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Sample records for 72-hour aquifer test

  1. [Hypoglycemia in nondiabetic patients: When is the 72-hour-fast test required and how can it be interpreted?].

    PubMed

    Vezzosi, Delphine; Bennet, Antoine; Grunenwald, Solange; Caron, Philippe

    2016-06-01

    Whereas hypoglycaemia is uncommon in nondiabetic patients, it is a frequent reason for consultation. Hypoglycaemia is confirmed when criteria of Whipple's triad are fulfilled. If a venous sample cannot be collected when hypoglycemia occurs spontaneously, a 72-hour-fast test should be performed firstly to affirm the reality of hypoglycaemia and secondly to make the etiological diagnosis. Before carrying out this long and expensive test, the obvious causes of hypoglycaemia must be ruled out: iatrogenic, severe prolonged undernutrition, liver or renal deficiency, adrenal insufficiency, IGFII or pro-IGFII secreting tumours…At the time of hypoglycemia, plasma insulin≥3mUI/L, C-peptide≥0.6ng/mL, proinsulin≥5pmol/L associated with plasma beta-hydroxybutyrate≤2700μmol/L provide evidence for inappropriate insulin secretion. The lack of hypoglycaemia after a 72-hour-fast test rules out, in the majority of cases, organic hypoglycaemia. PMID:27208915

  2. 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., Jr.; 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)

  3. 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).

  4. 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

  5. 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)

  6. Multidepth pumping tests in deep aquifers.

    PubMed

    Alam, N; Olsthoorn, T N

    2014-09-01

    Multidepth pumping tests (MDPTs), in which different sections of a screen are pumped in sequence, are not being used by hydrogeologists, despite the capability of such tests to resolve uncertainties in the estimation of aquifer characteristics. MDPTs can be used to discern the effects of partial penetration and vertical anisotropy. This article demonstrates the use of MDPTs for a deep and vertically anisotropic aquifer, based on a real and unique series of pumping tests conducted in the Indus Basin. Traditional single-layer methods, which incorporate partial penetration and vertical scaling, were employed to evaluate these tests. However, the drawdowns of the 19 piezometers at different depths for which times series data were available could not be matched, presumably because of the layered structure of the aquifer. Numerical (MODFLOW) and multilayer analytical (Hemker and Maas 1987; Hemker 1999) approaches were used to assess the benefits of using MDPTs in the analysis of deep layered and anisotropic aquifers. The multilayer analytical solution results are consistent with the measured and numerically computed drawdowns. The original step-drawdown data were used to verify the model independently. The results of statistical analyses indicate that the parameters for a three-layer system are uniquely estimated. A sensitivity analysis showed that aquifer depths greater than 900 m do not affect the drawdown. The multilayer analytical solution was implemented in MATLAB and can be found in the online version of this article. This multilayer analytical approach was implemented in MLU by Hemker and Randall (2013) for up to 40 layers. The results of this study will be useful in groundwater management, exploration, and optimal well depth estimation for the Indus Basin aquifer and other vertically heterogeneous aquifers. PMID:24428328

  7. Repeated cycles with 72-hour continuous infusion interleukin-2 in kidney cancer and melanoma.

    PubMed

    Quan, Walter; Brick, Wendy; Vinogradov, Mikhail; Taylor, W Chris; Khan, Nawazish; Burgess, Russell

    2004-06-01

    While high-dose bolus inpatient interleukin-2 is generally given on 8-week cycles, continuous infusion interleukin-2 could potentially allow for more rapidly repeated cycles. Fourteen (14) patients with an Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 0 or 1, having either kidney cancer (6) or melanoma (8), have been treated with continuous infusion (CIV) interleukin-2 (IL-2) 18 MIU/m(2)/24 hours for 72 hours. Cycles were repeated every 3 weeks up to 4 cycles, then every 3-4 weeks for 2 cycles, then every 6-8 weeks, until progression or intolerable toxicity. All patients received famotidine 20 mg intravenously (i.v.) twice per day during the 72-hour infusions. Patient characteristics included a median ECOG performance status of 1; median age = 63 (range: 25-79); most common metastatic sites: lung (9), bone (5), lymph nodes (5), and the liver (3). No patients with metastatic kidney cancer underwent a nephrectomy prior to interleukin-2. Median number of cycles received = 5 (1-9). No patients required Intensive Care Unit (ICU) admission. There have been no treatment-related deaths. Most common toxicities have been rigors, fever, nausea/emesis, and the reversible elevation of creatinine. One complete response and three partial responses (67% response rate; 95% confidence interval: 30%-90%) have been seen in kidney cancer, and two partial responses (25% response rate; 95% confidence interval: 7%-60%) have occurred in melanoma. Median survival has not been reached at >9+ months. Responding sites include the liver, bone, lung, lymph node and subcutaneous sites. Inpatient 72-hour continuous infusion interleukin-2 at this dose and schedule is well tolerated by patients with an ECOG performance status of 0 or 1 and has activity in kidney cancer and melanoma. PMID:15285881

  8. 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. PMID:27441405

  9. 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

  10. 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

  11. 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.

  12. 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

  13. Phase I and pharmacologic study of 72-hour infused 5-fluorouracil and hyperfractionated cyclical radiation

    SciTech Connect

    Byfield, J.E.; Frankel, S.S.; Sharp, T.R.; Hornbeck, C.L.; Callipari, F.B.

    1985-04-01

    The authors have studied 21 patients infused for 72 hours with 5- Fluorouracil (5-FU) at progressive doses combined with hyperfractionated radiation. The schedule was chosen as being one capable of inducing 5-FU radiosensitization (RS). All patients were started at a daily 5-FU dose of 40 mg/kg/24 hours; doses were then escalated with each subsequent treatment cycle to limiting toxicity or until taken off study. Patients received between one and six infusion cycles. Every treatment cycle included coincident hyperfractionated radiation to various body areas including the abdomen, chest, and head and neck region. Radiation fractionation was invariant; 1,000 rad were delivered in four equal fractions. Two fractions of 250 rad each were given on days 1 and 2 of each three day 5-FU cycle, i.e. at approximately 0, 8, 24, and 32 hours into the drug infusion. Patients were followed for toxicity; serum 5-FU concentrations were determined using a high pressure liquid chromatographic assay. 5-FU clearances were calculated from the mean serum drug levels and the infused drug dose. The toxicity spectrum was not found to be significantly different from infused drug alone in this dose range except when the head and neck region received coincident irradiation. In that region the two anticipated toxicities combined in what appears to be a synergistic fashion to enhance mucositis. Most toxicities including gastrointestinal and bone marrow appeared dependent on the mean serum 5-FU level as did mucositis itself. 5-FU clearance was found to be non-linear in this dose region but did not appear influenced by radiation to any part of the body.

  14. 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

  15. 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.

    2016-01-01

    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

  16. 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

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

    DOE PAGESBeta

    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.

  18. Hypoglycemia Secondary to Sulfonylurea Ingestion in a Patient with End Stage Renal Disease: Results from a 72-Hour Fast.

    PubMed

    Abraham, Alice; Rubin, Mishaela; Accili, Domenico; Bilezikian, John P; Pajvani, Utpal B

    2015-01-01

    Insulin, proinsulin, and C-peptide levels increase with sulfonylurea exposure but the acuity of increase has not been described in dialysis patients. We present a case of a dialysis patient who presented with hypoglycemia and was found to have accidental sulfonylurea ingestion. This is a 73-year-old man with ESRD on peritoneal dialysis, without history of diabetes, who presented with hypoglycemia. Past medical history includes multiple myeloma, congestive heart failure, and hypertension. At initial presentation, his blood glucose was 47 mg/dL, with concomitant elevations in the following: C-peptide 30.5 (nl: 0.8-3.5 ng/mL), insulin 76 (nl: 3-19 μIU/mL), and proinsulin 83.3 (nl: ≤8.0 pmol/L). During the 72-hour fast, which he completed without hypoglycemia, insulin declined to be within normal limits (to 12 μIU/mL); proinsulin (to 12.1 pmol/L) and C-peptide (to 7.2 ng/mL) levels decreased but remained elevated. The sulfonylurea screen ultimately returned positive for glipizide, clinching the diagnosis. This is the first reported case which characterizes the chronic elevation of proinsulin in a patient with ESRD, as well as its dramatic increase after a presumed solitary exposure to sulfonylurea. The 72-hour fast conducted gives insight into the clearance of insulin, proinsulin, and C-peptide after sulfonylurea ingestion in ESRD. PMID:26664768

  19. Optimized system to improve pumping rate stability during aquifer tests.

    PubMed

    Young, Michael H; Rasmussen, Todd C; Lyons, F Comer; Pennell, Kurt D

    2002-01-01

    Aquifer hydraulic properties are commonly estimated using aquifer tests, which are based on an assumption of a uniform and constant pumping rate. Substantial uncertainties in the flow rate across the borehole-formation interface can be induced by dynamic head losses, caused by rapid changes in borehole water levels early in an aquifer test. A system is presented that substantially reduces these sources of uncertainty by explicitly accounting for dynamic head losses. The system which employs commonly available components (including a datalogger, pressure transducers, a variable-speed pump motor, a flow controller, and flowmeters), is inexpensive, highly mobile, and easily set up. It optimizes the flow rate at the borehole-formation interface, making it suitable for any type of aquifer test, including constant, step, or ramped withdrawal and injection, as well as sinusoidal. The system was demonstrated for both withdrawal and injection tests in three aquifers at the Savannah River Site. No modifications to the control system were required, although a small number of characteristics of the pumping and monitoring system were added to the operating program. The pumping system provided a statistically significant, constant flow rate with time. The range in pumping variability (95% confidence interval) was from +/- 2.58 x 10(-4) L/sec to +/- 9.07 x 10(-4) L/sec, across a wide range in field and aquifer conditions. PMID:12425350

  20. Traditional analysis of aquifer tests: Comparing apples to oranges?

    NASA Astrophysics Data System (ADS)

    Wu, Cheng-Mau; Yeh, Tian-Chyi J.; Zhu, Junfeng; Lee, Tim Hau; Hsu, Nien-Sheng; Chen, Chu-Hui; Sancho, Albert Folch

    2005-09-01

    Traditional analysis of aquifer tests uses the observed drawdown at one well, induced by pumping at another well, for estimating the transmissivity (T) and storage coefficient (S) of an aquifer. The analysis relies on Theis' solution or Jacob's approximate solution, which assumes aquifer homogeneity. Aquifers are inherently heterogeneous at different scales. If the observation well is screened in a low-permeability zone while the pumping well is located in a high-permeability zone, the resulting situation contradicts the homogeneity assumption in the traditional analysis. As a result, what does the traditional interpretation of the aquifer test tell us? Using numerical experiments and a first-order correlation analysis, we investigate this question. Results of the investigation suggest that the effective T and S for an equivalent homogeneous aquifer of Gaussian random T and S fields vary with time as well as the principal directions of the effective T. The effective T and S converge to the geometric and arithmetic means, respectively, at large times. Analysis of the estimated T and S, using drawdown from a single observation well, shows that at early time both estimates vary with time. The estimated S stabilizes rapidly to the value dominated by the storage coefficient heterogeneity in between the pumping and the observation wells. At late time the estimated T approaches but does not equal the effective T. It represents an average value over the cone of depression but influenced by the location, size, and degree of heterogeneity as the cone of depression evolves.

  1. Comparison of Cerebral Oximeter and Pulse Oximeter Values in the First 72 Hours in Premature, Asphyctic and Healthy Newborns

    PubMed Central

    Kaya, A; Okur, M; Sal, E; Peker, E; Köstü, M; Tuncer, O; Kirimi, E

    2014-01-01

    ABSTRACT Aim: The monitoring of oxygenation is essential for providing patient safety and optimal results. We aimed to determine brain oxygen saturation values in healthy, asphyctic and premature newborns and to compare cerebral oximeter and pulse oximeter values in the first 72 hours of life in neonatal intensive care units. Methods: This study was conducted at the neonatal intensive care unit (NICU) of Van Yüzüncü Yil University Research and Administration Hospital. Seventy-five neonatal infants were included in the study (28 asphyxia, 24 premature and 23 mature healthy infants for control group). All infants were studied within the first 72 hours of life. We used a Somanetics 5100C cerebral oximeter (INVOS cerebral/somatic oximeter, Troy, MI, USA). The oxygen saturation information was collected by a Nellcor N-560 pulse oximeter (Nellcor-Puriton Bennet Inc, Pleasanton, CA, USA). Results: In the asphyxia group, the cerebral oximeter average was 76.85 ± 14.1, the pulse oximeter average was 91.86 ± 5.9 and the heart rate average was 139.91 ± 22.3. Among the premature group, the cerebral oximeter average was 79.08 ± 9.04, the pulse oximeter average was 92.01 ± 5.3 and the heart rate average was 135.35 ± 17.03. In the control group, the cerebral oximeter average was 77.56 ± 7.6, the pulse oximeter average was 92.82 ± 3.8 and the heart rate average was 127.04 ± 19.7. Conclusion: Cerebral oximeter is a promising modality in bedside monitoring in neonatal intensive care units. It is complementary to pulse oximeter. It may be used routinely in neonatal intensive care units. PMID:25867556

  2. Hypoglycemia Secondary to Sulfonylurea Ingestion in a Patient with End Stage Renal Disease: Results from a 72-Hour Fast

    PubMed Central

    Abraham, Alice; Rubin, Mishaela; Accili, Domenico; Pajvani, Utpal B.

    2015-01-01

    Insulin, proinsulin, and C-peptide levels increase with sulfonylurea exposure but the acuity of increase has not been described in dialysis patients. We present a case of a dialysis patient who presented with hypoglycemia and was found to have accidental sulfonylurea ingestion. This is a 73-year-old man with ESRD on peritoneal dialysis, without history of diabetes, who presented with hypoglycemia. Past medical history includes multiple myeloma, congestive heart failure, and hypertension. At initial presentation, his blood glucose was 47 mg/dL, with concomitant elevations in the following: C-peptide 30.5 (nl: 0.8–3.5 ng/mL), insulin 76 (nl: 3–19 μIU/mL), and proinsulin 83.3 (nl: ≤8.0 pmol/L). During the 72-hour fast, which he completed without hypoglycemia, insulin declined to be within normal limits (to 12 μIU/mL); proinsulin (to 12.1 pmol/L) and C-peptide (to 7.2 ng/mL) levels decreased but remained elevated. The sulfonylurea screen ultimately returned positive for glipizide, clinching the diagnosis. This is the first reported case which characterizes the chronic elevation of proinsulin in a patient with ESRD, as well as its dramatic increase after a presumed solitary exposure to sulfonylurea. The 72-hour fast conducted gives insight into the clearance of insulin, proinsulin, and C-peptide after sulfonylurea ingestion in ESRD. PMID:26664768

  3. 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.

  4. Diagnostic tests for conceptualizing transport in bedrock aquifers

    NASA Astrophysics Data System (ADS)

    Worthington, Stephen R. H.

    2015-10-01

    Transport in bedrock aquifers is complex because there is often substantial flow through fractures, and the apertures and interconnectivity of these fractures are usually uncertain. Single-porosity numerical models often give satisfactory results for simulating flow. However, simulating transport is more challenging and results based on single-porosity assumptions can yield inaccurate results. Seven cases are reviewed where travel times were found to be unexpectedly short. Results show that dual-porosity flow is common, with advective flow through fracture networks and immobile storage in the matrix. However, in some cases a dual- or multiple-permeability (or porosity) approach provides better simulations of aquifer behavior. Fracture porosity of bedrock aquifers is usually <1%, resulting in rapid groundwater velocities in many aquifers. Overestimation of the effective porosity is the most common reason for the overestimation of travel times. Residence times of artificial tracers in bedrock aquifers are typically two to three orders of magnitude less than residence times of environmental tracers because the latter are retarded by matrix diffusion. Fourteen diagnostic tests for determining the appropriate conceptual model for bedrock aquifers are described.

  5. Absolute hydraulic conductivity estimates from aquifer pumping and tracer tests in a stratified aquifer

    SciTech Connect

    Thorbjarnarson, K.W.; Huntley, D.; McCarty, J.J.

    1998-01-01

    Independent estimates of absolute hydraulic conductivity were obtained by a standard aquifer pumping test and a forced-gradient tracer test in a highly heterogeneous aquifer. An aquifer hydraulic test was conducted to evaluate the average hydraulic conductivity (K), and to establish steady-state flow for the tracer test. An average K of 48 m/day was interpreted from the draw-down data in a fully screened well. Type-curve matching and simulation with MODFLOW of the hydraulic response in partially screened wells indicates K of 10 to 15 m/day for the upper section and 71 to 73 m/day for the deeper section. Iodide and fluorescent dye tracers were injected at low rates in wells located approximately 8 m upgradient of the production well. Tracer breakthrough was monitored in the production well and at ten depth intervals within the fully screened monitoring well. Interpretation of tracer response in the production well reveals tracer transport is limited to a 3.9 m thick section of the 20 m thick aquifer, with a hydraulic conductivity of 248 m/day. However, the depth distribution of these permeable strata cannot be determined from the production well tracer response. When sampled at 1.5 m depth intervals in the monitoring well, breakthrough was observed in only three intervals along the entire 18.2 m screened well. K estimates from tracer travel time within discrete high-permeability strata range from 31 to 317 m/day. Inclusion of permeameter K estimates for the lower permeability aquifer sands result in a range in relative K of 0.01 to 1.0. This field site has the highest absolute K estimate for a discrete stratum and the widest range in relative hydraulic conductivity among research field sites with K estimates for discrete strata. Within such a highly stratified aquifer, the use of an average K from an aquifer pumping test to predict solute transport results in great underestimation of transport distances for a given time period.

  6. 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.

  7. 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.

  8. 18 CFR 806.12 - Constant-rate aquifer testing.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... groundwater availability analysis to determine the availability of water during a 1-in-10-year recurrence... 18 Conservation of Power and Water Resources 2 2013-04-01 2012-04-01 true Constant-rate aquifer testing. 806.12 Section 806.12 Conservation of Power and Water Resources SUSQUEHANNA RIVER...

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

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... groundwater availability analysis to determine the availability of water during a 1-in-10-year recurrence... 18 Conservation of Power and Water Resources 2 2012-04-01 2012-04-01 false Constant-rate aquifer testing. 806.12 Section 806.12 Conservation of Power and Water Resources SUSQUEHANNA RIVER...

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

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... groundwater availability analysis to determine the availability of water during a 1-in-10-year recurrence... 18 Conservation of Power and Water Resources 2 2010-04-01 2010-04-01 false Constant-rate aquifer testing. 806.12 Section 806.12 Conservation of Power and Water Resources SUSQUEHANNA RIVER...

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

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... groundwater availability analysis to determine the availability of water during a 1-in-10-year recurrence... 18 Conservation of Power and Water Resources 2 2014-04-01 2014-04-01 false Constant-rate aquifer testing. 806.12 Section 806.12 Conservation of Power and Water Resources SUSQUEHANNA RIVER...

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

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... groundwater availability analysis to determine the availability of water during a 1-in-10-year recurrence... 18 Conservation of Power and Water Resources 2 2011-04-01 2011-04-01 false Constant-rate aquifer testing. 806.12 Section 806.12 Conservation of Power and Water Resources SUSQUEHANNA RIVER...

  13. Compilation and analyses of aquifer performance tests in eastern Kansas

    USGS Publications Warehouse

    Reed, T.B.; Burnett, R.D.

    1985-01-01

    Selected aquifer-test data from 36 counties in eastern Kansas were collected from numerous sources and publications in order to produce a documented compilation of aquifer tests in one report. Data were obtained chiefly from private consulting firms and from government agencies. Hydraulic properties determined included transmissivity, storage coefficient (where observation well was available), and in some cases hydraulic properties of a confining layer. The aquifers tested comprised three main types of rocks--consolidated rock deposits, glacial deposits, and alluvial deposits that include the ' Equus beds, ' an extensive alluvial deposit in south-central Kansas. The Theis recovery equation and the Cooper-Jacob modified nonequilibrium equation were the two principal solution methods used. Other methods used included the Theis nonequilibrium equation, the Hantush-Jacob equation for a leaky confined aquifer, Hantush 's modified leaky equation in which storage from a confining layer was considered, the Boulton 's delayed-yield equation. Additionally, a specific-capacity method of estimating transmissivity was used when only a single drawdown value was available. (USGS)

  14. 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

  15. 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.

  16. 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

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. 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

  4. Joint inversion of aquifer test, MRS, and TEM data

    NASA Astrophysics Data System (ADS)

    Vilhelmsen, Troels N.; Behroozmand, Ahmad A.; Christensen, Steen; Nielsen, Toke H.

    2014-05-01

    This paper presents two methods for joint inversion of aquifer test data, magnetic resonance sounding (MRS) data, and transient electromagnetic data acquired from a multilayer hydrogeological system. The link between the MRS model and the groundwater model is created by tying hydraulic conductivities (k) derived from MRS parameters to those of the groundwater model. Method 1 applies k estimated from MRS directly in the groundwater model, during the inversion. Method 2 on the other hand uses the petrophysical relation as a regularization constraint that only enforces k estimated for the groundwater model to be equal to MRS derived k to the extent that data can be fitted. Both methodologies can jointly calibrate parameters pertaining to the individual models as well as a parameter pertaining to the petrophysical relation. This allows the petrophysical relation to adapt to the local conditions during the inversion. The methods are tested using a synthetic data set as well as a field data set. In combination, the two case studies show that the joint methods can constrain the inversion to achieve estimates of k, decay times, and water contents for a leaky confined aquifer system. We show that the geophysical data can assist in determining otherwise insensitive k, and vice versa. Based on our experiments and results, we mainly advocate the future application of method 2 since this seems to produce the most reliable results, has a faster inversion runtime, and is applicable also for linking k of 3-D groundwater flow models to multiple MRS soundings.

  5. Introduction to hydromechanical well tests in fractured rock aquifers.

    PubMed

    Schweisinger, Todd; Svenson, Erik J; Murdoch, Lawrence C

    2009-01-01

    This article introduces hydromechanical well tests as a viable field method for characterizing fractured rock aquifers. These tests involve measuring and analyzing small displacements along with pressure transients. Recent developments in equipment and analyses have simplified hydromechanical well tests, and this article describes initial field results and interpretations during slug and constant-rate pumping tests conducted at a site underlain by fractured biotite gneiss in South Carolina. The field data are characterized by displacements of 0.3 microm to more than 10 microm during head changes up to 10 m. Displacements are a hysteretic function of hydraulic head in the wellbore, with displacements late in a well test always exceeding those at similar wellbore pressures early in the test. Displacement measurements show that hydraulic aperture changes during well tests, and both scaling analyses and field data suggest that T changed by a few percent per meter of drawdown during slug and pumping tests at our field site. Preliminary analyses suggest that displacement data can be used to improve estimates of storativity and to reduce nonuniqueness during hydraulic well tests involving single wells. PMID:18823402

  6. 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.

  7. 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.

  8. Mental alertness in response to hypoglycaemia in normal man: the effect of 12 hours and 72 hours of fasting.

    PubMed

    Fourest-Fontecave, S; Adamson, U; Lins, P E; Ekblom, B; Sandahl, C; Strand, L

    1987-01-01

    To study the influence of hypoglycaemia and starvation on mental functions eight healthy male students age 25-34 years with an ideal body mass of 99.9% +/- 2.5% (mean +/- SEM) were recruited. Hypoglycaemia was induced in random order by an insulin-glucose clamp technique (insulin: 2.4 mU/kg/min + glucose at variable rate) keeping the venous blood glucose at 2.2 mmol/l both after an overnight fast and after 72 h fasting. Mental alertness was assessed by measuring the recognition time, moving time and total reaction time to a visual signal and by a verbal mental clearness test and a synonym learning test during normo- as well as hypoglycaemia. Hypoglycaemia prolonged the total reaction time (p less than 0.05) and the time required for the mental clearness test (p less than 0.05). Compared with a control study performed at normoglycaemia the learning effect of the synonym test was reduced by hypoglycaemia. Fasting, which resulted in a body weight reduction of 2.6 +/- 0.3 kg and ketonuria prolonged the total reaction time (p less than 0.005) by increasing the moving time but did not affect the mental clearness test. When hypoglycaemia was preceded by 72 h fasting it did not increase the total reaction time, nor did it modify the mental clearness test. Moreover, the learning effect of the synonym test was less impaired. In conclusion, mental alertness was reduced by moderate hypoglycaemia after an overnight fast while similar hypoglycaemia did not reduce mental alertness after prolonged fasting. This may illustrate a decrease of the glucose dependency of the central nervous system during prolonged fasting. PMID:3315761

  9. Estimating Parameters of Aquifer Heterogeneity from Transient Pumping Test

    NASA Astrophysics Data System (ADS)

    Zech, Alraune; Müller, Sebastian; Attinger, Sabine

    2015-04-01

    We present a new method for interpreting drawdowns of transient pumping tests in heterogeneous porous media. The vast majority of natural aquifers are characterized by heterogeneity, which can be statistically represented by parameters such as geometric mean bar K, variance σ^2, and correlation length ℓ of hydraulic conductivity. Our method can be understood as extension of the effective well flow method [Zech et al., 2012] from steady state to transient pumping tests. It allows a direct parameter estimation of bar K, σ^2, ℓ from head measurements under well flow conditions. The method is based on a representative description of hydraulic conductivity for radial flow regimes K_CG. It was derived previously using the upscaling procedure Radial Coarse Graining in combination with log-normal hydraulic conductivity. A semi-analytical solution for the mean drawdown of transient pumping tests was derived by combining the upscaled solution for the radially adapted hydraulic conductivity K_CG and the groundwater flow equation under well flow conditions. The dependency of the drawdown solution on the statistical quantities of the porous medium allows us to inversely estimate bar K, σ^2, ℓ from pumping test data. We used an ensemble of transient pumping test simulations to verify the drawdown solution. We generated pumping tests in heterogeneous media for various values of the statistical parameters bar K, σ^2, ℓ and evaluated their impact on the drawdown behavior as well as on the temporal evolution. We further examined the impact of several aspects like the location of an observation well or the local conductivity at the pumping well on the drawdown behavior. Zech, A., C. L. Schneider, and S. Attinger, 2012, The Extended Thiem's solution: Including the impact of heterogeneity, Water Resour. Res., 48, W10535, doi:10.1029/2012WR011852.

  10. SIMPLIFIED ANALYSIS OF TWO-WELL TRACER TESTS IN STRATIFIED AQUIFERS

    EPA Science Inventory

    The paper illustrates several interesting effects of aquifer stratification on the results of two-well tracer tests by means of a simplified computer model. In the model, it is assumed that the aquifer is horizontal, confined, of constant thickness and porosity, and perfectly str...

  11. 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.

  12. 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.

  13. Protective effect of St. John's wort (Hypericum perforatum) extract on 72-hour sleep deprivation-induced anxiety-like behavior and oxidative damage in mice.

    PubMed

    Kumar, Anil; Singh, Anant

    2007-10-01

    Sleep disruption or poor quality of sleep is a common problem associated with depression. Antidepressant drugs have been reported to improve the quality of sleep and behavior. The present study was undertaken to explore the therapeutic potential of Hypericum perforatum (St. John's wort) on behavioral alterations and oxidative damage induced by sleep deprivation in mice. Male laca mice (n = 6 - 10 in each group) were sleep deprived for 72 hours using the grid suspended over water method. Standardized Hypericum perforatum extract and imipramine were administered for five days, starting two days before sleep deprivation. Alterations in body weight, motor activity, anxiety like behavior (mirror chamber, plus maze, zero maze) and oxidative stress parameters (reduced glutathione, catalase, lipid peroxidation and nitrite levels) were observed after drug treatment in sleep-deprived animals. 72-hour sleep deprivation significantly altered body weight, locomotor activity and produced anxiety-like behavior and oxidative damage (depleted reduced glutathione, catalase activity and increased lipid peroxidation and nitrite activity) as compared to the naïve (placed on sawdust) animals (P < 0.05). Treatment with either St. John's wort (200 and 400 mg/kg, P. O.) or with imipramine (10 mg/kg, I. P.) significantly improved body weight, locomotor activity, antianxiety and antioxidant effect as compared to the control group (sleep deprived) (P < 0.05). Co-administration of John's wort (200 mg/kg, P. O.) with imipramine (10 mg/kg, I. P.) further improved body weight, locomotor activity, antianxiety effect as well as reduced oxidative damage in sleep-deprived animal as compared to their effect per se (P < 0.05). The present study suggests that there is therapeutic potential of St. John's wort in the management of sleep deprivation-induced anxiety-like behavior and oxidative damage. PMID:17918039

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Use of a Canal-Drawdown Test to Calculate the Specific Yield of the Biscayne Aquifer

    NASA Astrophysics Data System (ADS)

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

    2002-05-01

    Data from a large-scale canal-drawdown test were used to estimate the specific yield (sy) of the Biscayne Aquifer. The drawdown test involved dropping the water level in a nearby 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. Specific yield values computed from drawdown at individual piezometers ranged from 0.050 to 0.57, with a mean value of 0.15. The mean value for specific yield was incorporated into a large scale two-dimensional numerical MODFLOW-based groundwater flow model and predictions of head were made during a 183-day period at 4 wells located 337-2546 m from the canal. There was good agreement between the 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 for a highly transmissive limestone aquifer, in which execution of a traditional pump test would be impractical. 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 groundwater hydrology of the Biscayne Aquifer.

  20. 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

  1. 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

  2. Inhibition of SULT4A1 expression induces up-regulation of phototransduction gene expression in 72-hour postfertilization zebrafish larvae.

    PubMed

    Crittenden, Frank; Thomas, Holly; Ethen, Cheryl M; Wu, Zhengliang L; Chen, Dongquan; Kraft, Timothy W; Parant, John M; Falany, Charles N

    2014-05-01

    Sulfotransferase (SULT) 4A1 is an orphan enzyme that shares distinct structure and sequence similarities with other cytosolic SULTs. SULT4A1 is primarily expressed in neuronal tissue and is also the most conserved SULT, having been identified in every vertebrate investigated to date. Certain haplotypes of the SULT4A1 gene are correlated with higher baseline psychopathology in schizophrenic patients, but no substrate or function for SULT4A1 has yet been identified despite its high level of sequence conservation. In this study, deep RNA sequencing was used to search for alterations in gene expression in 72-hour postfertilization zebrafish larvae following transient SULT4A1 knockdown (KD) utilizing splice blocking morpholino oligonucleotides. This study demonstrates that transient inhibition of SULT4A1 expression in developing zebrafish larvae results in the up-regulation of several genes involved in phototransduction. SULT4A1 KD was verified by immunoblot analysis and quantitative real-time polymerase chain reaction (qPCR). Gene regulation changes identified by deep RNA sequencing were validated by qPCR. This study is the first identification of a cellular process whose regulation appears to be associated with SULT4A1 expression. PMID:24553382

  3. Inhibition of SULT4A1 Expression Induces Up-Regulation of Phototransduction Gene Expression in 72-Hour Postfertilization Zebrafish Larvae

    PubMed Central

    Crittenden, Frank; Thomas, Holly; Ethen, Cheryl M.; Wu, Zhengliang L.; Chen, Dongquan; Kraft, Timothy W.; Parant, John M.

    2014-01-01

    Sulfotransferase (SULT) 4A1 is an orphan enzyme that shares distinct structure and sequence similarities with other cytosolic SULTs. SULT4A1 is primarily expressed in neuronal tissue and is also the most conserved SULT, having been identified in every vertebrate investigated to date. Certain haplotypes of the SULT4A1 gene are correlated with higher baseline psychopathology in schizophrenic patients, but no substrate or function for SULT4A1 has yet been identified despite its high level of sequence conservation. In this study, deep RNA sequencing was used to search for alterations in gene expression in 72-hour postfertilization zebrafish larvae following transient SULT4A1 knockdown (KD) utilizing splice blocking morpholino oligonucleotides. This study demonstrates that transient inhibition of SULT4A1 expression in developing zebrafish larvae results in the up-regulation of several genes involved in phototransduction. SULT4A1 KD was verified by immunoblot analysis and quantitative real-time polymerase chain reaction (qPCR). Gene regulation changes identified by deep RNA sequencing were validated by qPCR. This study is the first identification of a cellular process whose regulation appears to be associated with SULT4A1 expression. PMID:24553382

  4. Aquifer characterization using transient streaming potentials generated by flow during pumping tests - New developments

    NASA Astrophysics Data System (ADS)

    Malama, B.; Kuhlman, K. L.; Revil, A.

    2009-12-01

    Traditional methods of aquifer characterization, namely pumping and slug tests, provide the most direct way of measuring system state variables (hydraulic head) and estimating hydraulic parameters (hydraulic conductivity, specific storage and specific yield) of aquifers. Despite this significant advantage, such methods have some serious limitations: they can be laborious, expensive, are intusive and yield spatially sparse data. Hydrogeophysical methods offer some promise to overcome some of these limitations. We discuss recently developed semi-analytical solutions for transient streaming potentials associated with pumping tests conducted in homogeneous confined and unconfined aquifers. Using these solutions, data obtained from field tests conducted (a) in a confined aquifer at a site located near Montalto Uffugo, in the region of Calabria in Southern Italy, and (b) in an unconfined aquifer at the Boise Hydrogeophysical Research Site (BHRS) in Idaho, US. Estimates of hydraulic parameters that compare well to those obtained by traditional methods were obtained. Our work indicates that transient streaming potential data, collected at land surface, may be used to provide preliminary estimates of hydraulic aquifer properties quickly and cheaply.

  5. 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.

  6. 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

  7. 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)

  8. Using periodic analytic elements to analyze aquifer tests near surface waters

    NASA Astrophysics Data System (ADS)

    Kelson, Vic; Bakker, Mark

    2013-02-01

    In riverbank filtration (RBF), the objective is to indirectly pump water from a river into wells near the river, by inducing recharge through the river sediments. Design models must quantify the rate of induced infiltration from surface waters, which is often controlled by the hydraulic resistance between the surface water body and the aquifer. Traditional tools for aquifer-test analysis near surface streams have limited utility for directly estimating the resistance of a streambed or riverbed. The authors have developed software tools for aquifer test analysis using an analytic element model for periodically varying flow called Wigaem. The Wigaem code can explicitly represent the plan-view geometry of surface streams and the aquifer perimeter, including tributary streams when necessary. All boundary conditions in the model may vary periodically, including water levels in surface waters and pumping rates of wells in the simulation. A constant-discharge pumping test may be simulated by extending the pumping regime in time such that it becomes periodic and the total discharge during the period of simulation equals zero. Problems caused by the Gibbs phenomenon are reduced through application of a moving average filter, which makes Wigaem suitable for very general aquifer test problems. By calibrating the model to match observed water-level data, the model is used to estimate the transmissivity, storativity, and the entry resistance of surface waters, which are crucial for the design of RBF systems. This approach is applied to a site in central Illinois, United States.

  9. Compressed-air energy storage: Pittsfield aquifer field test

    SciTech Connect

    Bui, H.V.; Herzog, R.A.; Jacewicz, D.M.; Lange, G.R.; Scarpace, E.R.; Thomas, H.H. )

    1990-02-01

    This report documents the results of a comprehensive investigation into the practical feasibility for Compressed Air Energy Storage (CAES) in Porous Media. Natural gas porous media storage technology developed from seventy years of experience by the natural gas storage industry is applied to the investigation of CAES in porous media. A major objective of this investigation is the geologic characterization, deliverability prediction, and operations analysis of the Pittsfield CAES aquifer experiment, conducted in Pike County, Illinois during 1981--85 under EPRI/DOE sponsorship. Emphasis has been placed on applying accepted petroleum engineering concepts to the study of deliverability and on the characterization and quantification of oxygen losses which reportedly occurred at Pittsfield. Other objectives are to apply the natural gas underground storage technology and approach to a general study of CAES feasibility in porous media reservoirs, with emphasis on the practical risks and constraints of air storage in aquifer and depleted natural gas reservoirs, the effects of water on CAES operation, corrosion effects, and a review of air dehydration options.

  10. A semi-analytical solution for slug tests in an unconfined aquifer considering unsaturated flow

    NASA Astrophysics Data System (ADS)

    Sun, Hongbing

    2016-01-01

    A semi-analytical solution considering the vertical unsaturated flow is developed for groundwater flow in response to a slug test in an unconfined aquifer in Laplace space. The new solution incorporates the effects of partial penetrating, anisotropy, vertical unsaturated flow, and a moving water table boundary. Compared to the Kansas Geological Survey (KGS) model, the new solution can significantly improve the fittings of the modeled to the measured hydraulic heads at the late stage of slug tests in an unconfined aquifer, particularly when the slug well has a partially submerged screen and moisture drainage above the water table is significant. The radial hydraulic conductivities estimated with the new solution are comparable to those from the KGS, Bouwer and Rice, and Hvorslev methods. In addition, the new solution also can be used to examine the vertical conductivity, specific storage, specific yield, and the moisture retention parameters in an unconfined aquifer based on slug test data.

  11. 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

  12. 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.

  13. Hydrogeology and aquifer test on the San Andres-Glorieta Aquifer on the southwest part of the Zuni Indian Reservation, Cibola County, New Mexico

    USGS Publications Warehouse

    Crouch, T.M.

    1994-01-01

    A large-yield aquifer test of the confined San Andres-Glorieta aquifer was conducted in 1988 to estimate aquifer properties and evaluate the potential effects of large-scale development on the aquifer by pumping from a cave-fracture system on the southwest part of the Zuni Indian Reservation. The San Andres-Glorieta aquifer underlies the reservation and in much of the area is the only aquifer capable of yielding large volumes of water. Two observation wells were drilled 1.2 and 2.7 miles from the pumped well. Water-level responses were recorded at distances from 179 feet to about 5 miles from the pumped well at these and other wells and at Rainbow Spring. Water levels declined at all observation wells and Rainbow Spring in response to pumping for more than 10 days at about 2,580 gallons per minute. Drawdown after 9 days varied from about 4 feet at the pumped well to about 0.2 foot at the most distant observation well and Rainbow Spring. If pumping continued at the average rate as the first 9 days of the test, 2,540 gallons per minute, and aquifer response remained constant, Rainbow Spring would have nearly 2 feet of drawdown after 30 years, and probably would be accompanied by a reduction in springflow of about 65 percent, to about 210 gallons per minute. Water quality remained generally unchanged throughout the aquifer test and is practically the same as that of samples collected at well ZS-1 in 1984 and Rainbow Spring in 1979.

  14. 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

  15. 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.

  16. 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

  17. 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)

  18. 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.

  19. 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)

  20. 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.

  1. Stochastic inversion of sequential hydraulic tests for transient and highly permeable unconfined aquifer systems

    NASA Astrophysics Data System (ADS)

    Ni, C.-F.; Huang, Y.-J.; Yeh, T.-C. J.; Dong, J.-J.; Chen, J.-S.; Li, M.-H.

    2013-12-01

    A hydraulic tomography survey (HTS) is a conceptually improved technique that has been recognized to be efficient for estimating high-resolution aquifer parameters. Based on the concept of HTS, this study presents a modified stochastic inverse model for estimating hydraulic conductivity (K) and specific yield (Sy) in shallow and highly permeable unconfined aquifers. A well field with 15 fully screened wells was developed for the purpose of model implementations. In this study a synthetic example was first employed to assess the accuracy of the inverse model. We then implemented the model to field-scale, cross-hole injection tests in a shallow and highly permeable unconfined aquifer near the middle reach of the Wu River in central Taiwan. To assess the effect of constant head boundary conditions on the estimation results, two additional modeling domains were evaluated based on the same field data from the injection tests. Results for the synthetic example show that the modified inverse model can reproduce well the predefined geologic features of the unconfined aquifer. The inverse model can estimate accurately the ln K patterns and magnitudes. However, slightly fewer details of the ln Sy field are obtained due to the insensitivity of transient hydraulic stresses for specified sampling times. Model implementations of field-scale injection tests show that the model can estimate ln K and ln Sy fields with high spatial resolution. The estimated K and Sy values for the test site vary by one order of magnitude, indicating a relatively homogeneous aquifer for the tested well field. Results based on three different modeling domains show similar patterns and magnitudes of ln K and ln Sy near the well locations. This result suggests that the case with domain 40 m × 20 m should be sufficient for the injection tests at the well field.

  2. 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

  3. 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.

  4. The Impeller Meter for measuring aquifer permeability variations: Evaluation and comparison with other tests

    NASA Astrophysics Data System (ADS)

    Molz, Fred J.; Morin, Roger H.; Hess, Alfred E.; Melville, Joel G.; Güven, Oktay

    1989-07-01

    A knowledge of the variation of horizontal hydraulic conductivity with vertical position, K(z), is important in understanding the transport and dispersive properties of aquifers. Using an impeller meter to measure the discharge distribution in a screened well while pumping at a constant rate is a promising technique for obtaining the K(z) function. Such an application is described herein, and the resulting K(z) functions are compared with those obtained previously using tracer tests and multilevel slug tests. Impeller meter data were the most convenient to obtain, and tracer data the most difficult. The K(z) functions obtained by the three methods were not identical but quite similar overall. This similarity between both borehole tests and the larger-scale tracer test showed that nonstationary hydraulic conductivity trends, in a stochastic hydrologic sense, exist in the test aquifer. The impeller meter method was better able to detect the higher K layers than was the multilevel slug approach. Overall, the results suggest that a practical strategy for "fitting" impeller meter, tracer, or multilevel slug test data to a given aquifer is to use the selected testing procedure to obtain a dimensionless distribution and then a standard pumping test to measure . Combining both types of information enables dimensional values for K(z) to be calculated. In low permeability aquifers or near the bottom of a test well the fluid velocity due to pumping may be below the stall velocity of an impeller. Thus there is a definite need for the commercial development of more sensitive flow-measuring devices such as heat pulse flowmeters (Hess, 1986), which will extend the resolution of this field method.

  5. Heat tracer test in an alluvial aquifer: field experiment and inverse modelling

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

    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 a piezometer and monitoring the evolution of groundwater temperature and tracer concentration in the recovery well and in monitoring wells. To get insights in the 3D characteristics of the heat transport mechanisms, temperature data from a large number of observation wells distributed throughout the field site (space-filling arrangement) 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 was explained by the groundwater flow gradient on the site and heterogeneity of 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 the pilot point inverse approach, main preferential flow paths were delineated.

  6. 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.

  7. 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.

  8. Aquifer tests of the Navajo sandstone near Caineville, Wayne County, Utah

    USGS Publications Warehouse

    Hood, J.W.; Danielson, T.W.

    1979-01-01

    Ground water in the Navajo Sandstone near Caineville, Wayne County, Utah, was studied during 1975-77 as part of an investigation of water in bedrock in the lower Dirty Devil River basin area. The purpose of the study near Caineville was to determine the water-bearing properties of the Navajo by utilizing data obtained mainly during test drilling and aquifer testing by the Intermountain Power Project.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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

  16. 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)

  17. 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)

  18. 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.

  19. 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

  20. 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.

  1. 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)

  2. Active thermal tracer testing in a shallow aquifer of the Thur valley, Switzerland

    NASA Astrophysics Data System (ADS)

    Schweingruber, Mischa; Somogyvári, Márk; Bayer, Peter

    2015-04-01

    Tracer tests are one of the standard methods for investigating groundwater processes. Among the range of different test variants, using heat as a tracer has gained substantial interest during the last decade. Temperature measurements have become essential ingredients for example for characterization of river-aquifer interactions and in the field of geothermics. Much less attention than on natural temperature signals has been devoted to induced synthetic temperature signals, even though it is well known that temperature is an easy to measure, invisible but sensitive system property. Design, application and inversion of such active thermal tracer tests represent one focus of our work. We build up on the experience from related field experiments, where heated water was injected and the propagation of the generated thermal anomaly was monitored. In this presentation, we show the results from first field-testing in an alluvial aquifer at the Widen site in the Thur valley in Switzerland. The thermal evolution of groundwater was monitored in summer 2014 during and after several days of heated water injection. By this test, we want to derive insights into the prevailing hydraulic heterogeneity of the shallow aquifer at the site. The results are used for calibration of a two dimensional hydrogeological numerical model. With the calibrated hydraulic conductivity field, the experiment is simulated and the transient evolution of the heat plume is visualized. Hydraulic heterogeneity is identified as one main factor for lateral spreading of the heat plume. The most important result of the experiment is that the significance of the ambient flow field is very high and even with high pumping rates to establish forced gradient conditions its effect cannot be overridden. During the test, precious technical experience was gained, which will be beneficial for subsequent heat tracer applications. For example, the challenge of maintaining a constant injection rate and temperature could

  3. 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

  4. Application of three aquifer test methods for estimating hydraulic properties within the 100-N Area

    SciTech Connect

    Gilmore, T.J.; Spane, F.A. Jr.; Newcomer, D.R.; Sherwood, C.R.

    1992-12-01

    The purpose if this study was to better define the range of saturated horizontal hydraulic conductivities in the 100-N Area of the Hanford Site in southeastern Washington for use in a numerical groundwater model. Three methods were used for determining aquifer properties and are discussed within this report (1) reanalysis of past pumping test data using a pressure derivative method to identify the data in the radial flow regime for analysis by traditional graphical techniques, (2) sinusoidal analysis techniques described in Ferris that utilize water-table responses to river-level variations, and (3) the basic flow equation for groundwater.

  5. On the emergence of reciprocity gaps during interference pumping tests in unconfined aquifers

    NASA Astrophysics Data System (ADS)

    Delay, Frederick; Ackerer, Philippe; Belfort, Benjamin; Guadagnini, Alberto

    2012-09-01

    We present a theoretical analysis of the conditions under which reciprocity gaps between vertically-averaged (square) drawdowns can be observed during typical interference pumping tests performed in unconfined heterogeneous aquifers. This work expands on the analysis of Delay et al. [1] and indicates that reciprocity gaps between vertically-averaged heads monitored during two consecutive tests can be due to vertical trends in aquifer properties (i.e., hydraulic conductivity and specific storage). These are then reflected in the vertical averaging procedure which is performed within a screened borehole and give rise to different observed dynamics of the averaged system responses. Spatially distributed recharge reflecting drainage from the unsaturated region during pumping can also significantly contribute to non-reciprocal behavior, especially for large test durations. Our theoretical findings are then illustrated through a suite of numerical simulations under a variety of vertical distributions of hydraulic parameters and in the presence of saturated/unsaturated flow conditions. We conclude that proper identification of the causes underlying reciprocity gaps can significantly enhance our conceptual understanding of the system response to a sequence of pumping stresses.

  6. 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)

  7. Compressed-air energy storage field test using the aquifer at Pittsfield, Illinois

    SciTech Connect

    Istvan, J.A.; Pereira, J.C.; Roark, P.; Bakhtiari, H. )

    1990-02-01

    This report describes the design, construction, and operation of a field experiment to examine feasibility of full-scale compressed air energy storage (CAES) within aquifer reservoirs. A summary of data obtained and the conclusions from the field experiment are presented. Two injection/withdrawal wells, two instrument wells, and four logging/sampling wells were drilled and cored. Air was injected in the St. Peter Sandstone to create an air bubble which was cycled with ambient and elevated temperature air in the injection withdrawal pattern contemplated for CAES installations. At its peak content of 111.75 {times} 10{sup 6} scf, the air bubble was 30 ft thick at the I/W well area and reached 18 ft in thickness at a distance of 686 ft from the I/W well. Three post-test core wells were drilled and cored. The caprock, reservoir, and formation water were sampled and analyzed prior to and after exposure to compressed air and associated water. Samples of stored air were collected and analyzed. Items of interest were degree of liquid entrance into flowing well, effects in aquifer of increased air temperature, and changes in oxygen content of air. Prior to plugging and abandoning the well field, an additional well was drilled and cored, outside the air bubble. This work is part of the continuing research by EPRI to investigate the geochemical oxidation process. Reservoir engineering and utilization of geologic media for storing air has many complexities, but it has useable experience from successful natural gas storage. The design, construction, and testing at Pittsfield demonstrates that orientation toward useage of an aquifer air storage facility can be performed successfully. The disappearance of oxygen needs attention for seasonal storage of air but should not dampen enthusiasm for weekly or daily storage cycles.

  8. Cytotoxic effects in 3T3-L1 mouse and WI-38 human fibroblasts following 72 hour and 7 day exposures to commercial silica nanoparticles

    SciTech Connect

    Stępnik, Maciej; Arkusz, Joanna; Smok-Pieniążek, Anna; Bratek-Skicki, Anna; Salvati, Anna; Lynch, Iseult; Dawson, Kenneth A.; Gromadzińska, Jolanta; De Jong, Wim H.; Rydzyński, Konrad

    2012-08-15

    The potential toxic effects in murine (3T3-L1) and human (WI-38) fibroblast cell lines of commercially available silica nanoparticles (NPs), Ludox CL (nominal size 21 nm) and CL-X (nominal size of 30 nm) were investigated with particular attention to the effect over long exposure times (the tests were run after 72 h exposure up to 7 days). These two formulations differed in physico-chemical properties and showed different stabilities in the cell culture medium used for the experiments. Ludox CL silica NPs were found to be cytotoxic only at the higher concentrations to the WI-38 cells (WST-1 and LDH assays) but not to the 3T3-L1 cells, whereas the Ludox CL-X silica NPs, which were less stable over the 72 h exposure, were cytotoxic to both cell lines in both assays. In the clonogenic assay both silica NPs induced a concentration dependent decrease in the surviving fraction of 3T3-L1 cells, with the Ludox CL-X silica NPs being more cytotoxic. Cell cycle analysis showed a trend indicating alterations in both cell lines at different phases with both silica NPs tested. Buthionine sulfoximine (γ-glutamylcysteine synthetase inhibitor) combined with Ludox CL-X was found to induce a strong decrease in 3T3-L1 cell viability which was not observed for the WI-38 cell line. This study clearly indicates that longer exposure studies may give important insights on the impact of nanomaterials on cells. However, and especially when investigating nanoparticle effects after such long exposure, it is fundamental to include a detailed physico-chemical characterization of the nanoparticles and their dispersions over the time scale of the experiment, in order to be able to interpret eventual impacts on cells. -- Highlights: ► Ludox CL silica NPs are cytotoxic to WI-38 fibroblasts but not to 3T3-L1 fibroblasts. ► Ludox CL-X silica NPs are cytotoxic to both cell lines. ► In clonogenic assay both silica NPs induce cytotoxicity, higher for CL-X silica. ► Cell cycle analysis shows

  9. 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.

  10. Frequency dependent hydraulic properties estimated from oscillatory pumping tests in an unconfined aquifer

    NASA Astrophysics Data System (ADS)

    Rabinovich, Avinoam; Barrash, Warren; Cardiff, Michael; Hochstetler, David L.; Bakhos, Tania; Dagan, Gedeon; Kitanidis, Peter K.

    2015-12-01

    Oscillatory pumping tests were conducted at the Boise Hydrogeophysical Research Site. A periodic pressure signal is generated by pumping and injecting water into the aquifer consecutively and the pressure response is recorded at many points around the source. We present and analyze the data from the field test after applying Fourier analysis. We then match the data with a recently derived analytical solution for homogeneous formations to estimate the equivalent aquifer properties: conductivity K, specific storage Ss and specific yield Sy . The estimated values are shown to be in agreement with previous estimates conducted at this site. We observe variations in the estimated parameters with different oscillation periods of pumping. The trend of the parameters with changing period is discussed and compared to predictions by existing theory and laboratory experiments dealing with dynamic effective properties. It is shown that the results are qualitatively consistent with recent works on effective properties of formations of spatially variable properties in oscillatory flow. To grasp the impact of heterogeneity, a simple configuration is proposed, helping explain the observed increase in effective conductivity with decreasing period.

  11. 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.

  12. 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

  13. 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.

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

    NASA Astrophysics Data System (ADS)

    Weeks, E. P.

    2005-07-01

    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 m 2/d, and the minimum transmissivity 6.8 m 2/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.

  15. SIMULATIONS OF TWO-WELL TRACER TESTS IN STRATIFIED AQUIFERS AT THE CHALK RIVER AND THE MOBILE SITES

    EPA Science Inventory

    A simulation of two-well injection-withdrawal tracer tests in stratified granular aquifers is presented for two widely separated sites substantially different in terms of vertical distributions of hydraulic conductivity, well spacings, flow rates, test durations and tracer travel...

  16. THE QTRACER2 PROGRAM FOR TRACER-BREAKTHROUGH CURVE ANALYSIS FOR TRACER TESTS IN KARSTIC AQUIFERS AND OTHER HYDROLOGIC SYSTEMS

    EPA Science Inventory

    Tracer testing is generally regarded as the most reliable and efficient method of gathering surface and subsurface hydraulic information. This is especially true for karstic and fractured-rock aquifers. Qualitative tracing tests have been conventionally employed in most karst s...

  17. 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

  18. 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.

  19. Evaluation of pumping induced flow in observation wells during aquifer testing.

    PubMed

    Székely, Ferenc

    2013-01-01

    The vertical variation of drawdown around pumping wells generates an induced flow in the observation wells. A set of governing equations is presented to couple the drawdown variation and the vertical flux distribution in observation wells. A numerical example is performed to justify the governing equations and to verify the solution methods used by the simulation software WT. The example analyzes the effect of skin loss, wellbore storage, and vertical segmentation on the drawdown and induced flow in observation well during pumping. The evaluation of the Fairborn pumping test involves a vertically homogeneous and anisotropic water table aquifer, uniform well-face drawdown conditions in the pumping well and simulation of the drawdown evolution in the observation well with and without the effect of induced flow. The computer calibrations resulted in small differences between the measured and simulated drawdown curves. PMID:23198759

  20. 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)

  1. Integrating Tracer Test Data into Geostatistical Aquifer Characterization at the Hanford 300 Area

    NASA Astrophysics Data System (ADS)

    Chen, X.; Murakami, H.; Hahn, M. S.; Rockhold, M. L.; Vermeul, V.; Rubin, Y.

    2009-12-01

    Tracer testing under natural or forced gradient flow is an efficient method for characterizing subsurface properties, by monitoring and modeling the tracer plume migration in a heterogeneous aquifer. At the Hanford 300 area, non-reactive tracer experiments, in addition to constant-rate injection tests and electromagnetic borehole flow meter profiling, were conducted to characterize the heterogeneous hydraulic conductivity field at the site. The tracer was injected at a near-constant rate for 10 hours, and the tracer concentrations were monitored for 12 days in a network of observation wells. This work presents a Bayesian inverse modeling technique to infer the heterogeneity structure of the hydraulic conductivity in the saturated zone of the Hanford formation, using the breakthrough curves at various observation wells. Analytical or semi-analytical solutions for mass transport in divergent radial flow fields are adopted whenever possible to avoid expensive numerical forward simulations. Compared to the case conditioned on the constant-rate injection tests and electromagnetic borehole flow meter profiling, this study finds that the inclusion of tracer test data can improve the estimation of heterogeneity structure and reduce the prediction uncertainty of the solute transport at given locations. With the availability of observation wells at varying distances, we also investigate the worth of data in each observation well, which can be used to evaluate the effectiveness of current experimental setup and guide further data collection practices at the site.

  2. 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

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

    NASA Astrophysics Data System (ADS)

    Moench, Allen F.

    2008-06-01

    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.

  4. 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.

  5. 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

  6. Microbial succession and stimulation following a test well injection simulating CO2 leakage into shallow Newark Basin aquifers

    NASA Astrophysics Data System (ADS)

    Dueker, M.; Clauson, K.; Yang, Q.; Umemoto, K.; Seltzer, A. M.; Zakharova, N. V.; Matter, J. M.; Stute, M.; Takahashi, T.; Goldberg, D.; O'Mullan, G. D.

    2012-12-01

    Despite growing appreciation for the importance of microbes in altering geochemical reactions in the subsurface, the microbial response to geological carbon sequestration injections and the role of microbes in altering metal mobilization following leakage scenarios in shallow aquifers remain poorly constrained. A Newark Basin test well was utilized in field experiments to investigate patterns of microbial succession following injection of CO2 saturated water into isolated aquifer intervals. Additionally, laboratory mesocosm experiments, including microbially-active and inactive (autoclave sterilized) treatments, were used to constrain the microbial role in mineral dissolution, trace metal release, and gas production (e.g. hydrogen and methane). Hydrogen production was detected in both sterilized and unsterilized laboratory mesocosm treatments, indicating abiotic hydrogen production may occur following CO2 leakage, and methane production was detected in unsterilized, microbially active mesocosms. In field experiments, a decrease in pH following injection of CO2 saturated aquifer water was accompanied by mobilization of trace elements (e.g. Fe and Mn), the production of hydrogen gas, and increased bacterial cell concentrations. 16S ribosomal RNA clone libraries, from samples collected before and after the test well injection, were compared in an attempt 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 injection, including a decrease in Proteobacteria, and an increased presence of Firmicutes, Verrucomicrobia, Acidobacteria and other microbes associated with iron reducing and syntrophic metabolism. The concurrence of increased microbial cell concentration, and rapid microbial community succession, with increased concentrations of hydrogen gas suggests that abiotically produced hydrogen may serve as an ecologically-relevant energy

  7. 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

  8. Microbial stimulation and succession following a test well injection simulating CO2 leakage into a shallow Newark basin aquifer.

    PubMed

    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

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. 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

  14. CO2 Injection Test in a Shallow Aquifer: Monitoring via Use of Different Technologies

    NASA Astrophysics Data System (ADS)

    Lamert, H.; Dietrich, P.; Werban, U.; Steinbrueckner, D.; Schulz, A.; Peter, A.; Grossmann, J.; Beyer, M.

    2011-12-01

    A promising tool for the reduction of CO2 emissions into the atmosphere is CCS (Carbon Capture and Storage). However, the availability of efficient methods for the detection and monitoring of potential CO2 degassing is a prerequisite for CO2 sequestration as well as for the public acceptance of this controversially discussed technology in general. Before implementing the CCS technology, a sound risk assessment and monitoring strategy is absolutely necessary. The aim of the project is to emulate a CO2 leakage scenario by injecting gaseous CO2 into a shallow aquifer. This field study was performed at a former military air field over a period of ten days in March and April 2011. One of the main objectives is to develop and test different monitoring methods applied to controlled CO2 intrusion in a shallow groundwater system. Thirty-four installed monitoring wells, predominantly oriented to the main groundwater flow direction, allow the sampling of groundwater during the injection test. Gaseous CO2 injection into the groundwater causes increasing electric resistivity. The subsequent dissolution and dissociation processes lead, in general, to decreasing pH and increasing electric conductivity. Installed wells were equipped with electrodes at different depths to detect changes in electric resistivity in the underground. Initial results show significant breakthrough curves of the electric resistivity signal affected by the injected CO2. Groundwater samples were taken before, during and after the injection test to validate these data. Field parameters (pH, electric conductivity) and stable isotope data were compared with the measured geoelectric data. Thus, the electric resistivity changes can be clearly related to the geochemically changed groundwater caused by the injected CO2.

  15. Predicting the denitrification capacity of sandy aquifers from in situ measurements using push-pull 15N tracer tests

    NASA Astrophysics Data System (ADS)

    Eschenbach, W.; Well, R.; Walther, W.

    2015-04-01

    Knowledge about the spatial variability of in situ denitrification rates (Dr(in situ)) and their relation to the denitrification capacity in nitrate-contaminated aquifers is crucial to predict the development of groundwater quality. Therefore, 28 push-pull 15N tracer tests for the measurement of in situ denitrification rates were conducted in two sandy Pleistocene aquifers in northern Germany. The 15N analysis of denitrification-derived 15N-labelled N2 and N2O dissolved in water samples collected during the push-pull 15N tracer tests was performed using isotope ratio mass spectrometry (IRMS) in the lab and additionally for some tracer tests online in the field with a quadrupole membrane inlet mass spectrometer (MIMS) in order to test the feasibility of on-site real-time 15N analysis. Aquifer material from the same locations and depths as the push-pull injection points was incubated, and the initial and cumulative denitrification after 1 year of incubation (Dcum(365)) as well as the stock of reduced compounds (SRC) was compared with in situ measurements of denitrification. This was done to derive transfer functions suitable to predict Dcum(365) and SRC from Dr(in situ). Dr(in situ) ranged from 0 to 51.5 μg N kg-1 d-1. Denitrification rates derived from on-site isotope analysis using MIMS satisfactorily coincided with laboratory analysis by conventional IRMS, thus proving the feasibility of in situ analysis. Dr(in situ) was significantly higher in the sulfidic zone of both aquifers compared to the zone of non-sulfidic aquifer material. Overall, regressions between the Dcum(365) and SRC of the tested aquifer material with Dr(in situ) exhibited only a modest linear correlation for the full data set. However, the predictability of Dcum(365) and SRC from Dr(in situ) data clearly increased for aquifer samples from the zone of NO3--bearing groundwater. In the NO3--free aquifer zone, a lag phase of denitrification after NO3- injections was observed, which confounded the

  16. Predicting the denitrification capacity of sandy aquifers from in situ measurements using push-pull 15N tracer tests

    NASA Astrophysics Data System (ADS)

    Eschenbach, W.; Well, R.; Walther, W.

    2014-12-01

    Knowledge about the spatial variability of in situ denitrification rates (Dr(in situ)) and their relation to the denitrification capacity in nitrate-contaminated aquifers is crucial to predict the development of groundwater quality. Therefore, 28 push-pull 15N tracer tests for the measurement of in situ denitrification rates were conducted in two sandy Pleistocene aquifers in Northern Germany. The 15N analysis of denitrification derived 15N labelled N2 and N2O dissolved in water samples collected during the push-pull 15N tracer tests was performed by isotope ratio mass spectrometry (IRMS) in the lab and additionally for some tracer tests online in the field with a quadrupole membrane inlet mass spectrometer (MIMS), in order to test the feasibility of on-site real-time 15N analysis. Aquifer material from the same locations and depths as the push-pull injection points was incubated and the initial and cumulative denitrification after one year of incubation (Dcum(365)) as well as the stock of reduced compounds (SRC) was compared with in situ measurements of denitrification. This was done to derive transfer functions suitable to predict Dcum(365) and SRC from Dr(in situ). Dr(in situ) ranged from 0 to 51.5 μg N kg-1 d-1. Denitrification rates derived from on-site isotope analysis using membrane-inlet mass spectrometry satisfactorily coincided with laboratory analysis by conventional isotope ratio mass spectrometry, thus proving the feasibility of in situ analysis. Dr(in situ) was significantly higher in the sulphidic zone of both aquifers compared to the zone of non-sulphidic aquifer material. Overall, regressions between the Dcum(365) and SRC of the tested aquifer material with Dr(in situ) exhibited only a modest linear correlation for the full data set. But the predictability of Dcum(365) and SRC from Dr(in situ) data clearly increased for aquifer samples from the zone of NO3--bearing groundwater. In the NO3--free aquifer zone a lag phase of denitrification after NO3

  17. 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

  18. Inferring field-scale properties of a fractured aquifer from ground surface deformation during a well test

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    Fractured aquifers which bear valuable water resources are often difficult to characterize with classical hydrogeological tools due to their intrinsic heterogeneities. Here we implement ground surface deformation tools (tiltmetry and optical leveling) to monitor groundwater pressure changes induced by a classical hydraulic test at the Ploemeur observatory. By jointly analyzing complementary time constraining data (tilt) and spatially constraining data (vertical displacement), our results strongly suggest that the use of these surface deformation observations allows for estimating storativity and structural properties (dip, root depth, and lateral extension) of a large hydraulically active fracture, in good agreement with previous studies. Hence, we demonstrate that ground surface deformation is a useful addition to traditional hydrogeological techniques and opens possibilities for characterizing important large-scale properties of fractured aquifers with short-term well tests as a controlled forcing.

  19. Sequential hydraulic tests for transient and highly permeable unconfined aquifer systems - model development and field-scale implementation

    NASA Astrophysics Data System (ADS)

    Ni, C.-F.; Huang, Y.-J.; Dong, J.-J.; Yeh, T.-C. J.

    2015-12-01

    The transient hydraulic tomography survey (THTS) is a conceptually improved technique that efficiently estimates detailed variations in aquifer parameters. Based on the concept of the THTS, we developed a geostatistical inverse model to characterize saturated hydraulic conductivity (K) and the specific yield (Sy) in transient and unconfined aquifer systems. In this study, a synthetic example was first used to assess the accuracy of the developed inverse model. Multiple random K and Sy realizations with different variances of natural logarithm of K (lnK) were generated and systematically compared to evaluate the effects of joint inversion on K estimations. The model was implemented in field-scale, cross-hole injection tests in a shallow and highly permeable unconfined aquifer near the middle reaches of the Wu River in central Taiwan. To assess the effect of constant head boundary conditions on the estimation results, two additional modeling domains were evaluated on the basis of the same field data from the injection tests. The results of the synthetic example showed that the proposed inverse model can effectively reproduce the predefined K patterns and magnitudes. However, slightly less detail was obtained for the Sy field based on the sampling data from sequential transient hydraulic stresses. The joint inversion by using transient head observations could slightly decrease the accuracy of K estimations. The model implementation for field-scale injection tests showed that the model can estimate K and Sy fields with detailed spatial variations. Estimation results showed a relatively homogeneous aquifer for the tested well field. Results based on the three modeling domains showed similar patterns and magnitudes of K and Sy near the well locations. These results indicated that the THTS is relatively insensitive to artificially drawn boundary conditions even under transient conditions.

  20. 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.

  1. 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.

  2. Hydraulic characterisation of carbonate aquifers with pumping tests - comparison of analytical and numerical data evaluation methods

    NASA Astrophysics Data System (ADS)

    Baierl, M.; Kordilla, J.; Reimann, T.; Dörfliger, N.; Sauter, M.; Geyer, T.

    2012-04-01

    This work deals with the analysis of pumping tests in strongly heterogeneous media. Pumping tests were performed in the catchment area of the Lez spring (South of France), which is composed of carbonate rocks. Pumping rates for the different tests varied between 0.04 l/s - 0.7 l/s, i.e. the radius of influence of the cone of depression is small. The investigated boreholes are characterised by tight rocks, moderate fractures and karstified zones. The observed drawdown curves are clearly influenced by the rock characteristics. Single drawdown curves show S-shape character. Data evaluation was performed with the solution approaches of Theis (1935) and Gringarten-Ramey (1974), which are implemented in the employed software AQTESOLV (Pro 4.0). Parameters were varied in reliable data ranges with consideration of reported values in the literature. The Theis method analyses unsteady flow in homogeneous confined aquifers. The Gringarten-Ramey solution describes the drawdown in a well connected to a single horizontal fracture. The Theis curve fails to represent the characteristics for nearly all of the measured drawdown curves, while the Gringarten-Ramey method shows moderate graphical fits with a small residual sum of squares between fitted and observed drawdown curves. This highlights the importance of heterogeneities in the hydraulic parameter field at local scale. The determined hydraulic conductivities of the rock are in reasonable ranges varying between 1E-04 m/s and 1E-08 m/s. Wellbore skin effects need to be discussed further in detail. While the analytical solutions are only valid for specific geometrical and hydraulic configurations, numerical models can be applied to simulate pumping tests in complex heterogeneous media with different boundary conditions. For that reason, a two dimensional, axisymmetric numerical model, using COMSOL (Multiphysics 4.1), is set up. In a first step, the model is validated with the simulated curves from the analytical solutions under

  3. Imaging and characterization of facies heterogeneity in an alluvial aquifer using GPR full-waveform inversion and cone penetration tests

    NASA Astrophysics Data System (ADS)

    Gueting, Nils; Klotzsche, Anja; van der Kruk, Jan; Vanderborght, Jan; Vereecken, Harry; Englert, Andreas

    2015-05-01

    Spatially highly resolved mapping of aquifer heterogeneities is critical for the accurate prediction of groundwater flow and contaminant transport. Here, we demonstrate the value of using full-waveform inversion of crosshole ground penetrating radar (GPR) data for aquifer characterization. We analyze field data from the Krauthausen test site, where crosshole GPR data were acquired along a transect of 20 m length and 10 m depth. Densely spaced cone penetration tests (CPT), located close to the GPR transect, were used to validate and interpret the tomographic images obtained from GPR. A strong correlation was observed between CPT porosity logs and porosity estimates derived from GPR using the Complex Refractive Index Model (CRIM). A less pronounced correlation was observed between electrical conductivity data derived from GPR and CPT. Cluster analysis of the GPR data defined three different subsurface facies, which were found to correspond to sediments with different grain size and porosity. In conclusion, our study suggests that full-waveform inversion of crosshole GPR data followed by cluster analysis is an applicable approach to identify hydrogeological facies in alluvial aquifers and to map their architecture and connectivity. Such facies maps provide valuable information about the subsurface heterogeneity and can be used to construct geologically realistic subsurface models for numerical flow and transport prediction.

  4. A PROGRAM TO ANALYZE AQUIFER TEST DATA AND CHECK FOR VALIDITY WITH THE JACOB METHOD

    EPA Science Inventory

    The Jacob straight-line method of aquifer analysis deals with the late-time data and small radius of the Theis type curve which plot as a straight line if the drawdown data are plotted on an arithmetic scale and the time data on a logarithmic (base 10) scale. Correct analysis wit...

  5. Identifying aquifer type in fractured rock aquifers using harmonic analysis.

    PubMed

    Rahi, Khayyun A; Halihan, Todd

    2013-01-01

    Determining aquifer type, unconfined, semi-confined, or confined, by drilling or performing pumping tests has inherent problems (i.e., cost and complex field issues) while sometimes yielding inconclusive results. An improved method to cost-effectively determine aquifer type would be beneficial for hydraulic mapping of complex aquifer systems like fractured rock aquifers. Earth tides are known to influence water levels in wells penetrating confined aquifers or unconfined thick, low-porosity aquifers. Water-level fluctuations in wells tapping confined and unconfined aquifers are also influenced by changes in barometric pressure. Harmonic analyses of water-level fluctuations of a thick (~1000 m) carbonate aquifer located in south-central Oklahoma (Arbuckle-Simpson aquifer) were utilized in nine wells to identify aquifer type by evaluating the influence of earth tides and barometric-pressure variations using signal identification. On the basis of the results, portions of the aquifer responded hydraulically as each type of aquifer even though there was no significant variation in lithostratigraphy. The aquifer type was depth dependent with confined conditions becoming more prevalent with depth. The results demonstrate that harmonic analysis is an accurate and low-cost method to determine aquifer type. PMID:22463080

  6. 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

  7. A Systematic Comparison of Tidally Induced Water Pressure Changes with a Standard Aquifer Test to Infer Permeability

    NASA Astrophysics Data System (ADS)

    Allègre, V.; Brodsky, E. E.; Nale, S. M.; Johnson, N. M.

    2014-12-01

    The use of water level oscillations driven by earth tides is a technique which has been used to infer rock properties such as permeability and storage at the field scale. The tidal method is attractive because it provides passively estimated permeability time series, allows identification of dynamic changes over time, and measures a hard to access scale ranging from a meters to tens of meters. It consists of computing the phase shift between tidally induced water level changes measured in boreholes, and theoretical earth tide strains. This leads to an estimate of the transmissivity, from which permeability can be deduced. To our knowledge, it has not been compared to standard method, such as pumping test analysis.In this work, water level data monitored before, during, and after two constant rate pumping tests performed in a shallow fractured aquifer were used, at the Santa Susana Field Site in Southern California. The two tests were one to five months long, the recordings lasting approximately 6 months. Tidal frequency oscillations appearing in the measurements were used to get permeability at thirteen locations, some of the wells providing several isolated open screened intervals at depth. As a comparison, permeabilities were also estimated from the fit of two aquifer tests at both early and late stages, using Theis solution (Gringarten solution gives similar results). The simple Theis solution is selected because it includes assumptions consistent with the assumptions in the isotropic and homogeneous tidal solution. The values obtained from both methods are consistent. No significant relation between permeability and faults located in the vicinity of the wells was identified, however, we do observe some variations at depth. Furthermore, some variability is observed in permeability time series during the pumping phases. This study shows that tidal responses lead to a passive and accurate capture of the shallow aquifer properties.

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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

  13. A mini slug test method for determination of a local hydraulic conductivity of an unconfined sandy aquifer

    NASA Astrophysics Data System (ADS)

    Hinsby, Klaus; Bjerg, Poul L.; Andersen, Lars J.; Skov, Bent; Clausen, Erik V.

    1992-08-01

    A new and efficient mini slug test method for the determination of local hydraulic conductivities in unconfined sandy aquifers is developed. The slug test is performed in a small-diameter (1 inch) driven well with a 0.25 m screen just above the drive point. The screened drive point can be driven from level to level and thereby establish vertical profiles of the hydraulic conductivity. The head data from the test well are recorded with a 10 mm pressure transducer, and the initial head difference required is established by a small vacuum pump. The method described has provided 274 spatially distributed measurements of a local hydraulic conductivity at a tracer test site at Vejen, Denmark. The mini slug test results calculated by a modified Dax slug test analysing method, applying the elastic storativity in the Dax equations instead of the specific yield, are in good accordance with the results from two natural gradient tracer experiments performed at the test site. The original Dax, the Bouwer and Rice, and the Chirlin analysing methods all led to an underestimation of the effective hydraulic conductivity by a factor of more than 2, when compared with the tracer tests. In contrast the spherical flow model of Karasaki et al. overestimated the results of the tracer tests by approximately a factor 1.4. The Dax and the Cooper et al. methods, assuming only radial flow to the partially screened well, yielded a better approximation of the horizontal hydraulic conductivity, than the Chirlin method, which also considers axial flow. This fact is suggested to be a result of aquifer anisotropy, as a significant higher horizontal than vertical hydraulic conductivity may suppress the significance of the axial flow component.

  14. 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

  15. 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

  16. Analysis of aquifer tests conducted in boreholes USW WT-10, UE-25 WT No. 12, and USW SD-7, 1995-96, Yucca Mountain, Nevada

    SciTech Connect

    O`Brien, G.M.

    1997-09-01

    Single-borehole aquifer tests were conducted in three boreholes in the Yucca Mountain area between March 1995 and January 1996 to obtain estimates of borehole specific capacity and aquifer transmissivity. Analysis of aquifer testing in borehole USW SD-7 also resulted in an estimate of reservoir volume. Aquifer-test data were analyzed with the Cooper and Jacob straight-line method, two modified Theis nonequilibrium equation solutions, and a modified reservoir-limit solution. The highest estimates of transmissivity were in borehole USW WT-10, completed in the Topopah Spring Tuff. Mean transmissivity, based on the results of three drawdown tests, was 1,600 meters squared per day. Mean specific capacity in borehole USW WT-10 after 5 hours of pumping was 1,100 meters squared per day, and was estimated to be 740 meters squared per day after 24 hours of pumping. Aquifer testing in borehole UE-25 WT No. 12 appeared to be significantly affected by well losses. A mean transmissivity of 7 meters squared per day was obtained on the basis of analysis of three drawdown tests in borehole UE-25 WT No. 12. Mean specific capacity in borehole UE-25 WT No. 12, after 24 hours of pumping, was 7 meters squared per day. Borehole UE-25 WT No. 12 seemed to be producing water from fractures that could provide only a limited amount of water to the borehole.

  17. 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

  18. Specific yield as determined by type-curve analysis of aquifer-test data

    USGS Publications Warehouse

    Moench, Allen F.

    1994-01-01

    The commonly used analytical solution developed by Neuman for a homogeneous, water-table aquifer assumes that the drainage of pores in the zone above the water table due to lowering of the water table occurs instantaneously. Noninstantaneous drainage of pores in the unsaturated zone accounts for the finding that both type-curve analysis and volume-balance calculations yield values of specific yield that are slightly less than those obtained from laboratory column-drainage experiments. It may also account for a slight underestimation of vertical hydraulic conductivity as obtained by type-curve analysis.

  19. 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)

  20. 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

  1. 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

  2. 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

  3. 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

  4. 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.

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

    USGS Publications Warehouse

    Zhan, X.; Butler, J.J., Jr.

    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.

  6. 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

  7. 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)

  8. 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.

  9. Use of penetrative investigations and pumping test data to revise large scale maps of surficial aquifers in northern Cattaraugus County, New York

    SciTech Connect

    Smith, P.; Goodman, W.; Cole, R.; Abbott, L. )

    1993-03-01

    A penetrative investigation of the Carpenter Brook Valley (CBV) in northern Cattaraugus County, New York provided a sedimentologic and hydrologic database for comparison with regional valley-fill aquifers. CBV trends east-west and is tributary to the larger Ischua Creek Valley (ICV) which contains a small primary aquifer. A regional map (1:250,000) by Miller (1988) depicts the CBV as containing a throughgoing surficial aquifer of unknown potential. In the CBV, discrete deposits have been evaluated for aquifer potential using sustainable well yields, transmissivities, and size. These parameters are then compared against known local aquifer-grade deposits in the ICV. The results demonstrate that there are no throughgoing surficial aquifers in CBV. The uppermost surficial unit is a clayey mottled silt (ave. K = 10[sup [minus]6] cm/sec). Based upon current soil conservation service data, the lower water-bearing unit forms discontinuous pockets that are generally less than 0.31 mi[sup 2] in area. The average saturated thickness for this flow till unit is less than 15 ft. Average transmissivity based upon pumping test data is approximately 3.96 [times] 10[sup [minus]1] ft[sup 2]/min. Average specific capacity from step-drawdown data is approximately 7--25 gpm/ft. The ICV primary aquifer is greater than 5 mi[sup 2] in area and supports several municipal supply wells. The Villages of Machias and Franklinville have wells with saturated thicknesses of approximately 40 and 76 ft; municipal supply wells exhibit specific capacities of 310 and 188 gpm/ft, respectively. This study demonstrates the need for detailed penetrative investigations to augment regional-scale maps. Regional scale maps are not intended for site-specific investigations and cannot be solely relied upon for interpretations of surficial deposits and their hydraulic performance.

  10. 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.

  11. 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...

  12. 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

  13. A New Model Incorporating Variably Saturated Flow That Accounts for Capillary-Fringe Elongation in Unconfined-Aquifer Tests

    NASA Astrophysics Data System (ADS)

    Moench, A. F.

    2006-12-01

    A seven-day, 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 included detailed water content in the unsaturated zone through time and space and drawdown in the saturated zone. The water content data reveal downward translation of the soil-moisture profiles and simultaneous elongations of the capillary fringe. Estimates of capillary-fringe thicknesses made use of use of model-calculated water-table elevations. Using drawdown data only, parameter estimation with a numerical model that solves Richards' equation for fluid flow and uses Brooks and Corey functional relations to represent unsaturated-zone characteristics yielded simulated drawdowns in the saturated zone that compared favorably with measured drawdowns. However, the modeled soil-moisture profile bore no resemblance to measured soil- moisture profiles and the model did not accurately simulate capillary-fringe elongation. I propose a modified model that largely decouples the Brooks and Corey soil-moisture and relative hydraulic conductivity functions by using two pore-size distribution functions, one for each functional relation. With the proposed model the general shape of the measured soil-moisture profiles was reproduced, there were time-varying vertical extensions of the capillary fringe consistent with observations, and there was satisfactory agreement between simulated and measured drawdowns in the saturated zone. The model does not account for appreciable radial variations in the thickness of the capillary fringe. For example, in seven days of pumping the capillary fringe grew from 35 to 58 cm at a distance of 1 m and 41 to 50 cm at a distance of 20 m. The analysis shows that drawdown measurements in the saturated zone by themselves without supporting soil-moisture measurements are not sufficient to

  14. 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.

  15. MAINE AQUIFERS

    EPA Science Inventory

    AQFRS24 contains polygons of significant aquifers in Maine (glacial deposits that are a significant ground water resource) mapped at a scale 1:24,000. This statewide coverage was derived from aquifer boundaries delineated and digitized by the Maine Geological Survey from data com...

  16. 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.

  17. 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.

  18. Evaluation of the heat-storage capability of shallow aquifers using active heat tracer tests and Fiber-Optics Distributed-Temperature-Sensing

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

    In the course of the energy transition, geothermal energy storage and heat generation and cooling have proven to be environmental friendly alternatives to conventional energy. However, to ensure sustain usage, the heat transport behavior of aquifers and its distribution has to be studied. A tool to achieve this is the active heat tracer test, eg. Leaf et al. (2012). If active heat tracer tests are combined with in aquifer heat testing via electric heating-cables, eg. Liu et al. (2013), it is possible to observe heat transport and temperature signal decay without disturbing the original pressure field within the aquifer. In this field study a two channel High-Resolution-Fiber-Optic-Distributed-Temperature-Sensing and Pt100 were used to measure temperature signals within in two wells of 1.4 m distance, where the temperature difference was generated using a self regulating heating cable in the upstream well. High resolution Distributed-Temperature-Sensing measurements were achieved by coiling the fiber around screened plastic tubes. The upstream well was also used to observe heating (Δ Tmax approx. 24K) and temperature signal decay, while the downstream well was used to observe heat transport between both wells. The data was analyzed and compared to thermal conductivity of soil samples and Direct-Push (DP) Electrical-Conductivity-Logging and DP Hydraulic-Profiling results. The results show good agreement between DP data and temperature measurements proving the active heat tracer test is a suitable tool for providing reliable information on aquifer heat-storage capability. References Leaf, A.T., Hart, D.J., Bahr, J.M.: Active Thermal Tracer Tests for Improved Hydrostratigraphic Characterization. Ground Water, vol. 50, 2012 Liu, G., Knobbe, S., Butler, J.J.Jr.: Resolving centimeter-scale flows in aquifers and their hydrostratigraphic controls. Geophysical Research Letters, vol. 40, 2013

  19. Multispecies reactive tracer test in an aquifer with spatially variable chemical conditions, Cape Cod, Massachusetts: Dispersive transport of bromide and nickel

    USGS Publications Warehouse

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

    2002-01-01

    Dispersive transport of groundwater solutes was investigated as part of a multispecies reactive tracer test conducted under spatially variable chemical conditions in an unconfined, sewage-contaminated sand and gravel aquifer on Cape Cod, Massachusetts. Transport of the nonreactive tracer bromide (Br) reflected physical and hydrologic processes. Transport of the reactive tracer nickel (Ni) complexed with an organic ligand (NiEDTA) varied in response to pH and other chemical conditions within the aquifer. A loss of about 14% of the Ni mass was calculated from the distribution of tracers through time. This loss is consistent with reversible adsorption of NiEDTA onto the iron and aluminum oxyhydroxide coatings on the aquifer sediments. The Ni consistently lagged behind Br with a calculated retardation coefficient of 1.2. Longitudinal dispersivities reached constant values of 2.2 and 1.1 m for Br and Ni, respectively, by at least 69 m of travel. The smaller dispersivity for Ni possibly was due to nonlinear or spatially variant adsorption of NiEDTA. In the upper, uncontaminated zone of the aquifer, longitudinal dispersion of Ni was greater than that of Br early in the test as a result of reversible adsorption of NiEDTA. In general, transverse dispersivities were much smaller (horizontal: 1.4-1.5 ?? 10-2 m; vertical: 0.5-3.8 ?? 10-3 m) than the longitudinal dispersivities. The Br results are similar to those from a test conducted eight years earlier, suggesting that transport parameters are spatially stationary within the aquifer at the scale of 300 m covered by the spatially overlapping tests. A significant difference between the two tests was the travel distance (69 and 26 m) needed to reach a constant longitudinal dispersivity.

  20. 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.

  1. Development of a method for in situ measurement of denitrification in aquifers using 15N tracer tests and membrane inlet mass spectrometry

    NASA Astrophysics Data System (ADS)

    Eschenbach, W.; Well, R.; Flessa, H.; Walther, W.; Duijnisveld, W. H. M.

    2009-04-01

    In NO3- contaminated aquifers containing reduced compounds like organic carbon or sulfides, denitrification is an intense process. Its characterization is of interest because NO3- consump-tion improves water quality and N2O production can cause emission of this greenhouse gas to the atmosphere. Spatial distribution of NO3- and N2 produced by denitrification in groundwa-ter (excess N2) reflects the NO3- input as well as cumulative denitrification during aquifer pas-sage. Reaction progress (RP) at a given location, i.e. the relative consumption by denitrifica-tion of the NO3- that had been leached to the aquifers, characterizes the stage of the denitrifi-cation process. RP can be derived from the ratio between accumulated gaseous denitrification products and initial NO3- concentrations. The amount and spatial distribution of reduced com-pounds within denitrifying aquifers is not well known. Recent findings from parallel investi-gations on in situ denitrification and reactive compounds suggests that single-well 15N tracer tests might be suitable to characterize the stock of reduced compounds in aquifers (Konrad 2007). The overall objective of our studies is measure the spatial dynamics of denitrification within two sandy aquifers in northern Germany. This includes measurement of the actually occurring denitrification process. Moreover we want to determine the long-term denitrification potential which is governed by the stock of reactive material. Here we present a new approach for in situ-measurement of denitrification at monitoring wells using a combination of 15N-tracer push-pull experiments with in situ analysis of 15N-labled N2 and N2O using membrane inlet mass spectrometry (MIMS). We will present first results from a laboratory test with aquifer mesocosms using the MIMS method. In this test we supplemented aquifer material of two depths (2 and 7 m below surface) of a drinking water catchment in Northwest Germany with K15NO3 solution. After tracer application we

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

    USGS Publications Warehouse

    Bennett, Gordon D.; Ata-Ur-Rehman; 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.

  3. Estimating the hydrogeological parameters with the time-lapse resistivity imaging method during the pumping test in the unconfined aquifer

    NASA Astrophysics Data System (ADS)

    Chang, P.; Chang, L.; Chen, W.; Lu, H.

    2013-12-01

    We have conducted the time-lapse monitoring study during a single-well pumping test at the Pengtsuo site in Pingtung, Taiwan. Water level gauges were installed in the four wells, including P1, W1, O1 and O2, at the Pengtsuo site with different screen depths for the observation. We designed the pumping test to be executed in three phases, including the background, the stepwise pumping, and the continuous pumping phases. The survey line is crossing the four wells in order to compare the resistivity measurements with the water level records. Although the inverted resistivity images the vertical resistivity structures also reveal that the influences from the steel well casing at the well positions, the resistivity differences to the pre-pumping background show that the electrical resistivity imaging is able to resolve the change due to the dewatering from the pumping activity. We have found that the maximum resistivity increase took place at the locations in the vadose zone instead of the groundwater surface in the time-lapse images. The variation of the maximum resistivity differences in the vadose zone is consistent to the change of the groundwater level during the pumping test. We tried to use the drawdown from the time-lapse resistivity differences and the Theis equation for estimating the hydraulic transmissivity and the specific yield at the Pentsuo site. The estimated transmissivity and the specific yield is 1.01 m^2/min and 0.11, respectively. These values are close to those calculated from the measured groundwater level variations in the multiple wells. Therefore we concluded that the time-lapse resistivity imaging methods is able to help estimating and verify the transmissivity and the specific yield for the pumping test in the unconfined aquifer.

  4. Hydromechanical Pumping Test for the Joint Estimation of Hydraulic and Poroelastic Parameters in a Strongly Heterogeneous Glaciofluvial Aquifer

    NASA Astrophysics Data System (ADS)

    Illman, W. A.; Berg, S. J.

    2009-12-01

    The coupling of hydraulic and geomechanical processes is critical in predicting the magnitude of earthquakes, understanding the effect of hydrofracturing on groundwater resources, designing nuclear waste repositories, predicting land subsidence due to pumping and its reversal through water injection. Therefore, the knowledge of hydraulic and geomechanical properties of soil and rock (collectively known as hydromechanical properties) are crucial for understanding and predicting the behavior of complex geological systems. In this study, we jointly estimated hydraulic and poroelastic parameters (i.e., shear modulus) from pumping test data that exhibited “reverse water level fluctuations” known as the Noordbergum effect observed in aquitards adjacent to pumped aquifers. This was performed by coupling BIOT2, a finite element two-dimensional axisymmetric groundwater model that considers the poroelastic effect with the parameter estimation code PEST. We first tested our inverse approach using a synthetic data set with known parameters. Results of the synthetic case showed that for simple layered systems, it was possible to accurately reproduce both the hydraulic properties and the shear modulus. We then applied the inverse approach to a set of pumping test data collected at the North Campus Research Site (NCRS) located at the University of Waterloo in Ontario, Canada. Based on the knowledge of stratigraphy determined from cores, the field site was simplified for modeling purposes as a 5-layer system. Parameter estimation was performed using two different approaches: 1) matching data individually from each observation port, and 2) matching data simultaneously from all observation ports. The estimated hydraulic parameters and shear modulus were compared to those obtained from other means at the site and to those from the literature. This comparison yielded good agreement. The results collectively suggest that the joint estimation of hydraulic and poroelastic parameters

  5. Aquifer microcosms and in situ methods to test the fate and function of pollutant-degrading microorganisms

    SciTech Connect

    Krumme, M.L.; Dwyer, D. . Inst. fuer Biotechnologie); Thiem, S.M.; Tiedje, J.M. ); Smith, R.L. )

    1990-01-01

    Little information is available on groundwater microorganism ecology, and specifically on the distribution and biochemical diversity of pollution degrading microorganisms in the aquifer. While the introduction of nutrients and electron acceptors may stimulate natural populations to degrade certain pollutants, low levels of pollutants and complex mixtures of pollutants may require the modification of natural populations through selective pressure or by means of genetic engineering. This study was designed to address these issues by examining three populations of substituted aromatic compound-degraders: an indigenous population, an introduced degrader, and a genetically engineered microorganism (GEM) in the environmental conditions of a sand and gravel aquifer. The goals of this study are to gain field experience on the fate and function of pollutant-degrading organisms in the aquifer and to evaluate column microcosms and survival chambers as tools for predicting the fate and function of selected and modified bacterial strains as appropriate aquifer bioremediation agents. 6 figs.

  6. Assessment of Anaerobic Metabolic Activity and Microbial Diversity in a Petroleum-Contaminated Aquifer Using Push-Pull Tests in Combination With Molecular Tools and Stable Isotopes

    NASA Astrophysics Data System (ADS)

    Schroth, M. H.; Kleikemper, J.; Pombo, S. A.; Zeyer, J.

    2002-12-01

    In the past, studies on microbial communities in natural environments have typically focused on either their structure or on their metabolic function. However, linking structure and function is important for understanding microbial community dynamics, in particular in contaminated environments. We will present results of a novel combination of a hydrogeological field method (push-pull tests) with molecular tools and stable isotope analysis, which was employed to quantify anaerobic activities and associated microbial diversity in a petroleum-contaminated aquifer in Studen, Switzerland. Push-pull tests consisted of the injection of test solution containing a conservative tracer and reactants (electron acceptors, 13C-labeled carbon sources) into the aquifer anoxic zone. Following an incubation period, the test solution/groundwater mixture was extracted from the same location. Metabolic activities were computed from solute concentrations measured during extraction. Simultaneously, microbial diversity in sediment and groundwater was characterized by using fluorescence in situ hybridization (FISH), denaturing gradient gel electrophoresis (DGGE), as well as phospholipids fatty acid (PLFA) analysis in combination with 13C isotopic measurements. Results from DGGE analyses provided information on the general community structure before, during and after the tests, while FISH yielded information on active populations. Moreover, using 13C-labeling of microbial PLFA we were able to directly link carbon source assimilation in an aquifer to indigenous microorganisms while providing quantitative information on respective carbon source consumption.

  7. 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

  8. Simulations of Two-Well Tracer Tests in Stratified Aquifers at the Chalk River and the Mobile Sites

    NASA Astrophysics Data System (ADS)

    Huyakorn, Peter S.; Andersen, Peter F.; Molz, Fred J.; Güven, Oktay; Melville, Joel G.

    1986-07-01

    A simulation study of two-well injection-withdrawal tracer tests in stratified granular aquifers at two widely separated sites is presented. The first site is located near the Chalk River Nuclear Laboratories in Canada, and the second site is located in Mobile, Alabama. Field data and test conditions at these sites are substantially different in terms of vertical distributions of hydraulic conductivity, well spacings, flow rates, test durations, and tracer travel distances. Furthermore, the test at the Chalk River site was conducted in a recirculating mode, whereas the test at the Mobile site was conducted in a nonrecirculating mode. Simulations of these tests were performed in three dimensions using the curvilinear finite element model developed in the previous paper of this series. The simulations incorporated measured vertical variations in relative hydraulic conductivity and local dispersivity values that are small fractions (between 1/1000 and 1/100) of the spacing between the injection and the withdrawal wells. The local dispersivities are used to account for local hydrodynamic dispersion and are chosen independently so that they are not affected by the scales of the tests. Simulation results obtained from the model are presented. Interpretation of these results is made in conjunction with measured breakthrough curves at the withdrawal well and multilevel observation wells. For the Chalk River site, predicted and measured breakthrough curves at the withdrawal well are in good agreement over the earlier part of the test duration. Deviation of the field data from the model prediction occurs over the second part, where the predicted breakthrough curves show a declining trend but the field data plot does not. For the Mobile site, predicted and measured breakthrough curves at the withdrawal well show similar trends throughout the entire test duration and are in good agreement overall. Model predictions of the effect of hydraulic conductivity stratification on

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

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

    USGS Publications Warehouse

    Bohling, G.C.; Zhan, X.; Butler, J.J., Jr.; 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.

  16. 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)

  17. 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

  18. Using borehole geophysics and cross-borehole flow testing to define hydraulic connections between fracture zones in bedrock aquifers

    USGS Publications Warehouse

    Paillet, Frederick L.

    1993-01-01

    Nearly a decade of intensive geophysical logging at fractured rock hydrology research sites indicates that geophysical logs can be used to identify and characterize fractures intersecting boreholes. However, borehole-to-borehole flow tests indicate that only a few of the apparently open fractures found to intersect boreholes conduct flow under test conditions. This paper presents a systematic approach to fracture characterization designed to define the distribution of fractures along boreholes, relate the measured fracture distribution to structure and lithology of the rock mass, and define the nature of fracture flow paths across borehole arrays. Conventional electrical resistivity, gamma, and caliper logs are used to define lithology and large-scale structure. Borehole wall image logs obtained with the borehole televiewer are used to give the depth, orientation, and relative size of fractures in situ. High-resolution flowmeter measurements are used to identify fractures conducting flow in the rock mass adjacent to the boreholes. Changes in the flow field over time are used to characterize the hydraulic properties of fracture intersections between boreholes. Application of this approach to an array of 13 boreholes at the Mirror Lake, New Hamsphire site demonstrates that the transient flow analysis can be used to distinguish between fractures communicating with each other between observation boreholes, and those that are hydraulically isolated from each other in the surrounding rock mass. The Mirror Lake results also demonstrate that the method is sensitive to the effects of boreholes on the hydraulic properties of the fractured-rock aquifer. Experiments conducted before and after the drilling of additional boreholes in the array and before and after installation of packers in existing boreholes demonstrate that the presence of new boreholes or the inflation of packers in existing boreholes has a large effect on the measured hydraulic properties of the rock mass

  19. Analysing the capabilities and limitations of tracer tests in stream-aquifer systems

    USGS Publications Warehouse

    Wagner, B.J.; Harvey, J.W.

    2001-01-01

    The goal of this study was to identify the limitations that apply when we couple conservative-tracer injection with reactive solute sampling to identify the transport and reaction processes active in a stream. Our methodology applies Monte Carlo uncertainty analysis to assess the ability of the tracer approach to identify the governing transport and reaction processes for a wide range of stream-solute transport and reaction scenarios likely to be encountered in high-gradient streams. Our analyses identified dimensionless factors that define the capabilities and limitations of the tracer approach. These factors provide a framework for comparing and contrasting alternative tracer test designs.

  20. 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.

  1. 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.

  2. A dye-tracing test as an aid to studying karst development at an artesian limestone sub-aquifer: Zagros Zone, Iran

    NASA Astrophysics Data System (ADS)

    Mohammadi, Zargham; Raeisi, Ezzatollah; Zare, Mohammad

    2007-04-01

    A dye-tracing test is employed to study the karst development and flow regime at an artesian limestone sub-aquifer, the Khersan3 Dam site, Zagros Zone, Iran. Tracer breakthrough curves showed an early dominant peak followed by a pronounced tailing effect. The peak concentration was a response to induced pressure during dye injection. The results suggest that the dye was pushed into the small pores and fissures around the injection point during dye injection. Hence, the dye moved out as a result of matrix and fissure diffusive processes and created a long pronounced tailing. The maximum flow velocity in the upper artesian sub-aquifer ranged from 0.97 to 2.9 m/h. However, the mean tracer velocity ranged from 0.19 to 0.51 m/h based on the mean residence tracer time; consequently, the flow regime in the artesian sub-aquifer was determined to be mainly diffusive. The results reveal (1) a low hydraulic gradient from upstream of the dam axis to downstream; consequently, there is no considerable flow; (2) poor karst development and diffuse flow at the tracing test area; (3) a discharge zone at a location downstream of the dam axis which is the main terminal of general flow direction at the dam site.

  3. A field control release test for assessing plausibility of dissolved CO2 measurements for CO2 leakage detection in a shallow aquifer

    NASA Astrophysics Data System (ADS)

    Yang, C.; Delgado, J.; Philips, S. B.; Mickler, P. J.; Guzman, N.

    2013-12-01

    Detecting Co2 leakage signals in the shallow aquifer is one of the most changing issues because of high variability in groundwater chemistry and also interactions among CO2, aquifer materials and groundwater. This study presents a novel technology for detecting CO2 leakage by measuring dissolved CO2 in groundwater using an optical CO2 sensor. The control release test was conducted in the field laboratory, Brackenridge Field Lab where shallow aquifer is unconfined with bedrock at the depth of 6 m below surface. Several groundwater wells were drilled and screened at depths from 3 m to 6 m. Fiber optic distributed sensors for dissolved CO2 monitoring were installed in a well bore and connected to a computer for automatically measuring dissolved CO2 gas in groundwater for every 30 seconds. CO2 gas was bubbled into a well bore for about two hours and then was stopped. In addition, Nabr solution was added to the wellbore and Br was used as a tracer. Groundwater samples were collected periodically from the well for measuring groundwater pH, titrating alkalinity and analyzing DIC and concentrations of major ions. A reactive transport model by considering water-rock-CO2 interactions was used to simulate the control release test. Both field and modeling results show that dissolved CO2 measurements with an optical Co2 sensor can be used for detecting CO2 leakage in groundwater.

  4. Characterization of leaky faults: Study of water flow in aquifer-fault-aquifer systems

    NASA Astrophysics Data System (ADS)

    Shan, Chao; Javandel, Iraj; Witherspoon, Paul A.

    Leaky faults provide important flow paths for fluids to move underground. It is often necessary to characterize such faults in engineering projects such as deep well injection of waste liquids, underground natural gas storage, and radioactive waste isolation. To provide this characterization, analytical solutions are presented for groundwater flow through saturated aquifer-fault-aquifer systems assuming that both the aquifers and the fault are homogeneous and that the fault has an insignificant effect on aquifer hydraulic properties. Three different conditions are considered: (1) drawdown in the unpumped aquifer is negligibly small; (2) drawdown in the unpumped aquifer is significant, and the two aquifers have the same diffusivity; and (3) drawdown in the unpumped aquifer is significant, and the two aquifers have different diffusivities. Methods are presented to determine the fault transmissivity from pumping test data.

  5. 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.

  6. 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...

  7. 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)

  8. 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.

  9. 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

  10. 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

  11. 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

  12. 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.

  13. 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

  14. Assessing hydraulic connections across a complex sequence of volcanic rocks-Analysis of U-20 WW multiple-well aquifer test, Pahute Mesa, Nevada National Security Site, Nevada

    USGS Publications Warehouse

    Garcia, C. Amanda; Fenelon, Joseph M.; Halford, Keith J.; Reiner, Steven R.; Laczniak, Randell J.

    2011-01-01

    Groundwater beneath Pahute Mesa flows through a complexly layered sequence of volcanic rock aquifers and confining units that have been faulted into distinct structural blocks. Hydraulic property estimates of rocks and structures in this flow system are necessary to assess radionuclide migration near underground nuclear testing areas. The U.S. Geological Survey (USGS) used a 12 month (October 1, 2008-October 1, 2009) intermittent pumping schedule of well U-20 WW and continuously monitored water levels in observation wells ER-20-6 #3, UE-20bh 1, and U-20bg as a multi-well aquifer test to evaluate hydraulic connections across structural blocks, bulk hydraulic properties of volcanic rocks, and the hydraulic significance of a major fault. Measured water levels were approximated using synthetic water levels generated from an analytical model. Synthetic water levels are a summation of environmental water-level fluctuations and a Theis (1935) transform of the pumping signal from flow rate to water-level change. Drawdown was estimated by summing residual differences between measured and synthetic water levels and the Theis-transformed pumping signal from April to September 2009. Drawdown estimates were used in a three-dimensional numerical model to estimate hydraulic properties of distinct aquifers, confining units, and a major fault. A maximum water-level drawdown of nearly 0.4 foot in well UE-20bh 1, which is more than 1 mile from the pumping well, was detected across a major fault. Drawdown estimates in the observation well nearest to (ER-20-6 #3, less than 1 mile) and within the same structural block as the pumping well were less than detection (-6 per foot, respectively, and transmissivity estimates range from 1,200 to 3,600 feet squared per day. Sensitivity analyses indicate that the major fault is hydraulically similar to the permeable host rock and connects flow between structural blocks.

  15. 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

  16. Assessing the effect of natural attenuation on oxygen consumption processes in a sewage-contaminated aquifer by use of a natural-gradient tracer test

    NASA Astrophysics Data System (ADS)

    Mathisen, P. P.; Kent, D. B.; Smith, R. L.; Barber, L. B.; Harvey, R. W.; Metge, D. W.; Hess, K. M.; Leblanc, D. R.; Koch, J. C.

    2003-12-01

    Processes associated with aquifer restoration subsequent to cessation of treated-sewage loading in a sand and gravel aquifer are being investigated at the USGS Toxic Substances Hydrology Site on Cape Cod, MA. Restoration has been slow because of significant oxygen depletion resulting from biogeochemical processes associated with residual sorbed pools of organic carbon, ammonium, and reduced metals in the aquifer. The in situ interaction of the physical, chemical, and biological processes governing oxygen consumption was examined by using a natural-gradient tracer test in fall 2001, 6 years after sewage disposal had been discontinued. Ground water with a high dissolved oxygen (DO) concentration was withdrawn from an uncontaminated zone of the aquifer and re-injected with a conservative tracer, bromide, into an anoxic zone directly below a former sewage-effluent disposal bed where Fe and sulfide concentrations were below detection and the DO was less than 5 uM. An injection with negligible ammonium, a nitrate concentration of 22 uM, and DO of approximately 260 uM was maintained at approximately 15 L/hr for a period of 75 days. An array of multi-level samplers (MLS), placed at distances ranging from 1 to 7 m down-gradient from the injection well, was sampled prior to and throughout the 75-day injection, and during a 25-day period after the injection. Water samples from the MLS were analyzed for DO and a variety of aqueous constituents. The DO decreased from approximately 260 uM to 210 uM over 7 m of transport, indicating the presence of rate-limited oxygen consumption. An increase in nitrate from 22 to approximately 36 uM indicated the presence of rate-limited ammonium oxidation. However, this ammonium oxidation was not sufficient to account for all of the DO consumption. Further characterization of these processes was accomplished by use of PHREEQC, a one-dimensional, geochemical reactive transport model. The 1D model is based on an ion association model for aqueous

  17. 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.

  18. 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.

  19. 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

  20. 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

  1. BIODEGRADATION OF AROMATIC HYDROCARBONS BY AQUIFER MICROORGANISMS UNDER DENITRIFYING CONDITIONS

    EPA Science Inventory

    Laboratory tests were conducted to evaluate whether denitrification would be a suitable alternative for biorestoration of an aquifer contaminated with JP-4 jet fuel. icrocosms were prepared from uncontaminated and contaminated aquifer material, amended with nitrate, nutrients, an...

  2. 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

  3. Rate-limited U(VI) desorption during a small-scale tracer test in a heterogeneous uranium-contaminated aquifer

    NASA Astrophysics Data System (ADS)

    Fox, Patricia M.; Davis, James A.; Hay, Michael B.; Conrad, Mark E.; Campbell, Kate M.; Williams, Kenneth H.; Long, Philip E.

    2012-05-01

    A tracer test was performed at the Rifle Integrated Field Research Challenge site to assess the effect of addition of bicarbonate on U(VI) desorption from contaminated sediments in the aquifer and to compare equilibrium and rate-limited reactive transport model descriptions of mass transfer limitations on desorption. The tracer test consisted of injection of a 37 mM NaHCO3solution containing conservative tracers followed by down-gradient sampling of groundwater at various elevations and distances from the point of injection. Breakthrough curves show that dissolved U(VI) concentrations increased 1.2-2.6-fold above background levels, resulting from increases in bicarbonate alkalinity (from injectate solution) and Ca concentrations (from cation exchange). In general, more U(VI) was mobilized in shallower zones of the aquifer, where finer-grained sediments and higher solid phase U content were found compared to deeper zones. An equilibrium-based reactive transport model incorporating a laboratory-based surface complexation model derived from the same location predicted the general trends in dissolved U(VI) during the tracer test but greatly overpredicted the concentrations of U(VI), indicating that the system was not at equilibrium. Inclusion of a multirate mass transfer model successfully simulated the nonequilibrium desorption behavior of U(VI). Local sediment properties such as sediment texture (weight percent <2 mm), surface area, cation exchange capacity, and adsorbed U(VI) were heterogeneous at the meter scale, and it was important to incorporate these values into model parameters in order to produce accurate simulations.

  4. 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

  5. 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.

  6. 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

  7. 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

  8. 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.

  9. 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

  10. 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

  11. 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

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. Fast vertical movement of groundwater at the borehole in volcanic confined aquifer detected from point-dilution test with multi-level observations

    NASA Astrophysics Data System (ADS)

    Kim, Y.; Han, B.; Kim, K.; Koh, K.; Park, K.

    2007-12-01

    A point-dilution tracer test was performed at a Seokwang well field, one of the pulbic water supply system for southwestern part of Jeju island, South Korea. Seokwang well field is located at the elevation of about 180 m above mean sea level with gentle tilted surface topography to southwest direction. Based on the geological columnar section of supply well no. 3, Seokwang well field area is consisted of Basalt, tuff, clinker, and soil layer. various types of basalt such as trachy basalt, feldspar augite basalt, feldspar basalt and soil layers occurred overlapping each other and clinker zone act as permeable aquifer whereas tuff act as impermeable confining layer. 20 cubic meter's tracer solution as NaCl is injected through pipe at the depth of 170 m below top of the casing using pump and the EC breakthroughs at 18 different depths in the borehole BH3 are monitored using 5 CTD Divers and 13 series of EC sensors. The injected tracer solution transported vertically upward from the injection depth with slight downward movement of about 1 meter from the mouth of the injection pipe due to the force of inertia and gravity. The estimated vertical velocity of groundwater is 1.33 x 10-2 m/s (\\ 0.424 L/s )\\) , which was too fast to be detected by borehole logging using heat pulse type flowmeter.

  17. Geochemical and mineralogical characterization of the Arbuckle aquifer with laboratory flow cell experiments under supercritical conditions: Implications for CO2 sequestration

    NASA Astrophysics Data System (ADS)

    Barker, R. L.; Watney, W. L.; Bhattacharya, S.; Strazisar, B. R.; Kelly, L.; Ford, S. K.; Datta, S.

    2011-12-01

    The deep saline aquifer in south-central Kansas has been proposed as a potential site for geologic storage for CO2. Two wells (KGS 1-32 and 1-28) have been drilled to the basement to provide data for a site specific determination of the storage potential of the Arbuckle. The entirety of the Arbuckle (~4100-5100 ft) was cored to provide rock samples for description and flow cell experiments. Initial examination of the formation rocks show heterogeneity throughout the core samples that makes evident the need for careful examination of the formation to ensure accurate geochemical modeling in determining the storage capacity and extent of mineralization within injection rocks. The dominant mineralogy in the proposed CO2 injection zone is dolomitic limestone with sporadic large cherty nodules. Presence of extensive vugs and micro fractures are common at some depths. Thin section and XRD data have provided the specific mineral assemblage of each core plug. Drill stem test water samples were collected from 8 depths throughout the aquifer to describe the changing chemistry of water with depth. Initial chemical analysis show a hyper saline brine (range~50,000 - 190,000 TDS) dominated by Cl, Na and Ca. Elemental ratios of Cl:Br, Na:Cl and Ca:Sr are what is expected of a typical saline aquifer system. The swabbed water from 4995 to 5020 ft gave a constant pH of 4.76 for the entire period of pumping and field results show high sulfate concentrations (>200 mg/L). Laboratory experiments carried out at the National Energy Technology Laboratory at formation temperatures and pressures using formation core plugs and collected brine to identify the major reaction that can be anticipated when supercritical CO2 is in place. Formation brine is injected into the core plugs and supercritical CO2 is added thereafter. The effluent is collected as a time series of 1, 3, 6, 12, 18, 24, 32, 48 and 72 hours and analyzed for major, trace elements and anions by ICP-OES and IC to see the chemical

  18. 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.

  19. 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

  20. 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.

  1. Aquifer-nomenclature guidelines

    USGS Publications Warehouse

    Laney, R.L.; Davidson, C.B.

    1986-01-01

    Guidelines and recommendations for naming aquifers are presented to assist authors of geohydrological reports in the United States Geological Survey, Water Resources Division. The hierarchy of terms that is used for water- yielding rocks from largest to smallest is aquifer system, aquifer, and zone. If aquifers are named, the names should be derived from lithologic terms, rock-stratigraphic units, or geographic names. The following items are not recommended as sources of aquifer names: time-stratigraphic names, relative position, alphanumeric designations, depositional environment, depth of occurrence, acronyms, and hydrologic conditions. Confining units should not be named unless doing so clearly promotes understanding of a particular aquifer system. Sources of names for confining units are similar to those for aquifer names, i.e. lithologic terms, rock-stratigraphic units or geographic names. Examples of comparison charts and tables that are used to define the geohydrologic framework are included. Aquifers are defined in 11 hypothetical examples that characterize geohydrologic settings throughout the country. (Author 's abstract)

  2. 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

  3. 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.

  4. Biscayne aquifer, southeast Florida

    USGS Publications Warehouse

    Klein, Howard; Hull, John E.

    1978-01-01

    Peak daily pumpage from the highly permeable, unconfined Biscayne aquifer for public water-supply systems in southeast Florida in 1975 was about 500 million gallons. Another 165 million gallons was withdrawn daily for irrigation. Recharge to the aquifer is primarily by local rainfall. Discharge is by evapotranspiration, canal drainage, coastal seepage, and pumping. Pollutants can enter the aquifer by direct infiltration from land surface or controlled canals, septic-tank and other drainfields, drainage wells, and solid-waste dumps. Most of the pollutants are concentrated in the upper 20 to 30 feet of the aquifer; public supply wells generally range in depth from about 75 to 150 feet. Dilution, dispersion, and adsorption tend to reduce the concentrations. Seasonal heavy rainfall and canal discharge accelerate ground-water circulation, thereby tending to dilute and flush upper zones of the aquifer. The ultimate fate of pollutants in the aquifer is the ocean, although some may be adsorbed by the aquifer materials en route to the ocean, and some are diverted to pumping wells. (Woodard-USGS)

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. 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

  1. 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

  2. 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

  3. 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.

  4. 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.

  5. IDAHO AQUIFER TYPES

    EPA Science Inventory

    Five aquifer types are presented: Unconsolidated alluvium, Snake River Plain alluvium, Snake River Plain basalt, Columbia River basalt, Sedimentary / volcanic rock. Should only be used for page-sized maps of state, due to the very generalized source materials & digitizing proce...

  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. 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.

  8. 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.

  9. Diffusivity of a glacial-outwash aquifer by the floodwave- response technique.

    USGS Publications Warehouse

    Reynolds, R.J.

    1987-01-01

    Aquifer diffusivity (transmissivity divided by storage coefficient) was calculated for three sites near Cortland, New York from water-level fluctuations induced by rises in stream stage. Response data were analyzed through use of a one-dimensional floodwave-response model to calculate the theoretical head response in the aquifer generated by a floodwave in the stream, and then matched to the observed head response. This method of calculating aquifer diffusivity is relatively inexpensive compared to standard aquifer tests and is effective in glacial-valley fill aquifers that are hydraulically connected to a major stream or river.-from Author

  10. 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.

  11. Hydrogeology of the middle Wilcox aquifer system in Mississippi

    SciTech Connect

    Taylor, R.E.; Arthur, J.K. )

    1992-01-01

    A study has been performed to provide water resource planners and managers with hydrogeologic data on the predominantly undeveloped middle Wilcox aquifer system in Mississippi, and to describe its potential as an alternative source of water. The principal source of recharge to the middle Wilcox aquifer system is from precipitation in the outcrop area, a crescent-shaped belt extending from north to east, and dipping west to southwest. Most of the water that percolates into the ground is lost by evapotranspiration or groundwater discharge to local streams. Locally, the rate and direction of groundwater movement is controlled by the hydraulic conductivity of the sand bed and by withdrawal from wells. The potentiometric surface of the aquifer was mapped to represent the approximate altitude of water levels in wells screened in the middle Wilcox aquifer system in 1983. Near some pumping centers in and near the recharge area, water-level declines in recent years have been in the range of about 0.5 to 1.0 ft/yr. The aquifer system is capable of yielding 100-500 gpm from large wells; however, the availability of freshwater at shallower depths has limited the development of this aquifer system farther downdip, and results of aquifer tests are sparse. Groundwater in the outcrop area of the aquifer system generally is of a mixed, calcium-sodium bicarbonate type. There is a general trend of increasing pH values and concentrations of dissolved sodium, bicarbonate, nitrate, and iron with increasing depth. Typically, water in the middle Wilcox aquifer system has concentrations much smaller than the recommended limits for drinking water for nitrate, sulfate, and fluoride. Water from this aquifer system is generally suitable for most uses.

  12. 40 CFR 85.2233 - Steady state test equipment calibrations, adjustments, and quality control-EPA 91.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... for HC, CO, and CO2 and must continually compensate for changes in barometric pressure. Calibration...-point calibration within 72 hours before each test, unless changes in barometric pressure are... tolerance range. The pressure in the sample cell must be the same with the calibration gas flowing...

  13. 40 CFR 85.2233 - Steady state test equipment calibrations, adjustments, and quality control-EPA 91.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... for HC, CO, and CO2 and must continually compensate for changes in barometric pressure. Calibration...-point calibration within 72 hours before each test, unless changes in barometric pressure are... tolerance range. The pressure in the sample cell must be the same with the calibration gas flowing...

  14. 40 CFR 85.2233 - Steady state test equipment calibrations, adjustments, and quality control-EPA 91.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... for HC, CO, and CO2 and must continually compensate for changes in barometric pressure. Calibration...-point calibration within 72 hours before each test, unless changes in barometric pressure are... tolerance range. The pressure in the sample cell must be the same with the calibration gas flowing...

  15. EPA - NEW ENGLAND SOLE SOURCE AQUIFERS

    EPA Science Inventory

    This coverage contains boundaries of EPA-approved sole source aquifers. Sole source aquifers are defined as an aquifer designated as the sole or principal source of drinking water for a given aquifer service area; that is, an aquifer which is needed to supply 50% or more of the ...

  16. 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.

  17. 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

  18. 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

  19. 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)

  20. 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. PMID:16556198

  1. 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.

  2. 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.

  3. QTRACER PROGRAM FOR TRACER-BREAKTHROUGH CURVE ANALYSIS FOR KARST AND FRACTURED-ROCK AQUIFERS

    EPA Science Inventory

    Tracer tests are generally regarded as being the most reliable and efficient means of gathering subsurface hydraulic information. This is true for all types of aquifers, but especially so for karst and fractured-rock aquifers. Qualitative tracing tests have been conventionally em...

  4. 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.

  5. 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

  6. 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

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  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 147.2554 - 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...

  13. 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...

  14. 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...

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. 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...

  16. 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...

  17. 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

  18. 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.

  19. 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.

  20. 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...

  1. 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 ...

  2. 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.

  3. Hydrogeologic characterization of a fractured granitic rock aquifer, Raymond, California

    SciTech Connect

    Cohen, A.J.B.

    1993-10-01

    The hydrogeologic properties of a shallow, fractured granitic rock aquifer in the foothills of the Sierra Nevada, California were investigated via the analysis of borehole geophysical logs and pumping tests. The drawdowns produced during these tests are not indicative of any simple conceptual aquifer model, and borehole logs show that the granite is intensely fractured. These observations are suggestive of a complex fracture-flow geometry which is extremely difficult to decipher. However, through the measurement of orientations of individual subsurface fractures from acoustic televiewer logs, and correlation between particular fractures and electrical resistivity and thermal-pulse flowmeter logs, it was found that the aquifer is, in general, comprised of two subhorizontal and nearly parallel zones of unloading fractures. Downhole flowmeter measurements taken in several wells provide further evidence for the inferred dual-layer structure of the aquifer, as well as yield quantitative measures of the contribution of flow from each zone. Analysis of drawdowns in pumped wells reveals that there are zones of relatively high transmissivity immediately around them. It was found that these properties, as well as a nearby zone of lower transmissivity, can account for their observed drawdowns. A numerical model was constructed to test whether these major heterogeneities could also account for the drawdowns in observation wells. This stepwise analysis of both the geophysical and hydrological data resulted in the formulation of a conceptual model of the aquifer which is consistent with observations, and which can account for its behavior when subjected to pumping.

  4. SOLE SOURCE AQUIFER BOUNDARY DATA

    EPA Science Inventory

    There are 7 polygons representing 6 individual sole source aquifer boundaries and one streamflow source area in California, Arizona, and Nevada. Various efforts were combined to create the final product, which represents the Federal Register boundary description. Sole source aqu...

  5. 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.

  6. 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

  7. 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.

  8. 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

  9. 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.

  10. 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

  11. Analysis of multicomopnent groundwater flow in karst aquifer by CFC, tritium, tracer test and modelling, case study at Skaistkalnes vicinity, Latvia

    NASA Astrophysics Data System (ADS)

    Bikshe, Janis; Babre, Alise; Delina, Aija; Popovs, Konrads

    2014-05-01

    Groundwater in karst environments tends to have difficulties to distinguish multiple flows if several sources of water are present. Skaistkalne vicinity faces with such situation where old groundwater, fresh groundwater and inflow from river Iecava occurs. Attempts were made to distinguish groundwater residence time of multiple components of water applying CFC and tritium dating techniques supplied by tracer test and numerical model of study area. Study area covers territory between two rivers Iecava and Memele with water level difference of 7 meters and horizontal distance of 2.2 kilometres between both. Study area consists of karst affected Devonian gypsum and carbonaceous rocks covered by Quaternary low to high permeable deposits. Confined groundwater at depth of 10-25 meters where analysed by CFC's and tritium. At this depth groundwater exhibits anoxic reducing environment that has caused degradation of CFC's at similar degree in all samples. Taking it into account, mean residence time based on CFC piston flow model is 22 - 42 years and 28 - 34 years based on binary mixing model. Tritium results show signs of incensement of groundwater residence time towards discharge area. CFC combined with tritium proved increased vertical velocity in middle part between the rivers likely caused by hydrogeological window in Quaternary deposits created by karst processes. Numerical model (Delina et al. 2012) was applied and calculations yielded groundwater flow velocity rate at 0.3 - 1 m/day in area between the rivers. Investigation of CFC data resulted in possible groundwater flow rate of at a minimum of 0.2 m/day although it's not applicable to all sampled wells due to specific hydrogeological conditions. Tracer test was made between the rivers in order to distinguish main water flow paths and flow velocity. Results showed that very high permeable conduits connect rivers and karst lakes with velocity rates of 800 - 1300 m/day. Complex investigation leads to conclude that

  12. Hydrogeology and ground-water flow in the Memphis and Fort Pillow aquifers in the Memphis area, Tennessee

    USGS Publications Warehouse

    Brahana, J.V.; Broshears, R.E.

    2001-01-01

    On the basis of known hydrogeology of the Memphis and Fort Pillow aquifers in the Memphis area, a three-layer, finite-difference numerical model was constructed and calibrated as the primary tool to refine understanding of flow in the aquifers. The model was calibrated and tested for accuracy in simulating measured heads for nine periods of transient flow from 1886-1985. Testing and sensitivity analyses indicated that the model accurately simulated observed heads areally as well as through time. The study indicates that the flow system is currently dominated by the distribution of pumping in relation to the distribution of areally variable confining units. Current withdrawal of about 200 million gallons per day has altered the prepumping flow paths, and effectively captured most of the water flowing through the aquifers. Ground-water flow is controlled by the altitude and location of sources of recharge and discharge, and by the hydraulic characteristics of the hydrogeologic units. Leakage between the Fort Pillow aquifer and Memphis aquifer, and between the Memphis aquifer and the water-table aquifers (alluvium and fluvial deposits) is a major component of the hydrologic budget. The study indicates that more than 50 percent of the water withdrawn from the Memphis aquifer in 1980 is derived from vertical leakage across confining units, and the leakage from the shallow aquifer (potential source of contamination) is not uniformly distributed. Simulated leakage was concentrated along the upper reaches of the Wolf and Loosahatchie Rivers, along the upper reaches of Nonconnah Creek, and the surficial aquifer of the Mississippi River alluvial plain. These simulations are supported by the geologic and geophysical evidence suggesting relatively thin or sandy confining units in these general locations. Because water from surficial aquifers is inferior in quality and more susceptible to contamination than water in the deeper aquifers, high rates of leakage to the Memphis

  13. 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

  14. 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

  15. Modelling perched river recharge to the Wairau aquifer, New Zealand

    NASA Astrophysics Data System (ADS)

    Wöhling, Thomas; Gosses, Moritz; Wilson, Scott; Davidson, Peter

    2015-04-01

    The Wairau Aquifer in Marlborough, New Zealand, consists of coarse, high-conductive alluvial gravels and is almost exclusively recharged by surface water from the braided Wairau River. Recent experimental evidence suggests that the river is perched in the upstream recharge region of the aquifer. The aquifer serves as the major drinking water resource for the city of Blenheim and the surrounding settlements on the Wairau Plain and thus is a key natural resource for the region. To ensure the sustainable management of the resource, it is essential to better understand the limits and the mechanics of the recharge mechanism. One efficient way to test hypotheses of the mechanisms for river-groundwater exchange fluxes between the Wairau river and aquifer is by data integration into numerical models that mimic the flow regime of the coupled hydrological system. For that purpose, a Modflow model for the Wairau Aquifer was to set up and calibrated under summer conditions when the flow in the river is low and the aquifer is most vulnerable to over-allocation. The model is constrained by knowledge about the hydrogeological settings as well as observations of groundwater levels, river and spring flow gaugings, and analysis of aquifer pumping tests. Both historic and more recent concurrent river flow measurements under low flow conditions suggest that approximately 7-8 m³/s is recharged into the aquifer along the upper and middle reaches, at least partly under perched conditions. At the eastern side of the aquifer, a small proportion of that water flows back into the river, whereas a greater proportion emerges in springs. Spring creek is the largest spring with an estimated mean flow of 4.0 m³/s. This flow rate is vulnerable to an excessive decline in groundwater levels. The simulations with the calibrated flow model fit well to the observations of current mean groundwater heads as well as to mean Wairau river and Spring creek flows. Modeling results suggest a large spatial

  16. 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

  17. Estimation of effective hydrogeological parameters in heterogeneous and anisotropic aquifers

    NASA Astrophysics Data System (ADS)

    Lin, Hsien-Tsung; Tan, Yih-Chi; Chen, Chu-Hui; Yu, Hwa-Lung; Wu, Shih-Ching; Ke, Kai-Yuan

    2010-07-01

    SummaryObtaining reasonable hydrological input parameters is a key challenge in groundwater modeling. Analysis of temporal evolution during pump-induced drawdown is one common approach used to estimate the effective transmissivity and storage coefficients in a heterogeneous aquifer. In this study, we propose a Modified Tabu search Method (MTM), an improvement drawn from an alliance between the Tabu Search (TS) and the Adjoint State Method (ASM) developed by Tan et al. (2008). The latter is employed to estimate effective parameters for anisotropic, heterogeneous aquifers. MTM is validated by several numerical pumping tests. Comparisons are made to other well-known techniques, such as the type-curve method (TCM) and the straight-line method (SLM), to provide insight into the challenge of determining the most effective parameter for an anisotropic, heterogeneous aquifer. The results reveal that MTM can efficiently obtain the best representative and effective aquifer parameters in terms of the least mean square errors of the drawdown estimations. The use of MTM may involve less artificial errors than occur with TCM and SLM, and lead to better solutions. Therefore, effective transmissivity is more likely to be comprised of the geometric mean of all transmissivities within the cone of depression based on a precise estimation of MTM. Further investigation into the applicability of MTM shows that a higher level of heterogeneity in an aquifer can induce an uncertainty in estimations, while the changes in correlation length will affect the accuracy of MTM only once the degree of heterogeneity has also risen.

  18. 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. PMID:26849338

  19. 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.

  20. 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; ...

  1. A numerical investigation to illustrate the consequences of hydraulic connections between granular and fractured-rock aquifers

    NASA Astrophysics Data System (ADS)

    Chesnaux, Romain; Rafini, Silvain; Elliott, Annie-Pier

    2012-12-01

    Natural or artificial hydraulic connections between a granular aquifer in contact with a fractured-rock aquifer can have significant physical and chemical impacts at both a local and a regional scale. In this study, numerical simulations are conducted in order to illustrate the hydrogeological consequences of such hydraulic relationships. The numerical investigation, based on a conceptual model, focuses on the effects of the hydraulic connections when conducting a pumping test in a well that is set into a granular confined aquifer overlying a fractured-rock aquifer which presents a few fractures directly connected to the granular aquifer. It is illustrated that when interpreting the pumping test with the conventional methods consisting of plotting the drawdown versus time, a bias is introduced on the estimation of the transmissivity of the granular aquifer due to groundwater flowing from the fractured-rock aquifer via connecting fractures. However, it is underlined that plotting drawdown log-derivative versus time helps to diagnose the existence of these hydraulic relationships and therefore avoids committing a bias on the transmissivity estimation of the granular aquifer. Numerical simulation results also illustrate that hydraulic connections between the two aquifers can have significant impacts on the hydrogeochemical signature of the granular aquifer under investigation.

  2. 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...

  3. 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.

  4. 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.

  5. Transmissivity estimation for highly heterogeneous aquifers: comparison of three methods applied to the Edwards Aquifer, Texas, USA

    NASA Astrophysics Data System (ADS)

    Painter, Scott L.; Woodbury, Allan D.; Jiang, Yefang

    2007-03-01

    Obtaining reliable hydrological input parameters is a key challenge in groundwater modeling. Although many quantitative characterization techniques exist, experience applying these techniques to highly heterogeneous real-world aquifers is limited. Three geostatistical characterization techniques are applied to the Edwards Aquifer, a limestone aquifer in south-central Texas, USA, for the purposes of quantifying the performance in an 88,000-cell groundwater model. The first method is a simple kriging of existing hydraulic conductivity data developed primarily from single-well tests. The second method involves numerical upscaling to the grid-block scale, followed by cokriging the grid-block conductivity. In the third method, the results of the second method are used to establish the prior distribution for a Bayesian updating calculation. Results of kriging alone are biased towards low values and fail to reproduce hydraulic heads or spring flows. The upscaling/cokriging approach removes most of the systematic bias. The Bayesian update reduced the mean residual by more than a factor of 10, to 6 m, approximately 2.5% of the total head variation in the aquifer. This agreement demonstrates the utility of automatic calibration techniques based on formal statistical approaches and lends further support for using the Bayesian updating approach for highly heterogeneous aquifers.

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  11. 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

  12. 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)

  13. Aquifer data from four wells in the Mendenhall Valley near Juneau, Alaska

    USGS Publications Warehouse

    Balding, G.O.; Dearborn, L.L.

    1982-01-01

    This report summarizes data collected during drilling and testing of four wells in Mendenhall Valley, an area being developed as a suburb of Juneau, Alaska. Previous studies indicated that the glacial deposits on the east side of the valley had the potential for producing the large quantities of water needed for a community water supply. The drilling defined an upper aquifer between the water table and a depth of 215 feet and a lower aquifer below 252 feet. The testing did not define the storage coefficient or transmissivity of the upper aquifer. Drawdowns within 20 feet of the test well were less than 12 feet when the pumping rate was 300 gallons per minute. Greater pumping rates could be sustained in larger diameter wells having larger screened intervals in the upper aquifer but would produce greater drawdowns. The performance of the lower aquifer was not tested. Water in the upper aquifer is of adequate quality for drinking water, but may require treatment for iron; water from the lower aquifer is brackish. (USGS)

  14. Quasi-steady flow in sloping aquifers

    NASA Astrophysics Data System (ADS)

    Akylas, Evangelos; Gravanis, Elias; Koussis, Antonis D.

    2015-11-01

    Mass conservation links the storage S and the outflow Q of an aquifer. A relation between them (an S-Q relation) provides then a model governing the evolution of these quantities. In this work we construct an analytical quasi-steady state model which exploits the properties of the exact S-Q relation associated with steady state solutions of the Boussinesq equation for the sloping aquifer (that is, the Henderson and Wooding [1964] solutions). The model is derived by matching the asymptotic forms of the exact S-Q relation which arise for small and large values of the Henderson and Wooding parameter λ. These asymptotic forms provide a novel rederivation of well-known semiempirical S-Q relations of the form Q∝ S and Q∝ S2, and they lead to soluble quasi-steady state models. The quadratic asymptotic relation turns out to hold for surprisingly low values of λ. This characteristic and its formal properties allow smooth matching with the linear relation at λ=π2/4=2.47. The obtained model holds over the entire parameter space. An important characteristic of the model, stemming from its derivation, is that it involves only the geometric and hydraulic quantities present in the exact Boussinesq equation. The model is tested by best fitting four data sets from experiments simulating aquifer drainage. The derived curves for the drained volume are in excellent agreement with the data. The estimated values for k and n are also in overall very good agreement with their reference values.

  15. Inter-well field test to determine in-situ CO2 trapping in a deep saline aquifer: Modelling study of the effects of test design and geological parameters

    NASA Astrophysics Data System (ADS)

    Fagerlund, Fritjof; Niemi, Auli; Bensabat, Jacob; Shtivelman, Vladimir

    2013-04-01

    Trapping of CO2 by capillary effects and dissolution to groundwater is important for the security of geologically stored CO2 at many potential storage sites. Field tests are critical to measure the amount of CO2 which is effectively trapped in-situ and evaluate parameters that influence the trapping over larger scales and under influence of geological heterogeneity. Such well-monitored, small-scale field tests are being designed within the EU-FP7 MUSTANG project at the Heletz site, Israel. In an inter-well test, supercritical CO2 is injected in one well while fluids are produced from a second well. Several measurement techniques, including hydraulic, tracer, thermal and geophysical tests, are used to measure the trapping that occurs as the CO2 migrates through the formation between the two wells. The general outcome and success of the test depend on design options such as the distance between the wells and the injection/withdrawal rates and volumes, and also on site-specific geological parameters such as permeability, trapping parameters and heterogeneity. The objective of this study was to use numerical modelling to investigate how these design options and geological parameters affect the flow and transport processes in the formation and outcome of the test. The feasibility of the test depends e.g. on the amount of dissolution and residual trapping that occur, the pressure build-up in the formation and the time required to achieve complete trapping and perform the tests. Furthermore, the accuracy of the test depends on the ability of the different measurement techniques to quantify the trapping under different conditions. The results illustrate the sensitivity of the test outcome criteria to both the design options and the geological conditions. An efficient test design should take into account site-specific conditions so that design criteria are met and measurement accuracy and robustness are maximized.

  16. 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

  17. Hydrogeologic atlas of aquifers in Indiana

    USGS Publications Warehouse

    Fenelon, Joseph M.; Bobay, K.E.; Greeman, T.K.; Hoover, M.E.; Cohen, D.A.; Fowler, K.K.; Woodfield, M.C.; and Durbin, J. M.

    1994-01-01

    Aquifers in 12 water-management basins of Indiana are identified in a series of 104 hydrogeologic sections and 12 maps that show the thickness and configuration of aquifers. The vertical distribution of water-bearing units and a generalized potentiometric profile are shown along 3,500 miles of section lines that were constructed from drillers' logs of more than 4,200 wells. The horizontal scale of the sections is 1:125,000. Maps of aquifers showing the areal distribution of each aquifer type were drawn at a scale of 1:500,000. Unconsolidated aquifers are the most widely used aquifers in Indiana and include surficial, buried, and discontinuous layers of sand and gravel. Most of the surficial sand and gravel is in large outwash plains in northern Indiana and along the major rivers. Buried sand and gravel aquifers are interbedded with till deposits in much of the northern two-thirds of Indiana. Discontinuous sand and gravel deposits are present as isolated lenses, primarily in glaciated areas. The bedrock aquifers generally have lower yields than most of the sand and gravel aquifers; however, bedrock aquifers are areally widespread and are an important source of water. Bedrock aquifer types consist of carbonates; sandstones; complexly interbedded sandstones, siltstones, shales, limestones, and coals; and an upper weathered zone in low permeability rock. Carbonate aquifers underlie about one-half of Indiana and are the most productive of the bedrock aquifers. The other principal bedrock aquifer type, sandstone, underlies large areas in the southwestern one-fifth of Indiana. No aquifer is known to be present in the southeastern corner of Indiana.

  18. 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

  19. 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.

  20. Hydrogeochemical and mathematical analyses of aquifer intercommunication, Hanford Site, Washington state

    SciTech Connect

    Graham, M.J.

    1983-01-01

    The US Department of Energy Hanford Site in south-central Washington has served as an integrated nuclear facility since the early 1940s. Pleistocene postglacial flood waters and the ancestral Columbia River flowed through the center of the Hanford Site, carving erosional windows in the geologic unit that separates the two aquifers, thereby creating pathways for the migration to occur. A two fold research approach was applied to studying the problem: mathematical analyses of ground-water flow dynamics, and hydrogeochemical analyses of the ground waters. Data from tracer tests and water-level measurements in wells were used to define the ground-water flow system of the Rattlesnake Ridge aquifer. The hydrogeochemical data support the conceptual model of ground-water flow within the Rattlesnake aquifer. Interpretations of the various hydrogeochemical data indicate the same general pattern of mixing of unconfirmed aquifer waters in the Rattlesnake Ridge aquifer, resulting from aquifer intercommunication. Low levels (below drinking water standards) of tritium and iodine-129 in the Rattlesnake Ridge aquifer were identified in this mixing area. By applying a two-fold approach to the problem, a defensible conceptual model of ground-water flow and aquifer intercommunication within the study area was developed.

  1. Digital model of predevelopment flow in the Tertiary limestone (Floridan) aquifer system in West-Central Florida

    USGS Publications Warehouse

    Ryder, Paul D.

    1982-01-01

    A computer model was calibrated to approximate predevelopment flow conditions in a multilayered aquifer system in 10,600 square miles in west-central Floria. The lowermost aquifer, called the Floridan aquifer, is confined in most of the study area and consists of carbonate rocks ranging up to 1,300 feet thick. The Floridan aquifer is the chief source for large withdrawals and natural springflow in the study area. Daily springflows within the study area have averaged about 2.4 billion gallons. The secondary artesian and the surficial aquifers are much less permeable than the Floridan aquifer. Where they are present and have heads higher than those in the Floridan aquifer, they provide recharge to the Floridan. Initial estimates of recharge to the Floridan aquifer were from water-balance calculations for surface-water basins; initial estimates of transmissivity were from aquifer tests and flow-net analyses. The model was calibrated for the predevelopment era, wherein steady-state flow conditions were assumed. Calibrated transmissivities for the Floridan aquifer range from less than 15,000 to several million feet squared per day. Recharge to the system was about 3,700 cubic feet per second. About 90% was discharged as springflow, and 10% was upward leakage. (USGS)

  2. 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.

  3. 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.

  4. 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

  5. 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

  6. 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.

  7. 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

  8. Hydrology of aquifer systems in the Memphis area, Tennessee

    USGS Publications Warehouse

    Criner, James H.; Sun, P-C. P.; Nyman, Dale J.

    1964-01-01

    . The average rate of depletion of storage in each aquifer since pumping began is about 1 mgd. Most of the recharge to the '500-foot' and '1,400-foot' sands occurs in outcrop areas about 30-80 miles east of Memphis. Also, water leaks from the terrace deposits to the '500-foot' sand in some places, and there may be some leakage from streams where the confining clay is thin or is breached by faults or streams. The quality of water from both the principal aquifers is very good. Iron, carbon dioxide, and hydrogen sulfide are the only constituents found in undesirable quantities. Water from the terrace deposits is hard but generally contains less iron and carbon dioxide than water from either of the principal aquifers. The hydraulic characteristics of both aquifers were determined by pumping tests and by applying the knowledge of the geology o# the area; these characteristics indicate that the aquifers are capable of producing more water than is currently being pumped from them. The '500-foot' sand will produce more water per unit decline of water level than will the '1,400-foot' sand. There appears to be no reason why the development of water supplies from both aquifers should not continue, but well spacing will remain a factor which could affect future development. Greater well spacing will tend to prolong the useful life of a well and the aquifers.

  9. 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

  10. 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.

  11. 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

  12. 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

  13. 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

  14. 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.

  15. 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)

  16. The typology of Irish hard-rock aquifers based on an integrated hydrogeological and geophysical approach

    NASA Astrophysics Data System (ADS)

    Comte, Jean-Christophe; Cassidy, Rachel; Nitsche, Janka; Ofterdinger, Ulrich; Pilatova, Katarina; Flynn, Raymond

    2012-12-01

    Groundwater flow in hard-rock aquifers is strongly controlled by the characteristics and distribution of structural heterogeneity. A methodology for catchment-scale characterisation is presented, based on the integration of complementary, multi-scale hydrogeological, geophysical and geological approaches. This was applied to three contrasting catchments underlain by metamorphic rocks in the northern parts of Ireland (Republic of Ireland and Northern Ireland, UK). Cross-validated surface and borehole geophysical investigations confirm the discontinuous overburden, lithological compartmentalisation of the bedrock and important spatial variations of the weathered bedrock profiles at macro-scale. Fracture analysis suggests that the recent (Alpine) tectonic fabric exerts strong control on the internal aquifer structure at meso-scale, which is likely to impact on the anisotropy of aquifer properties. The combination of the interpretation of depth-specific hydraulic-test data with the structural information provided by geophysical tests allows characterisation of the hydrodynamic properties of the identified aquifer units. Regionally, the distribution of hydraulic conductivities can be described by inverse power laws specific to the aquifer litho-type. Observed groundwater flow directions reflect this multi-scale structure. The proposed integrated approach applies widely available investigative tools to identify key dominant structures controlling groundwater flow, characterising the aquifer type for each catchment and resolving the spatial distribution of relevant aquifer units and associated hydrodynamic parameters.

  17. 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)

  18. 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.

  19. 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.

  20. Estimation of Hydraulic Property of an Unconfined Aquifer by GPR

    NASA Astrophysics Data System (ADS)

    Lu, Qi; Sato, Motoyuki

    2007-06-01

    Controlled water productions were performed at a water source area of Ulaanbaatar city, Mongolia to evaluate the effectiveness of ground penetrating radar (GPR) for detecting and monitoring dynamic groundwater movements in the subsurface and for estimating the hydraulic properties of the aquifer. Field experiments in Ulaanbaatar were carried out in 2001 and 2002. GPR data were acquired using 100 MHz antennas. This paper reports the results of GPR methods to monitor the groundwater migration caused by the pumping operation and GPR’s potential ability to estimate hydraulic properties of the aquifer. The GPR data sets were acquired very carefully by locating the antenna position accurately. The residual trace shows a feature that is a combination of the water level reflections acquired at two different times in the pumping test. It helped to determine travel time and its effective reflection point from the top of the water saturated zone. The residual wavelet varies versus offset from the pumping well for a given residual image. Common midpoint (CMP) data and velocity analysis indicated the depth of the water table and the water content in the unsaturated and saturated zone. Combining hydrogeologic data with quantitative information yielded by GPR data, hydraulic properties of the aquifer could be estimated by assuming a hydraulic model. It was concluded that GPR can be successfully employed to monitor groundwater migration and to estimate hydraulic properties of the aquifer.

  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. Characterization of an island aquifer from tidal response

    NASA Astrophysics Data System (ADS)

    Banerjee, Pallavi; Sarwade, Deepak; Singh, V. S.

    2008-08-01

    Growing demand for potable water for various needs has lead to indiscriminate exploitation of groundwater resources, particularly, in the terrain where surface water resources are negligible. One such area is an island where groundwater is the only source of fresh water. Groundwater is the prime source of fresh water on most of the atolls in the world. Groundwater on these islands is in the form of thin fragile floating lens and is often vulnerable to overexploitation, draught, tidal waves, tsunami and cyclone resulting in seawater ingress. Sustainable development of this meager source of fresh groundwater for a longer time becomes a more difficult task on small atolls with a large population depending on this vital resource. To develop a sustainable management scheme and identify the vulnerable part of aquifer, characterization of the aquifer system on islands is imperative. Groundwater on an atoll is extremely vulnerable to seawater mixing through natural as well as human activities. One such natural process is the tides of the ocean. The response of sea tide to the water table on the island offers valuable data as well as cost-effective means to characterize an aquifer system. Such characterization is vital for the management of groundwater resources on an atoll. The obtained results have compared well with the parameters obtained through a conventional pumping test. Therefore, the use of tidal response to the water table, which can easily be recorded, provides a rapid and cost-effective means to characterization of the aquifer system on the island.

  4. 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)

  5. 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.

  6. 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)

  7. 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.

  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. Water budget and mathematical model of the Coconino Aquifer, southern Navajo County, Arizona

    USGS Publications Warehouse

    Mann, Larry J.

    1979-01-01

    The main source of water in the 3,400-square-mile area of southern Navajo County, Ariz., is the large volume in storage in the Coconino aquifer. Withdrawals from the aquifer increased from about 13,800 acre-feet in 1960 to 38,400 acre-feet in 1972. Aquifer tests indicate that hydraulic conductivity ranges from 8 to 40 feet per day; the flow-net analysis indicates that the hydraulic conductivity may be as much as 80 feet per day in places. In the southern and central parts the aquifer is unconfined, and the storage coefficient is estimated to be about 0.15. In the northern and eastern parts the aquifer is confined, and the storage coefficient ranges from 0.00013 to 0.0014. A mathematical model was developed to simulate the groundwater system and to provide a management tool for estimating the effects of pumping. The model indicates that the inflow to and outflow from the aquifer were about 105,600 acre-feet in 1960 and that about 192,000 acre-feet of water was derived from storage in 1960-72. The model provides an approximation of the Coconino aquifer. (USGS)

  10. Effect of faults on fluid flow and chloride contamination in a carbonate aquifer system

    USGS Publications Warehouse

    Maslia, M.L.; Prowell, D.C.

    1990-01-01

    A unified, multidiscipline hypothesis is proposed to explain the anomalous pattern by which chloride has been found in water of the Upper Floridan aquifer in Brunswick, Glynn County, Georgia. Analyses of geophysical, hydraulic, water chemistry, and aquifer test data using the equivalent porous medium (EPM) approach are used to support the hypothesis and to improve further the understanding of the fracture-flow system in this area. Using the data presented herein we show that: (1) four major northeast-southwest trending faults, capable of affecting the flow system of the Upper Floridan aquifer, can be inferred from structural analysis of geophysical data and from regional fault patterns; (2) the proposed faults account for the anomalous northeastward elongation of the potentiometric surface of the Upper Floridan aquifer; (3) the faults breach the nearly impermeable units that confine the Upper Floridan aquifer from below, allowing substantial quantities of water to leak vertically upward; as a result, aquifer transmissivity need not be excessively large (as previously reported) to sustain the heavy, long-term pumpage at Brunswick without developing a steep cone of depression in the potentiometric surface; (4) increased fracturing at the intersection of the faults enhances the development of conduits that allow the upward migration of high-chloride water in response to pumping from the Upper Floridan aquifer; and (5) the anomalous movement of the chloride plume is almost entirely controlled by the faults. ?? 1990.

  11. Framework for Evaluating Water Quality of the New England Crystalline Rock Aquifers

    USGS Publications Warehouse

    Harte, Philip T.; Robinson, Gilpin R., Jr.; 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.

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. Hydrostratigraphic modeling of a complex, glacial-drift aquifer system for importation into MODFLOW.

    PubMed

    Herzog, Beverly L; Larson, David R; Abert, Curtis C; Wilson, Steven D; Roadcap, George 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 2,200 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. PMID:12533076

  19. Analytical solutions for recession analyses of sloping aquifers in alpine catchments

    NASA Astrophysics Data System (ADS)

    Pauritsch, Marcus; Hergarten, Stefan; Winkler, Gerfried; Birk, Steffen

    2015-04-01

    Analytical solutions for the discharge recession of sloping aquifers are commonly used to simulate the runoff of shallow aquifers with slope angles of a few degrees and in particular hillslopes. However, in alpine catchments, potentially deeper aquifers represented by debris accumulations such as relict rock glaciers can be found in areas with much steeper slope angles. These aquifers might be important for flood reduction and drought prevention and the discharged water can be used for drinking water supply and small hydroelectric power plants. Here it is attempted to reproduce the recession behavior of such highly inclined aquifers by applying existing analytical solutions for sloping aquifers. More specifically, an analytical solution for the discharge recession of a sloping aquifer is compared to a numerical model (MODFLOW) for a variety of slope angles. In addition a sensitivity analysis is made to reveal the effects of the various approximations introduced in the analytical solution, such as homogeneity, parallel side boundaries and a straight profile. The results show that the deviation between the analytical solution and the numerical model depends on the hydraulic properties and is in general acceptable for all tested slope angles. However, the sensitivity analysis shows that the simplifying assumptions and especially the initial condition have great impact on the discharge recession. Therefore, only the long-term behavior of the analytical solution should be considered if the model is employed for aquifer characterization. In summary, the combined use of analytical solutions and simple numerical models helps to better understand the opportunities and limitations of the recession analysis of sloping aquifers.

  20. Bayesian joint inversion of surface deformation and hydraulic data for aquifer characterization

    NASA Astrophysics Data System (ADS)

    Hesse, M. A.; Stadler, G.

    2013-12-01

    Remote sensing and geodetic measurements are providing a wealth of new, spatially-distributed, time-series data that promise to improve the characterization of regional aquifers. The integration of these geodetic measurements with other hydrological observations has the potential to aid the sustainable management of groundwater resources through improved characterization of the spatial variation of aquifer properties. The joint inversion of geomechanical and hydrological data is challenging, because it requires fully-coupled hydrogeophysical inversion for the aquifer parameters, based on a coupled geomechanical and hydrological process model. We formulate a Bayesian inverse problem to infer the lateral permeability variation in an aquifer from geodetic and hydraulic data, and from prior information. We compute the maximum a posteriori (MAP) estimate of the posterior permeability distribution, and use a local Gaussian approximation around the MAP point to characterize the uncertainty. For two-dimensional test cases we also explore the full posterior permeability distribution through Markov-Chain Monte Carlo (MCMC) sampling. To cope with the large parameter space dimension, we use local Gaussian approximations as proposal densities in the MCMC algorithm. Using increasingly complex model problems, based on the work of Mandel (1953) and Segall (1985), we find the following general properties of poroelastic inversions: (1) Augmenting standard hydraulic well data by surface deformation data improves the aquifer characterization. (2) Surface deformation contributes the most in shallow aquifers, but provides useful information even for the characterization of aquifers down to 1 km. (3) In general, it is more difficult to infer high permeability regions, and their characterization requires frequent measurement to resolve the associated short response time scales. (4) In horizontal aquifers, the vertical component of the surface deformation provides a smoothed image of the

  1. Overview of the Ogallala Aquifer Program

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Irrigation increased markedly on the Southern High Plains during the second half of the 20th century, drawing water primarily from the Ogallala Aquifer. During this time, irrigation sustained regional farm incomes and rural economies. Withdrawals from the aquifer, however, have exceeded recharge, re...

  2. 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.

  3. 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

  4. VULNERABILITY OF KARST AQUIFERS TO CHEMICAL CONTAMINATION

    EPA Science Inventory

    Ground water flow in karst aquifers is very different from flow in granular or fractured aquifers. arst ground water flow is often turbulent within discrete conduits that are convergent in the upper reaches and divergent in the lower, simulating discharge to one or more springs. ...

  5. 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...

  6. ANALYTIC ELEMENT MODELING OF COASTAL AQUIFERS

    EPA Science Inventory

    Four topics were studied concerning the modeling of ground-water flow in coastal aquifers with analytic elements: (1) practical experience was obtained by constructing a ground-water model of the shallow aquifers below the Delmarva Peninsula USA using the commercial program MVAEM...

  7. 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.

  8. 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

  9. 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

  10. A leaky aquifer below Champlain Sea clay: closed-form solutions for natural seepage.

    PubMed

    Chapuis, Robert P; Saucier, Antoine

    2013-01-01

    Closed-form solutions are proposed for natural seepage in semiconfined (leaky) aquifers such as those existing below the massive Champlain Sea clay layers in the Saint-Lawrence River Valley. The solutions are for an ideal horizontal leaky aquifer below an ideal aquitard that may have either a constant thickness and a constant hydraulic head at its surface, or a variable thickness and a variable hydraulic head at its surface. A few simplifying assumptions were needed to obtain the closed-form solutions. These have been verified using a finite element method, which did not make any of the assumptions but gave an excellent agreement for hydraulic heads and groundwater velocities. For example, the difference between the two solutions was smaller than 1 mm for variations in the 5 to 8 m range for the hydraulic head in the semiconfined aquifer. Note that fitting the hydraulic head data of monitoring wells to the theoretical solutions gives only the ratio of the aquifer and aquitard hydraulic conductivities, a clear case of multiple solutions for an inverse problem. Consequently, field permeability tests in the aquitard and the aquifer, and pumping tests in the aquifer, are still needed to determine the hydraulic conductivity values. PMID:23441962

  11. 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.

  12. Coupled aquifer-borehole simulation.

    PubMed

    Clemo, Tom

    2010-01-01

    A model coupling fluid hydraulics in a borehole with fluid flow in an aquifer is developed in this paper. Conservation of momentum is used to create a one-dimensional steady-state model of vertical flow in an open borehole combined with radially symmetric flow in an aquifer and with inflow to the well through the wellbore screen. Both laminar and turbulent wellbore conditions are treated. The influence of inflow through the wellbore screen on vertical flow in the wellbore is included, using a relation developed by Siwoń (1987). The influence of inflow reduces the predicted vertical variation in head up to 15% compared to a calculation of head losses due to fluid acceleration and the conventional Colebrook-White formulation of friction losses in a circular pipe. The wellbore flow model is embedded into the MODFLOW-2000 ground water flow code. The nonlinear conservation of momentum equations are iteratively linearized to calculate the conductance terms for vertical flow in the wellbore. The resulting simulations agree favorably with previously published results when the model is adjusted to meet the assumptions of the previous coupled models. PMID:19682095

  13. 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.

  14. 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.

  15. 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

  16. 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

  17. Regeneration of a confined aquifer after redevelopment and decommission of artesian wells, example from Grafendorf aquifer (Styria, Austria)

    NASA Astrophysics Data System (ADS)

    Mehmedovski, Nudzejma; Winkler, Gerfried

    2016-04-01

    Water is essential for life and it is therefore necessary to protect drinking water sustainably. Compared to shallow groundwater, deeper groundwater is especially important due to its characteristic tendency to remain extensively unaffected by environmental impacts. Thus, the uncontrolled waste of this valuable resource has to be avoided. A lot of artesian wells have been established in Grafendorf bei Hartberg (Styria, Austria). Almost all wells were not state-of-the art. As a result the different aquifer horizons began to intermix. Additionally some of the artesian wells had a permanent free overflow and the water was not even used. Consequently, since 1950, where the mean discharge of 37 wells was 0,334 l/s per well, the discharge has decreased to 0,090 l/s until 2013, which means a decline of about 75 %. As a reaction to these declines a decommissioning campaign was conducted where 69 artesian wells have been closed by injecting a cement-bentonite suspension (ratio 3:1). The Grafendorf aquifer is situated in the Styrian Basin and consists of 5 separated artesian horizons in Neogene sediments. These artesian horizons range from 42 m (1st horizon) to 176 m (5th horizon) and mostly consist of sand, partly of fine/medium/coarse gravel and partially with minor clay content. In order to analyse the reaction of the Grafendorf aquifer to these redevelopments, 5 monitoring wells could be used for the analysis. Some monitoring wells include different aquifer horizons and hydraulically short cut them. Thus, in this work the analysis focus on the general trend of the whole aquifer system neglecting the individual interactions between the different aquifers. In a first investigation step the hydraulic properties of the aquifer system has been determined using pumping tests which were analysed with different analytical solutions with the software AQTESOLV. Overall the pumping test solutions hardly differ in the transmissivity and hydraulic conductivity. On the contrary the

  18. Availability of ground water from the alluvial aquifer on the Nisqually Indian Reservation, Washington

    USGS Publications Warehouse

    Lum, W. E., II

    1984-01-01

    A digital model using finite-difference techniques was constructed to simulate ground-water flow in an alluvial aquifer on the Nisqually Indian Reservation. The maximum long-term rate of pumping from individual wells, based on available data, is about 0.75 cubic feet per second (340 gallons per minute). Data on the extent, hydraulic conductivity, saturated thickness of the alluvial aquifer, and quality of the ground water was obtained primarily from the more than 22 test holes drilled for this project. The test holes ranged in depth from about 10 to 100 feet. The saturated thickness of the alluvium was found to range generally from about 10 to 60 feet in the area investigated. The water table is usually less than 10 feet below land surface. The hydraulic conductivity of the aquifer was determined to range from 8.5 to 170 feet per day. The leakage coefficient of the river bed material was determined to be about 0.06 foot per day. Rainfall recharge to the aquifer is about 10 inches per year. A U.S. Geological Survey two-dimensional digital computer model was calibrated to simulate ground-water flow in the alluvial aquifer (area investigated is about 1.1 square miles). The calibrated model simulated measured water levels in the alluvial aquifer to within about 1 foot at 13 of 17 test well locations throughout the model area and within 2 feet at 16 of 17 test well locations. When pumping from the alluvial aquifer was simulated with the computer model it was found that 90 to 100 percent of the water pumped from wells was derived from induced recharge from the Nisqually River into the aquifer and (or) reduced discharge from the aquifer to the Nisqually River. Wells drilled for a large demand use such as a fish hatchery supply will achieve the highest yield if they are placed close to the Nisqually River and in the areas of greatest saturated thickness and highest permeability of the aquifer. (USGS)

  19. Earth-Tide Derived Aquifer Properties in Fractured Granite: Results from a Groundwater Monitoring Well Network in the Peninsular Ranges Batholith

    NASA Astrophysics Data System (ADS)

    Weinberger, J. L.; Quinlan, P. T.; Tartakovsky, D. M.

    2014-12-01

    Fractured rock aquifers are difficult to characterize because of the three dimensional spatial heterogeneity of the fracture networks. Aquifer properties cannot be determined from a single borehole and traditional aquifer tests are difficult to design and analyze without prior knowledge of the subsurface permeability distribution. Using passive monitoring of the water level responses to tidal strains in wells allows for characterization of the aquifer over greater spatial extent and can be used to guide the design and implementation of aquifer tests. In this study, the water level response to tidal strains measured in over 20 groundwater wells, spaced irregularly over an approximately 48 km2 area, was used to estimate the specific storage and transmissivity of the surrounding granite aquifer. The water level data were corrected to remove barometric pressure effects before the amplitude and phase shifts for the O1 and M2 components of the tidal potential were calculated. Systematic differences in the calculated aquifer characteristics were observed. The differences correlate with the density of fractures observed in borehole geophysical logs. The aquifer properties derived from the earth-tide analysis were compared to those derived from aquifer tests conducted at two of the wells analyzed. The two methods yielded similar results.

  20. Protistan communities in aquifers: a review.

    PubMed

    Novarino, G; Warren, A; Butler, H; Lambourne, G; Boxshall, A; Bateman, J; Kinner, N E; Harvey, R W; Mosse, R A; Teltsch, B

    1997-07-01

    Eukaryotic microorganisms (protists) are a very important component of microbial communities inhabiting groundwater aquifers. This is not unexpected when one considers that many protists feed heterotrophically, by means of either phagotrophy (bacterivory) or osmotrophy. Protistan numbers are usually low (< 10(2) per g dw of aquifer material) in pristine, uncontaminated aquifers but may increase by several orders of magnitude in aquifers subject to organic pollution. Small flagellates (typically 2-3(5) microns in size in situ) are by far the dominant protists in aquifers, although amoebae and occasionally ciliates may also be present in much lower numbers. Although a wealth of new taxonomic information is waiting to be brought to light, interest in the identity of aquifer protists is not exclusively academic. If verified, the following hypotheses may prove to be important towards our understanding of the functioning of microbial communities in aquifers: (1) Differences in swimming behavior between species of flagellates lead to feeding heterogeneity and niche differentiation, implying that bacterivorous flagellates graze on different subsets of the bacterial community, and therefore play different roles in controlling bacterial densities. (2) Bacterivorous flagellates grazing on bacteria capable of degrading organic compounds have an indirect effect on the overall rates of biodegradation. PMID:9299706

  1. Probing Shallow Aquifers in Northern Kuwait Using Airborne Sounding Radars

    NASA Astrophysics Data System (ADS)

    Heggy, E.; Fadlelmawla, A.; Farr, T. G.; Al-Rashed, M.

    2011-12-01

    Most of the global warming observations, scientific interest and data analyses have concentrated on the earth Polar Regions and forested areas, as they provide direct measurable impacts of large scale environmental changes. Unfortunately, the arid environments, which represent ~20% of the earth surface, have remained poorly studied. Yet water rarity and freshness, drastic changes in rainfall, flash floods, high rates of aquifer discharge and an accelerated large-scale desertification process are all alarming signs that suggest a substantial large-scale climatic variation in those areas that can be correlated to the global change that is affecting the volatile dynamic in arid zones. Unfortunately the correlations, forcings and feedbacks between the relevant processes (precipitation, surface fresh water, aquifer discharge, sea water rise and desertification) in these zones remain poorly observed, modeled, let alone understood. Currently, local studies are often oriented toward understanding small-scale or regional water resources and neither benefit from nor feedback to the global monitoring of water vapor, precipitation and soil moisture in arid and semi-arid areas. Furthermore techniques to explore deep subsurface water on a large scale in desertic environments remain poorly developed making current understanding of earth paleo-environment, water assessment and exploration efforts poorly productive and out-phased with current and future needs to quantitatively understand the evolution of earth water balance. To address those deficiencies we performed a comprehensive test mapping of shallow subsurface hydro-geological structures in the western Arabic peninsula in Kuwait, using airborne low frequency sounding radars with the main objectives to characterize shallow fossil aquifers in term of depth, sizes and water freshness. In May 2011, an experimental airborne radar sounder operating at 50 MHz was deployed in Kuwait and demonstrated an ability to penetrate down to

  2. Vertical transport processes in unconfined aquifers

    NASA Astrophysics Data System (ADS)

    Ostendorf, David W.; Reckhow, David A.; Popielarczyk, David J.

    1989-02-01

    We derive simple two-dimensional mathematical models describing the unsteady transport of conservative contaminants through an unconfined aquifer with a gently sloping aquiclude subject to advection, recharge, and vertical dispersion. The inclusion of vertical transport terms permits the proper nonreactive analysis of closed and open chemical systems, with the latter allowing dispersion of volatile constituents across the water table. These systems exhibit conservative and pseudoreactive behavior respectively when the pollution is analyzed on a depth-integrated basis, as is common in present one-dimensional models of groundwater contamination. Vertical and longitudinal chloride and total inorganic carbon observations at the well-documented Babylon, Long Island sanitary landfill plume are used to calibrate and test the analyses with a modest level of accuracy, using the vertical dispersivity as a calibration factor in this testing process. The parameter is important in the determination of reaeration rates across the water table and nutrient mixing from below in the related problem of biological transformations near the free surface.

  3. Analysis of aquifer mineralization by paleodrainage channels

    USGS Publications Warehouse

    Rubin, H.; Buddemeier, R.W.

    2003-01-01

    Mineralization of groundwater resources is a problem in south-central Kansas, due to the penetration of saline water from Permian bedrock formations into the overlying alluvial aquifer. One of the mechanisms involved in the mineralization involves small bedrock features of high permeability located in places occupied by streams and rivers in past geological eras. These geological features are termed 'paleodrainage channels'. The permeability of the overlying aquifer can be significantly smaller than that of the channel fill material. The comparatively fast migration of saline water through these channels of high permeability is associated with the transfer of minerals into the overlying freshwater aquifer. This study applies a set of boundary layer approaches to quantify the process of mineral transfer from the channels into the aquifer. The methods used in the present study provide quick estimation and evaluation of the dilution of the channel flow, as well as mineral concentration profile changes in the mineralized zone created in the overlying aquifer. More generally, the method can also be useful for the analysis and evaluation of various types of groundwater contamination in heterogeneous aquifers. The application of the method is exemplified by a complete set of calculations characterizing the possible mineralization process at a specific channel in south central Kansas. Sensitivity analyses are performed and provide information about the importance of the various parameters that affect the mineralization process. Some possible scenarios for the aquifer mineralization phenomena are described and evaluated. It is shown that the channel mineralization may create either several stream tubes of the aquifer with high mineral concentration, or many stream tubes mineralized to a lesser extent. Characteristics of these two patterns of aquifer mineralization are quantified and discussed. ?? 2003 Published by Elsevier Science B.V.

  4. Groundwater modeling of Saq Aquifer Buraydah Al Qassim for better water management strategies.

    PubMed

    Al-Salamah, Ibrahim S; Ghazaw, Yousry M; Ghumman, Abdul Razzaq

    2011-02-01

    Saudi Arabia is an arid country. It has limited water supplies. About 80-90% of water supplies come from groundwater, which is depleting day by day. It needs appropriate management. This paper has investigated groundwater modeling of Saq Aquifer in Buraydah Al Qassim to estimate the impact of its excessive use on depletion of Saq Aquifer. MODFLOW model has been used in this study. Data regarding the aquifer parameters was measured by pumping tests. Groundwater levels and discharge of wells in the area for the year 2008 and previous record of year 1999 have been collected from Municipal Authority of Buraydah. Location of wells was determined by Garmin. The model has been run for different sets of pumping rates to recommend an optimal use of groundwater resources and get prolonged life of aquifer. Simulations have been made for a long future period of 27 years (2008-2035). Model results concluded that pumping from the Saq Aquifer in Buraydah area will result into significant cones of depression if the existing excessive pumping rates prevail. A drawdown up to 28 m was encountered for model run for 27 years for existing rates of pumping. Aquifer withdrawals and drawdowns will be optimal with the conservation alternative. The management scheme has been recommended to be adopted for the future protection of groundwater resources in Kingdom of Saudi Arabia. PMID:20364311

  5. Impacts of Soil-aquifer Heat and Water Fluxes on Simulated Global Climate

    NASA Technical Reports Server (NTRS)

    Krakauer, N.Y.; Puma, Michael J.; Cook, B. I.

    2013-01-01

    Climate models have traditionally only represented heat and water fluxes within relatively shallow soil layers, but there is increasing interest in the possible role of heat and water exchanges with the deeper subsurface. Here, we integrate an idealized 50m deep aquifer into the land surface module of the GISS ModelE general circulation model to test the influence of aquifer-soil moisture and heat exchanges on climate variables. We evaluate the impact on the modeled climate of aquifer-soil heat and water fluxes separately, as well as in combination. The addition of the aquifer to ModelE has limited impact on annual-mean climate, with little change in global mean land temperature, precipitation, or evaporation. The seasonal amplitude of deep soil temperature is strongly damped by the soil-aquifer heat flux. This not only improves the model representation of permafrost area but propagates to the surface, resulting in an increase in the seasonal amplitude of surface air temperature of >1K in the Arctic. The soil-aquifer water and heat fluxes both slightly decrease interannual variability in soil moisture and in landsurface temperature, and decrease the soil moisture memory of the land surface on seasonal to annual timescales. The results of this experiment suggest that deepening the modeled land surface, compared to modeling only a shallower soil column with a no-flux bottom boundary condition, has limited impact on mean climate but does affect seasonality and interannual persistence.

  6. Analysis of an unconfined aquifer subject to asynchronous dual-tide propagation

    USGS Publications Warehouse

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

    2008-01-01

    Most published solutions for aquifer responses to ocean tides focus on the one-sided attenuation of the signal as it propagates inland. However, island aquifers experience periodic forcing from the entire coast, which can lead to integrated effects of different tidal signals, especially on narrow high-permeability islands. In general, studies disregard a potential time lag as the tidal wave sweeps around the island. We present a one-dimensional analytical solution to the ground water flow equation subject to asynchronous and asymmetric oscillating head conditions on opposite boundaries and test it on data from an unconfined volcanic aquifer in Maui. The solution considers sediment-damping effects at the coastline. The response of Maui Aquifers indicate that water table elevations near the center of the aquifer are influenced by a combination of tides from opposite coasts. A better match between the observed ground water head and the theoretical response can be obtained with the proposed dual-tide solution than with single-sided solutions. Hydraulic diffusivity was estimated to be 2.3 ?? 107 m 2/d. This translates into a hydraulic conductivity of 500 m/d, assuming a specific yield of 0.04 and an aquifer thickness of 1.8 km. A numerical experiment confirmed the hydraulic diffusivity value and showed that the y-intercepts of the modal attenuation and phase differences estimated by regression can approximate damping factors caused by low-permeability units at the boundary.

  7. Heat storage in the Hettangian aquifer in Berlin - results from a column experiment

    NASA Astrophysics Data System (ADS)

    Milkus, Chri(Sch)augott

    2015-04-01

    Aquifer Thermal Energy Storage (ATES) is a sustainable alternative for storage and seasonal availability of thermal energy. However, its impact on the subsurface flow regime is not well known. In Berlin (Germany), the Jurassic (Hettangian) sandstone aquifer with highly mineralized groundwater (TDS 27 g/L) is currently used for heat storage. The aim of this study was to examine the hydrogeochemical changes that are caused by the induced temperature shift and its effects on the hydraulic permeability of the aquifer. Column experiments were conducted, in which stainless steel columns were filled with sediment from the aquifer and flushed with native groundwater for several weeks. The initial temperature of the experiment was 20°C, comparable to the in-situ conditions within the aquifer. After reaching equilibrium between sediment and water, the temperature was increased to simulate heating of the aquifer. During the experiment, physical and chemical parameters (pH, ORP, dissolved oxygen and dissolved carbon dioxide) were measured at the outflow of the column and the effluent water was sampled. Using a Scanning Electron Microscope, the deposition of precipitated minerals and biofilm on sediment grains was analyzed. Changes in hydraulic properties of the sediment were studied by the use of tracer tests with Uranin.

  8. Recharge from rectangular areas to finite aquifers

    NASA Astrophysics Data System (ADS)

    Rao, N. H.; Sarma, P. B. S.

    1981-10-01

    A generalized analytical solution is derived for the growth of groundwater mound in finite aquifers bounded by open water bodies, in response to recharge from rectangular areas. Finite Fourier transforms are used to solve the linearized differential equation of groundwater flow. Unlike earlier solutions, the method presented here does not require the use of tables for evaluation of complicated functions. The solution is evaluated by comparison with existing numerical and analytical results. In stream-aquifer systems similar to those described above, application of the proposed solution is more realistic than using solutions available for infinite aquifers.

  9. 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 ...

  10. Availability and quality of water from shallow aquifers in Duval County, Florida

    USGS Publications Warehouse

    Causey, Lawson V.; Phelps, G.G.

    1978-01-01

    The shallow-aquifer system in Duval County, Fla., overlies the Florida aquifer and is composed chiefly of sand, clay, sandy clay, and limestone. Thickness of the system ranges from about 300 to 600 feet. The upper 150 feet of deposits, consisting of the water-table and shallow-rock zones, are the most dependable and economical source of supplemental water supply. The principal shallow water-bearing zone is a limestone bed 40 to 100 feet below land surface. Aquifer tests conducted at 13 sites in Duval County show that yields from the shallow aquifer vary from place to place within the county owing chiefly to variations in lithology of the saturated rocks and sediments. The limestone of the shallow-rock zone will yield as much as 200 gallons per minute to wells; the maximum yield at most of the sites tested was between 30 and 100 gallons per minute. The water-table zone generally yields 10 gallons per minute or less but at one site, where a water-table well tapped a shell bed near land surface, the well yielded more than 40 gallons per minute. The quality of water in the shallow aquifer system in Duval County is generally acceptable for most domestic, commercial, and industrial uses. In some places, however, it has a high iron concentration and is hard. The iron concentration exceeds 0.3 milligrams per liter in water from the water-table or shallow-rock zones at 7 of the 13 aquifer test sites. The hardness of water from the aquifer ranges from about 60 to about 180 milligrams per liter. (Kosco-USGS)

  11. Attachment and Detachment Behaviour of Adenovirus and Surrogates in Fine Granular Limestone Aquifer Material

    NASA Astrophysics Data System (ADS)

    Stevenson, Margaret; Blaschke, Alfred Paul; Kirschner, Alexander; Farnleitner, Andreas; Sommer, Regina; Sidhu, Jatinder

    2015-04-01

    Comparison of transport of virus surrogates to the pathogenic virus is necessary to understand the differences between the virus and surrogate. Since experiments using pathogenic viruses cannot be done in the field, laboratory tests using flow through soil columns are used. Adenovirus, nanoparticles, PRD1 and MS2 bacteriophages were tested in fine granular limestone aquifer material taken from a borehole at a managed aquifer recharge site in Adelaide, Southern Australia. Results show that PRD1 is the most appropriate surrogate for adenovirus in an aquifer dominated by calcite material, although PRD1 did not mimic the detachment behaviour of adenovirus successfully under high pH conditions. It was also found that the charge of the colloid is not a dominant removal mechanism in this system. Implications from this study could influence how field tests using bacteriophages and nanoparticles are interpreted.

  12. Conceptualization and simulation of the Edwards Aquifer, San Antonio region, Texas

    USGS Publications Warehouse

    Lindgren, Richard J.; Dutton, A.R.; Hovorka, S.D.; Worthington, S.R.H.; Painter, Scott

    2004-01-01

    sources of water to the Edwards aquifer, and inflow through the northern and northwestern model boundaries contributes 6.5 percent. The largest discharges are springflow (73.7 percent) and ground-water withdrawals by wells (25.7 percent). The principal source of water to the Edwards aquifer for the Edwards aquifer model transient simulation was recharge, constituting about 60 percent of the sources of water (excluding change in storage) to the Edwards aquifer during 1956, a drought period, and about 97 percent of the sources (excluding change in storage) during 1975, a period of above-normal rainfall and recharge. The principal discharges from the Edwards aquifer for the transient simulation were springflow and withdrawals by wells. During 1956, representing drought conditions, the change in storage (net water released from storage) was much greater than recharge, accounting for 75.9 percent of the total flow compared to 14.5 percent for recharge. Conversely, during 1975, representing above-normal rainfall and recharge conditions, recharge constituted 79.9 percent of the total flow, compared to 7.1 percent for the change in storage (net water added to storage). A series of sensitivity tests was made to ascertain how the model results were affected by variations greater than and less than the calibrated values of input data. Simulated hydraulic heads in the Edwards aquifer model were most sensitive to recharge, withdrawals, hydraulic conductivity of the conduit segments, and specific yield and were comparatively insensitive to spring-orifice conductance, northern boundary inflow, and specific storage. Simulated springflow in the Edwards aquifer model was most sensitive to recharge, withdrawals, hydraulic conductivity of the conduit segments, specific yield, and increases in northern boundary inflow and was comparatively insensitive to spring-orifice conductance and specific storage.

  13. Development of an aquifer management model AQMAN3D

    USGS Publications Warehouse

    Puig, Juan Carlos; Rolon-Collazo, L. I.; Pagan-Trinidad, Ishmael

    1990-01-01

    A computer code that enables the use of the USGS Modular groundwater flow model for aquifermanagement modeling has been developed. Aquifermanagement techniques integrate groundwater flow modeling with linear quadratic optimization methods for the solution of various aquifer management problems. The model AQMAN3D, is a modified version of a previously developed two-dimensional AQMAN model. The idea of coupling the AQMAN model with the MODULAR model arose because actual groundwater flow systems behave in a three dimensional manner, therefore requiring treatment as such, and due to the widespread use of MODULAR. The use of the AQMAN3D model permits the implementation of the technique known as aquifer managementmodeling. A generalized approach to obtain an optimal solution to an aquifer management problem is proposed, and a sample test problem is presented to illustrate the use of the model. Even though the model provides the hydrologist with a new and powerful investigative tool, its applicability is limited to confined or quasiconfined systems.

  14. Can arsenic occurrence rates in bedrock aquifers be predicted?

    PubMed Central

    Yang, Qiang; Jung, Hun Bok; Marvinney, Robert G.; Culbertson, Charles W.; Zheng, Yan

    2012-01-01

    A high percentage (31%) of groundwater samples from bedrock aquifers in the greater Augusta area, Maine was found to contain greater than 10 µg L−1 of arsenic. Elevated arsenic concentrations are associated with bedrock geology, and more frequently observed in samples with high pH, low dissolved oxygen, and low nitrate. These associations were quantitatively compared by statistical analysis. Stepwise logistic regression models using bedrock geology and/or water chemistry parameters are developed and tested with external data sets to explore the feasibility of predicting groundwater arsenic occurrence rates (the percentages of arsenic concentrations higher than 10 µg L−1) in bedrock aquifers. Despite the under-prediction of high arsenic occurrence rates, models including groundwater geochemistry parameters predict arsenic occurrence rates better than those with bedrock geology only. Such simple models with very few parameters can be applied to obtain a preliminary arsenic risk assessment in bedrock aquifers at local to intermediate scales at other localities with similar geology. PMID:22260208

  15. Transport and variability of fecal bacteria in carbonate conglomerate aquifers.

    PubMed

    Goeppert, Nadine; Goldscheider, Nico

    2011-01-01

    Clastic sedimentary rocks are generally considered non-karstifiable and thus less vulnerable to pathogen contamination than karst aquifers. However, dissolution phenomena have been observed in clastic carbonate conglomerates of the Subalpine Molasse zone of the northern Alps and other regions of Europe, indicating karstification and high vulnerability, which is currently not considered for source protection zoning. Therefore, a research program was established at the Hochgrat site (Austria/Germany), as a demonstration that karst-like characteristics, flow behavior, and high vulnerability to microbial contamination are possible in this type of aquifer. The study included geomorphologic mapping, comparative multi-tracer tests with fluorescent dyes and bacteria-sized fluorescent microspheres, and analyses of fecal indicator bacteria (FIB) in spring waters during different seasons. Results demonstrate that (1) flow velocities in carbonate conglomerates are similar as in typical karst aquifers, often exceeding 100 m/h; (2) microbial contaminants are rapidly transported toward springs; and (3) the magnitude and seasonal pattern of FIB variability depends on the land use in the spring catchment and its altitude. Different groundwater protection strategies that currently applied are consequently required in regions formed by karstified carbonatic clastic rocks, taking into account their high degree of heterogeneity and vulnerability. PMID:20678141

  16. A stable and efficient numerical algorithm for unconfined aquifer analysis.

    PubMed

    Keating, Elizabeth; Zyvoloski, George

    2009-01-01

    The nonlinearity of equations governing flow in unconfined aquifers poses challenges for numerical models, particularly in field-scale applications. Existing methods are often unstable, do not converge, or require extremely fine grids and small time steps. Standard modeling procedures such as automated model calibration and Monte Carlo uncertainty analysis typically require thousands of model runs. Stable and efficient model performance is essential to these analyses. We propose a new method that offers improvements in stability and efficiency and is relatively tolerant of coarse grids. It applies a strategy similar to that in the MODFLOW code to the solution of Richard's equation with a grid-dependent pressure/saturation relationship. The method imposes a contrast between horizontal and vertical permeability in gridblocks containing the water table, does not require "dry" cells to convert to inactive cells, and allows recharge to flow through relatively dry cells to the water table. We establish the accuracy of the method by comparison to an analytical solution for radial flow to a well in an unconfined aquifer with delayed yield. Using a suite of test problems, we demonstrate the efficiencies gained in speed and accuracy over two-phase simulations, and improved stability when compared to MODFLOW. The advantages for applications to transient unconfined aquifer analysis are clearly demonstrated by our examples. We also demonstrate applicability to mixed vadose zone/saturated zone applications, including transport, and find that the method shows great promise for these types of problem as well. PMID:19341374

  17. Can arsenic occurrence rate in bedrock aquifers be predicted?

    USGS Publications Warehouse

    Yang, Qiang; Jung, Hun Bok; Marvinney, Robert G.; Culbertson, Charles W.; Zheng, Yan

    2012-01-01

    A high percentage (31%) of groundwater samples from bedrock aquifers in the greater Augusta area, Maine was found to contain greater than 10 μg L–1 of arsenic. Elevated arsenic concentrations are associated with bedrock geology, and more frequently observed in samples with high pH, low dissolved oxygen, and low nitrate. These associations were quantitatively compared by statistical analysis. Stepwise logistic regression models using bedrock geology and/or water chemistry parameters are developed and tested with external data sets to explore the feasibility of predicting groundwater arsenic occurrence rates (the percentages of arsenic concentrations higher than 10 μg L–1) in bedrock aquifers. Despite the under-prediction of high arsenic occurrence rates, models including groundwater geochemistry parameters predict arsenic occurrence rates better than those with bedrock geology only. Such simple models with very few parameters can be applied to obtain a preliminary arsenic risk assessment in bedrock aquifers at local to intermediate scales at other localities with similar geology.

  18. A stable and efficient numerical algorithm for unconfined aquifer analysis

    SciTech Connect

    Keating, Elizabeth; Zyvoloski, George

    2008-01-01

    The non-linearity of equations governing flow in unconfined aquifers poses challenges for numerical models, particularly in field-scale applications. Existing methods are often unstable, do not converge, or require extremely fine grids and small time steps. Standard modeling procedures such as automated model calibration and Monte Carlo uncertainty analysis typically require thousands of forward model runs. Stable and efficient model performance is essential to these analyses. We propose a new method that offers improvements in stability and efficiency, and is relatively tolerant of coarse grids. It applies a strategy similar to that in the MODFLOW code to solution of Richard's Equation with a grid-dependent pressure/saturation relationship. The method imposes a contrast between horizontal and vertical permeability in gridblocks containing the water table. We establish the accuracy of the method by comparison to an analytical solution for radial flow to a well in an unconfined aquifer with delayed yield. Using a suite of test problems, we demonstrate the efficiencies gained in speed and accuracy over two-phase simulations, and improved stability when compared to MODFLOW. The advantages for applications to transient unconfined aquifer analysis are clearly demonstrated by our examples. We also demonstrate applicability to mixed vadose zone/saturated zone applications, including transport, and find that the method shows great promise for these types of problem, as well.

  19. Aquifer descriptions from the U.S. Geological Survey Regional Aquifer-System Analysis Program, 1978-1993

    USGS Publications Warehouse

    Davidson, Claire B.; Doherty, Helen

    1994-01-01

    The Regional Aquifer-System Analysis Program of the U.S. Geological Survey began in 1978. The overall purpose of this program is to define the geologic, hydrologic, and geochemical framework of the Nation's most important aquifers and aquifer systems. This report summarizes the aquifer or aquifer system name, geographic area, rock units, equivalent names, lithology, thickness, hydrologic characteristics, water quality, water use, and references for 157 aquifers in 23 areas of the United States. A .zip file containing the aquifer data and data search programs (in compressed ASCII format) is included in the report.

  20. Digital data sets that describe aquifer characteristics of the Enid isolated terrace aquifer in northwestern Oklahoma

    USGS Publications Warehouse

    Becker, C.J.; Runkle, D.L.; Rea, Alan

    1997-01-01

    ARC/INFO export and nonproprietary format files The data sets in this report include digitized aquifer boundaries and maps of hydraulic conductivity, recharge, and ground-water level elevation contours for the Enid isolated terrace aquifer in northwestern Oklahoma. The Enid isolated terrace aquifer covers approximately 82 square miles and supplies water for irrigation, domestic, municipal, and industrial use for the City of Enid and western Garfield County. The Quaternary-age Enid isolated terrace aquifer is composed of terrace deposits that consist of discontinuous layers of clay, sandy clay, sand, and gravel. The aquifer is unconfined and is bounded by the underlying Permian-age Hennessey Group on the east and the Cedar Hills Sandstone Formation of the Permian-age El Reno Group on the west. The Cedar Hills Sandstone Formation fills a channel beneath the thickest section of the Enid isolated terrace aquifer in the midwestern part of the aquifer. All of the data sets were digitized and created from information and maps in a ground-water modeling thesis and report of the Enid isolated terrace aquifer. The maps digitized were published at a scale of 1:62,500. Ground-water flow models are numerical representations that simplify and aggregate natural systems. Models are not unique; different combinations of aquifer characteristics may produce similar results. Therefore, values of hydraulic conductivity and recharge used in the model and presented in this data set are not precise, but are within a reasonable range when compared to independently collected data.

  1. Innovative Field Methods for Characterizing the Hydraulic Properties of a Complex Fractured Rock Aquifer (Ploemeur, Brittany)

    NASA Astrophysics Data System (ADS)

    Bour, O.; Le Borgne, T.; Longuevergne, L.; Lavenant, N.; Jimenez-Martinez, J.; De Dreuzy, J. R.; Schuite, J.; Boudin, F.; Labasque, T.; Aquilina, L.

    2014-12-01

    Characterizing the hydraulic properties of heterogeneous and complex aquifers often requires field scale investigations at multiple space and time scales to better constrain hydraulic property estimates. Here, we present and discuss results from the site of Ploemeur (Brittany, France) where complementary hydrological and geophysical approaches have been combined to characterize the hydrogeological functioning of this highly fractured crystalline rock aquifer. In particular, we show how cross-borehole flowmeter tests, pumping tests and frequency domain analysis of groundwater levels allow quantifying the hydraulic properties of the aquifer at different scales. In complement, we used groundwater temperature as an excellent tracer for characterizing groundwater flow. At the site scale, measurements of ground surface deformation through long-base tiltmeters provide robust estimates of aquifer storage and allow identifying the active structures where groundwater pressure changes occur, including those acting during recharge process. Finally, a numerical model of the site that combines hydraulic data and groundwater ages confirms the geometry of this complex aquifer and the consistency of the different datasets. The Ploemeur site, which has been used for water supply at a rate of about 106 m3 per year since 1991, belongs to the French network of hydrogeological sites H+ and is currently used for monitoring groundwater changes and testing innovative field methods.

  2. Vulnerability of unconfined aquifers to virus contamination.

    PubMed

    Schijven, J F; Hassanizadeh, S Majid; de Roda Husman, Ana Maria

    2010-02-01

    An empirical formula was developed for determining the vulnerability of unconfined sandy aquifers to virus contamination, expressed as a dimensionless setback distance r(s)(*). The formula can be used to calculate the setback distance required for the protection of drinking water production wells against virus contamination. This empirical formula takes into account the intrinsic properties of the virus and the unconfined sandy aquifer. Virus removal is described by a rate coefficient that accounts for virus inactivation and attachment to sand grains. The formula also includes pumping rate, saturated thickness of the aquifer, depth of the screen of the pumping well, and anisotropy of the aquifer. This means that it accounts also for dilution effects as well as horizontal and vertical virus transport. Because the empirical model includes virus source concentration it can be used as an integral part of a quantitative viral risk assessment. PMID:20110099

  3. PRINCIPAL AQUIFERS, CURRENT POTENTIOMETRIC SURFACE MAPS, NC

    EPA Science Inventory

    Web page from North Carolina Department of Environment and Natural Resources (NC-DENR) to maps of potentiometric surfaces by aquifer in NC.
    http://www.dwr.ehnr.state.nc.us/hms/gwbranch/charact.htm

  4. Hydrology of the Tertiary-Cretaceous aquifer system in the vicinity of Fort Rucker Aviation Center, Alabama

    USGS Publications Warehouse

    Scott, J.C.; Law, L.R.; Cobb, Riley

    1984-01-01

    Fort Rucker Aviation Center, built in 1941-42, uses ground water for its water supply. The demand for water began to exceed the capacity of the well field in 1976. The Tertiary-Cretaceous aquifer system in the Fort Rucker area consists of an upper and lower aquifer. The upper aquifer consists of the basal part of the Tuscahoma Sand, the Nanafalia and Clayton Formations, and the upper part of the Providence Sand. The lower aquifer consists of the lower part of the Providence Sand and the Ripley Formation. Most large capacity (greater than 100 gal/min (gallons per minute)) wells in the Fort Rucker area are developed in one of these aquifers, and produce 500 gal/min or more. An aquifer test made at Fort Rucker during the study indicates that the transmissivity of the upper aquifer is about 7,000 ft sq/d (feet squared per day). This test and a potentiometric map of the area indicate that wells spaced too closely together is a major problem at pumping centers in the study area. (USGS)

  5. OXIDATION-REDUCTION CAPACITIES OF AQUIFER SOLIDS

    EPA Science Inventory

    Measurements of the oxidation (i.e., of aqueous Cr2+) and reduction (i.e., of aqueous Cr2O72- and H202) capacities of aquifer solids and groundwater have been made on samples from a sand-and-gravel aquifer. The gro...

  6. Modeling approaches and strategies for data-scarce aquifers: example of the Dar es Salaam aquifer in Tanzania

    NASA Astrophysics Data System (ADS)

    Van Camp, Marc; Mjemah, Ibrahimu Chikira; Al Farrah, Nawal; Walraevens, Kristine

    2013-03-01

    Management of groundwater resources can be improved by using groundwater models to perform risk analyses and to improve development strategies, but a lack of extensive basic data often limits the implementation of sophisticated models. Dar es Salaam in Tanzania is an example of a city where increasing groundwater use in a Pleistocene aquifer is causing groundwater-related problems such as saline intrusion along the coastline, lowering of water-table levels, and contamination of pumping wells. The lack of a water-level monitoring network introduces a problem for basic data collection and model calibration and validation. As a replacement, local water-supply wells were used for measuring groundwater depth, and well-top heights were estimated from a regional digital elevation model to recalculate water depths to hydraulic heads. These were used to draw a regional piezometric map. Hydraulic parameters were estimated from short-time pumping tests in the local wells, but variation in hydraulic conductivity was attributed to uncertainty in well characteristics (information often unavailable) and not to aquifer heterogeneity. A MODFLOW model was calibrated with a homogeneous hydraulic conductivity field and a sensitivity analysis between the conductivity and aquifer recharge showed that average annual recharge will likely be in the range 80-100 mm/year.

  7. Estimated Withdrawals from Stream-Valley Aquifers and Refined Estimated Withdrawals from Selected Aquifers in the United States, 2000

    USGS Publications Warehouse

    Sargent, B. Pierre; Maupin, Molly A.; Hinkle, Stephen R.

    2008-01-01

    The U.S. Geological Survey National Water Use Information Program compiles estimates of fresh ground-water withdrawals in the United States on a 5-year interval. In the year-2000 compilation, withdrawals were reported from principal aquifers and aquifer systems including two general aquifers - Alluvial and Other aquifers. Withdrawals from a widespread aquifer group - stream-valley aquifers - were not specifically identified in the year-2000 compilation, but they are important sources of ground water. Stream-valley aquifers are alluvial aquifers located in the valley of major streams and rivers. Stream-valley aquifers are long but narrow aquifers that are in direct hydraulic connection with associated streams and limited in extent compared to most principal aquifers. Based in large part on information published in U.S. Geological Survey reports, preliminary analysis of withdrawal data and hydrogeologic and surface-water information indicated areas in the United States where possible stream-valley aquifers were located. Further assessment focused on 24 states and the Commonwealth of Puerto Rico. Withdrawals reported from Alluvial aquifers in 16 states and withdrawals reported from Other aquifers in 6 states and the Commonwealth of Puerto Rico were investigated. Two additional States - Arkansas and New Jersey - were investigated because withdrawals reported from other principal aquifers in these two States may be from stream-valley aquifers. Withdrawals from stream-valley aquifers were identified in 20 States and were about 1,560 Mgal/d (million gallons per day), a rate comparable to withdrawals from the 10 most productive principal aquifers in the United States. Of the 1,560 Mgal/d of withdrawals attributed to stream-valley aquifers, 1,240 Mgal/d were disaggregated from Alluvial aquifers, 150 Mgal/d from glacial sand and gravel aquifers, 116 Mgal/d from Other aquifers, 28.1 Mgal/d from Pennsylvanian aquifers, and 24.9 Mgal/d from the Mississippi River Valley alluvial

  8. Geochemical detection of carbon dioxide in dilute aquifers

    PubMed Central

    2009-01-01

    Background Carbon storage in deep saline reservoirs has the potential to lower the amount of CO2 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 CO2 gas leak into dilute groundwater are important measures for the potential release of CO2 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 CO2 storage reservoir. Specifically, we address the relationships between CO2 flux, groundwater flow, detection time and distance. The CO2 flux ranges from 103 to 2 × 106 t/yr (0.63 to 1250 t/m2/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. Results For the scenarios we studied, our simulations show pH and carbonate chemistry are good indicators for leakage of stored CO2 into an overlying aquifer because elevated CO2 yields a more acid pH than the ambient groundwater. CO2 leakage into a dilute groundwater creates a slightly acid plume that can be detected at some distance from the leak source due to groundwater flow and CO2 buoyancy. pH breakthrough curves demonstrate that CO2 leaks can be easily detected for CO2 flux ≥ 104 t/yr within a 15-month time period at a monitoring well screened within a permeable layer 500 m downstream from the vertical gas trace. At lower flux rates, the CO2 dissolves in the aqueous phase in the lower most permeable

  9. Identification of the attenuation potential of a karst aquifer by an artificial dualtracer experiment with caffeine.

    PubMed

    Hillebrand, Olav; Nödler, Karsten; Licha, Tobias; Sauter, Martin; Geyer, Tobias

    2012-10-15

    Little is known with respect to the attenuation capacity of karst aquifers. Even less is known about the risk posed by emerging micropollutants in these systems. In order to identify the attenuation potential of karst aquifers in-situ and to estimate the risk posed by micropollutants, a dualtracer test was conducted in this study in order to investigate differential transport in the subsurface: The reactive compound caffeine was used as a tracer to indicate the attenuation capacity within the aquifer in-situ. Due to the low limit of quantification, only small amounts of caffeine needed to be injected. To calibrate a model and to visualize the attenuation of caffeine a conservative reference tracer (uranine) is injected simultaneously. The methodology is tested in a well-characterised karst system in southwest Germany. The results indicate a significantly higher attenuation rate than was expected for karst aquifers. The attenuation is decribed as a first-order process. The corresponding half-life is 104 h. This low half-life suggests that a generally assumed low natural attenuation capacity of karst aquifers is unjustified. The observed mass loss of caffeine illustrates the potential of caffeine to be used as reactive tracer for indicating in-situ attenuation capacity within highly hydraulically conductive systems, such as karst aquifers. Due to the high attenuation rate of caffeine it does not pose a threat as a long-time contaminant. In combination with a conservative reference tracer an economical and environmentally benign method is presented in this manuscript for the in-situ determination of the attenuation capacity of highly conductive aquifer systems. PMID:22877878

  10. Hydrogeology and ground-water flow of the drift and Platteville aquifer system, St Louis Park, Minnesota

    USGS Publications Warehouse

    Lindgren, R.J.

    1995-01-01

    Model simulations indicate that vertical ground-water flow from the drift aquifers and from the Platteville aquifer to underlying bedrock aquifers is greatest through bedrock valleys. The convergence of flow paths near bedrock valleys and the greater volume of water moving through the valleys would likely result in both increased concentrations and greater vertical movement of contaminants in areas underlain by bedrock valleys as compared to areas not underlain by bedrock valleys. Model results also indicate that field measurements of hydraulic head might not help locate discontinuities in confining units and additional test drilling to locate discontinuities might be necessary.

  11. Application of surface-geophysical methods to investigations of sand and gravel aquifers in the glaciated Northeastern United States

    USGS Publications Warehouse

    Haeni, F.P.

    1995-01-01

    Combined use of seismic-refraction, direct-current resistivity, very-low-frequency terrain-resistivity, and inductive terrain-conductivity methods were demonstrated at sites in Connecticut, New York, and Maine. Although no single method can define both the hydrogeologic boundaries and general grain-size characteristics of sand and gravel aquifers, a combination of these methods can. Comparisons of measured electrical properties of aquifers with logs of test holes and wells indicate that, for a given conductivity of ground water, the bulk electrical resistivity of aquifers in the glaciated Northeast increases with grain size.

  12. Digital data sets that describe aquifer characteristics of the Elk City Aquifer in western Oklahoma

    USGS Publications Warehouse

    Becker, C.J.; Runkle, D.L.; Rea, Alan

    1997-01-01

    ARC/INFO export and nonproprietary format files This diskette contains digitized aquifer boundaries and maps of hydraulic conductivity, recharge, and ground-water level elevation contours for the Elk City aquifer in western Oklahoma. The aquifer covers an area of approximately 193,000 acres and supplies ground water for irrigation, domestic, and industrial purposes in Beckham, Custer, Roger Mills, and Washita Counties along the divide between the Washita and Red River basins. The Elk City aquifer consists of the Elk City Sandstone and overlying terrace deposits, made up of clay, silt, sand and gravel, and dune sands in the eastern part and sand and gravel of the Ogallala Formation (or High Plains aquifer) in the western part of the aquifer. The Elk City aquifer is unconfined and composed of very friable sandstone, lightly cemented with clay, calcite, gypsum, or iron oxide. Most of the grains are fine-sized quartz but the grain size ranges from clay to cobble in the aquifer. The Doxey Shale underlies the Elk City aquifer and acts as a confining unit, restricting the downward movement of ground water. All of the data sets were digitized and created from information and maps in a ground-water modeling thesis and report of the Elk City aquifer. The maps digitized were published at a scale of 1:63,360. Ground-water flow models are numerical representations that simplify and aggregate natural systems. Models are not unique; different combinations of aquifer characteristics may produce similar results. Therefore, values of hydraulic conductivity and recharge used in the model and presented in this data set are not precise, but are within a reasonable range when compared to independently collected data.

  13. A General Solution for Groundwater Flow in Estuarine Leaky Aquifer System with Considering Aquifer Anisotropy

    NASA Astrophysics Data System (ADS)

    Chen, Po-Chia; Chuang, Mo-Hsiung; Tan, Yih-Chi

    2014-05-01

    In recent years the urban and industrial developments near the coastal area are rapid and therefore the associated population grows dramatically. More and more water demand for human activities, agriculture irrigation, and aquaculture relies on heavy pumping in coastal area. The decline of groundwater table may result in the problems of seawater intrusion and/or land subsidence. Since the 1950s, numerous studies focused on the effect of tidal fluctuation on the groundwater flow in the coastal area. Many studies concentrated on the developments of one-dimensional (1D) and two-dimensional (2D) analytical solutions describing the tide-induced head fluctuations. For example, Jacob (1950) derived an analytical solution of 1D groundwater flow in a confined aquifer with a boundary condition subject to sinusoidal oscillation. Jiao and Tang (1999) derived a 1D analytical solution of a leaky confined aquifer by considered a constant groundwater head in the overlying unconfined aquifer. Jeng et al. (2002) studied the tidal propagation in a coupled unconfined and confined costal aquifer system. Sun (1997) presented a 2D solution for groundwater response to tidal loading in an estuary. Tang and Jiao (2001) derived a 2D analytical solution in a leaky confined aquifer system near open tidal water. This study aims at developing a general analytical solution describing the head fluctuations in a 2D estuarine aquifer system consisted of an unconfined aquifer, a confined aquifer, and an aquitard between them. Both the confined and unconfined aquifers are considered to be anisotropic. The predicted head fluctuations from this solution will compare with the simulation results from the MODFLOW program. In addition, the solutions mentioned above will be shown to be special cases of the present solution. Some hypothetical cases regarding the head fluctuation in costal aquifers will be made to investigate the dynamic effects of water table fluctuation, hydrogeological conditions, and

  14. Aquifer characteristics, water availability, and water quality of the Quaternary aquifer, Osage County, northeastern Oklahoma, 2001-2002

    USGS Publications Warehouse

    Mashburn, Shana L.; Cope, Caleb C.; Abbott, Marvin M.

    2003-01-01

    Additional sources of water are needed on the Osage Reservation for future growth and development. The Quaternary aquifer along the Arkansas River in the Osage Reservation may represent a substantial water resource, but limited amounts of hydrogeologic data were available for the aquifer. The study area is about 116 square miles of the Quaternary aquifer in the Arkansas River valley and the nearby upland areas along the Osage Reservation. The study area included the Arkansas River reach downstream from Kaw Lake near Ponca City, Oklahoma to upstream from Keystone Lake near Cleveland, Oklahoma. Electrical conductivity logs were produced for 103 test holes. Water levels were determined for 49 test holes, and 105 water samples were collected for water-quality field analyses at 46 test holes. Water-quality data included field measurements of specific conductance, pH, water temperature, dissolved oxygen, and nitrate (nitrite plus nitrate as nitrogen). Sediment cores were extracted from 20 of the 103 test holes. The Quaternary aquifer consists of alluvial and terrace deposits of sand, silt, clay, and gravel. The measured thickness of the alluvium ranged from 13.7 to 49.8 feet. The measured thickness of the terrace sediments ranged from 7 to 93.8 feet. The saturated thickness of all sediments ranged from 0 to 38.2 feet with a median of 24.8 feet. The weighted-mean grain size for cores from the alluvium ranged from 3.69 to 0.64 f, (0.08- 0.64 millimeter), and ranged from 4.02 to 2.01 f (0.06-0.25 millimeter) for the cores from terrace deposits. The mean of the weighted-mean grain sizes for cores from the alluvium was 1.67 f (0.31 millimeter), and the terrace deposits was 2.73 f (0.15 millimeter). The hydraulic conductivity calculated from grain size of the alluvium ranged from 2.9 to 6,000 feet per day and of the terrace deposits ranged from 2.9 to 430 feet per day. The calculated transmissivity of the alluvium ranged from 2,000 to 26,000 feet squared per day with a median

  15. Geochemistry of the Madison and Minnelusa aquifers in the Black Hills area, South Dakota

    USGS Publications Warehouse

    Naus, Cheryl A.; Driscoll, Daniel G.; Carter, Janet M.

    2001-01-01

    Minnelusa aquifer. Three conceptual models, which are simplifications of lumped-parameter models, are considered for evaluation of mixing conditions and general ground-water ages. For a simple slug-flow model, which assumes no mixing, measured tritium concentrations in ground water can be related through a first-order decay equation to estimated concentrations at the time of recharge. Two simplified mixing models that assume equal proportions of annual recharge over a range of years also are considered. An ?immediate-arrival? model is used to conceptually represent conditions in outcrop areas and a ?time-delay? model is used for locations removed from outcrops, where delay times for earliest arrival of ground water generally would be expected. Because of limitations associated with estimating tritium input and gross simplifying assumptions of equal annual recharge and thorough mixing conditions, the conceptual models are used only for general evaluation of mixing conditions and approximation of age ranges. Headwater springs, which are located in or near outcrop areas, have the highest tritium concentrations, which is consistent with the immediate-arrival mixing model. Tritium concentrations for many wells are very low, or nondetectable, indicating general applicability of the timedelay conceptual model for locations beyond outcrop areas, where artesian conditions generally occur. Concentrations for artesian springs generally are higher than for wells, which indicates generally shorter delay times resulting from preferential flowpaths that typically are associated with artesian springs. In the Rapid City area, a distinct division of isotopic values for the Madison aquifer corresponds with distinguishing 18O signatures for nearby streams, where large streamflow recharge occurs. Previous dye testing in this area documented rapid ground-water flow (timeframe of weeks) from a streamflow loss zone to sites located several miles away. These results are used to ill

  16. Detailed performance and environmental monitoring of aquifer heating and cooling systems

    NASA Astrophysics Data System (ADS)

    Acuna, José; Ahlkrona, Malva; Zandin, Hanna; Singh, Ashutosh

    2016-04-01

    The project intends to quantify the performance and environmental impact of large scale aquifer thermal energy storage, as well as point at recommendations for operating and estimating the environmental footprint of future systems. Field measurements, test of innovative equipment as well as advanced modelling work and analysis will be performed. The following aspects are introduced and covered in the presentation: -Thermal, chemical and microbiological influence of akvifer thermal energy storage systems: measurement and evaluation of real conditions and the influence of one system in operation. -Follow up of energy extraction from aquifer as compared to projected values, recommendations for improvements. -Evaluation of the most used thermal modeling tool for design and calculation of groundwater temperatures, calculations with MODFLOW/MT3DMS -Test and evaluation of optical fiber cables as a way to measure temperatures in aquifer thermal energy storages

  17. Distributional Scaling in Heterogeneous Aquifers

    NASA Astrophysics Data System (ADS)

    Polsinelli, J. F.

    2015-12-01

    An investigation is undertaken into the fractal scaling properties of the piezometric head in a heterogeneous unconfined aquifer. The governing equations for the unconfined flow are derived from conservation of mass and the Darcy law. The Dupuit approximation will be used to model the dynamics. The spatially varying nature of the tendency to conduct flow (e.g. the hydraulic conductivity) is represented as a stochastic process. Experimental studies in the literature have indicated that the conductivity belongs to a class of non-stationary stochastic fields, called H-ss fields. The uncertainty in the soil parameters is imparted onto the flow variables; in groundwater investigations the potentiometric head will be a random function. The structure of the head field will be analyzed with an emphasis on the scaling properties. The scaling scheme for the modeling equations and the simulation procedure for the saturated hydraulic conductivity process will be explained, then the method will be validated through numerical experimentation using the USGS Modflow-2005 software. The results of the numerical simulations demonstrate that the head will exhibit multi-fractal scaling if the hydraulic conductivity exhibits multi-fractal scaling and the differential equations for the groundwater equation satisfy a particular set of scale invariance conditions.

  18. Natural attenuation processes of nitrate in a saline lake-aquifer system: Pétrola Basin (Central Spain)

    NASA Astrophysics Data System (ADS)

    Valiente, Nicolas; Menchen, Alfonso; Jirsa, Franz; Hein, Thomas; Wanek, Wolfgang; Gomez-Alday, Juan Jose

    2016-04-01

    Saline wetlands associated with intense agricultural activities in semi-arid to arid climates are among the most vulnerable environments to NO3‑ pollution. The endorheic Pétrola Basin (High Segura River Basin, Central Spain) was declared vulnerable to NO3‑ pollution by the Regional Government of Castilla-La Mancha in 1998. The hypersaline lake was classified as a heavily modified waterbody, due to the inputs of pollutants from agricultural sources and urban waste waters, the latest are discharged directly into the lake without proper treatment. Previous studies showed that the aquifer system has two main flow components: regional groundwater flow from recharge areas into the lake, and a density-driven flow from the lake to the underlying aquifer. The NO3‑ inputs derived from agriculture originate from nitrification of synthetic ammonium fertilizers, and afterwards, NO3‑ is expected to be attenuated by denitrification (up to 60%) in the saltwater-freshwater interface around the lake. However, the spatial and temporal pattern of nitrate reduction in lake sediments is not known. In this study, an isotope pairing technique was used in order to clarify the main pathways for the NO3‑ attenuation linked to the sediment-water interface. For that purpose mesocosm experiments were performed: organic-rich lake sediment (up to 23% organic carbon content) was incubated for 96 hours with the addition of 15N nitrate tracer. During the experiments two factors were modified: light and oxic conditions. Analyzing inorganic N-species (n=20) over time (72 hours) showed that NO3‑ attenuation was coupled with an increment in the NH4+ concentration (from 0.8 mg/L up to 5.3 mg/L) and a decrease in redox values (from 135.1 mV up to -422 mV) in the water column. The main outcome of this study was to elucidate the importance of different microbial pathways denitrification, dissimilatory nitrate reduction to ammonium (DNRA) and anaerobic ammonium oxidation (Anammox), in

  19. Pathogen and chemical transport in the karst limestone of the Biscayne aquifer: 1. Revised conceptualization of groundwater flow

    USGS Publications Warehouse

    Renken, R.A.; Cunningham, K.J.; Shapiro, A.M.; Harvey, R.W.; Zygnerski, M.R.; Metge, D.W.; Wacker, M.A.

    2008-01-01

    The Biscayne aquifer is a highly transmissive karst limestone that serves as the sole source of drinking water to over two million residents in south Florida. The aquifer is characterized by eogenetic karst, where the most transmissive void space can be an interconnected, touching-vug, biogenically influenced porosity of biogenic origin. Public supply wells in the aquifer are in close proximity to lakes established by surface mining. The mining of the limestone has occurred to the same depths as the production wells, which has raised concerns about pathogen and chemical transport from these surface water bodies. Hydraulic and forced gradient tracer tests were conducted to augment geologic and geophysical studies and to develop a hydrogeologic conceptual model of groundwater flow and chemical transport in the Biscayne aquifer. Geologic and geophysical data indicate multiple, areally extensive subhorizontal preferential flow zones of vuggy limestone separated by rock with a matrix pore system. The hydraulic response from an aquifer test suggests that the Biscayne aquifer behaves as a dual-porosity medium; however, the results of the tracer test showed rapid transport similar to other types of karst. The tracer test and concurrent temperature logging revealed that only one of the touching-vug flow zones dominates transport near the production wells. On the basis of the rising limb of the breakthrough curve, the dispersivity is estimated to be less than 3% of the tracer travel distance, which suggests that the fastest flow paths in the formation are likely to yield limited dilution of chemical constituents.

  20. Aquifer imaging with pressure waves—Evaluation of low-impact characterization through sandbox experiments

    NASA Astrophysics Data System (ADS)

    Zhou, YaoQuan; Lim, David; Cupola, Fausto; Cardiff, Michael

    2016-03-01

    Understanding the detailed spatial variation of hydraulic properties in the subsurface has been the subject of intensive research over the past three decades. A recently developed approach to characterize subsurface properties is hydraulic tomography, in which a series of pumping tests are jointly inverted using a heterogeneous numerical model. Recently, Cardiff et al. (2013) proposed a modified tomography approach named Oscillatory Hydraulic Tomography (OHT), in which periodic pumping signals of different frequencies serve as the aquifer stimulation, and pressure responses are recorded at observation locations for tomographic analysis. Its key advantages over traditional hydraulic tomography are that: (1) there is no net injection or extraction of water, and (2) the impulse (an oscillatory signal of known frequency) is easily extracted from noisy data. However, OHT has only been evaluated through numerical experiments to date. In this work, we evaluate OHT performance by attempting to image known heterogeneities in a synthetic aquifer. An instrumented laboratory sandbox is filled with material of known hydraulic properties, and we measure aquifer responses due to oscillatory pumping stimulations at periods of 2, 5, 10, and 20 s. Pressure oscillation time series are processed through Fourier Transforms and inverted tomographically to obtain estimates of aquifer heterogeneity, using a fast, steady-periodic groundwater flow model. We show that OHT is able to provide robust estimates of aquifer hydraulic conductivity even in cases where relatively few pumping tests and observation locations are available. The use of multiple stimulation frequencies is also shown to improve imaging results.

  1. Groundwater processes, sandplain seeps and interactions with regional aquifer systems in South-Western Australia

    NASA Astrophysics Data System (ADS)

    George, Richard J.

    1992-06-01

    Groundwater systems were studied in the 4200 ha East Belka catchment in a dryland farming area 300 km east of Perth, W.A., to determine the cause of sandplain seeps. Detailed investigations were carried out on a 200 ha hillslope to determine the characteristics of a shallow aquifer system responsible for the salinization of previously productive agricultural soils. The impact of the shallow aquifer on the regional system was investigated. A shallow (less than 8 m), perched, perennial aquifer was encountered in the deep sandplain materials. Groundwater discharge of about 1000 kl year -1 from the perched aquifer maintained saline soils across a 5 ha sandplain seep. Perching is due to the decreased permeability, geometry and silicification of the top of the mottled and pallid zones, and the convergence of perched ground waters near the seep. Slug test measurements suggest that the sandplain soils have a relatively low hydraulic conductivity (0.15 m day -1). Water qualities in the perched aquifer ranged from brackish to saline (3000-8000 mg l -1 TDS), peaking in the salt-affected area (12 000 mg l -1 TDS). High nitrate and Cl/Br ratios occur in the shallow aquifer and in the regional ground water beneath the sandplain seep. Recharge to the deep aquifer takes place throughout the catchment, but is greatest beneath the sandplain seep, where a perennial groundwater mound occurs. Recharge to the regional aquifer was estimated to be 6 to 15 mm year -1, increasing to between 20 and 60 mm year -1 beneath the seep. By contrast, less than 0.3 mm year -1 is able to leave the catchment as regional groundwater flow. Water-levels in the deep bores are consequently rising by 0.05 to 0.25 m year -1. Recharge to the deep aquifer beneath the seep, and low groundwater gradients, create the potential for groundwater flow to take place beneath the topographic divide and towards the adjoining catchment. However, as the vertical flux to the aquifer is two orders of magnitude greater than

  2. Aquifer Storage Recovery (ASR) of chlorinated municipal drinking water in a confined aquifer

    USGS Publications Warehouse

    Izbicki, John A.; Petersen, Christen E.; Glotzbach, Kenneth J.; Metzger, Loren F.; Christensen, Allen H.; Smith, Gregory A.; O'Leary, David R.; Fram, Miranda S.; Joseph, Trevor; Shannon, Heather

    2010-01-01

    About 1.02 x 106 m3 of chlorinated municipal drinking water was injected into a confined aquifer, 94-137 m below Roseville, California, between December 2005 and April 2006. The water was stored in the aquifer for 438 days, and 2.64 x 106 m3 of water were extracted between July 2007 and February 2008. On the basis of Cl data, 35% of the injected water was recovered and 65% of the injected water and associated disinfection by-products (DBPs) remained in the aquifer at the end of extraction. About 46.3 kg of total trihalomethanes (TTHM) entered the aquifer with the injected water and 37.6 kg of TTHM were extracted. As much as 44 kg of TTHMs remained in the aquifer at the end of extraction because of incomplete recovery of injected water and formation of THMs within the aquifer by reactions with freechlorine in the injected water. Well-bore velocity log data collected from the Aquifer Storage Recovery (ASR) well show as much as 60% of the injected water entered the aquifer through a 9 m thick, high-permeability layer within the confined aquifer near the top of the screened interval. Model simulations of ground-water flow near the ASR well indicate that (1) aquifer heterogeneity allowed injected water to move rapidly through the aquifer to nearby monitoring wells, (2) aquifer heterogeneity caused injected water to move further than expected assuming uniform aquifer properties, and (3) physical clogging of high-permeability layers is the probable cause for the observed change in the distribution of borehole flow. Aquifer heterogeneity also enhanced mixing of native anoxic ground water with oxic injected water, promoting removal of THMs primarily through sorption. A 3 to 4-fold reduction in TTHM concentrations was observed in the furthest monitoring well 427 m downgradient from the ASR well, and similar magnitude reductions were observed in depth-dependent water samples collected from the upper part of the screened interval in the ASR well near the end of the extraction

  3. Preliminary delineation and description of the regional