Clinton.pdf | US EPA ARCHIVE DOCUMENTglacial clay tlls with intermitt°efcjt.10’.,._ •, tj’ — 1. this regional geologic cross sec11on is based on information from on—site

Cl,LUCD

I

60’ -

—600’

HORIZONTAL

GLACIAL CLAY TLLSWITH INTERMITT°EFcJT

.10’., ._

•, tJ’ —

1. THIS REGIONAL GEOLOGIC CROSS SEC11ON IS BASED ON INFORMATION FROM ON—SITEBORING LOCATIONS AND OrF—SITE PRIVATE WATER WELL LOGS. ACTUAL CONDiTIONSMAY VARY.

3. THE THICKNESS OF THE GLACIAL CLAY iLLS W,TH INTERMITTENT SAND AND SILTLENSES IS APPROXIMATELY 170 FEET THICK BELOW THE INVERT OF THE CLINTONLANDFILL NO.3. CLAY MAKES UP AT LEAST 150 FEET OF THE 170 FEET OF GLACIALCLAY TILLS WITH INTERMITTENT SAND AND SILT LENSES.

WEST

LANDFILL NO,

FILL__\\\\

3

CHEMICALWASTE UNIT

LANDFILL

I

MUNICIPAL

-J

C)F—

LU>

NO.2

SOLID WASTE

I

UNIT

I0 I

0

SAN

EAST

D AND SILT LENSES

LEAST c:AT150’ OF CLAY

4

I/

--

.,

‘I.

9,c. [srrnetd. c h repored thin doot For o wedrc po*tt orç.,rpose- &l !ttn,oti o,tched withhq this doami.,t is cnpinhted ie

renn*s .ntelectud propty or Sion En*orirn.,t. t,,c. This docornent noy nottensed or copied. is port or to, whole. For ony reosns .ithou I enpressed writtent,ne,t ty Shy,, EnrownrJol. In

NOTES

MAHOMET AQUIFER

2. THIS GEOLOGIC CROSS SECTION WAS DEVELOPED TO SHOW THE LOCATION OF THEMAHOMET AQUIFER AND ITS POSITION RELEVANT TO THE INVERT GRADES OF THECLINTON LANDFILL NO.2 AND NO.3.

... :

Clinton Landfill, Inc. aShaw®Shaw Environmental, Inc.

CLINTON LANDFILL NO.3 CHEMICAL WASTE UNITDEWITT COUNTY, ILLINOIS

FIGURE 1REGIONAL GEOLOGIC CROSS SECTION - WEST TO EAST

DESCRIPTION DRAWN BY: APDI APPROVED BY: DJDI PROJ. NO.: 1260171 DATE: AUGUST 2010

60’ -

-J

C)I

Lii>

NOTESTHIS REGIONAL GEOLOGIC CROSS SECTiON IS BASED ONINFORMATION FROM ON—SITE BORING LOCATIONS. ACTUALCONDITIONS MAY VARY.

2. THIS GEOLOGIC CROSS SECTION WAS DEVELOPED TO SHOWTHE LOCATION OF THE MAHOMET AQUIFER AND ITSPOSITION RELEVANT TO THE NVERT GRADES OF THECUNTON LANDFILL NO.3,

3. THE THICKNESS OF THE GLACIAL CLAY TILLS WiTHINTERMITTENT SAND AND SILT LENSES IS APPROXIMATELY170 FEET THICK BELOW THE INVERT OF THE CLINTONLANDFILL NO.3. CLAY MAKES UP AT LEAST 150 FEET OFTHE 170 FEET OF GLACIAL CLAY TILLS WiTH INTERMITTENTSAND AND SILT LENSES.

NORTH SOUTH

I

III0 —

0 600’

HORIZONTAL

In0

NN

0

a00

I(N

CLINTON LANDIFILL NO.3 CHEMICAL WASTE UNIT

ADEWITT COUNTY, ILLINOIS

t’tI Clinton Landfill, Inc. FIGURE 2

ShaW®Shaw Environmental, Inc. REGIONAL GEOLOGIC CROSS SECTION - NORTH TO SOUTH

DESCRIPTION DRAWN BY: BWNI APPROVED BY: DAMI PROJ. NO.: 1280171 DATE: AUGUST 2010

IzDLUIa)a)

-Jo

LU

-:IC.)

Oo

Zc.)

-J-JIi-—Cz0Iz-JC)

>I-.a,zuJU

,

Co

lii

z

0<zD0(30ciCC

u.4-J

Cci2C2>CwCu

-cC’)

DEC

REA

SING

POTEN

TIAL

FOR

CO

NTA

MIN

ATIO

N

iumiiuiiuuiiuuuuun

00c’s

Li,

0C-,

0Ld

0N00z00-

000CLii

>00-

0.

Ca034C

OM

pX;IA

J;!suasJa

J!nbt

c;u

no

;;!M

arg

aJnB

!J\a

suO

dsaJ

d3srfs

aJnB

!J\v

d]s

n6M

p\jT

o82T

\s1zaro

Jd\a

v3opvs

Nd

1T

zcb

OrQ

Vgdg

‘OM

PA1

4S

UiS

JOj!flbCAILnOD

D,!M

acaaJ.vadn£

aJfl6!dWC

11OdsaJ

Yd]5

If$JflO

!lVd9S

fl\bM

p\t1

OS

Z1\S

3[O

id\av

303,It1

Cl)

ISD

Nd

£UO

C2

6O

O2

/2/

ATTACHMENT I

Hackley, Panno, and AndersonJulylAugust 2010

Chemical and isotopic indicators of groundwater evolution in the basal

sands of a buried bedrock valley in the midwestern United States:

Implications for recharge, rock-water interactions, and mixing

Keith C. Hackley”, Samuel V. Pann&, and Thomas F. Anderson2

1llinois Stole Geological Survey, Institute ofNatural Resource Susra inabilir’y. University ofIllinois, 615 E. Peabody Dr. Champaign,

illinois 61820, USA2Deparrment of Geology (emeritus), 1301 W. Green St., Urbana, illinois 61801, USA

ABSThCF

Buried bedrock valley aquifers can be

found throuØ!qanada and the northern

United States where glacial deposits have

filled in previously exposed bedrock valleys.

The Mahomet bedrock valley is an cost-west—

trending buried valley in central Illinois conisining basal Pleistocene sands and gravels

making up the Mahowet aquifer and the

contemporaneous Sankoty Mahomet quifer,

which are the major sources of freshwater

for east-central Illinois. The hydmcheniical

• characteristics of the Mahotnet and Sankoty

Mahomet aquifen change sigidllcantly

acro the buried bedrock valley. To deter

mine the geocharical pen co.t’othng

• the chemistry of the water, possible ground

water enhing, and the regions of major recharge, over SO samples from the Mahontet

aquiferi the Sankoty Mahomet aquifer, and

slower aquifers were analyzed for their

chemical and isotopic composition, including31:0,80, onC, fl TMC, and ‘H.

Four geochemical regions were observed

an the aquifers. The central and astern

region of the Mahomet aquifer had dilute

chemistry and medium ‘4C activities, sag

gesting relatively recent recharge fnnn the

stnlaca The northeastern Mabomet aquifer

region had variabfr sara and 8’S values,

medium chloride concentrations, and low

“C acGvit suggesting arising with bedrock

vrom1dwafrr alan with snflte red.4vwThe western Mahomet aquifer region had the

highest chloride, dissolved — carbon,

and methane concentrations and showed a

continuous decrease in ‘C activity, suggest

ing seepage from bedrock units, strong re

ducing conditions, and isolation from surfi

‘E-mthl: hacklcy@isgsjiiucs4u

cial rechg Characteristics of the SankotyM.ahosnet aquifer indicated rapid freshwater

recharge and mixing with western Mahomet

aquifer water.The U) and 80 values indicated little to

no Pleistocene water in the Mahomet bedrock

valley aquifer system, suggesting an age limit

of ca. 11,000 yr n.E for most of the ground

water. The tritium data indicated modern re

charge in some shallower aquifers, but little

to none in the Mahoinet aquifer and Sankoty

Mahomet aquifer, except near a river where

stacked sands may have created a hydrologic

window to the Mahomct aquifer. It appears

that most o(the Mahoinet aquifer is well pro

tected from surficial contamination. The ap

proacb aced in this study enabled as to better

understand and identify the processes that

control the groundwater chemistry within

the buried Pliestocene aquifer in central

IUin; processes that may be prevalent in

other buried bedrock valley aquifers distrib

uted thronajiout much of North America.

INTRODUCTION

Groundwater is an impottant source of

freshwater for much of the population in the

United States, making up 22% of all freshwater

withdrawals (Solley et at, 1998). As population and industry continue to expand across

the county, the availability of groundwater re

sources becomes a more critical issue. In some

parts of the country, such as the high plains,

groundwater is the major source of freshwater,

and usage is ourpacing recharge (Alley et at,

1999). Maintenance of water quality in potable

aquifers is another concern. For example, in

the midwestern United States, the quality of

water in some of the shallower aquifers has

been degraded due to infiltration of agricul

tural chemicals (USGS, 1999a). In addition,

road deicers in the north-central and northeast

ern United States are contaminating shallow

aquifers (Pilon and Howard, 1987; Kelly and

Wilson, 2003)Approximately 21% of the people in Illinois

rely on groundwater as their primary source

of drinking water (USGS, 19995). Like most

of the midwestern states, Illinois has ahun

darn groundwater resources located within

both bedrock units and shallower tmlithified

glacial deposits. A few of the glacial aquifers

art major freshwater resources for numerous

municipalities. This investigation focused on

the Mahomet aquifer (MA) and the Sankoty

Mahornet aquifer, which are contemporaneous

Pleistocene-age unlithifled sands and gravels

filling ancient bedrock valleys in east-central

illinois. The Mahomet aquifer is an east-west—

trending aquifer deposited in the Mahomet

bedrock valley. The Maboniet aquifer extends

from western Indiana to central Ulinois, where

it intersects the north-south--trending Sankoty

Mahomet aquifer in the Mackinaw bedrock

valley (Fig. I). The Mahomet aquifer and the

Sankoty Mahomet aquiW have been supply

ing high-quality freshwater to municipalities,

industries, homeowners, and farmers for more

than four decades. Over the last two decades,

the use of, and interest in, the Mahomet and

Sankoty Mahomet aquifers has increased due

to expanding population and industry in east-

central Illinois, as well as depletion of sur

rounding conuminifles’ surface-water reservoirs

during periods of drought (Illinois State Water

Plan Task Force. 1997). The increase in with

drawal and potential future use of these aquifers

have raised questions concerning the quality

and quantity of water in the aquifers and their

future integrity.Although the geology and hydrogeology of

the buried Mahomet bedrock valley have been

the subject of several previous studies over the

GSA BuItedn;JulytAugust 20l0;v. (22; no. 71S;p. 1047—1066; dci: ID.! 130/B26574J; 17 figures; Data Repository item 2009286.

Pa pcrmssioo to con, cuouci ediling@geosocieiycrg

02010 (5eOJOgicaI Society of Ame,ica

11

1047

IM

acki

naw

Bed

rock

Val

leyl

5W

este

rnM

A

C 8 0 &o a ‘F)

Ct ‘< 0 i I ‘ o tQ C C

Con

flue

nce

Are

a

t4

Itu

dyA

rea

PE

OIA

C0

DC

—

FUL

TO

NC

O.‘

——

—V

46

?Ø

aloom

lagto

&—

ica

•$2

4N

orm

al

-H

a‘r

j6t

3t

1ME

NA

RO

Q(

Ikic

oIn

CM

___

I—

si

2I

TII

N_

__

j_

___J.

100

150

IOW

RIW

Flaw

RZW

P6W

P5W

P4W

P3W

LJ

N

Cen

tral

MA

Nor

thea

ster

nM

AE

aste

rnM

AO

nar

ga

Val

ley)

4r5

nrN

T27N

’jflfl

.1-P

016*

6IR

OII

C

•

MOS

S

T2

Z&

________

‘,$$i_j

jT

1IN

121N

S

P11

W

Div

isio

nsfo

rre

gion

sof

MA

IN

T8

0

K

CIIM

SSA

•

S 2 I I 2 0 I,

Pot

enti

omet

ric

cont

our

iine

s*:s

s Bed

rock

high

4Al

OE

\ RIC

E

04

81216

2OM

Hea

LZ

LE

JZ

.11

1D

Con

tour

Inte

rval

lOft

(infe

etab

ove

mea

nse

aie

vel)

PIE

qIE

PIE

Wei

ian

dID

——

Gro

undw

ater

divi

de

Fig

ure

4.M

apsh

o’i*

ing

the

locatI

ot

the

wel

lssa

mp

led

fl-am

the

Mah

omet

bed

rock

valle

yaq

uife

rsy

stem

. The

cont

ours

are

the

pote

ntlo

met

ric

surf

ace

for

the

basa

lM

ahrn

flet

aqui

fer

(MA

)(W

ilson

etal

.,19

98).

The

illi

nois

plan

eco

ordi

nate

syst

em(d

ivid

edby

1000

)Is

show

n

atso

uth

ernm

ost

tow

nsh

iplin

es. M

ajor

reg

ion

sar

ese

par

ated

bysh

aded

lin

ean

dla

bele

dac

ross

the

top

ofth

ed

iag

ram

,C

ross

-sec

tion

line

s

B.B

C-B

’,an

dV

-B’

are

also

incl

uded

.

Chemical and isotopic indicators ofgroundwater evolution

-‘

04302

01J

70- -A

60- -

C)2aC)

50-

40-

30- -

20- -

10- -

A SMA-co4,fluence

A Glasford-coottuence

A

AAAA

A

A

A

A

A A

I • I .

04303

Methane (moLt)

rock land surface. The 3D and 8O values formost of the groundwater in the Mahomet aquifer and the shallower Glasfoni sands are quitesimilar to present-day precipitation. These dataindicate that there is little to no Pleistocenewater remaining in the aquifer system, puttingan upper age limit for most of the groundwaterat the start oldie Holocene, ca II.) yr B.RThe tritium results indicate that there is modernrecharge into the Wedron sands and some of theGlasfoni sands, but very little modern water occurs in the basal sand of the Mahomet bedrockvalley. Of the sites sampled, only one area inthe Mahomet aquifer near wheat the SangamonRiver crosses the bedrock valley had detectibletritium. These tritium data we consistent withrecent seismic and monitoring well drawdownstudies by the 1505 and ISWS that have staggested a hydraulic window where groundwaterdischarges to the Sangarnon River when thetires is low and groundwater rechnges duringperiods of high stage or excessive groundwaterpumping (Roadcap and Wilson, 2001).

The central-eastern region of the Mahornet— aquifer contained the highest “C activity and04304 most dilute groundwater compared to the rest

of the Mahomet aquifer, indicating that thegroundwater in this region has gone throughtire least water-rock interaction. These isotopicand gc&hemica! characteristics imply that thisregion is the area of most rapid recharge formost of the Mahomet aquifer, as proposed byPanno et al. (1994). The very low C1 concert-trations in the central Mahomet aquifer regionsuggest that high volumes of freshwater (glacialmeltwaten) probably flushed the stacked sanddeposits and leached the more soluble mineralsso that the present-day groundwater has relatively low dissolved solids concentration.

—‘Tca&inicai and isotopic results for theMahomet aquifeflcjvestem and northeastern (Onarga Vale) legions indicate that theseareas of the aquifer are relatively isolated fromsurficial recharge and have been significantlyinfluenced by the infiltration of older (low t4Cactivity) groundwater from bedrock units withereater dissolved inn concentrations. The en-.

concentration in the confluence region; r’ for the

0 04301

Figure 14. Comparison of “C and CH4Sankoty Mahoruet aquifer data is 0.9.

activities observed in groundwater from samplesof the Mahomet aquifer and the Glasfont Sandin the northeastern part of the Mahomet bedrockvalley indicate a mixture of deeper upwellinggroundwater and shallow infiltrating groundwater plus sulfate reduction occurring in parts ofthe northeastern region of the Mahomet bedrockvalley. The mixture of groundwater from bedrock units in the northeastern region appears toextend into northern Vermillion County. The increased CP concentrations and continuous dropin “C activities observed for the western part ofthe Mahomet aquifer (fig. 15) suggest there hasbeen greater isolation from surilcial rechargeand seepage from bedrock units mixing withthe Mahomet aquifer groundwater flowing fromthe central region westward. The cross sectionsthat cut the Mabomet bedrock valley diagonally(Figs. 13 and 16—Il) show the relationshipsamong the shallower aquifers, the deep basalsand aquifer and the sides of the bedrock valleyfrom where the lithology of the bedrock changesabruptly near the Piatt-Champaign County lineto where the bedrock is primarily carbonate inChampaign County. Chloride concentrationsand “C activities are included on the cross sections. The jesuits show an increase in 0 anddecrease in “C activity near the sides of the val

ley. especially close to the Pennsylvanian-agebedrock on the western side of tire aquifer (seeFig. 3 for bedrock lithotogy). This emphasizes the relationship of the Pennsylvanian-agebedrock to the seepage of older mote salinegroundwater into the western Mthomet aquifercompared to the carbonate bedrock in the cen

______________________

tral portion of the Mahomet aquifetAs the groundwater from the Mahomet aqui

fer flows into the Sankoty Mahomet aquifer; thechemical composition and “C activity changedramatically. In this confluence a the geochemical nnka.p of the groundwater of thebasal Pleistocene sands and gravels is stronglyinfluenced by a combination of relatively rapid

_________________________________

recharge of younger, more dilute water inflltrat- ‘tnent of S0; Ca2’, Mgi’, Na afl5äing from the surface and the microbial processes S& in the Onarga Valley is probably the result ofassociated with methanogenesis. water-rock ‘mteraclious with bedrock lithology,

including Silurian, Devonian, and Mississippian carbonates and Pennsylvanian cyclotherntype deposits (stales, coals, and argillaceouslinrestones and sandstones). The PS and 8°Cvalues as well as the SO and NC concentrations in and around the Onaiga ‘Valley regionsuggest that groundwater upwelling throughbedrock units is dissolving secondary gypsum,precipitating calcite, and mixing with freshergroundwater in the Mahomet and Glasfoni

SUMMARY AND CONCLUSEONS

The chemical and isotopic characteristics ofthe groundwater in the aquifers of the Mahometbedrock valley and adjacent confluence areahave revealed many important aspects of thegroundwater evolution in aquifers that havebeen created from glacial deposits filling in thetopographic undulations of the previous bed-

Geological Society of America Bulletin, July/August 2010 1061


Figure 16. Crass section (C-fr)of the Mahomet bedrock valleyinducting “C, I501, and (CIIdata for several wells (modifiedfrom Hackley, 2002). Note thelower “C activities and higherCt concentrations near thewestern side of tbe valley,where the bedrock is composedof Pennsylvanian deposits.MSIr-mean sea leveL

® =‘4c(pMC)= SO (mgL)= ci- (mg.’t)

$

Vosbcai exaggeration =425x

sands. The isotopic data also indicate that SO Na’) are primarily explained by the influx ofreduction and oxidation of organic carbon occur saline groundwater horn the &nnsylvanian-ageas the groundwater moves up into the Mahotnet bedrock (Panno a at l99X Methane producaquifer and shallower sands. evidence of mix- Lion is undoubtedly a consequence of stronglog between infiltrating groundwater hum bed- reducing conditions in this part of the aquifer.rock in the Onarga Valley and groundwater from The relatively high DCC concentrations in thethe Mahomet and Glasford sands extends into western Mahomet aquifer could also be associnorthern Vermilion County. The low TMC activi- ated with the influx ofdeeper groundwater fromties observed in this asea are due to the influx the Pennsylvanian-age bedrock units or perhapsof older groundwater from bedrock units, dis- leaching of organic matter in clastics from thesesolution of carbonates, and oxidation of organic bedrock units anWor diffusion from organic richjfl3fljlv IOSQ2-AIICiOn__ _Plieistocene deposits. The progressive decreaseThe western region of the Mabomet aquifer in “C. activity is probably a consequence ofis characterized by higher concentrations of several processes: infiltration of older ground* CH4, DOC C Na’, and 11CC);, greater 6°C water from bedrock units, methanogenesis, andvalues, and a progressive decrease in ac- the dissolution of carbonates in the aquifet astivities to the west The isotopic data support well as radioactive decay as the water slowlythe hypothesis that the higher concentrations migrates westward. The progressive decrease inof chemical constituents (especially Ct and “C and the lack of significant shallow sand de

posits above the Mahotnet nifer in the ustnnregion imply that this area is fairly isolated froms_—

confluence area where the Mahometaquifer and Sankoty Mahomet aquifer meetshows large variations in 14(2 activity and chemical constituents, including Cl concentrations.This nan is significantly influenced by a combination of groundwater mixing between relatively dilute infiltrating surficial water that hashigh “Cactivities and low Cr concentrationswith older groundwater emerging from thebasal sands of the Mahomet aquifer containing a greater amount of dissolved constituentsand the microbial processes associated withmethanogenesis.

The isotopic and chemical characteristics ofgroundwater in the basal sands of the Maboinetand Mackinaw bedrock valleys indicate that

C

w r‘0”,

06

B,

-J0)2S

0SC0

0us

(It) (m)

750 - 230

700- -215

65 200

600-185

55oI0

-1555O

-140450-

-125a

-110350

-95

ThicAPennsylvanian

j ThthF—

deposils

bedrock

5 0I I I

5 0 5

10 15 20m1

15 25 30km

Geological Society of America Bulletin, JulyiAugust 2010 1063

Chemical and isotopic indicators of groundwater evolution in the basalsands of a buried bedrock valley in the midwestern United States:

Implications for recharge, rock-water interactions, and mixing

Keith C. HackleyU, Samuel V. Panno’, and Thomas F. Anderson2‘Illinois Stare Geological Survey, Instilute ofNatural Resource Sustainability, University ofIllinois, 615 H. Peabody Dr. Champaign,Illinois 61820, USA2flepartmenr of Geology (emeritus), 1301 W Green St., Urbana, Illinois 61801, USA

ABSTRACT

Buried bedrock valley aquifers can befound throughout Canada and the northernUnited States when glacial deposits havefilled in previously exposed bedrock valleys.The Mahontet bedrock valley is an east-west-trending buried valley in central Illinois contaming basal Pleistocene sands and gravelsmaking up the Mahomet aquifer and thecontemporaneous Sankoty Mahomet aquifer,which are the major sources of freshwaterfor east-central Illinois. The hydrochemical

1’ characteri tics of the Mahomet and SankotyMahomet aquifers change significantlyacre the buried bedrock valley. To determine the geochemical procees controllingthe chemistry of the water, possible groundwater mixing, and the regions of major re-charge, over SO samples front the Mahornetaquifer the Sankoty Mabomet aquifer, andshallower aquifers were analyzed for theirchemical and isotopic composition, includingW’O, 81), 8°C, 8_S. “C, and ‘H.

Four geochemical regions were observedacrt the aquifers. The central and easternregion of the Mahomet aquifer had dilutechemistry and medium “C activities, suggesting relatively recent recharge from thesurface. The northeastern Mahomet aquiferregion had variable sulfate and 8_S values,medium chloride concentrations, and low‘4C activity. suggesting mixing with bedrockgroundwater along with sulbte reduction.The western Mahomet aquifer region had thehighest chloride, dissolved organic carbon,and methane concentrations and showed acontinuous decrease in “C activity, suggesting seepage from bedrock units, strong reducing conditions, and isolation from surfi

‘B—mail: hackley@isg&uiuc.edu

dat recharge. Characteristics of the SankotyMahomet aqnifer indicated rapid freshwaterrecharge and mixing with western Mahometaquifer water.

The &) and 8”O values indicated little tono Pleistocene water in the Mahornet bedrockvalley aquifer system, suggesting an age limitof ca. 11,000 yr BSt for most of the groundwater. The tritium data indicated modern recharge in some shallower aquifers, but littleto none in the Mahomet aquifer and SankotyMahomet aquifer, except near a river wherestacked sands may have created a hydrologicwindow to the Mahomet aqnifec It appearsthat most of the Mahotnet aquifer is well protected from surficial contamination. The np-preach used in this study enabled us to betterunderstand and identify the processes thatcontrol the groundwater chemistry withinthe buried Ptiestocene aquifer in centralillinois; proces that may be prevalent inother buried bedrock valley aquifers distributed throughout much of North America

INTRODUCHON

Groundwater is an important source offreshwater for much of the population in theUntied States, making up 22% of all freshwaterwithdrawals (Solley et aL, 1998). As population and industry continue to expand acrossthe countiy the availability of groundwater resources becomes a more critical issue. In someparts of the country, such as the high plains,groundwater is the major source of freshwater,and usage is outpacing recharge (Alley et at.,1999). Maintenance of water quality in potableaquifers is another concern. For example, inthe midwestern United States, the quality ofwater in some of the shallower aquifers hasbeen degraded due to infiltration of agricultural chemicals (USGS, 1999a). In addition,

road deicers in the north-central and northeastern United States are contaminating shallowaquifers (Pilon and Howard, 1987; Kelly andWilson, 2003).

Approximately 21% of the people in Illinoisrely on groundwater as their prixnaiy sourceof drinking waler (USGS, 199%). Like mostof the midwestern states, illinois has shun-dent groundwater resources located withinboth bedrock units and shallower unlithifiedglacial deposits. A few of the glacial aquifersare major freshwater resources for numerousmunicipalities. This investigation focused onthe Mahomet aquifer (MA) and the SankotyMahomet aquifer, which are contemporaneousPleistocene-age unlithified sands and gravelsfilling ancient bedrock valleys in east-centralIllinois. The Mahomet aquifer is an east-west--trending aquifer deposited in the Mahometbedrock valley. The Mahomet aquifer extendsfrom western Indiana to central Illinois, whereit intersects the north-south--trending SankotyMahomet aquifer in the Mackinaw bedrockvalley (P1g. 1). The Mahomet aquifer and theSankoty Mahornet aquifer have been supplying high-quality freshwater to municipalities.industries, homeowners, and farmers for morethan four decades. Over the last two decades,the use of, and interest in, the Mahomet andSankoty Mahomet aquifers bits increased dueto expanding population and industry in east-central Illinois, as well as depletion of surrounding communities’ surface-water reservoirsduring periods of drought (Illinois State WaterPlan Task Force, 1997). The increase in withdrawal and potential firture use of these aquifershave raised questions concerning the qualityand quantity of water in the aquifers and theirfuture integrity.

Although the geology and hydrogeology ofthe buried Mahomet bedrock valley have beenthe subject of several previous studies over the

GSA Bulletin; July/August 2010; v. 122; no. 7/8; p. l047—1066;doi: 10.1130/826574.1; 17 figures; DataRepositoryitem 2009286.

Fe, permission to copy. contact [email protected] 2OIOGeoIogicaI Society of America

1047

Hackiey et aL

FIgure 1. Isopach map of theMahomet sand in the Mahoinetbedrock valley (Mliv) as defined by the 500 ft elevation contour (modified from Kemptonet al., 1991). MSL.—mean sealevel.

IZ]< 100 It or 30-Smthss

> lOOftor 30.5 m siltfacies —sco-. 500 ft or 152 m bedrockthickness elevation above MSL

past 60 yr (Horberg, 1945; Stephenson, 1967;Visocky and SCMCJIt, 1969; Kempton ci aL,

1982,1991; Wilson ci aL, 1998). the geocheniical reactions that control the chemistry of thegroundwater, the major areas of recharge, andthe age of the groundwater have only begun tobe studied (Panno ci aL, 1994; HackIe’, 2002).

Arsenic is also a concern for some parts of the

Mahonn aquifrr and shallower units (Warner,2001; Warner ci a, 2003; Kirk ci aL. 2004;Kelly. 2005).

To help improve our understanding of thegeochemical characteristics of the groundwaterin central Illinois, we conducted a geochemical study of the Mahomet aquifer and SankotyMahomet aquifer systems using both chemicaland isotopic analyses of the water and many ofits dissolved constituents. The major objectives

of this investigation were to: (1) determine thegeochemical reactions controlling the chemical and isotopic composition of groundwaterwithin the aquifers, and (2) identify the majorareas of recharge.

Chemical and isotopic variations observed

in the groundwater within the Mahornet andSankoty Mainnet aquifers and their bound

ing aquifers have been used to help define thegeochemical evolution, including microbialprocesses and possible mixing of differentgroundwater sojuces. Indicators of biogeochemical reactions within the boded aquifers change

along the groundwater flow path from areaswhere there is little obvious microbial influence to areas where there is significant microbial influence, including sulfate reduction andmethatiogenesis. The redox conditions that areassociated with changes in sulfate and methaneconceatnijoas ate reflected in other parametersas well, such as the bicarbonate concentrationand the stable carbon isotope values of dissolvedinorganic carbon. For example, sulfate ruhadionin groundwater is usually coupled with oxidation of organic matter, which typically leads toinert negative carbon-13 isotopic compositionsand poàive sulfur-34 isotopic ctwqxskknt (kithe other hand, groundwater with substantialmicrobial methane generation typically containsvery little to no sulfate and exhibits more positive carbon-l3 isotopic compositions. Changesin carbou-13, carbon-l4, and chloride concentrations across the Mahomet and Sankoty Mahornetaquifers reflect different degrees of water-rockinteraction, biogeochemical reactions, as wellas influxes of younger and fresher water fromabove or older, more saline groundwater humunderlying bedrock. A combination of the chemical and isotopic data for both the inorganic andorganic components of the groundwater allowsus to create a rifle complete understanding ofthe reactions that control the hulk chemistry andhelps to delineate locations where the groundwater is receiving significant recharge.

Geological Setting and Background

The Mahomet aquifer is a major aquifer madeup of sands and gravels originating from glacialoutwash deposited by Pleistocene continentalglaciers in an extensive bedrock valley in east- -

central Illinois. The Mahornet aquifer was onceconsidered part of the larger “Mahomet-Teays”buried drainage system, which was believedto extend eastward into Virginia. However, asdiscussed by Melhorn and Kempton (1991),studies have indicated that the Teays drainagesystem was not a single cthesive drainage systea The Mahornet aquifer is just one of manybusied bedrock valley aquifers that exist acrsmuch of the Midwest, not to mention the northern United States and parts ofCanada (NRCAN,2008; Warner and Arnold, 2005; Shaver andPose, 2005; Bleueret aL, 1991).

A number of studies have examined the physical nature ofthe Mahomet aquifer, delineating thebasic shape, size, and stratigraphy of the depositswithin the bedrock valley, as well as the geologyand hydrogeology of the aquifer (Horberg, 1945,1953; Stephenson, 1967; Visocky and Schicbt,1969; Kemptonetai. 1982,1991). Whenusingthe 153 in (500 ft) bedrock elevation contour todefine its boundaries, the Mahomet bedrock valley in Illinois is over 200 km (124 ml) long andranges from —13 km (8 mi) wide at the illinois-Indiana border to —32 km (20 mi) at its widest

•Tusccda

1048 Geological Society of America Bulletin, JulyIAugust 2010

Chemical and isotopic indicazon ofgroundwater evolution

points. The Mahomet aquifer begins in westernIndiana and extends to central illinois, whereit intersects, in a large confluence area, withthe north-south—trending Sankoty Mahornetaquifer in the Mackinaw bedrock valley. TheMackinaw bedrock valley is filled with sandsand gravels of the Sankoty Sand Member of theBanner Formation, which make up the SankotyMahomet aquifer and are contemporaneous withthe sands and gravels of the Mahomet aquifer(Ketnptonetal., 1991).

‘The sand and gravel that constitute theMahomet aquifer and occupy the basal parts ofthe buried Mahomet bedrock valley alt knownas the Mahomet Sand Member of the BannerFormation and are generally greater than 30 mthick (Fig 1). The Banner Formation is estimated to have formed molt than 400,X) yr ago(Grimley, 1996) and is regarded as pre-l]]inoisanin age (Willman et at., 1975; Hansel andJohnson, 1996). The Mahomet Sand Memberis overlain by tills of the Banner, Glasford, andWedron Formations (Fig. 2). The three majorformations are typically separated by weatheredzones, in some cases, with substantial soil developinent, periodically enriched with organicmatter, and, in some places, pent deposits. Mostof the Glasfoni Formation is of fflinoian age(mote than l50ft) yr old) (Grimley, 1996)and contains locally important sand and gravellayers and lenses interralated with the till. Thesesands and gravels are referred to as the GlasfordSand, and they form a significant aquifer insome parts of the Mahomet bedrock valley. TheGlasford Formation is overlain by ‘WisconsinanStage deposits, including the Robein Silt HenryFormation, and the Wedron Formation (Pig. 2).Both the Wedron and Henry Formations containrelatively small sand and gravel outwash de— that axe thinner and moth more limitedin scope than either the Mrixrmet aquifer orGlasford Sand. The Robein Silt contains a largeamount of organic matter, including wood flagments, peat deposits, and an organic-rich paleosot known as the Farindale Geosol (Cwiy andFoilmer, 1992).

The bedrock exposed in the floor and wallsof the Mahomet bedrock valley includes rocksof the Silurian, Devonian, Mississippian. andPennsylvanian systems (Fig. 3) (Kempton et a!.,1991). Very few wells in the Mahomet bedrockvalley area are screened in the bedrock units because of their low yields and increasing salinity with increasing depth (Visocky and Scbicbt,1969). The western portions of the Mahomet andthe Mackinaw bedrock valleys are cut predotninantly through Pennsylvanian rocks consistingmostly of shale interbedded with thin lime-stones, sandstones, and coal seams. The Pennsylvanian rocks generally have low permeability

and axe not an important aquifer in this area(Visocky and Scbicht, 1969), However, beyondthe bedrock nlle in the bedrock upland areaswhere the glacial deposits generally are thin andlack significant sands and gravels, the Pennsylvanian rocks aze used to supply water for farmsand small municipalities (Csallany, 1966). Wellsdeveloped in the Pennsylvanian units seldompenetralernorethan200or300ft(til or9l m)and usually are screened in the thin limestonesand sandstones (Csaliany. l966 The centraland eastern portions of the valley expose rocksof the Mississippian. Devonian, and Siluriansystems and some of the Pennsylvanian systent The Mississippian, Middle Devonian, andSilurian rocks are predominantly limestone anddolomite, but very few wells in east-centralillinois are developed in these carbonate units(Csallany and Walton, 1963). The Mississippianlimestones generally have low permeability andonly yield small supplies of water where the rockis fractured arid creviced (Csallany and Walton,1963). The Upper Devonian strata are primarilyshale. The Middle Devonian limestone is rarelyused as a sour of water due to the paucity ofsecondary permeability and associated sohrtion opening& The water-yielding propertiesof the Silurian carbonates are highly variable.The greatest yields are obtained in areas where

the Silurian carbonate rock is near the bedrocksurface and the top of the limestone or dolomiteis weathered and contains crevices and dissolution features (Csallany and Walton, 1963). Ineast-central illinois, wells producing groundwater from the Silurian carbonate bedrock areprimarily in northern Font county and IroquoisCounties (Woller, 1975; Harridan, 1970).

Hydrologic characteristics of the Mthometaquifer and the Glasford awifrr were originally described in Visocky and Schidt (1969).Gilt (1970), Sandetson (1971), and Kernptonet a!. (1982), and summarized in Kempton ct at.(1991). The hydrologic characteristics of theSanicoty Mahomet aquifer sands were describedin Wilson et al. (1998). According to Kemptoneta!. (1991), the hydraulic conductivities for theMahometaquiferand the Glasfonl Sand average-13 x 10 mis and 4 x 10” mis, respectively.The hydraulic conductivities measured for theSankoty Mahomet aquifer and Glasford Sandin the Mackinaw bedrock valley average 9.7 xl0’ mis and 16 x 10” mis, respectively. Theconfining glacial-till layers have average verticalconductivities ranging from -8.8 x 10° mis to2 x lO’ mis (Wilsonetal.. 1998; Keinponetal..1991). The hydraulic gradient for most of theMahornet aquifer is -0.19 mflcm, except near thecone of depression that has recently developed

FIgure 2. Schematic diagram showing relative stntigrapldc relationships between Pleistocene and bedrock formations (modified front Kempton et a, 1991).

Geological Society of America Bulletin, JulylAugust 2010 1049

Ifackley a aL

FIgure 3. Bedrock geology forthe area of east-central illinois containing the Mahometaquifer. The Mahomet bedrock valley is outlined relativeto the 500 ft elevation contour(modified from Kempton eta!.,1991; Kolata et a!., 2005).

near the cities of Champaign-Urbana (Hg. 4).There is a substantial gradient change in the confluence area where the gradient increases from—022 rn/km in the western Mahomet aquifer to038 rn/kin in the middle of Tazewell County(Wilson a a!., 1998). The potentiornetric healsin the confluence area indicate there is a groundwater divide that gradually deflects the flow ofgroundwater from the Mahomet aquifer to thenorth and to the south as it enters the confluenceregion (FIg. 4). The potentiometric head of theGlasford Sand aquifer is —15-9 m above that ofthe Mahomet aquifer, but the Glasford Sand istypically separated from the Mahornet aquiferby —15-30 m of confining glacial tilL Historicalrecords indicate the highest hydraulic heads for

re Mahomet aquifer were located in northernChampaign, southern Ford, and northwestern

Vermilion Counties (Keinpton et a, 1991). Inthe northeastern portion of the Mahornet aquifet known as the Onarga Valley, hydraulic headdata indicate that groundwater gradients alereversed (Hamdan, 1970). Groundwater mayoriginate from surrounding uplands, percolatedown into the bedrock valley, and recharge theMahomet aquifer and up into the Glasfoni Aquifer in the central portion of the Onaiga Valley(Hanidan, 1970).

Hydrochemically, three water types havebeen identified in the Mahomet aquifer (Pannoa aL, 1994). Groundwater in the central portion of the aquifer is a dilute-type water characterized by Ct, Mg2’, and HCO;. OnargaValley groundwater has more total dissolvedsolids (ItS) and is characterized by Ca2’, Mg2,HCO;. and SO Groundwater in the western

portion of the Mahomet aquifer is characterizedby Ct, Mg2. and HCO with relatively largeconcentrations of Na’ and Cl-. The greater Cland Na’ concentrations were interpreted to bethe result of groundwater upwelling from bedrock near the edge of the Charleston Monocline(part of the La Salle anticlinorium), which runsapproximately perpendicular to the trend of theburied bedrock valley near the border of Planand Champaign Counties (Fig. 3).

SAMPLING AND ANALYTICALMETHODS

This paper includes the analytical resultsfrom 86 groundwater samples collected fromthroughout the Mahomet bedrock valley andmuch of the Mackinaw bedrock valley (Fig. 4).

Pennsylvanian System

0 10 2OrrgI I I

o to 20 3Olau

Mattoon Fm

— Bond Fm

—— Carbondale Fm

Tradewater Fm

. 500 foot elevationcontour

Tuscota anticline

Mississippian System

Bordon siltstone (includes Chouteau Is. in east-central IL)

Meppen L.a. Fren Glen Fnt, Burlington-Keokuk La

Devonlan System

NewAlbany Shale

Muscatatuck Group

Silurlan System

Siludan System (undtferentiated)

Osman/Ohartestonmonodine

1050 Geological Society of America Bulletin, July/August 2010

MA

A-’ 3 I C’,

Ct C n C C, S. C

Mac

kina

wB

edro

ckV

aile

y/W

este

rnM

AC

entr

alM

AN

orth

east

ern

MA

Eas

tern

_C

onfi

u.n

ceA

rea

(Ona

rga

Val

ley)

It’

A[IR

Oo&

Tfl

:

__

__

__

I5.

JJ%.

.N

.I

j.•

-S-—

——

44r9

Rofle

(uw

n*\

CJA

OIS

C

Peta

r:‘

)Itud

yA

rea

IiL

._

__

IT

5T

\flJ

‘Ne1

30

012

4Niq

due

V

n

_____

______

floW

flgW

fIW

flT

Wfe

WA

$WR

4WR

3WR

aw1

WfI

E‘

.110

48

1218

2OM

ilea

iiPL

AvI

CO

AII

WR

nC

onto

urIn

terv

allO

ft

Divisions

for

Pot

enti

omet

ric

Bed

rock

high

(in

feet

abov

em

ean

sea

leve

l)

eg

lon.

ofM

A—

con

tou

rli

nes

CH

MPU

Well

and

ID—

—G

roun

dwat

erdi

vide

Figu

re4.

Map

show

ing

the

loca

tion

ofth

ew

ells

sam

pled

from

the

Mah

omet

bedr

ock

valle

yaq

uife

rsy

stem

.The

cont

ours

are

the

pote

ntio

.

met

ric

surf

ace

for

the

basa

lM

ahom

etaq

uife

r(M

A)

(Wils

onet

at,

1998

).T

heill

inoi

spl

ane

coor

dina

tesy

stem

(div

ided

by10

00)

issh

own

atso

uthe

rnm

ost

tow

nshi

plin

es. M

ajor

regi

ons

are

sepa

rate

dby

shad

edlin

ean

dla

bele

dac

ross

the

top

ofth

edi

agra

m.

Cro

ss-s

ectio

nlin

es

B-B

’,C

-B’,

and

D-B

’ar

eal

soin

clud

ed.

I C, I I

HackJey et aL

Sampling sites extend from the Indiana-illinois,order westward to the central part of illinois

(Tazewell County). Most of the groundwatersamples were obtained from the basal Mahometand Sankoty Sand Members of the Banner Formation, some from the overlying, more localized. sands within the Glasford Formation, and afew from relatively shallow sands in the WedronFormation above the Glasft.rd Formation. Watersamples were collected from residential wells,monitoring wells drilled by the illinois StateWater Survey and the fflinois State Geological Survey, a few municipal water supply wellsnear Champaign-Urbana (Champaign County)and Monticello (Piatt County), illinois, and onespring in the western part of the Mahomet bedrock valley.

Sample Collection

Water samples from residential wells weltcollected from outside spigots that were notconnected to water softeners (commonly used inrural areas). Samples from municipal wells werecollected from spigots located on the dischargepipe at the wellheads. At each site a “Y” connection was fastened to the spigot, to which along hose and a short Won tube were attachedThe water was allowed to run for —20-30 mm

e through the hose and tubing while field paramw.j pn,itor. Once field parameters

stabilized, a high-capacity (145 pin filter wasattached to the short tubing and flushed with—500 mL of water prior to collecting samplesfor most chemical and — analyses.

Field parameters, including pH, lilt, specificconductanc and tempernWr were measuredfor each sampling site, The pH and specific conductance meters were automatically compensated for temperature. All the electrodes werecalibrated in the field with appropriate standards prior to sampling The techniques usedto collect the groundwater samples for chemical analyses are described by Wood (1981).Samples for cations and anion analyses werefiltered in the field through the high-capacity in-line filters and collected in 30 and 60 mE highdensity polyethylene (HDPE) bottles, respectively. The cation samples were acidified in thefield with concentrated nitric acid to a pH <2.Samples for dissolved organic carbon (DCC)analyses were collected in precleaned 250 niLamber glass bottles and preserved with (125%sulfuric acid. These water samples were placedin a cooler packed with ice for transportation tothe laboratory, where they were stored at 4°Cuntil analyzed. DCC is reported as nonvolatile

organic carbon (NVOC).Groundwater samples taken for methane gas

determination were collected in 1 gallon (4 L)

collapsible containers having caps that were fitted with plastic spigots- The containers wereevacuated in the field using a portable direct-drive pump Thirty mIs of 0.13% Zephrin chloride solution, a preservative, was added to thecontainers prior to evacuation. The collapsiblecontainers were then immediately connected tothe Viton tubing via the spigot in the cap. Untiltered water was allowed to flush the connectingtubes and spigot for several seconds to rid thesystem of air bubbles, and then the valve wasopened to collect the water sample. The samplecontainer was filled with slightly less than onegallon of water and brought back to the laboratory for processing that same aftemoon. Theselarge samples were not kept chilled.

Water samples collected for isotopic analyses were filtered in the field Samples for SDand 8O were collected in 30 mL glass amberbottles using a cap fitted with a cone-shapedplastic insert to ensure a tight seal. The 8°Csamples were collected in 125 mL HDPEbottles, and the §M5 and ‘H samples were collected in I L HDPE bottles. The samples weretransported to the laboratory in an ice-filledcooler and stored at 4°C until analyzed. Sam-pies taken for carbon-14 (“C) analysis of dissolved inorganic carbon (DIC) were collectedin collapsible five-gallon (20 L) containers.A stir bar was placed in the container; whichwas evacuated in the field prior to being filledwith water, Filtered water samples were directly passed into the evacuated container usinga thick-walled ‘gon tubing connected to thecontainer’s spigot valve. The Tygon tubing andspigot valve were purged with the formationwater through a small opening in the valve priorto filling the containec The direct connectionto the sample container minimized degassingand contact with atmospheric carbon dioxide.These samples were too large for refrigerationin the laboratory and were processed as quicklyas possible for “C analysis (within 48 h).

Those samples containing significant methane(CH4) gas were analyzed for 6°C and 3D.Samples taken for stable isotope analyses onCH4were collected in quart-size (I L) glass jarsusing the water-displacement technique as described by Meents (1960).

Analyses

The groundwater samples were analyzedchemically for mor and minor cations, anions,DCC, and CH4 concentration. Concentrationsof cations were determined by the illinoisState Water Survey (ISWS) using a Model1100 Thermo-Jarrell Ash inductively coupledargon-plasma spectrometer (ICAP). Anion concentrations were determined at the ISGS using

a Dionex 21 Ii ion chromatograph (IC), following U.S. EPA Method 300 (O’Dell et a, 1984).The DCC concentration was determined at theISWS using a Dohrmann total organic carbonanalyzer and following methods similar to thosedescribed in ASTM D-4839-58 (1994).

The concentration of dissolved C114 in thewater was determined by analyzing the composition of the gas bubble from the 4 L collapsible container and us’mg a best-fit polynomialfor CH4 solubiity data between 0 and 30°C(Dean, 1992) to calculate the concentration ofCl!4.The sample containers were brought backto the laboratory and weighed immediately. Thequantity of water was determined from the difference between the full and empty weights ofthe collapsible sample containers. By the timethe sample was returned to the laboratory, thedissolved gases had equilibrated to atmosphericpressure and come out of solution, making abubble inside the containet l’be gas was extracted from the containers that same afternoonusing an appropriate-size graduated syringe andneedle. Prior to extracting the gas, saturated sodium sulfate solution was used to fill the needleand dead space at the end of the syringe in orderto minimize air contamination of the samplesand prevent dissolution of the gas sample intothe solution while in the syringe. The gas wasextracted by pushing the needle directly throughthe plastic collapsible container and drawingthe gas bubble into the syringe. The quantityof gas extracted was measured using the graduated marks on the syringe and was injected intoa previously evacuated glass vial (V.rcutaineta)

fitted with a septum. The gas samples were thenanalyzed on a gas chromatograph (CC).

Stable isotopic analyses included 8”O andSI) of the water, 8°C of the DIC, 8’S of thedissolved SO sulfur, and 6°C and 61) ofthe CH4. The 61m0 value of the water sampleswas determined using a modified C02-H,Oequilibration method as originally described inEpstein and Mayeda (1953), with modificationsdescribed in Hackley et a (1999). The 81) ofwater was determined using the Zn-reductionmethod described in Coleman et al. (1982) andVennemann and O’Neil (1993), with modifications described in Hackleyetal. (1999)The 6°Cof DIC was determined using a gas-evolutiontechnique. Approximately 10 niL of water wereinjected into an evacuated vial containing 100%phosphoric acid and a stir bat The CO2evolvedfrom the water sample was cryogenically purified on a vacuum system and sealed into a Pyrexbreak tube for isotopic analysis. The 3245 of theSO was determined by precipitating the SOas Ba504 and converting the sulfur to SO, bycombustion with a V,O,-SiO, mixture, simnilar to that described by Yanagisawa and Sakai



(1983) and Ueda and Kmuse (1986) The 6°Cand 3D values of the CIT4 samples welt deterrnined by cornbusting the CIT4 and collect

ing the products CO2 and 11,0 as described byHackley a a (1999)

The 3D. 6°C, 6”O, and 8”S values were

determined on a dual inlet ratio-mass spec

trorneter. Each sample was directly compared

to an internal standard calibrated venus aninternational reference standard, The final at-suits are reported versus the international refertoce standards. The 3D and 3180 results arereported versus the international Vienna Stan

dard Mean Ocean Water (V-SMOW) standant

The 8’3C results alt reported versus the Peedeebelemnile (P1)8) reference standard The &MS

results axe reported versus the Canyon triableTroilite (CDT) standard Analytical reproduci

bility for 3D. 80, 6°C, and 3’S is equal

to or less than ±L0%0,±O.l%, ±0.15%,, and

±0.3%, respectively.Radioisotope analyses included ‘H on the

water and ‘4C on the DEC. The ‘H analyses were

done by the electrolytic enrichment process

(Ostltrnd and Dorsey, 1977) and the liquidscintillation counting method The electrolytic

enrichment process consists of distillation,

electrolysis, and purification of the ‘H enrichedsamples. The precision for the tritium analyses

reported in this study is ±0.25Th-The “CD activity of the tIC was analyzed us

ing conventional techniques, and results were

corrected foç 3°C compositioo& The tIC was

extracted flour the water samples by acidifi

cation; the released CO, was quantitatively

collected on a vacuum line. The CC), fromacidification was cryogenically purified andconverted to benzene as outlined in Coleman

(1976). The “C activity was measured using theliquid scintillation spectiometty technique developed by Noakes et at (1965, 1967). The “Cresults are reported as percent modern carbon

(pMC) relative to the NBS reference material

(oxalic acid #1). Modern carbon (100 pMC),

by convention, is defined as 95% of the activity

of the oxalic acid reference standard (Clark andFritz, 1997).

RESULTS AND DISCUSSION

The chemical and isotopic results (GSA DataRepository, Tables DRI, DR2, and DR3’) showimportant patterns across the basal sands of the

Mahomet aquifer and Sankoty Mahomet —-

let Four hydrocbemical fades were observed in

‘GSA Data Reposiny item 2C09286, data tables andadditional text and figures referred to in the main document, is available at buJAwwgeeiociety.org4xrhsIft2009Jsin orby mauen tor*fiting@gecsodctyorg

the basal sands of the Banner Formation, eachof which bad different “C andlor 3°C chaxacteristica Groundwater in the central and easternregions of the Mahomet aquifer (Champaign

County, southern Ford County. and pails ofWrmillion County) is primarily Ca-Mg-HCO, waterwith very low Cl concentration and ‘4C valuesaround 30 pMC. Groundwater in the western region (Piatt County, DeWitt County. andMcLean County) is a Ca-Mg-HCO, water witha notable influence from Na-Cl-type waters.Groundwater in this western region also shows

decreasing “C values toward the west and thegreatest 6°C values observed for DIC comparedto the rest of the Mahomet aquifet Groundwater

in the northeastern region of the Mahornet —-Icr (the Onarga Valley), in Iroquois County andparts of northern Wrmillion County, is primar

ily Ca-Mg-LICE), with seine Ca-Mg-SO4watersand exhibits smaller ‘4C con’cenirations and amnegative 6°C values than the central and east

ern regions of the aquifer. The groundwater

in the Sankoty Mahomet aquifer is primar

ily Ca-Mg-LICE)3water with variable Nr andCt concentrations and a large range of “C and3°C values, The dominance of major cations

and anions for the different fades is shownin a bilinear diagram Qi8 5). These resultssuggest trends horn Ca-Mg-HO)3 waters toCa-Mg-SO4-and Na-Cl-type waters In theaquifers of the Mahomet bedrock valley system,based on the generalized evolution of groundwater due to water-rock interactions (Orebotarev,

1955; Schoeller, 1939). However, as indicated inthe following discussions for each region of theburied bedrock aquifers, many of the chemical

variations observed are actually due to mixingof younger, more dilute groundwater with older,more mineralized groundwater seeping frombedrock units in the various regions of the bedrock valley or mixing of relatively fresh rechargewater with groundwater emerging from a partof the Pleistocene aquifer that is more confined,

The isotopic composition (&‘O and 3D) of mostof the water sampled from the Mahomnet andSankoty Mahomet aquifers is similar to present-day precipitation, suggesting the age of the wateris no older than the start of the Hotocene. ‘Thereare a couple of samples that have slighdy morenegative isotopic compositions, and these are in

regions of the aquifer that have evidence of in-puts from bedrock units.

/a

4;

/

A MA - Confluence

• MA-WesternO MA - CentrallEaslern

I MA-NorTheastern

a GA-Confluence

U GAO-tenry-Westem

0 GAiHenry - Centrair’Eastem

X GA-Northeastern

0 Bedrock

‘S/

‘S./

—a--.

Figure 5. ‘1¼-ilinear and piper diagrams of groundwater samples from the Mahomet bedrock

valley hydrologic system. Different symbols represent samples from the Mahomet and shal

lower aquifers in the different regions across the Mabomet Valley. Bedrock data are from

Panno et at (1994). Arrows depict geochemical evolutionary trends observed in the western

and northeastern regions.


Hackley et aL

Central-Eastern Mahomet Aquifer Region

Groundwater in the central and eastern regions of (he Mahornet aquifer has the smallesttotal dissolved solids content, as exemplified bythe small CMO&Ie concentrations (Fig. 6) andthe relatively low specific conductance values(F1g DRI (see footnote lfl. The low specificconductance and chloride concentrations suggest significantly less water-rock interactioncompared to the rest of the Mahomet aquifetThe relatively dilute nature of this groundwaterled Panno a a (1994) to suggest that there ismore rapid recharge from the surface in the central region than the western and northeasternregions of the Mahomet aquifer. The greater “Cactivity in central-eastern area of the Maboruetaquifer, near 35 pMC (Fig. 7). supports thishypothesis. There is an unusually thick sequence of stacked sand deposits (Panno et aL1994; Hackley, 21X12) in the central region ofthe Mahoniet bedrock valley that corresponds tothe pcitentiometric high (Fig. 4), providing additional geologic and hydrologic evidence thatthe area is an important recharge zone for theMahornet aquifet

Typically, assuming the lithology and geechemistry of the local geology and aquifersait similat, one would expect the activty in the groundwater near a recharge zone toie relatively large compared to groundwater ata similar stratigraphic level further away fromthe recharge zone. Most wells screened in theGlasfoni Formation in Champaign and FordCounties, had relatively large “C activities (58—65 pMC), as would be expected for arelatively shallow aquifer near a recharge zone.However, the‘4Cnc results from a few wells inthe same area suggest the situation is complicaled. For example, one of the Glasforid wells,BRND-99, on die bonIer of southern FordCounty and northern Champaign County, had arelatively low “C activity (281 pMC) awn-pared to most other wells drilled to a similarstratigraphic level in the bedrock valley (TableDRIB [see footnote I fl. Relatively low “Cvalues were also observed in other wells in theGlasfonl aquifer (CHM-94B and TM-0O), aswell as in the Mahomet aquifer (CHM-94A andWJ-00), which an located in or near the samearea of stacked sands and topographical high innorthern Champaign and southern Ford Counties. Biogeochemical reactions such as sulfatereduction and methanogenesis may help to explain the lower “C values in these wells. The6”C values for some of the wells are more negative (<—l4%o) than most of the other wells in thecentral and eastern regions, suggesting the input

f isotopically lighter carbon, probably due tooxidation of organic matter related to the sulfate

reduction. Most of these wells with low 8’3Cvalues also had positive &S values, with concentrations ranging from below detection limitsto 51 rngs’L (Fables DR2 and DR3 [see footnote 1)). The well with no detectable sulfate,BRND-99. had detectable 04, suggesting thatafter sulfate concentrations were depleted, fa’mentation reactions associated with methane-genesis took over, which could have contributedadditional “C-depleted bicarbonate to lower

values. The fermentation reactions thatoccur along with methanogenesis break downcomplex organic compounds into simpler molecules such as fatty acids, carbon dioxide, protons, and hydrogen (Klass, 1984).

Northeastern Mahotnet Aquifer(Onarga Valley) Region

Groundwater in the Onarga Valley, the segment of the Mahomet bedrock valley that trendsnorth-northeast, contains low 14C activities(Fig. 7) and high S0- concentrations (Table

DR2 [see footnote I]). The bedrock consistsof Silurian and Devonian marine limestonesand dolostones and Pennsylvanian shales,sandstones, and coals. P’anno a ak (1994) suggested that the sane of the high S0 concentrations is the dissolution of sulfate mineralsassociated with the weathered bedrock unitaBecause of the minimal amounts of dissolvedoxygen available in groundwater, the SO concentrations observed in the Onarga Valley arenot possible by pyrite oxidation alone but areplausible by dissolution of sulfate minerals asdetermined by geochemical modeling (Pannoa al., 1994)- The additional low (negative) ÔSresults for samples with large S0- concentrations reported in this study support the suggestion that the sulfate minerals being dissolvedwere originally derived from the oxidation ofpyrite in the Pennsylvanian coal and shales aswell as Devonian shales. The 3)45 associatedwith sulfur from reduced sulfides such as pyriteare typically negative (Hackley and Anderson,1986; Kaplan, 1983; Goldhaber and Kaplan,

western cenfraf northeast easternconfluence MA MA AM MA

.

+

A. ••.A

A

• MA-west• MA-canlratastI MA-oo.lt’ioastA SMA-confluonceEl Glastoid-westA Gtastord-conltuenceo Gtasford-centnj-east

X Gtasford-northeast

+ stiaHow

1000

100:

-J

Eo 10-o0 -

-c -

0 -

0.1

AK 1 o

A W 0& 00 Xz

A 8 I. I

AK

0•

•

•o

I I I I , I , t I I I II I • I ‘ I I ‘ I

100 200 300 400 500 600 700 800

West-east coordinates

Figure Distiibution eta concentrations for groundwater samples plotted geographicallyacross the Mahoanet bedrock valley system. Different symbols are used for different regionsof the Mahomet Valley. Closed symbols are samples from the Mahomet aquifer, while opensymbols are from the shallower Glasford and Wedron aquifers (Coordinates used for x-axisare Illinois plane coordinates divided by 1000; see location ramp Fig. 3.).



1980,1974). Prior to deposition of the Pleistocene sediments, bedrock units exposed in thevalley would have undergone weathering fora prolonged period. For example, secondarygypsum and iron-sulfate formation hun pyriteoxidation has been observed in recent soils andlignite overburden piles (Wagner a al., 1982;NettletonetaL, 1982; Dix(metaL,l982)Thus,gypsum and iron sulfates may be present in theweathered bedrock surface of the Mahometbedrock valley in this region

If gypsum is present at the base of theMahomet bedrock valley, along with dolomite and calcite, then them is the possibilitythat de-dolotnitization may be occurring inthe Onarga Valley rtgioa De-dolomitizationhas been reported in otheraquifers containinggypsum in the presence of limestones and dolomite (Back and Hanshaw, 1970; Wigley et aL,1978; Racket aL, 1983; Plummer et aL, 1990).Although no physical evidence of gypsum wasreported in the geological logs from the drillingrecords in the northeastern Mahomet aquifer,the trends observed between concentrations of

northeast easternMA MA

Ca, Mg, and HCO, venus SO4 suggest that dedolomitization has probably occurred (see GSAData Repository [see footnote lfl.

The relatively low “Cm., activities in boththe Mahomet aquifer and shallower Glasfordaquifer in the Onarga Valley region (Fig. 7) artconsistent with upward movement of groundwater passing through bedrock units up intothe Pleistocene deposits in the central part ofOnarga Valley (Hamdan, (970). Dissolution ofthe Paleozoic bedrock carbonates would add“C-free carbonate ions to the DIC pool, dilutingthe “C activity. In addition, 8”C values in thisregion are unusually negative (—l4% to —2l%)(Fig. 8; Table DR3 Isee footnote II), suggestingthat oxidation of organic matter has also contzibutedto the DIC. Organic carbon, dissolvedor sedimentary, would be isotopically depletedcompared to the DIC of groundwater. For example, the 6’3C values of sedimentary organicmatter collected from glacial deposits throughout illinois range between —24% to —30% (Liuand Coleman, 1981; Liu er al., 1986). Thus,input of dissolved CU, from the oxidation of

organic compounds would shift the carbon isotopic composition of the DIC to more negativevalues. The high SO concentration observed inthe groundwater of this northeastern region is alikely source of electron acceptors for anaerobicoxidation of organic mallet within the aquifer.Dissolved CU, from the oxidation of DOC orsedimentary organic matter originating from thellhinoian or pre-lllinoian Pleistocene sedimentsor the Paleozoic bedrock strata would also dilutethe “C content Thus, the low‘4C. concentralions in the northeastern region of the Mahometaquifer can be attributed to a combinationof older groundwater passing through previously exposed bedrock valley units, resultingin the dissolution of sedimentary carbonates,plus the oxidation of buried sedimentary organicmatter through sulfate reduction.

The relationship between 3S and [SO1 inthe northeastern region and surrounding areasof the Mahotnet bedrock valley can be used toestimate the relative importance of SO reduction and groundwater mixing as the controllingfactors for the variable SO concentration oh-

— served in the Mahomet aquifer (Fig. 9). Becausemuch of the Onarga Valley is topographicallylower than surrounding areas, groundwater

E could be percolating down in the perimeter regions of the Onarga Valley and flowing throughand mixing with groundwater from bedrockunits. l’hus, the isotopic composition and concentration ofSO observed in the shallow sandsof the Wedron and Glasford Formations, as wellas the Mahoniet aquifer beyond the immediatevicinity of the Omarga Valley, would be important to consider for evaluating mixing and sulfate reduction influences. The mixing curve inFigure 9 was calculated using the groundwatersamples from the vicinity of the northeasternMahomet bedrock valley with the highest andlowest SO concentration and their respective8’S values as end members. The Rayleigh fractionation curves in Figure 9 were calculated using a fractionation factor of cx = 1.015, whictis reasonable for fresh groundwater systems(Busby et al., 1991; Eberts and George, 2(X)).The different calculated Rayleigh curves showthe trends that would be expected if the sulfatereduction process were initiated at differentSO concentrations. The trend of PS valuesand SO concentration for most of the samplesfalls closer to the mixing relationship ratherthan the Rayleigh fractionation curves, especially the overall fractionation curve initiatedfrom the highest SO concentration.

Although SO reduction is probably not thedominant process responsible for the decreasein S0- concentration in the Mahomet aquifer in the northeastern region and surroundingareas, the PS and (SO1 data do show that

western centralconfluence MA MA

+

A

100--

80--

60--

0

aQ4fl.

20--

+

0

A0

• MA-west

+ • MA-central-east

I MA-no.Theast

A SMA-contkjence

0 Glastoid-west

A Glastoid-confluence

o Grastoni-central-east

o K Gasford-northeast

+ shallow

SI7A

0

00

0

0

. .A0

A o e. 0

A0

A

aA?

i. I

.

0

Iax

0 I I ‘ I

100 200 300 400 500 600 700

W Tazewell McLean DettrsttPlatt Chan7Pal9K’7q1,,,5 ii

Figure 7. “C activity of dissolved inorganic carbon (DIC) for samples taken from the

Mahomet bedrock valley system plotted geographically from we to east across the bedrock

valley, Different symbols are used for different regions of the Mahomet Valley. Closed sym

bols are all from the Mahoinet aquifei while open symbols are from the shallower Glasfordand Wedron aquifers,


Hackley et aL

-25 -

___

100 200 300

so:— reduction is definitely occurring, and insome cases may be dominant The very posi—the 8M5 values in groundwater from shallower

sands (+15%. to +30%c) overlying the Mahoinet

aquifer in the Mahomet bedrock valley (centraleastern and the western regions) are most likelydue to SO reduction. The primay source ofdissolved so:- in the shallow tills would be theoxidation of pyrite, which typically has negative

6’S values (-10%. to -l6%. according to VanStempwroa et aL 1994). The low SO concen(rations and very positive 8”S values measured

in samples 1mm these shallower aquifers areprobably characteristic of the SO in groundwater that eventually infiltrates the deeper

Mahoinet aquifer in arms of downwaM gradi

effis. In addition to these shallower groundwater

samples, one of the deeper samples (l98C) in

the Mahomet aquifer in the northeastern region

also had a very positive 8”S value (+57%.),strong evidence of SO reduction being adominant process for this site. TIre 8’S values

of other samples from the northeastern region

suggested that SO reduction has overprinted

the general mixing trend exhibited for most of

the Mahomet aquifer samples in the region. Forexample, assuming the chosen end members arecorrect, groundwater at sites 198B, 195A, andespecially 198D have significantly more positive&S values than would be expected 1mm mixing alone, The more positive P’S values at thesesites ale likely due to microbial 5O reductionoccurring in conjunction with mixing. Groundwater at sites 196A, V94A, and 12 also appearsto have been slightly influenced by SOt reduc

don processes (Fig. 9). Sulfate reduction in theMahomet aquifer samples is supported by their

mote negative 8°C values relative to most ofthe other samples in the central and eastern por

tion of the Mabomet aquifer (Table DR3a [see

footnote 11; FIg. 8). The more negative 513C val

ues suggest an input of isotopically light carbon

by the oxidation of organic matter, which would

occur during the SOt reduction process.Thus, the chemica] and isotopic data sug

gest that the wide range in SO concentrations

in the eastern half of the Mahomet aquifer iscaused by a combination of groundwater mixing and reduction. Mixing occurs betweenupwelling high-SO:- groundwater from the

Onarga Valley in northeastern region and lower

so:- groundwater in the basal Mahomet sandfrom the central region. The Large SO concentration in the Glasford Sand and Mahometaquifer in northern Vermilion (V948&A) suggests that the upwelling groundwater from theOnarga Valley has also mixed with groundwaterin parts of Vermilion County. In the rest of theMahomet aquifer, it would appear that groundwater from the shallower aquifers has percolateddown to the Mahomet aquifer, with 5O subjected to various degrees of sulfate reduction.

The microbial SOt reduction contribstes to thedecrease in SO- concentration as well as an in-crease in the P’S of the remaining SOt. Thisreduction process also results in more negative

values and adds to the dilution of “Cactivity of the DIQ which is already low in thenortheastern region of the Mahomet aquifer as aresult of the upwelling older groundwater fromthe bedrock in this area.

Besides the elevated SO concentrations,groundwater samples in the vicinity of thenorthwestern region are anomalously high inother constituents including B and Sr, whichappear to be related to the local lithology(Hackley, 2002; Table DR2; Figs. DRS and1*4 [see footnote 11). Boron is typically associated with minerals such as tourmaline, bintire, and amphiboles (Hem, 1992) or perhapswith shales arid coals (Krauskopf, 1967). TheUpper Devonian New Albany. the Mississippian Bordin Siltstone, and the Pennsylvanian

Tradewater Formations exposed in the bedrock in the northeastern and central pasts of theMahomet bedrock valley (Kolata et aL, 2005)

contain shales, coals, sitstones, and argilla

ceous sandstones, some with noticeable micaflakes (Willman et aL, 1975). and they are probably the primary source of the elevated boron inthis part of the Mahomet aquifer. The source ofSr is probably the Mississippian, Silurian, andDevonian carbonates (F1g 3) or clastics fromthese formations, which make up most of theexposed bedrock for this region of the valley.

Western Mahomet Bedrock Valley Region

Within the transition zone between the centraland western regions of the Mahomet aquifer,there appears to be a fraction of rather younggroundwater percolating down through sandunits beneath the Sangamon River, as indicated

by the tritium results. Two groundwater sampleshum the basal sands in this region contained asmall amount ofdetectable tritium (Table DR3A[see footnote I]). The tritium data suppoxtrecent

seismic and water-well pumping studies that indicate there is a hydraulic connection between

the Sangamon River and the Mahomet aquifer in

western central northeast easternconfluence MA MA MA MA

5

0

-5

0Co

—15

tli.

ALLAN Nt)

A 0N N

A N

a 0

“N •°A S

•0I

• MA-west

• MA-control-east

I MA-northeast

A SMA-conifuence

El Glasford-west

A Gtaslord-cootluence

o Glaslord-central-east

K Glasford-norttieast

0

.S

IXII

K

I • I • I • I • I •

400 500 600 700


800

FigureS. D€ttrihudon of values for groundwater samples plotted geographically

acro the Mabonet bedrock valley system. Different symbols are used for different regions

of the Mahomet Valley.



this area (Carstens, 2004; Roadcap and Wilson,

2001). The “C activity of these two samples did

not show an increase; in fact, the “C of one was

similar to other samples in the central region

(30 pMQ, while the other sample was — low

(II pMC). suggesting that there has been sig

nificant amounts of groundwater with less than

30 pMC mixing with the younger waler perco

lating down from near the surface. There was

also CH4 detected in the Mahomet aquifer and

Glasford aquifer in the same area, indicating

degradation of buried organic debris (including

fermentation reactions), which would tend to di

lute the “C activity of the DUD as well as influ

ence the 8°C and concentration of DIC.Just west of the boundary between the cen

tnt and western parts of the Mahoniet aqui

fer, (in Plait County), SO concentrations

drop to very small values, often below detec

tion limits, and Cu4 concentrations increase

abnzptly (Fig. 10). In the sequence of microbial

reduction processes, SO is consumed prior to

microbial production of CH4 (Oremland and

Taylor, 1978). This is because SO-reducing

bacteria are more efficient in utilizing the avail

able energy sources, such as hydrogen and ace

tate. and out-compete methanogens (Martens

and Bernet, 1974; Abram and Nedwell, 1978;

Kxistjansson eta!., 1982). Thus, in groundwaterwhat methanogenesis occurs, SOt concen

txations are usually quite small or not detect

able. The 8°C and 81) values of CH4 from theMahomet aquifer indicate that the CR4 is ofmicrobial origin, formed by the CO2 reduction

pathway (Fig. II). This is in agreement with the

results of Coleman et al. (1988). who studied

the origin of Cl4 in several glacial drift andshallow Paleozoic deposits throughout flhinoi&

The western Mahomet aquifer also shows aneast-west trend of progressively higher specificconductance (Fig DRI [see footnote II) and

a- concentrations (Fig. 6) compared to the rest

of the aquifer. Sodium concentrations also In

crease in this part of the Mahomet aquifet Theincreases in Na and Ct concentrations suggest

contribution of more saline groundwater from

bedrock units. The main influx of saline ground

water probably occurs near the west flank of the

La Salle anticlinorium (Panno et a!., 1994). Thelargest concentrations of Cl- and the lowest “Cconcentrations observed in this study were fromsamples located in Piatt County, just west of theOsman-Charleston monocline (Fig. 3). whichis associated with the La Salle anticlinorium incentral illinois.

Both the change in bedrock lithology (Fig. 2)associated with the Osman-Charleston mono-dine and the seepage of groundwater from bedrock units in the western region of the Mahometaquifer may contribute to the strongly ‘educingconditions, as indicated by the disappearance ofSO and elevated levels of CH4 concentration

as one moves further west along the Mahometaquifer from the central region. The units exposed along the bottom of the bedrock valley

in the western region ale the PennsylvanianModesto and Bond Formations (Kesnptoueta, 1991; Willman et a!., 1975). These Pennsylvanian shales, coals, and argillaceous lime-stones, or perhaps clastics from these units, inthe western part of the Mahomet bedrock valley probably contain relatively large amounts ofsedimentary organic matter, which would resultin more rechicing conditions compared to theMahomet aquifer overlying primarily carbonatebedrock units in the central and eastern regions.Organic carbon is a strong reductant and an important substrate for many microbial oxidation-reduction reactions (Swrnm and Morgan, 1981).Influx of groundwater from the organic-bearingbedrock units may contain high levels of DOC,or DOC may be leaching out ofclastics from thebedrock units, which would enhance reducingconditions in this part of the Mahomet aquifer.The data shown dramatic increase in DOC inthe western part of the Mahornet aquifer thatstarts rather abnrptly near the Piatt-Chanipaign

County line (Fig. 12). However, the constituents

that indicate strongly reducing conditions (Cl!4and NVOC) do not correlate well with the in-creased Ct concentrations, which are believed

to be associated with upwelling groundwaterfrom the bedrock units in this region. For example, the correlation coefficient (r2) betweenCt and CH4 is 0.25, and r2 between a- and

NVOC is 0.04 for the western Mahomet aquifec Furthermore, some of the samples from theshallower Glasford aquifer, especially in thewestern region, also have quite elevated NVOCvalues (as high as 83 mglL with a meanof4.l;Table DR2B (see footnote II). Thus, a substan

tial amount ofthe DOC in the western Mahometaquifer may be associated with the paleosolsand peat deposits often found within the gla

cia! tills themselves, typically located between

the Pleistocene formations (Fig. 2) (Kempton

eta, 1991). The organic matter associated withthe Pleistocene deposits is much younger and

60

50

40

30

20

Co

0

FIgure 9. 3”S versus ESO1 for groundwater samples collected from the Mahomet aquifer

and stallower sands. Diagram includes a calculated mixing curve and Rayleigh fraction

ation curves to help deternilne whether physical mixing or redox processes are affecting the

variability of [SOfl The multiple Rayleigh curves show how sulfate reduction reactions

could overprint the overall mixing process. (‘lick marks on Rayleigh tunas indicate frac

tion of original i5ø-i remaining.)

0 200 400 600 800

Sulfate (mgt)


Hackley et at.

fuse into aquifers from surrounding aquitanis;

thus, the elevated levels of NVOC in the westernportion ofthe Mahomet aquifer ale probably dueto a combination of influx from the surroundingtills and the organic-rich Pennsylvanian bedrockwilts. Another consequence of the strongly it-

ducing conditions and minimal SOt concentrations in the western part of the Mahomet aquiferis the elevated concentrations of arsenic (As)observed in this area, which are believed to bedue to its mobilization from the reduction ofiron oxyhydroxides wilhin the aquifer sands andgravel (Kelly, 2005; Kirk et a, 2004; Warner,2001; Panno et al., 1994).

The “C activity and the 6°C of the [MC inthe western region of the Mahomet aquifer arequite different compared to the central region.Them isa progressive decrease in “C westwardin the thalweg of the Mahomet bedrock valleytoward the confluence area (Fig. 7), and the 6°Cvalues am more positive (Fig. 8). Them axe sevcml possible masons for the lower “C activity ofthe DIC in the western portion of the Mahometaquifer, including: influx of older groundwaterhorn bedrock, Cl-I4 production, and isolationfrom surficial recharge. The simplest explaintion is that groundwater in this portion of theMahojuet aquifer is more isolated from surficialrecharge and simply ages as it slowly moves

— westward. However, the strong reducing condi

800dons associated with larger DOC concentrationsand CH4 production also help to explain thelower “C activity. The elevated concentrationsofCH4 suggest there has been excess CO2addedto the water by fermentation reactions associated with methanogenesis. In the Mahomnetaquifer, the microbial reactions associatedwith methanogenesis would generally add “Cdepleted carbon to the groundwater, increasingthe [MC concentration, diluting the ‘C contentand altering the 8°C of the ftC. As observedin other aquifers where methanogencsis ocairs(Batter and Fritz, 1981; Grossman et aL, 1989;!-lacldey et aL, 1992; Arevena et at., 1995),

••I MA.io.theast

A SMA-cnnft

o 01std-west

A GImd.cuin

o 01sf rd-at-east

confluencewestern central northeast eastern

MA MA MA MA0.004 -

0.003 -

0.002 -

0.001

0

-j

0C0C

-c

A • MA-west• MA-cootmi-eastI MA-northeastA SMA-conihience

A 0 GIasfocd-west

S A Otastoni-confluence0 GIasford-central-east

• o • X Glasfoid-no.ttieast

A

A

0

A U0

. I

A 5 a.AC I a I arrta.°Q

I t.141 ‘ I I — — waa,aI

100 200 300 400 500 600 700West-east coordinates

Figure 10. Methane concentration for groundwater samples versus geographic locationfrom west to east in the aquifers of the Mahoinet bedrock valley system.

should be more labile compared to the Paleozoic bedrocks; howeveu the substantial increasein NVOC geographically correlates with thechange in bedrock lithology from carbonates toPtnnsylvanian shale and coaL As indicated byMcMahon and Chapelle (1991), DOC can dif

-120

-160

—240

—280

0

010

Figure 11. 8D and 8°C ofCl4 from groundwater of theMahomet bedrock valley system. Enclosed areas representisotopic compositions typicallyobserved for different sourcesof methane (Whiticar et al.,1986; Coleman et ul., 1993;Hackley et aL, 1996). -320

-360—90 —80 —70 -60 —50 —40 —30

6’C (%)

1058 Geological Society ofAmerica Bulletin, July/August 2010


sigHificantly more positive 5”C values occurin the western region of the Mahomet aquifer compared to the eastern half of the aquifer

(Fig 8)- The increased 8”C values primarily re

sult from the fractionation effect associated withmethanogenesis in which the isotopicafly lightcarbon (“Q is1referenfially used in the microbial process to produce CH4, leaving the remaining CO2 enriched in “C. Additionally, inputs of

CO2 due to fermentation reactions could alsoresult in dissolution of carbonates, which axerelatively enriched in “CD (8°C — O%c Ander

son and Arthur, 1983). Thus, the carbon isotopicfractionation associated with methanogenesisand the dissolution of carbonates would overwhelm any isotopically light carbon input fromthe fermentation reactions of organic mailer(“C-depleted carbon). It is also possible that theC114,orat least some of the Cl4,may be associated with the upwelling saline water from thebedrock units, which would add “C-depletedand possibly °C-emiched DIC to the westernportion of the Mahomet aquifer, diluting the “Cconcentration and increasing the 8°C values.Unfortunately, we do not have any groundwater

samples from bedrock beneath the Mahometbedrock valley, but a sample collected where thePtnnsylvaniaa bedrock is closer to the surface(112 m), —40 km to the southeast, contained significant amounts of methane and had avalue of +25%a

Although methaaogenesis and the influx ofolder bedrock water are important, these do notappear to be the only causes for the progressive decrease in “C observed in the westernMahoniet aquifer system. Sample KRK-99 hasa high concentration of Cu4 but a “C valuethat is only a few pMC less than those samples up-gradient just to the east (WRD-55 andCHM-95fl). As previously discussed, there isalso evidence that the area near KRK-99 maybe close to stacked sands, as indicated by thecross section in Figure 13, and/or a groundwater window where recharge from the surfaceis mote open compared to wells sampled towardthe east and western parts of the Mahomet aquifer. Thus, isolation from surficial recharge andnatural radioactive decay must also contribute to

the progressive decrease in “Cnc activity in thewestern part of the Mahonet aquifer.

20

Confluence and Sankoty-Mabomet Region

15-

10-

• MA-central-east

I MA-norTheast

A SMA-confluence

OiC0

0

>z

o Glasforci-west

A Glasford-ceoffuence

o Glasford-central-east

X Glasford-northeast

+ shajiow

0

‘p...

S5

0

0

I

A

A1

A

0

IaS • xr *.°Jt.7

. cr0I •

I ‘


Figure 12. Distribution of dissolved organic carbon (as nonvolatile organic carbon [NVOC))in Mabomet bedrock valley system.

western central northeast easternconfluence MA MA MA MA

A Within the Sankoty Mahomet aquifer, the

•chemistry becomes more dilute, specific conductivity decreases (Fig. Bitt (see footnote I]).

-

-Cl concentration decreases (fig. 6), Cl4 concentiation decreases (Fig. 10), and the “C values increase sharply (Fig. 7) compared to theup-gradient western part of the Mahomet aquifet These trends suggest that there Is significantflux of younger freshwater into the SankotyMahomet aquifer in the confluence area Thisfits well with the decreased amount of glacial tillcovering the sands in this region (Herzog eta,

A1995). The samples containing the highest C1

S and Cl concentrations and lowest “C activitiesin the c nfluence area tend to follow a ground-

Awater divide that has an east-west trend within

AA I this area (FIg. 4). The groundwater chemistry

becomes more dilute and has greater “C activity

-- A

I asthewaterflowstothesouthandnorthawayfrom the groundwater divide and around a bedrock high toward the illinois Rivec The rather

•rapid change in geochemistry is strong evidencethat there i5 substantial recharge from the jrficial units to the Sankoty Mahomet aquifer in

-

________________________________________________________________

the confluence area compared to the rest of the

100 4(r) C;] D0 700Mahomet aquifer. For example, the con-elationcoefficient between Cl- and two other constituents in the Sankoty Mahomet aquifer that hadrelatively high concentrations in the westernMaliomet aquifer, CIT4 and Nt was (170 and0.68 respectively. Howevet the correlation coefficient between Ct and “C was only (152,suggesting other mechanisms besides dilutionhave affected the variability of constituents,especially “C, in the confluence area.

In addition to mixing, the microbial nesinvolved with methanogenesis appear to havesignificantly influenced the groundwater geochemistry of the Sankoty Mahomet aquifer.The 5°C value of the DIC in the confluencearea was rather enriched in the heavier isotopeand ranged from -5.7%o to -l.6% with theexception of one sample that was —9.6%. Themore positive 8°C compositions reflect the influence of microbial (314 production. The isotopic composition of the Cl4 is similar to theother samples in the Mahomet aquifer and representative of microbial drift gas (Fig. 11). Theconcentration of CIT4 in the Sankoty Mahometaquifer ranged from —(19 to 3.7 rruuol/L, whichis greater than that observed in the shallowerGlasfoni Sand (0.1-0.7 mmolIL) As discussedearlier, fermentation reactions associated withmethaaogenesis add “C-depleted CO1 to thegroundwatet The correlation coefficient between the Cl4 concentration and “C activity ofthe DIC is (190 (FIg. 14). Thus, it appears thatthere is an additional input of microbial methane


Haddey et aL

FIgure 13. Cross section (B-B

of the Mahomet bedrock valleyincluding “C, ISOfl and IClidata for several wells (modifiedfrom Hackley, 2002). Note thelower “C activities and higherCt concentrations near the

sides of the valley, especially on

the west side where the bedrock

is all Pennsylvanian deposits.MSL—mean sea level.

Vertical exaggeration = 425x

caybedrock

=‘4c UMC)1= SO (mglt)=ct (m)

=

to the Sankoty Mahornet aquifer in the conflu

ei area As in the western Mahomet aquifer.

strong rahicing coalitions associated with

methanogenesis also affect the arsenic concen

trations, which are relatively high in the conflu

ence region (Kelly, 2005; Warner, 2001; HoIm,

1995). Thus, although a good deal of (he varia

bility in the geochemical composition of the

groundwater in the Sankoty Mahomet aquifer

is probably due to mixing between groundwater

Irvin the western Mahomel aquifer and fltsher

young recharging groundwater from the shal

lower zones, there is also significant influence

on the geochemistry due to the methanogenesis

processes taking place in this region.

Conceptual Model

Based on the trends in chemistry and iso

topic composition throughout the basal aqui

fers of the Banner Fbrmation and the shallower

Glasford Sands, we developed a ftindainental

conceptial model of groundwater evolution for

the Mahornet aquifer and the Sankoty Mahoma

aquifet A plot of the Ct concentration and

‘C activity across the Sankoty Mahomet

aquifer and Mahomet aquifer shows the large

variations in the data from the confluence areato the easternmost Mahomet aquifer in illinois

(Hg 15). The arrows and text on the diagrams

in Figures ISA and 153 summarize the majorinfluxes of groundwater to the Mahomet aqui

fer, depicting the overall conceptual model. Thechloride concentration is very low in the central

part of the Mahomet aquifei while the “C activity of the InC has seine of the largest values(excluding the Sankoty Mahomet aquifer in (he

confluence region). These observations supportPanno et aL’s (1994) suggestion that the centralarea of the Mahomet aquifer is the primary recharge area This is consistent with historical

head data published by Kempton et al. (1991).

which thowed a potentiometric high in the north

ern Champaign and southern Foci Counties

area Recent bead measurements for the aquifer

also indicate potentiotnettic highs in the area

of southern Fond County and near the Illinois

Indiana border, with flow primarily to the south

andwest(WilsonetaL, 1998; Roadcap and Wil

son, 2001). The geochemical data ale also con

sistent with the geology, which indicates that thecentral region has several stacked sand deposits,

many of which appear to be connected. The

stacked sand deposits may help explain the very

low Cl- concentrations (ft6-23 mg/L) observed

for much of the central Mahomet aquifer region.

Such low Cl- concentrations suggest that this

area was flushed with high volumes of fresh

water, perhaps from glacial nieltwaters, which

leached much of the more soluble minerals from

the stacked sand deposits.The large range of SO and fl values

plus the more negative 6’3C values and low “C

B

tO

C.)

a0

9(It) (in)

230

cc215 0

in

200

185

B’

700 -

650

U

170

155

-Jin

a55° -

naCa

‘pea

w

w

35t

ThickPennsylvanian

deposits140

- 125

bedrock

-110

ThinPennsylvanian

deposits

and

a

_g5 5 0

___________________

5 0 5 15 --25_3akm

<t2

10 15 20m1 $

l060 Geological Society of America Bulletin, July/August 2010

Chemical and isotopic indicators ofgrowzdwater evolution

80

60- -

50--

40- -

30--

lo

u- -

0 0.001 0.003

70- -

C)a

C)

A SMA-confluence

A GIaSIOrd-VOOIIUeIIce

A

tAAA

A

A

A

A

A A

I • I

DM02

Methane (molt)

FIgure 14. Comparison of “C and CH4 concentration in the confluence region; r’ for the

rock land surface. The SI) and 6hbO values formost of the groundwater m the Mahomet aquifer and the shallower Glasford sands art quitesimilar to present-day precipitafioa These dataindicate that there is little to no Pleistocenewater remaining in the aquifer system, puttingan upper age limit for most of the groundwaterat the start of the Hotocene, en. 11,000 yr B.P.The tritium results indicate that there is modemrecharge into the Wedron sands and some of theGlasford sands, but very little modem water occurs in the basal sand of the Mahomet bedrockvalley. Of the sites sampled, only one area inthe Mahomet aquifer near where the SangamonRiver crosses the bedrock valley had detectible

tritium. These Iritium data are consistent withrecent seismic and monitoring well drawdownstudies by the ISGS and ISWS that have suggested a hydraulic window where groundwater

discharges to the Sangamon River when theriver is low and groundwater recharges duringperiods of high stage or excessive groundwaterpumping (Roadcap and Wilson, 2001).

The central-eastern region of the Mahornet— aquifer contained the highest ‘4C activity and0.004 most dilute groundwater compared to the rest

of the Mahomet aquifer, indicating that thegroundwater in this region has gone throughthe least water-rock interaction. These isotopicand geochemical characteristics imply that thisregion is the area of most rapid recharge formost of the Mthomet aquifer. as proposed by

ley, especially close to the Pennsylvanian-age Panno a a]. (1994). The very low Ct concen

bedrock on the western side of the aquifer (see trations in the central Mahomet aquifer region

Rg 3 for bedrock lithology). This empha- suggest that high volumes of freshwater (glacial

sizes the relationship of the Lknnsylvanian-age meitwatets) probably flushed the stacked sand

bedrock to the seepage of older mom saline deposits and leached the more soluble minerals

groundwater into the western Mahomet aquifer so that the present-day groundwater has tela

compared to the carbonate bedrock in the ceo- lively low dissolved solids concentration.

in1 portion of the Mahomet aquifer. The chemical and isotopic results for the

As the groundwater horn the Mabornet aqui- Mahornet aquifer in the western and northeast

fer flows into the Sankay Mahomet aquifer, the an (Onaiga Valley) regions indicate that these

chemical composition and LC activity change areas of the aquifer are relatively isolated from

dramatically- hi this confluence area, the geo- surficial recharge and have been significantly

chemical makeup of the groundwater of the influndbytheinntionofol&rflow’4C

basal Pleistocene sands and gravels is strongly activity) groundwater from bedrock units with

influenced by a combination of relatively rapid greater dissolved ion concentrations. The en-

recharge of younger, more dilute water infiltrat- richment of SO, Ca2, Mgl’, Nt. and B. and

ing from the surface and the microbial processes Sr in the Onarga Valley is probably the result of

associated with methanogenesis. water-rock interactions with bedrock litliology,including Silurian, Devonian, and Mississip

SUMMARY AND CONCLUSIONS pian carbonates and Pennsylvanian cyclothemtype deposits (shales. coals, and argillaceous

The chemical and isotopic characteristics of lirnestones and sandstones). The SS and 6’3C

the groundwater in the aquifers of the Mabornet values as well as the SO and DIC concentra

bedrock valley and atacent confluence area lions in and around the Onarga Valley region

have revealed many important aspects of the suggest that groundwater upwelling through

groundwater evolution in aquifers that have bedrock units is dissolving secondary gypsum,

been created from glacial deposits filling in the precipitating calcite, and mixing with fresher

topographic uridulations of the previous bed- groundwater in the Mahomet and (3lasford

Sankoty Mahomet aquifer data is 0.9.

activities observed in groundwater from samples

of the Mahotnet aquifer and the Glasford Sand

in the northeastern part of the Mahornet bedrock

valley indicate a mixture of deeper upwelling

groundwater and shallow infiltrating ground

water plus sulfate reduction occarring in parts of

the northeastern region of the Mahomet bedrock

valley. The mixture of groundwater finns bed

rock units in the northeastern region appears toextend into northern Wrmiffion County. The increased (I concentrations and continuous drop

in “C activities observed for the western part of

the Mahomet aquifer (Fig. 15) suggest there hasbeen greater isolation from surficial recharge

and seepage from bedrock units mixing with

the Mahomet aquifer groundwater flowing fromthe central region westward. The cross sections

that cut the Mahomet bedrock valley diagonally

(Figs. £3 and 16-17) show the relationships

among the shallower aquifers, the deep basal

sand aquifer. and the sides of the bedrock valley

from where the lithology of the bedrock changesabmptiy near the Piau-Champaign County line

to where the bedrock is primarily carbonate in

Champaign County Chloride concentrations

and C activities are included on the cross sections. The results show an increase in C1 anddecrease in “C activity near the sides of the val


Hackky et aL

-10,E

•0

0n0

Awestern central

confluence MA MA

A

northeast easternMA MA

F’—recharge

60-

• MA-west

• MA-cefleast

Z MA-northeast

A SMA-confluence

A

0

0.

0

40- -A Recharge

l.ateral flow andmixing wl recharge

20--

.

0100

FIgure 15. ‘4C activity of dhsolwed inorganic

carbon (DIC) (A) and dilo4ide concentration

(B) tor Mahmnet bedrock vaHq ground

water system and interpretation of dataB

xxxx

Bedrock upwellingfrom carb rock

1000

800

100

10

—

I I I I I I I I

200 300 400 500 600 700

W Tnewell McLean Dewitt Plait Champaij°. vemWlion E

Bedrock seepsWI •MA-west

-. Modng and isolation / • Mkceta[east

• Ill I MA-noflheast

• / A SMA-cOnOUcnce

A’1SIW Bedrockseeps

Hf• xx.

4A \ /xxmow!rect)aroe

• /4 Recharge

A •rsRecharge j

Recharge

— I I I I I I

I

0.1 I I I

100 200 300 400 500


I I

600 700 800

1062 Geological Society of America Bulletin, JulylAugust 2010


FIgure 16. Cross section (C-B’)of the Mahomet bedrock valleyinduding “C, 1SOi, and fClidata for several wells (modifiedfrom Haciley, 2002). Note thelower “C acti,itics and higherCl concentrations near thewestern side of the valley,where the bedrock is composedof Pennsylvanian deposits.MSIA—mean sea level,

(It) (m)

750- 2W

-215

65200

600’- 185

140 ThickPennsylvanian-ts

125


sands. The isotopic data also indicate that SOreduction and oxidation oforganic carbon occur

as the groundwater moves up into the Mahomet

aquifer and shallower sands. Evidence of mixing between infiltrating groundwater from bedrock in the Onarga Valley and groundwater fromthe Mahomet and Glasfmd sands extends intonorthern Vermilion County. The low “C activities observed in this area ate due to the influxof older groundwater from bedrock units, dissolution of carbonates, and oxidation of organicmatter due to SOt reductiom

The western region of the Mahomet aquiferis characterized by higher concentrations ofCH4, DOC CL Na, and HCO;, greater 6°Cvalues, and a progressive decrease in “C activities to the west The isotopic data supportthe hypothesis that the higher concentrationsof chemical constituents (especially Cr and

Na) are primarily explained by the influx ofsaline groundwater from the Ptnnsylvarüan-agebedrock (Panno et aL, 1994). Methane pioduction is undoubtedly a consequence of strongreducing conditions in this part of the aquiferThe relatively high DOC concentrations in thewestern Mahornet aquifer could also be associated with the influx of deeper groundwater fromthe Pennsylvanian-age bedrock units or perhapsleaching of organic matter in clastics from thesebedrock units and/or diffusion from organic richPlieistocene deposits. The progressive decreasein ‘C activity is probably a consequence ofseveral processes: infiltration of older groundwater from bedrock units, methanogenesis, andthe dissolution of carbonates in the aquifer, aswell as radioactive decay as the water slowlymigrates westward. The progressive decrease in“C and the lack of significant shallow sand de

posits above the Mahomet aquifer in the westernregion imply that this area is fairly isolated fromsurficial recharge.

The confluence area where the Mahotnetaquifer and Sankoty Mahomet aquifer meetshows large variations in “C activity and chemical constituents, including Cl- concentrations.This area is significantly influenced by a combination of groundwater mixing between relatively dilute infiltrating surficial water that hashigh “C activities and low Cr concentrationswith older groundwater emetging from thebasal sands of the Mahomet aquifer containing a greater amount of dissolved constituentsand the microbial processes associated withmethanogenesis.

The isotopic and chemical characteristics ofgroundwater in the basal sands of the Mahometand Mackinaw bedrock valleys indicate that

C

N‘vu)00

z B’

170

-155

-1rb

4503-Ill

450-

40

35

ThPennsylvanian

btk

110

95

Devonian andMississØpiancathooates

5 0

5 0 5

® =‘4C(pt&C)= SO (mgL)= cr (m9L)=wenn

15

10 15 2Omt- - --I

25 30km

Geological Society of America Bulletin. July/August 2010 1063

Hackley et L

FIgure 17. Cross section (1)-B’)

(It) (m)

245

230

215

200

Ins800

B’

this is a complicated geochemical groundwatersystem. The hydrochemical characteristicsappear to be controlled by a combination ofbedrock hthology and stnacture as well as thevariability of stacked sands in the Pleistocenedeposits above the basal sands in the bedrockvalley. Additional information from more detailed studies of the aquifers using geochemicalas well as geophysical tools will help to pinpointhydrologic windows in the aquifer system andquantify the influence of upwelling water frombedrock unit& Such data will assist hydrologicmodeling for predicting drawdown and futuregroundwater usage.

ACICNOWLEDGMENIS

We wish to thank the University of illinois Re“earch Board and the illinois Department of Natural

sources-Environmental Protection Tnist Fund for,snthg the funds to accomplish much of this it-

search. We also wish to acknowledge the illinois StateGeological Survey for its support and use of vehiclesand equipment We thank C.-L. (Jack) Liu, H. Wang.S. Greenberg, IL-H. Hwang, Ii. Padera, and W. Beaumont who helped with the isotope analyses and fieldwork of this project, and P. Carrillo and M. Knapp,for their generous support with their graphic artistic ability, and Brandon Cuny, for his help with thePleistocene stmtigraphic taminologyc We also thankJ. Goodwin, IX Keefei M. Kirk, S. Van der Hoven,and A. Springer for their helpful comments and suggestions to improve the original manuscript

REFERENCES CITED

Abram, J.W.. and Nedwell, DR.. 1978. Inhibition ofmethanogenesis by sulfate reducing bacteria competing for transferred hy&ogen: Archives of Mierotiotogy, V. 117, p89-92, dci: lO.10071BF00689356.

Alley, Wit., Reilly, ‘ER., and Franks. DL, 1999, Sustain-ability of Ground-Water Resources: 115. GeologicalSurvey Circular 1186, ?9p.

American Society for Testing and Materials (ASTht), 1994,Standard test method for total carbon and organic carbon in water by ultraviolet, or persulfate oxidation,

or hod,, and infrared detection, hr Annual Boot ofASTM Standards, Section II • Want and Ensisunmentat Technology, Aume II .02 Water (II). Designation:0483948: Philadel1dtia,American Society for Testingand Materials, p. 29-33.

Anderson, T.F,, and Arthur, M.A.. 1983. Stable isotopes ofoxygen and carbon and their application to sedimentologic and palnoenvironmental problems, Chapter I.it Stable Isotopes in Sedimentary Geologr Societyof Economic Paleontologists and Mineralogists ShortCourse IO,p. 1-1—1-151.

Anvena, R. Wassenaar. LI., and Plunvnes, LN., 1995, Eslimating “C groundwater ages in a methanogenic aquifer Water Resources Research, v.31. p. 2307—2317.

Bark, W., and Handsaw, BE.. 1970, Contçiaiso., of drenrical hydrogeotogy of the carbonate perinnilas of floridaand 1%rcatm: Journal of Hydrology (Ainsadanik v. I0p330—368, dci: 10A0l6/0022-t694(70)90222-2.

Back, V. Hanshaw, RB.. Plummet, LN., Rabn, P.R.Righanirt, CT., and RuNs. M.. 1983, Process and rateof dedolomitizton—Mass transfer and HC dating ina regional carbonate aquifer Geological Society ofAmerica Bulletin, v.94,p. 1415—1429. dci: 10.113010016-7606(i983)94<14t5:PARODM>2.0.Coa.

Barker, I.E. and Fritz, P.. 198 l,The occurrence and origin ofmethane in some groundwater flow systems: CanadianJournalofilarib Sciences, v I8.p. 1802—1816.

<onIi ma

flxx(JO

00

of the Mahomet bedrock valleyincludIng 14(4

LSOtL and [Clidata for several wells (modifiedfrom flackley, 2002). Bedrocklithelogy is primarily carbonates across this part of thevalley. Note low CI concentration across MIIIIOOICt aquifer.MSL—mean sea leveL

-Jto

50

450-

400-

170

155

-140

- 125

- 110

-95

_____________

5 10 15 2Omi

5 0 5 t5


25 3OIan


Chemical and isotopic indicawrs ofgroundwater evolution

Bleuer, NIC. Melbono, W.N. 31w., Wi., and Bums, T.M.,1991. Aquikr systems of the hatted Mation-Mahomcttrunk valley (Lafayette bedrock saucy system) of Indiana. in Meihorn, W.N., and Kenipon, JR. au., Geology and Hyttugeotogy of the Teaya-Mahomet bedrockvalley systems: Geological Society of America SpecialPwtr 258, p. 19-39-

Bushy. EL, Phanaic,, Lit, La. LW. and Hanshaw, B.E.1991, Geochemical Evolution of Waler in the Maliam Aquifer in Pans of Montana. South Dakan, andWyoming: itS. Geological Survey Professional Papes1273-F. 89p.

Cantons, DA, 2004,A Sluily of (he Hydrologic Charaaeristics of the Mtotnet Wiley Aquifer through the Useof Dissolved Helium and 111gb Reaolutioe GeophysicalIkoflling 94.5. thesisi: Normal, illinois, Illinois StateUnàts*sc Dep.rsment of Geogsaphy-Geology, 64p.

Chebotastv Ii.. 1955. Mezamcqrtism of ssnnl waler inthe can of weathering: Geochimica a CosmochimicsAcla,v.8,p.22-48.

Chit. L, and Fritz, P. (997, Eaviromnental Isotopes inHydiogeology: Boos Raton. New Yort Lewis Publisbon, 32$ p.

Coleman, Dii. 1976. Isotopic Oaractnmndoa of illinoisNannI Ga, [PhD. dlsntatioml Urbana-Osaropaign,illinois, University of Illinois, Depailmeat of Geology.1751),

Coleman, DD., Liu, L.C, and Riley, Ic. 1988, Microbialmetha,e is the shallow Palecroic sediments and glacialdeposits of illrno.s, USA: Chemical Geology, v. it,p.23—40, doi: I0.1016’0009-2541(88$0103-9

Coleman, fl.fl., flu, CL, Hackley, tC., anti Benson, Li,1993, Identification of landfill methane using carbonand hydrogen isotope analysis, in Proceedings of 16thhitennalicasal Madison Waste Conference, Municipaland Industrial Waste: Madison, Wisconsin. Deparnisentof Engineering Professional Development. Universityof Wisconsin—Madison, p. 303—314.

Coleman, Mt., Shepard, Ti,, Durham. 1.1. Rouse, LE, andMoore, OR., 1982, Reduction of water with zinc forhydrogen isotope analysis: Analytical Chemistry, v.54,p. 993-995, doi: l03fy2llaclYY243a035.

Cssllany, 5., 1966, Vields of Wails in Pennsylvanian andMississippian Rocks in Illinois: Illinois State WaterSurvey Report of Investigation 55,43 p.

C,allany, S., and Walton, W.C,, 1963. Yields of ShallowDolomite Walls in Notihan ntis’s’. illinois StateWater Survey Report of Investigation 46.43 p.

Curry, Bit aid Foilmer. LR, 1992, The last irdaglacialglacial transition in illinois: (23-23 a in Clark, RU.,and Lea, P.1), ada, The La Inlerglacial Transition inNails America Geological Society of America SpecialPaper 270. p. 7148.

Dean, LA., 1992, l.age’s Hanttook of Chemistry (14thed New York, MeGaw-Ibul.

Dixssn, IS. Ha, Lt, Senkayl. At, and Egastaira, K.,1982, Miaesaiogial ptopatn of lignite e.abxdasasthey rein to mine spoil redaaaatiee. Chapa to. inKittich, it, Fanning, fl.S., and Noun, L. ada, AcidSulfate Wesheting: Proceedings of the Soil ScienceSociety of America Meeting. 5—IC August 1979: SoilScience Society of America Special Publication 10.p. 169—192.

Ebats, SM., and Geosge, LL. 2000, Regional GroundWater flow and Geochemistry in the MidwesternBasins and Arches Aquifer System in Pats of Indiana,Ohio. Michigan and Illinois: U.S. Geological SurveyProfessional Paper 1423-C. (02 p.

Epstein. &, and Mayeda, T.. 1953. Variation of O contern of waters from natural sources: Geochimka ctCosmoclsimica Ada, v. 4, p. 213—224. dci: l0.tOt6I0016-7037(53)90051-9.

611th. 32, 1970, Geoimdwaa Availability in Fad County:Illinois Stale Waler Sm-ny Circular 97.óóp

Goldhaber, M.B.. and Kaplan, lit. 1974, The sedimentarysulfur cycle, is. Goldberg, ED.. at, The Seas, Wlume5: New York, W,Iey-lnlesscience. p.569-655.

Goldhaber, Mit, and Kaplan, LR., 1980, Mechanisms ofsulfur incorporation and isotope fractionation dir’tog early diagenesis in sediments of the Gulf ofCalifornia: Macinc Chemistry, v. 9. p. 95-143. dci:lO.10t610304-4203(80)9c063-8.

Grinstey, DA, 1996. Suatignphy. Magnetic Susceptibility, and Mineralogy of l.oess—Paleosot Sequences inSouthwestern Illinois and Eastern Missouri [Phil dissestatioul: Urbana-Champaign. illinois, University ofIllinois, 317 p.

Gsossxann, EL Coffman, BK., Flier, iS, and Wada. It.1989, Bacterial production of methane and its inulsaonce on groundwater dsemistsy in east-central Texasuiftss: Geology, v. 17. p. 495—499, dot 10.1 t3G’0091-7613(1989)017-c0495:BPOMAI>2.3CO;l

Hackley, ICC.. 20(Y), A Claenical and Isotopic lnvestigatiooof die Gtoundwaa in the Mabosnet Bedrock ValleyAquifer: Age, Recharge and Geochemical Evolution ofthe Groundwater [Phil thesisl: Urbana-Champaign,Illinois, University of Illinois, 152 p.

Hackney, ICC., and Anderson. IF.. 1986, Sulfur isotopicvarialirms in low-sulfur coals (ruin the Rocky Mom.lain sqion Geochimica a Cotmod.imica Acts, v. 50,p. l703—1713.doi: l0.1016100l6-7037(86)90132-8.

Hackley, ICC.. fits, CL and Coleman, ftD., (992, “C dating of groundwater containing microbial C11: Radiocabon, v. 34, no.3, p. 686-695.

Hackley, ICC, fits, CL. and Coleman, Dii. 1996. EnvirastaI isotope dsasisrica of landfill lsntsand pact: Grotsvi Wa, v. 34, p. 827-836, dot:10.1 Il1iI.l745.6584.19961W2077t

Hackney. ICC., Liii. CL, and Trasnoc 1).. 1999. Isotopicidentification of the sotlee of methane in subsurfacesediments of an area smroimdnd by waste disposalfacilities: Applied Geoctsesnimy. v. 14, p. 119—131.dci: tO.10161S0883-2927(9800036-5.

Hamdan, AS.. 1976, Gno.ni-WaIer Hydrology of IroquoisCo.mty I M.S. thesis): Urbana-Champaign. Illinois,University of Illinois, Geology Depatent, 72p.

Hansel, AJC, and Johnson, WIt. (996, Wadron andMason G,otsps: Lithostmsigraphic Reclassilication ofDeposits of the Wisconsin Episode. Lake MichiganLobe Area: Illinois State Geological Survey Bulletin 104, 116p.

Hem, 11)., 1992, Study and Interpretation of the ChemicalCharacteristics of Natural Water (3rd tat): U5 Geological Survey Water-Supply Paper 2254.264 p.

Hereog. B.L. Wilson, S.D.. Larson. DR., Smith, EC.,Larson, T.IL, and Gerenslate, M.L (995. Hydrogeology and Groundwater Availability in SouthwestMcLean and Southeast Tawdli Counties: Past LAquifer Qjaractesizndms Illinois Stat GeologicalSurvey and Illinois Stat Wan Survey CooperativeGrotmdwater Report 17.70 p.

Hotm. T.R. 1995. Grosard-Wan Qeality in the MahometAquifer. McLean, Logan, aid Tarewell Counties: Winois State Water Survey Co.ateaa Repott 579. illinoisDepanmeneofNartnl Resomoes, 42 p.

Horberg. 1., 1945. A major buried ‘talky in eats-centralIllinois sad its regional relajiurships: The Journal ofGeelogy,v. 53, no.5, p.

Ilotbag, L, 1953, F$eiatueme Deposiss below she Wsscensin Drift in Ncailaeaatrn Illinois: Illinois StateGeological Stsnty Report of Investigadons 165,61 p.

Illinois Stale Water Plan list Font, 1997, The MahonaeiBedrock Valley Aquifer System Knowledge Needs fora Vital Resource Ustarta-Cbasnp.ign. Illinois, WaterResources Center UIUC-WRC-97-021, Special Repo.t21. 49p

Kaplan, LR., 1983, Stable isotopes of tutf,r, nitrogen anddeutesium in re marine asvitoe,nessts, in Stableisotopes in Sedimentary Geology: Society of Economic Paleontologists sad Mineralogists, Short CoursetO. p. 2-1—2-tOt

Kelly. Wit, 2005. Arsenic in Groundwater in Central illi’nois: Champaign, Illinois, Winois Slate Water SurveyReport IEM 2005-02, 2p.

Kelly, W,R., and Wstsoo, SD.. 2003. Temporal changes inshallow groundwaser quality in northeastern Illinois.in Illinois Grcamdwaa Ctmscatium I’Ynceedings 2003:Carbondale, Illinois, Southern Winnie University,19 p. bttpi/ordasiuc.tdungc/proceedings/lndethtntl(September 2(W).

Kem1rtots, LP,, Morse, Wi., and Vssodcy. AR, 1982, Hydrogeologic Evaluation of Sand and Gravel Aquifess forMunicipal Groundwater Supplies in East-Central illinois: Illinois Stat Geological Survey and Illinois State

Water Survey Cooperative Groundwater Report 8,59p.

Kenaptots, JR. Johnson. W.H., Heigold. PC. and Castwright, K.. 1991. Mahomet bedrock valley in eastcentral Illinois: Topography, glacial drift strati graphy.

hydrogeelogy. in Melbern, Wit. sad Kemgtnt.,32.. eda, Geology and Hydrogeotogy of the TeaysMahomet Bedrock Valley Systems: Geological Societyof Asneaica Special Paper 258,p. 91-124.

Kirk, Mit. Helm, ‘ER,, Past 3., 3m. Q.. Sanford, R.A,Rsuke, B.W_ and Bethke, Ott, 2004. Bacterial sulfate reduction limits namral arsenic contaminationin groundwater: Geology, v. 32. p. 953—956, doi:10.1 130/G2m42.l.

Mass, fit, 1984. Methane from anaerobic fesinentadon: Science, v.223, p. 1021—1028, dci: 10,11261soonce223.4640102L

Kolata, Kit, Deany, RE, Devera, IA.. Hansel, AK,Jnsbecm, RI. [asemi, Z., McGany, CS.. Nelson,Wi.. Notby. RD., Tteworgy, C.G, and Weibet, DY..2005, Bedrock Geology of illinois: mint Slate Geological Survey, Illinois Map 14, sale l:5o00

KrasskoçL KS. 1961, Introductios to Genchemimy Internaticmal Series in the Earth aid Planerary Sciences:New Yak. McGqaw.Hill Boot Co.?2tp.

Krisrjansson, iN., Schoenheit, P.. and maria. RN., 1982.Different K, values for hydrogen of methsaogenicand nslfa*e-sed.acing baaesia An esptanaiion for theapprnent inlaibilioe of methanogessesis by sulfate:Archives of Micsobiology. v. 131. p. 278—282, dottO. lOOl/BF00405893.

flu, Ct. and Coleman, D.fl. 1981, Illinois State Geological Survey radiocasbon dales ‘lit Radiocarbon, v. 23,p. 352—383.

flu, C-L, Riley, 1CM., and Coleman, nD., 1986, illinoisState Geological Survey radiocarbon dates IX Radio-carton, v. 28, p. 110—131

Martens, CS., and Barter, LA.. 1974, Methane producdot, in the interstitial waters of sulfate-depletedmarine sediments: Science, v.185, p. 1167—1169, dci:lO.Il2fliscience.l85.4t57.I 167.

McMahon, PB.. and Chnpelle, Fit. 1991. Microbial production of organic acids in aquitard sediments andits role in aquifer geochemistry: Nature, v. 349,p.233-235.

Mcenrs, W. F., 1960, Glacial-Drift Gas in Illinois: illinoisState Geological Survey Circular 29), 58 p.

Melhern,WK, and Kempton, iF, 1991, Theliays System:A sumsnay, its Melborn, Wfl and Neaspmn 12,, ads.Geology and Hydrology

Ilackley et it

Ostlund, ItO., and Doisey. HG.. 1977, Rapid electrolytic

( endcbmeat and hydrogen gas proportional counting

of nidum, in Low-Radioactivity Measurements andApplications, floceedings of the International Cutsfrance on Low-Rathoactivily Measarenirasts andApplications, 6-10 Oa 1973. The High Tatras,Datd,oslonkia &adslan. Slovenske PedagogickeNakiait’atvo, p.55—00.

Panno, SN., Hackley. ICC, Cmwsight, IC, and [its, C-L,1994, Hydsochenilstry of she Mahomet bedrock valleyaquifer, east-cenni Illinois: Indicators of recharge medground-water flow: Ground Waxes, v. 32. p. 591-604.del: 10.11 Ilrj.t745-4584.I994.1h00895.x.

Pilon, RE., d Howard. ICW.F., 1987, Ca,nminaounof subroifree wits by road do-icing chemicals:Water Pollution Reaemch So.nnal of Canada, v. 22.p. 157—171.

Numnaa. Ni.. Busby, I.E., Lee, LW., and Hanshaw, SB.,1990, Geochemical modeling of the Madison aquiferin pats of Montana. Wyoming. and South Dakota:Water Resources Research. v.26, p. 198 t—2014.

Ro.&ap, 0.5., and Wilson, S.D., 2001. The Impact ofEmergency Pumpage at the Decatur Well Fields onthe Mahomet Aqitifec Model Review and Reconwnaidadoas: Illinois State Water Survey, Contract Report2001—I I, 68p.

Sanderson, E.W., 1971, Groundwater Availability in PlaitCounty illinois State Water Survey Circular 1(17.83 p.

Schoeller, H.. 1959. Add Zone Hydrology Recent Develop‘news: Pads, UNESCO. 125 p.

Shaver, LB., and Puse S.W., 2005, Hydraulic banias inPloisatne buried-valley aqsnfezs: Ground v.p.21—28, dot 10.1! ltFj.l745-6584.l992.thO1.x.

Sofley. W.B., Place, R.It, and Perlman. WA.. 1998, Esi.i.natal Use ofWatrin the United Stats in 1995: U.S.Geelogical Survey Circular 1200.71 p.

Slep&saon, O.k. 1967, Hythogeology of Glacial Depositsof the Mahoniet Bedrock Valley in East.Centx-aIIllinois: Illinois Star Geology Survey Circular 409,St p.

Stumsn, W.. and Morgan. ii.. 1981. Aquatic Chemistry:An Issboduction Emphasising Chemical Equilibria is,

Natural Waters: New York, John Wiley & Sons Inc.,ThOp.

Ueda. A., and Krouae, KR., 1986, Direct cunvession ofsulpbide and sulphate minerals to SO, for isotopeanalyses: Geod.enneal Jotunal, v. 20, p. 209-212.

U.S. Geological Svey (USGS). 1999., The Quality of OttNation’s a—Nwdenu and PeaticideE US. Geological Survey CIrcular 1225, 82p.

U.S. Geological Survey (USGS). 19991.. Ground-na studies in Illinois, l.vsgagovIprtlgwstatied(September 2009).

Van Stesnpvoat DR., Hendry, M.L, Schoensu, Si., andKrouse, ILL, 1994, Sources and dynamics of sulfitein weathered dli, wean glaciated plaint of NoethAmaica Ciaeminl Geology. v. Ill, p. 35-56, dotlO.l0l&0009-2541(94)900S1-7.

Wanemam,, T.W.. and O’Neil, IS., 1993. A simple andinespeasive method of bydrogea isotope and wanalyses of minerals and rocks based on zinc reagentChemical Geology, V. 103, p. 227-234, dot 10.101610009-2541(93$0303’Z.

Visocky. AS., and Schitht, Ri., L969. Groundwater Resources of the Boded Malaomet BeaveR Valley; Illinois State Water Survey Report of Investigations 62.sip. -

Wagnes, OP., Fanning. 0.5., Foss, I.E., Patterson, ItS.,arid Sno. PA., 1982, Morphological anti minesalogical Peanuts rebeed to sulfide oxidation under naturaland distuatsed land surfaces In Maryland. Chapter?. fit

Acid Sulfate ‘tWatheting: lkoeeedings of the Soil Sdence Society of America Meeting, 5-10 August 197tSoil Science Society of Amaica Special PtthlicadonlO,p. 109—lid.

Warner, ICL., 2001. ArsenIc in glacial drift apsifess and theimplication for dsimldng wan—tower Illinois Rivurbasin: Ground Water. v. 39. no. 3. p. 433-442, dot10.111 lij.1745—6384.2t%)l.1ts02327.x.

Warner, ICL, and Arnold, Ti, 2005, Framework forRegional Synthesis of Water-Quality Data for theGlacial Aquifer System in the United States: US.Geological Survey Scientific Investigations Repair2005-5223, 6p.

Warner. K.L, Minis, A., Sc, and Ansold, T.L. 2003, Arsenicin Illinois Groiaad Wster—Conununity and PrivateSupplies: 115. GeologIcal Survey Water-Resourceslnve.sligalirms Report 03-4103, l2p.

Wbisicr. Mi.. Faber, a. Schoell, 14., 1986. Biogauc methane formation in marine and freirwater environments:CO1 reduction n fommn-.se(ope evidence:Geodliala a Coonodsisnia A, v. 30, p. 693-799.

Wigley. T.M.L Phaimin LN., and Pearson, El., lr_1978, Mass umnafer and carbon isotope evolution innatural waler systems: Geoduimia at Coirnochimira

Acts, v.42, p. 1117—1139. dot: l0.l0l6l6-7037qs$0l0g-4

Willnaan, RB., Atheston, li., Buschba*, T.C., CoflInsoo,C., Frye. IC, Hopkins, ME, [iaeb.ck, l.A., andSimon. LA_. 1975, Hantisook of illinois SuasigraphyIllinois State Geological Survey Bulletin 95. 26lp.

Wilaoa. &D., Roadeap, CS., Hazog. Hi., [arson, DR..and Winstanley. 0., 1998, Hydsogeotogy and Ground.Wars Anilahuity in Southwest McLean and Southeastflzewdl Counties, Past 2: Aquifer Modeling and FinalReport Illinois State Waler Survey and Illinois StateGeological Survey Cooperative Ground-Water Re.poet 19. I38 p.

Woiles, D.M., 1974. Public Groundwater StqtplIea in FordCounty: Illinois Slate Water Survey. Bulletin 60-8,ISWS-74-BtJL6O(8), 19 p.

Wood, W.W., 1981. Guidelines for collection and fieldanalysis of ground-water samples for selected unstable aaadtnss, Oqa. 02, it lèdatiques of WatrResources Investigations of the U.S. GeologicalSurvey, Book I: Washington, 24p.

Yanagitawa. F.. and Sakai, It, 1983. Thermal decotnporilion of bamusn sijifat—vanadlun, pentaoxide-silicnglass nissan preparation of sulfur dioxide in sulfir isotope saab measurements: Analytical Chemistry.v.55, p. 985—987. dot lO.10211ae00257a046.

Mnssnwr Raxvw 29 Oaonia 2(538REVWn Ma,aac.n Rauvw 28 Mgi tsXI9lhtn,.sacawr Arcapsars 2 lut.v 2009

P&aediaisc USA

1066 GeoLogical Society of America Bulletin, JulylAugust 2010

ATTACHMENT 2

Geological Drawings G2 and G3

APPROXIMAIS EXISNINO PERMITTED CLINTON LANDFLLL NO.3WASTE BOUNDARY

OWAWNO MOV F] FAA P00 50N TWA. SLRYCES. NCURAWSC SO- P—XSI, DXIEO 2—25—CS.

3X S XIS

CLINTON LANDFILL NO.3 CHEMICAL WASTE UNITPRGA. NO.:

DEvvrrr COUNTY, ILUNOIS

____

OLSAGNED I;

DRAWN WI]

flt<EO WI]

WPPROSED 2Y

SiA

Z2O

IO5:

55:0

2PM

D©

lPf4fl2C7

1t5:4

All atz C C C 0 z

.VA

1IO

N(FW

•SEllS

I.:L

EV

AT

ON

(FEETAIDV

E MDL)

[iii

\cj

•.—

JF\

%i N

/

N /

0 [1

(‘H Iz N N

H’/

N

H: -i1

N k

/

——

—I—

ajy L-

—H—

I—

: ii !.I-

!1iD

V1.

LI

,t—

’‘$

;:I&

,II

LII

.1j

( K

F

il r 1: r o<

,0 o

-r

o oP

tot

0Z

w0

-10

m-c

a z—

nU)

Z)‘

_r

go 14

-J -j

S [I

Tn-C

,

ft•l1

0

-J

:2

ii o z 2 0 2

b

ELEV

ATI

ON

(FEE

TA

lON

EA

OL)

r

jtii

bL

hiS

•I

•I

:i

H 2

z C

1,

F’.

At

Al

C’

C

>2

VER

TID

&.

Sq

xx >

rS

NN

•2

HC1

00

otO

XC

•tO

X

0w

02

otC

C

S

!55 O

w

ELEV

ATI

DN

(rif

T)V

E

S Ir It C IT’ z 0

IL

a

AHACHMENT 3

Groundwater Impact AssessmentInput Parameter Tables

TABLE 812.316-4INPUT VALUES FOR MODEL - UPPER RADNOR TILL SAND

01) m’meters

2) mg/I = milligrams per liter

3) m2Ja = meters squared per year

4) mla = meters per year

5) cm3lg = centimeters cubed per gram

6) cra/g’ centimeters per cubic gram

7) a year

TlProjectsi9l-JI8 CLIlPermit ApplicationsCL1 #3 Initial BOL Application Lag 2OO5-O7OlGroundwarerCLI#3 Modeling Input Parameters

3

Clinton jLrn!fl!J$Q.,3

File Information Baseline Model Input File: LKWBJN - -

Baseline Output File: LKWB.OUInitial Source Concentration I mg/I

2

LnwttIb*aq Conthtson Infinitetop floñ4j Constant Source

LAYER I Nyd1o4y$cThspersionEoefflcient I 58EM2 rnia

Dompacted Clay Effective PoroSity 0 3-. 3

InpuiParameters Dtnsit - L96M96

Number4.th1ycra 4VertipL.VajQ - 3S1S&03

LSYERZ 1598Aqinfer 0.35 —.

IEiput Parameters Délisity 1 9 glen?flitkness 6096 m)jiimber oj$ablayers 13VenVfcity(Fha) 3 515E-03 rn/a

Times & Distances tmit to ut -- 5, 10, I, , 145

Veil iite (t9tQ)- 61 056 in

twatlon Laplace Transfbrm 7 20, 0 2aameters

D

0.01 scp

4-.

4. O.tU)

Notes:

revisedrrls

‘,.

I.n

\d

0

—.rnrC

.

11.0

aN

Or

S’

140

-

or

20

.3“SC

StodL

____

an—

S

0.

zC04-CC.;

,=

==

II

==

=—

==

=I

=I

I—

==

=C

—Ct

==

—=

=

jH

j’4riH

srj

j’]sii

..

C

‘ig0

.en

enen

en

4.

900o

‘ecc

9cc

00

oc9cc

-cc

9

-u

2r

.!_

0C

C!

-nao

dd

dd

hen

enen

en

c

cii,,

iI

-

j00

——

00>

.v

-05>

,

0—

5-

C‘-

-.C

Co

C—

COg

go

go

go

-c

g‘

hU

H-

H-

8g

pQ

00

0

.>

>I—

?>

:—

->

->

t°h

3L

9.2

EN

N.

4-).

I).

sg

•caS

c.

S-t

tc

Sct

t.

St

tt

:1JJI

-II5%4Sc-)SOS

.’

0’U‘S

C—

.2—-—

0St

Id

.sR

,c1.

t

0I04.)SItCO4-C’

: vu -;aea-- - ——

LAYERS Vertical Dispersion Coefficient 12.84 rn2faAquifer Effective Porosity 0.3

input Parameters Adsorption Coefficient 0 cm3/gDensity 1-9 Wan3Thickness 0.8543 rnNumber of Sublayers 3

-

Horizontal Disetsxon Coefficient 64 08 m2/aHorizontal t)arty.Vtloclty 2 099 rn/aVcrticalDarcyVelbcity -

- - - Wirunes Times tórSinrnl&ion I

- - 5,10,15, 145 -

-

[hstances Lateral Distances 47434 481 96 489.58, 497 2SG4 82integration Talbot - 7, 11,6, FParameters Gauss Normal

TABLE 812316-5

INPUT VALIWS FOR MODEL - L0wEaRADNOR TILL SANDn41i.N43

Notes:

1) mrneters

2) mg/i = milligranis per liter

3) m2/a meters squared per year

4) rn/a = meters per year

5) cm3lg = centimeters cubed per gram

6) cmlg3 = cenhiftëtëiit per ëubic gram7) a year

T:ProjrcrsWJ-J 18 CLJkPermi ApplirohonsCL1 #3 J&tni SQL Appliralian Log 7005-O7OtGrtna,dwweriCLiJ3 Modrhng )ipit Paromr;er, rrwisrd,Is

U)

c

FC

—o

.to

40

U-

O,,

tO

L

c22

-

C2.Os.

I

2o°.

lo”

p.——

;“{

.0

•

•3tR

—03

‘?;ov__)t___,

0Q

”o

C

n=

=======

-=—

—=

•t

==

====

I- =

OS

tflat.’

[E

s1

4W

IP:iH

NIIH

Na

WEij

—

*iIC)

n

“R

9oc

09

ac

0e

9ac

ae9

-c:2

ac

oo

‘C

:10

:%]4Fvi-

1

:c3’—

——

—L

.C

-

—.

0—

V—

VV

0

--

-

,c0

,•

Lrg

F0

)C

’C

CC

Csa

“C

CC0o

C

ll1flflE

iiifliA

iiHJflA

flhiiflillN

hiflill

•1

It1IUIC

t,l’-

2i

r <-4’-- --,— —- - c

-

LAYER 5 Vertical Dispersion Coefficient 0.526 m2IaAquifer Effeclive Porosity 0.4

Input Parameters Adsorption Coefficient 0 crn3/g

Den,sity 1.9 g/ctn31ijckrtess 1.042 mNiñiber of Süblayeis 3Horizontat Dispersion Coefficient 2.505 -

- rn2/aHorizontal Darcy Velocity 0.1018 - ni/aVertical Darcy Velocity 0 mla

fimesDistances tñes Ir Simulation 1 5 10, 15, , 145 a)astances LatenilXslances 559 57, 567 19 57481,58243, 59005 mnteglaton Talbot 7,1I,o1Paraneters - auss Nwai- ----

-

1) m meters

2) mg/I = milligrams per liter

3) m2Ia meters squared per year


5) cm3/g = centimeters cubed per gram

6) cm/g3 = centimeters per cubic gram

7) a year

TABLE 812.316-6INPUT VALUES FOR MODEL - ORGANIC SOIL

Clinton Landfill No.3

Notes:

T:ttrojectst9l- 118 CLIWermil ApplicaflonskCLl $43 Initial BOL Application Log 21H15-Q7otGroundwrnerlCLl#3 Modeling lnprn Parameter, revüecLxli

Si”

-t-Q

.—3?’

Ito—

cS

’I

‘ne

6\>

)//e’

Cl)

FC

C.,—

,—

UI.Fz

ir

—=

——

==

=—

==

==

==

==

==

==

=

!IIt0

00

00

00

o‘

000

00

)—

%t

0.

C)

I—

J—

.—

——

—

j—

——

——

——

&,

CC

CC

U.0

6)6)

4)4)

6)

H3

3y

F-’

4)4)

4)4)

4)U

U>4

00

00

00

0C

C)C)

C)C)

C)C)

•g

C—

..—0

04

.—S

.-.

.

CC

04)

04)

04)

04)

0U

04)

0..

4)4

)0

4..4w

4w4w

C.)C)

—U

.?

rp4

.4

Q.4

-.E

ts3

rt

t-o

t

.

—,,_>

,—

SC

44g

-

S0

z—

-

Notes: -

1) mmetaS

2) thg/liiilliat&ptr liter

3) m2fa meters sqijared per year

TABLE 812.316-7INPUT VALUES FOR MODEL - MAIIOMET SAND

Clinton Landfill No.3

LAYER 8 Hydrodynamic Dispersion Coefficient 0.0158 m2faVaridalia Till Effective Porosity 0.286

Input Parameters Density 1.9 g/cm3Thickness 15.24 in

tiiu*r of Sublayers 3Vjj1aWarcy Vtloczty (FluA) 3 51 5E-03 m2)a

LAYiI4 9 }I)rdrodynamic Dispersion Coefficient & 0315 m2faMahomet Sand Aquifer Efrctive Porosity 0 3

Input Parameters . 1.9 Wcm3)flpSss 30.48 in

--.

tunes - iaWWiThflon 5, 10, ft , 145 aDistances 56 393 m[ntegratiôn

Laplace Transform 7, 20 0 2Parameters


5) cm3/g = centimeters cubed per gram

6) cm/g3 = centimeters per cubic gram

7) a year

UFJP

)

1)

a

ATTACHMENT 4

Clinton Landfill No. 22009 Potentiometric Maps

(Deep Wells)

CAD DWC No9TIIaIEnI Fup,mrr NO Qfl22fl

200’ 100’ 0—

1 20O’

200 400’

LEGLNDG43D® EXISTING MONITORING WELL

667.89 POTENTIOMETRIC ELEVATION

— 662 — POTENTIOMETRIC CONTOUR LINE

NOTES:L WATER LEVEL MEASUREMENTS

ON JANUARY 7, 2009.

2. P500 WAS NOT UTILIZED TO CONSTRUCTPOTUNTIOMETRIC SURFACE.

000In

a

+

00tflTn

a

+

000

a

+

00Lfl

a

+

.+ E 6500

® G34D674.07

E 6500

RSODQ672.95

+ + C43D

WERE COLLECTED

+ +

GS3D661.85r

t

Z

t

+ E 7000

6510- 66174

4)o

6460-66918 R400

670.91

000tO

a

+

J’DC TechnicalServices, Inc.

aFIGURE 6

2009 1ST QUARTER POTENTIOMETRIC

CONTOURS — DEEP WELLS

CLINTON LANDFILL NO. 2CLINTON, ILLINOIS

PROJECT NO. 91—118Peoria, IUinoii

CAD OWC NO:911181602 FMP1flF Nfl Qfl7fl flATrLIaLrQCb,. /tfl,..

LEGEND643D® EXISTING MONITORING WELL


‘—662—--’ POTENTIOMETRIC CONTOUR LINE

200’ 100’ 0 200’ 400’I —

1 “=200’

+ E 6500

RSOD®’67506

+ + + +

C53D662.98

I;

NOTES:1. WATER LEVEL MEASUREMENTS WERE COLLECTED

ON MAY 27, 2009.

2. R500 WAS NOT UTILIZED TO CONSTRUCTPOTENTIOMETRIC SURFACE.

.+ £ 6500

E 7000

® C34D674.26

+8

I..

0

C‘U

0C

U

0’

0

+ I;

+

000I,

a

+

00a)p3

a

+

000

+ E 7500+

000Inaz

00LU*

a

+ + +

PVC technicalServices, Inc.

aPeoria. Illinois

FIGURE 72009 2ND QUARTER POTENTIOMETRIC


CLINTON LANDFILL NO. 2CLINTON. ILLINOIS

PROJECT NO. 91—118

flJJ fl.SU’ 10-

200 100’ 0

1 “200’

200’ 400’

LEGEND0430 ® EXISTING MONITORING WELL


— 662— POTENTIOMETRIC CONTOUR LINE

NOTES:1. WATER LEVEL MEASUREMENTS WERE COLLECTED

ON JULY 20, 2009

2. P500 NOT UTILIZED TO CONSTRUCTPOTENTIOMETRIC SURFACE.

E 6500R550658.28

P500674.52

+ + + +

0530662.31

+ E 6500

7/

r

C520!662.33

+

C

I..

CC

a

0

3C2C

0S

V

3C,

aa

+ ±E7000

G51066109

G460669.52

+ +

R400671.46

+

• “3-N

+

± E 7500

0 0 0 0 00 0 0 0 00 a) 0 U) 0Tn Tn * U)z z z z z

+ +

PVC TechnicalServices, Inc.

+

FIGURE 8

aPeoria, Illinois

2009 3RD QUARTER POTENTIOMETRIC


CLINTON LANDFILL NO. 2CLINTON, ILLINOIS

PROJECT NO. 91—NB

LEGENDG43D ® EXISTING MONITORING WELL


—662-— POTENTIOMETRIC CONTOUR UNE

NOTES1. WATER LEVEL MEASUREMENTS WERE COLLECTED

ON OCTOBER 5. 2009.

2. R5OD WAS NOT UTILIZED TO CONSTRUCTPOTENTIOMETRIC SURFACE

200’ 100’ 0 200’ 400—

1 “=200’

+ E 6500R55D65731

RSODQ67444

+ + + +

G530662.46

+ E 6500

I •

S

‘4

0.

0

U

lBCiS0

0

C

8

0

139

2

13

++ E 7000

0510661.64

*7CiJ G34D674.11

- 669S5 .

-

+

+

+

+ C 7500

0 0 0 0 00 C) 0 0 00 LI) 0 a) 0to to 1)z z z z a

+ + +

PDC TechnicalServices, Inc.

aFIGURE 9

2009 4TH QUARTER POTENTIOMETRIC


CLINTON LANDFILL NO. 2CLINTON. ILLINOIS

PROJECT NO. 91—118Peoria, Iflinois

A.

ATFACHMENT 5

Technical Review:Proposed Chemical Waste Unit

at the Clinton Landfill No. 3Dewitt County, Illinois

Technical Review:

Proposed Chemical Waste Unit at theClinton Landfill No. 3Dewitt County, Illinois

By

Craig H. Benson, PhD, PEMadison, WI 53706

27 September 2009

1. INTRODUCTION

This report describes a technical review of the proposed Chemical Waste Unit (CWU) at

Clinton Landfill No. 3 in Dewitt County, Illinois. The proposed CWU would accept non-

hazardous industrial wastes, including wastes containing up to 500 ppm of PCBs.

Because PCB wastes would be disposed, the proposed CWU must comply with

regulations imposed by the Toxic Substances Control Act (TSCA). Additionally, disposal

of other non-hazardous industrial wastes requires that the landfill meet the requirements

of Subtitle D of the Resource Conservation and Recovery Act (RCRA) and any other

regulations specific to Illinois for non-hazardous solid waste disposal.

The review addressed the following issues: (i) whether the proposed CWU complies

with TSCA regulations, (ii) whether the proposed containment system will protect the

Mahomet Aquifer, (iii) whether the containment system will protect shallow ground water

units beneath the proposed CWU, and (iv) the long-term threat to the environment

imposed by the proposed CWU and whether the proposed CWU is protective of the

public health, welfare, and safety. The review was conducted using the documentation

contained within Volumes l-IV of the report entitled “Application to Develop and

Operated a Chemical Waste Unit Within the Permitted Clinton Landfill No. 3” as well as

the report entitled “Additional Information for the Chemical Waste Unit at the Clinton

Landfill No. 3.” Both reports were prepared on behalf of Clinton Landfill Inc. by Shaw

Environmental of St. Charles, Illinois.

This report consists of six sections, including this introduction (Section 1). Section 2

describes the TSCA regulations relevant to the containment systems for the proposed

CWU and an assessment of whether the proposed CWU complies with these regulations

[see (i) in preceding paragraph]. Sections 3-5 address each of the other three issues

cited in the preceding paragraph. Section 6 provides a conclusion.

2. TSCA AND RCRA REGULATIONS

The technical requirements for a TSCA landfill for disposal of PCBs and PCB Items are

contained in Subpart D (Storage and Disposal) as described in 40 CER 761.75

(Chemical Waste Landfills). These requirements can be segregated into siting

requirements, surface and ground water monitoring requirements, liner and leachate

collection system requirements, operations requirements, and facilities requirements.

I

Each of these requirements is described in the following subsections. The final

subsection compares the proposed CWU to these requirements.

2.1 TSCA Siting Requirements

The landfill must be sited so that the following conditions are met:

Siting in a geologic environment consisting of a thick and relatively impermeableclayey formation. If a natural geologic environment with a thick and relativelyimpermeable clayey layer does not exist, then the landfill should be sited on a soilhaving the following characteristics:

- In place soil thickness 4 ft or compacted soil liner thickness 3 ft.- Hydraulic conductivity less than i0’ cm/s.- Percent fines at least 30%.- Liquid limit at least 30 and plasticity index at least 15.

• Base of landfill shall be at least 50 ft above historic high ground water table.

• Ground water recharge areas should be avoided.

• Floodplains should be avoided. Structures for diversion shall be provided if thelandfill is within the 100-yr flood plain. Otherwise, diversion structures shall divertrunoff from at 24-hr 25-yr storm.

• The landfill area shall have low to moderate relief to minimize erosion and ensurestability.

2.2 Surface and Ground Water Monitoring

The surface and ground water monitoring programs must satisfy the following:

• Surface and ground water monitoring shall be conducted in adjacent water bearingunits. Monitoring systems and programs must include:

- Sampling of surface and ground waters prior to commencing landfill operations.- Designated surface water courses shall be sampled monthly during operations.- Designated surface water courses shall be sampled semi-annually after closure.- For relatively impermeable subsurface conditions, three ground water monitoring

wells shall be provided that are equi-spaced along the predominant axis of groundwater flow.

- Water samples will be analyzed for POB5, pH, specific conductance, andchlorinated organics.

2.3 Liner and Leachate Collection Systems

The landfill liner and leachate collection system must satisfy the following:

2

• Synthetic membrane liners shall be used if the hydrologic or geological conditionsrequire such a liner to provide a hydraulic conductivity at least equivalent to theclayey layers cited in Section 2.1. The synthetic liner must be at least 30-mil thickand be chemically compatible with PCBs.

• Leachate collection/monitoring system shall be installed and monitored monthly forquantity and chemical characteristics of the leachate. The leachate collectionsystem can be one of the following three systems:

- Gravity flow drain field placed directly above the liner.- Gravity flow drain field and additional liner placed directly above the liner.- Suction lysimeter network.

2.4 Operations

The following operations conditions must be met:

• An operations plan shall be developed that describes operational issues, recordkeeping, surface water management, and waste burial information.

• Items shall be placed in the landfill in a manner that will prevent damage tocontainers or articles containing PCB items.

• Wastes incompatible with PCB5 and PCB items shall be segregated from PCB5.

• If the facility accepts liquid PCB wastes, the operations plan shall include proceduresto stabilize the liquid to a non-flowing form and determine if the concentration is lessthan 500 ppm.

• Ignitable wastes shall not be disposed in the landfill.

2.5 Supporting Facilities

The following supporting facilities and operations must be satisfied:

• A 6-foot barrier (wall, fence, etc.) shall be place around the facility to presentunauthorized persons and animals from entering.

• Roads shall be maintained that are adequate to support operations and maintenancewithout safety or nuisance problems or hazardous conditions.

• The site shall be operated in a manner that prevents safety problems associated withspilled liquids or windblown materials.

3

2.6 Assessment of Proposed CWU at Clinton Landfill No. 3

The proposed CWU was compared to the technical requirements in TSCA that

are described in 40 CFR 761.75. A summary of the elements that were compared is

shown in Table 1. This comparison showed that the proposed CWU meets or exceeds

TSCA technical requirements in all cases. A summary of the comparison follows.

Siting. The proposed CWU will be constructed in a geological environment consisting

primarily of thick fine-grained soil layers that will greatly restrict movement of

contaminants that might emanate from the CWU. Separation between the base of the

CWU and the Mahomet aquifer greatly exceeds the required 50 ft minimum separation,

and the location is not within an Illinois regulated recharge area or the 100 yr flood plain.

The topography of the area has modest to low relief, which will minimize erosion and

promote stability.

Ground Water and Surface Water Monitoring. An extensive monitoring network is

planned that exceeds the requirements in TSCA. This system, coupled with theexisting

network for the other units on site, will provide adequate monitoring. The monitoring well

design standards planned for the site are consistent with Illinois requirements, which

exceed those stipulated in 40 CFR 761 -75(b). Sampling of the wells will occur on

regular intervals and will include all constituents required in 40 CFR 761.75(b). Surface

runoff will be sampled and analyzed in a manner consistent with 40 CFR 761.75.

Liner and Leachate Collection Systems. Given the thick fine-grained layers beneath

the proposed CWU, an engineered liner system is not required according to 40 CFR

761.75(b). Nevertheless, a highly redundant engineered liner system is proposed that

consists of three geomembranes (synthetic liners), a geosynthetic clay liner, a

compacted clay liner, and an internal drainage layer. This highly redundant system,

combined with the favorable geological environment, will effectively control migration of

contaminants from the proposed CWU. Field tests conducted on site as well as tests

and analyses conducted on similar soil by the Illinois State Geological Survey and the

University of Illinois at Urbana-Champaign have shown that the soil used for the

compacted clay liner can be compacted to low hydraulic conductivity (< i0 cmls) and is

an excellent barrier to contaminant transport. A leachate collection system is also

included that meets the criteria for both the ‘simple leachate collection system’ and

‘compound leachate collection system’ described in 40 CFR 761.75(b).

4

Operations. An operations plan has been proposed that deals with the management

and recordkeeping issues stipulated in 40 CFR 161.75(b). This plan also stipulates

methods for waste placement, segregation, stabilization, and monitoring of PCB

concentrations that are consistent with 40 CER 761.75(b).

Supporting Facilities. The proposed CWU includes provisions for security via fencing,

installation and maintenance of roads to ensure safe access, and training to ensure the

safety of personnel and others at the facility.

RCRA Compliance. The containment system for the proposed CWU has the same or

more robust engineering features than the adjacent municipal solid waste (MSW) landfill

that has been permitted under Illinois rules, which supersede those stipulated in RCRA.

Thus, the proposed CWU meets RCRA criteria as well as TSCA criteria.

3. PROTECTION OF THE MAHOMET AQUIFER

The Mahomet Aquifer is an outwash aquifer consisting of sands and gravels up to 150 ft

thick that rest on top of shale and sandstone bedrock. Ground water in this aquifer is a

water supply for the region and is the primary water source for the City of Clinton, IL and

nearby Weldon Springs. Because this regional aquifer is an important water supply,

protecting the aquifer from contamination is a necessity to protect the health, safety, and

welfare of the public.

Long-term protection of the Mahomet Aquifer is provided naturally by the overlying fine

grained soils in the Berry Clay and the Radnor Till. The silt and clay fractions of these

units and the stress imposed by the overlying overburden render these natural units

nearly impermeable, with hydraulic conductMties in the low 108 and io9 cm/s range.

Under such conditions, chemical diffusion becomes the predominant mechanism for

contaminant transport, which is ideal in terms of protecting underlying ground water.

When diffusion controls contaminant transport, the rate at which contaminants move and

their flux into surrounding units is at a minimum.

The liner system for the proposed CWU will provide additional redundant protection

above and beyond that provided naturally by the Berry Clay and the Radnor Till. The

liner system is more extensive than normally required at modern MSW landfills, and

5

includes internal redundancy exceeding that required for US hazardous waste landfills.

The base of the liner consists of a composite barrier comprised of 3 ft of compacted clay

overlain by a 60-mil geomembrane. A similar barrier system is commonly used for MSW

landfills in the US. The composite liner is overlain with a geocomposite drainage layer,

and then a three-layer sandwich consisting of a second geomembrane, a geosynthetic

clay liner (GCL), and third geomembrane. In addition, the geocomposite drainage layer

located between the upper three-layer liner sandwich and the lower composite liner will

provide a means to evaluate the efficacy of the lining systems during landfill operation

and after closure.

Two ground water impact analyses (GIA) were conducted to evaluate the potential for

contamination of ground water resources by contaminants released from the landfill. The

first GIA was conducted as part of the application for the adjacent MSW landfill rather

than specifically for the CWU. Consequently, the simulations considered only a single

composite liner (geomembrane over compacted clay liner) employed for the MSW

landfill rather than the highly redundant multiple liner for the proposed CWU. This

simplification added another level of conservatism to the GIA when applied to the

proposed CWU. The second GIA focused specifically on transport of PCBs from the

Cwl-J.

The first CIA consisted of a computer simulation to predict contaminant transport

through the landfill liner and the underlying geological formations. The simulation

assumed that Lateral transport in more permeable strata between the base of the Landfill

and the Mahomet Aquifer was negligible (e.g., all contaminants were directed downward

to the Mahomet Aquifer). The analysis also assumed that sorption was negligible. As a

result, the CIA was a conservative analysis (i.e., predicted higher concentrations than

would actually occur). The analysis showed that drinking water quality standards would

not be exceeded in the Mahomet Aquifer, even for the contaminant with the lowest

permissible concentration when the leachate concentration was at the highest

concentration theoretically possible (a very unlikely scenario). Accordingly, drinking

water quality standards for all other contaminants would not be exceeded. The

conclusion from this conservative analysis is equally valid for the MSW landfill and

proposed CWU, which will contain industrial waste with modest total contaminant

concentrations (e.g.. S 500 ppm for PCBs). Moreover, the first CIA is even more

6

conservative when applied to the proposed CWU because of the multiple liner system

that will be installed.

The second CIA considered PCB transport through a simplified version of the lining

system proposed for the CWU. This simplified lining system consisted solely of 3 ft of

compacted clay; the other barriers (geomembranes and CCL) in the proposed liner were

not included. The leachate concentration (aqueous concentration) was conservatively

assumed to equal the maximum permissible total concentration in the waste (500 ppm),

even though leachate data from analogous landfills containing PCBs indicated that

leachate (aqueous) concentrations are either very low (low ppb) or undetectable. The

Ieachate concentration was assumed to remain constant throughout the analysis and

sorption onto the organic carbon fraction was accounted for using conventional methods.

The model predictions showed that the PCBs were extremely immobile, and never

migrated through the entire thickness of the liner over a 1000-year period despite the

very conservative assumptions used in the analysis. In fact, concentrations even 1 ft

into liner were predicted to be orders of magnitude below detectable levels.

Both of these very conservative analyses illustrated that the liner design for the

proposed CWU will be protective of the Mahomet Aquifer.

4. PROTECTION OF SHALLOW GROUND WATER UNITS

Hydrogeological investigations conducted for the proposed CWU and other disposal

units at Clinton Landfill No. 3 identified three shallow ground water units between the

base of the landfill and the Mahomet Aquifer: the Upper Radnor Till Sand, the Lower

Radnor Till Sand, and the Organic Soil. These units are thin and moderately permeable.

None of these units is used as a major source of drinking water in the region.

The first CIA (for the adjacent MSW landfill and reviewed in Section 3 of this report)

evaluated whether ground water in these shallow units would be impacted by

contaminants released by the landfill. The simulation for the Upper Radnor Till Sand

assumed that Ieachate would be released directly to the sand beneath the landfill.

Simulations for the Lower Radnor Till Sand and the Organic Soil were similar to those

conducted for the Mahomet Aquifer. In all analyses, sorption to solids and lateral

7

transport in ground water units above the unit in question were ignored. As a result, the

analyses were conservative.

These analyses showed that the design proposed for the MSW landfill units is protective

of the Upper Radnor Till Sand, the Lower Radnor Till Sand, and the Organic Soil (i.e.,

concentrations of contaminants were below applicable ground water quality standards).

Because the proposed CWU will employ a more protective liner system and will contain

industrial wastes with modest concentrations, the conclusions from the GIA for the MSW

landfill pertaining to the shallow ground water units are valid for the proposed CWU.

That is, the proposed CWU will be protective of the shallow ground water units.

A similar conclusion can be drawn from the second GIA conducted specifically for PCB

transport from the CWU. Despite the conservative assumptions that were employed in

the analysis, PCBs did not migrate through the liner over a 1000-year period. Thus,

contamination of the shallow ground water units will not occur

5. LONG-TERM THREAT TO THE ENVIRONMENT AND PROTECTION OF PUBLICHEALTH, WELFARE, AND SAFETY

PCBs in the industrial waste to be contained in the proposed CWU will persist for a very

long time. Consequently, the proposed CWU will be a potential long-term threat to the

environment. However, the proposed CWU has been designed with several features

that mitigate this threat and ensure protection of public health, welfare, and safety.

These features include:

• siting on thick fine-grained geologic strata,

• a multiple layer liner employing three geomembranes, a geosynthetic clay liner, acompacted clay liner, and two levels of leachate collection and removal,

• waste monitoring and placement procedures to ensure that concentrations in thewaste are below maximum permissible limits and that the waste is placed in amanner that ensures protection and long-term stability of the containment system,

• filling and build out geometry that will ensure physical stability during operation andafter closure,

• capping with a final cover with a composite barrier layer and lateral drainage layerthat will limit percolation into the waste and consequent leachate generation afterclosure,

8

• a detailed construction quality assurance plan to ensure that all elements of theproposed CWU are constructed to specification,

• monitoring of shallow ground water units to provide an early detection system forpotential contamination of the Mahomet Aquifer, which serves as a major source ofdrinking water for local communities,

• monitoring of storm water runoff and air quality,

• fencing to prevent humans and animals from intruding on the site,

• a perpetual post closure monitoring and care program to ensure that the containmentand monitoring systems continue to function so long as the proposed CWU poses apotential risk to the environment, and

• financial assurance to ensure closure and post-closure monitoring/care of the landfillin perpetuity.

Contamination of ground water is the most significant potential threat posed by the

proposed CWU. This threat is negligible, as both GIAs illustrate that ground water

beneath the proposed CWU will be protected despite the use of very conservative

assumptions in the analysis. This level of containment is possible because of the

redundancy afforded by the multiple liner system, the secure geological environment,

and the relative immobility of PCBs in a matrix of soil and sediment such as that

anticipated in the proposed CWU.

Adequate protection of ground water will depend in part on the liner system remaining

intact during operation and after closure of the proposed CWU. This is a very likely

scenario, as the materials selected for the liner system are the most durable materials

currently available for containment of wastes, especially when deployed in multiple

layers in an environment with elevated stress that is nearly anoxic. The drainage layer

within the liner will also serve as a long-term sentinel of liner failure and excessive

discharge of contaminants. Thus, if a liner failure occurs, the failure would be detected

rapidly, permitting corrective action before a significant impact occurs to the surrounding

environment.

6. CONCLUSION

This review addressed whether the proposed CWU complies with TSCA and RCRA

regulations and ensures protection of the Mahomet Aquifer and shallow ground water

9

units beneath the proposed CWU. The review also provided a qualitative assessment

of the long-term threat to the environment and public health, welfare, and safety imposed

by the proposed CWU. The following conclusions are formed based on the review:

• the proposed CWU complies with and exceeds the technical requirements in TSCAfor disposal facilities,

• the geological setting, the redundant multiple liner system for the proposed CWU,and the final cover ensure isolation of the waste and protection of the MahometAquifer and shallow ground water units beneath the proposed CWU,

• the design of the containment system, the construction quality assurance program,and the monitoring plan for leachate, ground water, surlace water, and air willmitigate threats to the environment, and

• the perpetual post-closure care and monitoring program will ensure that the threatsto the environment are properly managed so long as the waste remains a potentialrisk, thereby ensuring protection of the public health, welfare, and safety.

10

Table 1. Proposed CWU design and operation relative to TSCA requirements.

Regulatory ICommentsRequirement

Evaluation

Siting

Landfill and major water supply aquiferGeological environment Satisfied separated by approximately 170 ft of fine

grained soils> 50 ft separation from Mahomet aquifer,which is primary water source in area. < 50 ft

50 ft. ground water separation Satisfied separation for Upper and Lower Radnorsands and for Organic Soil, but these arelocal ground water units and not water supply

Not located above sole source aquifer orGround water recharge Satisfied

regulated recharge area

Outside 100 yr flood plain, and approvedFlood plains Satisfied

storm water plan

Topography Satisfied Location in central IL has modest to low relief

Surface and Ground Water Monitoring

Site is already operating adjacent disposalunits that monitoring surrounding ground

Pre-operations Satisfiedwater and surface water Ground watermonitoring designed specifically for CWU.

There are no known designated surface waterDesignated water courses Satisfied courses at this time. Surface runoff will be

sampled and analyzed at storage basin.

The proposed ground water monitoring

Ground water monitoring wells Satisfied system greatly exceeds the required three-well network. The network includes 6 wellsimmediately down gradient of the CWU.

Monitoring well network will be sampledquarterly for pH, specific conductance, and

Water analysis Satisfied PCBs and annually for SVOCs and VOCs,including (but not limited to) chlorinatedcompounds.

Liner and Leachate Collection Systems

Because unit is located on thick fine-grainedsoils, a synthetic Liner is not needed.

Synthetic liner Satisfied However, CWU includes three syntheticliners, a geosynthetic day liner, and acompacted soil liner.

Leachate collection system SatisfiedProposed system meets the criteria stipulatedin 40 CFR 761.75(b).

Leachate samples will be collected andLeachate monitoring Satisfied analyzed monthly for pH, specific

conductance, PCBs, SVOCs, and VOCs

11

Table 1. Proposed CWU design and operation relative to TSCA requirements (con’t.).

CM.) IRequirement Comments

Satisfactory?

Operations

An operations plan is proposed thatOperations plan Satisfied addresses each of the issues in 40 CFR

761.75(b)The waste placement plan indicates PCB

Placement methods Satisfied wastes will be placed in a manner thatprevents damage to containers or PCB Items.The waste placement plan indicates PCB

Waste segregation Satisfied wastes will be segregated from otherincompatible wastes.

PCB concentration monitoring Satisfied Acceptance testing limits PCB concentrationto < 500 ppm.A solidification program near the active facehas been proposed. Liquid wastes to beLiquid PCB stabilization Satisfiedsolidified must have PCB concentration < 500ppm.

Supporting Facilities

The facility is fenced. The Inspection andBarrier/fence Satisfied Maintenance Plan ensures that the fence is

maintained.The Inspection and Maintenance Plan

Roads Satisfied ensures that the roads are maintained forsafe access.The Personal Training and Hazard PreventionSafe operations Satisfied programs provide for safe operations.

12

ATTACHMENT 6

Resume for Dr. Craig Benson

CRAIG H. BENSON, PHD, PE

Wisconsin Distinguished Professor 2218 Engineering Hall, 1415 Engineering DriveChairman Madison, Wisconsin 53706 USAGeological Engineering 2: tI (6) 262-7242, M: +1(608) 444-tXIO7University of Wisconsin-Madison chbenson4’wiscedu

EDUCATION

BSCE, Lehigh University - 1985MSE, University of Texas at Austin — 1987 (Civil Engineering, Geotechnicalfceoenvironmental)PhD, University of Texas at Austin— 1989 (Civil Engineering, Ceotechnical/Gecenvironmental)

REGISTRATION

Professional Engineer, State of Wisconsin, License No. 34108-006

ACADEMIC EXPERIENCE

Wisconsin Distinguished Professor, University of Wisconsin, Madison, Wisconsin, July 2007 topresent.

Chairman, Geological Engineering, University of Wisconsin, Madison, Wisconsin, July 2007 toJuly 2008, August 2009-present.

Director, Recycled Materials Resource Center, University of Wisconsin, Madison, Wisconsin,August 2007-present

Chairman, Dept. of Civil & Environmental Engineering, University of Washington, Seattle,Washington, July 1, 2008 to July 31, 2009

A.H. Fuller Chair in Civil and Environmental Engineering, University of Washington, Seattle,Washington, July 1, 2008 to July 31, 2009.

Associate Chairman for Environmental Science and Engineering, Dept. of Civil & EnvironmentalEngineering, University of Wisconsin, Madison, Wisconsin, July 2004 to June2007.

Professor, University of Wisconsin, Madison, Wisconsin, February 2000 to June 2007.

Associate Professor, University of Wisconsin, Madison, Wisconsin, May 1995 to January 200(1

Assistant Professor, University of Wisconsin, Madison, Wisconsin, January 1990 to May 1995.

Craig FL Benson, PhD, FE

HONORS AND AWARDS

ResearchDiplomate, Ceotechnical Engineering. Academy of Ceo-Professionals, 2009Academy of Distinguished Alumni, University of Texas at Austin, 2009Croes Medal, American Society of Civil Engineers, 2008Alfred P. Noble Prize, American Society of Civil Engineers, 2008lJOG Excellent Paper Award, Intl. Assoc. Computer Methods & Advances in Ceomechanics, 2008Second Paper Award, Global Waste Management Symposium, 2008Third Paper Award, Global Waste Management Symposium, 2008Kellet Mid-Career Research Award, University of Wisconsin, 2005Walter L. Huber Civil Engineering Research Award, ASCE, 2000Croes Medal, American Society of Civil Engineers, 1998Casagrande Award, American Society of Civil Engineers, 1995Middlebrooks Award, American Society of Civil Engineers, 1995Collingwood Prize, American Society of Civil Engineers, 1994Distinguished Young Faculty Award, US. Department of Energy, 1991Presidential Young Investigator, National Science Foundation, 1991

TeachingPolygon Outstanding Instructor Award, College of Engr., Univ. of Wisconsin, 1991, 93, 97Outstanding Professor Award, ASCE Wisconsin Student Chapter, 1992Top 100 Educators Award, Wisconsin Students Association, Univ. of Wisconsin, 1991

AcademicsJohn A. Focht Endowed Presidential Scholarship in Civil Engr., Univ. of Texas at Austin, 1988Dawson Endowed Presidential Scholarship in Civil Engr., Univ. of Texas at Austin, 1986Engineering Foundation Fellowship, University of Texas at Austin, 1985John B. Carson Prize in Civil Engineering, Lehigh University, 1985Phi Beta Kappa, Cli Epsilon, and Tau Beta Pi

PUBLICATIONS

Refereed Journal Articles: Waste Containment Systems

Abichou, T., Powelson, D., Aitchison, E., Benson, C., and Albright, W. (2005), Water Balances inVegetated Lysimeters at a Georgia Landfill, Soil and Crop Society of Florida Proc, 64,1-8.

Abichou, T., Benson, C., and Edil, T. (2004), Network Model for Hydraulic Conductivity of SandBentonite Mixtures, Canadian Geotech. J, 41(4), 698-712.

Abichou, T., Benson, C., and Edil, T. (2002), Micro-Structure and Hydraulic Conductivity ofSimulated Sand-Bentonite Mixtures, Clays and Clay Minerals, 50(5), 537-545.

Abichou, T., Benson, C., and Edil, T. (2002), Foundry Green Sands as Hydraulic Barriers: FieldStudy, j. Geotech. and Geoenvironmental Eng., 128(3), 206-215.

2

Craig H. Benson, PhD, PE

Abichou, T., Benson, C., and Edil, T. (2000), Foundry Green Sands as Hydraulic Barriers:Laboratory Study, ,t. Geotech. and Geoenvironmental Eng., 126(12), 1174-1183.

Abu-Hassanein, Z, and Benson, C., and Blotz, L. (1996), Electrical Resistivity of CompactedClays,]. Geoteclz. Ens., 122(5), 397-407.

Abu-Hassanein, Z and Benson, C., Wang, X., and Blotz, L. (1995), Determining Bentonite Contentin Soil-Bentonite Mixtures Using Electrical Conductivity, Geotech. Testing ]., 19(1), 51-57.

Albrecht, B. and Benson, C. (2002), Predicting Airflow Rates in the Coarse Layer of Passive DryBarriers,]. Geotech. and Geoenviron;nental Eng., 128(4), 338-346. i

Albrecht, B. and Benson, C. (2001), Effect of Desiccation on Compacted Natural Days,]. Geotech.and GeoenvironmentalEng., 127(1), 67-76.

Albright, W., Benson, C., Gee, C., Abichou, T., Tyler, S., Rock, 5. (2006), Field Performance ofThree Compacted Clay Landfill Covers, Vadose Zone J., 5(6), 1157-1171.

Albright, W., Benson, C., Gee, C., Abichou, T., Tyler, S., Rock, S. (2006), Field Performance of ACompacted Clay Landfill Final Cover at A Humid Site, I. Ceotech. and Geoenvironnzental Eng.,132(11), 1393-1403.

Albright, W., Benson, C., Gee, G., Roesler, A., Abichou, T., Apiwantragoon, P., Lyles, B., andRock, 5. (2004), Field Water Balance of Landfill Final Covers. ]. Environmental Qualiti, 33(6),2317-2332.

Akpinar, M. and Benson, C. (2005), Effect of Temperature on Shear Strength of TwoGeomembrane-Geotextile Interfaces, Geotextiles and Geomembranes, 23, 443453.

Benson, C. and Meer, 5. (2009), Relative Abundance of Monovalent and Diva]ent Cations and theImpact of Desiccation on Geosynthetic Day Liners,]. Geotech. and Geoenvironmental Eng., 135(3),349-358. M

Benson, C., Thorstad, P., Jo, H., and Rock, S. (2007), Hydraulic Performance of Geosynthetic ClayLiners in a Landfill Final Cover, j. Geotech. and Geoenvironmental Eng., 133(7), 814-827.

Benson, C., Barlaz, M., Lane, D., and Rawe, J. (2007), Practice Review of FiveBioreactor[Recirculation Landfills, Waste Management, 27(1), 13-29.

Benson, C., Sawangsuriva, A., Trzebiatowski, B., and Aibright, W. (2007), Post-ConstructionChanges in the Hydraulic Properties of Water Balance Cover Soils, ]. Geotech. andGeoenvironinental Eng., 133(4), 349-359.

Benson, C., Abichou, T., and Jo, H. (2004), Forensic Analysis of Excessive Leakage from LagoonsLined with a Composite GCL, Geosynthetics International, 110), 242-252. ‘

Benson, C. (2001), Waste Containment: Strategies and Performance, Australian Geo;nechanics,36(4), 1-25.

3


Benson, C., Abichou, T., Albright, W., Gee, C., and Roesler, A. (2001), Field Evaluation ofAlternative Earthen Final Covers, International J. Phytoremediation, 3(1), 1-21.

Benson, C, Daniel, D., and Boutwell, C. (1999), Field Performance of Compacted Cay Liners, J.Geotech. and Geoenvironinental Eng., 125(5), 390-403. t

Benson, C., Gunter, J., Boutwell, C., Trautwein, S., and Berzanskis, P. (1997), Comparison of FourMethods to Assess Hydraulic Conductivity,]. Geotech. and Geoenvironrnental Eng., 123(10), 929-937. 1

Benson, C., Olson, M., and Bergstrom, W. (1996), Temperatures of an Insulated Landfill Liner,].Transportation Research Board, 1534, 24-31.

Benson, C. and Trast, J. (1995), Hydraulic Conductivity of Thirteen Compacted Clays, Clays andClay Minerals, 43(6), 669-681.

Benson, C., Chamberlain, E., Erickson, A., and Wang, X. (1995), Assessing Frost Damage inCompacted Soil Liners, Geotech. Testing ]., 18(3), 324-333.

Benson, C., Abichou, T., Olson, M., and Bosscher, P. (1995), Winter Effects on the HydraulicConductivity of Compacted Cay,]. Geotech. Eng., 121(1), 69-79.

Benson, C., Zhai, H., and Wang, X. (1994), Estimating the Hydraulic Conductivity of CompactedClay Liners,]. Geotech. Eng., 120(2), 366-387.

Benson, C. and Daniel, D. (1994), Minimum Thickness of Compacted Soil Liners: I-StochasticModels,”]. Geotech. Eng., 120(1), 129-152.

Benson, C. and Daniel, D. (1994), Minimum Thickness of Compacted Soil Liners: 11-Analysis andCase Histories, J. Geotech. Eng., 1200), 153-172. I

Benson, C., Bosscher, P., Lane, D., and Pliska, R. (1994), Monitoring System for HydrologicEvaluation of Landfill Final Covers, Geotech. Testing]., 17(2), 138-149. 111

Benson, C., Thai, H. and Rashad, S. (1994), Statistical Sample Size for Construction of Soil Liners,

J. Geotech. Eng., 120(10), 1704-1724. i

Benson, C. (1993), Probability Distributions for Hydraulic Conductivity of Compacted Soil Liners,

]. Geotech. Eng., 119(3), 471 -486.

Benson, C. and Othman, M. (1993), Hydraulic Conductivity of Compacted Clay Frozen andThawed In Situ,]. Geotech. Eng., 119(2), 276-294.

Benson, C. and Daniel, D. (1990), Influence of Cods on the Hydraulic Conductivity of CompactedClay, J. Geoteclz. Eng., 116(8), 1231-1248.

4


Blotz, L, Benson, C., and Boutwell, C. (1998), Estimating Optimum Water Content and MaximumDry Unit Weight for Compacted Clays, J. Geotech. and Geoenvironnzental Eng., 124(9), 907-912.

Bohnhoff, G, Ogorzalek, A., Benson, C., Shackelford, C., and Apiwantragoon, R (2009),Comparison of Field Data and Water-Balance Predictions for a Monolithic Cover in a SemiArid Climate, J. Geotech. and Geoenvironmenta( Eng., 135(3), 333-338. t

Carpenter, A., Gardner, K., Fopiano, 5., Benson, C., and Edil, T. (2007), Life Cycle Based RiskAssessment of Recycled Materials in Roadway Construction, Waste Mgnt., 27, 1438-1464.

Daniel, D. and Benson, C. (1990), Water Content-Density Criteria for Compacted Soil Liners, I.Geotech. Eng., 116(12), 1811-1830. t!

Foose, C., Benson, C., and Edil, T. (2002), Comparison of Solute Transport in Three CompositeLandfill Liners, J. Geotech. and Ceoenvironinen nil Eng., 128(5), 391-403.

Foose, C., Benson, C-, and Edil, T. (2001), Predicting Leakage Through Composite Landfill Liners,

J. Geotech. and Geoenviron. Eng., 127(6), 510-320.

Foose, C., Benson, C-, and Edil, T. (2001), Analytical Equations for Predicting Concentration andMass Flux from Composite Landfill Liners, Geosi1nthetics International, 8(6), 551-375.

Gulec, S., Benson. C., and Edil, T. (2005), Effect of Acidic Mine Drainage (AMD) on theMechanical and Hydraulic Properties of Three Ceosynthetics, j. Geotech. and GeoenvironnrentalEng.. 131(8), 937-950.

Gulec, S., Edil, T., and Benson, C. (2004), Effect of Acidic Mine Drainage (AMD) on the PolymerProperties of an HDPE Geomembrane, Geosynthetics international, 11(2), 60-72.

Jacobson, K., Lee, S., McKenzie, D., Benson, C., and Pedersen, 5. (2008), Transport of thePathogenic Prion Protein Through Landfill Materials, Environmental Science & Technology, 43(6),2022-2028. t

Jo, H., Benson, C., and Edil, T. (2006), Rate-Limited Cation Exchange in Thin Bentonitic BarrierLayers, Canadian Geotech. J., 43, 370-391.

Jo, H., Benson, C., Lee, 5., Shackelford, C., and Edil, T. (2005), Long-Term Hydraulic Conductivityof a Non-Prehydrated Geosynthetic Clay Liner Permeated with Inorganic Salt Solutions, j.Geotech. and Geoenvironmental Eng., 131(4), 405-417. .

Jo, H., Benson, C., and EdiI, T. (2004), Hydraulic Conductivity and Cation Exchange in NonPrehydrated and Prehydrated Bentonite Permeated with Weak Inorganic Salt Solutions, Claysand Clay Minerals, 52(6), 661-679.

Jo, H., Katsumi, T., Benson, C., and Edil, T. (2001), Hydraulic Conductivity and Swelling of NonPrehydrated Gas Permeated with Single Species Salt Solutions, j. of Geotech. andGeoenvironmental Eng., 127(7), 557-567.

5

Craig H. Benson, PhD. FE

Katsumi, T., Benson, C., Foose, C., and Kamon, M. (2001), Performance-Based Design of LandfillLiners, Engineering Ceologij, 60, 139-148. ‘

Katsurni, T., Benson, C., Foose, C., and Kamon, M. (1999), Evaluation of the Performance ofLandfill Liners, J. Japan Society of Waste Management, 100), 75-85.

Khire, M., Benson, C., and Bosscher, P. (2000), Capillary Barriers: Design Variables and WaterBalance, J. Geotech. and Ceoenvironmentul Lag., 126(8), 695-708. 1

Khire, M., Benson, C., and Bosscher, P. (1999), Field Data from a Capillary Barrier in Semi-Aridand Model Predictions with UNSAT-H, J. Geotech. and Geoenvironnzental Eng., 125(6), 518-528.

Khire, M., Benson, C., and Bosscher, P. (1997), Water Balance of Two Earthen Landfill Caps in aSemi-Arid Climate, J. Land Contamination and Reclamation, 5(3), 195-202.

Khire, M., Benson, C., and Bosscher, P. (1997), Water Balance Modeling of Earthen LandfillCovers, J. Geotech. and Geoenvzronmental Eng., 123(8), 744-754.

Kim, H. and Benson, C. (2004), Contributions of Advective and Diffusive Oxygen TransportThrough Multilayer Composite Caps Over Mine Waste,]. Contaminant Hydrology, 71(1-4), 13-218.

Kolstad, D., Benson, C., and Edil, T. (2004), Hydraulic Conductivity and Swell ofNonprehydrated GCLs Permeated with Multi-species Inorganic Solutions, I. Geotech. andGeoenvironmental Eng., 13002), 1236-1249.

Kolstad, D., Benson, C., Edil, T., and Jo, H. (2004), Hydraulic Conductivity of a DensePrehydrated CCL Permeated with Aggressive Inorganic Solutions, Geosynthetics International,11(3), 233-240.

Kraus, J., Benson, C., Erickson, A., and Chamberlain, E. (1997), Freeze-Thaw and HydraulicConductivity of Bentonitic Barriers, J. Geotech. and Geoenvironmental Eng., 123(3) 229-238.

Kraus, J., Benson, C., Maitby, V., and Wang. X. (1997), Field and Laboratory HydraulicConductivity of Compacted Papermill Sludges, J. Geotech. and Geoenviron,nental Eng., 123(7),654-662.

Lee, J., Shackelford, C., Benson, C., Jo, H., and Edil, T. (2005), Correlating Index Properties aridHydraulic Conductivity of Geosynthetic Clay Liners, J. Geeteclz. and Geoenvironmental Eng.,131(11), 1319-1329.

Lin, L. and Benson, C. (2000), Effect of Wet-Dry Cycling on Swelling and Hydraulic Conductivityof Ceosynthetic Clay Liners,]. Geotech. and Ceoenviron,nen (a! Eng., 1260), 40-49.

Ma, X., Benson, C., D. McKenzie, J. Aiken, and J. Pedersen (2007), Adsorption of Pathogenic PrionProtein to Quartz Sand, Environmental Science and Technology, 41(7), 2324-2330. tfl

6

Craig I-I. Benson, PhD. PE

Meer, S. and Benson, C. (2007), Hydraulic Conductivity of Geosynthetic Clay Uners Exhumed

from Landfill Final Covers,]. Geotech. and Geoenz’ironrnental Eng., 133(5), 550-563.

Meerdink, J., Benson, C., and Khire, M. (1995), Unsaturated Hydraulic Conductivity of Two

Compacted Barrier Soils, J. Geotech. Eng., 122(7), 565-576.

Ogorzalek, A., Bohnhoff, C., Shackelford, C., Benson, C., and Apiwantragoon, P. (2007),Comparison of Field Data and Water-Balance Predictions for a Capillary Barrier Cover. J.Geotech. and Geoenvironmental Eng., 134(4), 470-486.

Othman, M. and Benson, C. (1994), Effect of Freeze-Thaw on the Hydraulic Conductivity and

Morphology of Compacted Clay, Canadian Geotech. ]., 30(2), 236-246.

Othman, M. and Benson, C. (1993), Effect of Freeze-Thaw on the Hydraulic Conductivity of ThreeCompacted Clays from Wisconsin, J. Transportation Research Board, 1369, 118-125. t!

Palmer, B., Edil, T. and C. H. Benson (2000), Liners for Waste Containment Constructed with

Class F and C Fly Ashes, J. Hazardous Materials, 18( 2-3), 133-161.

Shackelford, C., Benson, C., Katsumi, T., and Edil, T. (2000), Evaluating the HydraulicConductivity of GCLs Permeated with Non-Standard Liquids, J. Geotextiles and Geotnenibranes,18(2-3), 133-161.

Smesrud, J., Benson, C., Albright, W., Richards, J., Wright, S., Israel, T., and Goodrich, K. (2009),Using Pilot Test Data to Refine an Alternative Cover Design in Northern California,International J. Phijtoremediation, 3(1), in press.

Tinjum, J., Benson, C., and Blotz, L. (1997), Soil-Water Characteristic Curves for CompactedClays, I- Geotech. and Geoenvironnzenta! Eng., 123(11), 1060-1070.

Trast, J. and Benson, C. (1995), Estimating Field Hydraulic Conductivity of Compacted Clay, I.Geotech. Eng., 121 (10), 736-740.

Wang, X. and Benson, C. (1999), Hydraulic Conductivity Testing of Geosynthetic Clay LinersUsing the Constant Volume Method, Geotechnical Testing J., 22(4), 277-283.

Wang, X. and Benson, C. (1995), Infiltration and Field-Saturated Hydraulic Conductivity ofCompacted Clay, J. Geotech. Eng., 121(10), 713-722. t!

Thai, H. and Benson, C. (2006), The Log-Normal Distribution for Hydraulic Conductivity ofCompacted Clays: Two or Three Parameters?, Geotechnical and Geological Engineering, 24(5),1149-1162.

Refereed Journal Articles: Sustainable Construction

Benson, C. and Othman, M. (1993), Hydraulic and Mechanical Characteristics of CompactedMunicipal Solid Waste Compost, Waste Management and Research, 11(1), 127-142.

/

Craig H. Benson, PhD. PE

Benson, C and Khire, M (1994), Reinforcing Sand with Strips of Reclaimed High DensityPolyethylene, J. Geotech. Eng., 120(5), 838-855.

Bin-Shafique, S., Benson, C., Edil, T., and Hwang, K. (2006), Leachate Concentrations from WaterLeach and Column Leach Tests on Fly-Ash Stabilized Soi], Environmental Engineering Science,23(1),51-65.

Bin-Shafique, S., Edil, T., and Benson, C (2004), Incorporating a Fly Ash Stabilized Layer intoPavement Design — Case Study, Geotechnical Engineering, 157(4), 239-249. t

Dingrando, J., Edil, T., and Benson, C. (2004), Beneficial Reuse of Foundry Sands in ControlledLow Strength Material, j. ASTM International, 1(6), 1-12. ti

Edil, T., Acosta, H., and Benson, C. (2006), Stabilizing Soft Fine-Grained Soils with Fly Ash, J.Materials in Civil Engineering, 18(2), 283-294.

Edil, T., Benson, C., Bin-Shafique, M., Tanyu, B., Kim, W., and Senol, A. (2002), Field Evaluationof Construction Alternatives for Roadway Over Soft Subgrade, ,l. Transportation Research Board,1786, 36-48. ti

Foose, G., Benson, C., and Bosscher, P. (1996), Sand Reinforced with Shredded Waste Tires, I.Geotech. Eng., 122(9), 760-767. ti

Goodhue, M.. Edil, T., and Benson, C. (2001), Interaction of Foundry Sands with Geosynthetics, J.Geotech. and Geoenvironmental Eng., 127(4), 353-362. ti

Kleven, J., Edil, T., and Benson, C. (2000), Evaluation of Excess Foundry System Sands for Use asSubbase Material, J. Transportation Research Board, 1714,40-48. ti

Lee, T. and Benson, C. (2006), Leaching Behavior of Green Sands from Gray-Iron Foundries Usedfor Reactive Barrier Applications, Environmental Engineering Science, 23(1), 153-167.

Li, L., Benson, C, Edil, T., and Halipoglu, B. (2007), Groundwater Impacts from Coal Ash inHighways, Waste and Resource Management, 159(4), 151 -1 62.

Li, L, Benson, C., Edil, T., and Hatipoglu, B. (2008), Sustainable Construction Case History: FlyAsh Stabilization of Recycled Asphalt Pavement Material, Geotechnical and GeologicalEngineering, 26, 177-187. ti

Senol, A., Edil, T., Bin-Shafique, S., Acosta, H., and Benson, C. (2006), Soft Subgrade StabilizationUsing Fly Ashes, Resources, conseroation and Recycling, 46(4), 365-376. ti

Senol, A., Bin-Shafique, S., Edil, T., and Benson, C. (2003), Use of Class C Fly Ash for Stabilizationof Soft Subgrade, ARI, Bulletin Istanbul Technical University, 53(1), 98-104.

8

Craig F]. Benson. PhD. PE

Tanyu, B., Kim, W., Edil, T., and Benson, C., (2006), Development of Methodology to includeStructural Contribution of Alternative Working Platforms in Pavement Structure, J.Transportation Research Board, 1936, 70-77.

Tanyu, B., Benson, C., Edil, T., and Kim, W. (2005), Equivalency of Crushed Rock and ThreeIndustrial By-Products Used For Working Platforms During Pavement Construction, J.Transportation Research Board, 1874, 59-69. ttl

Tatlisoz, N., Edil, T., and Benson, C. (1998), Interaction between Reinforcing Geosynthetics andSoil-Tire Chip Mixtures, J. Geotech. and Geoenvironmental Eng., 124(11), 1109-1119.

Trzebiatowski, B. and Benson, C. (2005), Saturated Hydraulic Conductivity of CompactedRecycled Asphalt Pavement, Geotech. Testing J., 28(5), 514-519.

Refereed Journal Articles: Remediation and Groundwater Monitoring

Alumbaugh, D., Simon, D. and Benson, C. (2005), Comparison of Three Geophysical Methods forCharacterizing Air Flow from an Air Sparging Well, Near Surface Geophysics, Part 11: Applicationsand Case Histories, Society of Exploration Geophysicists, 20, 1-12.

Baker, D. and Benson, C. (2007), Effect of System Variables and Particle Size on PhysicalCharacteristics of Air Sparging Plumes, Geotechnical and Geological Engineering, 25(5), 543-558.

Christman, M., Benson, C., and Edil, T. (2002), Geophysical Evaluation of Annular Well Seals,Ground Water Monitoring and Reinediation, 22(3), 104-112.

Cope, D. and Benson, C. (2009), Grey-Iron Foundry Slags As Reactive Media for RemovingTrichloroethylene from Groundwater, Environ. Science & Technology, 43(1), 169-175. tt

Elder, C., Benson, C., and Eykholt, G. (2002), Effects of Heterogeneity on Influent and EffluentConcentrations from Horizontal Permeable Reactive Barriers, Water Resources Research, 38(8),27-1 to 27-2.

Elder, C. and Benson, C., and Eykholt, G. (1999), Modeling Mass Removal During in Situ AirSparging, j. Geotech. and Geoenviron. Eng., 125(11), 947-958.

Elder, C. and Benson, C. (1999), Air Channel Formation, Size, Spacing, and Tortuosity During AirSparging, Ground Water Monitoring and Reinedintion, 19(3), 171-181.

Eykholt, C., Elder, C., and Benson, C. (1999), Effects of Aquifer Heterogeneity and ReactionMechanisms Uncertainty on a Reactive Barrier, J. Hazardous Materials, 68, 73-96. !!

Foose, C., Tachavises, C., Benson, C., and Edil, T. (1998), Analyzing GeoenvironmentalEngineering Problems Using MODFLOW, Naresuan University J., Thailand, 6(2), 38-44.

9

Craig H. Benson, PhD, FE

I.ee, T. and Benson, C. (2004), Using Waste Green Sands for Treating Alachior and Metolachlor inGroundwater, J. Environmental Quality, 33(5), 1682-1693.

Lee, T., Benson, C, and Eykholt, G. (2004), Waste Green Sands as Reactive Media forGroundwater Contaminated with Trichloroethylene, J. Hazardous Materials, 109 (1-3), 25-3&

Lee, T. and Benson, C. (2000), Flow Paste Bench-Scale Vertical Groundwater Cut-Off Walls, 5.Geotech. and Groenvironmenial Eng., 126(6) 511-520.

Li, L., Benson, C., and Lawson, E. (2006), Modeling Porosity Reductions Caused by MineralFouling in Continuous-Wall Permeable Reactive Barriers,). Contaminant Hydrology, 83 (1-2), 89-121. t!

Li, L., Benson, C., and Lawson, E. (2005), Impact of Mineral Fouling on Hydraulic Behavior ofPermeable Reactive Barriers, Ground Water, 43(4), 582-596.

Pekarun, 0., Benson, C., and Edil, T. (1997), Significance of Defects in Annular Well Seals, PracticePeriodical Hazardous, Toxic, and Radioactive Waste, 2(2)1-7.

Tinjum, J., Benson, C., and Edil, T. (2008), Mobilization of Cr(Vl) from Chromite Ore ProcessingResidue through Add Treatment, Science of the Total Environment, 391,13-25. tfl

Tinjum, j., Benson, C., and Edil, T. (2008), Treatment of Cr(Vl) in Chromium Ore ProcessingResidue Using Ferrous Sulfate-Sulfuric Add or Cationic Polysulfides, 5. Geotech. andGeoenviron. Eng., 134(12), 1791-1803.

Vesiller, N., Benson, C., and Edil, T. (1997), Field Evaluation of an Ultrasonic Method forAssessing Well Seals, Ground Water Monitoring and Reinediation, 17(3), 169-177.

Yesiller, N., Edil, T., and Benson, C. (1997), Ultrasonic Method for Evaluation of Annular Seals forWells and Instrument Holes, Geotech. Testing 5., 20(1), 17-28.

Refereed Journal Articles: Other Topics

Albrecht, B., Benson, C., and Beuermann, 5. (2003), Polymer Capacitance Sensors for MeasuringSoil Gas Humidity in Drier Soils, Geotech. Testing I., 26(1)3-12. ‘r

Bareither, C., Benson, C., and Edil, T. (2008), Reproducibility of Direct Shear Tests Conducted onGranular Backfill Materials, Geotechnical Testing 5., 31(1)1-11.

Bareither, C., Benson, C., and Edil, T. (2008), Comparison of shear strength of sand backfillsmeasured in small-scale and large-scale direct shear tests, Canadian Geotechnical 5., 45, 1242-1236.

10

Craig H. Benson. PhD, PE

Bareither, C., Edil, T., Benson, C., and Mickelson, D. (2008), Geological and Physical FactorsAffecting the Friction Angle of Compacted Sands, J Geotecli. and Geoenvironmental Eng., 134(10),1476-1489.

Chalermyanont, T. and Benson, C. (2005), Reliability Based Design for External Stability ofMechanically Stabilized Earth (MSE) Walls, International J. Geo;nechanics, 5(3), 196-201

Chalermyanont, T. and Benson, C. (2004), Reliability-Based Design for Internal Stability ofMechanically Stabilized Earth (MSE) Walls, f Geotech. and Geoenvironmental Eng., 130(2),163-173.

Fall, NI., Sawangsuriya, A., Benson, C., Edil, T., and Bosscher, R (2008), Resilient Modulus ofResidual Tropical Gravel Lateritic Soils from Senegal (West Africa), Geotechnical and GeologicalEngineering, 26, 13-35.

Jong, D., Bosscher, P., and Benson, C. (1998), Field Assessment of Changes in Pavement ModuliCaused by Freezing and Thawing, J. Transport at ion Research Board, 1615,41-5th

Kanitpong, K., Benson, C., and Bahia, H. (2001), Hydraulic Conductivity (Permeability) ofLaboratory-Compacted Asphalt Mixtures, J. Transportal ion Research Board, 1767, 25-33.

Kim, W., Edil, T., Benson, C., and Tanyu, B., (2006), Deflection of Prototype GeosyntheticReinforced Working Platforms Over Soft Subgrade, J. Transportation Research Board, 1975, 137-145.

Kim, W., Edii, T., Benson, C., and Tanyu, B., (2006), Structural Contribution GeosyntheticReinforced Working Platforms in Flexible Pavement, I. Transportation Research Board, 1936, 43-

Mengelt, M., Edil, T., and Benson, C. (2006), Resilient Modulus and Plastic Deformation of SoilConfined in a Geocell, Geosynthetics International, 13(5), 1-11. 7.

Russell, J, Benson C., and Fox, P. (1990), A Stochastic Decision Model for ContractorPrequalification, Microcomputers in Civil Engineering, 5(4), 285-297.

Sawangsuriya, A., Edil, T., and Benson, C. (2008), Effect of Suction on the Resilient Modulus ofCompacted Fine-Crained Subgrade Soils, j. Transportation Research Board, in press.

Suwansawat, S. and Benson, C. (1998), Cell Size for Water Content-Dielectric ConstantCalibrations for Time Domain Reflectometry, Geotechnical Testing J., 22(1), 3-12.

Yesiller, N., Benson, C., and Bosscher, P. (1996), Comparison of Load Restriction TimingsDetermined Using FHWA Guidelines and Frost Tubes,] Cold Regions Eng., 10(1), 6-24.

Wang, X. and Benson, C. (2004), Leak-Free Pressure Plate Extractor for Measuring the Soil WaterCharacteristic Curve, Geotech. Testing J., 27(2), 1-10.

11

Craig H. Benson, PhD. PC

Refereed Conference Papers

Ahichou, T., Edil, T., Benson, C., and Tawfiq, K. (2004), Hydraulic Conductivity of FoundrySands and Their Use as Hydraulic Barriers, Beneficial Reuse of Waste Materials in Ceo!echnical andTransportation Applications, GSP No. 127, A. Aydilek and J. Wartman, eds., ASCE, Reston, VA,186-200.

Abichou, T., Tawfiq, K., Edil, T., and Benson, C., (2004), Behavior of a Soil-Tire Shreds Backfill forModular Block Wall, Beneficial Reuse of Waste Materials in Geotechnical and TransportationApplications, GSP No. 127, A. Aydilek and J. Wartman, eds., ASCE, Reston, VA, 162-172.

Abichou, T., Benson, C., Friend, M., and Wang, X. (2002), Hydraulic Conductivity of a FracturedAquitard, Evaluation and Reniediation of Law Penneahility and Dual Porosity Environments, STP1415, M. Sara and L. Everett, Eds., ASTM International, West Conshohocken, PA, 25-39.

Abichou, T., Benson, C., and Edil, T. (1998), Database on Beneficial Reuse of Foundry ByProducts, Recycled Materials in Geotechnical Applications, GSP No. 79, ASCE, C. Vipulanandanand I). Elton, eds., 210-224.

Abichou, T., Benson, C., Edil, T., and Freber, B. (1998), Using Waste Foundry Sand for HydraulicBarriers, Recycled Materials in Geotechnical Applications, GSP Na 79, ASCE, C. Vipulanandan andD. Elton, eds., 86-99. i

Apiwantragoon, P., Benson, C., and Aibright, W. (2003), Comparison of Water BalancePredictions Made with HYDRUS-2D and Field Data from the Alternative Cover AssessmentProgram (ACAP), Proc. MODFLOW and More 2003: Understanding through Modeling,International Groundwater Modeling Center, Golden, CO. 751-755.

Baker, D. and Benson, C. (19%), Factors Affecting In Situ Air Sparging, Non-Aqueous Phase Liquidsin Subsurface Reinediation, ASCE, L. Reddi, ed., 292-3l0.

Bareither, C., Breitmeyer, R., Erses, A., Benson, C., Edil, T., and Barlaz, M. (2008), RelativeContributions of Moisture and Biological Activity on Compression of Municipal Solid Waste thBioreactor Landfills, Proceedings. Global Waste Management Syinposiuni 2008, Fenton Media,Orlando, 1-9.

Benson, C., Wang, X., Cassner, F., and Foo, D. (2008), Hydraulic Conductivity of TwoGeosvnthetic Clay Liners Permeated with an Aluminum Residue Leachate, GeoAmericas 2008,International Geosynthetics Society.

Benson, C. (2007), Modeling Unsaturated Flow and Atmospheric Interactions, Theoretical andNumerical Unsaturated Soil Mechanics, T. Schanz, Ed., Springer, Berlin, l87-202

Benson, C. and Wang, X. (2006), Temperature-Compensating Calibration Procedure for WaterContent Reflectometers, Proceedings TDR 2006: 3rd international Symposium and Workshop onTime Domain Reflectoinetnj for innovative Soils Applications, Purdue University, West Lafayette,IN, USA, 50-1 - 5-16.

12


Benson, C., Bolmhoff, C., Ogorzalek, A., Shackelford, C., Apiwantragoon, P., and Albright, W.(2005), Field Data and Model Predictions for an Alternative Cover, Waste Containment andReinediation, GSP No.142, A. Alshawabkeh et al., eds., ASCE, Reston, VA, 1-12.

Benson, C., Tipton, R., Kumthekar, U, and Chiou, J. (2003), Web-Based Remote MonitoringSystem for Long-Term Stewardship of a Low-Level Radioactive Waste Disposal Facility, Proc.Ninth International Conference on Radioactive Waste Management and Environmental Remediatiun,ASME, S16, 1-6.

Benson, C. and Chen, C. (2003), Selecting the Thickness of Monolithic Earthen Covers for WasteContainment, Soil and Rock America 2003, Verlag Cluck auf GMBH, Essen, Germany, 1397-1404.

Benson, C. (2002), Contaimnent Systems: Lessons Learned from North American Failures,Environmental Geotechnics (4tJs ICEG), Swets and Zeitlinger, Lisse, 1095-1112. t!]

Benson, C., Albright, W., Roesler, A., and Abichou, T. (2002), Evaluation of Final CoverPerformance: Field Data from the Alternative Cover Assessment Program (ACAP), Proc. WasteManagement ‘02, Tucson, AZ.

Benson, C. (2001), Waste Containment: Strategies & Performance, Proc. Geoenvironniental 2001,Australia-New Zealand Geomechanics Society, D. Smith, S. Fytus, & M. AlIman, eds., 23-52. ti

Benson, C. and Boutwell, G. (2000), Compaction Conditions and Scale-Dependent HydraulicConductivity of Compacted Clay Liners, Constructing and Controlling Compaction qf Earth Fills,ASTM STP 1384, D. Shanklin, K. Rademacher, and ). Talbot, Eds., ASTM, 254-273. tfl

Benson, C. and Wang, X. (2000), Hydraulic Conductivity Assessment of Hydraulic BarriersConstructed with Paper Sludge, Ceotechnics ofHigh Water Content Materials, SW 1374, ASTM, T.Edil and P. Fox, Eds., 91-107.

Benson, C- and Bosscher, P. (1999), Remote Field Methods to Measure Frost Depth, FieldInstrumentation for Soil and Rock, SW 1358, ASTM, C. Durham and W. Man, Eds., 267-284.

Benson, C. and Bosscher, P. (1999), Time-Domain Reflectometrv in Geotechnics: A Review,Nondestructive and Automated Testing for Soil and Rock Properties, STP 1350, ASTM, W. Marr andC. Fairhurst, Eds., 113-136. t!

Benson, C. and Gribb, M. (1997), Measuring Unsaturated Hydraulic Conductivity in theLaboratory and Field, Unsaturated Soil Engineering Practice, GSP No. 68, ASCE, S. Houston andD. Fredlund, eds., 113-168.

Benson, C. mid Khire, M. (1995), Earthen Covers for Semi-Arid and Arid Climates, LandfillClosures, ASCE, GSP No.53,). Dunn and U. Singh, eds., 201-21 7.

Benson, C, Tinjurn, J., and Hussin, C. (1995), Leakage Rates Through Ceomembranes ContainingHoles, Geosynthetics 95, Industrial Fabrics Assoc. Intl., St. Paul 745-758. 1

13


Benson, C., Hardianto, F., and Motan, Ii (1994), Representative Specimen Size for HydraulicConductivity of Compacted Soil Liners, Hydraulic Conductivity and Waste Containment Transportin Soils, STP 1142, ASTM, S. Trautwein and Ii Daniel, eds., 3-29.

Benson, C. and Khire, M. (1993), Soil Reinforcement with Strips of Reclaimed HDPE, Geosynthetics93, Industrial Fabrics Assoc. Intl., St. Paul, 935-948. 1

Benson, C. and Charbeneau, K. (1991), Reliability Analysis for Time of Travel in Compacted SoilLiners, Geotecl;nical Congress 1991, ASCE, GSP No. 27, 456-467.

Bergstrom, W., Creamer, P., Petrusha, H., and Benson, C. (1994), Field Performance of a DoubleLiner Test Pad, Geoenvironment 2000, CSP No.46, ASCE, 608-623.

Bosscher, P., Jong, D., and Benson, C. (1998), Software to Establish Seasonal Load Limits forFlexible Pavements, Cold Regions Impact on Civil Works, D. Newcomb, ed., ASCE, 731-747.

Breitmeyer, K., Bareither, C., Benson, C., Edil, T., and Barlaz, M. (2008), Field-Scale LysimeterExperiment to Study Hydrologic and Mechanical Properties of Municipal Solid Waste,Proceedings, Global Waste Management Symposium 2008, Penton Media, Orlando, 1-11.

Chalermyanont, T. and Benson, C. (2005), Method to Estimate the System Probability of Failure ofMechanically Stabilized Earth Walls, Slopes and Retaining Structures Under Seismic and StaticConditions, GSP No. 140, M. Gabr et al., eds., ASCE, Reston, VA, 1-15.

Chamberlain, E., Erickson, A. and Benson, C. (1994), Effecls of Frost Action on Compacted ClayBarriers, Geoenvironment 2000, ASCE, GSP No.46, 702-717.

Dingrando, J., Edit, T., and Benson, C. (2004), Beneficial Reuse of Foundry Sands in ControlledLow Strength Material, Innovations in Controlled Low-Strength Material (Plowable Fill), STP 1459, J.Hitch, A. Howard, and W. Bass, eds., ASTM, West Conshohocken, PA.

Edil, T. and Benson, C. (1998), Ceotechnics of Industrial Byproducts, Recycled Materials inGeotechnical Applications, GSP No. 79, ASCE, C. Vipulanandan and D. Elton, eds., 1-18.

Elder, C., Benson, C., and Eykholt, C. (1997), A Model for Predicting Mass Removal During AirSparging, In Situ Remediation of the Geoenvironrnent, GSP No. 71, j. Evans, ed., ASCE, Reston,VA, 83-97.

Foose, C., Benson, C., and Edil, T. (1999), Equivalency of Composite Ceosynthetic Clay Liners asa Barrier to Volatile Organic Compounds, Geosynthetics 99, International Fabrics AssociationInternational, St. Paul, MN, 321-334.

Foose, C., Benson, C., and Edil, T. (1996), Evaluating the Effectiveness of Landfill Liners, Proc. 2ndInternational Conference on Environmental Geotechnics, Osaka, Japan, 217-221.

Khire, M., Benson, C., and Bosscher, P. (1997), Water Balance of Two Earthen Landfill Caps in aSemi-Arid Climate, Intl. Containment Tech., 252-261.

14


Khire, M., Meerdink, J., Benson, C., and Bosscber, P. (1995), Unsaturated Hydraulic Conductivityand Water Balance Predictions for Earthen Landfill Final Covers, Soil Suction Applications inGeotechnical Engineering Practice, ASCE, GSP No. 48, W. Wray and S. Houston, eds., 38-57.

Koragappa, N., Wall, R., and Benson, C. (2008), Water Balance Cover — Case Study of a SouthernCalifornia Landfill, Proceedings, Global Waste Management Symposium 2008, Penton Media,Orlando, J-15.’2

Li, L and Benson, C. (2005), Impact of Fouling on the Long-Term Hydraulic Behavior ofPermeable Reactive Barriers, Permeable Reactive Barriers, Publication 298, International Assoc. ofHydrological Sciences, Oxfordshire, UK, C. Boshoff and B. Bone, eds., 23-32.

Li, L., Benson, C., Edil, T., and Hatipoglu, B. (2006), WiscLEACH: A Model for Predicting GroundWater Impacts from Fly-Ash Stabilized Layers in Roadways, Geotechnical Engineering in theInformation Technology Age, D. DeGroot, J. DeJong, J. Frost, and L. Baise, eds., ASCE.

Li, L., Mergener, E., and Benson, C. (2003), Reactive Transport Modeling of Mineral Fouling inPermeable Reactive Barriers, Proc. MODFLOW and More 2003: Understanding through Modeling,International Groundwater Modeling Center, Golden, CO, 300-304.

Malusis, M. and Benson, C. (2006), Lysimeters versus Water-Content Sensors for PerformanceMonitoring of Alternative Earthen Final Covers, Unsaturated Soils 2006, ASCE GeotechnicalSpecial Publication No. 147, 1, 741-752.

Manassero, M., Benson, C., and Bouazza, M. (2000), Solid Waste Containment Systems, Proc.GeoEng2000, Melbourne, Australia, Technomic Publishing Company, Lancaster, PA, USA, 520-642.

Ogorzalek, A., Shackelford, C., and Benson, C. (2005). Comparison of Model Predictions andField Data for an Alternative Cover in a Semiarid Climate, Symposium on Mines and theEnvironment, Canadian Institute of Mining, Metallurgy, and Petroleum, Montreal, Quebec, 666-680.

Othman, M., Benson, C., Chamberlain, E., and Zimmie, T. (1994), Laboratory Testing to EvaluateChanges in Hydraulic Conductivity Caused by Freeze-Thaw: State-of-the-Art, HydraulicConductivity and Waste Containment Transport in Soils, STP 1)42, ASTM, S. Trautwein and D.Daniel, eds., 227-254. t

Rauen, T. and Benson, C. (2008), Hydraulic Conductivity of a Geosynthetic Clay Liner Permeatedwith Leachate from a Landfill with Leachate Recirculation, GeoAmericas 2008, InternationalGeosynthetics Society.

Shackelford, C. and Benson, C. (2006), Selected Factors Affecting Water-Balance Predictions forAlternative Covers Using Unsaturated Flow Models, Geotechnical Engineering in the InformationTechnology Age, D. DeCroot, J. DeJong, j. Frost, and L. Baise, eds., ASCE. t

Sawangsuriya, A., Edil, T., Benson, C. and Wang, X., A Simple Setup for Inducing Manic Suction,Third Asian Conference on Unsaturated Soils, 2007, Nanjing, China.

15

Craig H. Benson, PhD, [‘F

Smesi-ud, J, Benson, C., Albright, W., Richards, J., Wright S., Israel, T., and Goodrich, K. (2008),Lessons Learned from an Alternative Cover Pilot Test in Northern California, Proceedings,Global Waste Management Symposium 2008, Fenton Media, Orlando, 1-20.

Tachavises, C. and Benson, C. (1997), Flow Rates Through Earthen, Ceomembrane, andComposite Cut-off Walls, Intl. Cbntainment Tech., 945-953.

Tachavises, C. and Benson, C. (1997), Hydraulic Importance of Defects in Vertical GroundwaterCutoff Walls, In Situ Remediation of the Geoenvironment, GSP No. 71, J. Evans, ed., ASCE, Reston,VA, 168-180.

Tanyu, B., Kim, W., Edil, T., and Benson, C. (2003), Comparison of Laboratory Resilient Moduluswith Back-Calculated Elastic Moduli from Large-Scale Model Experiments and FWD Tests onGranular Materials, Resilient Modulus Testing for Pavement Components, STP 1437, C. Durham, A.Man, and W. De Croft eds., ASTM, West Conshohocken, PA, 191-208.

Tallisoz, N., Benson, C., and Edil, T. (1997), Effect of Fines on the Mechanical Properties of Soil-Tire Chip Mixtures, Testing Soil Mixed with Waste or Recycled Materials, STP 1275, ASTM, M.Wasemiller and K. Hoddinott, eds., 93-108.

Trzebiatowski, B., Edil, T., and Benson, C. (2004), Case Study of Subgrade Stabilization Using FlyAsh: State Highway 32, Port Washington, Wisconsin, Beneficial Reuse of Waste Materials inGeotechnical and Transportation Applications, GSP No. 127, A. Aydilek and J. Wartman, eds.,ASCE, Reston, VA, 123-136.

Vasko, 5., Jo, H., Benson, C., Edil, T., and Katsumi, T. (2001), Hydraulic Conductivity of PartiallyPrehydrated Geosynthetic Clay Liners Permeated with Aqueous Calcium Chloride Solutions,Geosynthetics 2001, Industrial Fabrics Assoc. International, St. Paul, MN, 685-699.

Waugh, W., Benson, C., and Albright, W. (2008), Monitoring the Performance of an AlternativeLandfill Cover Using a Large Embedded Lysimeter, Proceedings, Global Waste ManagementSymposium 2008, Fenton Media, Orlando, 1-10.

Waugh, W., Benson, C., and Albright, W. (2009), Sustainable Covers for Uranium Mill Tailings,USA: Alternative Design, Performance, and Renovation, Proc. 121k International Conference onEnvironmental Remediation and Radioactive Waste Management, ICEM2009, ASME, 1145 October2009, Liverpool, UK.

Wright S., Arcement, B., and Benson, C. (2003), Comparison of Maximum Density ofCohesionless Soils Determined Using Vibratory and Impact Compaction Methods, Soil and RockAmerica 2003, Verlag Cluck auf CMBH, Essen, Germany, 1709-1716.

Discussions

Benson, C. and Edil, T. (2004) Comment on “A Polymer Membrane Containing FeD as aContaminant Barrier” by T. Shimitori et al., Environ. Science and Tech., 38(19), 5263.

16


Chapters in Books

Benson, C. (2005), Materials Stability and Applications, in Barrier Systems for EnvironmentalContaminant Containment and Treatment, C. Chen, H. Inyang, and L. Everett, eds., CRC Press,Boca Raton, FL, 143-208.

Doyle. M., Lee, S., Benson, C., and Pariza, M. (2009), Decontamination and Disposal ofContaminated Foods, Wiley Handbook of Science and Technology for Homeland Security, J. Voeller,ed., John Wiley and Sons, NY, 1-15.

Li, L. and Benson, C. (2005), Reactive Transport in the Saturated Zone: Case Histories forPermeable Reactive Barriers, Water Encyclopedia, Volume I — Ground Water, J. Lehr and JackKeeley, eds., John Wiley, 51 8-524.

Non-Refereed Conference Papers

Abichou, T., Aibright, W., and Benson, C., (2003). Field Tests of Conventional and AlternativeFinal Cover Systems for Landfill Final Covers. SWANA WASTECON 2003 Proc., 143-158.

Abichou, T., Edil, T., Benson, C., Berilgen, M. (2002), Mass Behavior of Soil-Tire Chip Backfill,Beneficial Use of Recycled Materials in Transportation Applications, Air and Waste ManagementAssociation, Sewickley, PA, 689-698. tt

Abu-Hassanein, Z. and Benson, C. (1994), Using Electrical Resistivity for Compaction Control ofCompacted Soil Liners, Proc. Tailings and Mine Waste ‘94, Jan. 19-21, Ft. Collins, CO. 177-189.

Albright, W., Benson, C., Gee, C., Rock, S., and Abichou, T. (2001), Tests of Alternative FinalLandfill Covers in Arid and Semi-Arid Areas Using Innovative Water Balance MonitoringSystems, Proc. 36th Annual Engineering Geologij & Geotechnical Engineering Syinp., 33-41.

Albight, W., Benson, C., Gee, C., and Rock, 5. (2000), Tests of Alternative Final Landfill CoversUsing Innovative Water Balance Monitoring Systems, Proc. Geological Society of America AnnualMeeting, Reno, Nevada, 32(7), 126.

Benson, C. Albright, W., Ray, D., Smegal, J., Robertson, 0, and Gupta, D. (2008). EvaluatingOperational Irregularities at Hanford’s Environmental Restoration Disposal Facility, Proc.Waste Management ‘08, Phoenix, AZ.

Benson, C., Edil, T., Bin-Shafique, 5. (2007), Leaching of Trace Elements from Soils Stabilized withCoal Fly Ash, Proc. Flue Gas Desuiphurization Byproducts at Coal Mines, K. Vories and A.Harrington, Eds., US Dept. of Interior Office of Surface Mining Coal Research Center,Carbondale, IL, 101-111.

Benson, C. (2005), General Report on Technical Session 3a: Waste Disposal and Management,Proc. 16 International Conference on Soil Mechanics and Geotechnical Engineering, JapaneseGeotechnical Society, Tokyo, 179-185.

17


Benson, C., Bohnhoff, G., Apiwantragoon, P., Ogorzalek, A., Shackelford, C, and Albright, W.(2004), Comparison of Model Predictions and Field Data for an FT Cover, Tailings and MineWaste ‘04, Balkema, Leiden, Netherlands, 137-142.

Benson, C. (2000), liners and Covers for Waste Containment, Proc. Fourth Kansai InternationalGeotechnical Forion, Creation of a New Geo-Environment, Japanese Geotechnical Society, Kyoto,japan, 1-40.

Benson, C. (1999), Final Covers for Waste Contaimnent Systems: A North American Perspective,Proc. XVII Cbnference of Geotechnics of Torino, Control and Management of Subsoil Pollutants, ItalianCeotechnical Society, Torino, Italy, 1-32.

Benson, C. (1999), Environmental Ceotechnics in the New Millenium, Geotechnics for DevelopingAfrica, C. Wardle, C. Blight, and A. Fourie, Eds., Balkema, Rotterdam, 9-22.

Benson, C. and Khire, M. (1995), Earthen Materials in Surface Barriers, Barrier Technologies forEnvironmental Management, National Academy Press, National Research Council, D79-D89.

Benson, C., Olson, M., and Bergstrom, W. (1995), Field Evaluation of Five Landfill LinerInsulations, Proc. Eighteenth International Madison Waste Conference, Sept. 23-24, Madison, WI,309-318.

Benson, C. (1994), Research Developments in Clay Liner Construction, Proc. 32nd AnnualInternational Solid Waste Exposition, Solid Waste Association of North America, Silver Spring,MD, 81-93. V

Benson, C., Chamberlain, F., and A. Erickson (1994 Methods for Assessing Freeze-Thaw Damagein Compacted Soil Liners, Proc. Seventeenth International Madison Waste Conference, Madison, WI,Sept. 21-22, 185-197.

Christman, M., Edil, T., and Benson, C. (1999), Characterization of Well Seals Using an UltrasonicMethod, Proc. Symp. On Application of Geophysics to Engineering and Environmental Problems,Environmental arid Engineering Geophysics Society, Wheat Ridge, CU, 879-888. ‘

Benson, C. and Boutwell, G. (1992), Compaction Control and Scale-Dependent HydraulicConductivity of Day Liners, Proc. of the 15th International Madison Waste Conference, Madison,WI, Sept. 23-24, 62-83.

Benson, C., Hardianto, F., Motan, E., and Mussatti, D. (1992), Comparison of Laboratory and InSitu Hydraulic Conductivity Tests on a Full-Scale Test Pad, Mediterranean Conference onEnvironmental Geoteck, Cesme, Turkey, May 25-27, 219-228.

Benson, C. and Othman, M. (1991), Geotechnical Characteristics of Compacted Municipal SolidWaste Compost, Proc. of the 34th Annual Meeting of the Association of Engineering Geologists, Sept.30-Oct. 4, Chicago, IL, 683-691.

18

Craig H. Benson, PhD. PE

Benson, C. (1991), Predicting Excursions beyond Regulatory Thresholds of HydraulicConductivity Using Quality Control Measurements, Proc. of the First Canadian Conference onEnvironmental Geotechnics, Montreal, May 14—17, 447-454. 1i

Benson, C. (1990), A Minimum Thickness of Compacted Soil Liners, of the 13th Annual MadisonWaste Conference, Madison, WI, September 19-20, 395-422.

Benson, C. (1989), Index Tests for Evaluating the Effect of Leachate on a Soil Liner, Proc. SecondInternational Syniposiuin on Environmental Geotechnology, Shanghai, China, 222-228.

Benson, C., Charbeneau, IL, and Daniel, U. (1988), Reliability of Compacted Soil Liners, Proc. ofthe National Conference on Hydraulic Engineering, ASCE, Colorado Springs, Colorado, 564-569.

Elder, C., Benson, C., Eykholt, C. (2001), Economic and Performance Based Design of MonitoringSystems for PRBs, Proc. 2001 International Containment and Remediat ion Conference, Institute forInternational Cooperative Environmental Research, Florida State University, Tallahassee, FL,USA, 1-5.

Erickson, A., Chamberlain, E., and Benson, C. (1994), Effects of Frost Action on Covers and Linersin Cold Environments, Proc. Seventeenth International Madison Waste Conference, Madison, WI,Sept. 21-22, 198-220. t

Foose, C., Tachavises, C., Benson, C., and Edil, T. (1998), Analyzing GeoenvironmentalEngineering Problems with MODFLOW, Proc. MODFLOW ‘98, Colorado School of Mines,Golden, CO. 1,81-88.

Gibson, S., Benson, C., and Edil, T. (1999), Assessing exploratory Borehole Seals with ElectricalGeophysical Techniques, Proc. Symp. On Application of Geophysics to Engineering andEnvironmental Problems, Environmental and Engineering Geophysics Society, Wheat Ridge, CO.869-878.

Gulec, S., Benson, C., and Edil, T. (2003), Effects of Acid Mine Drainage on the EngineeringProperties of Geosvnthetics, Tailings and Mine Waste ‘03, Swets & Zeitlinger, Lisse, 173-179.

Hardianto, P. and Benson, C. (1993), Effect of Specimen Size on Hydraulic ConductivityMeasurement of Compacted Soil Liners, Proceedings ASCE Annual Florida Section Meeting, Sept.9-11, Orlando, 1-12. t2

Hill, T. and Benson, C. (1999), Hydraulic Conductivity of Compacted Mine Rock Backfill, Tailingsand Mine Waste ‘99, Balkema, Rotterdam, 373-379.

Jo, H., Benson, C., and Edil, T. (2004). Long-Term Hydraulic Conductivity and Cation Exchangeof a Geosynthetic Clay Liner (CCL) Permeated with Inorganic Salt Solutions, Proc. 2004 AnnualConference, Korean Society of Soil and Groundwater Environment, Jeonju, Korea, 59-62.

Katsumi, T., Ogawa, A., Numata, S., Benson, C., Kolstad, U., Jo, H., Edil, T., and Fukagawa, R.(2002), Geosynthetic Clay Liners Against Inorganic Chemical Solutions, Proc. Second Japan-KoreaJoint Seminar on Geoenvironmental Engineering, Kyoto University, Japan, 27-32.

19


Katsumi, T., Benson, C., Foose, C., and Karnon, M. (1999), Calculating Chemical Leakage fromLandfill Bottom Liners, Proc. 34” Annual Conference, Japanese Geotechnical Society, Tokyo.

Katsumi, T., Benson, C., Jo, H., and Edil, T. (1999), Hydraulic Conductivity of GCLs Permeatedwith Chemical Solutions, Proc. 54th Annual Conference, Japanese Society of Civil Engineers,Tokyo

Katsumi, T., Benson, C., Foose, G., and Kamon, M. (1999), Performance-Based Method forAnalyzing Landfill Liners, Geoenvironmen [a! Engineering, R. Yong and H. Thomas, Eds., BritishGeotechnical Society, Thomas Telford Publishers, London, 21-28.

Khire, M., Benson, C., Bosscher, P., and Pliska, P. (1994), Field-Scale Comparison of Capillary andResistive Landfill Covers in an Arid Climate, Proc. 14th Annual Hydrology Days, Fort Collins,CO. 195-209.

Kim, H. and Benson, C. (1999), Oxygen Transport Through Multilayer Composite Caps OverMine Waste, Proc. Sudbzrnj ‘99 - Mining and the Environment 11, Centre in Mining and MiningEnvironment Research, Laurentian University, Sudbury, Ontario.

Kumthekar, U., Chiou, J., Prochaska, M., and Benson, C. (2002), Development of Long-TermMonitoring System to Evaluate Cover System Performance, Proc. Waste Management ‘02,Tucson, AZ.

Kumthekar, U., Chiou, J., Prochaska, M., and Benson, C. (2002), Development of Long-TermMonitoring System to Monitor Cover System Conditions, Spectrum 2002, 9th Biennialinternational Conference On Nuclear & Hazardous Waste Management, Reno, Nevada.

Lane, D., Benson, C., Bosscher, P., and Pliska, R. (1992), Construction and HydrologicObservations of Three Instrumented Final Covers, Proc. 15th international Madison WasteConference, Madison, Sept. 23-24, 231-250.

Miller, E., Bahia, H., Benson, C., Khatri A., and Braham, A. (2001), Utilization of Waste FoundrySand in Hot Mix Asphalt Mixtures, American Foundry Society Transactions, 103(1), 1393-1407.

Motan, F., Benson, C., and Edil, T. (1997), Shear Strength of Municipal Solid Waste, Proc.WasteTech ‘97, National Solid Waste Management Assoc., Washington, DC. tfl:

Ogorzalek, A., Shackelford, C., and Benson, C. (2005). Comparison of Model Predictions andField Data for an Alternative Cover in a Semiarid Climate. Symposium on Mines and theEnvironment, Rouyn-Noranda, Quebec, Canada, May 15-18, 2005.

Othman, M. and Benson, C. (1991), Influence of Freeze-Thaw on the Hydraulic Conductivity of aCompacted Clay, Proc. of the 14th Annual Madison Waste Conference, Madison, WI, Sept. 25-26,296-312.

Rashad, S. and Benson, C. (1994), Improving Subsurface Characterization and Prediction ofContaminant Transport, Proc., ASCE Annual Hydraulic Engineering Conference, 277-281.

20


Senol, A., Bin-Shafique, M., Edil, T., and Benson, C. (2002), Use of Class C Fly Ash forStabilization of Soft Subgrade, Proc. 5th International Congress on Advances in CivilEngineering, Istanbul Technical University, Istanbul, Turkey, 963-972. t!

Simon, D., Alumbaugh, D., and Benson, C. (2001), Quantitative Characterization of an lAS AirPlume Using Geophysics, Proc 2001 International Containment and Reinediation Conference,Institute for International Cooperative Environmental Research, Florida State University,Tallahassee, FL, USA, 1-4.

Waugh, W., Albright, W., and Benson, C. (2007), Alternative Covers: Enhanced Soil WaterStorage and Evapotranspiration in the Source Zone, Enhancements to Natural Attenuation:Selected Case Studies, T Early, Ed-, Savannah River National Laboratory, Aiken, SC, 9-15-

Yesiller, N., Benson, C., Edil, T, and Klima, J. (1997), Assessment of Cased-Borehole Seals Usingand Ultrasonic Method, Proc Fifth Great Lakes GeotechnicalfGeoenvironmental Conference, AnnArbor, Michigan, 133-132.

Reviews, Editorials, and Magazine Articles

Albright, W., Benson, C., G. Gee, Abichon, T., Roesler, A., and Rock, S. (2003), Examining theAlternatives, Civil Engineering, 73(1), 70-75.

Benson, C. (2006), Numerical Modeling in Geoenvironmental Practice, Geo Strata, Aug. 2006. t

Edil, T. and Benson, C- (2002), Use of Industrial By-Products as Geo-Materials, Geo Strata, April2002.

Benson, C. (1996), An Overview of Uncertainty ‘96, Geotechnical News, June, 1996.

Benson, C. and Pliska, R. (1996), HELP Needs Help from the Field, Waste Age, March 1996.

Benson, C. and Edil, T. (1995), Using Shredded Scrap Tires in Civil & EnvironmentalConstruction, Resource Recij cling, Oct. 1995.

Benson, C. (1992), Remotely Monitoring Field-Scale Performance of Final Covers, TechnologyReport, Waste Management, Inc, First Quarter 1992. t]

Benson, C. (1990), Waste Geotechnics at the University of Wisconsin-Madison, Geotechnical News,December, 1990, 43-46.

Benson, C. (1990), Review of Clay Liners for Waste Management Facilities, J of Environmental Quality,November 1990.

Edil, T. and Benson, C. (2006), Geotechnical Applications of CCPs in Wisconsin, Ash At Work,American Coal Ash Association, Summer 2004, 16-20. t!l

21


Pedersen, J., McMahon, K., and Benson, C. (2006), Prions: Novel Pathogens of EnvironmentalConcern?, [ of Environmental Engineering, 132(9), 967-969

Reports

Abichou, T., Benson, C., and Edil, T. (1999), Beneficial Reuse of Foundry Byproducts,Environmental Geotechnics Report 99-1, Dept. of Civil and Environmental Engineering,University of Wisconsin-Madison.

Abichou, T., Benson, C., and Edil, T. (1998), Beneficial Reuse of Foundry Sands in Construction ofHydraulic barrier Layers, Environmental Geotechnics Report 98-2 Dept. of Civil andEnvironmental Engineering, University of Wisconsin-Madison. t1

Abichou, T., Benson, C., and Edil, T. (1998), Field Hydraulic Conductivity of Three Test PadsConstructed with Foundry Sands, Environmental Geotechnics Report 98-14, Dept. of Civil andEnvironmental Engineering, University of Wisconsin-Madison.

Acosta, FL, Edil, T, and Benson, C. (2003), Soil Stabilization and Drying Using Ph’ Ash, GeoEngineering Report 03-03, Dept. of Civil and Environmental Engineering, University ofWisconsin-Madison.

Aibright, W. and Benson, C. (2002), Alternative Cover Assessment Program 2002 Annual Report,Publication Na 4H82, Desert Research Institute, Reno, Nevada.

Bareither, C., Benson, C., Bariaz, NI., and Morris, J. (2008), Performance of North AmericanBioreactor Landfills, Office of Research and Development, US Environmental ProtectionAgency, Cincinnati, Ohio.

Bareither, C., Edil, T., and Benson, C. (2007), Determination of Shear Strength Values for GranularBackfill Materials Used by WisDOT, SPR No. 0092-05-08, Wisconsin Highway ResearchProgram, Madison, WI.

Benson, C. (2008), On-Site Disposal Facilities for Department of Energy Sites: Current Status andFuture Implications, Independent Technical Review Committee, US Department of Energy,Washington, DC-

Benson, C., Albright, W., Ray, D., and Smegal, J. (2008), Review of the EnvironmentalManagement Waste Management Facility at Oak Ridge, Independent Technical ReviewCommittee, US Department of Energy, Washington, DC.

Benson, C., Albright, W., Ray, D., and Smegal, J (2008), Review of Issues Associated with theProposed On-Site Waste Disposal Facility (OSWDF) at Portsmouth, Independent TechnicalReview Committee, US Department of Energy, Washington, DC

Benson, C., Albright, W., Ray, D., arid Smegal, J. (2008), Review of Proposed On-Site DisposalFacility at the Paducah Gaseous Diffusion Plant, Independent Technical Review Committee, USDepartment of Energy, Washington, DC.

22


Benson, C., Albright, W., Ray, D., and Smegal, J. (2008), Review of Disposal Practices at theNevada Test Site, Independent Technical Review Committee, US Department of Energy,Washington, DC. t!

Benson, C., Aibright, W., Ray, D., and Smegal, J. (2008), Review of Disposal Practices at theSavannah River Site, Independent Technical Review Committee, US Department of Energy,Washington, DC.

Benson, C., Kucukkirca, 1., and Scalia, J. (2008), Properties of Geosynthetics Exhumed from theSeven Mile Creek Landfill Eau Claire, Wisconsin, Ceo Engineering Report No. 08-22,University of Wisconsin, Madison, Wisconsin.

Benson, C., Albright, W., and Ray, D. (2007), Evaluating Operational Issues at the EnvironmentalRestoration Disposal Facility at Hanford, Independent Technical Review Committee, USDepartment of Energy, Washington, DC.

Benson, C., Albright, W., Ray, D., and Smegal, J. (2007), Review of the Idaho CERCLA DisposalFacility (JCDF) at Idaho National Laboratory, Independent Technical Review Committee, USDepartment of Energy, Washington, DC.

Benson, C., Albright, W., Wang, X., and MacDonald, E. (2006), Assessment of the ACAP TestSections at Kiefer Landfill: Hydraulic Properties and Ceomorphology, Ceo Engineering ReportNo. 02-16, University of Wisconsin, Madison, Wisconsin.

Benson, C., Barlaz, M., Lane, D., and Rawe, J. (2003), State-of-the-Practice Review of BioreactorLandfills, Ceo Engineering Report 03-05, Dept. of Civil and Environmental Engineering,University of Wisconsin-Madison.

Benson, C., Abichou, T., Wang, X., Gee, C., and Albright, W. (1999), Test Section InstallationInstructions — Alternative Cover Assessment Program, Environmental Ceotechnics Report 99-3,Dept. of Civil & Environmental Engineering, University of Wisconsin-Madison.

Benson, C. and Wang, X. (1998), Soil Water Characteristic Curves for Solid Waste, EnvironmentalCeotechnics Report 98-13, Dept. of Civil and Environmental Engineering, University ofWisconsin-Madison.

Benson, C., Albrecht, B., Motan, E., and Querio, A. (1998), Equivalency Assessment for anAlternative Final Cover Proposed for the Greater Wenatchee Regional Landfill and RecyclingCenter, Environmental Geotechnics Report 98-6, Dept. of Civil and Environmental Engineering,University of Wisconsin-Madison.

Benson, C. (1998), Comparison of the Effectiveness of Prescriptive and Alternative Covers: MeadPaper, Escanaba, Michigan, Environmental Ceotechnics Report 98-13 Dept. of Civil andEnvironmental Engineering, University of Wisconsin-Madison.

Benson, C. (1997), A Review of Alternative Landfil] Cover Demonstrations, EnvironmentalCeotechnics Report 97-1, Dept. of Civil and Environmental Engineering, University ofWisconsin-Madison.

23

Craig H. Benson, PhD, PS

Benson, C. and Hill, T. (1997), Results of Field Hydraulic Conductivity Tests Conducted on Mine

Backfill: Flambeau Mine, Environmental Geotechnics Report 97-4, Dept. of Civil and

Environmental Engineering. University of Wisconsin-Madison.

Benson, C. and Wang, X. (1997), Assessment of Green Sands from Wagner Castings Co. as Barrier

Materials for Landfill Covers, Environmental Geotechnics Report 97-8, Dept. of Civil and

Environmental Engineering, University of Wisconsin-Madison.

Benson, C., Bosscher, P., and Jong, D. (1997), Predicting Seasonal Changes in Pavement Stiffness

and Capacity Caused by Freezing and Thawing, Geotechnical Engineering Report 97-9, Dept.

of Civil and Environmental Engineering, University of Wisconsin-Madison.

Benson, C. and Wang, X. (1996), Field Hydraulic Conductivity Assessment of the NCASI Final

Cover Test Plots, Environmental Geotechnics Report 96-9, Dept. of Civil and Environmental

Engineering, University of Wisconsin-Madison.

Benson, C. (1996), Final Cover Hydrologic Evaluation - Project Summary, Environmental

Geotechnics Report 96-4, Dept. of Civil and Environmental Engineering, University of

wisconsin-Madison.

Benson, C. (1994), Assessment of Air Permeability and Freeze-Thaw Resistance of Soils Proposed

for Use in the Final Cover at Greater Wenatchee Regional Landfill, Environmental Geotechnics

Report 94-3, Department of Civil and Environmental Engineering, University of Wisconsin-

Mad ison.

Benson, C and Rashad, S. (1994), Using Co-Kriging to Enhance Hydrogeologic Characterization,

Final Report-Year 2, Environmental Geotechnics Report 94-1, Department of Civil and


Benson, C., Khire, M., and Bosscher, P. (1993), Final Cover Hydrologic Evaluation: Phase 11 - Final

Report, Environmental Geotechnics Report 93-4, Department of Civil and Environmental

Engineering, University of Wisconsin-Madison. t

Benson, C. and Bosscher, P. (1992), Effect of Winter Exposure on the Hydraulic Conductivity of a

Test Pad, Environmental Geotechnics Report 92-8, Department of Civil and Environmental

Engineering, University of Wisconsin- Madison.

Benson, C. (1992), Comparison of In Situ and Laboratory Measurements of Hydraulic

Conductivity on a Test Pad with Construction Defects, Environmental Geotechnics Report 92-7,

Department of Civil and Environmental Engineering, University of Wisconsin- Madison.

Benson, C., Zhai, H., and Rashad, S. (1992), Assessment of Construction Quality Control

Measurements and Sampling Frequencies for Compacted Soil Liners, Environmental

Geotechnics Report 92-6, Department of Civil and Environmental Engineering, University of

Wisconsin- Madison.

24


Benson, C. and Khire, M. (1992), Soil Reinforcement with Strips of Reclaimed HDPE,

Environmental Geotechnics Report 92-5, Department of Civil and Environmental Engineering,

University of Wisconsin- Madison. 7’

Benson, C. and Hardianto, F. (1992), Hydraulic Conductivity Assessment of Compacted Soil

liners: Phase I-Final Report, Environinenta] Geotechnics Report 92-4, Department of Civil and

Environmental Engineering, University of Wisconsin- Madison.

Benson, C. and Cooper, S. (1992), Reducing Uncertainty in Hydraulic Conductivity Using Soil

Classifications from the Cone Penetrorneter - Progress Report for First Quarter of Work,


University of Wisconsin- Madison.

Benson, C. and Lane, D. (1992), Final Cover Hydrologic Evaluation - Review of First Quarter of

Work, Environmental Geotechnics Report No. 92-1, Department of Civil and Environmental


Benson, C. (1991), Quality Assurance and Hydraulic Conductivity Assessment - Review of First

Six Months Work, Environmental Geotechnics Report No. 91-6, Department of Civil and


Benson, C. (1991), Hydrologic Analysis of a Co-Composter Landfill Cell, Environmental

Geotechnics Report No. 91-4, Department of Civil and Environmental Engineering, University

of Wisconsin-Madison.

Benson, C. and Othman, M. (1991), Effect of Freeze-Thaw on the Hydraulic Conductivity of

Compacted Clay, Environmental Geotechnics Report No. 91-3, Department of Civil and


Benson, C. (1991), Minimum Thickness of Compacted Soil liners, Environmental Geotechnics

Report No. 91-2, Department of Civil and Environmental Engineering, University of

Wisconsin-Madison

Benson, C. (1989), A Stochastic Analysis of Water and Chemical Flow in Compacted Soil Liners,

Ph.D. Dissertation, University of Texas at Austin, Austin, Texas, 246p.

Benson, C. (1987), A Comparison of In Situ and Laboratory Measurements of Hydraulic

Conductivity, Geotechnical Engineering Report 87-2 and M.S. Thesis, University of Texas at

Austin, SOp.

Bin-Shafique, S., Edil, T., Benson, C., and Senol, A. (2003), incorporating a Fly Ash Stabilized

Layer into Pavement Design — Case Study, Ceo Engineering Report 03-04, Dept. of Civil and


Bin-Shafique, S., Benson, C., and Edil, T. (2002), Leaching of Heavy Metals from Fly Ash

Stabilized Soils Used in Highway Pavements, Ceo Engineering Report 02-14, Dept. of Civil and


25

Craig 1-1, Benson, PhD, PE

Bolen, M., Roesler, A., Benson, C., and Albright, W. (2001), Alternative Cover Assessment

Program: Phase II Report, Ceo-Engineering Report No. 01-10, University of Wisconsin,

Madison, WI.

Bosscher, P., Jong, D., and Benson, C. (1998), Users Guide for UW Frost, Geotechnical

Engineering Report 98-11 Dept. of Civil and Environmental Engineering, University of

Wisconsin-Madison.

Camargo, F., Edil, T., Benson, C., and Martono, W. (2008), In Situ Stabilization of Gravel Roads

with Fly Ash, Ceo-Engineering Report No. 08-25, University of Wisconsin, Madison, WI.

Chamberlain, F., Erickson, A., and Benson, C. (1997), Frost Resistance of Cover and Liner

Materials for Landfills and Hazardous Waste Sites, Report 97-29, US Army Cold Regions

Research and Engineering Laboratory, Hanover, NH.

Christnian, M., Edil, T., Benson, C., and Riewe, T. (1999), Field Evaluation of Annular Well Seals,

Environmental Geotechnics Report 99-2, Dept. of Civil and Environmental Engineering,

University of Wisconsin-Madison.

Cooper, S. and Benson, C. (1993), An Evaluation of How Subsurface Characterization Using Soil

Classifications Affects Predictions of Contaminant Transport, Environmental Ceotechnics

Report 93-1, Department of Civil and Environmental Engineering, University of Wisconsin

Madison.

Dingrando, J., Benson, C., and Edil, T. (1999), Beneficial Reuse of Foundry Sand in Controlled

Low-Strength Material, Environmental Geotechnics Report 99-5 Dept of Civil and


Edincliler, A., Benson, C., and Edil, T. (1996), Shear Strength of Municipal Solid Waste,



Edil, T. and Benson, C. (2002), Compatibility of Containment Systems with Mine Waste Liquids,

Report No. WRI GRR 01-09, Water Resources Institute, University of Wisconsin-Madison. i

Elder, C., Benson, C, and Eykholt, C. (1998), Air Plume Characterization and Mass Transfer

Modeling for In Situ Air Sparging, Environmental Geotechnics Report 98-3, Dept. of Civil and


Foose, C., Benson, C., Edil, T. (1996), Methods for Evaluating the Effectiveness of Landfill Liners,

Environmental Ceotechnics Report 96-10, Dept. of Civil and Environmental Engineering,


Foose, C., Benson, C., and Edil, T. (1995), Evaluating the Effectiveness of Landfill Uners,

Environmental Ceotechnics Report 95-4, Dept. of Civil and Environmental Engineering,


26


Foose, C., Benson, C., and Bosscher, P. (1993), Shear Strength of Sand Reinforced with Shredded

Waste Tires, Environmental Ceotechnics Report 93-2, Department of Civil and Environmental


Gibson, S., Edil, T., and Benson, C. (1999), Assessing Exploratory Borehole Seals with Electrical

Geophysical Techniques, Environmental Geotechnics Report 99-4 Dept. of Civil and

Environmental Engineering, University of Wisconsin-Madison. 71

Goodhue, M., Edi], T., and Benson, C. (1998), Reuse of Foundry Sands in Reinforced Earth

Structures, Environmental Geotechnics Report 98-12 Dept. of Civil and Environmental

Engineering, University of Wisconsin-Madison. 71

Gurdal, T., Benson, C., and Albright, W. (2003), Hydrologic Properties of Final Cover Soils from

the Alternative Cover Assessment Program, Ceo Engineering Report 03-02, Ceo Engineering

Program, University of Wisconsin-Madison.

Khire, M., Benson, C. and Bosscher, P. (1994), Final Cover Hydrologic Evaluation, Phase Ill

Report, Environmental Geotechnics Report 94-4, Department of Civil and Environmental


Kini, K and Benson, C. (2002), Water Content Calibrations for Final Cover Soils, Ceo Engineering

Report 02-12, Ceo Engineering Program, University of Wisconsin-Madison. 71

Kleven, J., Edil, T., and Benson, C. (1998), Mechanical Properties of Excess Foundry Sand for

Roadway Subgrade, Environmental Geotechnics Report 98-1 Dept. of Civil and Environmental


Klima, J., Edil, T., and Benson, C. (1996), Field Assessment of Monitoring and Water Supply Well

Seals, Environmental Geotechnics Report 96-li, Dept. of Civil and Environmental Engineering,


Kraus, J. and Benson, C. (1994), Effect of Freeze-Thaw on the Hydraulic Conductivity of Three

Paper Mill Sludges: Laboratory and Field Evaluation, Environmental Geotechnics Report 94-6,

Dept. of Civil and Environmental Engineering, University of Wisconsin-Madison.

Kraus, J. and Benson, C. (1994), Laboratory and Field Evaluation of the Effect of Freeze-Thaw on

the Hydraulic Conductivity of Barrier Materials, Environmental Geotechnics Report 94-5,

Department of Civil and Environmental Engineering, University of Wisconsin-Madison.

Lane, D., Benson, C., and Bosscher, p. (1992), Hydrologic Observations arid Modeling

Assessments of Landfill Covers: Phase I-Final Report, Environmental Ceotechnics Report 92-10,

Department of Civil and Environmental Engineering, University of Wisconsin-Madison. 71

Lau, A., Edil, T., and Benson, C. (2001), Use of Ceocells in Flexible Pavements Over Poor

Subgrades, Ceo Engineering Report 01-05, Dept. of Civil and Environmental Engineering,

University of Wisconsin-Madison. 71

27


Lee, T. and Benson, C. (2002), Using Ioundry Sands as Reactive Media in Permeable Reactive

Barriers, Ceo Engineering Report 02-01, Dept. of Civil and Environmental Engineering,


Li, L., Benson, C. and Edil, T. (2005), Assessing Groundwater Impacts from Coal Combustion

Products Used in Highways, Ceo Engineering Report No. 05-22, Departmental of Civil and

Environmental Engineering University of Wisconsin-Madison.

Li, L., Eykholt, C., and Benson, C. (2001), Groundwater Modeling: Semi-Analytical Approaches

for Heterogeneity and Reaction Networks, Groundwater Research Report WRI GRR 01-10,

Water Resources Institute, University of Wisconsin-Madison.

Meer, S. and Benson, C. (2004), U.S. Environmental Protection Agency In-Service Hydraulic

Conductivity of GCLs in Landfill Covers, Geo Engineering Report 04-17, Dept. of Civil and


Meerdink, J. and Benson, C. (1994), Unsaturated Hydraulic Conductivity of Two Compacted

Barrier Soils, Environmental Geotechnics Report 94-6, Department of Civil and Environmental


Mengelt, M., Edil, T., and Benson, C. (2000), Reinforcement of flexible Pavements Using Geocefls,

Ceo Engineering Report 00-4, Dept. of Civil and Environmental Engineering, University of

Wisconsin-Madison.

Nelson, M. and Benson, C. (2002), Laboratory Hydraulic Conductivity Testing Protocols for Paper

Sludges Used for Hydraulic Barriers, Technical Bulletin No. 848, National Council for Air and

Stream Improvement, Research Triangle Park, NC.

Nelson, M. and Benson, C. (2002), Laboratory Hydraulic Conductivity Testing Protocols for Paper

Sludges Used for Hydraulic Barriers, Ceo Engineering Report 02-02, Dept. of Civil and


Palmer, B., Benson, C., and Edil, T. (1995), Hydraulic Characteristics of Class F Fly Ash as a

Barrier Material: Laboratory and Field Evaluation, Environmental Ceotechnics Report 95-8,


Roesler, A., Benson, C., and Albright, W. (2002), Field Hydrology and Model Predictions for Final

Covers in the Alternative Cover Assessment Program — 2002, Ceo Engineering Report 02-08,


Russell, J., Benson, C. and Jeljeli, M. (1990), Use of Monte Carlo Techniques to Enhance Qualifier

1 Contractor Prequalification Model, Technical Report No. 102, Construction Engineering and

Management Program, Department of Civil and Environmental Engineering, University of

Wisconsin-Madison.

Samuelson, M. and Benson, C. (1997), Predicting Frost Depths Beneath Flexible Roadways Using

a Thennal Model, Environmental Ceotechnics Report 97-5, Dept. of Civil and Environmental

Engineering University of Wisconsin-Madison.

28


Sauer, J., Benson, C. and Edil, T. (2005), Metals Leaching from Highway Test Sections

Constructed with Industrial Byproducts, Ceo Engineering Report No. 05-21, Departmental of

Civil and Environmental Engineering, University of Wisconsin-Madison.

Sauer, J., Benson, C. and Edil, T. (2005), Leaching of Heavy Metals from Organic Soils Stabilized

with High Carbon Fly Ash, Ceo Engineering Report No. 05-01, Departmental of Civil and

Environmental Engineering, University of Wisconsin-Madison. .

Tatlisoz, N., Edil, T., Benson, C., Park, J., and Kim, J. (1996), Review of Environmental Suitability

of Scrap Tires, Environmental Geotechriics Report 96-7, Dept. of Civil and Environmental

Engineering, University of Wisconsin-Madison. Note: you may have accidentally skipped this

one

Trast, J. and Benson, C. (1993), Hydraulic Conductivity of Thirteen Compacted Days,



Yesiller, N., Edil, T., and Benson, C. (1994), Ultrasonic Evaluation of Cased Borehole Seals,



Yesiller, N., Edil, T., and Benson, C. (1994), Verification Technique to Evaluate the Integrity of

Well Seals, Environmental Geotechnics Report 94-2, Department of Civil and Environmental


Standards

Benson, C. (2006), Standard D 7243, Standard Guide for Measuring the Saturated Hydraulic

Conductivity of Paper Industry Sludges, Annual Book of Standards, ASTM International, 04.09.

Benson, C., Wang, X. and Kim, H. (2002), Standard D 6836, Test Methods for Determination of the

Soil Water Characteristic Curve for Desorption Using a Hanging Column, Pressure Extractor,

Chilled Mirror Hygrometer, and/or Centrifuge, Annual Book of Standards, ASTM International,

04.09.

Daniel, 0. and Benson, C. (2002), Standard 0 5856, Test Method for Measurement of Hydraulic

Conductivity of Porous Material Using a Rigid-Wall Compaction Mold Permeameter, Annual

Book of Standards, ASTM International, 04.09. Originally approved 1995, Revised 2002.

Ladd, R. and Benson, C. (2000), Standard D 5084, Test Method for Measurement of Hydraulic

Conductivity of Saturated Porous Materials Using a Flexible Wall Permeameter, Annual Book of

Standards, ASTM International, 04.09. Extensive revision in 2000 by R. Ladd and C. Benson.

Originally developed by J. Dunn and D. Daniel.

29


Yesiller, N., Shackelford, C., and Benson, C. (2005), Standard D 7100, Standard Test Method forHydraulic Conductivity Compatibility Testing of Soils with Aqueous Solutions that may AlterHydraulic Conductivity, Annual Book of Standards, ASTM International, 04.09.

SPONSORED RESEARCH

Waste Containment Systems

Coupling Effects of Erosion and Hydrology on the Long-Term Performance of EngineeredSurface Barriers, US Nuclear Regulatory Commission

Predicting the Long-Term Performance of Surface Barriers for LLRW Containment, USDepartment of Energy, Consortium for Risk Evaluation with Stakeholder Participation

Effectiveness of Engineered Covers: From Modeling to Performance Monitoring, US NuclearRegulatory Commission

Bentonite-Polymer Nanocomposites for Geoenvironmental Applications, National ScienceFoundation, with T. Edil and C. Shackelford

Prion Transport in Porous Media: Influence of Electrostatic and Non-DLVO Interactions,National Science Foundation, with J. Pedersen and J. Aiken

Effect of Stress, Hydration, and Ion Exchange on the Hydraulic Conductivity of GeosyntheticClay Liners, Colloid Environmental Technologies Corporation

Innovative Methods for Natural Restoration of Final Covers for Mill Tailings, US Dept. of Energy,with W. Albright and J. Waugh

Evaluating Long-Term Impacts on Final Covers - Exhumation of the ACAP Test Sections,National Science Foundation, US Environmental Protection Agency, Environmental Researchand Education Foundation, with D. Fratta and W. Albright

Toxin/Pathogen Inactivation and Disposal of Intentionally Contaminated Foods, National Centerfor Food Protection and Defense, US Dept. of Homeland Security, with D. Noguera

Predictive Tools for Sustainable Solid Waste Management Using Bioreactor Landfills, NationalScience Foundation, with M. Barlaz

The State of Municipal Solid Waste Bioreactor Landfills-Il, US Environmental Protection Agency,with M. Barlaz

VOC Transport Through Composite Landfill Liners, Groundwater Research Advisory Council,State of Wisconsin, with T. Edil.

VOC Transport in Lined Containment Facilities, Groundwater Research Advisory Council, Stateof Wisconsin, with T. Edil.

30

Craig H Benson, PhD, PE

Hydrology of the Monticello Water Balance Cover, Stollar Corporation and US Dept. of Energy.

Effect of Freeze Thaw on Compacted Soil Liners and Covers, University of Wisconsin Graduate

SchooL

Fate and Transport of Chronic Waste Disease Prions in Municipal Solid Waste Landfills, US

Environmental Protection Agency, with J. Pedersen and J. Aiken

Evaluation of VOC Contamination of Groundwater from Lined Landfills in Wisconsin,

Groundwater Research Advisory Council, State of Wisconsin.

Hydrologic Modeling of Covers Used for Mine Waste Containment, US Environmental

Protection Agency, with C Shackelfor&

Bioreactor Landfills: State of the Practice, US Environmental Protection Agency, with D. Lane

and M. Barlaz.

Field Performance of Alternative Covers, US Environmental Protection Agency.

Integrated Long-Term Stewardship for Low-Level Radioactive Waste, US Department of Energy

and Flour Fernald, Fernald, Ohio.

Chemical Interactions Between Mine Waste Liquids and Geosynihetics, Groundwater Research

Advisory Council, State of Wisconsin, with T. Edil.

Long-term Chemical Compatibility of Geosvnthetic Clay Liners, National Science Foundation,

with C. Shackelford.

Hydraulic Conductivity Testing Protocols for Paper Sludges, National Council of the Pulp and

Paper Industry for Air and Stream Improvement.

Dry Barriers for Waste Containment, National Science Foundation, with S Kung

Alternative Cover Assessment Program, United States Environmental Protection Agency, with

W. Albright (Desert Research Institute) and Glendon Gee (Battelle PNNL).

Large-Scale Verification of a VOC Transport Model for Composite Liners, Groundwater Research

Advisory Council, State of Wisconsin, with T. Edt

Field Assessment of Geosynthetic Clay Liners in Final Covers, United States Environmental

Protection Agency.

Unsaturated Hydraulic Properties of Alternative Cover Soils, Waste Management, Waste

Connections, Bluestem Solid Waste Authority, and Marina Solid Waste Management District

Alternative Covers for Waste Containment in Southern California, San Bernardino County, CA.

Equivalency of SubtitleD and Alternative Earthen Covers, City of Glendale, Arizona

31


Development of WinUNSAT-H, a Windows Implementation of UNSAT-H, WMX Technologies,

inc.

Hydraulic Characterization of Mine Rock Backfill for the Flambeau Mine, Flambeau Mining

Company, Ladvsmith, WI

Hydraulic Characterization of Mine Rock Backfill for the Flambeau Mine: Il-hi Situ Verification,

Flambeau Mining Company, Ladysmith, WI

Field Hydraulic Conductivity Assessment of the NCASI Test Plots, National Council of the Paper

Industry for Air and Stream Improvement

Effect of Freeze-Thaw on the Hydraulic Conductivity of Compacted Papermill Sludge, the

National Council of the Paper Industry for Air and Stream Improvement.

Engineering Properties of Paper Sludges Used for Hydraulic Barriers in Landfill Covers, Solid

Waste Research Program, State of Wisconsin.

Shear Strength of Municipal Solid Waste, WMX Technologies, inc., with T. Edil.

Evaluating the Effectiveness of Landfill Liners, Groundwater Research Advisory Council, State of

Wisconsin, with T. Edil.

Laboratory and Field Evaluation of the Effects of Freeze-Thaw on Barrier Materials, United States

Environmental Protection Agency.

Field-Evaluation of Geoinsulafion-A Geosynthetic Insulation Material, Envotech Limited

Partnership, with P. Bosscher

Hydraulic Conductivity Assessment of Compacted Soil Liners, Waste Management of North

America, Inc.

Rational Construction Quality Control Criteria for Compacted Soil Liners, University of

Wisconsin Graduate School.

Final Cover Hydrologic Evaluation, Waste Management of North America, Inc.

Evaluation of Freezing and Thawing on the Hydraulic Conductivity of a Test Pad, Waste

Management of Wisconsin, Inc.

Improved Design Methods for Landfill Final Covers, National Science Foundation.

Quality Assurance and Hydraulic Conductivity Assessment of Compacted Soil Liners, Waste

Management of North America and Chemical Waste Management, Inc.

Hydrologic Analysis of a Co-Composting Landfill, Solid Waste Research Council, State of

Wisconsin.

32

Craig H. Benson, PhD, PB

Sustainable Construction

Engineering Behavior of Recycled Unbound Materials, US Dept. of Transportation Pooled Fund,with T. Edil.

Recycled Materials Resource Center, Federal Highway Administration and United StatesEnvironmental Protection Agency, with K. Gardner

Assessing Environmental Impacts Associated with Bases and Subgrades Stabilized with CoalCombustion Products, Center for Freight and Infrastructure Research and Education, USDepartment of Transportation, with T. Edil.

User Guidelines for Waste and By-Product Materials in Highway Pavements, US Environmental

Protection Agency, with A. Graettinger and J. Jambeck

Gravel Equivalency of fly Ash Stabilized Reclaimed Roads, Minnesota Local Roads ResearchBoard, with T. Edil

In Situ Stabilization of Gravel Roads with CCPs, Combustion Byproducts Recycling Consortium,US Dept of Energy, with T. Edil

Leaching of Heavy Metals from Gray-Iron Foundry Slags Used in Geo Engineering Applications,Solid Waste Research Council, State of Wisconsin, with T. Edil.

Monitoring and Analysis of Leaching from Subbases Constructed with Industrial Byproducts,FHWA Recyded Materials Research Center, with T. Edil.

Ash Utilization in Low Volume Roads, Minnesota Department of Transportation, with T. Edil

Integrated Approach for Assessing Groundwater Impacts from Fly Ash Stabilized Soils, AlliantEnergy, with T. Edil.

Geoenvironmental Assessment of Soft Soils Stabilized with High Carbon fly Ashes, Solid WasteResearch Program, State of Wisconsin, with T. Edil.

Are High Carbon Fly Ashes Effective Stabilizers for Soft Organic Soils?, National ScienceFoundation, with T. Edil.

Consortium for Beneficial Reuse of fly Ashes, Alliant Energy, Northern States Power, andMineral Solutions, Inc., with T. Edil.

Reuse of Fly Ash for Soil Stabilization, US Dept. of Energy, with T. Edil.

Field Demonstration of Earth Structures Constructed with Soil-Tire Chip Mixtures, Solid WasteResearch Council, State of Wisconsin, with T. Edil.

33


Use of Foundry Sands in Hot Mix Asphalt, University Industrial Relations, with FL Bahia

Fly Ash Stabilization of Soft Subgrades, US Dept of Energy, Mineral Solutions, Inc., and AlliantPower, with t Edil.

Field Demonstration of Beneficial Reuse of Foundry Byproducts in Highway Subgrade,

Wisconsin Department of Transportation, with T. EdiL

Properties of Foundry Sand Relevant to Design of Embankments and Retaining Wall Backfill,

State of Wisconsin, Recycling Market Development Board, with T. Edil.

National Practice Survey: Beneficial Re-use of Waste Foundry Sands, State of Wisconsin

Recycling Market Development Board, with T. EdiL

Using Waste Foundry Sands as Hydraulic Barriers, Solid Waste Research Council, State ofWisconsin, with t EdiL

Field Assessment of Barrier Layers Constructed with Foundry Sands, Solid Waste ResearchCouncil, State of Wisconsin, with T Edil.

Use of Shredded Waste Tires in Highway Construction, United States Environmental ProtectionAgency, with T. Edil.

Sub-base Replacement with Waste Foundry Sands, State of Wisconsin, Recycling MarketDevelopment Board, with T. EdiL

Using High Carbon Class F Fly Ash as a Lining Material: 1-Laboratory Study, Solid WasteResearch Council, State of Wisconsin, with EL Edil.

Using High Carbon Class F Fly Ash as a Lining Material: 11-Field Verification, Solid WasteResearch Council, State of Wisconsin, with T. Edil.

Reinforcement of Soils with Shredded Waste Tires, Solid Waste Research Council, State ofWisconsin, with P. Bosscher.

Use of Reclaimed Waste HDPE as Soil Reinforcement, Solid Waste Research Council, State ofWisconsin.

Groundwater Remediation and Monitoring

Sorption and Transport of Polycyclic Aromatic Hydrocarbons in Organoclays used for PermeableAdsorptive Barriers, CH2M Hill Inc. and Union Pacific Inc.

Environmental Impacts of Engineered Nanomaterials, Nanoscale Science and EngineeringCenter, National Science Foundation, with). Pedersen and It Hammers

34


Cray-Iron Foundry Slags as a Reactive Medium for Removing Arsenic from Ground Waler and

Drinking Water, Groundwater Research Advisory Council, State of Wisconsin, with D. Blowes.

Innovative Treatment of COPR Wastes in Costal Areas, US Dept. of Transportation, with T. Edil.

Development of Large-Scale Application for Remediation of Chromium Ore Processing Residue,

University Industrial Relations, University of Wisconsin, with T. Edil.

An Integrated Approach to Evaluating Environmental Impacts from Soils Stabilized with Fly

Ashes, State of Wisconsin Recycling Program and Alliant Energy, Inc.

Uncertainty Based Design of Permeable Reactive Barriers, Wisconsin Ground Water Research

Advisory Council, with C. Eykholt

lrtnovative Groundwater Treatment: Reactive Wails Constructed with Excess Foundry Sand,

Wisconsin Groundwater Research Advisory Council, with C. Evkholt.

Development of Integrated Decision Support System for Welihead Protection, Wisconsin Water

Resources Council, State of Wisconsin.

Reducing Uncertainty in Subsurface Characterization, U.S. Department of Energy.

Ultrasonic Probe to Evaluate the Integrity of Borehole Seals, Federal Highway Administration,

with T. Edil.

Field Assessment of Monitoring Well Seal Integrity, Groundwater Research Advisory Council,

State of Wisconsin, with T. Edil.

A Tool For Evaluating the Integrity of Monitoring Well Seals, Groundwater Research Advisory

Council, State of Wisconsin, with T. Edil.

Characterization of Air Plumes and Modeling Mass Removal During In Situ Air Sparging,

Groundwater Research Advisory Council, State of Wisconsin, with G. Eykholt.

Other Topics

Wisconsin-Puerto Rico Partnership for Research and Education in Materials LWi(PR)EMI, USNational Science Foundation, with J. de Pablo, J. Pedersen, et aL

Fate and Transport of Chronic Waste Disease Prions in Waste Water Treatment Plants, US

Environmental Protection Agency

A Modular Geoenvironmental Curriculum, National Science Foundation, with other faculty from

Wisconsin, Northwestern, Michigan, and Argonne National Laboratory.

Stiffness and Stress State in Unsaturated Soils, Minnesota Department of Transportation, with T.

Edil.

35


Thermal Conditions Below Highway Pavements During Winter, Wisconsin Department of

Transportation, with P. Bosscher.

Design Protocols for Cellular Confinement with Geoweb, University Industrial Relations and

Presto Products, Appleton, WI, with T. Edil.

Equivalency of Subgrade Improvement Methods, Wisconsin Department of Transportation, with

T. Edil.

Reinforcement of Soft Subgrades with Geosynthetics, Wisconsin Department of Transportation,

with T. Edil.

Evaluation of the DCP and SSG for Subgrade Evaluation, Wisconsin Department of

Transportation, with T. Edil.

Shear Strength of Granular Backfill Materials, Wisconsin Department of Transportation, with T.

Edil.

Correlating Index Properties and Engineering Behavior of Wisconsin Soils, Wisconsin

Department of Transportation, with T. Edil.

incorporating Alternative Subgrade Improvement Methods in Pavement Design, Wisconsin

Department of Transportation, with T. Edil.

GRADUATE STUDENTS SUPERVISED

PhD Students

Breitmeyer, R., Dissertation Topic Hydrology of Bioreactor Landfills, expected 2010, co-advised

with T. Edil, expected 2010.

Bareither, C., Dissertation Topic: Settlement of Bioreactor Landfills, co-advised with T. Edil,

expected 2010.

Komonwèeraket, K., Dissertation Topic: Mechanisms Controlling Release of Trace Elements from

Soils Stabilized with Fly Ash, co-advised with T. Edil, expected 2008.

Park, M., Dissertation Topic: Transport of VOCs in Composite Landfill Liners, co-advised with T.

Edil, expected 2009.

Apiwantragoon, P., Dissertation Topic: Alternative Covers: Field Performance and Modeling

Methods, 2007.

Tinjum, J., Dissertation Topic: Innovative Remedial Treatment of Chromium Ore Processing

Residues, co-advised with T. Edil, 2006.

36


Albright, W., Dissertation Topic: Field Performance of Landfill Covers, 2005.

Un, L., Dissertation Topic: Impacts of Mineralogical Fouling of Permeable Reactive Barriers in

Heterogeneous Environments, 2004

Chang, R, Dissertation Topic: Geophysical Characterization of Water and Solute Movement in an

Arid Climate, 2003, co-advised with D. Alumbaugk

Kim, W., Dissertation Topic: Alternative Subgrades Stabilization with Geosynthetics, 2003, co

advised with T. Edil.

Guiec, S., Dissertation Topic: Compatibility of Geosynthetics and Mine Waste Liquids, 2003, co

advised with T Edil.

Tanyu, B., Dissertation Topic: Equivalency of Alternative Subgrade Stabilization Methods. 2003,

co-advised with t EdiL

Jo, H., Dissertation Topic: Fundamental Factors Affecting Interactions Between Bentortite and

Inorganic Liquids, 2003.

Bin-Shafique, S., Dissertation Topic: Leading of Heavy Metals from Fly Ash Stabilized Soils,

2002, co-advised with T. Edil.

Chalermyanont, T., Dissertation Topic: Reliability Analysis of Mechanically Stabilized Earth

(MSE) Walls, 2002.

Lee, T., Dissertation Topic: Using Waste Foundry Sands as Reactive Media in Permeable Reactive

Barriers, 2002.

Albrecht, B., Dissertation Topic: Passive Dry Barriers: Air Circulation and Mass Transfer, 2001.

Elder, C, Dissertation Topic: Effect of Heterogeneity on Performance of Permeable Reactive

Barriers, 200(1

Kim, FL, Dissertation Topic: Oxygen Transport Through Mu]ti-layer Caps Over Mine Waste,

2000.

Abichou, T, Dissertation Topic: Hydraulic Properties of Foundry Sands, 1999, co-advised with E

EdiL

Tachavises, C., Dissertation Topic Flow Rates Past Vertical Groundwater Cut-Off Walls:

Intluentia] Factors and Their impact on Wall Selection, 1998.

Foose, G., Dissertation Topic: Leakage Rates and Chemical Transport Through Composite

Landfill LIners, 1997, co-advised with T. Edil.

Khire, M., Dissertation Topic: Field Hydrology and Water Balance Modeling of Earthen Final

Covers for Waste Containment, 1995

37


Yesiller, N., Dissertation Topic: Ultrasonic Evaluation of Cased Borehole Seals, 1994, co-advised

with T. Edil.

Othmari, M., Dissertation Topic: Effect of Freeze/Thaw on the Structure and Hydraulic

Conductivity of Compacted Clays, 1992.

MS Students

Schlicht, P., Thesis Topic: Weathering-Induced Alterations in the Hydraulic Properties of Final

Covers for Waste Containment, 2009, co-advised with J. Tinjum.

Scalia, J., Thesis Topic Hydraulic Conductivity of Geosynthetic Day Liners Used in Composite

Final Covers, 2009.

Bradshaw, S., Thesis Topic: Effects of Stress, Hydration, and Ion Exchange on Geosynthetic Clay

Liners, 2008.

Camargo, F., Thesis Topic: Equivalency of Fly-Ash Stabilized RPM and Gravel Base Course, 2008,

co-advised with T. Edil.

Rauen, T., Thesis Topic: Effect of Bioreactor Leachate on Geosynthetic Clay Liners, 2007.

Cope, U., Thesis Topic: Treating TCE-Contaminated Groundwater with Gray-Iron Slag, 2007.

Metz, S., Thesis Topic: Gray-Iron Slags as a Reactive Medium for Arsenic Treatment, 2007.

Eberhardt, M., Thesis Topic: Leaching of Heavy Metals from Gray-Iron Slags with and without

Carbonation, 2008.

Baugh, J., Thesis Topic Fly Ash Stabilization of Gravelly Soils, 2008, co-advised with T. Edil.

Rosa, M., Thesis Topic: Effect of Preeze-Thaw Cycling on Resilient Modulus of Fly-Ash

Stabilized Subgrade Soils,2006, co-advised with T. Edil.

Klett, N., Thesis Topic Evaluation of VOC Discharges to Groundwater from Engineered Landfills

in Wisconsin, 2005, co-advised with T. EdIL

Bareither, C., Thesis Topic: Geological Controls on the Shear Strength of Wisconsin Sands, 2006,


Bohnhoff, C, Thesis Topic: Predicting the Water Balance of Alternative Covers Using UNSAT-H,

2005.

Sauer, J., Thesis Topic: Leaching of Heavy Metals from Organic Soils Stabilized with High Carbon

Fly Ashes, 2005, co-advised with T. EdiL

38

Craig H Benson, PhD, PE

Tastan, 0., Thesis Topic: Stabilizing Organic Soils with High Carbon Fly Ashes, 2005, co-advised

with t Edil.

Trzebiatowski, B., Thesis Topic: Fifed of Pedogenesis on Soil Water Characteristic Curves of

Cover Soils, 2004.

Meer, S., Thesis Topic: Effects of Ion Exchange and Desiccation on CCLs used in Final Covers,

2003.

Gurdal, T., Thesis Topic: Unsaturated Hydraulic Properties of Alternative Cover Soils, 2003.

Kim, K, Thesis Topic: Water Content Reflectometer Calibrations for Final Cover Soils, 2002.

Camaciho, L, Thesis Topic: Analysis of Landfill Failure Using Three-Dimensional Limit

Equilibrium Methods, 2002, co-advised with T. EdiL

Roesler, A., Thesis Topic: Field Hydrology and Mode) Predictions for Final Covers in the

Alternative Assessment Program, 2002.

Acosta, H., Thesis Topic: Stabilization of Soft Subgrade Soils Using Fly Ash, 2002, co-advised

with T. Edil.

Lanier, A-, Thesis Topic: VOC Transport in Geosynthetic Clay Liners, 2002.

Marchesi, 1., Thesis Topic: Simulating the Hydrology of Alternative Covers with Soil Cover, 2002.

Mergener, E., Thesis Topic: Assessing Clogging of Permeable Reactive Barriers in Heterogeneous

Aquifers Using a Geochemical Model, 2002.

Rochford, W., Thesis Topic: Effectiveness of Geomembrane and Soil-Bentonite Cut-Off Walls,

2002.

Thorstad, P., Thesis Topic: Field Performance of a Geosynthetic Clay Liner (CCL) Used as the

Hydraulic Barrier Layer in a Landfill Cover in Southwestern Wisconsin, 2002.

Nelson, M., Thesis Topic: Laboratory Hydraulic Conductivity Testing Protocols for Paper

Sludges in Barrier Layers, 2001.

Lau, W., Thesis Topic: Use of Ceocells in Flexible Pavements Over Poor Subgrades, 2001, co


Simon, D., Thesis Topic: Comparison of Three Geophysical imaging Techniques for

Characterization of an lAS Plume, 2001, co-advised with D. Alumbaugh.

Kolstad, D., Thesis Topic Hydraulic Conductivity and Ion Exchange in GCLs Permeated with

Multispecies Inorganic Solution, 2000.

39


Mengelt, M., Thesis Topic Effect of Cellular Confinement on Soil Stiffness Under Dynamic

Loads, 2000, co-advised with T. EdiL

Maxwell, S., Thesis Topic: Geosynthetic Reinforcement of Soft Subgrades, 1999, co-advised with

T. Edil.

Jo, H., Thesis Topic: Chemical Compatibility of Non-Prehydrated GCLs and Inorganic Liquids,

1999.

Lee, T., Thesis Topic; Physical Modeling of Vertical Groundwater Cut-Off Walls, 1999.

Gibson, S, Thesis Topic: Geoelectric Methods to Evaluate Borehole Seals, 1999, co-advised with T.

Edil.

Winkler, W., Thesis Topic: Thickness of Monolithic Covers in Arid and Semi-arid Climates, 1999.

Chen, C., Thesis Topic: Meteorological Conditions for Design of Monolithic Alternative Earthen

Final Covers (AEFCs), 1999.

Vasko, 5.. Thesis Topic: Hydraulic Conductivity of Prehydrated Geosynthetic Clay Liners

Permeated with Calcium Chloride Solutions, 1999.

Dingrando, J., Thesis Topic; Benefidal Reuse of Foundry Sands in Controlled Low Strength

Material, 1999, co-advised with T. Edil.

Beurmann, S., Thesis Topic: Dielectric Sensor for Measuring Suction in Dry Soils, 1999.

Chiang, 1., Thesis Topic: Effect of Fines and Gradation on Soil Water Characteristic Curves of

Sands, 1998.

Christinan, M., Thesis Topic Annular Well Seals: A Geophysical Study of Influential Factors and

Seal Quality, 1999, co-advised with T. Edi].

Lin, L.C., Thesis Topic; Effect of Wet-Dry Cycling on Swelling and Hydraulic Conductivity of

Geosynthetic Gay Liners, 1998.

Goodhue, M., Thesis Topic: Reuse of Foundry Sands in Reinforced Earthen Structures, 1998, co.


jong, D., Thesis Topic: Load Limit Timings for Roadways Exposed to Frost, 1997, co-advised with

P. Bosscher.

Suwansawat, V., Thesis Topic: Using TM? for Moiswre Movement in Clays, 1997.

Akpinar, M., Thesis Topic: Interface Shear Strength of Geomembranes and Geotextiles at

Different Temperatures, 199T

40


Gavin, M., Thesis Topic Physical and Chemical Effects of Electroosmosis on Kaolinite, 1997, co

advised with T. EdiL

Kircher, J., Thesis Topic Modeling Chemical and Physical Effects of Electro-osmosis on Kaolinile,


Kieven, J., Thesis Topic: Mechanical Properties of Excess Foundry System Sand and an

Evaluation of its use in Roadway Structural Fill, 1997, co-advised with T. Edil.

Hill, T., Thesis Topic: Field and Laboratory Hydraulic Conductivity of Compacted Mine Waste

Rock, 1997.

Elder, C., Thesis Topic: Modeling Mass Transfer During In Situ Air Sparging, 1996.

Baker, D., Thesis Topic: Physical Modeling of In Situ Air Sparging, 1996.

Klima, j., Thesis Topic Field Assessment of Monitoring and Water Supply Well Seals, 1996, co


Tinjum, J, Thesis Topic: Soil Water Characteristic Curves for Compacted Fine Grained Soils,

1995.

Payne, L., Thesis Topic: Use of Pulsating Elect-ro-Osmosis in Barrier Applications, 1993, co

advised with T Edil.

Tatlisoz, N, Thesis Topic: Using Tire Chips in Earthen Structures, 1995, co-advised with T Edil.

Palmer, B., Thesis Topic: High Carbon Class F Fly Ash for Reactive Barrier Landfill Liners, 1995,


Albrecht, B., Thesis Topic: Effect of Desiccation on Hydraulic Conductivity of Compacted Clays,

1995.

Harrick, M., Thesis Topic: Permeable Reactive Walls in Wisconsin, 1994.

Abu Hassaneth, 1, Thesis Topic: Using Electrical Resistivity Measurement as a Quality Control

Tool for Compacted Cay Liners, 1994.

Meerdink, J, Thesis Topic Unsaturated Hydraulic Conductivit of Barrier Soils Used for Final

Covers, 1994.

Pekarun, 0, Thesis Topic: Evaluation of Hydraulic Significance of Defects in Annular Well Seals,


Kraus, J., Thesis Topic: Hydraulic Conductivity of Papermill Sludges, 1994

Wang, X., Thesis Topic Evaluating Suction Head at the Wetting Front During Infiltration in

Compacted Clays, 1993.

41


Foose, C., Thesis Topic: Shear Strength of Sand Reinforced with Shredded Waste Tires, 1993.

Cooper, S., Thesis Topic: An Evaluation of How Subsurface Characterization Using Soil

Classifications Affects Predictions of Containment Transport, 1993.

Bashel, M., Thesis Topic: Flow Rates in Composite Landfill Liners, 1993.

Trast, J., Thesis Topic: Field Hydrauiic Conductivity of Thirteen Compacted Clay Liners, 1993.

Genthe, D., Thesis Topic Shear Strength o Two Pulp and Paper Mill Sludges with Low Solids

Content, 1993.

Sajjad, M., Thesis Topic: Effect of Electro-Osmosis on Hydraulic Conductivity of Compacted

Clay, 1993.

Abichou, T., Thesis Topic Field Evaluation of Geosynthetic insulation for Protection of Clay

Liners, 1993.

Bahner, E., Thesis Topic Soil Nailing Case Histories in Wisconsin, 1993.

Hardianto, F., Thesis Topic: Representative Sample Size for Hydraulic Conductivity of

Compacted Clay, 1993.

Lane, D., Thesis Topic: Hydrologic Observations and Modeling Assessments of Landfill Covers,

1992.

PATENTS

Apparatus and Method for Testing the Hydraulic Conductivity of Geologic Materials, United

Stales Patent No. 6,178,808.

Pressure Plate Extractor, United States Patent No. 6,718,835.

CONSULTING ENGINEERING EXPERIENCE

Dr. Benson has served as a consultant on more than 90 projects for government and industry in

the United States and abroad. His consulting work includes specialty design and analysis, peer

review, prototype and field testing of new technologies, forensic engineering, and litigation

support. References provided on request.

42


RECENT INVITED LECTURES

Final Covers for Waste Containment: Lessons Learned from a Nationwide Field Experiment.

Sowers State-of-the-An Lecture, 12th Annual George F. Sowers Symposium, Georgia institute of

Technology, Atlanta, Georgia, May 2009.

Chemical Alterations and Their Impact on the Hydrologic Properties of Bentonite, Monash

University, Melbourne, Victoria, Australia, December 2008.

Hydrology and Settlement in Bioreactor Landfills, Cutting Edge Technological Advances in Design

and Operation, Reducing Leachate Quantity, Spatial Needs, and Costs, and Accelerating Landfill Gas

Rccoven, Rates, World Bank, Washington, DC, November 2007.

Modeling Unsaturated Flow and Atmospheric interactions, Keynote Speaker, Second International

Conference on Mechanics of Unsaturated Soils, Weimar, Germany, March 2007.

Geosynthetic Clay Liners for Waste Containment: Panacea or Future Problem?, Geosynthetic

Research institute, Drexel University, Philadelphia, November 2005.

Effects of Heterogeneity on Mineral Fouling of Permeable Reactive Barriers, 2” International

Conference on Reactive Barriers, Belfast Northern Ireland, March 2004.

Lessons Learned from North American Failures, Keynote Speaker, Fifth International Conference on

Environmental Geotechnics, ISSMGE, Rio de Janeiro, Brazil, August 2002.

Waste Containment Systems: Strategies and Perfonnance, Keynote Speaker, GeoEnvironnzent

2902, Australian-New Zealand Geomechanics Society, Newcastle, NSW, Australia, Nov. 2001

Engineered Barriers, Keynote Speaker, National Academy of Sciences, Washington, DC, July

2001.

Are Geosynthetic Clay Liners Effective Barriers for Waste Containment?, Desert Research

Institute, Reno, Nevada, January 2001.

Solid Waste Containment Systems, Keynote Speaker (with M. Manassero), GeoEng200(J,

Melbourne, Australia, November 2000.

Liners and Covers for Waste Containment, Keynote Speaker, Fourth Kansai International

Geotechnical Forum, Creation of a New Geo-Environment, Japanese Geotechnical Society,

Kyoto, Japan, June 2000

EDITORSI-IIPS

Editor-in-Chief, ASCE Journal of Geolechnical and Geoenvironnzental Engineering, 2004-2006

Editor, ASCE Journal of Geotechnical and Geoenvironmental Engineering, 1996-99

43


Editor, lournal of Geotext lies and Geoinembranes, 2009-present.

Co-Editor, Waste Containment and Reinediation, GSP Na 142, ASCE, A. Alshawabkeh et al., coeditors, 2005.

Editor, Risk-Based Corrective Action and Brownfieids Restorations, CS!’ No. 82, ASCE, J. Meegoda, R.Gilbert, and S. Clemence, co-editors, 1998

Co-Editor, Environmental Ceolechnics Section, Geotechnical News, 1994-96

DIRECTORSHIPS AND CHAIRMANSHIPS

Chair, Independent Technical Review Committee for On-Site Disposal Facilities, US Departmentof Energy, March 2007-present.

Director, Wisconsin Geotechnics Laboratory, University of Wisconsin-Madison, December 2000-present.

Co-Director, Consortium for Fly Ash Use in Geotechnical Engineering, University of Wisconsin-Madison, with T. Edil, December 1999-present.

SOCIETY MEMBERSHIPS

Ceo-Institute of the American Society of Civil EngineersBoard of Governors (2007-present)Geoenvironmental Engineering Committee (1990-Present, chair 1996-99)Technical Publications Committee (1993-99, 2004-2006)TPCC Subcommittee on Policies for Specialty Conferences (1997-99)Editor-in-Chief, JGGE, 2004-06, Editor JGGE, 1996-99C-I Magazine Task Force (1997-99)Awards (chair, 1999-2001)

American Society for Testing and Materials (ASTM)D18 Executive Committee (2006-present)Dl 8.04 - Hydrologic Properties of Soil & Rock (1991-Present chair 1996-2006)D18.l 9- Frozen Soil & Rock (1992-Present)

American Geophysical UnionBritish Geotechnical AssociationCanadian Geotechnical SocietyInternational Geosynthetics SocietyNational Ground Water AssociationNorth American Geosynthetics SocietySoil Science Society of America

44


UNIVERSITY SERVICE

Chairman, Geological Engineering, (2007-2008, 2009-present)

Academic Council, Dept. of Civil and Environmental Engineering (1994-99, Chair 1997-99)

Admissions Chairman, Ceo Engineering Program (1990-2006)

Associate Chair of Civil and Environmental Engineering - Environmental Science and

Engineering Division (2004-2007)

Becker Award Committee (chair), Civil and Environmental Engineering (2002-04)

Byron Bird Award Committee (1995)

Civil and Environmental Engineering Salary Committee (1998,2002,2004-2006)

College of Engineering Academic Planning and Curriculum Committee (1996-99)

College of Engineering Advisory Board for Geological Engineering (1990-2008)

College of Engineering Curriculum Committee (1997-99,2002-04)

College of Engineering Diversity Committee (2002-04)

Conflict of Interest Oversight Committee, University of Wisconsin (2000-02)

Graduate Committee, Geological Engineering (1999-present, Chair 1999-2001,2003-2006)

Scholarship Committee, Dept. of Civil and Environmental Engineering (1998-2002)

Search Committee for Ceo Engineering Position (Chairman, 2004-present)

Search Committee for Engineering Geophysics Position (Chairman, 1997-98,2003-04)

Undergraduate Committee, Geological Engineering (Chairman, 2002-2008)

45

Documents

Clinton.pdf | US EPA ARCHIVE DOCUMENTglacial clay tlls with intermitt°efcjt.10’.,._ •, tj’ — 1. this regional geologic cross sec11on is based on information from on—site