Confining Layer Study

Confining Layer Characteristics Cooperative Study -Final Report (April 2003)

COOPERATIVE STUDY PROPOSAL
Approved by the Inyo/Los Angeles Standing Committee March 23, 2000

Project Title:
Characterization of Confining Layer Hydraulic Conductivity and Storage Properties in Owens Valley, Inyo County, California.

Principal Investigators:
Inyo County Water Department — Randy Jackson.
LADWP — Saeed Jorat, (213) 367-1121,.

Purpose of the Study:
The purpose of the study is to provide vertical hydraulic conductivity and storage coefficient values for the confining unit (Hollett’s Hydrogeologic Unit 2, Hollett, 1991) based on field or laboratory derived data. The effect of pumping confined aquifers (Hollett’s Hydrogeologic Unit 3, Hollett, 1991) in the Owens Valley locally propagates to the shallow unconfined aquifer (Hollett’s Hydrogeologic Unit 1, Hollett, 1991) through low-conductivity confining materials . The vertical hydraulic conductivity and storage properties of these confining materials determine the rate and magnitude of propagation of deep confined aquifer drawdown to the shallow unconfined aquifer. Groundwater dependent vegetation relies on this shallow aquifer. Actual field derived values of the hydrologic properties of the confining unit are needed to provide a more realistic and rational basis for management of pumping from deep wells sealed to the confining layer. Furthermore, it would provide groundwater modeling projects with data for confining layer properties and indicate those areas where wells sealed to the confining layer would be most effective.

Background:
Extensive studies have been conducted on topics related to pumping below the confining units in Owens Valley. Most of these studies have concentrated on the effectiveness of sealing wells to the confining layer and pumping in the lower confined aquifer. Confining layer property characterization has been limited to a very few sites using pump tests and finite difference model calibration. In both these methods of characterization of confining layer properties, storage coefficients for the confining materials were estimated. Direct measurements of confining layer properties are lacking.

Qualitative evaluations of confining layer effectiveness in isolating drawdown effects to the deep aquifer for the Owens Valley were discussed by Kruse (1983) and Blevins (1984 ). The feasibility of sealing the shallow unconfined aquifer to the confining layer in production wells of the LADWP (Los Angeles Department of Water and Power) in Owens Valley was one of the Inyo/L.A. Enhancement/Mitigation (E/M) study projects conducted in 1986 (City of Los Angeles and Inyo County, April 1987). Recommendations from that project included a program of replacing production wells that are perforated in shallow zones. A maximum of 50 wells were recommended for replacement. In addition, the report recommended that all non-production/observation wells with shallow and deep perforations be converted to properly designed multi-zone observation wells, or sealed with grout to prevent cross-flow within the casing. The program of replacement was to begin in fiscal year 1987-88 by replacing six wells and replacing six more wells in fiscal year 1988-89. A schedule for replacing the remaining wells was to be developed as part of a long-term joint management plan but was not completed. The original replacement program of twelve wells was completed in 1991. Abandonments or conversion to monitoring wells of the replaced wells was completed in 1998. A schedule and rational for replacing the remaining wells has never been developed.

A deep test hole study was approved by the Standing Committee on April 15, 1987. Six deep test holes were drilled to depths ranging from 535 to 855 feet in the Taboose-Aberdeen area. The objective of that study was to determine if alternate well sites could be located and developed with minimal or no surface impact of pumping because of depth and separation of aquifers by confining layers (Coufal et al., 1991). That study found a large potentially high water producing alluvial aquifer beneath the upper basalt formation that varies in thickness from 250 to 500 feet within the study area. An apparently large and potentially high water producing volcanic aquifer exists below elevation 3300 in the study area. The thickness of the volcanic formation is unknown but it exceeds 430 feet in at least one location. This water bearing basalt is separated from the overlying shallow unconfined aquifer by the alluvial aquifer and the upper basalt formation. Thin but apparently continuous clay lenses in the alluvial aquifer will probably provide separation of deep pumping effects on the shallow unconfined aquifer if a well is perforated below the lenses. The degree of separation (confinement) is unknown. Because drilling costs were estimated to very high, between $350 and $450 per foot (1988 costs), two options were put forward for consideration by the two cooperative study participants. They were: 1) Drill and complete a production well in the lower basalt layer near the DT2 site. Total depth of the well is estimated to be approximately 1000 feet and; 2) Drill and complete a production well in the deeper alluvial aquifer (above 700 foot depth) near the DT2 site. In both options, deep and shallow aquifer response would have to be monitored during pumping to evaluate potential impacts.

In a preliminary evaluation of the hydrogeologic system in Owen Valley by the U.S. Geological Survey, Danskin (1988) found that vertical hydraulic conductivity of the confining unit probably plays a large role in determining groundwater flow patterns and rates. At that time, no values of vertical hydraulic conductivity were available for any part of Owens Valley. Danskin recommended that acquisition of a few values in key areas of the Owens Valley would significantly improve the understanding of the groundwater system. Danskin reviewed three methods typically used to determine vertical hydraulic conductivity. The methods are: 1) laboratory measurements of core samples, 2) aquifer tests with both a pumping well and multiple observation wells and 3) calibration of a groundwater flow model.

A second document by the U.S. Geological Survey, Water Resources Paper 2370-B, reviews then known or estimated characteristics of Hydrogeologic Unit 2 (Hollett et al, 1991). Three methods were used to derive these characteristics. The methods were 1) A leaky aquifer testing and analysis technique (Hantush, 1960), 2) a leaky aquifer testing and analysis technique described as the ratio method (Neuman and Witherspoon, 1971) and 3) calibration of a groundwater flow model. Vertical hydraulic conductivity of Hydrogeologic Unit 2 was estimated to range from 0.002 ft/d for poorly sorted deposits of clay with gravel to 0.00083 ft/d in the massive blue-green clay beds. Hollett (1991) did not identify which values of vertical hydraulic conductivity were derived by any of the above mentioned methods. Field data were not sufficient to estimate specific storage and so values derived by Neuman and Witherspoon (Neuman and Witherspoon, 1971) for similar sediments were used and tested using groundwater flow models. The specific storage of clay used in this study is about 0.00024.

Aquifer tests provide a means for defining the vertical hydraulic conductivity and under certain conditions the storage coefficient of confining materials. Wells sealed to the confining layer may provide aquifer test data that can be used in defining hydraulic properties of the confining layer. LADWP and Inyo County have performed aquifer tests and analyses on various wells sealed to the deeper confined aquifer in the Owens Valley. Among these wells are twelve replacement wells, 17 E/M wells, and recently, three replacement wells on the Bishop Cone. In addition, GPUAPCD and several consulting firms (Great Basin Unified Air Pollution Control District) have conducted aquifer tests on selected wells in the Owens Dry Lake area. Table 1, below summarizes the currently known aquifer testing in wells that may have been sealed to a confining layer and the known analyses. Analyses of 374 and E/M 375 were conducted by both LADWP and Inyo County. Inyo County analyses of 374 and E/M 375 included a value for confining layer vertical hydraulic conductivity of 0.01384 ft/d (Hutchison,1986). The value developed by Hutchison conflicts with that given by the U.S. Geological Survey for the blue green clays in this area (0.00083 ft/d). Hutchison’s value appears to be several orders of magnitude high relative to the U.S. Geological Survey estimate of vertical hydraulic conductivity. Confining layer vertical hydraulic conductivity estimates were developed for the Cabin Bar Area (LADWP and BLM, 1990) using the analysis developed by Hantush (1956). These values ranged from 0.018 ft/d to 0.034 ft/d. These values represent transition zone confinement; or rather lack of confinement in the transition zone. An aquifer test conducted at the Cottonwood well was analyzed using the Hantush model, and leakance values were reported (expressed as r/B values ) of 0.04 and 0.045 (LSCE, 1993). Only the aquifer tests at Big Pine and the Cabin Bar area produced confining layer vertical hydraulic conductivity values.

Table 1. Summary of Wells that may be Sealed to the Confining Layer with Aquifer Tests and Analyses.
(Please note that additional wells may be sealed to the confining layer, additional research may be necessary to locate these aquifer test data and analyses.)

Well No. Well Field Analyses Reference
391 IO Theis, Hantush LADWP, 1989
392 SS Theis, Hantush LADWP, 1989
393 SS Theis, Hantush LADWP, 1989
394 SS ? LADWP (?)
395 SS Theis, Hantush LADWP 1992
396 SS ? LADWP (?)
398 Laws Theis, Hantush LADWP(?),Jackson, 1991
399 Laws Lai and Su LADWP(?),Jackson, 1991
400 I0 Theis, Hantush LADWP(?),Jackson, 1991
401 IO Theis, Hantush LADWP(?),Jackson, 1991
402 SS Theis, Hantush, Neuman LADWP(?),Jackson, 1991
403 BG Theis, Hantush, Neuman LADWP(?),Jackson, 1991
374 BP Theis, Hantush LADWP, Hutchison, 1986
E/M 375 BP Theis, Hantush LADWP, 1986, Hutchison, 1986
E/M 376 Laws Theis, Hantush LADWP (?), Hutchison, 1986
E/M 377 Laws Theis, Hantush LADWP(?), Hutchison, 1986
E/M 378 BP ? ?
E/M 379 BP Theis, Hantush LADWP(?), Hutchison, 1986
E/M 380 TS Theis, Hantush LADWP,1992, Hutchison, 1986
E/M 381 TS Theis, Hantush LADWP,1992, Hutchison, 1986
E/M 382 TS Theis LADWP 1993
E/M 383 IO Theis, Hantush LADWP(?), Hutchison, 1986
E/M 384 IO Theis, Hantush LADWP(?), Hutchison, 1986
E/M 385 Laws Theis, Hantush LADWP(?), Hutchison, 1987
E/M 386 Laws Theis, Hantush LADWP(?), Hutchison, 1987
E/M 387 Laws Theis, Hantush LADWP(?), Hutchison, 1987
E/M 388 Laws Theis, Hantush LADWP(?), Hutchison, 1987
E/M 389 BP Theis, Hantush LADWP(?), Hutchison, 1987
E/M 390 LP Theis, Hantush LADWP(?), Hutchison, 1987
406 Bishop ? ?
407 Bishop ? ?
408 Bishop ? ?
USGS Wells ? ? ?
Keeler, Dunn and other Community Service District and Private Domestic Wells. ? ? ?
Selected Wells on or around Owens Lake Owens Lake Theis DRI (Jacobsen, et al, Various Dates).
Cottonwood Well Owens Lake Theis, Neuman, Hantush, 1956 CH2M Hill, 1991,Luhdorff and Scalmanini (LSCE), 1993
Cabin Bar Ranch Owens Lake Neuman, Hantush, 1956 LADWP, BLM 1990
Western Water Owens Lake ? ?

 

Empirical operational testing has been conducted on four sealed Enhancement/ Mitigation wells (E/M 380, E/M 381, E/M 375 and E/M 382) and an aqueduct supply well (396) by the Inyo County and the LADWP Technical Group. Pumping was conducted at well 396 in the Symmes-Shepherd wellfield in late 1992 and early 1993. Review of the test in a memorandum to the Inyo-LA Technical Group (Jackson, 1993) showed that the seal was not entirely effective at this location in isolating the drawdown effects to the deep aquifer. An evaluation of the linkage of E/M wells 380 and 381 to the TS4 monitoring site was conducted in 1997 and 1998 with pumping lasting up to a year. Review of the test data in January of 1997 (Jackson, 1997) showed no linkage to the shallow monitoring well at the TS4 monitoring site and no effect on the shallow water table. Review of data collected in 1998 show the same results. Seals placed in these wells are effective in isolating drawdown to the deep aquifer over the time period tested (i.e. specific to the pumping and runoff regime experienced during the test). Evaluation of the linkage of E/M 375 in Big Pine and E/M 382 in Thibaut-Sawmill was conducted in 1997 and 1998 (Harrington, 1998). No linkage to their respective monitoring sites was found. Isolation of drawdown effects to the deep aquifer was found in the case of E/M 375. The evaluation of the effects of pumping E/M 382 on the shallow water table was complicated by a nearby flowing well. The flowing well stopped flowing whenever E/M 382 was pumped and shallow water tables dropped as a result of the lack of recharge to the shallow aquifer from the flowing well (Inyo County and LADWP unpublished data, 1998). Recovery testing by first capping the flowing well for a month and then removing the cap, showed no recovery of shallow water levels after E/M 382 was turned off when the flowing well was capped and recovery in shallow water levels when the cap was removed. The test at E/M 382 should be reconducted by first shutting in all flowing wells for an appropriate period (until shallow water levels stabilize), and then pumping E/M 382 and observing the nearest shallow test hole (676T).

These operational tests at E/M and other wells were designed to investigate effects on the shallow water table. They were not designed to investigate the properties of the confining materials. The test data however, could be used in appropriate aquifer test analyses to define hydrologic characteristics of the confining layer.

Four regional groundwater flow modeling projects have recently been conducted by various entities in the Owens Valley. Table1, below, summarizes the projects, and describes the confining layer simulation and locates in original documentation the values used. The preliminary USGS Valley-Wide Model and the Owens Dry Lake area models by DRI were found to be particularly sensitive to confining layer hydrologic properties. Recently, the use of the work of Denis and Motz (1998) has suggested that confining layer vertical hydraulic conductivity may have been greatly overestimated in both versions of the Owens Dry Lake area models (Mike Smith, CDM, Personnel Communication, March 1999). This conclusion is based on the application of this analytical model to the upper aquifer test data at the Owens River site wells of GBUAPCD. The conclusion is not surprising, since the values used for vertical hydraulic conductivity of the confining unit (0.0283 ft/d) are derived from slug testing (bailer withdrawal for water chemistry sampling in shallow piezometers, followed by recovery) designed to determine horizontal hydraulic conductivity that was conducted in near surface relatively unconsolidated lake sediments (Tyler et al., 1996). There is no attempt to correct the horizontal hydraulic conductivity derived by application of typical values of anisotropy present in lakebed sediments. A medium to high degree of stratification would reduce the horizontal hydraulic conductivity by one-tenth to one-hundredth, respectively (Walton, 1988). This would reduce the vertical hydraulic conductivity from 0.0283 ft/d to a range of 0.00283 ft/d as a maximum and 0.000283 ft/d as a minimum. Vertical hydraulic conductivity of confining materials is very likely one or two orders of magnitude smaller than that modeled in the Owens Dry Lake area model.

Table 2. Confining Layer Simulation Summary of Recent Regional Groundwater Modeling Efforts in the Owens Valley.

Modeling Done by Area Code Year Confining Layer Simulation
Inyo County (Half Valley Model) BISHOP GW BASIN MODFLOW 1988 VCONT ARRAY Page 10a (Hutchison 1988) quasi-3d, Steady state and transient simulation.
LADWP (Half Valley Model) OWENS LAKE GW BASIN MODFLOW 1988 VCONT ARRAYPage 6 (LADWP, 1988) quasi-3d, steady state and transient simulation.
DRI (for GBUAPCD) OWENS LAKE AND VICINITY MODFLOW 1997 Hydraulic Conductivity and storage coefficient. Page 55 and111 (Wirganowicz, 1997) fully 3-d, Steady State and Transient Simulation
DRI (for GBUAPCD) OWENS LAKE AND VICINITY MODFLOW 1997 Hydraulic Conductivity and Anisotropy Ratio, Page 65 (Schumer, 1997) fully 3-d, Steady State simulation only
USGS ENTIRE OWENS VALLEY MODFLOW 1997 Plate 2, Leakance Values for zones, (Danskin, in Press)Quasi-3d

Confining layer properties are defined in a very few sites in these models and for the most part were estimated in calibration. The Bishop Basin Model, prepared by Inyo County, placed all the pumping in the deeper confined aquifer. Because of this assignment of pumping, values for confining layer properties may have been incorrectly estimated in order to calibrate the model for shallow unconfined wells.

Procedure:
The procedure proposed to develop and improve confining layer characterization will consist of four sequential tasks grouped into two phases. Phase I will consist of tasks 1 and 2. Phase II will consist of tasks 3 and 4. Funding for Phase I is sought at this time. Phase II funding is deferred to a later date, subject to approval of the Standing Committee. The first task will use the analytical model of Denis and Motz (Denis and Motz, 1998) to investigate the sensitivity of drawdowns in the shallow aquifer generated by pumping in deeper confined aquifers to the pumping rate in the confined aquifer and the thickness, vertical hydraulic conductivity and storage characteristics of the confining layer. The second task will be to analyze existing aquifer test and operational testing data with an emphasis on confining layer properties instead of production aquifer transmissivity and storativity. The third task will estimate vertical flow rates through the confining layer using measured temperature profiles from Owens Valley wells. The third task would only be initiated if the second task does not characterize the confining layer properties sufficiently. The forth task will include drilling and additional aquifer tests and recovery of cores at suitable locations with suitable monitoring wells designed specifically to measure confining layer parameters. The forth task would only be initiated if the other tasks do not provide adequate characterization of the confining layer.

Methods to be used:

PHASE I

Task 1: Sensitivity Analysis of the Coupled Aquifer Model of Denis and Motz.

An analytical solution has recently been derived in which transient and steady-state drawdown due to pumping can be calculated in one or both of two aquifers separated by a semipermeable confining unit in a confined aquifer system (Denis and Motz, 1998). The solution is different from existing analytical solutions in that it includes both confining unit storage and a drawdown-dependent ET (evapotranspiration) reduction term. The Denis and Motz solution has been compared with an equivalent MODFLOW (McDonald and Harbaugh, 1988) application utilizing the module TLK1 (Leake et al. 1994). The TLK1 module considers storage and vertical flow in confining units between aquifer units. The analytic solution and the finite difference solution matched well.

The sensitivity of drawdown in the unconfined aquifer to the characteristics of the confining layer and the pumping in the confined aquifer should be examined. A computer program has been acquired from Louis Motz, which calculates this analytical solution. Preliminary data exist for the E/M 375. Using these data as a basis, a sensitivity analysis will be performed for confining layer thickness, confining layer hydraulic conductivity, confining layer storage, and pumping rate in the confined aquifer. In addition various scenarios of leakage through the seal to the unconfined aquifer will be examined. The sensitivity analysis will be performed by Inyo County and reviewed by LADWP.

An attempt will be made to calibrate the analytical solution of Denis and Motz to long term operational tests conducted and E/M 380, 381, 375 and 382.

Task 2: Analyses of Available Aquifer Test Data

Task 2 will reanalyze available aquifer test data using analysis techniques focused on confining layer properties. Table 1 summarizes some of the known aquifer tests conducted on wells that may have been sealed to the confining layer. Most of these aquifer tests and analyses were not focused on confining layer properties. In addition, longer term operational tests were conducted on selected E/M and production wells with seals. Table 3, below summarizes the methods that will be used on the appropriate aquifer test and water level data in Table 1 and the operational test data noted above, and the parameters of the confining layer that may be derived. Every appropriate method will be used in the analyses. In addition to aquifer test data, driller’s logs and geophysical logs will be required of the pumped and observation wells. Several methods could be combined to obtain storage values as was done by Leahy (Leahy, 1976). Leahy used Hantush’s 1960 solution (Hantush, 1960) and the Witherspoon and Neuman ratio method (Witherspoon and Neuman, 1967) to develop values of hydraulic conductivity and storage of the confining layer. Under certain conditions, water level data alone, without pumping, may be used to define properties of the confining layer (Neuman and Gardner, 1989). Several finite difference models may also be applied using the groundwater simulation codes MODFLOW (MODPUMP) or HST3D (Hutchison and Trommel, 1992). Task 2 will be conducted jointly by Inyo County and LADWP.

Table 3. Selected Aquifer Analyses Methods with Capability of Confining Layer Characterization.

Flow Method Reference Parameters of Confining Unit Outline of Method Computer Package
Steady State-Analytical Solutions De Glee’s (De Glee, 1930,1951) Vertical Hydraulic Conductivity (Kruseman and de Ridder,1990) ADEPT, 1995
Hantush-Jacob (Hantush and Jacob, 1955 ; Hantush, 1956,1964) Vertical Hydraulic Conductivity (Kruseman and de Ridder,1990) INFINITE EXTENT
Unsteady-State Flow Analytical Solutions Walton’s Method (Walton, 1962) Vertical Hydraulic Conductivity (Kruseman and de Ridder,1990) INFINITE EXTENT, AQUITEST FOR WINDOWS.
Hantush-Jacob (Hantush and Jacob, 1955) Vertical Hydraulic Conductivity AQTESOLV Manual AQTESOLV for Windows, 1997 ADEPT, 1995, TSLEAK.
Hantush’s Inflection Point- Method (Hantush, 1956) Vertical Hydraulic Conductivity (Kruseman and de Ridder,1990) Kasenow and Pare, 1994, WRPADEPT, 1995.AQUIX-2S
Hantush’s Curve Fitting Method (Hantush, 1960) The Product of Vertical Hydraulic Conductivity and Storage (Kruseman and de Ridder,1990) AQTESOLV for Windows, 1997 AQUIX-2S.
Flow Method Reference Parameters of Confining Unit Outline of Method Computer Package
Lai and Su, (Lai and Su, 1974) Vertical Hydraulic Conductivity (Dawson and Istok, 1991) ?
Moench Solution for a test in a Leaky Aquifer (Moench, 1985) Vertical Hydraulic Conductivity, Storage Coefficient AQTESOLV Manual AQTESOLV for Windows, 1997
Finite Difference Aquifer Test Analysis MODPUMP Hearn Scientific Software Pty Ltd Vertical Leakage MODPUMP Manual MODPUMP
HST3D (Hutchison and Trommer, 1992) Vertical Hydraulic Conductivity (Kipp, 1986) HST3D
Methods That Don’t Involve Pumping Neuman and Gardner (Neuman and Gardner, 1989) Vertical Diffusivity of the Aquitard ? ?

 

PHASE II

Task 3: Measurement of Vertical Groundwater Velocity from Temperature Profiles in Wells and Calculation of Vertical Hydraulic Conductivities using Head Measurements.

Stallman (Stallman, 1963), presented equations for the simultaneous flow of heat and groundwater, and suggested that the measurement of vertical groundwater temperature profiles might provide a useful method for estimating groundwater velocities. Bredehoeft and Papadopoulos (1965) provide a solution of Stallman’s equations for one-dimensional, vertical, steady flow of groundwater and heat. They provide a set of type curves whereby groundwater velocities can be calculated from temperature data. If head measurements are also available, their method can be used to calculate vertical hydraulic conductivities.

Temperature logs from a borehole have been used to determine vertical movement of groundwater in multiple applications ( Cartright, 1970, Keys and MacCary, 1971; and Sorey, 1971). From a practical standpoint, the precision of the borehole measurements was 0.01 degree Centigrade and the method was restricted to groundwater velocities sufficient to cause a measurable curvature in a temperature log. Candidate wells in Owens Valley for this analysis would include those sealed to a confining layer and the 10 multiple completion wells throughout the valley. Multiple completion or deep monitoring wells would be preferable, since pumps would have to be pulled on production or E/M wells.

The method would be applied to a single well first as a feasibility test. If not feasible, the method would be discontinued.

Task 3A: Tracer Method: LADWP TO PROVIDE SUITABLE REFERENCES ON THE METHOD. FEASIBILITY TO BE DETERMINED.

Task 4: Conduct New Drilling and Aquifer Tests to Determine the Characteristics of the Confining Layer.

Many methods exist for measuring the vertical hydraulic conductivity and storage coefficient of confining materials if the Tasks 2 and 3 cannot sufficiently characterize the confining materials. Core drilling will be conducted and direct measurements can be made of cores of the confining materials using laboratory methods approved by ASTM (American Society for Testing and Materials). Single well tests are available, many utilizing packers (Burns, 1969; Prats, 1971; Hirassaki, 1974; Bredehoeft and Papadopulos, 1980). Tests and analysis methods utilizing two or more wells have been reviewed above in Table 3 (De Glee, 1930,1951; Hantush and Jacob, 1955,; Hantush, 1956, 1960,1964; Walton, 1962; Neuman and Witherspoon, 1972; Lai and Su, 1974; Moench, 1985). Aquifer tests can be reconducted with installation of monitoring wells specifically for particular analysis methods aimed at confining material characterization. Methods of evaluating vertical ground water movement are summarized in several reports by Javandel (Javandel,1983 and 1984).

More specifically, drilling would be concentrated in areas where confinement has already been empirically proven (i.e. Big Pine, Thibaut Sawmill). At least three new test sites in these areas are proposed.

Materials Needed:

Task 1: Sensitivity Analysis of the Coupled Aquifer Model of Denis and Motz (Denis and Motz, 1998).

The computer programs and data are available for sensitivity analysis of an application to E/M 375 in the Big Pine wellfield at the Inyo County Water Department.

Task 2: Analyses of Available Aquifer Test Data

Basic LADWP and GBUAPCD aquifer test and lithologic and geophysical log data from aquifer tests, operational tests, DRI aquifer tests and Cabin Bar, Cottonwood well and Western Water aquifer tests. As-built drawings of all relevant pumped and monitoring wells. Aquifer test reports from LADWP, Inyo County, GBUAPCD and consultants.

Software for Aquifer Test Analyses- The Inyo County Water Department has AQTESOLVTM for Windows (HydroSOLVE, Inc., 1997) and software to conduct Hantush’s Inflection Point Method (Kasenow and Pare,1994) as well as WHIP (Well Hydraulics Interpretation Program) Version 3.22 (HydroGeo Chem, Inc. ,1988) and the Graphical Well Analysis Package Version 1.2 (Groundwater Graphics, 1986). TSLEAK (IGWMC, 1985) from the International Groundwater Modeling Center, and the commercial packages ADEPT, INFINITE EXTENT, MODPUMP, and the U.S.G.S. model HST3D should be acquired.

Task 3: Measurement of Vertical Groundwater Velocity from Temperature Profiles in Wells and Calculation of Vertical Hydraulic Conductivities using Head Measurements.

Temperature logging capability in two inch or greater diameter holes to 0.01C (Centigrade) resolution and a depth of approximately 750 feet (Contractor or Equipment Purchase). Drillers logs, geophysical logs and as-built diagrams of all relevant wells (LADWP). Coincident water level measurements in all wells using Inyo County water level equipment.

Task 4: Conduct Drilling and Aquifer Tests Aimed at Determining the Characteristics of the Confining Layer.

This task would require a drilling contractor, core equipment, a geophysical logging contractor, packers, portable pumps, e-tapes and pressure transducers, aquifer test analysis capability (software). A variety of contractors are available to provide well construction services, core equipment, packers and portable pumps.

Schedule:
See Figure 1 for a preliminary proposed schedule. Note that if characterization of the confining layer is adequate at any time after task two, the project will be concluded with the summary report.

Products:
Task 1: A report summarizing the sensitivity of the Denis and Motz Model. Recommendations on which parameters of the confining layer need the greatest emphasis in characterization and which could be reasonably estimated.

Task 2: A report documenting the data used, the analyses performed and the confining layer properties developed.

Task 3. A report documenting the temperature profiles measured, the analyses performed and the confining layer properties developed.

Task 4. A report documenting the additional drilling, coring, laboratory and aquifer tests performed and the confining layer properties developed.

Summary Report:
A summary report that includes a GIS (Geographic Information Systems) layer with confining property locations and attributes. A comparison of past modeling effort values with those derived in the cooperative study.

References:

ADEPT, 1995, Commercial Aquifer Test Package, CHESS Inc.

Blevins, M.L., Coufal, G.L., and D.S. McKeown, 1984, Owens Valley, California, Baisn Management from a Different Perspective. Paper given at the NWWA conference on Ground water management, Orlando, Florida, October 29-32, 1984.

Bredehoeft, J.D., and S.S. Papadopulos, 1980, A Method for Determining the Hydraulic Properties of Tight Formations, Water Resources Research, 16(1), pp. 233-238.

Brederhoeft, J.D., and S.S. Papadopulos, 1965, Rates of Groundwater Movement Estimated from the Earth’s Thermal Profile: Water Resources Research, v. 1, no. 2, pp. 325-328.

Burns, W.A., Jr., 1969, New Single-Well Test for Determining Vertical Permeability, Transactions of the AIME, vol. 246, pp. 743-752.

Cartright, K., 1971, Groundwater Discharge in the Illinois Basin as suggested by Temperature Anomalies, Water Resources Research, v.6, no. 2, pp. 912-918.

CH2M Hill,1991, Report on the Hydrology Study for the Owens Lake California Soda Ash Project. Prepared for Vulcan Chemicals. February, 1991.

City of Los Angeles and Inyo County, 1987, Feasibility of Sealing the Upper Zones of Existing Production Wells in the Owens Valley.

Coufal, E.L., W.R. Hutchison, T.E. Griepentrog and R. Jackson, 1991, Deep Test Hole Study: a report to the Inyo/LADWP Standing Committee from the Inyo/LADWP Technical Group. December 1991

Danskin, W. R., 1988, Preliminary Evaluation of the Hydrogeologic System in Owens Valley, California. USGS Water-Resources Investigations Report 88-4003.

Danskin, in Press, Numerical Evaluation of the Hydrologic System and Selected Water-Management Alternatives in Owens Valley, California USGS Water-Supply Paper 2370-H (Preliminary report draft, subject to revision).

Dawson, K.J., and Istok, J.D., 1991, Aquifer Testing: Design and Analysis of Pumping and Slug Tests. Lewis Publishers, Inc, Chelsea, Michigan.

De Glee, 1930, Over grondwaterstromingeen bij wateronttrekking door middel van putten. Thesis. J. Waltmena, Delft (The Neterlands), 175 pp.

De Glee, 1951, Berekeningsmethoden voor de winning van grondwater. In: Drinkwatervoorziening, 3e Vacantiecursus: 38-80 Moorman’s periodieke pers, The Hague.

Denis, R.E. and Motz, L.H., 1998, Drawdowns in Coupled Aquifers with Confining Unit Storage and ET Reduction. J. Ground Water, 36(2), 201-207, March-April 1998.

Groundwater Graphics, 1986, Graphical Well Analysis Package, Version 1.2 User Manual. Groundwater Graphics, San Diego, California.

Hantush, M.S., and C.E. Jacob, 1955, Non-steady Radial Flow in an Infinite Leaky Aquifer. Transactions, American Geophysical Union, Vol. 36, No. 1, pp. 95-100.

Hantush, M.S., 1956, Analysis of Data from Pumping Tests in Leaky Aquifers. Transactions, American Geophysical Union, Vol. 37, No. 6, pp. 702-714.

Hantush, M.S., 1960, Modification of the Theory of Leaky Aquifers. J. Geophys. Res. Vol. 65, pp. 3713-3725.

Hantush, M.S., 1964, Hydraulics of Wells. In Chow, B.T. Ed., Advances in Hydroscience. Vol. 1. Academic Press. New York/London. pp. 281-442

Harrington, R. F., 1998, Internal Inyo County Water Department Memorandum on the Continuation of the E/M 375 and E/M 382 Operational Testing. April 9, 1998.

Hirasaki, G.J., 1974, Pulse Tests and other early Transient Pressure Analyses for in-situ estimation of Vertical Permeability, Transactions of the AIME, Vol. 257, pp. 75-90.

Hollett, K.J., et al, 1991, Geology and Water Resources of Owens Valley, California, USGS Water-Supply Paper 2370-B.

Hutchison, C.B. and J.T. Trommer, 1992, Model Analysis of Hydraulic Properties of a Leaky Aquifer System, Sarasota County, Florida. United States Geological Survey Water-Supply Paper 2340.

Hutchison, W.R., 1986, Analysis of Well and Aquifer Tests: Wells 374 and 375 Big Pine Area. Inyo County Water Department Report 86-5, September, 1986.

Hutchison, W.R., 1986, Aquifer Test Results Enhancement/Mitigation Wells Owens Valley 1986-1987. Inyo County Water Department Report 86-6. May, 1987.

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