpumping conditions in both wells. The hydraulic and chemical properties of discrete water-bearing fractures in the supply wells were characterized by isolating each water-bearing fracture with straddle packers. Eight fractures in supply well 1 and five fractures in supply well 2 were selected for testing on the basis of the borehole geophysical logs and borehole television surveys. Water samples were collected from each isolated fracture and analyzed for VOC?s and inorganic constituents. Fractures at 50?59, 79?80, 196, 124?152, 182, 241, 256, and 350?354 ft btoc (feet below top of casing) were isolated in supply well 1. Specific capacities ranged from 0.26 to 5.7 (gal/min)/ft (gallons per minute per foot) of drawdown. The highest specific capacity was for the fracture isolated at 179.8?188 ft btoc. Specific capacity and depth of fracture were not related in either supply well. The highest concentrations of PCE were in water samples collected from fractures isolated at 236.8?245 and 249.8?258 ft btoc, which are hydraulically connected. The concentration of PCE generally increased with depth to a maximum of 39 mg/L (micrograms per liter) at a depth of 249.8? 258 ft btoc and then decreased to 21 mg/L at a

  4. Electromagnetic Borehole Flowmeter Testing at the Southwest Plume Test Pad

    SciTech Connect

    Flach, G.P.

    2001-01-29

    Multiple-well aquifer tests were recently conducted at the Southwest Plume Test Pad near the Burial Ground Complex (BGC) in accordance with the BGC Field Investigation Plan (WSRC, 1999). The pumping tests were performed in the Upper Three Runs and Gordon aquifers in February and March of 1999. The tests provide reliable estimates of horizontal conductivity averaged over aquifer thickness, and a relatively large horizontal zone of influence.

  5. Hydrogeology and simulation of flow between the alluvial and bedrock aquifers in the upper Black Squirrel Creek basin, El Paso County, Colorado

    USGS Publications Warehouse

    Watts, K.R.

    1995-01-01

    did not reliably estimate specific discharge across the bedrock surface. The vertical hydraulic diffusivity of a siltstone and sandstone in the lower Denver confining unit was estimated, by an aquifer test, to be about 8 x 10'4 square foot per day. Physical and chemical characteristics of water from the bedrock aquifers in the study area generally differ from the physical and chemical characteristics of water from the alluvial aquifer, except for the physical and chemical characteristics of water from one bedrock well, which is completed in the Laramie-Fox Hills aquifer. In the southern part of the study area, physical and chemical characteristics of ground water indicate downward flow of water from the alluvial aquifer to the Laramie-Fox Hills aquifer. A three-dimensional numerical model was used to evaluate flow of water between the alluvial aquifer and underlying bedrock. Simulation of steady-state conditions indicates that flow from the bedrock aquifers to the alluvial aquifer was about 7 percent of recharge to the alluvial aquifer, about 0.87 cubic foot per second. The potential effects of withdrawal from the alluvial and bedrock aquifers at estimated (October 1989 to September 1990) rates and from the bedrock aquifers at two larger hypothetical rates were simulated for a 50-year projection period. The model simulations indicate that water levels in the alluvial aquifer will decline an average of 8.6 feet after 50 years of pumping at estimated October 1989 to September 1990 rates. Increases in withdrawals from the bedrock aquifers in El Paso County were simulated to: (1) Capture flow that currently discharges from the bedrock aquifers to springs and streams in upland areas and to the alluvial aquifer, (2) induce flow downward from the alluvial aquifer, and (3) accelerate the rate of waterlevel decline in the alluvial aquifer.

  6. SUGGESTED OPERATING PROCEDURES FOR AQUIFER PUMPING TESTS

    EPA Science Inventory

    There has been an increased interest in ground water resources throughout the United States. This interest has resulted from a combination of an increase in fund water development for public and domestic use; an increase in mining, agricultural, and industrial activities which mi...

  7. Hydrologic and Geochemical Evaluation of Aquifer Storage Recovery in the Santee Limestone/Black Mingo Aquifer, Charleston, South Carolina, 1998-2002

    USGS Publications Warehouse

    Petkewich, Matthew D.; Parkhurst, David L.; Conlon, Kevin J.; Campbell, Bruce G.; Mirecki, June E.

    2004-01-01

    The hydrologic and geochemical effects of aquifer storage recovery were evaluated to determine the potential for supplying the city of Charleston, South Carolina, with large quantities of potable water during emergencies, such as earthquakes, hurricanes, or hard freezes. An aquifer storage recovery system, including a production well and three observation wells, was installed at a site located on the Charleston peninsula. The focus of this study was the 23.2-meter thick Tertiary-age carbonate and sand aquifer of the Santee Limestone and the Black Mingo Group, the northernmost equivalent of the Floridan aquifer system. Four cycles of injection, storage, and recovery were conducted between October 1999 and February 2002. Each cycle consisted of injecting between 6.90 and 7.19 million liters of water for storage periods of 1, 3, or 6 months. The volume of recovered water that did not exceed the U.S. Environmental Protection Agency secondary standard for chloride (250 milligrams per liter) varied from 1.48 to 2.46 million liters, which is equivalent to 21 and 34 percent of the total volume injected for the individual tests. Aquifer storage recovery testing occurred within two productive zones of the brackish Santee Limestone/Black Mingo aquifer. The individual productive zones were determined to be approximately 2 to 4 meters thick, based on borehole geophysical logs, electromagnetic flow-meter testing, and specific-conductance profiles collected within the observation wells. A transmissivity and storage coefficient of 37 meters squared per day and 3 x 10-5, respectively, were determined for the Santee Limestone/Black Mingo aquifer. Water-quality and sediment samples collected during this investigation documented baseline aquifer and injected water quality, aquifer matrix composition, and changes in injected/aquifer water quality during injection, storage, and recovery. A total of 193 water-quality samples were collected and analyzed for physical properties, major and

  8. Experiments in In-Situ Aquifer Denitrification

    NASA Astrophysics Data System (ADS)

    Khan, I. A.; Spalding, R. F.

    2001-05-01

    During the past five years, denitrification experiments have been conducted in sand and gravel aquifers. Successive experiments have provided data showing both pitfalls and successes in designing sustainable injection/extraction systems for ground water denitrification. Testing has evolved from simple one-well to eight-well injection systems, commonly referred as Daisy systems. Aquifer profiles of the performance of denitrification were determined by multilevel sampling in two-foot intervals within the denitrification zone. Continuous and pulsed injection of organic carbon were tested, and in both cases the 40 mg NO3-N L-1 was reduced to below the detection limit (< 0.1 mg NO3-N L-1). Under continuous injection, accumulation of bacterial material in the vicinity of the injection well resulted in injection well clogging within 10 days. Using a dipole tool developed in the Water Sciences Laboratory, periodic cleaning was accomplished by circulating a cleaning solution (5% H2O2 and 0.02% NaOCl) in the injection well and adjacent ground water. Pulse injections, in which the carbon is separated from the nitrate, successfully alleviated the proliferation of bacterial accumulations without adversely affecting the performance of the denitrification process. Given that ethanol favored enhanced bacterial growth and increased the potential for biofouling of the equipment, acetate became the preferred carbon amendment. About 45% of the nitrate was denitrified before interception in the production well during a three-month pulsed injection experiment using the full eight-well Daisy design. Draw down of nondenitrified water from the upper two-thirds of the aquifer supplied nitrate to the production well and thus limited system performance.

  9. Aquifer characterization at the Veterans Administration Hospital, Tuscaloosa, Alabama

    SciTech Connect

    Cronin, W.E.; Luttrell, S.P.; Hall, S.H.

    1989-10-01

    The Veterans Administration (VA) is studying the feasibility of aquifer thermal storage (ATES) at their Tuscaloosa, Alabama, facility. To determine the characteristics of the aquifer underlying the facility, the Pacific Northwest Laboratory gathered information about the environment of the aquifer and conducted tests to estimate the aquifer's transmissivity, ground-water flow direction, and velocity. Seven wells were drilled at the VA site. It was found that ground-water flow direction at the site is generally toward the southwest. The magnitude of the gradient is approximately 2.5 {times} 10{sup -3} to 3 {times} 10{sup -3} ft/ft. For six of the seven wells, clay lenses or thick clay layers appear to be acting locally as confining or semi-confining layers. Three types of test were conducted at the site: a step drawdown test, a constant discharge and recover test, and a single-well tracer test. The data yielded responses suggesting leaky confined or delayed yield models for the aquifer. Drawdown and recovery versus time were matched type curves for delayed yield to obtain estimates of transmissivity and storage. This recovery method gave the best fit to the drawdown-versus-time curves. Using this method it was found that transmissivity ranged from 500 to 9000 ft{sup 2}/day and storage ranged from 1.5 {times} 10{sup -4} to 4.5 {times} 10{sup -2} for the wells tested. Using the results of the pump and tracer tests simultaneously, ground-water velocity was estimated to be approximately 0.8 ft/day, with an effective porosity of approximately 12%. 4 refs., 7 figs., 3 tabs.

  10. Potential hydrologic effects of ground-water withdrawals from the Dakota Aquifer, southwestern Kansas

    USGS Publications Warehouse

    Watts, Kenneth R.

    1989-01-01

    A study was conducted to evaluate the effects of potential development of the Dakota aquifer on the layered-aquifer system above Permian rocks in a 5,000-square-mile area of southwestern Kansas. This aquifer system, which consists of five layers, includes the Cheyenne aquifer, the Kiowa confining unit, the Dakota aquifer, the Niobrara-Graneros confining unit, and the High Plains aquifer. Water supplies from the sandstone aquifers thus far have been developed mainly in parts of Hodgeman and Ford Counties. Management restrictions placed on further development of the High Plains aquifer could lead to additional development of the sandstone aquifers in the study area. The upper sandstone aquifer, the Dakota aquifer, consists of sandstone and shale of the Lower Cretaceous Dakota Sandstone and is as much as 400 feet thick. Transmissivity of the Dakota aquifer, determined from analyses of pumping tests, ranges from 100-7,100 feet squared per day. The Dakota aquifer is confined where it is overlain by the shales and limestones of the Upper Cretaceous Niobrara-Graneros confining unit, but locally it is unconfined. The lower sandstone aquifer, the Cheyenne aquifer, consists of the sandstone and shales of the Lower Cretaceous Cheyenne Sandstone in the eastern half of the study area plus undifferentiated Middle and Upper Jurassic rocks (sandstone, siltstone, shale, and limestone) in the western half of the study area. Maximum thickness of the Cheyenne aquifer is more than 300 feet, and maximum transmissivity is estimated at 3,000 feet squared per day. Estimated water use in the study area was about 8,800,000 acre-feet from the High Plains aquifer and about 160,000 acre-feet from the Dakota aquifer during 1975-82. The Cheyenne aquifer is not developed in the study area, and no water use from it is reported. The chemical characteristics of water in the sandstone aquifers are highly variable in the study area. Water in the Dakota aquifer is a calcium bicarbonate type water

  11. Estimation of hydraulic parameters in a complex porous aquifer system using geoelectrical methods.

    PubMed

    Kazakis, N; Vargemezis, G; Voudouris, K S

    2016-04-15

    Geoelectrical methods have been widely used for the estimation of aquifer hydraulic properties. In this study, geoelectrical methods were applied in a lithologically and hydrochemically complex porous aquifer to estimate its porosity, hydraulic conductivity and transmissivity. For this purpose, the electrical resistivity of the aquifer as well as the electrical conductivity of the groundwater was measured in 37 sites and wells. Initially, the Archie's law was used to generate sets of cementation factor (m) and alpha (α) parameter from which the mode values of α=0.98 and m=1.75 are representative of the studied aquifer. The transmissivity of the aquifer varies from 5.1×10(-3) to 3.1×10(-5)m(2)/s, whereas the mean value of its porosity is 0.45. The hydraulic conductivity of the aquifer which was calculated according to Archie's law varies from 2.08×10(-6) to 6.84×10(-5)m/s and is strongly correlated with the pumping test's hydraulic conductivity. In contrast, the hydraulic conductivity which was calculated using Dar-Zarrouk parameters presents lower correlation with the pumping test's hydraulic conductivity. Furthermore, a relation between aquifer resistivity and hydraulic conductivity was established for the studied aquifer to enable the estimation of these parameters in sites lacking data.

  12. Mapping the vulnerability of groundwater to the contamination of four carbonate aquifers in Europe.

    PubMed

    Vías, J; Andreo, B; Ravbar, N; Hötzl, H

    2010-07-01

    The vulnerability of four European aquifers with different hydrogeological and climatic characteristics was evaluated using the COP method. The results obtained were statistically analyzed by determination coefficients to measure which factor has greater importance in the vulnerability index. Furthermore, a new parameter has been designed to measure the vulnerability for the whole of the aquifer. The results demonstrate that COP is a useful method to assess the vulnerability of the test sites under consideration. The results obtained are coherent with the conceptual model of each pilot aquifer and the available hydrogeological information (hydrographs, isotopic data, tracer tests). Fissured carbonate aquifers (diffuse flow systems) are less vulnerable than karst aquifers (conduit flow systems) and the vulnerability index is more positively correlated with the O factor (unsaturated zone protection capacity) in the first case. The karst aquifers are more vulnerable than fissured aquifers and they show a higher correlation between the C factor (karst features) and the vulnerability index. Climatic variation (precipitation for example) influences the final vulnerability index of the aquifers according to the weight in the index and the spatial distribution.

  13. Hydraulic head response of a confined aquifer influenced by river stage fluctuations and mechanical loading

    NASA Astrophysics Data System (ADS)

    Pacheco, F. A. L.; Fallico, C.

    2015-12-01

    The response to river stage fluctuation of a drilled well penetrating a confined aquifer was simulated using a stream-aquifer interaction algorithm. Because the confined aquifer is overlaid by a water table aquifer, the algorithm was coupled with formulae used to correct the heads for mechanical loading. The coupling of stream-aquifer interaction and mechanical loading models was tried for the first time in this study. The test site was a drilled well installed on the Montalto Uffugo aquifer located at the Calabria University groundwater test field (Calabria region, south of Italy). This aquifer comprises a 44 m-thick sand bank bounded on bottom and top by clay layers and covered by a 7 m-thick sandy conglomerate, being adjacent to the Mavigliano River. Overall, the head changes caused by a river stage raise represented a contribution of 49.3-57.8% to the total head, while mechanical loading accounted for the remaining 50.7-32.2%. The loading was triggered by a sequence of short-spaced rainfall events lasting for a total of 167 days, which caused recharge to the unconfined aquifer thickening the water column by some 3.1 m.

  14. Preparation of specific-yield logs for clastic bedrock aquifers

    USGS Publications Warehouse

    Robson, S.G.

    1995-01-01

    Specific yield is the principal aquifer characteristic needed to estimate the volume of recoverable ground water in storage in an aquifer. Determination of specific yield can be difficult and costly, particularly in deep, confined aquifers where core drilling and core analyses may be needed to define specific yield. A method has been developed for preparation of specific-yield geophysical logs that could greatly ease the determination of specific yields in such aquifers. Three geophysical logs that were investigated as potential indicators of specific yield were the free fluid index log, the effective-porosity log, and the apparent grain-density log. The free fluid index log did not accurately represent conditions at the test site in central Colorado and may not be suitable for application in other shallow and permeable aquifers. The effective-porosity and apparent grain-density logs were each used in least-squares linear regressions to correlate log response to specific yield measured in core samples. The resulting regression equations have coefficients of correlation (R) of 0.84 and 0.90, and were used to successfully prepare specific-yield logs from the effective-porosity and apparent grain-density logs.

  15. ANALYTICAL ELEMENT MODELING OF COASTAL AQUIFERS

    EPA Science Inventory

    Four topics were studied concerning the modeling of groundwater flow in coastal aquifers with analytic elements: (1) practical experience was obtained by constructing a groundwater model of the shallow aquifers below the Delmarva Peninsula USA using the commercial program MVAEM; ...

  16. Reef and nonreef aquifers - A comparison of hydrogeology and geochemistry, northwestern Indiana

    USGS Publications Warehouse

    Schnoebelen, D.J.; Krothe, N.C.

    1999-01-01

    The principal bedrock aquifer system across much of Indiana consists of carbonate rocks of Silurian and Devonian age. The Silurian-Devonian aquifer system is used extensively for irrigation in northwestern Indiana and is approximately 170 m thick. Reef and nonreef carbonate aquifers in northwestern Indiana were assessed using hydrogeology (lithology, geophysical logs, aquifer tests) and geochemistry (major ions and stable isotopes). The study showed differences in water quantity and quality between the reef and nonreef aquifers. The reef aquifer had few shales, abundant fossiliferous material (up to 100 m thick), and high porosities (10 to 15%). The nonreef aquifer had abundant shales, less fossiliferous material (a few meters thick), and low porosities. Total transmissivities at the reef sites were 697 m2/d, (meters squared per day) and 4831 m2/d, compared to 46 m2/d at the nonreef site. Flowpaths in the nonreef aquifer were associated with fractures and poorly connected moldic porosity with larger fractures and better connected vuggy porosity in the reef aquifer. Water chemistry data for the nonreef aquifer showed mean concentrations of sodium (235 mg/L [milligrams per liter]), sulfate (160 mg/L), sulfide (13 mg/L), fluoride (2.7 mg/L), and dissolved solids (635 mg/L) approximately two to five times larger when compared to mean concentrations in the reef aquifer. Ground water at the nonreef site was classified as a sodium-bicarbonate type while that at the reef sites was calcium-magnesium bicarbonate. The oxygen/deuterium isotope data indicates recharge from modern precipitation and not Pleistocene-age recharge.The principal bedrock aquifer system across much of Indiana consists of carbonate rocks of Silurian and Devonian age. The Silurian-Devonian aquifer system is used extensively for irrigation in northwestern Indiana and is approximately 170 m thick. Reef and nonreef carbonate aquifers in northwestern Indiana were assessed using hydrogeology (lithology

  17. Microbial risk assessment in heterogeneous aquifers: 1. Pathogen transport

    NASA Astrophysics Data System (ADS)

    Molin, S.; Cvetkovic, V.

    2010-05-01

    Pathogen transport in heterogeneous aquifers is investigated for microbial risk assessment. A point source with time-dependent input of pathogens is assumed, exemplified as a simple on-site sanitation installation, intermingled with water supply wells. Any pathogen transmission pathway (realization) to the receptor from a postulated infection hazard is viewed as a random event, with the hydraulic conductivity varying spatially. For aquifers where VAR[lnK] < 1 and the integral scale is finite, we provide relatively simple semianalytical expressions for pathogen transport that incorporate the colloid filtration theory. We test a wide range of Damkohler numbers in order to assess the significance of rate limitations on the aquifer barrier function. Even slow immobile inactivation may notably affect the retention of pathogens. Analytical estimators for microbial peak discharge are evaluated and are shown to be applicable using parameters representative of rotavirus and Hepatitis A with input of 10-20 days duration.

  18. Analysis of hydrogeologic properties in the Prairie du Chien-Jordan aquifer, Shakopee Mdewakanton Sioux Community, southeastern Minnesota

    USGS Publications Warehouse

    Strobel, M.L.; Delin, G.N.

    1996-01-01

    The Neuman (1974) method for unconfined aquifers was used to analyze data collected from the two observation wells during the drawdown and recovery periods, resulting in a range of estimated aquifer hydraulic properties. Aquifer transmissivity ranged from 4,710 to 7,660 ft2/d and aquifer storativity ranged from 8.24 x 10-5 to 1.60 x 10-4. These values are generally in close agreement for all four sets of data, given the limitations of the test, indicating that the test results are accurate and representative of the aquifer hydrogeologic properties. The lack of late-time data made it impossible to accurately assess aquifer specific yield.

  19. Methanotrophic Bacteria and Facilitated Transport of Pollutants in Aquifer Material

    PubMed Central

    Jenkins, Michael B.; Chen, Jyh-Herng; Kadner, Debra J.; Lion, Leonard W.

    1994-01-01

    for phenanthrene with an aquifer sand. The three strains of methanotrophs tested displayed mobility in a column of packed sand, and strain OBBP reduced the retardation coefficient of phenanthrene with an aquifer sand by 27%. These data indicate that both extracellular polymer and mobile cells of methanotrophic bacteria display a capacity to facilitate the mobility of pollutant metals and polynuclear aromatic hydrocarbons in aquifer material. PMID:16349401

  20. Methanotrophic bacteria and facilitated transport of pollutants in aquifer material.

    PubMed

    Jenkins, M B; Chen, J H; Kadner, D J; Lion, L W

    1994-10-01

    phenanthrene with an aquifer sand. The three strains of methanotrophs tested displayed mobility in a column of packed sand, and strain OBBP reduced the retardation coefficient of phenanthrene with an aquifer sand by 27%. These data indicate that both extracellular polymer and mobile cells of methanotrophic bacteria display a capacity to facilitate the mobility of pollutant metals and polynuclear aromatic hydrocarbons in aquifer material.

  1. 40 CFR 147.1352 - Aquifer exemptions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 23 2014-07-01 2014-07-01 false Aquifer exemptions. 147.1352 Section 147.1352 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS... Aquifer exemptions. Those portions of aquifers within one-quarter mile of existing Class II wells...

  2. 40 CFR 147.1352 - Aquifer exemptions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 23 2011-07-01 2011-07-01 false Aquifer exemptions. 147.1352 Section 147.1352 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS... Aquifer exemptions. Those portions of aquifers within one-quarter mile of existing Class II wells...

  3. 40 CFR 147.1352 - Aquifer exemptions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 24 2013-07-01 2013-07-01 false Aquifer exemptions. 147.1352 Section 147.1352 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS... Aquifer exemptions. Those portions of aquifers within one-quarter mile of existing Class II wells...

  4. 40 CFR 147.1352 - Aquifer exemptions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 24 2012-07-01 2012-07-01 false Aquifer exemptions. 147.1352 Section 147.1352 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS... Aquifer exemptions. Those portions of aquifers within one-quarter mile of existing Class II wells...

  5. 40 CFR 147.1352 - Aquifer exemptions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Aquifer exemptions. 147.1352 Section 147.1352 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS... Aquifer exemptions. Those portions of aquifers within one-quarter mile of existing Class II wells...

  6. Digital computer simulation model of the Englishtown aquifer in the northern coastal plain of New Jersey

    USGS Publications Warehouse

    Nichols, W.D.

    1977-01-01

    Continued decline of water levels in the Englishtown aquifer, in New Jersey, has caused considerable concern regarding the ability of the aquifer to meet future yield demands. A detailed study of the capability of the aquifer to yield water entailed the use of a digital computer simulation model to evaluate aquifer and confining layer coefficients and to test alternative concepts of the hydrodynamics of the flow system. The modeled area includes about 750 square miles of the northern Coastal Plain of New Jersey and encompasses all the major centers of pumping from the Englishtown aquifer. The simulation model was calibrated by matching computed declines with historical water-level declines over the 12-year period, 1959-70. The volume of transient and steady leakage into the Englishtown aquifer from and through the adjacent confining layers equaled more than 90 percent of the total volume of water withdrawn from the aquifer between 1959 and 1970. The analytical estimate of transient leakage indicates that about 60 percent of the water withdrawn from the Englishtown between 1959 and 1970 was replaced by water released from storage in the adjacent confining beds. An additional 34 percent of the withdrawal over this time period was supported by steady leakage through the overlying confining bed from the Mount Laurel aquifer. Of the more than 30 billion gallons withdrawn from the aquifer over the 12-year period, about 2 billion gallons were obtained from storage in the aquifer. The values of aquifer and confining-layer coefficients used in the model are nearly the same as the average values obtained from field and laboratory data. (Woodard-USGS)

  7. Hydrogeology of the gray limestone aquifer in southern Florida

    USGS Publications Warehouse

    Reese, Ronald S.; Cunningham, Kevin J.

    2000-01-01

    Results from 35 new test coreholes and aquifer-test, water-level, and water-quality data were combined with existing hydrogeologic data to define the extent, thickness, hydraulic properties, and degree of confinement of the gray limestone aquifer in southern Florida. This aquifer, previously known to be present only in southeastern Florida (Miami-Dade, Broward, and Palm Beach Counties) below, and to the west of, the Biscayne aquifer, extends over most of central-south Florida, including eastern and central Collier County and southern Hendry County; it is the same as the lower Tamiami aquifer to the north, and it becomes the water-table aquifer and the upper limestone part of the lower Tamiami aquifer to the west. The aquifer generally is composed of gray, shelly, lightly to moderately cemented limestone with abundant shell fragments or carbonate sand, abundant skeletal moldic porosity, and minor quartz sand. The gray limestone aquifer comprises the Ochopee Limestone of the Tamiami Formation, and, in some areas, the uppermost permeable part of an unnamed formation principally composed of quartz sand. Underlying the unnamed formation is the Peace River Formation of the upper Hawthorn Group, the top of which is the base of the surficial aquifer system. Overlying the aquifer and providing confinement in much of the area is the Pinecrest Sand Member of the Tamiami Formation. The thickness of the aquifer is comparatively uniform, generally ranging from 30 to 100 feet. The unnamed formation part of the aquifer is up to 20 feet thick. The Ochopee Limestone accumulated in a carbonate ramp depositional system and contains a heterozoan carbonate-particle association. The principal rock types of the aquifer are pelecypod lime rudstones and floatstones and permeable quartz sands and sandstones. The pore types are mainly intergrain and separate vug (skeletal-moldic) pore spaces. The rock fabric and associated primary and secondary pore spaces combine to form a dual diffuse

  8. Geology of the surficial aquifer system, Broward County, Florida; lithologic logs

    USGS Publications Warehouse

    Causaras, C.R.

    1985-01-01

    The geologic framework of the surficial aquifer system, of which the Biscayne aquifer is the major component in Broward County, Florida, is presented in eight geologic cross sections. The cross sections are based on detailed lithologic logs of 27 test wells that were drilled, in the summer of 1981, through the sediments overlying the relatively impermeable units of the Hawthorn Formation, of Miocene age. The cross sections show the aquifer system as a wedge-shaped sequence of Cenozoic sediments. The aquifer thickness gradually decreases from more than 400 feet along the coast to about 160 feet in the west and southwest parts of Broward County. The sediments that comprise the aquifer system range in age from Pliocene to Pleistocene and are assigned to the following stratigraphic units from bottom to top: Tamiami Formation, Caloosahatchee Marl, Fort Thompson Formation, Key Largo Limestone, Anastasia Formation, Miami Oolite, and Pamlico Sand. (USGS)

  9. Application of a discrete-continuum model to karst aquifers in North China.

    PubMed

    Wu, Qiang; Zhou, Wanfang; Pan, Guoying; Ye, Siyuan

    2009-01-01

    A generalized discrete-continuum model is developed to simulate ground water flow in the karst aquifers of North China. The model is a hybrid numerical flow model, which takes into account both quick conduit flow and diffusive fissure flow. The conduit flow is represented by a discrete network model, and the fissure flow is modeled by a continuum approach. The developed model strongly emphasizes the function of the conduits in the flow fields. They control the general drainage pattern, as demonstrated in the simulation of a complex karst aquifer in North China. The model reproduces reasonably well the flow field in response to an unanticipated discharge of ground water from the karst aquifer into an underground mine based on the aquifer parameters that are manually calibrated from a multiple-well pumping test. Sensitivity of the model to the aquifer parameters was evaluated in the context of the case study.

  10. Hydrogeology and water quality of the Dublin and Midville aquifer systems at Waynesboro, Burke County, Georgia, 2011

    USGS Publications Warehouse

    Gonthier, Gerard J.

    2013-01-01

    The hydrogeology and water quality of the Dublin and Midville aquifer systems were characterized in the City of Waynesboro area in Burke County, Georgia, based on geophysical and drillers’ logs, flowmeter surveys, a 24-houraquifer test, and the collection and chemical analysis of water samples in a newly constructed well. At the test site, the Dublin aquifer system consists of interlayered sands and clays between depths of 396 and 691 feet, and the Midville aquifer system consists of a sandy clay layer overlying a sand and gravel layer between depths of 728 and 936 feet. The new well was constructed with three screened intervals in the Dublin aquifer system and four screened intervals in the Midville aquifer system. Wellbore-flowmeter testing at a pumping rate of 1,000 gallons per minute indicated that 52.2 percent of the total flow was from the shallower Dublin aquifer system with the remaining 47.8 percent from the deeper Midville aquifer system. The lower part of the lower Midville aquifer (900 to 930 feet deep), contributed only 0.1 percent of the total flow. Hydraulic properties of the two aquifer systems were estimated using data from two wellbore-flowmeter surveys and a 24-hour aquifer test. Estimated values of transmissivity for the Dublin and Midville aquifer systems were 2,000 and 1,000 feet squared per day, respectively. The upper and lower Dublin aquifers have a combined thickness of about 150 feet and the horizontal hydraulic conductivity of the Dublin aquifer system averages 10 feet per day. The upper Midville aquifer, lower Midville confining unit, and lower Midville aquifer have a combined thickness of about 210 feet, and the horizontal hydraulic conductivity of the Midville aquifer system averages 6 feet per day. Storage coefficient of the Dublin aquifer system, computed using the Theis method on water-level data from one observation well, was estimated to be 0.0003. With a thickness of about 150 feet, the specific storage of the Dublin aquifer

  11. Ground-Water Availability from the Hawi Aquifer in the Kohala Area, Hawaii

    USGS Publications Warehouse

    Underwood, Mark R.; Meyer, William; Souza, William R.

    1995-01-01

    A ground-water study consisting of test-well drilling, aquifer tests, and numerical simulation was done to investigate ground-water availability in the basal part of the Hawi aquifer between the western drainage divide of Pololu Valley and Upolu Point in Kohala, Hawaii. The test-well drilling provided information on geology, water levels, water quality, vertical extent of the freshwater, and the thickness of the freshwater-saltwater transition zone in that aquifer. A total of 12 test wells were drilled at eight locations. Aquifer tests were done at five locations to estimate the hydraulic conductivity of the aquifer. Using information on the distribution of recharge, vertical extent of freshwater, hydraulic conductivity, and geometry of the basal aquifer, a numerical model was used to simulate the movement of water into, through, and out of the basal aquifer, and the effect of additional pumping on the water levels in the aquifer. Results of the modeling indicate that ground-water withdrawal of 20 million gallons per day above the existing withdrawal of 0.6 million gallons per day from the basal aquifer is hydrologically feasible, but that spacing, depth, and pumping rates of individual wells are important. If pumping is concentrated, the likelihood of saltwater intrusion is increased. The additional withdrawal of 20 million gallons per day would result in a reduction of ground-water discharge to the ocean by an amount equal to pumpage. Although model-calculated declines in water-level outside the area of pumping are small, pumping could cause some reduction of streamflow near the mouth of Pololu Stream.

  12. Field evidence of hydraulic connections between bedrock aquifers and overlying granular aquifers: examples from the Grenville Province of the Canadian Shield

    NASA Astrophysics Data System (ADS)

    Richard, Sandra K.; Chesnaux, Romain; Rouleau, Alain; Morin, Roger; Walter, Julien; Rafini, Silvain

    2014-12-01

    Field evidence of hydraulic connections between a bedrock aquifer and an overlying granular aquifer in the Canadian Shield (Grenville Province) is presented. This issue is rarely considered and investigated despite its important hydraulic and chemical consequences and its widespread occurrence worldwide. The methodology employed is based on complementary field tests conducted at specific experimental sites instrumented both in the rock and in the overlying deposits. One of the bedrock sites revealed a natural hydraulic connection with the overlying granular aquifer caused by the weathered surface of the uppermost bedrock. Another site revealed an artificial hydraulic connection between the bedrock and the granular aquifer created by an improperly sealed casing. A regional study showed that hydraulic connections yield an erroneous interpretation of the true hydraulic properties of the tested aquifer. The detection of hydraulic connections is therefore essential to properly define well-capture areas and contamination conditions. It is recommended to practitioners that pumping tests be performed as well as hydrochemical comparisons of each existing aquifer unit. Falling-head permeability tests are also helpful in verifying the quality of the seal at the bedrock-casing contact. More effective procedural controls and better well-construction practices are necessary to reduce the risks of cross-contamination induced by defective seals.

  13. Hydrogeology of aquifers in Cretaceous and younger rocks in the vicinity of Onslow and southern Jones counties, North Carolina

    USGS Publications Warehouse

    Lyke, W.L.; Winner, M.D.

    1990-01-01

    Unconsolidated sediments in Onslow and Jones Counties, North Carolina overlie crystalline basement rocks and range in thickness from about 700 ft to more than 1,800 ft, thickening toward the east. This material is composed of permeable sand and limestone interlayered with relatively impermeable clay and silt beds. Sediments are divided into two groups: aquifers in Quaternary-, and Tertiary-aged rocks and aquifers in Cretaceous-aged rocks. Aquifers in the Cretaceous rocks provide most of the groundwater for public supplies and are the focus of this report. The aquifers in Cretaceous rocks are the Peedee, Black Creek, upper Cape Fear, and lower Cape Fear aquifers, which are composed of beds or groups of beds of sand and gravel. Each aquifer is overlain by a clay and silt bed, that impedes the flow of water between aquifers. The thickness of Cretaceous hydrogeologic units ranges from about 700 ft to more than 1, 300 ft. Hydrogeologic units are correlated using 60 geophysical logs and accompanying drillers ' logs along with water level and water quality data. Three hydrogeologic sections demonstrate the continuity of the aquifers and confining units, show water levels and chloride concentration in water from test intervals, and delineate where chloride concentration in water exceeds 250 mg/L within each aquifer. Maps of each aquifer in Cretaceous rocks show altitude of its top, thickness, sand percentage, and the transition from freshwater to saltwater. Maps of the confining units show thickness and sand percentage of each.

  14. Modeling of aquifer movement due to seismic and hydraulic forces

    NASA Astrophysics Data System (ADS)

    Xu, Aiguo

    A mathematical description of aquifer movement due to inertial and viscous forces is formulated by applying fundamental physical principles such as mass balance and momentum balance to a saturated aquifer system. An explicit interaction term in the momentum balance equation for the water phase sharing the same mathematical space with the solid phase introduced in the derivation of the governing equation system of aquifer movement distinguishes the development in this study from those of others such as Li's and that of Zienkiewicz and Bettess. The solid matrix is assumed to be a Helm-Li material which deforms as a highly non-linear viscous fluid rather than as the conventional poroelastic material. The finite element method is applied to solve three simplified situations: (a) negligible relative acceleration; (b) negligible acceleration of water; and (c) negligible bulk acceleration. Helm's bulk flux concept is applied in the simplifications. A computer code called Aquivis3d is developed in order to calculate the velocity and displacement of aquifer movement due to both inertial and viscous forces. Evaluation of the numerical model is accomplished by applying the code to different cases which include: standard laboratory consolidation tests; one dimensional radial movement of a Theis-Thiem aquifer; and a disturbance propagation. Simulation results favorably fit laboratory measurements for selected consolidation tests. Simulation results of one dimensional radial movement of a Theis-Thiem aquifer based in this study on poroviscosity are similar in general features to Helm's analytical results based on poroelasticity. Frequency dispersion and intensity attenuation of a disturbance propagation are fully simulated without any additional ad hoc damping assumption for dynamic aquifer movement. Sensitivity analyses are made for the viscous constitutive parameters and the hydraulic parameters in the consolidation and the one dimensional radial movement of a Theis

  15. Identification and quantification of redox and pH buffering processes in a heterogeneous, low carbonate aquifer during managed aquifer recharge

    NASA Astrophysics Data System (ADS)

    Seibert, Simone; Atteia, Olivier; Ursula Salmon, S.; Siade, Adam; Douglas, Grant; Prommer, Henning

    2016-05-01

    Managed aquifer recharge of aerobic water into deep aquifers often induces the oxidation of pyrite, which can lead to groundwater acidification and metal mobilization. As circumneutral pH is often maintained by the dissolution of sedimentary calcite or high injectant alkalinity little attention is generally paid to potential alternative pH buffering processes. In contrast, this study analyzed water quality evolution from a 2 year long groundwater replenishment trial in an anaerobic, mostly carbonate free aquifer. While injection of aerobic, very low salinity water triggered pyrite oxidation, the comprehensive field data showed that in many aquifer zones pH was buffered without substantial release of inorganic carbon. A numerical analysis was performed to test and evaluate different conceptual models and suggested that either proton buffering or the dissolution of aluminosilicates, or a combination thereof, can explain the observed, rapid buffering at locations where carbonates were absent. In contrast to many previous managed aquifer recharge [MAR) studies, the oxidation of sedimentary pyrite by nitrate was found to be of minor importance or negligible. The study also highlights that the depositional history of the aquifer, and the associated differences in mineralogy and geochemistry, need to be considered when estimating groundwater quality evolution during the injection of various water types for aquifer replenishment or other management purposes.

  16. Mobilization and micellar solubilization of NAPL contaminants in aquifer rocks

    NASA Astrophysics Data System (ADS)

    Javanbakht, Gina; Goual, Lamia

    2016-02-01

    Surfactant-enhanced aquifer remediation is often performed to overcome the capillary forces that keep residual NAPL phases trapped within contaminated aquifers. The surfactant selection and displacement mechanism usually depend on the nature of NAPL constituents. For example, micellar solubilization is often used to cleanup DNAPLs from aquifers whereas mobilization is desirable in aquifers contaminated by LNAPLs. Although the majority of crude oils are LNAPLs, they often contain heavy organic macromolecules such as asphaltenes that are classified as DNAPLs. Asphaltenes contain surface-active components that tend to adsorb on rocks, altering their wettability. Previous studies revealed that surfactants that formed Winsor type III microemulsions could promote both mobilization and solubilization. However the extent by which these two mechanisms occur is still unclear, particularly in oil-contaminated aquifers. In this study we investigated the remediation of oil-contaminated aquifers using an environmentally friendly surfactant such as n-Dodecyl β-D-maltoside. Focus was given on asphaltenes to better understand the mechanisms of surfactant cleanup. Through phase behavior, spontaneous imbibition, dynamic interfacial tension and contact angle measurements, we showed that microemulsions formed by this surfactant are able to mobilize bulk NAPL (containing 9 wt.% asphaltenes) in the porous rock and solubilize DNAPL (i.e., 4-6 wt.% adsorbed asphaltenes) from the rock surface. Spontaneous imbibition tests, in particular, indicated that the ratio of mobilized to solubilized NAPL is about 6:1. Furthermore, aging the cores in NAPL beyond 3 days allowed for more NAPL to be trapped in the large pores of the rock but did not alter the amount of asphaltenes adsorbed on the mineral surface.

  17. Mobilization and micellar solubilization of NAPL contaminants in aquifer rocks.

    PubMed

    Javanbakht, Gina; Goual, Lamia

    2016-01-01

    Surfactant-enhanced aquifer remediation is often performed to overcome the capillary forces that keep residual NAPL phases trapped within contaminated aquifers. The surfactant selection and displacement mechanism usually depend on the nature of NAPL constituents. For example, micellar solubilization is often used to cleanup DNAPLs from aquifers whereas mobilization is desirable in aquifers contaminated by LNAPLs. Although the majority of crude oils are LNAPLs, they often contain heavy organic macromolecules such as asphaltenes that are classified as DNAPLs. Asphaltenes contain surface-active components that tend to adsorb on rocks, altering their wettability. Previous studies revealed that surfactants that formed Winsor type III microemulsions could promote both mobilization and solubilization. However the extent by which these two mechanisms occur is still unclear, particularly in oil-contaminated aquifers. In this study we investigated the remediation of oil-contaminated aquifers using an environmentally friendly surfactant such as n-Dodecyl β-D-maltoside. Focus was given on asphaltenes to better understand the mechanisms of surfactant cleanup. Through phase behavior, spontaneous imbibition, dynamic interfacial tension and contact angle measurements, we showed that microemulsions formed by this surfactant are able to mobilize bulk NAPL (containing 9wt.% asphaltenes) in the porous rock and solubilize DNAPL (i.e., 4-6wt.% adsorbed asphaltenes) from the rock surface. Spontaneous imbibition tests, in particular, indicated that the ratio of mobilized to solubilized NAPL is about 6:1. Furthermore, aging the cores in NAPL beyond 3days allowed for more NAPL to be trapped in the large pores of the rock but did not alter the amount of asphaltenes adsorbed on the mineral surface. PMID:26826983

  18. Mobilization and micellar solubilization of NAPL contaminants in aquifer rocks.

    PubMed

    Javanbakht, Gina; Goual, Lamia

    2016-01-01

    Surfactant-enhanced aquifer remediation is often performed to overcome the capillary forces that keep residual NAPL phases trapped within contaminated aquifers. The surfactant selection and displacement mechanism usually depend on the nature of NAPL constituents. For example, micellar solubilization is often used to cleanup DNAPLs from aquifers whereas mobilization is desirable in aquifers contaminated by LNAPLs. Although the majority of crude oils are LNAPLs, they often contain heavy organic macromolecules such as asphaltenes that are classified as DNAPLs. Asphaltenes contain surface-active components that tend to adsorb on rocks, altering their wettability. Previous studies revealed that surfactants that formed Winsor type III microemulsions could promote both mobilization and solubilization. However the extent by which these two mechanisms occur is still unclear, particularly in oil-contaminated aquifers. In this study we investigated the remediation of oil-contaminated aquifers using an environmentally friendly surfactant such as n-Dodecyl β-D-maltoside. Focus was given on asphaltenes to better understand the mechanisms of surfactant cleanup. Through phase behavior, spontaneous imbibition, dynamic interfacial tension and contact angle measurements, we showed that microemulsions formed by this surfactant are able to mobilize bulk NAPL (containing 9wt.% asphaltenes) in the porous rock and solubilize DNAPL (i.e., 4-6wt.% adsorbed asphaltenes) from the rock surface. Spontaneous imbibition tests, in particular, indicated that the ratio of mobilized to solubilized NAPL is about 6:1. Furthermore, aging the cores in NAPL beyond 3days allowed for more NAPL to be trapped in the large pores of the rock but did not alter the amount of asphaltenes adsorbed on the mineral surface.

  19. Hydrogeology and simulation of ground-water flow in the aquifers underlying Belvidere, Illinois

    USGS Publications Warehouse

    Mills, Patrick C.; Nazimek, J.E.; Halford, K.J.; Yeskis, D.J.

    2002-01-01

    through fractures and bedding-plane partings. Estimated horizontal hydraulic conductivity ranges from about 0.005 to 2,500 feet per day. Estimated horizontal hydraulic conductivity of the St. Peter aquifer (the uppermost sandstone aquifer of the Cambrian-Ordovician aquifer system ranges from about 4.7 to 17.5 feet per day. Volatile organic compounds have been detected in all aquifers underlying Belvidere. Trichloroethene and tetrachloroethene are the principal VOC?s detected at concentrations above regulatory levels, with the largest number of detections and highest concentrations in the glacial drift aquifer. VOC?s generally are not detected in the glacial drift aquifer farther than 1,000 feet from known or potential source areas (industrial or disposal sites), because most source areas are near the Kishwaukee River, where shallow ground water discharges. Across most of the study area, the Glenwood confining unit seems to restrict downward movement of VOC?s into the underlying St. Peter aquifer; in the immediate vicinity of Belvidere, downward movement also seems restricted by lateral movement toward the municipal wells through permeable intervals in the 2 Hydrogeology and Simulation of Ground-Water Flow in the Aquifers Underlying Belvidere, Illinois Galena-Platteville aquifer. Fractures and (or) unused wells that may penetrate the confining unit seem to provide local pathways for limited movement of VOC?s to the sandstone aquifers. At least two municipal wells seem to intercept the bedding-plane partings at about 525 and 485 feet above sea level. Water levels in the lower one-third of the Galena-Platteville aquifer rapidly respond to withdrawals at these wells. The ground-water-flow system underlying Belvidere was simulated to test the conceptual model of the system. The three-dimensional, steady-state model represents the glacial drift, Galena-Platteville, and sandstone aquifers sep

  20. Denitrification in a Sand and Gravel Aquifer

    PubMed Central

    Smith, Richard L.; Duff, John H.

    1988-01-01

    Denitrification was assayed by the acetylene blockage technique in slurried core material obtained from a freshwater sand and gravel aquifer. The aquifer, which has been contaminated with treated sewage for more than 50 years, had a contaminant plume greater than 3.5-km long. Near the contaminant source, groundwater nitrate concentrations were greater than 1 mM, whereas 0.25 km downgradient the central portion of the contaminant plume was anoxic and contained no detectable nitrate. Samples were obtained along the longitudinal axis of the plume (0 to 0.25 km) at several depths from four sites. Denitrification was evident at in situ nitrate concentrations at all sites tested; rates ranged from 2.3 to 260 pmol of N2O produced (g of wet sediment)−1 h−1. Rates were highest nearest the contaminant source and decreased with increasing distance downgradient. Denitrification was the predominant nitrate-reducing activity; no evidence was found for nitrate reduction to ammonium at any site. Denitrifying activity was carbon limited and not nitrate limited, except when the ambient nitrate level was less than the detection limit, in which case, even when amended with high concentrations of glucose and nitrate, the capacity to denitrify on a short-term basis was lacking. These results demonstrate that denitrification can occur in groundwater systems and, thereby, serve as a mechanism for nitrate removal from groundwater. PMID:16347621

  1. Distribution of transmissivity and yield of the surficial, Castle Hayne, and Peedee aquifers in Northern New Hanover County, North Carolina

    USGS Publications Warehouse

    McSwain, Kristen Bukowski; Nagy, Laura A.

    2011-01-01

    Data were collected from more than 230 wells in northern New Hanover County, North Carolina, to evaluate the distribution of transmissivity and yield of the surficial, Castle Hayne, and Peedee aquifers of the Coastal Plain Physiographic Province. Constant-rate,single-well aquifer test data were obtained and analyzed to calculate additional transmissivity values for 25 production wells that were completed in the Castle Hayne or Peedee aquifer. In the surficial aquife, transmissivity values ranged from 400 to 12,700 feet squared per day, and reported yields ranged from 6 to 100 gallons per minute. In the Castle Hayne aquifer, transmissivity values ranged from 1,400 to 18,700 feet squared per day, and reported yields ranged from 9 to 640 gallons per minute. In the Peedee aquifer, transmissivity values ranged from 530 to 18,600 feet squared per day, and reported yields ranged from 8 to 1,000 gallons per minute.

  2. Aquifer properties, stream base flow, water use, and water levels in the Pohatcong Valley, Warren County, New Jersey

    USGS Publications Warehouse

    Carleton, G.B.; Gordon, A.D.; Wieben, C.M.

    2005-01-01

    A study was conducted to define the hydrogeology and describe the ground-water flow in the Pohatcong Valley in Warren County, N.J. near the Pohatcong Valley Ground Water Contamination Site. The area is underlain by glacial till and alluvial sediments and weathered and competent carbonate bedrock. The northwest and southeast valley boundaries are regional-scale thrust faults and ridges underlain by crystalline rocks. The unconsolidated sediments and weathered bedrock form a minor surficial aquifer. The carbonate rocks form a highly transmissive fractured-rock aquifer with well yields commonly as high as 500 gallons per minute. Ground-water recharge and flow in the crystalline-rock aquifer bordering the valley is minor compared to flow in the carbonate-rock aquifer, and little ground water flows into the carbonate-rock aquifer directly from the crystalline-rock aquifer. The thrust faults separating the carbonate and crystalline rocks may further impede flow between the two rock types. Interpretations of water-level and transmissivity data collected during 2000 to 2003 indicate that the carbonate formations generally can be considered to be one aquifer. The transmissivity of the carbonate-rock aquifer was estimated from the results of four aquifer tests conducted with two public supply wells. The transmissivity estimated from aquifer tests at a well located in Washington Borough is about 8,600 square feet per day. An aquifer test at a well located near the southwest border of Washington Borough was conducted to estimate transmissivity and the direction and magnitude of anisotropy. The estimated direction of maximum horizontal transmissivity near the second well is about 58? east of north and the magnitude is 7,600 square feet per day. The minimum horizontal transmissivity is 3,500 square feet per day and the ratio of anisotropy (maximum transmissivity to minimum transmissivity) is 2.2 to 1. Stream base-flow data indicate that Pohatcong Creek steadily gains flow, but

  3. Water-quality assessment of the Trinity River basin, Texas : ground-water quality of the Trinity, Carrizo-Wilcox, and Gulf Coast aquifers, February-August 1994

    USGS Publications Warehouse

    Reutter, David C.; Dunn, David D.

    2000-01-01

    Ground-water samples were collected from wells in the outcrops of the Trinity, Carrizo-Wilcox, and Gulf Coast aquifers during February-August 1994 to determine the quality of ground water in the three major aquifers in the Trinity River Basin study unit, Texas. These samples were collected and analyzed for selected properties, nutrients, major inorganic constituents, trace elements, pesticides, dissolved organic carbon, total phenols, methylene blue active substances, and volatile organic compounds as part of the U.S. Geological Survey National Water-Quality Assessment Program. Quality-control practices included the collection and analysis of blank, duplicate, and spiked samples. Samples were collected from 12 shallow wells (150 feet or less) and from 12 deep wells (greater than 150 feet) in the Trinity aquifer, 11 shallow wells and 12 deep wells in the Carrizo-Wilcox aquifer, and 14 shallow wells and 10 deep wells in the Gulf Coast aquifer. The three aquifers had similar water chemistries-calcium was the dominant cation and bicarbonate the dominant anion. Statistical tests relating well depths to concentrations of nutrients and major inorganic constituents indicated correlations between well depth and concentrations of ammonia nitrogen, nitrite plus nitrate nitrogen, bicarbonate, sodium, and dissolved solids in the Carrizo-Wilcox aquifer and between well depth and concentrations of sulfate in the Gulf Coast aquifer. The tests indicated no significant correlations for the Trinity aquifer. Concentrations of dissolved solids were larger than the secondary maximum contaminant level of 500 milligrams per liter established for drinking water by the U.S. Environmental Protection Agency in 12 wells in the Trinity aquifer, 4 wells in the Carrizo-Wilcox aquifer, and 6 wells in the Gulf Coast aquifer. Iron concentrations were larger than the secondary maximum contaminant level of 300 micrograms per liter in at least 3 samples from each aquifer, and manganese concentrations

  4. Modeling and Managing Regional Aquifers in Arid Countries

    NASA Astrophysics Data System (ADS)

    Schüth, C.; Rausch, R.

    2009-12-01

    Most of the regional aquifers in arid countries were recharged many thousand years ago when the climate was much wetter than today. Therefore, most of the groundwater stored in the aquifers is fossil water. The aquifers are in a state of constant depletion as recent groundwater recharge is much smaller than the outflow. A prerequisite for the smart management of such groundwater resources is a sound understanding of the aquifer system based on reliable data and robust simulation models. Mathematical groundwater models are one of the tools available that can consider a complex array of aquifer variables and allow these variables to interact with themselves. Exploring these interactions with a model can reveal how an aquifer behaves. Once a model is working properly, it can be used to make predictions for managing groundwater resources, such as predicting how groundwater levels might respond to increased pumping or drought, testing different management scenarios etc. Furthermore, groundwater models describing regional aquifers in arid regions must be considered to be in a transient state and consider the entire extent of the aquifer. The introduction of artificial boundaries is not possible and lead to wrong estimations. Within the modeling process the reduction and estimation of uncertainties is required, which leads to the “inverse problem” in groundwater modeling. Strategies for the reduction and estimation of uncertainties are needed. Problems are (1) the ill-posedness of parameter estimation, (2) that no unique solution may exist, and (3) that measurement errors make the results unreliable. Ways out are the reduction of degrees of freedom by introducing geological ‘a priori’ knowledge as well as the joint use of head, flow and/or concentration measurements, and the estimation of uncertainty. This concept is demonstrated by examples of model development for regional aquifers on the Arabian Peninsula, e.g. ‘a priori’ knowledge is introduced into the

  5. AUTOMATED WATER LEVEL MEASUREMENTS IN SMALL-DIAMETER AQUIFER TUBES

    SciTech Connect

    PETERSEN SW; EDRINGTON RS; MAHOOD RO; VANMIDDLESWORTH PE

    2011-01-14

    Groundwater contaminated with hexavalent chromium, strontium-90, and uranium discharges into the Columbia River along approximately 16 km (10 mi) of the shoreline. Various treatment systems have and will continue to be implemented to eliminate the impact of Hanford Site contamination to the river. To optimize the various remediation strategies, it is important to understand interactions between groundwater and the surface water of the Columbia River. An automated system to record water levels in aquifer sampling tubes installed in the hyporheic zone was designed and tested to (1) gain a more complete understanding of groundwater/river water interactions based on gaining and losing conditions ofthe Columbia River, (2) record and interpret data for consistent and defensible groundwater/surface water conceptual models that may be used to better predict subsurface contaminant fate and transport, and (3) evaluate the hydrodynamic influence of extraction wells in an expanded pump-and-treat system to optimize the treatment system. A system to measure water levels in small-diameter aquifer tubes was designed and tested in the laboratory and field. The system was configured to allow manual measurements to periodically calibrate the instrument and to permit aquifer tube sampling without removing the transducer tube. Manual measurements were collected with an e-tape designed and fabricated especially for this test. Results indicate that the transducer system accurately records groundwater levels in aquifer tubes. These data are being used to refine the conceptual and numeric models to better understand interactions in the hyporheic zone of the Columbia River and the adjacent river water and groundwater, and changes in hydrochemistry relative to groundwater flux as river water recharges the aquifer and then drains back out in response to changes in the river level.

  6. Hydrogeologic framework of the North Carolina Coastal Plain aquifer system

    USGS Publications Warehouse

    Winner, M.D.; Coble, R.W.

    1989-01-01

    The hydrogeologic framework of the North Carolina Coastal Plain aquifer system consists of ten aquifers separated by nine confining units. From top to bottom the aquifers are: the surficial aquifer, Yorktown aquifer, Pungo River aquifer, Castle Hayne aquifer, Beaufort aquifer, Peedee aquifer, Black Creek aquifer, upper Cape Fear aquifer, lower Cape Fear aquifer, and the Lower Cretaceous aquifer. The uppermost aquifer (the surficial aquifer in most places) is a water-table aquifer and the bottom of the system is underlain by crystalline bedrock. The sedimentary deposits forming the aquifers are of Holocene to Cretaceous age and are composed mostly of sand with lesser amounts of gravel and limestone. Confining units between aquifers are composed primarily of clay and silt. The thickness of the aquifers ranges from zero along the Fall Line to more than 10,000 feet at Cape Hatteras. Prominent structural features are the increasing easterly homoclinal dip of the sediments and the Cape Fear arch, the axis of which trends in a southeast direction. The stratigraphic continuity is determined from correlations of 161 geophysical logs along with data from drillers' and geologists' logs. Aquifers were defined by means of these logs plus water-level and water-quality data and evidence of the continuity of pumping effects. Eighteen hydrogeologic sections depict the correlation of these aquifers throughout the Coastal Plain.

  7. Conceptualization and simulation of the Edwards aquifer, San Antonio region, Texas

    USGS Publications Warehouse

    Lindgren, K.J.; Dutton, A.R.; Hovorka, S.D.; Worthington, S.R.H.; Painter, S.; ,

    2005-01-01

    Numerical ground-water flow models for the Edwards aquifer in the San Antonio region of Texas generally have been based on a diffuse-flow conceptualization. That is, although conduits likely are present, the assumption is that flow in the aquifer predominantly is through a network of small fractures and openings sufficiently numerous that the aquifer can be considered a porous-media continuum at the regional scale. Whether flow through large fractures and conduits or diffuse flow predominates in the Edwards aquifer at the regional scale is an open question. A new numerical ground-water-flow model (Edwards aquifer model) that incorporates important components of the latest information and an alternate conceptualization of the Edwards aquifer was developed. The conceptualization upon which the Edwards aquifer model is based emphasizes conduit development and conduit flow, and the model can be considered a test of one of two reasonable conceptualizations. The model incorporates conduits simulated as generally continuously connected, one-cell-wide (1,320 feet) zones with very large hydraulic-conductivity values (as much as 300,000 feet per day). The locations of the conduits are based on a number of factors, including major potentiometric-surface troughs in the aquifer, the presence of sinking streams, geochemical information, and geologic structures (for example, faults and grabens). The model includes both the San Antonio and Barton Springs segments of the Edwards aquifer in the San Antonio region, Texas, and was calibrated for steady-state (1939-46) and transient (1947-2000) conditions. Transient simulations were conducted using monthly recharge and pumpage (withdrawals) data. The predominantly conduit-flow conceptualization incorporated in the Edwards aquifer model yielded a reasonably good match between measured and simulated hydraulic heads in the confined part of the aquifer and between measured and simulated springflows. The simulated directions of flow in the

  8. Hydrogeology of the North Coast Limestone aquifer system of Puerto Rico

    USGS Publications Warehouse

    Rodríguez-Martínez, Jesús

    1995-01-01

    The North Coast Limestone aquifer system of Puerto Rico is composed of three regional hydrogeologic units: an upper aquifer that contains an underlying saltwater zone near the coast, a middle confining unit, and a lower aquifer. The upper aquifer is unconfined, except in coastal areas where it is locally confined by fine-grained surficial deposits. The upper aquifer is mostly absent in the Rio Piedras area of northeastern Puerto Rico. The confining unit is composed of calcareous claystone, marl, chalky and silicified limestone, and locally clayey fine-grained sandstone. Test hole data indicate that the confining unit is locally leaky in the San Juan metropolitan area. An artesian zone of limited areal extent exists within the middle confining unit, in the central part of the study area. The lower aquifer mostly contains ground water under confined conditions except in the outcrop areas, where it is unconfined. The lower aquifer is thickest and most transmissive in the north-central part of the study area. Water in the lower aquifer is fresh throughout much of the area, but is brackish in some areas near San Juan and Guaynabo. West of the Rio Grande de Arecibo, the extent of the lower aquifer is uncertain. Data are insufficient to determine whether or not the existing multiple water-bearing units in this area are an extension of the more productive lower aquifer in the Manati to Arecibo area. Zones of moderate permeability exist within small lenses of volcanic conglomerate and sandstone of the San Sebastian Formation, but in general this formation is not a productive aquifer. Transmissivity values for the upper aquifer range from 200 to more than 280,000 feet squared per day. The transmissivity values for the upper aquifer generally are highest in the area between the Rio de la Plata and Rio Grande de Arecibo, where transmissivity values have been reported to exceed 100,000 feet squared per day in six locations. Transmissivity estimates for the lower aquifer are

  9. Investigation of groundwater recirculation for the removal of RDX from the Pantex Plant perched aquifer

    SciTech Connect

    Woods, A.L.; Barnes, D.L.; Boles, K.M.; Charbeneau, R.J.; Black, S.; Rainwater, K.

    1998-07-01

    The Pantex Plant near Amarillo, Texas, is a US Department of Energy (DOE) facility that has been in operation since 1942. Past and present operations at Pantex include the creation of chemical high explosives components for nuclear weapons and assembly and disassembly of nuclear weapons. The Pantex Plant is underlain by the Ogallala aquifer, which in this area, consists of the main water-bearing unit and a perched water zone. These are separated by a fine-grained zone of low permeability. Multiple contaminant plumes containing high explosive (HE) compounds have been detected in the perched aquifer beneath the plant. The occurrence of these contaminants is the result of past waste disposal practices at the facility. RDX is an HE compound, which has been detected in the groundwater of the perched aquifer at significant concentrations. A pilot-scale, dual-phase extraction treatment system has been installed at one location at the plant, east of Zone 12, to test the effectiveness of such a system on the removal of these contaminants from the subsurface. A tracer test using a conservative tracer, bromide (Br), was conducted at the treatment site in 1996. In addition to the bromide, RDX and water elevations in the aquifer were monitored. Using data from the tracer test and other relevant data from the investigations at Pantex, flow and contaminant transport in the perched aquifer were simulated with groundwater models. The flow was modeled using MODFLOW and the transport of contaminants in the aqueous phase was modeled using MT3D. Modeling the perched aquifer had been conducted to characterize the flow in the perched aquifer; estimate RDX retardation in the perched aquifer; and evaluate the use of groundwater re-circulation to enhance the extraction of RDX from the perched aquifer.

  10. Major-ion and selected trace-metal chemistry of the Biscayne Aquifer, Southeast Florida

    USGS Publications Warehouse

    Radell, M.J.; Katz, B.G.

    1991-01-01

    The major-ion and selected trace-metal chemistry of the Biscayne aquifer was characterized as part of the Florida Ground-Water Quality Monitoring Network Program, a multiagency cooperative effort concerned with delineating baseline water quality for major aquifer systems in the State. The Biscayne aquifer is unconfined and serves as the sole source of drinking water for more than 3 million people in southeast Florida. The Biscayne aquifer consists of highly permeable interbedded limestone and sandstone of Pleistocene and Pliocene age underlying most of Dade and Broward Counties and parts of Palm Beach and Monroe Counties. The high permeability is largely caused by extensive carbonate dissolution. Water sampled from 189 wells tapping the Biscayne aquifer was predominantly a calcium bicarbonate type with some mixed types occurring in coastal areas and near major canals. Major - ion is areally uniform throughout the aquifer. According to nonparametric statistical tests of major ions and dissolved solids, the concentrations of calcium, sodium, bicarbonate, and dissolved solids increased significantly with well depth ( 0.05 significance level ), probably a result of less circulation at depth. Potassium and nitrate concentrations decreased significantly with depth. Although the source of recharge to the aquifer varies seasonally, there was no statistical difference in the concentration of major ions in pared water samples from 27 shallow wells collected during wet and dry seasons. Median concentrations for barium, chromium, copper, lead, and manganese were below maximum or secondary maximum contaminant levels set by the US Environmental Protection Agency. The median iron concentration only slightly exceeded the secondary maximum contaminant level. The concentration of barium was significantly related (0.05 significance level) to calcium and bicarbonate concentration. No distinct areal pattern or vertical distribution of the selected trace metals was evident in water from

  11. Hydrogeology and water-supply potential of the water-table aquifer on Dauphin Island, Alabama

    USGS Publications Warehouse

    Kidd, R.E.

    1988-01-01

    The water table aquifer on Dauphin Island, Alabama, consists of a thin veneer of Holocene sand and an underlying Pleistocene unit locally known as the Gulfport Formation. The aquifer is from 28 to 35 ft thick with a thick marine clay at its base. Water in the aquifer generally is low in chloride content except near the coast. Excessively high iron concentrations in groundwater were found locally. A two-dimensional finite-difference groundwater flow model of the water table aquifer on Dauphin Island was used in the steady-state mode to evaluate the flow system under steady-state conditions. Model input data were obtained primarily from 40 test wells, 2 aquifer tests, continuous recording of groundwater levels, and rainfall. The model was calibrated to the low water-table conditions of July 1985 and high water table conditions of April 1985. The model was also used to simulate pumpage from the aquifer under transient conditions with no rainfall. Patterns of computed head changes compared favorably to the natural recession of water levels for the periods of April to May 1985 and May to June 1985. Simulation of groundwater withdrawals in the transient model showed the feasibility of producing 0.6 million gallons/day from eight wells that tap the water table aquifer without inducing lateral seawater encroachment. (USGS)

  12. Thermal well-test method

    DOEpatents

    Tsang, Chin-Fu; Doughty, Christine A.

    1985-01-01

    A well-test method involving injection of hot (or cold) water into a groundwater aquifer, or injecting cold water into a geothermal reservoir. By making temperature measurements at various depths in one or more observation wells, certain properties of the aquifer are determined. These properties, not obtainable from conventional well test procedures, include the permeability anisotropy, and layering in the aquifer, and in-situ thermal properties. The temperature measurements at various depths are obtained from thermistors mounted in the observation wells.

  13. Investigation of artificial recharge of aquifers in Nebraska

    USGS Publications Warehouse

    Lichtler, William F.; Stannard, David I.; Kouma, Edwin

    1980-01-01

    Progressive declines of ground-water levels in some areas of Nebraska prompted this investigation into the technical feasibility of recharging aquifers through wells, impoundments, pits, and canals. Information gained from a literature search and from preliminary tests was used to design several artificial-recharge experiments in Nebraska from 1977 to 1979. In well experiments, 0.46 billion gallons of water from an aquifer recharged by the Platte River was transported by pipeline and injected through a well into a sand and gravel aquifer near Aurora. Recharge was at about 730 gallons per minute during tests of 6- and 8-months duration. No evidence of clogging of the aquifer due to chemical reactions, air entrainment, or bacteria was detected in either test. In the 6-month test, evidence of clogging due to fine sediment in the recharge water was detected; however, analysis of this test indicated that recharge could have continued for several years before rehabilitation would have become necessary. Results of the 8-month test confirmed results of the earlier test until casing failure in the supply well and subsequent sediment deposition in the recharge well caused rapid water-level rise in the recharge well. In surface-spreading experiments, maximum infiltration rates from 24-foot-diameter ring infiltrometers near Aurora and Tryon were 0.4 and 11 feet per day, respectively. Results indicate that large-scale surface spreading is feasible only where low-permeability layers are absent in the subsurface. Infiltration rates from reuse pits ranged from 0.01 to 1.6 feet per day, indicating highly variable subsurface permeability. Flow measurements in an irrigation canal near Farwell indicate an infiltration rate of 0.37 feet per day. (USGS)

  14. Sensitivity analysis of transport modeling in a fractured gneiss aquifer

    NASA Astrophysics Data System (ADS)

    Abdelaziz, Ramadan; Merkel, Broder J.

    2015-03-01

    Modeling solute transport in fractured aquifers is still challenging for scientists and engineers. Tracer tests are a powerful tool to investigate fractured aquifers with complex geometry and variable heterogeneity. This research focuses on obtaining hydraulic and transport parameters from an experimental site with several wells. At the site, a tracer test with NaCl was performed under natural gradient conditions. Observed concentrations of tracer test were used to calibrate a conservative solute transport model by inverse modeling based on UCODE2013, MODFLOW, and MT3DMS. In addition, several statistics are employed for sensitivity analysis. Sensitivity analysis results indicate that hydraulic conductivity and immobile porosity play important role in the late arrive for breakthrough curve. The results proved that the calibrated model fits well with the observed data set.

  15. 40 CFR 149.3 - Critical Aquifer Protection Areas.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 24 2012-07-01 2012-07-01 false Critical Aquifer Protection Areas. 149... (CONTINUED) SOLE SOURCE AQUIFERS Criteria for Identifying Critical Aquifer Protection Areas § 149.3 Critical Aquifer Protection Areas. A Critical Aquifer Protection Area is either: (a) All or part of an area...

  16. 40 CFR 149.3 - Critical Aquifer Protection Areas.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 24 2013-07-01 2013-07-01 false Critical Aquifer Protection Areas. 149... (CONTINUED) SOLE SOURCE AQUIFERS Criteria for Identifying Critical Aquifer Protection Areas § 149.3 Critical Aquifer Protection Areas. A Critical Aquifer Protection Area is either: (a) All or part of an area...

  17. 40 CFR 149.3 - Critical Aquifer Protection Areas.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 23 2014-07-01 2014-07-01 false Critical Aquifer Protection Areas. 149... (CONTINUED) SOLE SOURCE AQUIFERS Criteria for Identifying Critical Aquifer Protection Areas § 149.3 Critical Aquifer Protection Areas. A Critical Aquifer Protection Area is either: (a) All or part of an area...

  18. Capture zones for simple aquifers

    USGS Publications Warehouse

    McElwee, Carl D.

    1991-01-01

    Capture zones showing the area influenced by a well within a certain time are useful for both aquifer protection and cleanup. If hydrodynamic dispersion is neglected, a deterministic curve defines the capture zone. Analytical expressions for the capture zones can be derived for simple aquifers. However, the capture zone equations are transcendental and cannot be explicitly solved for the coordinates of the capture zone boundary. Fortunately, an iterative scheme allows the solution to proceed quickly and efficiently even on a modest personal computer. Three forms of the analytical solution must be used in an iterative scheme to cover the entire region of interest, after the extreme values of the x coordinate are determined by an iterative solution. The resulting solution is a discrete one, and usually 100-1000 intervals along the x-axis are necessary for a smooth definition of the capture zone. The presented program is written in FORTRAN and has been used in a variety of computing environments. No graphics capability is included with the program; it is assumed the user has access to a commercial package. The superposition of capture zones for multiple wells is expected to be satisfactory if the spacing is not too close. Because this program deals with simple aquifers, the results rarely will be the final word in a real application.

  19. A new aquifer assessment tool using reactive tracers

    NASA Astrophysics Data System (ADS)

    McKnight, D.; Smalley, A. L.; Banwart, S. A.; Lerner, D. N.; Thomson, N. R.; Thornton, S. F.; Wilson, R. D.

    2003-04-01

    A major obstacle to making informed decisions about trigger levels for restoration and choosing remediation options is that current Site Investigation (SI) practice fails to make optimal use of available SI techniques resulting in poor value for money in conceptual site models. Often it is simply too expensive to obtain the type of site data required to build the case for natural attenuation, even though this restoration option may be relatively cheaper than a pump-and-treat system. In particular, aquifer property measurement techniques for groundwater transport and reactions are too costly and this results in over-reliance on literature values or model assumptions. This results in overly uncertain predictions of in situ performance and therefore unnecessarily cautious risk assessment and costly remediation strategies. Therefore, cost-effective SI tools that have the capability of producing high quality characterisation data are required. The dipole flow test which circulates groundwater between isolated injection (source) and extraction (sink) chambers within a single borehole has been used successfully by others to delineate heterogeneous hydraulic properties in both highly permeable and fractured rock aquifers. We propose to extend this approach by adding a suite of reactive tracers into a dipole flow field to assess the geochemical properties and biodegradation potential of aquifers. If successful this will provide a method to ascertain site-specific parameters for use in appropriate reactive transport models. The initial phase of this project involves the construction of a laboratory-scale physical model of a dipole probe to investigate the utility of the dipole flow and reactive tracer test (DFRTT) as an aquifer assessment tool. This phase will also serve as the developmental stage between mathematical theory and a host of planned field trials. The development of the laboratory-scale DFRTT including initial scoping calculations, numerical simulation results

  20. Geochemical detection of carbon dioxide in dilute aquifers

    SciTech Connect

    Carroll, S; Hao, Y; Aines, R

    2009-03-27

    Carbon storage in deep saline reservoirs has the potential to lower the amount of CO{sub 2} emitted to the atmosphere and to mitigate global warming. Leakage back to the atmosphere through abandoned wells and along faults would reduce the efficiency of carbon storage, possibly leading to health and ecological hazards at the ground surface, and possibly impacting water quality of near-surface dilute aquifers. We use static equilibrium and reactive transport simulations to test the hypothesis that perturbations in water chemistry associated with a CO{sub 2} gas leak into dilute groundwater are important measures for the potential release of CO{sub 2} to the atmosphere. Simulation parameters are constrained by groundwater chemistry, flow, and lithology from the High Plains aquifer. The High Plains aquifer is used to represent a typical sedimentary aquifer overlying a deep CO{sub 2} storage reservoir. Specifically, we address the relationships between CO{sub 2} flux, groundwater flow, detection time and distance. The CO{sub 2} flux ranges from 10{sup 3} to 2 x 10{sup 6} t/yr (0.63 to 1250 t/m{sup 2}/yr) to assess chemical perturbations resulting from relatively small leaks that may compromise long-term storage, water quality, and surface ecology, and larger leaks characteristic of short-term well failure.

  1. A study of deep aquifers underlying coastal Orange County, California

    USGS Publications Warehouse

    Moreland, Joe A.; Singer, John A.

    1969-01-01

    zone, the depth to the base of aquifers containing fresh water ranges from 1,000 to 2,500 feet below mean sea level. The aquifers are composed of fine to medium sand with locally occurring beds of coarse sand and gravel. Permeability generally ranges from less than 50 gallons per day per square foot to 300 gallons per day per square foot. Pressure head increases with depth of the aquifer to as much as 40 feet above land surface near the base of fresh water. The water is of the sodium bicarbonate type, increasing in salinity with depth. Organic material imparts an amber color to the water, which becomes more distinct with depth. A test well, drilled to 926 feet and perforated from 784 to 884 feet, yielded 1,950 gallons per minute with about 90 feet of drawdown. The water is of the sodium bicarbonate type with dissolved solids of 225 mg/1. Additional studies are needed to evaluate the possibilities of subsidence due to pumping from the deep aquifers, to determine the vertical and horizontal permeabilities of confining beds, and to monitor the changes in water quality and water level.

  2. Estimating hydraulic properties of coastal aquifers using wave setup

    NASA Astrophysics Data System (ADS)

    Rotzoll, Kolja; El-Kadi, Aly I.

    2008-05-01

    SummaryWave setup is the elevated mean water-table at the coast associated with the momentum transfer of wave breaking, which occurs generally over several days. Groundwater responses to wave setup were observed as far as 5 km inland in central Maui, Hawaii. The analysis showed that at times of energetic swell events wave-driven water-table overheights dominate low-frequency groundwater fluctuations associated with barometric pressure effects. Matching peak frequencies at 1.7 × 10 -6 Hz and 3.7 × 10 -6 Hz were identified in setup and observed head using spectral decomposition. Similar to tides, the setup propagation through the aquifer shows exponentially decreasing amplitudes and linearly increasing time lags. Due to the longer periods of setup oscillations, the signal propagates deeper into the aquifer (˜10 km in central Maui) than diurnal tides (5 km) and can therefore provide information on greater length scales. Hydraulic diffusivity was estimated based on the setup propagation. An effective diffusivity of 2.3 × 10 7 m 2/d is consistent with aquifer parameters based on aquifer tests and tides. A one-dimensional numerical model supports the results of the analytical solution and strengthens the suitability to estimate hydraulic parameters from setup propagation. The methodology is expected to be beneficial to high-permeability coastal environments, such as on volcanic islands and atolls.

  3. The Tuscaloosa Aquifer system in Mississippi

    USGS Publications Warehouse

    Boswell, E.H.

    1978-01-01

    A three-sheet map report describes the Tuscaloosa aquifer system in Mississippi. The Tuscaloosa aquifer system, of Cretaceous age , is in the interconnected irregular sand and gravel beds in the Coker and Gordo Formations. The aquifer contains freshwater in an area of about 9,000 sq mi in northeastern Mississippi. Water produced from the aquifer by about 90 water systems and numerous industries in 1975 averaged about 47 Mgal/d. Regional water level declines have averaged less than two feet per year and the aquifer has a large potential for future development. The aquifer is used in some areas where the dissolved-solids concentration is more than 500 mg/L and where wells exceed 2,000 ft in depth. The most common problems in water supplies are excessive chloride and iron. (Woodard-USGS)

  4. Hydrogeologic Appraisal of the Valley-Fill Aquifer in the Port Jervis Trough, Sullivan and Ulster Counties, New York

    USGS Publications Warehouse

    Reynolds, Richard J.

    2007-01-01

    The nature and extent of valley-fill aquifers in the Port Jervis Trough was evaluated for a 16 mile section of this valley from the Orange-Sullivan County line near Westbrookville to the village of Napanoch in Ulster County as part of the U.S. Geological Survey's Detailed Aquifer Mapping Program in New York State. The principal aquifer in the Port Jervis Trough is a 50 feet thick outwash aquifer that extends from the Phillipsport Moraine near Summitville, southward through the study area to Port Jervis, N.Y. Previous studies had estimated as much as 500 feet of saturated drift in parts of the Trough, but new well data show that much of the valley fill consists of fine-grained lacustrine sediments. Drillers' logs show that the outwash aquifer south of Summitville is underlain by as much as 275 feet of lacustrine silt and clay. North of the Phillipsport Moraine, three large glaciolacustrine deltas that were built into Glacial Lake Wawarsing provide some local and discontinuous confined aquifers through their coarser bottomset beds. Elsewhere in the Trough, collapsed and buried portions of kame deltas and terraces provide local confined aquifers. The outwash aquifer appears to be very transmissive, as evidenced by the high specific capacity of 130 gallons per minute per foot [(gal/min)/ft] of a commercial test well screened in the aquifer.

  5. Preliminary assessment of the ground-water resources of the alluvial aquifer, White River valley, Rio Blanco County, Colorado

    USGS Publications Warehouse

    Van Liew, W. P.; Gesink, M.L.

    1985-01-01

    A preliminary study of the alluvial aquifer in the White River Valley was conducted to assess aquifer extent and the occurrence , availability, and chemical quality of water in the aquifer. The aquifer in the study area underlies 35 square miles. Aquifer width ranges from 0.1 to 1.5 miles and averages 0.5 miles. Saturated thickness ranges from zero to more than 140 feet and averages 22 feet. The aquifer is unconfined except west of the Grand Hogback, where artesian conditions were observed at several locations. Well yields usually are less than 25 gallons per minute. At the Meeker municipal well field in Agency Park, wells reportedly could yield more than 1,000 gallons per minute each. Based on nine aquifer tests, transmissivity ranges from 860 to 93,000 feet squared per day, and hydraulic conductivity ranges from 70 to 1,550 feet per day. The estimated total volume of water in storage in the aquifer in the study area is 103,000 acre-feet. Groundwater type in the eastern part of the study area is calcium bicarbonate; to the west, water type is sodium sulfate. Water in the aquifer is classified as very hard throughout the study area. Specific conductance generally increases from east to west. (USGS)

  6. A digital-computer model for estimating hydrologic changes in the aquifer system in Dane County, Wisconsin

    USGS Publications Warehouse

    McLeod, R.S.

    1975-01-01

    The extensive use of ground water for water supply within Dane County has resulted in the need for an appraisal of the area's ground-water resources. Water-resources planners and other water-oriented groups have expressed concern over ground-water level declines and reductions in streamflow that are occurring as a result of heavy pumping. Digital-computer modeling techniques were used to estimate hydrologic changes in the aquifer system that would be caused by continued development. The system was modeled as a two-aquifer system consisting of a confined sandstone aquifer overlain by a leaky unconfined aquifer and underlain by impermeable bedrock. The physical properties of the aquifer system needed for the model were approximated using aquifer-test data and well-log data and by matching observed hydrologic changes in the system with corresponding changes computed by the model. Computed hydrologic changes do not represent a serious depletion of the available ground-water supply for the foreseeable future. Maximum added regional declines in ground-water levels (drawdowns) from 1970 to 1990 were computed to be approximately 10 feet (3 metres) in the unconfined aquifer and approximately 40 feet (12 metres) in the confined aquifer. It is computed that for the same period the average annual streamflow from the upper Yahara River basin would be reduced by approximately 29 cubic feet per second (0.82 cubic metre per second). These changes are computed based on estimated development trends for the confined sandstone aquifer.

  7. Identification of the microbes mediating Fe reduction in a deep saline aquifer and their influence during managed aquifer recharge.

    PubMed

    Ko, Myoung-Soo; Cho, Kyungjin; Jeong, Dawoon; Lee, Seunghak

    2016-03-01

    In this study, indigenous microbes enabling Fe reduction under saline groundwater conditions were identified, and their potential contribution to Fe release from aquifer sediments during managed aquifer recharge (MAR) was evaluated. Sediment and groundwater samples were collected from a MAR feasibility test site in Korea, where adjacent river water will be injected into the confined aquifer. The residual groundwater had a high salinity over 26.0 psu, as well as strong reducing conditions (dissolved oxygen, DO<2.0mg/L; oxidation-reduction potential, ORP<-100 mV) with high Fe(2+) concentrations. The indigenous microbes that mediate the reduction of Fe-minerals in this deep saline aquifer were found to be Citrobacter sp. However, column experiments to simulate field operation scenarios indicated that additional Fe release would be limited during MAR, as the dominant microbial community in the sediment would shift from Citrobacter sp. to Pseudomonas sp. and Limnohabitans sp. as river water injection alters the pore water chemistry.

  8. Identification of the microbes mediating Fe reduction in a deep saline aquifer and their influence during managed aquifer recharge.

    PubMed

    Ko, Myoung-Soo; Cho, Kyungjin; Jeong, Dawoon; Lee, Seunghak

    2016-03-01

    In this study, indigenous microbes enabling Fe reduction under saline groundwater conditions were identified, and their potential contribution to Fe release from aquifer sediments during managed aquifer recharge (MAR) was evaluated. Sediment and groundwater samples were collected from a MAR feasibility test site in Korea, where adjacent river water will be injected into the confined aquifer. The residual groundwater had a high salinity over 26.0 psu, as well as strong reducing conditions (dissolved oxygen, DO<2.0mg/L; oxidation-reduction potential, ORP<-100 mV) with high Fe(2+) concentrations. The indigenous microbes that mediate the reduction of Fe-minerals in this deep saline aquifer were found to be Citrobacter sp. However, column experiments to simulate field operation scenarios indicated that additional Fe release would be limited during MAR, as the dominant microbial community in the sediment would shift from Citrobacter sp. to Pseudomonas sp. and Limnohabitans sp. as river water injection alters the pore water chemistry. PMID:26760269

  9. Framework for Evaluating Water Quality of the New England Crystalline Rock Aquifers

    USGS Publications Warehouse

    Harte, Philip T.; Robinson,, Gilpin R.; Ayotte, Joseph D.; Flanagan, Sarah M.

    2008-01-01

    Little information exists on regional ground-water-quality patterns for the New England crystalline rock aquifers (NECRA). A systematic approach to facilitate regional evaluation is needed for several reasons. First, the NECRA are vulnerable to anthropogenic and natural contaminants such as methyl tert-butyl ether (MTBE), arsenic, and radon gas. Second, the physical characteristics of the aquifers, termed 'intrinsic susceptibility', can lead to variable and degraded water quality. A framework approach for characterizing the aquifer region into areas of similar hydrogeology is described in this report and is based on hypothesized relevant physical features and chemical conditions (collectively termed 'variables') that affect regional patterns of ground-water quality. A framework for comparison of water quality across the NECRA consists of a group of spatial variables related to aquifer properties, hydrologic conditions, and contaminant sources. These spatial variables are grouped under four general categories (features) that can be mapped across the aquifers: (1) geologic, (2) hydrophysiographic, (3) land-use land-cover, and (4) geochemical. On a regional scale, these variables represent indicators of natural and anthropogenic sources of contaminants, as well as generalized physical and chemical characteristics of the aquifer system that influence ground-water chemistry and flow. These variables can be used in varying combinations (depending on the contaminant) to categorize the aquifer into areas of similar hydrogeologic characteristics to evaluate variation in regional water quality through statistical testing.

  10. Recovery of injected freshwater from a brackish aquifer with a multiwell system.

    PubMed

    Miotliński, Konrad; Dillon, Peter J; Pavelic, Paul; Barry, Karen; Kremer, Sarah

    2014-01-01

    Herein we propose a multiple injection and recovery well system strategically operated for freshwater storage in a brackish aquifer. With the system we call aquifer storage transfer and recovery (ASTR) by using four injection and two production wells, we are capable of achieving both high recovery efficiency of injected freshwater and attenuation of contaminants through adequately long residence times and travel distances within the aquifer. The usual aquifer storage and recovery (ASR) scheme, in which a single well is used for injection and recovery, does not warrant consistent treatment of injected water due to the shorter minimum residence times and travel distances. We tested the design and operation of the system over 3 years in a layered heterogeneous limestone aquifer in Salisbury, South Australia. We demonstrate how a combination of detailed aquifer characterization and solute transport modeling can be used to maintain acceptable salinity of recovered water for its intended use along with natural treatment of recharge water. ASTR can be used to reduce treatment costs and take advantage of aquifers with impaired water quality that might locally not be otherwise beneficially used.

  11. Sole Source Aquifer designation: petitioner guidance

    SciTech Connect

    Braem, L.

    1987-02-01

    The purpose of the guidance is to aid potential Sole Source Aquifer (SSA) petitioners to prepare and submit Sole Source Aquifer designation petitions to the Environmental Protection Agency. The Sole Source Aquifer program was established under the 1974 Safe Drinking Water Act, to protect principal or sole sources of drinking water for an area from contamination. The guidance presents an overview of the designation process, petition preparation, and how and where to submit petition information. Also included is general information about the Sole Source Aquifer program.

  12. Hydrology of the surficial aquifer in the Floyd River Basin, Iowa

    USGS Publications Warehouse

    Wahl, K.D.; Meyer, M.J.; Karsten, R.A.

    1982-01-01

    An aquifer test conducted in the surficial aquifer where it is about 25 feet thick and is confined by an overlying low permeability bed Indicated an average hydraulic conductivity of 383 feet per day and a storage coefficient of 0.0001. The well was pumped at 650 gallons per minute for 43 hours. An observation well about 70 feet from the pumping well had a maximum drawdown of about 10 feet.

  13. An evaluation of aquifer intercommunication between the unconfined and Rattlesnake Ridge aquifers on the Hanford Site

    SciTech Connect

    Jensen, E.J.

    1987-10-01

    During 1986, Pacific Northwest Laboratory conducted a study of a portion of the Rattlesnake Ridge aquifer (confined aquifer) that lies beneath the B Pond - Gable Mountain Pond area of the Hanford Site. The purpose was to determine the extent of intercommunication between the unconfined aquifer and the uppermost regionally extensive confined aquifer, referred to as the Rattlesnake Ridge aquifer. Hydraulic head data and chemical data were collected from the ground water in the study area during December 1986. The hydraulic head data were used to determine the effects caused by water discharged to the ground from B Pond on both the water table of the unconfined aquifer and the potentiometric surface of the confined aquifer. The chemical data were collected to determine the extent of chemical constituents migrating from the unconfined aquifer to the confined aquifer. Analysis of chemical constituents in the Rattlesnake Ridge aquifer demonstrated that communication between the unconfined and confined aquifers had occurred. However, the levels of contaminants found in the Rattlesnake Ridge aquifer during this study were below the DOE Derived Concentration Guides.

  14. Extended access to methamphetamine self-administration up-regulates dopamine transporter levels 72 hours after withdrawal in rats.

    PubMed

    D'Arcy, Christina; Luevano, Joe E; Miranda-Arango, Manuel; Pipkin, Joseph A; Jackson, Jonathan A; Castañeda, Eddie; Gosselink, Kristin L; O'Dell, Laura E

    2016-01-01

    Previous studies have demonstrated that there are persistent changes in dopamine systems following withdrawal from methamphetamine (METH). This study examined changes in striatal dopamine transporter (DAT), tyrosine hydroxylase (TH) and dopamine receptor 2 (D2) 72 h after withdrawal from METH intravenous self- administration (IVSA). Rats were given limited (1h) or extended (6h) access to METH IVSA (0.05 mg/kg/0.1 ml infusion) for 22 days. Controls did not receive METH IVSA. The rats given extended access to IVSA displayed higher METH intake during the first hour of drug access compared to rats given limited access. Extended access to METH also produced a concomitant increase in striatal DAT levels relative to drug-naïve controls. There were no changes in TH or D2 levels across groups. Previous studies have reported a decrease in striatal DAT levels during protracted periods (>7 days) of withdrawal from METH IVSA. This study extends previous work by showing an increase in striatal DAT protein expression during an earlier time point of withdrawal from this drug. These results are an important step toward understanding the dynamic changes in dopamine systems that occur during different time points of withdrawal from METH IVSA.

  15. Measurement of Cytokines and Adhesion Molecules in the First 72 Hours after Severe Trauma: Association with Severity and Outcome

    PubMed Central

    Sousa, António; Raposo, Frederico; Fonseca, Sara; Valente, Luís; Duarte, Filipe; Gonçalves, Moura; Tuna, Diana; Paiva, José-Artur

    2015-01-01

    Introduction. Severity and outcome assessments are crucial in trauma. Our aim was to describe the role of a group of cytokines (TNFα, IL-6, IL-10, and HMGB-1) and ICAM-1 as severity and outcome assessment tools and their kinetics in the first 72 h after severe trauma. Materials and Methods. Authors designed a prospective cohort study of severe polytrauma patients (ISS > 15) in a level 1 Trauma Centre. Cytokines and ICAM-1 levels and Th1/Th2 ratios were assessed at admission, 24, 48, and 72 h. SIRS, SIRS with hypoperfusion, and shock were identified. Outcomes considered were ICU admission, ARDS, MODS, and death. Results. Ninety-nine patients were enrolled (median ISS: 29 and age 31). There was an early release of pro- and anti-inflammatory mediators with higher values at admission (except for ICAM-1). On admission, IL-6 was associated with ISS, IL-10 with SIRS with hypoperfusion, and HMGB-1 with shock. Several cytokines were associated with outcomes, especially IL-6 and IL-10 at 72 h with MODS and death. Low TNFα/IL-10 and IL-6/IL-10 ratios at 24 and 72 h were associated with MODS and death. Conclusions. Pro- and anti-inflammatory responses occur simultaneously and earlier after injury. Cytokines may be useful for outcome assessment, especially IL-6 and IL-10. Low Th1/Th2 ratio at 24 to 72 h is associated with MODS and death. PMID:25861153

  16. Dynamic Changes of Pulmonary Arterial Pressure and Ductus Arteriosus in Human Newborns From Birth to 72 Hours of Age

    PubMed Central

    Kang, Chunmiao; Zhao, Enfa; Zhou, Yinghua; Zhao, Huayun; Liu, Yunyao; Gao, Ningning; Huang, Xiaoxin; Liu, Baomin

    2016-01-01

    Abstract Normal pulmonary artery pressure and pulmonary hypertension assessment of newborns is rarely reported. The aim of the study is to explore dynamic changes of pulmonary arterial pressure and ductus arteriosus in human newborns from birth to 72 h of age with echocardiography. A total of 76 cases of normal newborns were prospectively detected by echocardiography after birth of 2 h, 6 h, 12 h, 24 h, 48 h, and 72 h, respectively. Ductus arteriosus diameter, blood shunt direction, blood flow velocity, and pressure gradient were recorded. The brachial artery blood pressure were measured to estimate the pulmonary artery systolic pressure (PASP) and pulmonary artery diastolic pressure (PADP) using patent ductus arteriosus pressure gradient method. The mean pulmonary artery pressure (PAMP) were calculated by equation of PAMP = PADP + 1/3(PASP-PADP). (1) There were 76 cases of normal newborns. Among them, 29 cases (38%) ductus arteriosus closed within 24 h, 59 cases (78%) closed within 48 h, 72 cases (95%) closed within 72 h, and 4 cases (5%) ductus arteriosus not closed within 72 h. (2) The ductus arteriosus diameter of 2 h, 6 h, 12 h, 24 h, 48 h, and 72 h after birth was 4.60 ± 0.59 mm, 3.37 ± 0.59 mm, 2.47 ± 0.49 mm, 1.89 ± 0.41 mm, 1.61 ± 0.35 mm, and 1.20 ± 0.24 mm, respectively. Compared all of the ductus arteriosus diameter of the above time periods, there were statistically differences with P < 0.05, respectively. (3) The mean PASP in 2 h, 6 h, 12 h, 24 h, 48 h, 72 h after birth were 76.58 ± 7.28 mm Hg, 65.53 ± 9.25mm Hg, 52.51 ± 9.07 mm Hg, 43.83 ± 7.90 mm Hg, 38.07 ± 8.26 mm Hg, and 36 ± 6.48 mm Hg, respectively. The PADP of the above time period were 37.88 ± 5.56 mm Hg, 29.93 ± 7.91 mm Hg, 23.43 ± 7.37 mm Hg, 19.70 ± 8.51 mm Hg, 13.85 ± 5.58 mm Hg, 13.25 ± 6.18 mm Hg, respectively. The PAMP of the above time period were 63.41 ± 7.03 mm Hg, 51.78 ± 9.82 mm Hg, 40.94 ± 9.32 mm Hg, 34.39 ± 9.89 mm Hg, 26.23 ± 7.49 mm Hg, 25.25 ± 8.29 mm Hg, respectively. There were statistically differences with P < 0.05 between each time periods of PASP, PADP, and PAMP. (4) The upper 95% limit reference range of PASP of normal newborns of 72 h after birth were 39.97 mm Hg. (1) Normal newborns ductus arteriosus diameter gradually decreased after birth, and 95% of them spontaneous closed within 24 to 72 h. (2) Normal newborns pulmonary artery pressure showed a gradually decline after birth, the upper 95% limit reference range for PASP measured in normal newborns <72 h of age was 39.97 mm Hg. Therefore, the diagnostic criteria of newborns pulmonary hypertension may be >40.00 mm Hg according to our limited study. PMID:26817918

  17. Hydrogeologic characteristics of the alluvial aquifer and adjacent deposits of the Fountain Creek valley, El Paso County, Colorado

    USGS Publications Warehouse

    Radell, Mary Jo; Lewis, Michael E.; Watts, Kenneth R.

    1994-01-01

    The alluvial aquifer in Fountain Creek Valley between Colorado Springs and Widefield is the source for several public-supply systems. Because of the importance of this aquifer, defining aquifer boundaries, areas where underflow occurs, and where Fountain Creek is hydraulically connected to the aquifer will greatly add to the understanding of the alluvial aquifer and management of the public- supply systems. Bedrock altitude, water-table altitude for October 1991, saturated thickness for October 1991, selected hydrogeologic sections in the alluvial aquifer and adjacent deposits of the Fountain Creek Valley, and estimated underflow rates are mapped or tabulated for the area between Colorado Springs and Widefield, Colorado. Results from test drilling indicate that the bedrock surface is highly irregular and that several ridges and buried channels exist in the study area. These features affect the direction of ground-water flow on a local scale. In places, a shale ridge prevents exchange of water between Fountain Creek and the aquifer. Generally, ground water flowed toward Fountain Creek during the study (June 1991 to September 1992) in response to relatively high hydraulic heads in the aquifer and the steep gradients on the boundaries of the study area. Water levels, which were measured monthly, varied little during the study, except in areas near pumping wells or adjacent to Fountain Creek. Hydraulic-conductivity values, estimated from 30 bail tests in wells completed in the alluvial aquifer, were used to determine underflow across the saturated boundaries of the alluvial aquifer. Estimated hydraulic-conductivity values range from 1 to about 1,300 feet per day; the larger values occur in the buried channel of the alluvial aquifer and the smaller values occur near the boundaries of the saturated alluvium. Estimated underflow into the study area exceeded underflow out of the study area by about 10 times. Gain-loss investigations along Fountain Creek indicated that the

  18. Three-dimensional flow in the storative semiconfining layers of a leaky aquifer

    USGS Publications Warehouse

    Sepulveda, N.

    2008-01-01

    An analytical solution for three-dimensional (3D) flow in the storative semiconfining layers of a leaky aquifer fully penetrated by a production well is developed in this article to provide a method from which accurate hydraulic parameters in the semiconfining layers can be derived from aquifer test data. The analysis of synthetic aquifer test data with the 3D analytical solution in the semiconfining layers provided more accurate optimal hydraulic parameters than those derived using the available quasi-two-dimensional (2D) solution. Differences between the 3D and 2D flow solutions in the semiconfining layers become larger when a no flow boundary condition is imposed at either at the top of the upper semiconfining layer or at the bottom of the lower semiconfining layer or when the hydraulic conductivity ratio of the semiconfining layer to the aquifer is larger than 0.001. In addition, differences between the 3D and 2D flow solutions in the semiconfining layers are illustrated when the thickness ratio of the semiconfining layer to the aquifer is changed. Analysis of water level data from two hypothetical and one real aquifer test showed that the 3D solution in the semiconfining layers provides lower correlation coefficients among hydraulic parameters than the 2D solution. ?? 2007 National Ground Water Association.

  19. Mobility and sorption of bis-2-chloroethyl ether in an aquifer material.

    PubMed

    Bednar, A J; Kirgan, R A; Karn, R A; Donovan, B; Mohn, M F; Sirkis, D M

    2009-09-15

    Active treatment of BCEE (bis-2-chloroethyl ether) is being currently performed in the on-site Cohansey Aquifer at the Lipari Superfund Site. Remediation of BCEE in the underlying Kirkwood aquifer is being considered, necessitating investigations of BCEE geochemistry in aquifer material from the site. It is currently unknown to what extent BCEE is present in the dissolved, sorbed, or free-product phase in the Kirkwood Sand aquifer material. A series of partition coefficient sorption, column leach, and column loading tests were conducted to determine BCEE sorption to, and mobility in, the Kirkwood Sand aquifer material. The leach studies indicated that up to 50% of BCEE spiked (as free-phase product) onto two aquifer material column designs could be leached in approximately 18h, due to the high aqueous solubility of BCEE. Dissolved BCEE concentrations then began to plateau as sorption reactions hindered further leaching, resulting in up to 80% removal after 48h. Column loading and batch sorption experiments suggest that BCEE mobility is limited by sorption rather than solubility factors. Tracer tests in both column loading and batch sorption tests indicate sorption hinders leaching of BCEE from the Kirkwood Sand material.

  20. Hydrophobic organic contaminant transport property heterogeneity in the Borden Aquifer

    NASA Astrophysics Data System (ADS)

    Allen-King, Richelle M.; Kalinovich, Indra; Dominic, David F.; Wang, Guohui; Polmanteer, Reid; Divine, Dana

    2015-03-01

    We determined that the spatial heterogeneity in aquifer properties governing the reactive transport of volatile organic contaminants is defined by the arrangement of lithofacies. We measured permeability (k) and perchloroethene sorption distribution coefficient (Kd) for lithofacies that we delineated for samples from the Canadian Forces Base Borden Aquifer. We compiled existing data and collected 57 new cores to characterize a 30 m section of the aquifer near the test location of Mackay et al. (1986). The k and Kd were measured for samples taken at six elevations from all cores to create a data set consisting of nearly 400 colocated measurements. Through analysis of variance (corrected for multiple comparisons), we determined that the 12 originally mapped lithofacies could be grouped into five relatively distinct chemohydrofacies that capture the variability of both transport properties. The mean of ln k by lithofacies was related to the grain size and the variance was relatively consistent. In contrast, both the mean and variance of ln Kd were greater for more poorly sorted lithofacies, which were also typically more coarse-grained. Half of the aquifer sorption capacity occurred in the three highest-sorbing lithofacies but comprised only 20% of its volume. The model of the aquifer that emerged is that of discontinuous scour-fill deposits of medium sand, generally characterized by greater Kd and k, within laterally extensive fine-grained to very fine-grained sands of lower Kd and k. Our findings demonstrate the importance of considering source rock composition, transport, and deposition processes when constructing conceptual models of chemohydrofacies.

  1. Lateral groundwater inflows into alluvial aquifers of main alpine valleys

    NASA Astrophysics Data System (ADS)

    Burger, Ulrich

    2015-04-01

    In alpine regions the topography is mainly characterised by deep incised valleys, mountain slopes and ridges. Usually the main valleys contain aquifers in alluvial soft rock. Lateral these aquifers are confined by mountainous hard rock slopes covered by heterogeneous sediments with different thickness. The slopes can be incised by lateral valleys. Numerical models for the main alluvial aquifers ask for lateral hydrogeological boundaries. Usually no flow boundaries or Constant head Boundaries are used, even if the lateral inflows to the main aquifers are rarely known. In this example a data set for a detailed investigated and monitored area is studied to give an answer on the location and the quantification of these lateral subsurface inflows. The study area is a typical main alpine valley with a thick alluvial aquifer (appr. 120m thick), lateral confined by granite, covered at the base of the steep slopes by quaternary sediments (Burger at al. 2012). The study consists of several steps 1.) Analytical calculation of the inflows on the base of investigated and monitored 2d profiles along fault zones (Perello et al 2013) which pinch out in the main valley 2.) Analytical models along typical W-dipping slopes with monitored slope springs 3.) Evaluating temperature and electrical conductivity profiles measured in approx. 30 groundwater wells in the alluvial aquifers and along the slopes to locate main lateral subsurface inflows 4.) Output of a regional model used for the hydrogeological back analyses of the excavation of a tunnel (Baietto et al. 2014) 5.) Output of a local numerical model calibrated with a monitoring dataset and results of a pumping test of big scale (450l/s for 10days) Results of these analyses are shown to locate and quantify the lateral groundwater inflows in the main alluvial aquifer. References Baietto A., Burger U., Perello P. (2014): Hydrogeological modelling applications in tunnel excavations: examples from tunnel excavations in granitic rocks

  2. Geothermal development of the Madison group aquifer: a case study

    SciTech Connect

    Martinez, J.A.

    1981-01-01

    A geothermal well has been drilled at the St. Mary's Hospital in Pierre, South Dakota. The well is 2176 feet deep and artesian flows 375 gpm at 106/sup 0/F. The well is producing fluids from the Mississippian Madison Group, a sequence of carbonate rocks deposited over several western states. The project was funded to demonstrate the goethermal potential of this widespread aquifer. This case study describes the development of the project through geology, drilling, stimulation, and testing.

  3. Unusual Recharge Processes near Arroyos of the Rio Grande Aquifer, El Paso/Juarez Area

    NASA Astrophysics Data System (ADS)

    Merino, M.; Hibbs, B. J.; Hogan, J.; Eastoe, C. J.; Druhan, J.

    2005-12-01

    The twin-cities of El Paso and Juarez share the water resources of the Hueco Bolson aquifer and overlying Rio Grande aquifer. Both aquifers span the international border between Mexico and the United States. Salinity in the Rio Grande aquifer varies widely, some parts of the shallow aquifer containing less than 1,000 mg/L total dissolved solids (TDS), other parts of the aquifer exceeding 5,000 mg/L TDS. One sizable part of the "Lower Valley" area, approximately 45 km below El Paso contains very dilute water near the outer edge of the floodplain. Historically it had been thought that the dilute waters in this location were derived from recharge from arroyos that drained proximal parts of the Hueco Bolson. Instead, our hydrogen and oxygen isotope data and carbon-14 data indicate that these dilute waters were derived from pre-dam infiltration of the Rio Grande. Relatively light and slightly evaporated pre-dam waters (-11.5 del O18) at the arroyos are also relatively young (60 to 90 percent modern carbon), tagging them as runoff waters from pre-dam snowmelt in Colorado. These isotopically light waters are found up to 110 meters beneath land surface. Prior to Rio Grande rectification and channelization of the mid-1930's, the Rio Grande flowed near the outer edge of the floodplain where these pre-dam, dilute waters are found at depth. Review of predevelopment drill stem tests indicated a permeable zone about 150 to 230 meters deep that had a lower hydraulic head than the overlying Rio Grande aquifer. The permeable zone acted as a predevelopment sink for flow that induced recharge from the Rio Grande and Rio Grande aquifer. Thus, we can account for local predevelopment recharge of the Rio Grande aquifer from infiltration of dilute water from the Rio Grande prior to the historic era of channel rectification, and not from recharge from flanking arroyos as had been postulated by previous researchers.

  4. Hydrochemistry and hydrogeologic conditions within the Hanford Site upper basalt confined aquifer system

    SciTech Connect

    Spane, F.A. Jr.; Webber, W.D.

    1995-09-01

    As part of the Hanford Site Ground-Water Surveillance Project, Flow System Characterization Task. Pacific Northwest Laboratory examines the potential for offsite migration of contamination within the upper basalt confined aquifer system for the US Department of Energy (DOE). As part of this activity, groundwater samples were collected over the past 2 years from selected wells completed in the upper Saddle Mountains Basalt. The hydrochemical and isotopic information obtained from these groundwater samples provides hydrologic information concerning the aquifer-flow system. Ideally, when combined with other hydrologic property information, hydrochemical and isotopic data can be used to evaluate the origin and source of groundwater, areal groundwater-flow patterns, residence and groundwater travel time, rock/groundwater reactions, and aquifer intercommunication for the upper basalt confined aquifer system. This report presents the first comprehensive Hanford Site-wide summary of hydrochemical properties for the upper basalt confined aquifer system. This report provides the hydrogeologic characteristics (Section 2.0) and hydrochemical properties (Section 3.0) for groundwater within this system. A detailed description of the range of the identified hydrochemical parameter subgroups for groundwater in the upper basalt confined aquifer system is also presented in Section 3.0. Evidence that is indicative of aquifer contamination/aquifer intercommunication and an assessment of the potential for offsite migration of contaminants in groundwater within the upper basalt aquifer is provided in Section 4.0. The references cited throughout the report are given in Section 5.0. Tables that summarize groundwater sample analysis results for individual test interval/well sites are included in the Appendix.

  5. Hydrostratigraphic modeling of a complex, glacial-drift aquifer system for importation into MODFLOW

    USGS Publications Warehouse

    Herzog, B.L.; Larson, D.R.; Abert, C.C.; Wilson, S.D.; Roadcap, G.S.

    2003-01-01

    Deposition from at least three episodes of glaciation left a complex glacial-drift aquifer system in central Illinois. The deepest and largest of these aquifers, the Sankoty-Mahomet Aquifer, occupies the lower part of a buried bedrock valley and supplies water to communities throughout central Illinois. Thin, discontinuous aquifers are present within glacial drift overlying the Sankoty-Mahomet Aquifer. This study was commissioned by local governments to identify possible areas where a regional water supply could be obtained from the aquifer with minimal adverse impacts on existing users. Geologic information from more than 2200 existing water well logs was supplemented with new data from 28 test borings, water level measurements in 430 wells, and 35 km of surface geophysical profiles. A three-dimensional (3-D) hydrostratigraphic model was developed using a contouring software package, a geographic information system (GIS), and the 3-D geologic modeling package, EarthVision??. The hydrostratigraphy of the glacial-drift sequence was depicted as seven uneven and discontinuous layers, which could be viewed from an infinite number of horizontal and vertical slices and as solid models of any layer. Several iterations were required before the 3-D model presented a reasonable depiction of the aquifer system. Layers from the resultant hydrostratigraphic model were imported into MODFLOW, where they were modified into continuous layers. This approach of developing a 3-D hydrostratigraphic model can be applied to other areas where complex aquifer systems are to be modeled and is also useful in helping lay audiences visualize aquifer systems.

  6. Geohydrology and water quality of the Roubidoux Aquifer, northeastern Oklahoma

    USGS Publications Warehouse

    Christenson, S.C.; Parkhurst, D.L.; Fairchild, R.W.

    1990-01-01

    The Roubidoux aquifer is an important source of freshwater for public supplies, commerce, industry, and rural water districts in northeastern Oklahoma. Ground-water withdrawals from the aquifer in 1981 were estimated to be 4.8 million gallons per day, of which about 90 percent was withdrawn in Ottawa County. Wells drilled at the beginning of the 20th century originally flowed at the land surface, but in 1981 water levels ranged from 22 to 471 feet below land surface. A large cone of depression has formed as a result of ground water withdrawals near Miami. Wells completed in the Roubidoux aquifer have yields that range from about 100 to more than 1,000 gallons per minute. An aquifer test and a digital ground-water flow model were used to estimate aquifer and confining-layer hydraulic characteristics. Using these methods, the transmissivity of the aquifer was estimated to be within a range of 400 to 700 square feet per day. The leakance of the confining layer was determined to be within a range from 0 to 0.13 per day, with a best estimate value in a range from 4.3 x 10-8 to 7.7 x 10-8 per day. Analyses of water samples collected as part of this study and of water-quality data from earlier work indicate that a large areal change in major-ion chemistry occurs in ground water in the Roubidoux aquifer in northeastern Oklahoma. The ground water in the easternmost part of the study unit has relatively small dissolved-solids concentrations (less than 200 milligrams per liter) with calcium, magnesium, and bicarbonate as the major ions. Ground water in the westernmost part of the study unit has relatively large dissolved-solids concentrations (greater than 800 milligrams per liter) with sodium and chloride as the major ions. A transition zone of intermediate sodium, chloride, and dissolved-solids concentrations exists between the easternmost and westernmost parts of the study unit. Three water-quality problems are apparent in the Roubidoux aquifer in northeast Oklahoma: (1

  7. What function tells about structure in heterogeneous aquifers

    NASA Astrophysics Data System (ADS)

    Lischeid, Gunnar; Steidl, Jörg; Merz, Christoph; Dannowski, Ralf

    2016-04-01

    transformation of the input signal, that is, the temporal structure of the seepage flux in the vadose zone. In the uppermost unconfined aquifer the degree of that transformation linearly increased with the thickness of the overlying vadose zone, whereas there was no clear relationship for wells screened in the underlying confined aquifer. Scores of that principal component could even be used to assess the thickness of the vadose zone in the respective recharge area for the confined aquifer. Secondly, longitudinal discharge measurements of the catchment's main stream during baseflow conditions were used to identify gaining or loosing reaches, giving indirect evidence for major aquifer and aquitard layers. Thirdly, water level data from about 1100 small lakes as well as from the streams derived from a high-resolution airborne laser scan survey were used for setting up a map of groundwater head of the uppermost aquifer. Comparison with groundwater head data from deeper wells revealed substantial deviations in certain parts of the catchment, confirming the existence of a separate deeper aquifer. Last but not least, additional evidence was provided by groundwater quality data. Findings from the different approaches were merged. This resulted in a consistent conceptual model which will be tested in next step by a distributed hydrological model.

  8. SIMULATION OF SURFACTANT-ENHANCED AQUIFER REMEDIATION

    EPA Science Inventory

    Surfactant-enhanced aquifer remediation (SEAR) is currently under active investigation as one of the most promising alternatives to conventional pump-and-treat remediation for aquifers contaminated by dense nonaqueous phase organic liquids. An existing three-dimensional finite-di...

  9. Evaluation of health risks for contaminated aquifers.

    PubMed Central

    Piver, W T; Jacobs, T L; Medina, M A

    1997-01-01

    This review focuses on progress in the development of transport models for heterogeneous contaminated aquifers, the use of predicted contaminant concentrations in groundwater for risk assessment for heterogeneous human populations, and the evaluation of aquifer remediation technologies. Major limitations and areas for continuing research for all methods presented in this review are identified. Images Figure 2. PMID:9114282

  10. The Sparta Aquifer: A Sustainable Water Resource?

    USGS Publications Warehouse

    McKee, Paul W.; Hays, Phillip D.

    2002-01-01

    Introduction The Sparta aquifer is an aquifer of regional importance within the Mississippi embayment aquifer system. It consists of varying amounts of unconsolidated sand, inter-stratified with silt and clay lenses within the Sparta Sand of the Claiborne Group. It extends from south Texas, north into Louisiana, Arkansas, and Tennessee, and eastward into Mississippi and Alabama (fig. 1). On both the west and east sides of the Mississippi embayment, the Sparta aquifer is exposed at the surface (outcrops) and is locally unconfined; it becomes confined as it dips toward the axis of the embayment, (generally corresponding with the Mississippi River) and southward toward the Gulf of Mexico where it is deeply buried in the subsurface (Hosman, 1968). Generalized ground-water flow in the Sparta aquifer is from the outcrop areas to the axis (center) of the embayment (fig. 2). In Arkansas, the Sparta aquifer outcrops parallel to the Fall Line at the western extreme of the Mississippi embayment (the Fall Line is a line dividing the mountainous highlands of Arkansas from the lowland area); and the formation dips from its outcrop area to the southeast. The Sparta aquifer supplies water for municipalities, industries such as paper production, and to a lesser degree, irrigation of agricultural crops (fig. 3). This report highlights hydrologic conditions of the aquifer in Arkansas County as an example of how water use is affecting water levels.

  11. Induced infiltration in aquifers with ambient flow

    NASA Astrophysics Data System (ADS)

    Wilson, John L.

    1993-10-01

    Well water quality depends on the relative amounts of water drawn from the pumped aquifer and nearby surface water bodies, such as streams, lakes, and wetlands. Although a surface water body may normally gain water from the aquifer, pumping can reverse gradients, causing it to lose water near the well. Surface water then enters the well by induced infiltration. Two-dimensional vertically integrated models of induced infiltration are developed for various combinations of aquifer geometry and sources of recharge. The models, which have applications in wellhead protection, aquifer pollution characterization, and aquifer remediation, are presented graphically. They show that the propensity for and rate of induced infiltration are enhanced by higher pumping rates, proximity of the well to the stream, and the presence of nearby barrier boundaries. The propensity and rate are reduced by the presence of other surface water bodies. Ambient groundwater discharge rate to the surface water body also plays a role, but not its source, whether it is from local vertical recharge, lateral inflow, or both. The results are also largely indifferent to whether the aquifer transmissivity is assumed to be a constant, or a function of water table elevation. Finally, if the well is close enough to the surface water body, say, less than 5% of the aquifer width, then the aquifer acts as if it were semi-infinite.

  12. Evaluation of health risks for contaminated aquifers.

    PubMed

    Piver, W T; Jacobs, T L; Medina, M A

    1997-02-01

    This review focuses on progress in the development of transport models for heterogeneous contaminated aquifers, the use of predicted contaminant concentrations in groundwater for risk assessment for heterogeneous human populations, and the evaluation of aquifer remediation technologies. Major limitations and areas for continuing research for all methods presented in this review are identified.

  13. Decoding the Structure of Hard Rock Aquifers in Peninsula India Using Participatory Groundwater Mapping

    NASA Astrophysics Data System (ADS)

    Srinivasan, V.

    2015-12-01

    Groundwater depletion is a major problem in the Arkavathy Basin in South India. It is also the probable cause of declining flows in the Arkavathy River. However, investigating groundwater and developing sustainable management strategies is extremely challenging in a data-scarce environment where there is very little historical data; often the data are missing, flawed or biased. Almost nothing is known about the structure of fracture aquifers, which makes modeling groundwater flows impossible. No aquifer maps are available from government agencies and a review of the available literature and discussions with experts suggests several contradicting views on the structure of fracture aquifers. Using data from over a hundred borewell camera scans in a milli-watershed covering 6 sq km, we tested multiple hypothesis on possible structures. We are able to recreate the 3-D structure of fracture aquifers. Using data from a participatory groundwater monitoring program we are also able to interpret seasonal changes in water levels and possible recharge pathways.

  14. Pilot study of in-situ thermal treatment for the remediation of pentachlorophenol-contaminated aquifers.

    PubMed

    Tse, K K; Lo, S L; Wang, J W

    2001-12-15

    A field pilot study of a steam injection method for the treatment of pentachlorophenol (PCP)-contaminated soil and groundwater has shown potential advantages over the traditional pump-and-treatment method. Low-pressure steam was injected 10 m below the ground surface. The ground water temperature was raised to 118 degrees C over a period of 3 months. Five soil and groundwater sampling events were performed during the pilot test. Results of sample analysis showed that the PCP concentrations in deep aquifer soil decreased dramatically whereas those in shallow aquifer soil increased. It was concluded that raising the groundwater temperature caused PCP in deep aquifer soil to be desorbed, and as the hot, deep groundwater circulated upward, it brought the desorbed PCP to the shallow aquifer. By using steam injection, PCP can be desorbed from soil and moved upward to the ground surface so that it can be removed more easily through pump-and-treatment.

  15. Recharge rates and aquifer hydraulic characteristics for selected drainage basins in middle and east Tennessee

    USGS Publications Warehouse

    Hoos, A.B.

    1990-01-01

    diffusivity are derived from estimates of the streamflow recession index and drainage density for 75 drainage basins; values range from 3,300 to 130,000 ft^2/d (feet squared per day). Basin-specific and site-specific estimates of transmissivity are computed from estimates of hydraulic diffusivity and specific-capacity test data, respectively. Basin-specific, or areal, estimates of transmissivity range from 22 to 1,300 ft^2/d, with a mean of 240 ft^2/d In general, areal transmissivity is highest for basins underlain by the Cumberland Plateau aquifer (mean value 480 ft^2/d) and lowest for basins underlain by the Central Basin aquifer (mean value 79 ft^2/d). Mean transmissivity values for the Highland Rim, Valley and Ridge, and Blue Ridge aquifer are 320,140, and 120 ft^2/d respectively. Site-specific estimates of transmissivity, computed from specific-capacity data from 118 test wells in Middle and East Tennessee range from 2 to 93,000 ft^2/d with a mean of 2,600 ft^2/d Mean transmissivity values for the Cumberland Plateau, Highland Rim, Central Basin, Valley and Ridge, and Blue Ridge aquifers are 2,800,1,200, 7,800, 390, and 65Oft Id, respectively.

  16. Concentration history during pumping from a leaky aquifer with stratified initial concentration

    USGS Publications Warehouse

    Goode, Daniel J.; Hsieh, Paul A.; Shapiro, Allen M.; Wood, Warren W.; Kraemer, Thomas F.

    1993-01-01

    Analytical and numerical solutions are employed to examine the concentration history of a dissolved substance in water pumped from a leaky aquifer. Many aquifer systems are characterized by stratification, for example, a sandy layer overlain by a clay layer. To obtain information about separate hydrogeologic units, aquifer pumping tests are often conducted with a well penetrating only one of the layers. When the initial concentration distribution is also stratified (the concentration varies with elevation only), the concentration breakthrough in the pumped well may be interpreted to provide information on aquifer hydraulic and transport properties. To facilitate this interpretation, we present some simple analytical and numerical solutions for limiting cases and illustrate their application to a fractured bedrock/glacial drift aquifer system where the solute of interest is dissolved radon gas. In addition to qualitative information on water source, this method may yield estimates of effective porosity and saturated thickness (or fracture transport aperture) from a single-hole test. Little information about dispersivity is obtained because the measured concentration is not significantly affected by dispersion in the aquifer.

  17. Geochemistry of the Arbuckle-Simpson Aquifer

    USGS Publications Warehouse

    Christenson, Scott; Hunt, Andrew G.; Parkhurst, David L.; Osborn, Noel I.

    2009-01-01

    The Arbuckle-Simpson aquifer in south-central Oklahoma provides water for public supply, farms, mining, wildlife conservation, recreation, and the scenic beauty of springs, streams, and waterfalls. A new understanding of the aquifer flow system was developed as part of the Arbuckle-Simpson Hydrology Study, done in 2003 through 2008 as a collaborative research project between the State of Oklahoma and the Federal government. The U.S. Geological Survey collected 36 water samples from 32 wells and springs in the Arbuckle-Simpson aquifer in 2004 through 2006 for geochemical analyses of major ions, trace elements, isotopes of oxygen and hydrogen, dissolved gases, and dating tracers. The geochemical analyses were used to characterize the water quality in the aquifer, to describe the origin and movement of ground water from recharge areas to discharge at wells and springs, and to determine the age of water in the aquifer.

  18. Cyclic injection, storage, and withdrawal of heated water in a sandstone aquifer at St. Paul, Minnesota: Field observations, preliminary model analysis, and aquifer thermal efficiency

    USGS Publications Warehouse

    Miller, Robert T.

    1989-01-01

    The Franconia-Ironton-Galesville aquifer is a consolidated sandstone, approximately 60 m thick, the top of which is approximately 180 m below the land surface. It is confined above by the St. Lawrence Formation--a dolomitic sandstone 8-m thick--and below by the Eau Claire Formation--a shale 30-m thick. Initial hydraulic testing with inflatable packers indicated that the aquifer has four hydraulic zones with distinctly different values of relative horizontal hydraulic conductivity. The thickness of each zone was determined by correlating data from geophysical logs, core samples, and the inflatablepacker tests.

  19. Transport Behavior of Groundwater Protozoa and Protozoan-Sized Microspheres in Sandy Aquifer Sediments

    PubMed Central

    Harvey, R. W.; Kinner, N. E.; Bunn, A.; MacDonald, D.; Metge, D.

    1995-01-01

    Transport behaviors of unidentified flagellated protozoa (flagellates) and flagellate-sized carboxylated microspheres in sandy, organically contaminated aquifer sediments were investigated in a small-scale (1 to 4-m travel distance) natural-gradient tracer test on Cape Cod and in flow-through columns packed with sieved (0.5-to 1.0-mm grain size) aquifer sediments. The minute (average in situ cell size, 2 to 3 (mu)m) flagellates, which are relatively abundant in the Cape Cod aquifer, were isolated from core samples, grown in a grass extract medium, labeled with hydroethidine (a vital eukaryotic stain), and coinjected into aquifer sediments along with bromide, a conservative tracer. The 2-(mu)m flagellates appeared to be near the optimal size for transport, judging from flowthrough column experiments involving a polydispersed (0.7 to 6.2 (mu)m in diameter) suspension of carboxylated microspheres. However, immobilization within the aquifer sediments accounted for a log unit reduction over the first meter of travel compared with a log unit reduction over the first 10 m of travel for indigenous, free-living groundwater bacteria in earlier tests. High rates of flagellate immobilization in the presence of aquifer sediments also was observed in the laboratory. However, immobilization rates for the laboratory-grown flagellates (initially 4 to 5 (mu)m) injected into the aquifer were not constant and decreased noticeably with increasing time and distance of travel. The decrease in propensity for grain surfaces was accompanied by a decrease in cell size, as the flagellates presumably readapted to aquifer conditions. Retardation and apparent dispersion were generally at least twofold greater than those observed earlier for indigenous groundwater bacteria but were much closer to those observed for highly surface active carboxylated latex microspheres. Field and laboratory results suggest that 2-(mu)m carboxylated microspheres may be useful as analogs in investigating several

  20. Transport behavior of groundwater protozoa and protozoan-sized microspheres in sandy aquifer sediments

    USGS Publications Warehouse

    Harvey, R.W.; Kinner, N.E.; Bunn, A.; MacDonald, D.; Metge, D.

    1995-01-01

    Transport behaviors of unidentified flagellated protozoa (flagellates) and flagellate-sized carboxylated microspheres in sandy, organically contaminated aquifer sediments were investigated in a small-scale (1 to 4-m travel distance) natural-gradient tracer test on Cape Cod and in flow-through columns packed with sieved (0.5-to 1.0-mm grain size) aquifer sediments. The minute (average in situ cell size, 2 to 3 ??m) flagellates, which are relatively abundant in the Cape Cod aquifer, were isolated from core samples, grown in a grass extract medium, labeled with hydroethidine (a vital eukaryotic stain), and coinjected into aquifer sediments along with bromide, a conservative tracer. The 2-??m flagellates appeared to be near the optimal size for transport, judging from flowthrough column experiments involving a polydispersed (0.7 to 6.2 ??m in diameter) suspension of carboxylated microspheres. However, immobilization within the aquifer sediments accounted for a log unit reduction over the first meter of travel compared with a log unit reduction over the first 10 m of travel for indigenous, free-living groundwater bacteria in earlier tests. High rates of flagellate immobilization in the presence of aquifer sediments also was observed in the laboratory. However, immobilization rates for the laboratory-grown flagellates (initially 4 to 5 ??m) injected into the aquifer were not constant and decreased noticeably with increasing time and distance of travel. The decrease in propensity for grain surfaces was accompanied by a decrease in cell size, as the flagellates presumably readapted to aquifer conditions. Retardation and apparent dispersion were generally at least twofold greater than those observed earlier for indigenous groundwater bacteria but were much closer to those observed for highly surface active carboxylated latex microspheres. Field and laboratory results suggest that 2- ??m carboxylated microspheres may be useful as analogs in investigating several abiotic

  1. Using existing data to estimate aquifer properties, Great Lakes Region, USA

    USGS Publications Warehouse

    Darner, Robert A.; Sheets, Rodney A.

    2012-01-01

    To determine specific storage and porosity, areally limited and time-consuming aquifer tests are frequently done. Hydrogeologic studies often do not have the resources to collect such data and rely on existing data sources for aquifer properties. An alternative tool for determining these aquifer properties is the analysis of earth tides. The objective of this study was to determine whether existing water-level and barometric-pressure data could be used to determine aquifer properties, such as porosity and specific storage, on a regional scale. In this study, national databases from the Great Lakes Region were queried for continuous records of groundwater-level and barometric-pressure data. Records from 37 selected wells were then analyzed for barometric efficiency and earth-tide responses. Specific-storage (Ss) and porosity values were determined, and the quality of the results were assessed with a measure of the "goodness of fit" (percent variance) of reconstruction of the response. Records from wells completed in several aquifer systems were analyzed with varying degrees of success. Aquifer Ss values ranging from 5.9 x 10-8 to 3.8 x 10-6/m were derived, with percent variance of reconstruction ranging from 1% to 78%. Comparisons with aquifer and laboratory testing of Ss and porosity are favorable if the percent variance of reconstruction is above about 30%. Although the earth-tide-analysis method is not suitable for every situation, the Ss and porosity of aquifers can, in many places, be estimated with existing water-level and barometric-pressure data or with data that are relatively inexpensive to collect.

  2. Fecal Fat: The Test

    MedlinePlus

    ... limited. Home Visit Global Sites Search Help? Fecal Fat Share this page: Was this page helpful? Also known as: Qualitative or Quantitative Stool Fat; Stool Lipids; 72 Hour Fecal Fat; Fat Stain ...

  3. Evaluation of field methods for vertical high resolution aquifer characterization

    NASA Astrophysics Data System (ADS)

    Vienken, T.; Tinter, M.; Rogiers, B.; Leven, C.; Dietrich, P.

    2012-12-01

    The delineation and characterization of subsurface (hydro)-stratigraphic structures is one of the challenging tasks of hydrogeological site investigations. The knowledge about the spatial distribution of soil specific properties and hydraulic conductivity (K) is the prerequisite for understanding flow and fluid transport processes. This is especially true for heterogeneous unconsolidated sedimentary deposits with a complex sedimentary architecture. One commonly used approach to investigate and characterize sediment heterogeneity is soil sampling and lab analyses, e.g. grain size distribution. Tests conducted on 108 samples show that calculation of K based on grain size distribution is not suitable for high resolution aquifer characterization of highly heterogeneous sediments due to sampling effects and large differences of calculated K values between applied formulas (Vienken & Dietrich 2011). Therefore, extensive tests were conducted at two test sites under different geological conditions to evaluate the performance of innovative Direct Push (DP) based approaches for the vertical high resolution determination of K. Different DP based sensor probes for the in-situ subsurface characterization based on electrical, hydraulic, and textural soil properties were used to obtain high resolution vertical profiles. The applied DP based tools proved to be a suitable and efficient alternative to traditional approaches. Despite resolution differences, all of the applied methods captured the main aquifer structure. Correlation of the DP based K estimates and proxies with DP based slug tests show that it is possible to describe the aquifer hydraulic structure on less than a meter scale by combining DP slug test data and continuous DP measurements. Even though correlations are site specific and appropriate DP tools must be chosen, DP is reliable and efficient alternative for characterizing even strongly heterogeneous sites with complex structured sedimentary aquifers (Vienken et

  4. Aquifers productivity in the Pan-African context

    NASA Astrop