Letter forwarding a copy of the review for each of the ... · X J4 WMGT DOCUMENT REVIEW SHEET FILE #: DOCUMENT #: USGS-OF-85-484 DOCUMENT: Benson, L.V. and McKinley, P.W., 1985, Chemical

.1Z I I

WILLIAMS & ASSOCIATk, INC.8-F,>CB.-OX j$, 6Vj;aho 83872 (208) 883-0153 (208) 875-0147

Hbrdrogeology * Raeources Waste Management a Geological Engineering * Mine Hydrology

86 JUN-2 P1.56

May 309 1986Contract No. NRC-02-85-008Fin No. D-1020Communication No. 60

Mr. Jeff PohleDivision of Waste ManagementMail Stop 623-SSU.S. Nuclear Regulatory CommissioiWashington, D.C. 20555

RE: NTS

Dear Jeff:

VWy P ro i ct"/).Doc'ket. No.

P D

PRe~! 61-tI013.S

A copy of the review of each of the following documents isenclosed.

1. Benson, L.V., and McKinley, P.W., 1985, Chemical Compositionof Groundwater in the Yucca Mountain Area, Nevada, 1971-84.USGS Open-file Report 85-4e4, Denver.

2. Byerlee, J., Morrow, C.! and Moore, D., 1983, Permeabilityand Pore Fluid Chemistry of the Bullfrog Tuff in aTemperature Gradient. U.S.D.A. Geological Survey, USGS-OF-83-475.

3. Erdal, B.R.0 and others, November 16, 1981, Nuclide MigrationField Experiments in Tuff, 6 Tunnel, Nevada Test Site.International Symposium on the Scientific Basis for NuclearWaste Management Materials Research Society, -Boston, Mass.,LA-UR-81-3141.

4. Langkopf, BS_, August 1982, Thermal Analysis of NuclearWaste Emplacement in Welded Tuff. Sandia NationalLaboratories, Albuquerque, NM, SAND8O-2639.

5. Lappin, A.R.9 and Nimick, F.B., April 1985, Bulk and ThermalProperties of the Functional Tuffaceous Beds in Holes USW 6-1, UE-25a#1, and USW B-2, Yucca Mountain, Nevada. SandiaNational Laboratory, Albuquerque, NM, SAND82-1434.

6. Martinez, M.J., January -1985, FEMTRAN-A Finite ElementComputer Program for Simulating Radionuclide TransportThrough Porous Media. Sandia National Laboratory,Albuquerque. NM, SAND84-0747.

-860612073603

1~-102O PDR '309I

7. Moore, D.E., Morrows C.A., and Byerlee, J.D., June 1984.Changes in Permeability and Fluid Chemistry of the TopopahSpring Member of the Paintbrush Tuff (Nevada Test Site) WhenHeld in a Temperature Gradient: Summary of Results.Lawrence Livermore National Laboratory, UCRL-15620, SANL 324-001.

S. Moore, D.E., Morrow, C.A., and Byerlee, J.D., 1984,Permeability and Fluid Chemistry Studies of the TopopahSpring Member of the Paintbrush Tuff, Nevada Test Site, PartII. U.S.D.I. Geological Survey, USGS-OF-84-848.

9. Peters, R.R.v Gauthier, J.H., and Dudley, A.L., 1985, TheEffect of Percolation Rate on Water Travel Time in Deep,Partially Saturated Zones. Sandia National Laboratory,Albuquerque, NM, SAND85-0854C.

10. Sass, J.H., Lachenbruch, A.H. and Mases, C.W., 1980,Analysis of Thermal Data from Drill Holes UE25a-3 and UE25a-1, Calico Hills and Yucca Mountain, Nevada Test Site.U.S.D.I. Geological Survey, USGS-OF-80-826.

11. Waddell, R.K., Robison, J.H., and Blankennagel, R.K., 1984,Hydrology of Yucca Mountain and Vicinity, Nevada-California--Investigative Results Through Mid-1983. USGS Water ResourcesInvestigations Report 64-4267.

Please contact me if you have any questions concerning thesereviews.

Sincerely,

Jim Osiensky

JO:sl

enclosures

X J4

WMGT DOCUMENT REVIEW SHEET

FILE #:

DOCUMENT #: USGS-OF-85-484

DOCUMENT: Benson, L.V. and McKinley, P.W., 1985, ChemicalComposition of Groundwater in the Yucca Mountain AreasNevada!, 1971-84. USGS Open-file Report 85-484,Denver, 10 p.

REVIEWER: Williams & Associates, Inc.

DATE REVIEW COMPLETED: May 28, 1986It I

ABSTRACT OF REVIEW: APPROVED BY:

The report under review presents water chemistry data for 25groundwater samples collected from 15 test wells in the vicinityof Yucca Mountain. The data indicate that sodium is the mostabundant cation and bicarbonate is the most abundant anion in allwater samples. Uncorrected radiocarbon ages of water fromvolcanic tuffs within 1 km of the exploratory block on YuccaMountain ranged from 12,000 to 18,500 years B.P.

BRIEF SUMMARY OF DOCUMENT:

The report under review presents chemical analyses of 25groundwater samples collected from 15 wells in the vicinity ofYucca Mountain. The water chemistry data are presented in Table1 of the report. The water chemistry data indicate that sodiumand bicarbonate ions, respectively are the predominant cationand anions. Water chemistry data for the deep carbonate aquiferpenetrated by test well UE-25p#1 indicate that total dissolvedsolids concentrations are greater than that for water from thetuffaceous rocks; in addition, groundwater in the deep carbonateaquifer contains higher concentrations of calcium, magnesium,chloride and sulfate. Based on variation in the concentrationsof inorganic constituents and of stable and radioactive isotopesthe report concludes that a significant: degree of lateral andvertical chemical heterogeneity exists in the groundwater of theYucca Mountain area.

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According to the reports uncorrected radiocarbon age data for thegroundwater within 1 km of the Yucca Mountain exploratory blockranged from 12,000 to 18,500 years B.P. According to the report,oxygen concentrations ranged from -12.8 to -14.2 o/oo; deuteriumconcentrations ranged from -93.0 to -106 o/oo4

SIGNIFICANCE TO NRC WASTE MANAGEMENT PROGRAM:

The report under review presents basic geochemistry data forgroundwater samples collected in the vicinity of Yucca Mountain.The report is significant with respect to the NRC WasteManagement Program in that it presents in tabular form thechemical analyses of 25 groundwater samples collected in thevicinity of Yucca Mountain.

PROBLEMS. DEFICIENCIES OR LIMITATIONS OF REPORT:

The report under review contains no significant problems,deficiencies, or limitations. The report is a basic data reportthat does not present interpretations of the data.

SUGGESTED FOLLOW-UP ACTIVITIES

Data reports of this kind should be reviewed so the NRC can keepcurrent records of the data available.


FILE X:


DOCUMENT: Permeability and Pore Fluid Chemistry of the BullfrogTuff in a Temperature Gradient: Summary of Results.J. Byerlee, C. Morrow and D. Moore, U.S.D.A.Geological Survey.


DATE REVIEW COMPLETED: May 28, 1986


Permeability and water chemistry changes associated with waterflowing through heated samples of the Bullfrog Member of theCrater Flat tuff were investigated. Small cylindrical sampleswith a heating element in the center were used for theexperiment. Water flowed radially due to a small pore pressuregradient. The pressure gradient was assumed- to be constant,which is not a valid assumption. This assumption will result ina slightly incorrect value of permeability. A significant changeof permeability occurred over time. The project was conductedunder saturated conditions which is not applicable to theproposed repository location.

BRIEF SUMMARY OF DOCUMENT:-

This report investigates the permeability and fluid chemistry ofwater that was forced to flow through heated samples of theBullfrog Member of the Crater Flat tuff. Cylindrical samples,7.62 cm in diameter and 8.B9 cm long with a 1.27 cm diameterhollow borehole in the middle were used in the experiment. Acoiled resistance heater was placed in the borehole to produce atemperature gradient between the center and the outside of thecore. Water flowed radially through the tuff from the centertoward the outside in response to a small, imposed pore pressuregradient. For the calculation of permeability the authors usedthe Darcy equation., but the pressure gradient in the radial

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direction was assumed to be constant. This assumption is notvalid for radial flow. The measured permeability of two out ofthree samples decreased with time. The maximum permeabilitymeasured was 10 microdarcies while the minimum was about .5microdarcy.

The mineral-fluid interactions seemed insufficient to account forthe high concentrations of dissolved material contained in theroom temperature fluids. A rapid decrease in concentrations ofmany of the dissolved species suggests also the removal of afinite amount of readily leached material rather than continuousmineral reaction. The permeability tests showed that asignificant decrease in permeability occurred with time comparedto that measured in some other rocks. This characteristic isdesirable because it may prevent downward percolatinggroundwaters from accumulating around the canisters. However, inthe proposed repository the pore matrix will be unsaturated;these samples were tested under saturated conditions.


Useful data probably are presented in this paper concerning theeffect of heated water on the permeability of the porous matrix.The data may be useful in the design of the waste repository.


A limitation of this work is that it was conducted undersaturated conditions whereas the repository in Yucca Mountainwill be under unsaturated conditions. Another deficiency in theexperimental work was that the pressure gradient during radialflow was assumed to be constant; this assumption will produce anincorrect value of permeability.


No follow-up is necessary.

! v- ; V Itr : I


FILE #:

DOCUMENT #: LA-UR-81-3141

DOCUMENT: Nuclide Migration Field Experiments in Tuff, G Tunnel,Nevada Test Site. B.R. Erdal, K. Wolfsberg, R.S.Rundberg, and W.R. Daniels (Los Alamos NationalLaboratory, Los Alamos, NM), D.L. Fortney and K.L.Erickson (Sandia National Laboratory, Albuquerque, NM)and A.M. Friedman, S. Fried, and J.J. Heinz (ArgonneNational Laboratory, Argonne, IL), submitted toInternational Symposium on the Scientific Basis forNuclear Waste Management Materials Research Society,Boston, Mass., November 16, 1981.



ABSTRACT OF REVIEW: APPROVED BY: IT% I j

This report considers a proposedthe Nevada Test Site. Thedevelop techniques for definingfractured rock. Fractures -iisaturated by injection of water.will be investigated. The flow chorizontal plane at saturatedvertical plane at unsaturatedMountain.

insitu experiment in G tunnel onpurpose of the experiment is toradionuclide migration throughI a horizontal plane will beThe movement of tracers thenf -water will be essentially in aconditions rather than in aconditions such as in Yucca


The factors which will go into selecting a repository site arediscussed in this report. The authors discuss the necessity fordetermining concentration and travel times for radionuclides thatmay leave a repository and the need for predictive models basedon the understanding of the dynamic processes that occur at eachlocation in the repository system. The analysis for the flow inthe repository is being conducted by Los Alamos National

2

Laboratory, Sandia National Laboratory and Argonne NationalLaboratory. The three principal objectives of the work in thereport under review are:

"1) to develop the experimental instrumental andsafety techniques necessary to conduct controlledsmall-scale radionuclide migration fieldexperiments,

2) to use these techniques to define radionuclidemigration through rock by performing generic, atdepth experiments under closely controlledconditions in a single fracture in a porous rock,and

3) to determine whether available lithologic field,chemical and hydraulic properties together withexisting or developed transport models aresufficient and appropriate to describe real fieldconditions."

The site for one field experiment is in tuff exposed in B Tunnelat the Nevada Test site. A single fracture will be used becausethe emphasis of the project is on flow and element migration.The authors state that "the bedding/parting plane was selectedfor use because a horizontal flow system was preferred for theseinitial experiments. It is felt that the-- system could becontrolled better in a horizontal than in a vertical system." Wesuggest that it may be easier to control flow in the verticaldirection than in horizontal direction if the region isunsaturated such as in Yucca Mountain. The reason is that steadystate downward flow can be achieved 'in the vertical directionwhereas it cannot be achieved easily in the horizontal plane.The authors state subsequently that "prior to injection oftracers groundwater will be injected for sometime to fullysaturate the rock and establish steady state flow." Actually itis very difficult to saturate a rock completely or attaincompletely steady state flow. The authors also mention sheetflow but they do-not define the meaning of such flow.

The remainder of the paper constitutes a detailed discussion of aparticular experiment and the suitability of various tracers foruse in a fractured porous medium. In addition variousmathematical models which would be needed are considered. Insummary, this paper is a review of the factors that enter intothe characterization of the site.

- qI

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This paper has no apparent significancerepository in Yucca Mountain since it isresearch that has been done, but rather it isexperiment.

for the proposednot reporting on

proposing an insitu


The work proposed herein would be conducted at saturatedconditions (water is injected until rock is saturated) whereasYucca Mountain is unsaturated.


No follow-up activities are suggested.

._ . ; -. e

WMGT DOCUMENT-REVIEW SHEET

FILE #:

DOCUMENT #: SANDBO-2639

DOCUMENT: Thermal Analysis of Nuclear Waste Emplacement inWelded Tuff. -B.S. Langkopf, prepared by SandiaNational Laboratoriesv Albuquerque, NM, for the U.S.Dept. of Energy, August 1982.


DATE REVIEW COMPLETED: May 286 1986

: 5 ,~~~~~~~~~~~~~~

ABSTRACT OF REVIEW: APPROVED BY: c z7.

Thermal analysis for a repository 300 m below the water table isconsidered theoretically in this report. Results are presentedas graphs of temperature rise vs. distance above and below therepository. Since the present proposed repository is over 300 mabove the water table, the information presented in the report isnot relevant.


The objectives of this work are:

"1) to define the anticipated environment for arepository in welded tuff either above or belowthe water table.

2) to identify both model and data needs forconfident design of repository in welded tuff.

3) to develop conceptual test plans for insitu teststo resolve the issues identified above.

4) to integrate results of insitu tests andlaboratory modeling studies into an engineeringdesign data package for use in the conceptualdesign of repository."

2

This paper examines the thermal analysis of a repository locatedbelow the water table. Calculations are carried out for variousrepository geometries for the very near field. Various wasteforms are considered also.. The repository was assumed to be 330m below the water table, and 50 m below the contact between theBullfrog and.Prow Pass Members of the Crater Flat tuff.

Thermal convection was not modeled. Thermal radiation wasmodeled in the air gap between the canister and the borehole wallby using an "effective" thermal conductivity. Two dimensionalmodels were used for the far field calculations and two and threedimensional models were used for near field and very near fieldcalculations. Results are presented in the form of graphs oftemperature rise vs. depth above and below the repository.Isotherms of the temperature distribution and the variousconfigurations are presented also. The highest temperature to beexpected at the canister is determined to be 295-C. Room andpillar three-dimensional calculations show that temperatures inthe room and pillar configuration should remain below 120CC.


The calculations in this report are for a repository below thewater table. The value of this information in the presentrepository is limited.


The report has severe limitations with respect to application toYucca Mountain because the proposed repository is in theunsaturated flow zone and the present report containscalculations for 300 m below the water table.


We suggest no follow-up activities.

K,


FILE #:-

DOCUMENJ #: SAND82-1434

DOCUMENT: Bulk and Thermal Properties of the FunctionalTuffaceous Beds-in Holes USW G-1, UE-25a#1. and USW 6-2, Yucca Mountainv Nevada. A.R. Lappin, EarthSciences Division and F.B. Nimick, NNWSII, GeotechnicalProjects Division, Sandia National Laboratory,Albuquerque, NM, April 1985.



ABSTRACT OF REVIEW:

I I

APPROVED BY: ri -A-

Bulk and thermal property data are presented for one of four tuffunits that initially were being reviewed for the location of thehigh level waste repository in Yucca Mountain. The tuffaceousbeds of the Calico Hills unit are reviewed. Lithologic logs,mineralogic analyses downhole density logs and bulk propertymeasurements were used for the characterization of the unit.Measurements were made at boreholes USW G-1 and USW G-2. Datafrom this report could be used for thermal-mechanical modelingstudies of the repository. The proposed repository is not in theunit studied in this report.


An evaluation is conducted of the relative merits of four tuffunits at Yucca Mountain as candidate horizons for the repository.This report documents bulk and thermal property data used inevaluating the tuffaceous beds of the Calico Hills unit. Theaverage thermal properties vertical distribution of bulkproperties and estimated uncertainties in all measurements aredefined. The tuffaceous beds include the lower zeolitized ashflow top in the overlying Topopah Spring Member of the Paintbrushtuff, the zeolitized upper portion of the ash flow top and theunderlying Prow Pass unit of the Crater Flat Tuff. These

2

functional tuffaceous beds are more complex and thicker than theash flow portions of the tuffaceous beds of the Calico Hillsunit. Four sources of data used to distinguish these beds are:1) lithologic logs, 2) mineralogical analyses, 3) downholedensity logs, and 4) bulk property measurements. The overallthickness of the tuffaceous beds ranges from 143 m in USW G-i to312 m in borehole USW G-2. The upper sub unit ranges from 104 to312 m. Frequency distribution data for the grain density andporosity serve as input to the sensitivity analysis that relatedthe predicted excavation stability to variations in tuffproperties. Results show that the cumulative frequencydistribution of porosity in this formation shows little variationamong holes. Thermal conductivities have been measured from 13strongly zeolitized tuffs from the two holes; the values do notdiffer significantly. No correlation between grain density andmatrix conductivity is apparent. Thermal expansion is animportant parameter in the analysis for waste emplacement; italso is a major factor in the control of thermally inducedstrains. The thermal expansion behavior of zeolitized tuff isexpected to be quite complex because of the presence of one ormore hydrated phases. The structural state of the tuffs maydepend on both temperature and relative humidity due to theoccurrence of clay. The authors state in summary that "dataprovided in this report are intended to serve largely as a basisfor near field and/or very near field thermal mechanical modelingstudies based on average properties and sensitivity analyses tobe performed as part of evaluated potential repository horizonsin tuff. The amount of data is limited in all cases. Theapproach taken demonstrates a method by which other requiredfunctional stratigraphies can be developed."


This report presents a study of the thermal and mechanicalproperties of the zeolitized tuffs which probably will be of usein determining the structural characteristics of the repository.However the proposed repository would not be located in thematerial which was investigated.


No limitations in the analysis are obvious.

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Engineers designing the repository should be made awaredata included in this report on structural andcharacteristics of the Calico Hills tuff.

of thethermal

4 -.


FILE ::

DOCUMENT #: SAND84-0747

DOCUMENT: FEMTRAN-A Finite Element Computer Program forSimulating Radionuclide Transport Through PorousMedia. M.J. Martinez, Sandia National Laboratories.Albuquerque, NM, January 1985.




FEMTRAN is a finite element computer code for numericalsimulation of two-dimensional transport of radionuclide decaychains through saturated/unsaturated absorbing porous media. Theprogram requires input of a velocity field from either of theprograms FEMWATER, MARIAH, or SAGUARO. Several optional solutionschemes are used in operation-of the program. The program isdesigned for the Cray IS computer. Comparison of simulationresults with analytical results show excellent agreement.


FEMTRAN is a finite element computer program for numericalsimulation of two-dimensional transport of decaying radionuclidesthrough saturated/unsaturated adsorbing porous media. Thetransport mechanisms considered include advection, hydrodynamicdispersion, diffusion, equilibrium and adsorption and radioactivedecay and evolution. The resulting equations are solved by themethod of weighted residuals and the finite element method. Theordinary differential equations are integrated in time bystandard finite difference methods such as Crank Nicholson,backward difference or central difference. In formulating thegoverning equations for radionuclide transport the Darcianvelocity field is assumed to be a known input. FEMTRAN requiresthe computation of Darcian velocities from the programs FEMWATER,MARIAH or SAGUARO which-are then used in the transport equations.

2

A large number of alternate numerical schemes are in use for theoperation of the program. These schemes are Crank Nicholsonbackward difference, mid difference, two different systems ofweighting functions, the Galerkin, and upstream and mass matrixlumping may or may not be used. The authors present limited userinstructions. The program is designed to be used on the Cray 16computer at Sandia National Laboratory. The authors presentseveral sample problems for comparison with analytical results.The comparison shows excellent agreement. User instructions arebrief but probably are sufficient for a person familiar with theCray computer and with similar numerical programs.


This program appears to be useful for determining the travel timeto the accessible environment if the solution for water flowvelocity is available, and if the actual water travel times arelarge enough that the time for adsorption and decay is notsignificant.


The most significant limitation appears to be the necessity forhaving a solution to the hydrodynamic equations before using theprogram.


No follow-up is necessary


FILE #:

DOCUMENT A: UCRL-15620v SANL 324-001

DOCUMENT: Changes in Permeability and Fluid Chemistry of theTopopah Spring Member of the Paintbrush Tuff (NevadaTest Site) When -Held in a Temperature Gradient:Summary of Results.- D.E. Moore, C.A. Morrow and J.D.Byerlee, Lawrence Livermore National Laboratory, June1984.



ABSTRACT OF REVIEW: APPROVED EB:Y

Permeability and heat flow experiments were conducted on smallcylindrical samples of tuff from the Topopah Springs and Bullfrogunits. The permeability of some samples increased due to heatingbut no change occurred in other samples. Water qualitymeasurements showed no change of pH when water flowed through theTopopah springs samples but an increase of pH up to 10.6 occurredwhen high temperature (250-C) water flowed through the Bullfrogtuff. The authors conclude that heating to 150°C causes littleeffect on permeability or water quality in the Topopah Springstuff.


Permeability experiments were conducted to determine the effectof heat from radioactive decay on tuffaceous rock. The objectivewas to measure the effects of localized heating around canisterson the permeability and chemistry of the rock and associatedgroundwaters. The two tuff units tested were the Bullfrog Memberof the Crater Flat tuff and the Topopah Spring Member of thePaintbrush tuff.

Cylindrical samples, 7.62 cm in diameter and 8.89 cm in lengthwith a 1.27 cm diameter drill hole in the center were tested. A

2

coiled resistance heater was placed within the hole in the centerof the core which produced a temperature gradient between thecenter and the outside of the core for permeability measurements.Water flowed radially through the tuff from the highertemperature center of the core to the lower temperature at theouter edge in response to a small pore pressure gradient appliedbetween the center and outside of the core. The water used inthe experiments was natural groundwater collected from the NevadaTest Site. The rock sample was thermally insulated on its sides.One sample of the Topopah Spring Member had an originalpermeability of 3 microdarcies but after undergoing heating to150 degrees the permeability increased to 8 microdarcies andultimately to approximately 10 microdarcies. The permeability ofa second sample of tuff remained between 60 and 70 microdarcieseven after heating to a borehole- temperature of 90-C.

Water samples were tested after flowing through the cylinders andanalyzed for 13 dissolved species. Values of pH for all of thefluid samples were between 6.9 and 8.1. Experiment one showed aslight trend toward decreasing pH with time and a tendency toincrease pH with- decreasing temperature. The dissolvedconstituents varied with time, in some cases increasing and inother cases decreasing.

Experiments similar to those in the Topopah Springs Member wereconducted on the Bullfrog Member. Initial permeabilities in theBullfrog samples ranged from .5 to 8.5 microdarcies and showedslight to obvious higher permeabilities upon initial heating.The increase was attributed to thermal cracking. In the highertemperature (250°C) experiments the permeabilities decreasedfollowing the initial increases, but eventually returned to theinitial room temperature values. Chemical tests on the watershowed pH values up to 10.6. Much larger amounts of dissolvedmaterial were observed than in fluids from the comparable Topopahexperiments. In their conclusion the authors state that heatingto temperatures of at least 150°C has little effect onpermeability. Interaction of the groundwater with the TopopahSpring Member caused only minor changes in water composition.


Information contained in the report on the heating effect on thetuffaceous material may be of interest when the actual repositoryis designed.

--- 41: --i . *

hid


A limitation on this experiment is. that it was done undersaturated conditions whereas the rock in the repository willdisplay unsaturated conditions. :The difference caused by thisfactor could be significant.


This work should be kept in mind -in case such information isneeded to design the waste repository.


FILE #:

DOCUMENT #: USGS-OF-84-e48

DOCUMENT: Permeability and Fluid Chemistry Studies of theTopopah Spring Member of the Paintbrush Tuff, NevadaTest Site, Part II. D.E. Moore, C.A. Morrow and J.D.Byerlee. U.S.D.I. Geological-Survey




This report is a continuation of work done previously by the sameauthors. The work concerns the effect of heat on permeabilityand on the chemical composition of water flowing through samplesof tuff. Three cylindrical samples of Topopah Springs tuff wereused in this study. Permeability was determined by- measuringradial flow in the cylinder under a-small pore pressure gradient.A temperature gradient also was maintained radially outward formthe center of the core. The results show essentially no changeof permeability with respect to pore -pressure, orientationstemperature changes or temperature gradient. The observed slightdecrease of pH with time may be due to the progressive removal ofsalt deposits from the tuff.

BRIEF SUMMARY OF DOCUMENT:.

This document reports on an extension of work done previously bythe same authors concerning the effect of heat on permeabilityand on the chemical composition of water flowing through samplesof tuff. The present experiment was conducted on three samplesof the Topopah Spring Member of the Paintbrush tuff. The sampleswere cylindrical cores containing a central borehole in which aresistance heater was placed to-produce a temperature gradientbetween the center and the outside of the rock. Water flowedradially due to a small pore pressure gradient applied betweenthe center and the outside of the cores The borehole temperature

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in all cases was maintained at 150C; the jacket temperature washeld at approximately 44-C. All three samples were run with apore pressure of 10 bars; This pressure represents the pressureat a depth of too m below the water table. The flow through twosamples was perpendicular to the bedding planes but flow wasparallel to the bedding planes in the other sample. The initialpermeability at room temperature varied from .85 to 10microdarcies in the three samples. Initial values of .5 to 8microdarcies occurred when heating began. The permeabilityexperiments were continued for a period of 10 to 16 days at whichtime little additional change in the permeability was occurring.The chemical analysis of water samples showed that in general adecrease of pH of water with time occurred, along with slightchanges of chemical species contents. The authors conclude thatthe combination of heat and fluids has little effect on thepermeability of the tuff. During the time of the experimentsalmost no permeability changes were observed. The results areindependent of confining and pore pressure and of sampleorientation. Changes in temperature and direction of fluid flowrelative to the temperature gradient also had no observed effecton permeability. The authors also conclude that the decrease inpH with time during each experiment -may be related to theprogressive removal of the salt deposits or saline pore fluidsfrom the tuff. The concentrations of chemical constituents inthe water in general decreased with time.


Some information in this report may be significant for theanalysis of flow through the Topopah Springs unit. However, itmust be noted that the present work was done under a porepressure of the equivalent of approximately 100 m of water whilethe repository in the Topopah Springs Member would be in theunsaturated zone well above the water table.


The limitation is that this work was done under a pore pressureof 10 bars or 100 m of water, not under unsaturated conditions.As stated above the repository will be in the unsaturated zonewell above the water table.

SUGGESTED FOLLOW-UP ACTIVITIES-

No response is necessary concerning this report.


FILE #:

DOCUMENT #: SAND85-0854C

DOCUMENT: The Effect of Percolation Rate on Water Travel Time inDeep, Partially Saturated Zones. R.R. Peters, J.H.Gauthier, and A.L. Dudley, Nevada Nuclear WasteStorage Investigations Project Department, SandiaNational Laboratory, Albuquerque, NM.



ABSTRACT OF REVIEW: APPROVED- PY: -

The report uses a computer code, TOSPAC, along with a conceptualmodel very similar to that used by Klavetter and Peters (1985).The model does not include the effect of vapor transport but itdoes treat the effect of compressibilities of the water, of theporous matrix and of the fractures on unsaturated vertical flow.

The code is used to determine the pressure, saturation levels,and velocity distributions for water percolation rates (fluxes)of .1, .5 and 4.0 mm/yr in Yucca Mountain. Two profiles areused; the first is for the Calico Hills vitrified unit; thesecond is for the Calico Hills zeolitized unit. Calculatedtravel times from the repository location to the water table areas low as three years for a flux of 4.0 mm/yr in the zeolitizedunit and 8400 years for the same flux in the vitric unit. Allother travel times are greater than 81,000 years.

This paper presents the most comprehensive treatment of traveltimes through the unsaturated zone at Yucca Mountain that we havereviewed.


The authors divide the hydrogeologic units of Yucca Mountain intothree groups: 1) densely welded tuffs that are highly fractured,

a

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2) nonwelded vitric tuffs that have few fractures, and 3)nonwelded zeolitized tuffs -that have few fractures. The firstset of tuffs (first group) has low assumed saturated matrixconductivity (10-LI m/s or less) and high assumed saturatedfracture conductivity (' 1 0 -' m/s). The second group has highassumed saturated matrix conductivity (10-4 to 10° ms) and lowassumed saturated fracture conductivity (1011 m/s).

The authors present a brief summary of the various flow rates ofwater through Yucca Mountain that have been reported in theliterature; they 'also present a short discussion of vapormovement. A mathematical model-and a computer program (TOSPAC)are developed and used in the report. The program does notconsider vapor transport, but it does -treat the effect ofcompressibility of water and of the-rock matrix. The authorsassume that Darcy's law is valid and that the pressure heads inthe fractures and the matrix are equal in a directionperpendicular to the flow lines. Van Genuchten's (1978)saturation vs. pressure head relationship and Mualem's (1976)conductivity vs. pressure head function are used in the program.The values of physical and hydraulic parameters used in thecalculations are from reports by Peters et al. (1984), Scott etal. (1983) and Sinnock et al. (1984). The data in these reportswere obtained from samples removed from Yucca Mountain. Theequation used in the mathematical model contains terms for thestorage of water due to the saturation of the matrix and thefracture systems, and terms representing compressibility of waterand dilation of the bulk rock. All these terms are functions ofthe pressure head in the water. The solution of the equationresults in determination of the pressure and saturation leveldistributions as well as the groundwater velocity and the waterflow rate (in the form of travel time) across the hydrogeologicunits of Yucca Mountain. The velocity also is a function of thepercolation rate and the composition (vitric or zeolitized) ofthe Calico Hills unit. The various coefficients in the equationare called capacitance coefficients. Curves are presented forthe coefficients as functions of pressure head. Compositeconductivity curves are presented for the Topopah-Springs and theCalico Hills nonvitrified unit. -These curves are presented ascurves for fracture conductivity, for matrix conductivity and thefor the composite conductivity.

Fluxes used in the simulation were .1, .5, and 4 mm/yr. Each ofthese rates was used with either the vitric or zeolitic portionsof the Calico Hills unit. The cases with an infiltration rateof .1 mm/yr assumed water movement only in the matrix throughoutthe hydrostratigraphic column. The cases with a rate-of .5 mm/yrdisplay a relatively small amount of water movement in thefractures of some units. The case with a 4 mm/yr rate reflect

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considerable water movement in the fractures in the Tiva Canyonand Topopah Spring units. Pressure head vs. distance above thewater table are plotted for the six cases studied. These graphsare similar to the analytical solution that can be obtained forunsaturated-flow through layered material.

Considerable discussion is presented about the changes ofcapillary pressure at interfaces and the appearance' of nearlydiscontinuous pressures in the aforementioned graphs. Pressuresin this situation are not discontinuous, but regions of very highpressure gradients do occur. Discussion also -is presented ofpossible errors in percolation-rates in these regions of largecapillary pressure gradients. However, the authors do notelucidate their reasons for concluding that percolation rates arein error in these regions. -The error is less than 5% and itcould be avoided completely if a finer computational mesh wereused. Curves of saturation level vs. distance above the watertable for the six cases also are presented. These curves alsoare similar' to those that would be obtained from an analyticalsolution of unsaturated flow through layered material. Thedegree of saturation is discontinuous at interfaces betweenunits.

The velocity of water flow-through the profile is plotted vs.distance above the water table. These curves indicate that thevelocity (2 to 5x1O010 m/s) in the Paintbrush Formation at a fluxof .1 mm/yr is higher than the velocity for a flux of either .5or 4 mm/yr. The value presented for a flux of .1 mm/yr isincorrect; the correct value is 6x10- 1 m/s. This velocity issmaller than that for a flux of 4 mm/yr but is still larger thanthe velocity for the flux of .5 mm/yr. This apparentcontradiction (higher flux and lower velocity) is caused by thedegree of saturation in the Paintbrush being higher than thatnecessary to transmit the specified flux under a potentialgradient of 1.0. This value of saturation is only slightlyhigher than 10/. and yet will transmit the specified flux at apotential gradient of-less than 1.0.

The authors discuss the groundwater travel time across thevarious units at Yucca Mountain and state that at a percolationrate of .1 mm/yr the water flow is confined entirely to thematrix in all but one unit. This statement is questionable. Itappears that the water would be confined to the matrix in allunits at this flow rate because the .1 mm/yr is considerably lessthan the saturated matrix conductivity of all units. The traveltime from the repository to the water table is calculated nextfor the three specified flow rates using the aforementioned twotypes of Calico Hills unit; the vitric and the zeolitized. Thetravel times are as low as three years for the flux rate of 4mm/yr through the zeolitized unit. The same flux rate throughthe vitric unit gives a travel time of 8,400 years. The

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calculations in this report appear to be reasonable with theexception of the one error mentioned above. However, this errorapplies to a unit above the repository location; consequently theerror would not affect the travel time to the accessibleenvironment.

SIGNIFICANCE TO NBC WASTE MANAGEMENT PROGRAM:

The results of this report show the absolute necessity fordetermining an accurate value for the percolation rate throughYucca Mountain; the paper demonstrates the high sensitivity ofthe travel time calculation to the flux rate. This is the mostlogical analysis conducted to date for the travel time from therepository location to the water table.


The limitation of this report is that the problem of flowvelocity was determined for only one value of each physical orhydraulic parameter in each unit. These parameters displayconsiderable variation is most rocks; the flow velocities shouldbe calculated using the extremes of the parameters to determinethe effect on calculated travel time. This report, however, is agood first step in the process of determining the minimum traveltime.


A research program should be pursued vigorously to determine thereal value of the percolation rate (flux) through Yucca Mountain.Such a program will be absolutely necessary to determine theminimum travel time.

K)

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REFERENCES CITED:

Peters, R.R. Klavetter$ E A., Hall I.J., Flair.- S.C., Heller.P.R., and Gee, G.W., 1984, Fracture and Matrix HydrologicCharacteristics of Tuffaceous Materials from Yucca Mountain,Nye County, Nevada. -Sandia National Laboratories,Albuquerque, NM, SAND84-1471.

Scott, R.B., Spengler, R.W., Lapping A.R.9 and Chornack, M.P.p1983, Geologic Character of Tuffs in the Unsaturated Zone atYucca Mountain! Southern Nevada. in Role of the UnsaturatedZone in Radioactive and Hazardous Waste Disposal. 3.Mercer, ed., Ann Arbor Science, Ann Arbor, MI.

Sinnock, S., Lin, Y.T., and Brannen, J.P., 1984, PreliminaryBounds on the Expected Postclosure Performance of the YuccaMountain Repository Site, Southern Nevada. Sandia NationalLaboratories, Albuquerque, NM, SAND84-1492.

van Genuchten, R., 1978, Calculating the Unsaturated HydraulicConductivity with a New Closed Form Analytical Model. WaterResources Bulletin, Princeton -University Press, PrincetonUniversity, Princeton, NJ.


FILE #:


DOCUMENT: Analysis of Thermal Data from Drill Holes UE25a-3 andUE25a-1 Calico Hills and Yucca Mountain, Nevada TestSite. J.H. Sass, A.H. Lachenbruch; and C.W. MaserU.S.D.I. Geological Survey, 1980.


DATE REVIEW COMPLETED: May 28t 1986 1

ABSTRACT OF REVIEW: APPROVED BY: 4

Temperature profiles were measured in borehole UE25a-3 in YuccaMountain and borehole UE25a-3 in the Calico Hills. The profilesshowed that upward or downward water flow below the water tablein Yucca Mountain is probable but it is not possible to determinewhether the flow is in the borehole or in the rock. Some of thevariations in the temperature profile may be due to variations inthe heat conductivity of the formation. No statement is madeconcerning vapor flux in the unsaturated zone.


This document reports on temperature profiles measured inborehole UE25a-1 in Yucca Mountain and borehole UE25a-3 in theCalico Hills stratigraphic unit. In Yucca Mountain the apparentheat flow above the water table is upwards, while-below the watertable a possible indication exists of upward or downward watermovement within the hole and possibly within the rock. Thetemperature profile within hole UE25a-1 shows a definitecurvature below the water table which indicates an almost certainupward flow of water within the hole or within the rock. Since adefinite indication of vertical water movement is present, theauthors analyzed the data from both a conductive and a convectivestandpoint. However, thermal conductivities in this boreholewere not measured. Thermal conductivities for hole UE25a-3 weremeasured on saturated cores of the Calico Hills unit. The linear

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segments of the temperature profiles were analyzed from thestandpoint of conductive heat flow. The conductivity used waseither the harmonic mean of the measured conductivities withinthat segment or an estimate based on measurements of the CalicoHills unit in other locations.

A one-dimensional upward or downward diffusion flow model wasused to calculate seepage velocity for the nonlinear temperaturedistribution segments. The authors state, however, that it isimpossible to determine whether the upward flow is in the rack orwithin the borehole. In one section of borehole UE25a-1, thetemperature profile is wavy, which suggests zones of both upwardand downward water movement. As stated by the authors, however,the possibility of variations in thermal conductivity alsoexists. The authors present considerable discussion of theregional temperature distribution -and point out that lateralvariations such as that which occurs between these two holes(UE25a-3 and UE25a-1) is characteristic of the Nevada Test Site.This large variation in heat flow between holes 1 and 3 couldsuggest the presence of a more deeply seated hydrothermalconvective system with net upward heat flow beneath the CalicoHills and a net downward flow beneath Yucca Mountain. Theauthors do not draw any conclusions concerning the flow of waterin the unsaturated zone in either hole. As stated previously,evidence of downward flow in hole I is present; however, thisdownward flow could constitute circulation in the hole ratherthan in the formation because the data base cannot differentiatebetween the two.


This report has been used as evidence that vapor flow may occurin the unsaturated region of Yucca Mountain. We find nothing inthis report from which to draw such conclusions. The onlyevaluation of water movement concerns the saturated flow region.


This report does not provide information to lead to anyconclusion concerning vapor movement within or beneath YuccaMountain.

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At the time the conceptual model report (Montazer and Wilson,1964) was reviewed, we were uncertain about the significance ofthe vapor movement in their conceptual model. After reviewingthis report it appears that the concept of vapor movement is evenmore uncertain than we have suggested in our previous review.


FILE #:

DOCUMENT #: USGS-WRI-84-4267

DOCUMENT: Waddell, R.K., Robison, J.H.0 and Blankennagel, R.K.,1984, Hydrology of Yucca Mountain and Vicinity,Nevada-California--Investigative Results Through Mid-1963. U.S.G.S. Water Resources Investigations Report84-4267, Denver, 72 p.


DATE REVIEW COMPLETED: May 28, 1986 ,9

ABSTRACT OF REVIEW: APPROVED En: §

The report under review presents investigative results for YuccaMountain and vicinity through mid-1983. Conceptual models forflow in the saturated zone are presented. These conceptualmodels are modified after the original models presented byWinograd and Thordarson (1975). Conceptual models presented inthe report under review include data not available to Winogradand Thordarson (1975). Conceptual models for flow in theunsaturated zone are not presented in detail becauseinvestigations up to mid-1983 were concerned primarily withpotential high level waste disposal within the saturated zone.

-BRIEF SUMMARY OF DOCUMENT:

Introduction

The purpose of the report under review is to present the USGShydrology contributions to the site characterization report ofthe Yucca Mountain area. A companion report (U.S. GeologicalSurvey, 1984) presents the geology of the Yucca Mountain area.These reports include data collected and analyzed through mid-1983. The report under review describes the hydrology within the"candidate area" prescribed by the Nuclear Regulatory Commission.The candidate area refers to the area contained within a 100 kmradius of Yucca Mountain.

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Surface-Water Hydrology

The candidate area includes most of the Death Valley BasinHydrographic Region of California-Nevada and a small part of theCentral Hydrographic Region of Nevada. These hydrographicregions are divided into smaller units called hydrographic areas.The Yucca Mountain site lies on the boundary between Crater Flatand Fortymile Canyon-Jackass Flats hydrographic areas.

The report describes briefly the data available pertaining toflood potential in the vicinity of Yucca Mountain. According tothe report, past severe flooding indicates that occasional severefloods probably will occur in the future within southern Nevada,and may occur at Yucca Mountain. The report under reviewpresents the following conclusions based on an investigation offlood potential in Topopah Wash by Christensen and Spahr (1980):

1. The 100 year flood-prone areas closely parallel most mainchannels.

2. The five-year flood would exceed the discharge capacity ofall stream channels except Topopah Wash and some upstreamreaches of a few tributaries.

3. The "maximum potential" flood would inundate most of JackassFlats.

Squires and Young (1984) studied the downstream part of FortymileWash. According to the report under review, Squires and Young(1984) concluded that:

1. The 100 year, 500 year, and "regional maximum" floods wouldstay within the confines of the wash.

2. Crested Butte Wash and Drill Hole Wash would have estimatedflood-water depths from 0.3 to 1.2 m in the stream channelduring the 100 year flood. The 500 year flood would exceedbank capacities at several reaches of the washes. The"regional maximum" flood would inundate all central flat-fanareas in the two watersheds.

3. The 100 year, 500 year, and "regional maximum" floods withinYucca Wash would stay within the steep-side-slope streambanks that contain the floodplain.

According to the report, most of Yucca Mountain is well aboveexpected flood levels; however, areas that are close to channelsor within the lower terraces of Fortymile Wash are,subject toflooding.

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Regional Groundwater Hvdrology

Discussion of the regional groundwater hydrology begins with adescription of the basic hydrogeologic units that occur withinthe candidate area. These hydrogeologic units from oldest toyoungest are: the lower clastic aquitard, the lower carbonateaquifer, the upper clastic aquitard, the upper carbonate aquifer,granite, volcanic rocks, and valley fill aquifer. A generaldescription of each of these units is presented in the report.

According to the reports recharge areas were estimated based onthe potentiometric map -(Plate 3 of the report) and thedistribution of precipitation. Areas of high precipitation wereconsidered to be the primary groundwater recharge areas. Theserecharge areas include the Spring Mountains, and the Sheep,Pahranagat, and Belted Ranges.

According to the report, groundwater discharge areas within thecandidate area are characterized by rocks of relatively lowerhydraulic conductivity that occur downgradient from the dischargeareas. The report suggests that a steep potentiometric gradientacross the low hydraulic conductivity rocks causes the watertable to intersect land surface whereupon groundwater dischargeareas are created. Plate 4 of the report shows the locations ofsprings within the candidate area. Major discharge areas arelocated along the Ash Meadows spring line, and at Alkali Flat(Franklin Lake), the Furnace Creek Ranch area, and Oasis Valley.Minor discharge areas from the regional aquifers are believed tooccur also at Indian Springs and Cactus Springs. According tothe report, numerous perched springs of minor and variabledischarge are present throughout the area.

The candidate area is located within the Death Valley groundwaterbasin. The authors of the report divide the Death Valleygroundwater basin into three groundwater subbasins. Thesesubbasins are: Oasis Valley, Ash Meadows, and Alkali Flat-Furnace Creek Ranch. According to the report, a subbasinconsists of recharge areas and flow paths to a major dischargearea. A description of each of the three subbasins is presentedin the report. However, it should be noted that the actualboundaries of each subbasin are not well defined. The boundariesof the subbasins are defined based on the locations of aquiferoutcrops, the distribution of precipitation, and topography.Essentially no hydraulic head data are available upon which todelineate the actual locations-of the boundaries.

A brief discussion of the isotopic and regional hydrochemistry ispresented in the report. The data indicate that most of thegroundwater samples collected to date have highly variable

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compositions. According to the report, mixing of waters fromcarbonate and tuffaceous sources is indicated by the chemistry ofwaters in parts of Ash Meadows and Alkali Flat-Furnace CreekRanch groundwater subbasins; mixing is evident especially beneaththe southern Amargosa Desert and near the Furnace Creek Ranch.According to the report, chemistry of the water beneath YuccaMountain probably is derived solely by reaction with tuffaceousrocks.

Carbon-14 ages for samples taken from test holes UE-29a#1 and UE-29a#2 in upper Fortymile Canyon are given as.4,100, 3,800, and2,280 years. According to the report, these carbon-14 agessuggest that recharge has occurred relatively recently alongmajor drainages. Most of the hydrogen and oxygen isotopic datapresented in Plate N of the report indicate that recharge waterprobably was derived from melting snow.

Yucca Mountain Hydroaeologic System

According to the report, two series of test holes were drilled todepths greater than a few hundred meters. In one series, smalldiameter core -holes were drilled to obtain stratigraphic,structural and physical-property data (UE-25a#l, UE-25b#l, USW6-1, USW G-29 USW G-3/GU-3. and USW 6-4). A second series oftest holes was drilled to obtain hydrologic data. A small amountof core was obtained from test wells USW H-1, USW H-3, USW H-4vUSW H-5, and USW H-6. According to the report, test holes UE-25b#1 and USW G-4 were cored and then reamed to allow forhydrologic testing. Four piezometers were installed at differentdepths in test well USW H-1 to measure the vertical headgradients within the test hole.

According to the report, concepts on water movement within theunsaturated zone are not well developed, in part because earlyhydrologic studies of Yucca Mountain concentrated on thesaturated zone. According to the report, additional data areneeded to answer the following questions (p. 47):

1. What is the rate of recharge, and how does it varyspatially and temporally?

2. Do the effects of capillary barriers inhibitmovement of water from porous tuffs throughfractures; if so, what potential gradients arenecessary to initiate flow in fractures in denselywelded tuffs?

3. If water moves in-fractures, how far can it travelbefore being drawn into the matrix?

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4. Does perched water occur-in-the unsaturated zone atYucca Mountain?

5. What would be the effect of increased recharge thatmight accompany a return to pluvial climaticconditions on movement of water within theunsaturated zone? In particular, what effect wouldthere be on travel time from a repository to thesaturated zone?

The report notes that both matrix and fracture hydraulicconductivity occur in the volcanic rocks in the vicinity of YuccaMountain. According to the report,.a zone of relatively intensefracturing and faulting on the southeastern and eastern sides ofYucca Mountain has been mapped. Another feature indicated bysurface mapping is that fracture density is less intense in thenorthern part of Yucca Mountain, where displacement and thenumber of faults are less than in the southern part. The reportnotes that aquifer test data are being analyzed to estimateinsitu hydraulic conductivity of rocks in the saturated zone;however, the report notes also that the data analyses areincomplete in part because a single unifying theory for analyzingaquifer tests in fractured rocks has not been developedsufficiently.

The report describes the distribution of groundwater recharge inthe vicinity of Yucca Mountain as a function of the amount anddistribution of precipitation, type of precipitation, conditionsat time of snow melt (if a snowpack is present), lithology andmoisture content of soil, vegetation, and topography. The reportnotes that data on the distribution of recharge at Yucca Mountaindo not exist. The report suggests that more recharge may occurbeneath the washes than beneath the surrounding ridges, becausewater is concentrated in washes during runoff events. Accordingto the report, the arid environment at Yucca Mountain and theabsence of large drainage basins indicate that recharge is verysmall. The report notes that data from Yucca Flat suggest thatlong-term average recharge rates probably are less than 5 mm/yr.Heat flow analyses in test well UE-25a#7 suggest that rechargemay occur in pulses rather than at a constant rate. over a longperiod of time.

Figure 8 of the report is a preliminary potentiometric surfacemap of the vicinity of Yucca Mountain. According to the report,measured head values used to construct the potentiometric maprepresent composite water levels. The potentiometric mapindicates that the hydraulic gradient is low in western JackassFlats (Fortymile Wash area) and in the Amargosa Dessert. Thepotentiometric map indicates that the gradient is high involcanic rocks north of Yucca Mountain and across northern YuccaMountain. The report notes that the potentiometric data

6

collected in conjunction with injection testing generally are notadequate to define vertical head gradients.

The report suggests that the potentiometric levels may be used toindicate the general directions of groundwater flow; consequentlythe general directions of the movement of radionuclides from arepository beneath Yucca Mountain should be obtainable from themap. The report suggests that flow beneath Yucca Mountainprobably is toward the southeast into the Fortymile Wash area andthen to the south toward the Amargosa Desert and Alkali Flatsthen toward Furnace Creek Ranch. The report notes however thatthe actual flow path that a particle of water would take may bemuch different from that indicated by the potentiometric map dueto heterogeneity and anisotropy.


The report under review presents a summary of the results ofhydrogeologic investigations conducted by the USGS in thevicinity of Yucca Mountain. The report summarizes the results ofhydrogeologic investigations completed through mid-1983.


The report under review represents the USGS contribution to/thehydrology portion of a site characterization report for the YuccaMountain area. The report presents general descriptions andanalyses of the hydrogeologic data collected at the YuccaMountain site. The report is not a highly technical discussionof the hydrogeology of Yucca- Mountain, but rather a generaldescription in layman terms of the basic USGS understanding ofthe hydrogeology.

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REFERENCES CITED:

Christensen, R.C.K and Spahr, N.E.. 1980, Flood Potential ofTopopah Wash and Tributaries, Eastern Part of Jackass Flats,Nevada Test Site, Southern Nevada. USGS Open File Report 80-963,22 p.

Squires, R.R., and Young, R.L.9 1964, Flood-plain Analysis ofFortymile Wash and Its Southwesternmost Tributaries, Nevada TestSite, Southern Nevada. USGS Water Resources InvestigationsReport 83-4001, 33 p.

U.S. Geological Survey, 1984, Summary of Geologic StudiesThrough January 1, 1983, of a Potential High-Level RadioactiveWaste Disposal Site at Yucca Mountain, Southern Nye County,Nevada. USGS Open File Report 84-792, 103 p.

Winograd, I.J., and Thordarson, J.W., 1975, Hydrogeologic andHydrochemical Framework, South-Central Great Basin, Nevada-California With Special Reference to the Nevada Test Site. USGSProf. Paper 712-C, 126 p.

Documents

Letter forwarding a copy of the review for each of the ... · X J4 WMGT DOCUMENT REVIEW SHEET FILE #: DOCUMENT #: USGS-OF-85-484 DOCUMENT: Benson, L.V. and McKinley, P.W., 1985, Chemical