U.S. Department of the Interior 

U.S. Geological Survey

Ground-Water Quality in Geauga County, 

Ohio—Review of Previous Studies, 

Status in 1999, and Comparison of 1986 

and 1999 Data 

By Martha L. Jagucki and Robert A. Darner

Water-Resources Investigations Report 01-4160

In cooperation with the

Geauga County Planning Commission and Board of County Commissioners
U.S. Department of the Interior 

Gale A. Norton, Secretary

U.S. Geological Survey 

Charles G. Groat, Director 

Any use of trade, product, or firm names is for

descriptive purposes only and does not imply

endorsement by the U.S. Government.

For additional information write to:

District Chief

U.S. Geological Survey

6480 Doubletree Avenue

Columbus, OH 43229-1111

Copies of this report can be purchased from:

U.S.Geological Survey

Branch of Information Services

Box 25286

Denver, CO 80225-0286

2001
Contents III

CONTENTS

Abstract ................................................................................................................................................................................. 1

Introduction .......................................................................................................................................................................... 2

Purpose and Scope ...................................................................................................................................................... 2

Acknowledgments ....................................................................................................................................................... 2

Description of Study Area .................................................................................................................................................... 2

Water Use .................................................................................................................................................................... 4

Land Use and Population ............................................................................................................................................ 4

Hydrogeologic Setting ................................................................................................................................................ 5

Previous Studies .................................................................................................................................................................... 13

Methods of Study .................................................................................................................................................................. 16

Ground-Water Quality .......................................................................................................................................................... 19

Suitability of Water for Drinking ................................................................................................................................ 20

Bacteria ............................................................................................................................................................. 20

Volatile Organic Compounds ........................................................................................................................... 20

Nitrate and Nitrite ............................................................................................................................................. 20

Esthetic Considerations .................................................................................................................................... 20

Age of Ground Water .................................................................................................................................................. 21

Stratigraphic Variation in Water Quality ..................................................................................................................... 24

Glacial Deposits ................................................................................................................................................ 26

Pottsville Formation ......................................................................................................................................... 26

Cuyahoga Group ............................................................................................................................................... 32

Berea Sandstone ............................................................................................................................................... 33

Controls on Water Quality .......................................................................................................................................... 33

Geochemical Processes ..................................................................................................................................... 33

Anthropogenic Effects ...................................................................................................................................... 34

Nitrate ............................................................................................................................................................ 34

Total Coliform Bacteria ................................................................................................................................ 36

Chloride-to-Bromide Ratios .......................................................................................................................... 36

Temporal Variations in Water Quality ......................................................................................................................... 40

Summary and Conclusions ................................................................................................................................................... 44

References Cited ................................................................................................................................................................... 46

Appendix A: Quality Assurance/Quality Control ................................................................................................................ 56

FIGURES

1-4. Maps showing:

1. Location of wells sampled for water-quality analysis in 1999, Geauga County, Ohio......................................... 3

2. Land use in Geauga County, Ohio, 1975 .............................................................................................................. 6

3. Land use in Geauga County, Ohio, 1996 .............................................................................................................. 7

4. Population density in Geauga County, Ohio, 1990 ............................................................................................... 8

5. Generalized geologic section of Geauga County, Ohio.............................................................................................. 10

6-7. Maps showing:

6. Ground-water levels and direction of flow in the Pottsville Formation and glacial deposits, 

Geauga County, Ohio, September 6-9, 1994......................................................................................................... 11

7. Ground-water levels and direction of flow in the Berea Sandstone, Geauga County, Ohio, 

September 6-9, 1994.............................................................................................................................................. 12
IV Contents

8. Graph showing estimated annual mean tritium concentration, corrected for radioactive decay 

through 1999, in precipitation that fell in northeastern Ohio, 1953 to 1983 ............................................................. 22

9. Graph showing tritium concentrations in ground water and well depth in Geauga County, Ohio, 

June and July 1999 .................................................................................................................................................... 23

10. Trilinear diagram of chemical differences in stratigraphic units showing major cation and anion 

percentages for samples collected in Geauga County, Ohio, June and July 1999..................................................... 25

11. Boxplots of chemical constituents delineated by stratigraphic units for the 1999 sampling in 

Geauga County, Ohio................................................................................................................................................. 27

12. Boxplots of the distance from the water table to the top of the open interval, by stratigraphic units 

for ground-water samples collected in Geauga County, Ohio, 1999......................................................................... 32

13. Graph showing nitrate and total coliform concentrations and depth to the top of the open interval 

from land surface for ground-water samples collected in Geauga County, Ohio, 1999............................................ 35

14. Binary mixing curves for chloride to bromide (Cl:Br) ratios, Geauga County, Ohio, 1999 ..................................... 37

15. Graph showing chloride concentrations and depths of wells sampled in Geauga County, Ohio, 1999 .................... 39

16. Graph showing chloride concentration and distance of well from road for samples collected in 

Geauga County, Ohio, 1999....................................................................................................................................... 41

17. Boxplots of chemical constituents at 16 wells sampled in 1986 and 1999, Geauga County, Ohio........................... 43

TABLES

1. Estimated water-use data for Geauga County, Ohio, 1995 ....................................................................................... 4

2. Land-use comparison between 1975 and 1996 for Geauga County, Ohio ............................................................... 5

3. Summary of stratigraphic units and associated water-bearing properties, Geauga County, Ohio ............................ 9

4. Physical characteristics of wells sampled in Geauga County, Ohio, June and July 1999 ........................................ 18

5. Chemical characteristics of water samples collected in Geauga County, Ohio, June and July 1999 ....................... 49

6. Concentration limits defined by primary and secondary public drinking-water regulations and 

implications for domestic water use and ground-water geochemistry for selected properties and 

chemical constituents in water samples collected in Geauga County, Ohio, June and July, 1999 ............................ 53

 7. Summary ground-water-quality statistics for waters from 16 wells sampled in 1986 and 1999, 

 Geauga County, Ohio ............................................................................................................................................... 42

A1. Chemical characteristics of selected quality-control samples collected in Geauga County, 

Ohio, June and July, 1999 ......................................................................................................................................... 58

CONVERSION FACTORS, VERTICAL DATUM, AND ABBREVIATIONS

Temperature is given in degrees Celsius (°C), which can be converted to degrees Fahrenheit (°F) by use of the following equation:

°F = 1.8(°C) + 32

Sea level: In this report, “sea level” refers to the National Geodetic Vertical Datum of 1929 (NGVD of 1929)—a geodetic datum derived 

from a general adjustment of the first-order level nets of both the United States and Canada, formerly called Sea Level Datum of 1929.

Multiply By To obtain

Length

inch (in.) 25.4 millimeter

 foot (ft) 0.3048 meter

mile (mi) 1.609 kilometer

acre 0.4047 square hectometer

square mile (mi2

) 2.590 square kilometer

gallon (gal) 3.785 liter

cubic foot per second (ft3/s) 0.02832 cubic meter per second

cubic foot per day (ft3

/d) 0.02832 cubic meter per day

gallon per minute (gal/min) 0.06309 liter per second

million gallons per day 0.04381 cubic meter per second
Contents V

Abbreviated water-quality units used in this report: Water volumes and chemical concentrations referred to in water-quality discussions 

are given in metric units. Volume is given in milliliters (mL). Chemical concentration is given in milligrams per liter (mg/L), micrograms 

per liter (μg/L), or milliequivalents per liter (meq/L). Milligrams per liter is a unit expressing the concentration of chemical constituents in 

solution as weight (milligrams) of solute per unit volume (liter) of water. One thousand micrograms per liter is equivalent to one milligram 

per liter. For concentrations less than 7,000 mg/L, the numerical value is approximately the same as for concentrations in parts per million. 

Milliequivalents per liter is the concentration in milligrams per liter divided by the equivalent weight of the ion of interest.

Specific conductance of water is expressed in microsiemens per centimeter at 25 degrees Celsius (μS/cm). This unit is equivalent to 

micromhos per centimeter at 25 degrees Celsius (μmho/cm), formerly used by the U.S. Geological Survey.

Tritium concentration is expressed in tritium units (TU). One tritium unit is equal to one tritium atom per 1018 hydrogen atoms; in terms of 

radioactivity, it is equivalent to 3.24 picocuries per liter. 

Concentrations of bacteria are given as number of colonies per 100 milliliters of sample (col/100 mL).

Pore size of filters is given in micrometers (μm).

Other abbreviations used in this report:

MCL Maximum Contaminant Level

NWQL National Water Quality Laboratory

OEPA Ohio Environmental Protection Agency

SMCL Secondary Maximum Contaminant Level

SVOC Semivolatile organic compound

USEPA U.S. Environmental Protection Agency

USGS U.S. Geological Survey

VOC Volatile organic compound
Abstract 1

Ground-Water Quality in Geauga County, Ohio—Review 

of Previous Studies, Status in 1999, and Comparison of 

1986 and 1999 Data

By Martha L. Jagucki and Robert A. Darner 

ABSTRACT 

Most residents in Geauga County, Ohio, rely on 

ground water as their primary source of drinking 

water. With population growing at a steady rate, 

the possibility that human activity will affect 

ground-water quality becomes considerable. This 

report presents the results of a study by the U.S. 

Geological Survey (USGS), in cooperation with 

the Geauga County Planning Commission and 

Board of County Commissioners, to provide a 

brief synopsis of work previously done within the 

county, to assess the present (1999) ground-water 

quality, and to determine any changes in groundwater quality between 1986 and 1999. 

Previous studies of ground-water quality in 

the county have consistently reported that manganese and iron concentrations in ground water in 

Geauga County often exceed the U.S. Environmental Protection Agency (USEPA) Secondary 

Maximum Contaminant Level (SMCL). Road salt 

and, less commonly, oil-field brines and volatile 

organic compounds (VOCs) have been found in 

ground water at isolated locations. Nitrate has not 

been detected above the USEPA Maximum Contaminant Level (MCL) of 10 milligrams per liter 

as N; however, nitrate has been found in some 

locations at levels that may indicate the effects of 

fertilizer application or effluent from septic systems.

Between June 7 and July 1, 1999, USGS 

personnel collected a total of 31 water-quality 

samples from wells completed in glacial deposits, 

the Pottsville Formation, the Cuyahoga Group, 

and the Berea Sandstone. All samples were analyzed for VOCs, sulfide, dissolved organic carbon, major ions, trace elements, alkalinity, total 

coliforms, and Escherichia coli bacteria. Fourteen 

of the samples also were analyzed for tritium. 

Water-quality data were used to determine 

(1) suitability of water for drinking, (2) age of 

ground water, (3) stratigraphic variation in water 

quality, (4) controls on water quality, and (5) temporal variation in water quality. 

Water from 16 of the 31 samples exceeded 

the Geauga County General Health District’s 

standard of 0 colonies of total coliform bacteria 

per 100 milliliters of water. Esthetically based 

SMCLs were exceeded in the indicated number of 

wells for pH (8), sulfate (1), dissolved solids (3), 

iron (19), and manganese (18). Hydrogen sulfide 

was detected at or above the detection limit of 

0.01 milligram per liter in 17 of the 31 water samples.

A range of water types was found among 

and within the four principal stratigraphic units. 

The waters can be categorized in three groups 

based on predominant anion type: bicarbonatetype waters, chloride-type waters, and sulfatetype waters.
2 Ground-Water Quality in Geauga County, Ohio

Chloride-to-bromide ratio analyses indicate 

that water from 8 of the 31 wells is in some way 

affected by human activity. Five other samples 

were in a chloride-to-bromide ratio range that 

could indicate possible effects of human activity.

Ground-water-quality data from the current 

study were compared to data collected in 1986. 

Statistical analyses of data from the 16 wells that 

were sampled in both years did not indicate any 

significant changes that could be attributed to 

human activity.

INTRODUCTION

The population in Geauga County increased by 

10.5 percent from 1990 to 1999 (U.S. Census Bureau, 

2000). Greater residential development and population 

density brings greater potential for human effects on 

water quality (Ekchardt and Stackelberg, 1995; 

Thomas, 2000). This potential for water-quality 

changes is of critical concern in Geauga County, 

where 98 percent of the residents rely on ground water 

as their source of drinking water (U.S. Geological Survey, 1995). Most of the population (78 percent) is 

served by self-supplied domestic wells (U.S. Geological Survey, 1995); regular water-quality testing of 

such wells is not mandated by local, State, or Federal 

government regulations, which address only public 

water suppliers serving 25 or more people.

In addition, the condition of septic systems that 

are more than 20 years old may be a potential problem, 

especially where systems are not maintained by 

removal of solids from the septic tank about once 

every 3 years (Ohio State University Extension [no 

date]). Failure of septic systems can cause pollution 

that infiltrates to shallow ground water and (or) runs 

off to lakes and streams (Michigan State University 

Extension, 1998; Schwartz and others, 1998; Arnade, 

1999). Because most wastewater in the county is 

treated by septic systems, the potential for effects on 

ground-water quality is considerable. 

To address potential concerns about groundwater quality in Geauga County and to evaluate 

anthropogenic effects (that is, the effects of human 

activities) on ground-water resources, the USGS, in 

cooperation with the Geauga County Planning Commission and Board of County Commissioners, 

assessed water quality in the county in 1999 and compared these data to water-quality data collected by the 

USGS in 1986 and to data collected by previous 

researchers.

Purpose and Scope

The purpose of this report is to review and 

briefly summarize nearly two decades of groundwater-quality data in Geauga County, describe the current (1999) status of ground-water quality in the 

county, and determine whether changes in water quality have occurred since wells were last sampled by 

USGS personnel in 1986. To obtain data on current 

ground-water quality, the USGS collected 31 groundwater samples from June 7 through July 1, 1999, from 

the glacial deposits, the Pottsville Formation, the 

Cuyahoga Group, and the Berea Sandstone. Results of 

the water-quality analyses are presented. The current 

status of water quality is examined in terms of suitability of water for drinking, ground-water age, stratigraphic variation in ground water, and anthropogenic 

influences on ground-water quality. 

Acknowledgments

The authors and the Geauga County Planning 

Commission and Board of County Commissioners 

gratefully acknowledge the support from the Geauga 

County Water Resources Department and the City of 

Akron Public Utilities Bureau in this investigation. 

The authors also thank the 31 homeowners who 

allowed USGS personnel to collect water samples 

from their wells, as well as the Geauga County officials who provided geographic information systems 

(GIS) data regarding roads and land use. Appreciation 

is extended to Mike Bolis, who provided information 

on previous site-specific studies of ground-water quality in the county done by the Ohio Environmental Protection Agency.

DESCRIPTION OF STUDY AREA

Geauga County is in northeastern Ohio, east of 

the Cleveland metroplex (fig. 1). It encompasses an 

area of approximately 409 mi2. The region consists of 

gently rolling hills, with local relief rarely more than 

200 ft. Lowest and highest elevations in the county are 

about 860 ft (southeast of the village of Parkman) and 

about 1,360 ft above sea level (near villages of Chardon and Burton). Draining the county are the headwaters of the Chagrin, Cuyahoga, and Grand Rivers.
Description of Study Area 3

0

5 10

5

0 KILOMETERS

MILES

81 7 30 ο ’ ” 81 15 00 ο

’ ”

41 37 30 ο’ ”

41 22 30 ο

’ ”

41 30 00 ο ’ ”

81 22 30 ο ’ ”

Cleveland

LaDue

Reservoir

East

Branch

Reservoir

Grand

River

East

Branch

Cuyahoga River

West

B

ar nch Cuyah a og

Rvi er

Cuy a a

g ho

River

River

Chagrin

Thompson

Hambd Montville en

Huntsburg

Munson Claridon

Chester

B

Middlefield

urton Newbury

Russell

Parkman

Troy

Auburn

Bainbridge

Chardon

Base from U.S. Geological Survey

1:24,000 Digital Data and 1:24,000 mylar

Albers Equal-Area Conic projection

Standard parallels 30ο

50' and 41ο10', central meridian -84ο

Middlefield

Burton

Chardon

South Russell

Parkman

Figure 1. Location of wells sampled for water quality analysis in 1999, Geauga County, Ohio.

GE-341

GE-355

GE-101

GE-103

GE-202

GE-157

GE-185A GE-104

GE-204

GE-280

GE-147

GE-349A

GE-108

GE-234 GE-109

GE-120

GE-235

GE-85A GE-119

GE-321

GE-126

GE-141

GE-151 GE-165

GE-23

GE-122

GE-228

GE-174A

GE-332

GE-77

GE-159

A

A'

EXPLANATION

Glacial deposits

Cuyahoga Group

Berea Sandstone

Pottsville Formation

GE-101

GE-109

GE-103

GE-120

A A' Trace of geologic section -- generalized section from Eberts and others, 1990.

Ground-water quality site and well identification number

MAIN MARKET RD.

6

CHARDON RD.

G.A.R. HIGHWAY

MAD SON I RD.

O

LD STATE RD.

RAVEN NA RD.

MAYFI ELD RD.

KINSMAN RD.

WASHINGTON ST.

528

528

McFarland's Corner

306

422

422

44

608

322

306

44

322

6

608
4 Ground-Water Quality in Geauga County, Ohio

Average annual precipitation at the National 

Weather Service station in the Village of Chardon, 

Ohio, for the period 1945–99 was 45.74 in.1 Much of 

this precipitation is snowfall, with the annual average 

during 1945–99 being 102.8 in. as unmelted snowfall 

(Jon Burroughs, Midwest Climatic Data Center, written commun., 1999). This is the highest snowfall rate 

in Ohio (Harstine, 1991). Precipitation falls most 

heavily in the northern part of the county (Baker, 

1964).

Water Use

Ground water is of great importance in Geauga 

County, as indicated by water-use data compiled by 

the USGS (1995) (table 1). These data show that, during 1995, self-supplied ground water for domestic use 

accounted for 73 percent of total ground-water use in 

the county and that self-supplied ground water was the 

source of drinking water for almost 80 percent of the 

population. Ground water that was publicly supplied 

(by utilities serving 25 people or more) for domestic 

use accounted for 7 percent of total ground-water use 

and was the drinking-water source for 20 percent of 

the population. 

These data indicate that only 20 percent of the 

county’s population is safeguarded by mandatory periodic testing of water quality and safe drinking-water 

standards, which apply only to public-supply utilities 

as defined above. No periodic testing is required for 

private (self-supplied) domestic wells. The only 

requirement mandated by the State of Ohio and the 

Geauga County General Health District for a private 

well is that the well water be tested for total coliform 

bacteria when the well and the rest of the water system 

is initially installed. If a problem is later suspected, the 

well owner may voluntarily request testing by the 

Geauga County General Health District.

Land Use and Population

Land-use data for the years of 1975 and 1996 

show that residential and commercial areas in Geauga 

County increased from 24,000 to 41,400 acres and 

from 800 to 2,800 acres, respectively (table 2). Forested lands increased in area from 105,000 to 139,000 

acres, mostly because the 1996 analysts counted residential yards as forested area. 

1This precipitation value is the total of liquid and melted frozen precipitation.

Table 1. Estimated water-use data for Geauga County, Ohio, 1995

[Modified from U.S. Geological Survey, 1995; Mgal/d, million gallons per day; --, not applicable]

Water-use category

Ground-water 

withdrawals, in 

Mgal/d

Surface-water 

withdrawals, in 

Mgal/d 

Total

Water withdrawals, 

in Mgal/d

Population 

served

Public-supplied domestica

a

Public-supplied domestic usage includes utilities serving 25 or more people. Withdrawals were estimated from the total water 

withdrawals by public water suppliers in Geauga County, as reported in the Water Withdrawal Facility Registration Program for 1995, 

Ohio Department of Natural Resources. Total withdrawals were multiplied by a U.S. Geological Survey derived coefficient of 35 

percent for domestic use.

0.50 0.00 0.50 b

16,850

b

Population served by water suppliers was estimated using a database called the Model State Information System—Active Community 

Public Water Supply, April 8, 1991, Ohio Environmental Protection Agency, adjusted on the basis of U.S. Department of Commerce 

1995 census data.

Self-supplied domesticc

c

Self-supplied domestic use was estimated as the rural population (computed as the total population minus the number of people served 

by public suppliers) multiplied by 75 gallons per day per person.

4.95 .10 5.05 67,410

Otherd

d

Includes commercial, livestock, irrigation, and public-supplied commercial and industrial use, as well as public use and distributionsystem losses. Descriptions of estimation methodology are on file at the Columbus, Ohio, office of the U.S. Geological Survey.

1.37 .83 2.20 --

Total water withdrawals 6.82 .93 7.75 84,260
Description of Study Area 5

Table 2. Land-use comparison between 1975 and 1996 for Geauga County, Ohio

[Land use data from Ohio Department of Natural Resources, Division of Real Estate and Land Mangement; modified by Geauga County

Planning Commission]

1975 1996

Land-use type Area

(acres)

Percentage of 

total land

Area

(acres)

Percentage of 

total land

Residential 24,000 9.2 41,400 15.9

Commercial 800 .3 2,800 1.1

Industrial 1,000 .4 1,100 .4

Agricultural 63,400 24.3 51,500 19.7

Recreational 2,900 1.1 2,400 .9

Vacant 49,800 19.1 10,000 3.8

Institutional 1,000 .4 2,700 1.0

Forested 105,000 40.2 139,000 53.3

Mined lands 700 .3 1,000 .4

Water and marshes 12,400 4.8 9,100 3.5

During this time, the area of lakes, rivers, streams, and 

marshes decreased from 12,400 acres to 9,100 acres, 

and the area of vacant land dropped from 49,800 acres 

to 10,000 acres (acreage extracted from land-use data 

furnished by the Geauga County Planning Commission, 1999; see figs. 2 and 3). Most of the urban area is 

in the western half of the county and the more agricultural area is in the eastern half of the county, as shown 

in figures 2 and 3.

According to the U.S. Census Bureau, the residential population for Geauga County in 1950 was 

26,646 (U.S. Census Bureau, 1998). The number of 

people residing in Geauga County grew to 47,573 in 

1960 and 62,977 in 1970. The population continued to 

grow at a steady rate of about 1 percent per year during 1970–99, when the total population reached 

89,598. The townships of Chester, Russell, and Bainbridge and the southeast corner of Chardon Township 

are the most densely populated areas (fig. 4). Population growth has necessitated the installation of about 

550 new domestic water wells and sewage-disposal 

systems in the county each year (Geauga County General Health District, 1997).

Hydrogeologic Setting

The bedrock surface in Geauga County consists 

of eroded sedimentary units dipping to the south at 10 

to 20 ft/mi, overlain by glacial sediment from 3 to 

400 ft in thickness (Baker, 1964). A detailed description of bedrock and glacial geology of Geauga County 

is given by Baker (1964) and Eberts and others (1990). 

Glacial geology of the county is further described by 

Totten (1988). Directions of ground-water flow were 

studied by Nichols (1980), Eberts and others (1990), 

and Jagucki and Lesney (1995). Stratigraphy of the 

geologic units underlying the county is summarized in 

table 3. The water-bearing properties of each unit as 

described in table 3 indicates that the units primarily 

used for ground-water supply in the county are the glacial deposits, Pottsville Formation, Cuyahoga Group, 

and Berea Sandstone. A geologic section showing erosional features of the units is given in figure 5. 

The Chagrin Shale, the Cleveland Member of 

the Ohio Shale, and the Bedford Shale (known collectively as pre-Berea sedimentary rocks) are the oldest 

units that are exposed in the study area. These units 

crop out along the sides and bottoms of valleys, but in 

most places they are completely covered by glacial 

deposits, which buried preglacial valleys. The preBerea units are poorly permeable, and wells completed 

in these units frequently have yields too low to meet 

the demands of domestic water supply (Baker, 1964). 

The deltaic and shallow marine deposits known 

as the Berea Sandstone overlie the pre-Berea units. 

Although the Berea Sandstone underlies much of 

Geauga County, it is not used for water supply 

throughout most of the county because it is too deeply 

buried to be developed economically. The Berea Sandstone is used for water supply near areas where it 

crops out along the northern, eastern, and western 

edges of the county. Much of the water produced from 
6 Ground-Water Quality in Geauga County, Ohio

0

5 10

5

0 KILOMETERS

MILES

81 7 30 ο’ ” 81 15 00 ο

’ ”

41 37 30 ο ’ ”

41 22 30 ο ’ ”

41 30 00 ο

’ ”

81 22 30 ο ’ ”

Land-use data from Ohio Department of Natural Resources

Division of Real Estate & Land Management;

modified by Geauga County Planning Commission, 1999.

Base from U.S. Geological Survey

1:24,000 Digital Data and 1:24,000 mylar

Albers Equal-Area Conic projection

Standard parallels 30ο

50' and 41ο10', central meridian -84ο

Urban land (includes residential, 

 commercial, industrial, and institutional)

Recreational

Barren land (includes mined and vacant)

Forested

Water and marshes

Agricultural

EXPLANATION

Land-use type

Figure 2. Land use in Geauga County, Ohio, 1975.
Description of Study Area 7

0

5 10

5

0 KILOMETERS

MILES

Figure 3. Land use in Geauga County, Ohio,1996.

Land-use data from Ohio Department of Natural Resources

Division of Real Estate & Land Management;

modified by Geauga County Planning Commission, 1999.

Urban land (includes residential, 

 commercial, industrial, and institutional)

Recreational

Barren land (includes mined and vacant)

Forested

Water and marshes

Agricultural

81 7 30 ο ’ ” 81 15 00 ο

’ ”

41 37 30 ο ’ ”

41 22 30 ο ’ ”

41 30 00 ο

’ ”

81 22 30 ο ’ ”

Base from U.S. Geological Survey

1:24,000 Digital Data and 1:24,000 mylar

Albers Equal-Area Conic projection

Standard parallels 30o

50' and 41o10', central meridian -84o

EXPLANATION

Land-use type
8 Ground-Water Quality in Geauga County, Ohio

81 7 30 ο ’ ” 81 15 00 ο

’ ”

41 37 30 ο ’ ”

41 22 30 ο

’ ”

41 30 00 ο

’ ”

81 22 30 ο ’ ”

Population less than 25 people per square mile

25 to 49 people per square mile

50 to 124 people per square mile

Greater than 250 people per square mile

125 to 249 people per square mile

EXPLANATION

Figure 4. Population density in Geauga County, Ohio, 1990.

Population distribution modified from U.S. Department

 of Commerce, Bureau of the Census, 1990. 

Base from U.S. Geological Survey

1:24,000 Digital Data and 1:24,000 mylar

Albers Equal-Area Conic projection

Standard parallels 30ο

50' and 41ο10', central meridian -84ο

Water quality site and well identification number for

GE-101 wells sampled by the U.S. Geological Survey in 1999

Water-quality data also collected 

in 1986 (Eberts and others, 1990)

5

0

10

5

0 KILOMETERS

MILES

Thompson

Montville

Chardon Hambden

Huntsburg Munson Claridon Chester

Middlefield

Burton

Newbury

Russell

Parkman Troy

Auburn

Bainbridge

GE-341

GE-355

GE-101 GE-103

GE-202 GE-157 GE-185A

GE-104

GE-204

GE-280

GE-147

GE-349A

GE-108

GE-234 GE-109

GE-120

GE-235

GE-85A GE-119

GE-321

GE-126 GE-141

GE-165 GE-151

GE-23

GE-122

GE-228

GE-174A

GE-332

GE-77

GE-159
Description of Study Area 9

Table 3. Summary of stratigraphic units and associated water-bearing properties, Geauga County, Ohio

[Modified from Eberts and others, 1990; >, greater than]

System Geologic unit

Approximate 

maximum 

thickness (feet)

Character of deposits Water-bearing properties

Quaternary 

(Pleistocene)

Glacial deposits 400 Clay, silt, sand, and gravel; 

deposited by ice and meltwater.

Locally productive aquifer.

Pennsylvanian Pottsville Formation:

Homewood Sandstone Member

Mercer Member

Connoquenessing Sandstone

 Member

Sharon Member

200 Sandstone; contains local 

channels of conglomerate and 

some shale where not removed 

by erosion.

Productive aquifer; most 

extensively developed aquifer in 

Geauga County.

Mississippian Cuyahoga Group:

Meadville Shale

Sharpsville Sandstone

Orangeville Shale

250 Shale and sandstone; 

interbedded; fine grained.

Leaky confining unit on a 

regional scale; poorly productive 

aquifer on a local scale.

Mississippian Berea Sandstone 70 Quartz sandstone; relatively 

well sorted.

Productive aquifer; yields more 

water at shallow depth than 

where it is deeply buried.

Mississippian and 

Devonian

Pre-Berea sedimentary rocks:

Bedford Shale

Cleveland Member of the Ohio Shale

Chagrin Member of the Ohio Shale

>500 Shale Poorly permeable; usually does 

not meet demands of domestic 

use.

wells completed in the Berea Sandstone comes from 

flow through fractures (Baker, 1964). 

Overlying the Berea Sandstone is the Cuyahoga 

Group. This group originated as interbedded, shallow 

marine shales and sandstones; and because of their 

poor permeability, they are treated as one hydrologic 

unit. The Cuyahoga Group is exposed widely, particularly in the eastern part of the county. Even though the 

unit is poorly productive, it is commonly used for 

domestic water supply where more permeable, shallower deposits are absent. 

 In areas where it has not been removed by erosion, the Pottsville Formation overlies the Cuyahoga 

Group. The Pottsville Formation caps the hilltops in 

the northern part of the county, underlies most areas in 

the southern part of the county, and is the most extensively developed aquifer in the county. The Pottsville 

Formation is divided, from oldest to youngest, into the 

Sharon Member (consisting of a conglomerate unit 

overlain by a shale unit), the Connoquenessing Sandstone, the Mercer Shale, and the Homewood Sandstone Members. Because of erosion, the Mercer Shale 

and Homewood Sandstone Members are absent in 

most areas of the county. The Connoquenessing Sandstone Member has also been eroded in the northern 

part of the county and thus is limited mostly to the 

southern half of the county (Baker, 1964). 

Yields of wells completed in the Pottsville Formation are lower in the southern half of Geauga 

County than in the northern half. This difference in 

yield from south to north may be due to the relative 

thickness of the shale unit of the Sharon Member in 

southern Geauga County (which may limit recharge to 

the underlying conglomerate unit) and its thinness or 

absence in northern Geauga County (Baker, 1964). 

Most of the bedrock in Geauga County is covered by unconsolidated glacial deposits that range in 

thickness from about 3 to 400 ft. Glacial deposits are 

used widely for domestic water supply where they 

contain large amounts of sand and gravel. The highest 

yielding wells that tap the glacial deposits are in buried glacial valleys that were filled with a mixture of 

clay, silt, sand, and gravel by glacial meltwater (Jagucki and Lesney, 1995). Buried-valley locations in the 

county are depicted in Eberts and others (1990). Confined ground water can be found where poorly permeable ice-lain silt and clay deposits overlie sand and 

gravel deposits. Wells that tap confined ground water 

(usually located near the base of hills) often flow without being pumped (Baker, 1964).

Potentiometric-surface maps (figs. 6 and 7) constructed by Jagucki and Lesney (1995) indicate no 

major inflow of ground water to Geauga County from 

surrounding areas. Also, gain-loss studies done by the 

USGS in 1980 (unpublished data on file at the USGS 
10 Ground-Water Quality in Geauga County, Ohio

01234 6 5

0 1 23 456

MILES

KILOMETERS

VERTICAL SCALE GREATLY EXAGGERATED

DATUM IS SEA LEVEL

Undifferentiated glacial deposits

Pottsville Formation

Cuyahoga Group

Berea Sandstone

Pre-Berea sedimentary rocks Mississippian

and Devonian

Mississipian

Pennsylvanian

Quaternary

EXPLANATION

1,400

1,300

1,200

1,100

1,000

900

800

700

600

500

1,400

1,300

1,200

1,100

1,000

900

800

700

600

500

FEET FEET East Brach Chagrin River Chagrin River West Branch Cuyahoga River East Branch Cuyahoga River

A A'

Figure 5. Generalized geologic section of Geauga County, Ohio (from Eberts and others, 1990).

Trace of section A-A' is shown on figure 1.

office in Columbus, Ohio), show that the streams in 

the county are all gaining streams (that is, they receive 

discharge from ground-water sources rather than lose 

water to the ground-water system). Thus, virtually all 

ground water within the county originates as precipitation within the county. Most of the precipitation runs 

off into streams or is lost to the atmosphere through 

evaporation and (or) transpiration by plants. Pettyjohn 

and Henning (1979) used base-flow separation of 

stream hydrographs to estimate that 2 to 8 in. of precipitation per year reaches the water table in Geauga 

County. 

In places where bedrock crops out or is covered 

only by glacial deposits, recharge occurs by infiltration of precipitation. Ground water in the surficial glacial deposits and Pottsville Formation generally flows 

from the uplands toward adjacent streams and buried 

valleys (fig. 6). Primary areas of ground-water discharge include the Cuyahoga River, Chagrin River, 

and Grand River and their tributary streams (Jagucki 

and Lesney, 1995). 

Where rocks of the Cuyahoga Group and the 

Berea Sandstone are covered by the Pottsville Formation, recharge occurs as downward flow through the 

overlying formation(s). The predominant direction of 

ground-water flow in the Cuyahoga Group is vertically downward from the Pottsville Formation to the 

Berea Sandstone (Eberts and others, 1990). Groundwater flow within the Berea Sandstone is principally 

horizontal and radial outward from Hambden and 

Claridon Townships (fig. 7). Water from the Berea 

Sandstone discharges to glacial deposits filling buried 

valleys that cut completely through the Berea Sandstone, such as are found in Chardon, Chester, Munson, 

and Russell Townships and along the western edge of 
Description of Study Area 11

0

5 10

5

0 KILOMETERS

MILES

81 7 30 ο ’ ” 81 15 00 ο

’ ”

41 37 30 ο’ ”

41 22 30 ο’ ”

41 30 00 ο ’ ”

81 22 30 ο ’ ”

Cleveland

Base from U.S. Geological Survey

1:24,000 Digital Data and 1:24,000 mylar

Albers Equal-Area Conic projection

Standard parallels 30ο

50' and 41ο10', central meridian -84ο

Water-table contours modified from 

Jagucki and Lesney, 1995

LaDue

Reservoir

East

Branch

Reservoir

Grand

River

East

Branch

Cuyahoga River

West

B

ar nch Cuyah a og

Rvi er

Cuy a a

g ho

River

River

Chagrin

Thompson

Ham Montville bden

Huntsburg

Mun

Claridon

son

Chester

Middlefield

Burton Newbury

Russell

Parkman

Troy

Auburn

Bainbridge

Chardon

12

0

0

1 2

0 0 1 2 0 0

1 0 5 0

1 0 0 0

1 1 0 0

1 15 0

1 1 5

0

1 1 5

0

1 1 0 0

1 1 0 0

1 0 5 0

1 10 0

1150

1200

1 0 5 0

1 0

5

0

1 0

0 0

1 2 5 0 1 2

0

0

1 1 5 0

1 1 5

0

1 0 5 0

1 5 0

1 2 0 0

1 2 0

0

1 1 0 0 1 1 0

0

1 1 0

0

10 5 0 1 0 0 0

1 1 5 0

11 50

9 5

0

950

Figure 6. Ground-water levels and direction of flow in the Pottsville Formation and glacial

deposits, Geauga County, Ohio, September 6-9, 1994.

EXPLANATION

1250 WATER-TABLE CONTOUR --Shows altitude of water table. 

Dashed where inferred. Contour interval 50 feet.

GENERALIZED DIRECTION OF GROUND-WATER FLOW

1250

1250

1
12 Ground-Water Quality in Geauga County, Ohio

0

5 10

5

0 KILOMETERS

MILES

81 7 30 ο ’ ” 81 15 00 ο

’ ”

41 37 30 ο’ ”

41 22 30 ο’ ”

41 30 00 ο ’ ”

81 22 30 ο ’ ”

Cleveland

Base from U.S. Geological Survey

1:24,000 Digital Data and 1:24,000 mylar

Albers Equal-Area Conic projection

Standard parallels 30ο

50' and 41ο10', central meridian -84ο

Water-table contours from Jagucki and Lesney, 1995

LaDue

Reservoir

East

Branch

Reservoir

Grand

River

East

Branch

Cuyahoga River

West

B

ar nch Cuyah a og

Rvi er

Cuy a a

g ho

River

River

Chagrin

Thompson

Ham Montville bden

Huntsburg

Munson

Claridon

Chester

Middlefield

Burton Newbury

Russell

Parkman

Troy

Auburn

Bainbridge

Chardon

Figure 7. Ground-water levels and direction of flow in the Berea Sandstone,

Geauga County, Ohio, September 6-9, 1994.

EXPLANATION

1150 WATER-TABLE CONTOUR --Shows altitude of water table. 

Dashed where inferred. Contour interval 50 feet

GENERALIZED DIRECTION OF GROUND-WATER FLOW

1 0 0 0

1 0 0

0

1 0

0

0

1 0 5 0

1 0 5 0

1 0 5 0

10 5 0

1 1 0 0

1 1 0 0

110 0

1 1 5 0

1000

9

5

0

9 5 0

900

APPROXIMATE LOCATION OF BEREA SANDSTONE OUTCROP

OR SUBCROP BENEATH GLACIAL DEPOSITS -- From Eberts and

others, 1990, pl. 1
Previous Studies 13

the county. Ground water also discharges from the 

Berea Sandstone at outcrop areas along the northern 

and eastern edges of the county (Jagucki and Lesney, 

1995).

PREVIOUS STUDIES 

Previous studies of ground-water quality in Geauga 

County have been done for various purposes and at 

various scales. These studies, when considered jointly 

with the data obtained from the current (1999) study, 

provide an extensive data base of ground-water quality 

in the county. 

Baker and others (1989) completed a statewide 

study of nitrate in private wells that included data from 

132 domestic wells in Geauga County. All samples 

were collected by well owners on the same day in June 

1988 from a cold-water tap near the well. Well owners 

were instructed to run the tap for 3 minutes prior to 

sampling and to preferably select a tap that was not 

affected by any type of in-home water-treatment system. Samples were refrigerated between collection and 

analysis except while in transit to the laboratory. All 

132 wells that were sampled in Geauga County contained nitrate concentrations below the U.S. Environmental Protection Agency (USEPA) Maximum 

Contaminant Level (MCL)2

 of 10 mg/L as nitrogen 

(N). Nitrate concentrations of less than 0.3 mg/L — 

assumed by the researchers to represent natural, background levels — were found in 75 of the 132 sampled 

wells in Geauga County. Concentrations from 0.3 to 

3.0 mg/L were detected in 39 of the 132 sampled 

wells; according to Baker and others (1989) these values may or may not indicate anthropogenic effects. 

Concentrations of 3.0 to 10 mg/L were found in 18 of 

the 132 sampled wells and may indicate anthropogenic 

effects on water quality, such as fertilizer application 

to cropland and lawns, septic-system effluent, or proximity to feedlots.

Lesney (1992) examined the causes of spatial 

variability in ground-water chemistry in the glacial 

aquifers of the Cuyahoga River Basin, which is predominantly in Geauga, Portage, Summit, and Cuyahoga Counties. Thirty-four ground-water samples and 

22 surface-water samples were collected from November 1987 to January 1988 as part of Lesney’s study. 

These samples were analyzed for temperature, pH, 

specific conductance, Eh, major ions, alkalinity, 

nitrate, iron, manganese, and strontium. Lesney’s data 

were combined with numerous ground-water-chemistry data from other locations in the Cuyahoga River 

Basin, obtained from unpublished Master’s theses and 

USGS files. Ground-water data within the boundaries 

of Geauga County consisted of 12 samples from 

USGS files, as reported by Nichols (1980) and Eberts 

and others (1990), and 7 samples collected by Lesney 

from wells completed in the glacial deposits.

Lesney found that ground water in the glacial 

deposits of the upper Cuyahoga River Basin (which 

includes part of Geauga County) was relatively uniform, chemically unevolved water of calcium-magnesium bicarbonate type, with a low dissolved solids 

content (generally less than 350 mg/L). Lesney found 

that this water type was controlled by carbonate mineral equilibria and that the waters were undersaturated 

with respect to the minerals calcite and dolomite, 

owing to a lesser abundance of these minerals and 

shorter ground-water residence times in the upper 

basin than in the lower basin. In the lower Cuyahoga 

River Basin (which includes parts of Summit and Portage Counties), ground-water chemistry of the glacial 

deposits exhibited a wider range of water types and 

dissolved solids concentrations (143 to 2,077 mg/L). 

Waters in the lower basin generally were saturated or 

supersaturated with respect to calcite and dolomite. 

Lesney theorized that a combination of pyrite oxidation and gypsum dissolution, together with longer 

ground-water residence times in the lower basin, produced the calcium-magnesium sulfate waters found in 

the lower Cuyahoga River Basin. Sodium bicarbonatetype water found in the glacial deposits of the lower 

basin was attributed to discharge of sodium bicarbonate waters from the Cuyahoga Group, Berea Sandstone, and pre-Berea bedrock units along the margins 

of buried valleys. Sodium-chloride-type waters in the 

lower basin were thought to be caused by discharge of 

sodium chloride waters from Cuyahoga, Berea, and 

pre-Berea bedrock units and by infiltration of surface 

water that had been affected by runoff waters containing dissolved road salt.

Nichols (1980) sampled a total of 12 wells and 2 

springs in Geauga County. Four samples collected in 

May and 10 samples collected in October 1978 were 

analyzed for major ions and nutrients at all sites. Trace 

metals were determined in samples from four wells. 

2Maximum Contaminant Level (MCL) is the maximum permissible 

level of a contaminant in water delivered to any user of a public water 

system. MCLs are enforceable standards (U.S. Environmental Protection 

Agency, 2000).
14 Ground-Water Quality in Geauga County, Ohio

The purpose of the study was to assess water quality in 

the most developed aquifers in the county. These data 

could serve as a baseline to determine the effects of 

future ground-water development. Nichols found that, 

of the constituents analyzed for, only 5 of 14 iron samples and 6 of 14 manganese samples exceeded OEPA 

water-quality standards (Nichols,1980). Nitrate concentrations in 12 of 14 samples were less than 0.3 mg/L 

as N, within the range that Baker and others (1989) 

considered to represent natural, background levels. The 

other two samples had concentrations of 0.36 and 

2.4 mg/L. Elevated concentrations of barium and strontium (above background levels) were found in one well 

completed in the Berea Sandstone, which may indicate 

mixing with brines from deeper aquifers.

Eberts and others (1990) sampled 38 domestic 

and commercial wells in Geauga County in April and 

May 1986 to document background water quality in 

the glacial deposits, the Pottsville Formation, the 

Cuyahoga Group, and the Berea Sandstone. The samples were analyzed for fecal coliform and fecal streptococci bacteria; major ions; nutrients; the trace metals 

barium strontium and bromide; and phenols and methylene blue active substances (foaming agents). Like 

Nichols, Eberts found high iron and manganese concentrations to be widespread in the county. The 

USEPA Secondary Maximum Contaminant Level 

(SMCL)3 for iron of 300 μg/L (U.S. Environmental 

Protection Agency, 1988) was exceeded in 20 of 38 

samples. The SMCL for manganese of 50 μg/L (U.S. 

Environmental Protection Agency, 1988) was 

exceeded in 15 of 38 samples. The highest proportion 

of exceedances was in water from the glacial deposits, 

where 7 of 8 samples had iron and manganese concentrations exceeding the SMCL. 

Nitrate concentrations in 29 of 38 samples collected by Eberts and others (1990) were less than

0.3 mg/L as N, the concentration that Baker and others 

(1989) considered to represent natural, background 

levels. Of the 10 samples in which nitrate was 

detected, 9 were from the Pottsville Formation. The 

maximum concentration found was 6.0 mg/L as N, 

which is less than the USEPA MCL of 10 mg/L as N. 

Fecal coliform and (or) fecal streptococci bacteria 

were found in samples from 10 of the 38 wells tested, 

at concentrations ranging from less than 1 colony per 

100 milliliters (col/100 mL) to 6 col/100 mL. These 

bacteria were detected in all aquifers. Phenols and 

methylene blue active substances were present at very 

low concentrations (less than or equal to 4 μg/L and 

0.07 mg/L, respectively). Bromide/chloride mixing 

diagrams indicated that waters from at least 5 of the 38 

wells sampled were affected by road salt; all five of 

these wells were completed in the Pottsville Formation. Bromide/chloride data also indicated that waters 

from at least 1 of the 38 wells was affected by oilfield 

brine. 

Twelve of the wells that were sampled by Eberts 

and others (1990) had been sampled in 1978 (Nichols, 

1980) or in 1980 (unpublished data on file at the 

USGS office in Columbus, Ohio). Eberts and others 

(1990) graphically compared the water-quality data 

from two studies by plotting constituent concentrations as a function of time. No appreciable long-term 

temporal variations in ground-water quality had 

occurred between 1978 and 1986. 

Water-quality data for 62 wells in Chester 

Township were compiled by Jenkins (1987) from 

water-quality records from the Geauga County Board 

of Health, Ohio Environmental Protection Agency, the 

USGS, and a homeowner. The records examined 

reported a variety of analytes, but the major ions 

sodium, calcium, magnesium, chloride, bicarbonate, 

and sulfate were available in all the water-quality 

records. Jenkins noted anthropogenic effects on water 

quality, including high sodium and chloride concentrations in ground water at one location in southeastern 

Chester Township. Jenkins attributed the high concentrations to road deicing and (or) contamination from a 

salt-storage facility prior to 1981. 

Richards (1981) analyzed ground-water quality 

in October 1979 and May 1980, in the South Russell 

Village area of Russell Township. Richards collected 

21 surface-water samples and 29 ground-water samples from the glacial deposits, the Pottsville Formation, the Cuyahoga Group, and the Berea Sandstone. 

Samples were analyzed for water temperature, pH, 

specific conductance, alkalinity, chloride, nitrate, iron, 

sulfate, phosphate, silica, hardness, calcium, fluoride, 

sodium, and potassium. The pH of six samples from 

the Pottsville Formation was lower than 7.0 and, thus, 

outside the 7.0-10.5 range recommended by Ohio 

Environmental Protection Agency (1994). Acidic precipitation in the area combined with a short groundwater residence time was theorized as the origin of 

3

Secondary Maximum Contaminant Level (SMCL) is a nonenforceable, esthetically based standard set by the U.S. Environmental 

Protection Agency for public drinking water. SMCLs are established for 

constituents that can adversely affect the odor or appearance of water (U.S. 

Environmental Protection Agency, 2000).
Previous Studies 15

low-pH waters from shallow wells in recharge areas of 

the Pottsville Formation. Nitrates at concentrations 

greater than 0.3 mg/L were found in 12 ground-water 

samples (most of which were from the Pottsville Formation); however, none exceeded the MCL of 10 mg/L 

(U.S. Environmental Protection Agency, 2000). The 

SMCL of 300 μg/L for iron was exceeded in 14 of the 

29 ground-water samples. No samples exceeded the 

SMCL of 250 mg/L for chloride. When comparing the 

ground-water quality of the four major stratigraphic 

units in the study area to surface-water quality at base 

flow conditions, Richards (1981) stated that the quality 

of the water from the Pottsville Formation most 

closely resembled that of surface water at base-flow 

conditions.

Macdonald (1987) analyzed 37 ground-water 

samples from wells in and adjacent to Russell Township in September and October 1985. Samples were 

from the four major water-bearing units in the 

area—the glacial deposits, the Pottsville Formation, 

the Cuyahoga Group, and the Berea Sandstone. Samples were analyzed for major ions and nutrients. Two 

of the 37 samples had high sodium and chloride concentrations; the SMCL of 250 mg/L for chloride was 

exceeded in both samples. Macdonald attributed these 

elevated concentrations to brine contamination. Two 

other nearby wells contained water with dissolved-solids concentrations that exceeded the SMCL of 

500 mg/L. Macdonald also compared nitrate concentrations in wells from densely populated areas (greater 

than or equal to 10 houses clustered on lots of less than 

or equal to 1 acre) to those from sparsely populated 

areas (lots greater than or equal to 2 acres). Macdonald 

found that mean nitrate concentrations were statistically higher, at a 95-percent confidence level, in 

densely populated areas than in sparsely populated 

areas. All nitrate concentrations, however, were below 

the MCL of 10 mg/L as N. 

Grasso (1986) compared the results of Macdonald’s chemical analyses (1987) to those of Richards (1981) to determine whether water quality in the 

South Russell Village area was changing over time. A 

one-tailed t-test on the two groups of data indicated 

that the only ion concentration to increase significantly was phosphate; however, samples for the two 

studies were not collected from the same wells and 

were collected at different times of the year.

Water quality has been investigated in the 

county on a more site-specific scale by the Ohio Environmental Protection Agency (OEPA). Four principal 

sites of ground-water contamination in Geauga 

County have been confirmed by the OEPA. A fifth site 

was investigated for possible manganese contamination, but the manganese was determined to be naturally occurring.

Three of the contaminated sites are in Bainbridge Township. Two sites, in the northern part of 

Bainbridge Township near McFarland’s Corner (fig. 

1), were identified in December 1987. These two sites 

cover about 285 acres and are separated by a groundwater divide. Since 1987, five separate plumes of contamination have been identified at these two sites, 

affecting both the Sharon Member of the Pottsville 

Formation and the Berea Sandstone. Three of the 

plumes contain trichloroethylene, one contains 1,1,1-

trichloroethane (TCA) and tetrachloroethylene (also 

known as perchloroethylene, PCE), and one contains 

benzene and PCE contamination. Benzene concentrations were found at approximately 10 times the MCL, 

and PCE concentrations in one well were more than 

200 times the MCL. In 1996, a public water line that 

delivers water from Cuyahoga County was completed 

through the area; however, many of the public water 

supplies were not financially able to connect to the 

water line. A 1996 sampling effort also identified contamination in two residential wells and one publicsupply well to the east, beyond the public water line 

(Ohio Environmental Protection Agency, 1996a). 

At a third site in the northwestern corner of 

Bainbridge Township, OEPA collected 51 groundwater samples from public water supplies and residential wells. The analysis of these samples confirmed the 

presence of diethyl ether, dichloroethane (DCA), and 

other volatile organic compounds (VOCs) (Ohio Environmental Protection Agency, 1984). In 1993, water 

lines were installed in the community to provide potable water to residents (Ohio Environmental Protection 

Agency, 1996b). 

The fourth site of ground-water contamination 

is in Chester Township at the intersection of U.S. 

Highway 322 and State Route 306 (fig. 1). Ground 

water in this area has been affected by road-salt contamination (Ohio Environmental Protection Agency, 

1991). The road-salt storage piles that were determined to be the source of the contamination in the late 

1970s and early 1980s have since been underlain and 

covered. The ground water in the Sharon Member of 

the Pottsville Formation and the Berea Sandstone in 

the area also contains detectable concentrations of 

benzene, toluene, ethyl benzene, xylene, and other 
16 Ground-Water Quality in Geauga County, Ohio

chlorinated hydrocarbons. Leaking underground storage tanks at gas stations in the area and behind the 

police department building were removed or replaced 

with new tanks equipped with leak-detection systems, 

and monitoring wells were installed. No new wells 

may be drilled into the Sharon Sandstone in this area 

(Ohio Environmental Protection Agency, 1991), and 

investigation by OEPA is still ongoing.

A fifth site investigated by the OEPA for potential ground-water contamination was the Geauga 

Industries facility in Middlefield Township (Ohio 

Environmental Protection Agency, 1995). Groundwater samples were collected at three onsite production wells and 10 offsite residential wells and were 

analyzed for VOCs, semivolatile organic compounds 

(SVOCs), pesticides, polychlorinated biphenyls 

(PCBs), target analyte list metals, and strontium. In 10 

the residential samples, the only water-quality problem noted was that manganese and iron concentrations 

exceeded the SMCLs for these constituents (50 and 

300 μg/L, respectively) in 8 of the 10 samples. Manganese concentrations in several of the wells also 

exceeded the USEPA Removal Action Level (RAL)4

of 200 μg/L. The maximum manganese concentration 

in a residential well was 1,010 μg/L (Ohio Environmental Protection Agency,1995). 

A subsequent, expanded ground-water study 

(Bolas and Mohr, 1995) examined the occurrence of 

manganese in local ground water near the Geauga 

Industries site. Manganese concentrations in 28 residential wells west and south of the Village of Middlefield were determined. Most of the wells were 

completed in the Pottsville Formation. Manganese 

concentrations ranged from less than 10 μg/L to 

4,060 μg/L. Bolas and Mohr concluded that elevated 

concentrations of dissolved manganese occur naturally 

in local pockets within the region and are not confined 

to areas immediately adjacent to the Geauga Industries 

facility. Areas of elevated manganese in ground water 

may be related to variations in (1) the manganese content of bedrock, (2) the manganese content of glacial 

deposits, (3) the geochemical properties of ground 

water, such as Eh and pH, and (4) the number of ironand manganese-reducing bacteria in the subsurface.

METHODS OF STUDY

The current study expanded on the previous work by 

determining whether the undesirable concentrations of 

water-quality constituents and the anthropogenic 

effects on water quality that were reported by other 

researchers have become more widespread and (or) 

greater in magnitude. The undesirable concentrations 

reported consistently throughout the studies include 

those for manganese and iron in ground water that 

commonly exceed the SMCL. Road salt and, less commonly, oil-field brines have been found to affect 

ground water. VOCs have been found in ground water 

at isolated locations that were affected by leaking 

underground storage tanks containing gasoline or solvents. Nitrate has not been not a widespread waterquality problem, and it has not been detected above the 

MCL of 10 mg/L as N; however, nitrate has been 

found in some locations at levels that may indicate 

anthropogenic effects on the aquifers from fertilizer 

application or effluent from septic systems.

The current study added an additional time point 

(after a gap of 11years) to the temporal data reported 

by previous researchers. The most recent countywide 

water-quality sampling prior to this study that analyzed for a wide variety of water-quality constituents 

was that of Eberts and others (1990) in April and May 

1986. The oldest water-quality data for the area were 

collected by Nichols (1980) in 1978. These two studies provide a good baseline for comparison with the 

current study because (1) 12 of the wells sampled by 

Nichols and Eberts and others were common to both 

studies, (2) many of the properties and constituents 

analyzed for were the same, (3) both studies analyzed 

for a broad set of indicators for major water-quality 

issues, (4) the same laboratory (USGS National Water 

Quality Laboratory) was used in both studies, and 

most analytical methods were the same and, therefore, 

are comparable, (5) both studies sampled waters from 

the four major aquifers in the county and, (6) the spatial distribution of samples across the county was good 

in both studies. 

To examine current water-quality conditions and 

to determine changes in water quality since 1978 and 

1986, the USGS sampled 31 domestic and commercial 

wells from June 7 through July 1, 1999. Well locations 

are shown in figure 1, and well records are summarized in table 4. The following criteria were used in 

selecting these wells:

4

The RALs are drinking-water concentrations of compounds 

that are considered, along with other factors, in determining 

whether to provide alternate water supplies under Superfund 

removal authority. 
Methods of Study 17

• Resampling for Temporal Analysis - Efforts 

were made to resample wells used in previous 

USGS studies (Nichols, 1980; Eberts and others, 1990) so that temporal changes in water 

quality could be assessed. Unfortunately, none 

of the 12 wells that were sampled in both 1978 

and 1986 could be resampled because either (1) 

the well had been destroyed, (2) permission of 

the owner could not be obtained, or (3) the well 

was no longer in suitable condition for obtaining a representative water sample from the aquifer. Of the 26 additional wells that were sampled 

in 1986, 16 were resampled for the current 

study. Wells fitted with hand pumps were not 

resampled because of the difficulty of adequately sterilizing the drinking-fountain discharge fitting on the hand pump so that bacteria 

samples that were representative of the aquifer 

could be obtained. Wells sampled in both 1986 

and 1999 are shown in figure 4. 

• Spatial Distribution - Approximately two wells 

were selected in each township to provide even 

spatial distribution of data within the county.

• Stratigraphic Distribution - Wells completed in 

each of the primary stratigraphic units in the 

county were sampled in the quantities indicated: 

glacial deposits, 8 wells; Pottsville Formation, 

10 wells; Cuyahoga Group, 7 wells; and Berea 

Sandstone, 6 wells. Only wells completed in a 

single stratigraphic unit were used. 

• Flow-system Distribution - Wells from recharge 

zones, discharge zones, and intermediate positions within the flow system were sampled. 

Flowpath position was determined by use of 

potentiometric-surface maps (figs. 6 and 7) 

from Jagucki and Lesney (1995).

Samples were collected from household spigots 

using the existing plumbing fixtures and well pumps. 

Well owners identified spigots that provided untreated 

water. USGS personnel were able to inspect the 

plumbing at 16 of the 31 sites to verify untreated 

spigot designations. At only two of the sites (GE-85A 

and GE-234) was it possible to bypass the pressure 

tank for sampling. 

Upon arrival at a site, clean tubing was attached 

to the designated sampling spigot. The tubing contained three separate sampling ports—one made of 

Teflon for VOC sampling, one made of silicon for 

major-ion and trace-element sampling, and one that 

connected to a flowthrough chamber for measurement 

of pH, specific conductance, temperature, and dissolved oxygen. The flowthrough chamber did not 

allow contact of the water with air prior to measurement. Even though all wells sampled were in regular 

use, water was pumped from the well before sampling 

to eliminate stagnant water that had been standing in 

the well bore, pressure tank, and pipes and to ensure 

that subsequent samples reflected the chemistry of 

water in the aquifer. Purging also helped to condition 

the sampling equipment and reduce turbidity caused 

by startup of the pump (Koterba and others, 1995). 

Purge volume was calculated as:

,

 

where 

Vp is purge volume, in cubic feet;

Vt is pressure-tank volume, in cubic feet;

r is inside radius of the well casing, in feet;

WellDepth is depth of well from top of casing, in 

feet; and

StaticLevel is distance from the top of casing to 

the static water level, in feet.

A volume of water equal to 1.6 to 4.3 purge volumes 

was removed from each well prior to sampling. Sampling did not begin until successive measurements of 

pH, specific conductance, dissolved oxygen, and temperature had stabilized. 

Before sampling, flow rate through the sampling 

tube was reduced to 0.1 gal/min, leaving discharge 

through other tubes at the purge rate. The water was 

allowed to discharge at the purge rate in an attempt to 

keep the pump from cycling off after the pressure tank 

was filled. This procedure also reduced the likelihood 

of backflow of water stored in adjacent plumbing 

lines. 

VOC samples were collected in 40-mL vials by 

means of Teflon fill tubes; no headspace was allowed 

in the bottle (Koterba and others, 1995). Attempts 

were made to ensure that samples were not collected 

downwind of car exhaust or other VOC sources. At the 

one location with a noticeable hydrocarbon odor, an 

ambient VOC blank sample was collected. Sulfide was 

determined in the field on an unfiltered sample with a 

spectrophotometer, by use of the methylene blue 

method (Hach Company, 1989). Dissolved organic 

carbon (DOC) samples were filtered through a 

0.45-μm silver filter. Other major-ion and trace-element samples were filtered through a 0.45-μm inline

Vp Vt π r

2 = + [ ] ( ) × ( ) WellDepth StaticLevel –
18 Ground-Water Quality in Geauga County, Ohio

Table 4. Physical characteristics of wells sampled in Geauga County, Ohio, June and July 1999

[LS, land surface; MP, measuring point.]

Well name Site identifier Latitude Longitude Township

Land 

surface 

datum 

(feet)

MP 

height

(feet 

above 

LS)

Aquifer

Open interval

(feet below LS)

Top Bottom

GE-23 412309081202400 41°23’09” 81°20’24” Bainbridge 1,162 1.32 Pottsville 31 40

GE-77 413028081221000 41°30’28” 81°22’10” Chester 1,140 2.07 Cuyahoga 80 155

GE-85Aa 412716081125401 41°27’16” 81°12’54” Newbury 1,220 2.23 Pottsville 72 140

GE-101 413757081122300 41°37’57” 81°12’23” Chardon 990 .90 Glacial 48 48

GE-103 413755081101200 41°37’55” 81°10’12” Hambden 1,158 .40 Berea 133 136

GE-104 413606081102100 41°36’06” 81°10’21” Hambden 1,215 1.25 Berea 187 204

GE-108 413117081171900 41°31’06” 81°17’19” Munson 1,120 .60 Glacial 132 132

GE-109 413005081130000 41°30’02” 81°13’02” Munson 1,280 1.50 Pottsville 89 105

GE-119 412657081040500 41°26’58” 81°04’12” Middlefield 1,185 1.50 Pottsville 21 79

GE-120 413230081190200 41°32’30” 81°19’02” Chester 1,115 1.00 Berea 91 135

GE-122 412410081223900 41°24’10” 81°22’39” Bainbridge 1,010 1.20 Berea 94 135

GE-126 412212081230100 41°22’12” 81°02’53” Parkman 1,070 1.50 Berea 136 200

GE-141 412224081084300 41°22’24” 81°08’43” Troy 1,118 .80 Glacial 53 53

GE-147 412845081030100 41°28’45” 81°03’01” Middlefield 1,120 1.90 Cuyahoga 54 63

GE-151 412319081135000 41°23’19” 81°13’50” Auburn 1,270 2.30 Pottsville 64.5 148

GE-157 413628081060500 41°36’28” 81°06’05” Hambden 1,185 1.50 Glacial 36 36

GE-159 412442081102100 41°24’20” 81°10’21” Troy 1,140 1.40 Berea 237 286

GE-165 412319081163000 41°23’19” 81°16’30” Auburn 1,165 1.20 Glacial 56 56

GE-174Ab 412907081202101 41°29’07” 81°20’21” Russell 1,060 1.15 Glacial 85c 85d

GE-185A 413630081145001 41°36’30” 81°14’50” Chardon 1,260 .84 Cuyahoga 68.5 90

GE-202 413607081032500 41°36’07” 81°03’25” Montville 1,247 1.60 Pottsville 51 74

GE-204 413256081045800 41°32’56” 81°04’58” Huntsburg 1,230 .70 Pottsville 46 53

GE-228 412408081221500 41°24’08” 81°22’15” Bainbridge 1,060 1.00 Cuyahoga 37 65

GE-234 412948081090000 41°29’48” 81°09’00” Burton 1,170 1.33 Cuyahoga 40 80

GE-235 412733081094600 41°27’33” 81°09’46” Burton 1,105 1.81 Glacial 46 51e

GE-280 413127081025900 41°31’27” 81°02’59” Huntsburg 1,145 1.45 Cuyahoga 62 162

GE-321 412318081003200 41°23’18” 81°00’32” Parkman 925 2.25 Glacial 89 92f

GE-332 412558081184200 41°25’58” 81°18’42” Russell 1,180 1.14 Pottsville 48 104

GE-341 414121081030800 41°41’21” 81°03’08” Thompson 1,267 2.00 Cuyahoga 72 120

GE-349A 413247081103301 41°32’47” 81°10’33” Claridon 1,190 1.32 Pottsville 16.5g 49.5

GE-355 413910081043900 41°39’10” 81°04’39” Thompson 1,222 .60 Pottsville 63 71

a

Well GE-85A is near the former location of and is completed at a depth very similar to that of well GE-85, which was sampled in 1978. b

Well GE-174A was redrilled 20 feet from the location of well GE-174, which was sampled in 1986. The new well is completed about 20 

feet shallower in the same formation.

c

 Estimated value based on the observation that other wells in the area that are completed in glacial deposits are constructed as open-ended 

wells.

d

 Value reported by owner.

e

 Slotted polyvinylchloride (PVC) well screen, 30 slot.

f

 Stainless steel well screen, 10 slot.

g

 Estimated value based on construction of adjacent well and the observation that other Pottsville wells in the area are cased through the 

glacial deposits and have an open hole through the Pottsville Formation.
Ground-Water Quality 19

nylon capsule filter. Trace-element samples were acidified to pH less than 2.0 by use of nitric acid to ensure 

that trace elements did not precipitate (Koterba and 

others, 1995). Alkalinity was determined in the field 

by means of the incremental titration method (Wilde 

and Radtke, 1998). Tritium samples and some majorion samples were unfiltered. No headspace was 

allowed in the tritium samples. Tritium samples were 

collected at each of the 31 wells, and 14 were later 

selected for analysis on the basis of the following criteria:

 • representation of ground water from recharge, 

discharge, and mid-flowpath positions, as determined from potentiometric-surface maps (figs. 6 

and 7) by Jagucki and Lesney (1995),

• spatial distribution of wells completed at various 

depths,

• representation of ground water from wells completed in the same formation but at locations 

having various degrees of stratigraphic confinement,

• unexpected presence of total coliform bacteria 

and,

• location of the well along a simulated groundwater flowpath for which residence times were 

estimated by Eberts and others (1990). The calculated residence time could later be compared 

to the tritium-analysis results.

Water samples to be analyzed for total coliform 

and Escherichia coli (E. coli) were collected after the 

spigot had been wiped with ethanol, the ethanol had 

evaporated, and the spigot had been rinsed with sterile 

water. Bacteria samples were plated in the field, within 

30 minutes of collection, using the membrane filtration method with MI agar (Brenner and others, 1993). 

Samples were incubated at 35°

C for 24 hours, after 

which all blue colonies were counted as E. coli and all 

colonies that fluoresced under a blacklight were 

counted as total coliforms (Brenner and others, 1993).

All VOC, DOC, and nutrient samples were 

chilled to 4°

C and were shipped overnight to the analyzing laboratory. A VOC screen was done at the 

USGS office in Columbus, Ohio, by means of a portable gas chromatograph with a heated column and a 

calibration library consisting of benzene at 3 μg/L, 

trichloroethylene at 5 μg/L, toluene at 3 μg/L, tetrachloroethylene at 5 μg/L, and xylene at 13 μg/L. 

Nutrients were determined by a water-quality laboratory at Heidelberg College in Tiffin, Ohio. All other 

properties and constituents were determined by the 

USGS National Water Quality Laboratory in Denver, 

Colo. 

The sampling equipment was cleaned between 

sites to eliminate cross-contamination of samples 

(Koterba and others, 1995). The sample tubing, filters, 

and glassware were disassembled and allowed to soak 

for at least 10 minutes in clean, colorless basins filled 

with a 0.1 percent solution by volume of nonphosphate 

detergent in deionized water. Parts were then scrubbed 

with a brush and rinsed three times with deionized 

water to remove detergent and particulates. The equipment used for VOC sampling was then rinsed three 

times with small amounts of methanol and allowed to 

air dry. When the VOC equipment was dry, it was 

wrapped with foil. 

Bacteria-sampling equipment was rinsed three 

times with tap water and three times with deionized 

water and then was sterilized by soaking in a 1/250 

dilution of household bleach and tap water for 30 minutes. The equipment was then dechlorinated by soaking in a sterile sodium thiosulfate solution for 5 

minutes. After dechlorination, all parts were rinsed at 

least three times with sterile water. Open ends of tubing and equipment were covered with foil after sterilization.

Quality-assurance/quality-control samples, 

including field blanks, duplicate samples, and sourcesolution blanks, were collected for most analytes at the 

rate of 10 percent to ensure sample integrity and final 

quality of data. More stringent quality-assurance/quality-control procedures were applied to bacteria and 

VOCs. Types of quality-control samples and the 

method and frequency of collection are discussed in 

more detail in Appendix A. 

GROUND-WATER QUALITY

Water-quality data were used to determine (1) suitability of water for drinking, (2) age of ground water, (3) 

stratigraphic variation in water quality, (4) controls on 

water quality, and (5) temporal variation in water quality. 

Results of analyses of water-quality samples 

collected in Geauga County in 1999 are listed in table 

5 (at back of report). A reference of regulatory drinking-water standards for each of the properties and constituents analyzed for in this study, along with possible 

sources and effects on ground water, is provided in 

table 6 (at back of report). 
20 Ground-Water Quality in Geauga County, Ohio

An examination of table 5 makes evident that 

samples from wells GE-119 and GE-159 contain 

unusually high concentrations of sodium and unusually low concentrations of calcium and magnesium 

when compared to other samples. GE-119 and GE-159 

also have unusually low concentrations of hardness, 

iron, manganese, and strontium. This pattern indicates 

that these water samples were softened by ionexchange methods (Driscoll, 1986). Followup investigation revealed that water from well GE-119 was 

softened by a water-treatment system at the point sampled; however, no water-treatment devices were used 

on well GE-159; water in this well is softened by natural geochemical processes and has major ions in proportions that are comparable to those of certain water 

samples from the Berea Sandstone documented by 

Lesney (1992) and Richards (1981). Because of the 

water-treatment system installed on well GE-119, data 

from this well are omitted from subsequent discussions of sodium, hardness, calcium, magnesium, manganese, iron, and strontium.

Suitability of Water for Drinking

Because no regulatory standards apply to the 

chemical quality of domestic wells in Ohio, constituent concentrations documented during this study are 

compared to OEPA standards (Ohio Environmental 

Protection Agency, 1994) that are enforceable only for 

public water supplies that serve 25 or more people. 

The Geauga County General Health District’s standard 

for total coliform bacteria in raw water from newly 

constructed wells also was used to assess suitability 

for drinking.

Bacteria. OEPA regulatory standards for total 

coliform bacteria, as listed in table 6, are established 

for public-supply wells that are sampled several times 

a month. Because samples for the current study were 

collected at only one time point, it is difficult to compare results to the OEPA drinking-water standards. 

The Geauga County General Health District standard 

for a newly constructed well is 0 total coliform colonies per 100 mL of water (Bob Wiesdak, Geauga 

County General Health District, oral commun., 1999). 

This standard is applicable to domestic wells. Using 

the criteria of the Geauga County General Health District, water from 16 of the 31 wells exceeded the 

health-based standard for total coliform. Coliform bacteria are indicator organisms. Some coliform bacteria 

can occur naturally in the soil, whereas others have a 

source related to the intestines of humans and other 

warmblooded animals. The presence of coliform bacteria indicates a possibility, but not a certainty, that disease-causing organisms also may be present in the 

water because of contamination from human or other 

animal wastes. To confirm contamination by a fecal 

source, the water was analyzed for Escherichia coli

(E. coli), a species in the total coliform group that 

originates in the intestines of humans and other warmblooded animals. E. coli were not detected in any of 

the wells sampled. Although the presence of E. coli

would have confirmed contamination by a fecal 

source, the absence of E. coli does not rule out fecal 

waste as one possible source of the total coliform bacteria. The Geauga County General Health District recommends that private wells in which total coliforms or 

E. coli are detected should be disinfected, because a 

properly constructed well should not contain coliform 

bacteria. 

Volatile Organic Compounds. The USGS 

analytical screening for VOCs detected no benzene, 

toluene, xylene, trichloroethylene, or tetrachloroethylene (also known as perchloroethylene) compounds at 

the detection limits defined in table 5, which are at or 

below the MCLs for these compounds. This absence 

of detections indicates that VOC contamination is not 

a widespread problem in the county; however, VOCs 

have rendered water unsuitable for drinking at specific 

locations identified in the “Previous Studies” section 

of this report (Ohio Environmental Protection Agency, 

1984, 1991, 1996a, and 1996b). It should be noted that 

USGS personnel were able to bypass the pressure tank 

at only two of the sites sampled. VOCs would tend to 

volatilize from the water upon pressurization within 

the tank, so the results of the USGS analyses for VOCs 

may be erroneously low.

Nitrate and Nitrite. No samples in either the 

current study or in any of the investigations described 

in the “Previous Studies” section of this report 

exceeded the health-based standard for nitrate (MCL 

of 10 mg/L as N) in drinking water. The health-based 

MCL for nitrite (1 mg/L as N) also was not exceeded 

in the current study. (Nitrite concentrations were not 

determined separately from nitrate concentrations in 

the previous studies.) 

Esthetic Considerations. Although the 

SMCL of 250 mg/L for chloride was not exceeded, 

esthetically based SMCLs were exceeded in the indicated number of wells for pH (8), sulfate (1), dissolved 

solids (3), iron (19), and manganese (18). Possible 

implications of not meeting each of these the SMCLs 
Age of Ground Water 21

are listed in table 6. Bolas and Mohr (1995) investigated complaints of high manganese concentrations in 

ground water of southeastern Geauga County, comparing manganese concentrations in 18 raw and treated 

water samples from domestic wells. They determined 

that, although manganese concentrations that exceed 

the SMCL (50 μg/L) are common in Geauga County, 

most properly operating residential water-treatment 

systems were effective at reducing elevated manganese concentrations to below the esthetically based 

drinking-water standard. 

Although there is no drinking-water standard for 

hydrogen sulfide (H2S), its characteristic rotten-egg 

odor can make drinking water unpalatable. Hydrogen 

sulfide was detected in 17 of the 31 wells sampled at a 

detection limit of less than 0.01 mg/L, but it was listed 

as a chronic odor complaint by only 8 well owners. 

Hydrogen sulfide concentrations in water can be 

reduced by use of in-home ozonation systems (Melligan, 2000) or catalytic carbon filters (Brooks, 1998). 

Hardness is a term associated with the interaction of water and soap and (or) the encrustations left 

when water is heated. Because the presence of calcium 

and magnesium causes most of the observed soap 

effects, hardness is computed from calcium and magnesium concentrations reported as an equivalent concentration of calcium carbonate (Hem, 1989, p. 158-

159). The greater the hardness of the water, the more 

soap is consumed and the more mineral encrustation is 

left behind after heating. According to the hardness 

classification used for this study (table 6), 25 of the 31 

samples were hard to very hard water. Only five samples were soft to moderately hard water. (The remaining sample, from well GE-119, was found to be 

artificially softened.)

Age of Ground Water

The age of ground water has implications for 

management of water resources. In terms of water supply, ground water that receives some component of 

modern recharge is being continuously renewed, and 

its use is potentially sustainable (Clark and Fritz, 

1997). In terms of water quality, age of ground water 

is an indicator of susceptibility of an aquifer to human 

activities at or near land surface. Ground water that 

recharged the aquifer after about 1950 is more susceptible to near-surface contamination than older waters 

because “relatively little time has passed to allow for 

attenuation of contaminants in the subsurface, and 

because regulated chemicals have been introduced into 

the environment in large quantities since the mid 

1940’s, following World War II” (Harlow and others, 

1999). 

Dating of 14 ground-water samples from 

Geauga County was done by use of tritium analyses 

(Michel, 1989; Clark and Fritz, 1999). Tritium, whose 

chemical symbol is 3

H, is a radioactive isotope of 

hydrogen that is naturally produced in the Earth’s 

atmosphere at low concentrations; however, large 

quantities of manmade tritium were released to the 

atmosphere from the early 1950s to the mid-1960s by 

the testing of nuclear weapons. Tritium concentrations 

increased two to three orders of magnitude with the 

onset of testing, peaking in 1963 (Michel, 1989). Tritium concentrations in precipitation began declining 

with the cessation of Soviet and American nuclear 

atmospheric testing in the mid-1960s. Concentrations 

of tritium in precipitation during calendar year 2000 at 

stations in Penola, Ga., and Shenandoah National 

Park, Va., ranged from 2.7 to 4.3 TU (Robert L. 

Michel, U.S. Geological Survey, written commun., 

2001).

Other than radioactive decay, tritium is not significantly affected by geochemical reactions, so it is 

thus useful for dating ground water. Estimates of tritium concentration in precipitation that fell in northern 

Ohio from 1953 to 1983 (and subsequently entered the 

ground-water system) were made by Michel (1989). 

Given a half-life of tritium of 12.43 years (International Atomic Energy Agency, 1981), these estimated 

input concentrations were corrected for radioactive 

decay up to the time of ground-water sample collection (June and July 1999) and are shown in figure 8. 

For example, for a well yielding water recharged in 

1963 that has not been mixed with waters recharged in 

other years, the tritium concentration would be 390 tritium units (TU) in a sample collected in 1999. Similarly, radioactive decay has reduced the tritium in 

waters recharged prior to 1953 to concentrations that 

are less than 1.8 TU in 1999.

In reality, a sample of ground water is most 

likely a mixture of several years of precipitation. Thus, 

only a qualitative interpretation of ground-water ages 

can be made. Ground-water samples with tritium concentrations less than the detection limit of 1.8 TU are 

considered to have reached the water table as recharge 

prior to 1953 or are mixtures of pre-1953 waters and 

recent recharge with a low tritium concentration. Such 

waters are referred to in subsequent paragraphs as 

“predominantly old waters.” Waters with tritium con-
22 Ground-Water Quality in Geauga County, Ohio

1950 1955 1960 1965 1970 1975 1980 1985

0

400

50

100

150

200

250

300

350

TRITIUM CONCENTRATION,

Figure 8. Estimated annual mean tritium concentration, corrected for radioactive decay through 

1999, in precipitation that fell in northeastern Ohio, 1953 to 1983. (Tritium concentrations in original 

precipitation based on tritium deposition estimates by Michel, 1989.)

 IN TRITIUM UNITS

centrations greater than 1.8 TU are considered to have 

been recharged after 1953 or consist of a mix of waters 

containing a component of post-1953 recharge. These 

waters will be hereafter referred to as “predominantly 

young waters.” The age determination of water with a 

tritium concentration of greater than 60 TU could be 

further narrowed to indicate that the water originated 

as recharge between 1962 to 1966 (fig. 8). 

Results of tritium analyses are given in table 5 

and are plotted as a function of depth in figure 9. Most 

waters are predominantly young. Because all young 

waters contained tritium at concentrations greater than 

1.8 TU and less than 60 TU, age of these waters could 

not be refined beyond a qualitative post-1953 recharge 

date.

Only three wells (GE-108, GE-120, and GE202) yielded predominantly old waters. This category 

included the only sample from the Berea Sandstone 

(GE-120) that was dated. In the vicinity of GE-120, 

the Berea is overlain by 78 ft of glacial deposits and 

13 ft of Cuyahoga Group. The sample from GE-202 

was the only water collected from a location where the 

shale unit of the Sharon Member is present as the 

uppermost unit of the Pottsville Formation. Although 
Age of Ground Water 23

0 2 4 6 8 10 12 14 16 18 20 22 24 26

TRITIUM CONCENTRATION,

0

180

20

40

60

80

100

120

140

160

TOTAL DEPTH OF WELL,

Glacial deposits

Pottsville Formation

Cuyahoga Group

Berea Sandstone

GE-108

GE-120

GE-202

GE-228

GE-185A

Young waters

Old

waters

Detection limit = 1.8 

Figure 9. Tritium concentrations in ground water and well depth in Geauga County, Ohio, 

June and July 1999. (Definitions of old and young waters are given on p. 21) IN FEET BELOW LAND SURFACE

 IN TRITIUM UNITS

Pottsville waters were predominantly old at GE-202, 

samples that were collected from other locations 

where the Pottsville Formation is not capped by the 

shale unit were predominantly young—even where the 

total depth of the well was greater than that of GE-202 

(fig. 9). 

The glacial waters that were tested for tritium 

also were predominantly young, with the exception of 

the sample from well GE-108. The predominantly old 

age for this well water is problematic. Well GE-108 is 

relatively deep (132 ft), and the open interval is overlain by 83 ft of clay. Yet, chloride and dissolved solids 

concentrations in water from this well are low compared to those at other wells (table 5), indicating a 

short residence time rather than the long one that is 

indicated by the low tritium concentration. The presence of bacteria in GE-108 also indicates a mixing 

with recent recharge. One factor contributing to the 

low tritium concentration in this well may be its location in a buried valley. The valley formed by erosion 

through the Pottsville Formation, Cuyahoga Group, 

Berea Sandstone, and into the pre-Berea bedrock 

units, and the valley has since been filled with glacial 

deposits. Eberts and others (1990) and Jagucki and 

Lesney (1995) determined that waters from the bedrock units discharge into this buried valley. Mixing of 

young water originating in the glacial deposits with 

old, deep bedrock water might dilute the tritium concentration at GE-108 to less than 1.8 TU, especially if 

the water originating from the glacial deposits is very 

recent (post-1987) recharge with a low tritium concentration. 

Two samples of water from the Cuyahoga Group 

were chosen for analysis. One sample (GE-185A) is 
24 Ground-Water Quality in Geauga County, Ohio

from a location where the shale is overlain by 35 ft of 

Pottsville Formation, and recharge to the Cuyahoga 

Group occurs as precipitation seeping through this 

overlying bedrock. The second sample (GE-228) was 

collected from an area where the Cuyahoga Group is 

the uppermost bedrock unit and is overlain by only 9 ft 

of clay. Waters from both wells, GE-185A and 

GE-228, were classified as predominantly young.

The tritium data agree with the residence times 

estimated by Eberts and others (1990) by use of a 

three-dimensional, steady-state flow model in conjunction with a particle-tracking program. The residence time associated with each simulated flowpath 

indicates the number of years it would take for a particle of water to travel the entire length of the groundwater flowpath, beginning when the water particle 

reaches the water table and ending when the water particle discharges to a stream. Approximate residence 

times estimated by Eberts and others for simulated 

flowpaths in the Pottsville Formation and (or) the glacial deposits ranged from 15 to 170 years. Residence 

times for flowpaths in the Berea Sandstone ranged 

from 70 to 4,800 years.

Among the sites for which samples were dated, 

three of the wells completed in the Pottsville Formation (GE-85A, GE-109, and GE-349A) lie roughly 

along three separate ground-water flowpaths simulated 

by Eberts and others (1990). Eberts and others determined ground-water residence times for the three relevant flowpaths to be 50, 40, and 15 years, respectively. 

Because wells GE-85A, GE-109, and GE-349A intercept the simulated flowpaths about three-quarters to 

one-half of the way along the length of the simulated 

flowpath, one would expect to find water ages that are 

three-quarters to one-half of the computed residence 

times (that is, no more than 37.5 years). One would 

expect waters of this age to be tritiated and classified 

as predominantly young waters. Tritium dating does, 

in fact, show the waters from these wells to be predominantly young.

The dating results signify that waters of the glacial deposits, Pottsville Formation, and Cuyahoga 

Group are all part of the active hydrologic cycle. Thus, 

as stated previously, waters withdrawn from these 

stratigraphic units for water supply can be replenished 

(at least in part), but their quality may be susceptible to 

influence of human activity.

Stratigraphic Variation in Water Quality

Stratigraphic variation in chemical composition 

of ground water can be examined by use of a trilinear 

diagram (fig. 10). This type of trilinear diagram is constructed by converting concentrations of anions and 

cations to milliequilavents per liter (meq/L) and plotting relative percentages of the major cations on the 

lower left equilateral triangle and the major anions on 

the lower right equilateral triangle (Hem, 1989). Each 

corner on the triangles represents 100 percent of a particular type (or types) of ions. The cation and anion 

compositions are then projected along a line parallel to 

the outer edge of the equilateral triangles until the cation and anion projections intersect on a third, diamond-shaped diagram. Plotting of the data in this way 

makes evident some characteristics of the waters and 

some constraints that must be considered in interpreting the geochemical evolution of the waters. 

Several characteristics need to be considered 

when interpreting figure 10:

 1. The data do not plot as distinct groupings by 

stratigraphic unit. In fact, a range of water 

types can occur within a single unit. 

2. The data can be divided into three groups on 

the basis of predominant anion type:

a. Most waters, regardless of aquifer, are 

dominated by the bicarbonate anion. 

These bicarbonate-type waters have quite 

a range of cation types, from calciumdominated waters (predominantly from 

the glacial deposits and Pottsville Formation) to mixed calcium-magnesiumsodium waters (including waters from 

every unit except the Pottsville Formation), to sodium-dominated waters. The 

sodium bicarbonate waters were found at 

two locations—wells GE-321 (glacial) 

and GE-159 (Berea). 

b. The second group of waters are those that 

would be considered chloride-type waters 

or waters of mixed anion type (mixtures of 

chloride, bicarbonate, and sulfate). For the 

purposes of this report, both types of water 

will be referred to as chloride-type waters. 

The four samples in this category (GE-23, 

228, 341, and 349A) have at least 45 relative percent chloride, and all are from the 

Pottsville Formation or the Cuyahoga 

Group. Cation types in this group are a 

mixture of calcium, magnesium, and 
Stratigraphic Variation in Water Quality 25
26 Ground-Water Quality in Geauga County, Ohio

sodium, except for GE-341, which is dominated by sodium. 

c. The third type of water is dominated by 

the sulfate anion. The only sample in this 

category is GE-122 from the Berea Sandstone, which has approximately 60 relative percent sulfate and would be 

classified as a calcium-magnesium-sulfate-type water. 

The significance of the three types of waters will be 

discussed in “Controls on Water Quality.”

Another visual method for examining differences in water chemistry between the four main stratigraphic units is the use of boxplots (fig. 11). The 

boxplots allow visual comparison of median concentration, interquartile range (the distribution of the data 

that lie between the 75th percentile and the 25th percentile), and total range of measured values. Statistical 

tests (a nonparametric Kruskall-Wallis analysis of 

variance followed by Tukey’s t-test) also were done on 

each constituent grouped by stratigraphic unit, to 

determine whether differences were statistically significant at the 95-percent confidence interval (SAS 

Institute, 1990). Boxplots showing no statistically significant difference between units are indicated by a 

common letter (such as “A”) in figure 11. Boxplots 

showing a statistically significant difference between 

units are indicated by a different letter and are referred 

to as having “significantly different” concentrations in 

subsequent discussions. 

As with the trilinear diagram, the boxplots indicate more similarities than differences between the 

chemistry of the four stratigraphic units. No statistically significant differences in constituent concentrations between units were found for calcium, 

magnesium, sulfide, sulfate, chloride, bromide, silica, 

and manganese. Neither are there significant differences in specific conductance or concentrations of dissolved oxygen, total coliform, hardness, dissolved 

solids, or organic carbon. The absence of statistical 

difference is due in part to a large interquartile range 

as is evident on some of the boxplots. A large interquartile range represents variability in constituent concentration between sampling locations within a 

stratigraphic unit. Variability of constituent concentrations in the Cuyahoga and Berea waters likely is 

caused by the varying degrees of stratigraphic confinement of these units. For instance, in some places the 

full stratigraphic column as shown in table 3 is 

present, and recharging water must filter through all of 

these units before making its way to the lower bedrock 

aquifers. In other locations, the upper bedrock units 

have been removed by erosion (fig. 5), and recharge 

waters flow only through the glacial deposits before 

reaching the Cuyahoga Group or the Berea Sandstone. 

In all stratigraphic units, the Geauga County 

General Health District standard for total coliform in 

domestic wells was exceeded in at least one location, 

as well as the SMCLs for iron and manganese. Notable 

chemical characteristics shown by the boxplots are 

discussed below for each unit.

Glacial Deposits. Waters of the glacial 

deposits generally are anoxic; dissolved oxygen concentrations were at or below the detection limit of 

0.1 mg/L in seven of the eight samples collected from 

wells completed in the glacial deposits. Even though 

the glacial deposits are the uppermost stratigraphic 

unit in the area and thus might be expected to be oxygenated, well construction in this unit is such that 

water enters the well only at the bottom of the well. 

Well screens are not typically used in glacial wells in 

the area; and because the glacial sediments are unconsolidated, an unscreened hole does not remain open. 

Therefore, the depth to the top of the open interval for 

glacial wells, as shown in figure 12, is equal to the 

total depth of the well (table 4). 

Total coliform concentrations are highly variable in the glacial deposits, and include the highest 

concentration found (120 col/100 mL), as well as the 

greatest median concentration (6 col/100 mL). 

Another unusually high constituent concentration, 

noted as an outlier on the boxplot, is a sodium concentration of 120 mg/L from well GE-321. Chloride concentrations at this well are discussed later in the 

“Anthropogenic Effects” section of this report. Iron 

concentrations in six out of eight glacial water samples 

exceed the SMCL. 

Pottsville Formation. Waters from the Pottsville Formation are unique in various ways. First, dissolved oxygen, nitrate, and total coliform 

concentrations in the Pottsville Formation exhibit a 

wide range of values and elevated concentrations relative to the other stratigraphic units, although differences are not always statistically significant. The 

Pottsville Formation has the highest median concentration of dissolved oxygen (0.8 mg/L) and nitrate (0.3 

mg/L as N) among the four stratigraphic units. Of the 

six locations at which nitrate was detected in this 

study, five were in the Pottsville Formation. Part of the 

reason for elevated dissolved oxygen and nitrate con-
Stratigraphic Variation in Water Quality 27

(8) (7) (10)

(6)

10

4

5

6

7

8

9

GLACIAL

POTTSVILLE

CUYAHOGA

BEREA

(8)

(7)

(10)

(5)

0

10

2

4

6

8

DISSOLVED OXYGEN CONCENTRATION,

pH, IN STANDARD UNITS

Figure 11. Boxplots of chemical constituents delineated by stratigraphic unit for the 1999 sampling in 

Geauga County, Ohio. (Sample GE-119 not included in boxplots where constituent concentrations 

are affected by artificial water-softening system. Results of Tukey’s t-test are represented as letters, 

and concentrations with at least one letter in common do not differ significantly at the 95-percent IN MILLIGRAMS PER LITER

A A A A

A B BC AC

GLACIAL

POTTSVILLE

CUYAHOGA

BEREA

(8)

(7)

(10)

(6)

200

1,600

400

600

800

1,000

1,200

1,400

SPECIFIC CONDUCTANCE,

 IN MICROSIEMENS PER CENTIMETER

(8)

(7)

(10)

(6)

10

14

11

12

13

(8)

WATER TEMPERATURE, IN DEGREES CELSIUS

A A A A

A A A A

Lower SMCL = 7.0

EXPLANATION

25th percentile

Median

75th percentile

interquartile range outside the quartile

Data value less than or equal to 1.5 times the

interquartile range outside the quartile

and more than 1.5 times the

Outlier data value less than or equal to 3

interquartile range outside the quartile

Outlier data value more than 3 times the

(8) Number of observations

A Grouping from Tukeys t-test

SMCL = Secondary Maximum Contaminant Level

Detection limit of machine measuring parameter

SMCL = 250 milligrams per liter

Detection limit = 0.18 milligrams per liter
28 Ground-Water Quality in Geauga County, Ohio

(8)

(7)

(10)

(6)

0

7

2

4

6

POTASSIUM CONCENTRATION,

 IN MILLIGRAMS PER LITER

ABD B C CD

GLACIAL

POTTSVILLE

CUYAHOGA

BEREA

GLACIAL

POTTSVILLE

CUYAHOGA

BEREA

(8)

(7)

(9)

(6)

0

200

50

100

150

CALCIUM CONCENTRATION,

 IN MILLIGRAMS PER LITER

A A A A

(8)

(9) (7)

0

80

20

40

60

MAGNESIUM CONCENTRATION,

(6)

 IN MILLLIGRAMS PER LITER

A A A A

SODIUM CONCENTRATION,

 IN MILLIGRAMS PER LITER

(8)

(7)

(9)

(6)

0

200

50

100

150

AB A AB B

Figure 11. Boxplots of chemical constituents delineated by stratigraphic unit for the 1999 sampling in 

Geauga County, Ohio —Continued.

(7)

(10)

(6)

0

120

20

40

60

80

100

(8) (7)

(9)

(6)

0

800

200

400

600

TOTAL COLIFORM CONCENTRATION,

HARDNESS CONCENTRATION,

(8)

 IN COLONIES PER 100 MILLILITERS

 IN MILLIGRAMS PER LITER

A A A A A A A A
Stratigraphic Variation in Water Quality 29

(8)

(7)

(10)

(6)

0

0.4

0.1

0.2

0.3

BROMIDE CONCENTRATION,

 IN MILLIGRAMS PER LITER

GLACIAL

POTTSVILLE

CUYAHOGA

BEREA

GLACIAL

POTTSVILLE

CUYAHOGA

BEREA

A A A A

(8)

(7)

(10)

(6)

0

1.4

0.2

0.4

0.6

0.8

1.0

1.2

1.4

SULFIDE CONCENTRATION,

 IN MILLIGRAMS PER LITER

A A A A

(8) (7)

(10)

(6)

0

600

100

200

300

400

500

SULFATE CONCENTRATION,

(8)

 IN MILLIGRAMS PER LITER

A A A A

(8)

(7)

(6)

0

250

50

100

150

200

CHLORIDE CONCENTRATION,

(10)

 IN MILLIGRAMS PER LITER

A A A A

SMCL = 250 milligrams per liter

Figure 11. Boxplots of chemical constituents delineated by stratigraphic unit for the 1999 sampling in 

Geauga County, Ohio —Continued.

(8)

(7)

(10)

(6)

0

400

100

200

300

ALKALINITY CONCENTRATION,

 IN MILLIGAMS PER LITER

(8)

(7)

(10)

(6)

0

500

100

200

300

400

BICARBONATE CONCENTRATION,

 IN MILLIGRAMS PER LITER

AB B AB A ABC B AB C
30 Ground-Water Quality in Geauga County, Ohio

(8)

(7)

(10)

(6)

3.0

0

0.5

1.0

1.5

2.0

2.5

(8)

(7)

(10)

(6)

0

1.6

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

0

2,500

500

1,000

1,500

2,000

IRON CONCENTRATION, AMMONIA CONCENTRATION,

NITRATE CONCENTRATION,

 IN MICROGRAMS PER LITER IN MILLIGRAMS PER LITER AS N

 IN MILLIGRAMS PER LITER AS N

(8)

(7)

(9)

(6)

AB A B AB

A B AB AB A B AC C

GLACIAL

POTTSVILLE

CUYAHOGA

BEREA

GLACIAL

POTTSVILLE

CUYAHOGA

BEREA

(8) (7)

(10)

(6)

0

1,400

200

400

600

800

1,000

1,200

BORON CONCENTRATION,

 IN MICROGRAMS PER LITER

AB A BC C

Detection Limit = 0.18 milligrams per liter

SMCL = 300 milligrams per liter

Figure 11. Boxplots of chemical constituents delineated by stratigraphic unit for the 1999 sampling in 

Geauga County, Ohio —Continued.

(8)

(7)

(10)

(6)

0

1,200

200

400

600

800

1,000

DISSOLVED SOLIDS CONCENTRATION,

 IN MILLIGRAMS PER LITER

A A A A

(8)

(7)

(10) (6)

6

20

8

10

12

14

16

18

SILICA CONCENTRATION,

 IN MILLIGRAMS PER LITER

A A A A

SMCL = 500 milligrams per liter
Stratigraphic Variation in Water Quality 31

(8)

(7)

(10)

(6)

0.2

1.6

0.4

0.6

0.8

1.0

1.2

1.4

1.6

ORGANIC CARBON CONCENTRATION,

 IN MILLIGRAMS PER LITER

A A A A

Figure 11. Boxplots of chemical constituents delineated by stratigraphic unit for the 1999 sampling in 

Geauga County, Ohio —Continued.

0

300

50

100

150

200

250

MANGANESE CONCENTRATION,

IN MICROGRAMS PER LITER

(8)

(7)

(9)

(6)

0

1,400

200

400

600

800

1,000

1,200

STRONTIUM CONCENTRATION,

 IN MICROGRAMS PER LITER

(8)

(7)

(9)

(6)

AB A AB B

SMCL = 50 milligrams per liter

A A A A

GLACIAL

POTTSVILLE

CUYAHOGA

BEREA

GLACIAL

POTTSVILLE

CUYAHOGA

BEREA
32 Ground-Water Quality in Geauga County, Ohio

centrations is that the top of the open interval in the 

Pottsville wells is much nearer the water table than the 

top of the open interval in the other three units (fig. 

12). Unusually high total coliform concentrations were 

found in the Pottsville Formation at wells GE-332 and 

GE-23 

(100 col/100 mL and 53 col/100 mL, respectively). 

Elevated concentrations of dissolved oxygen, nitrate, 

and total coliform are indicative of recently recharged 

waters. 

Second, less variation is found in this formation 

than in the other three units for specific conductance, 

sodium, potassium, sulfide, sulfate, chloride, bromide, 

dissolved solids, ammonia, boron, iron, and strontium. 

Low values of specific conductance and dissolved solids generally indicate that ground water was recently 

recharged and has not had much time to interact with 

the aquifer minerals. The low variability and concentrations of ammonia, iron, and sulfide can be 

explained in that the waters generally are oxygenated, 

and these constituents either precipitate or change to 

another form in the presence of oxygen. The low variability of the other constituents relative to the Cuyahoga and Berea waters likely results because the 

Pottsville Formation is the uppermost bedrock unit 

and is not affected by varying degrees of stratigraphic 

confinement as are waters in the Cuyahoga Group and 

Berea Sandstone. 

The median value of pH in the Pottsville waters 

is below the SMCL range required by OEPA (1994) 

for drinking waters. Richards (1981) previously noted 

this problem in the area of South Russell Village and 

attributed the low pH values in the Pottsville to a combination of acidic precipitation and short ground-water 

residence times. Because short ground-water residence 

times do not allow for much dissolution of carbonate 

minerals from the aquifer materials, one result is minimal neutralization of acidic recharge from precipitation. 

Cuyahoga Group. Waters of the Cuyahoga 

Group are noteworthy mainly for their great variability 

in concentrations of various constituents (sodium, 

potassium, bicarbonate, alkalinity, chloride, silica, 

ammonia, iron, and strontium). As stated previously, 

erosion of the Pottsville Formation in some areas has 

left the Cuyahoga overlain only by thin glacial deposits in some areas and by as much as 200 ft of Pottsville 

Formation in other areas. Eberts and others (1990) 

found that variation in chemical concentration in the 

Cuyahoga Group was related to the length of the open 
Controls on Water Quality 33

interval of the well, the hydraulic conductivity of the 

open interval, and the presence of overlying permeable 

glacial deposits. 

Like the Pottsville waters, some Cuyahoga 

waters have a pH less than the lower limit of 7.0 

required by OEPA (1994) for drinking water. The lowest pH found in any stratigraphic unit was in the Cuyahoga Group—a pH of 4.7 at well GE-341. Median iron 

and manganese concentrations in the Cuyahoga Group 

both exceed the respective SMCLs.

Berea Sandstone. Ground water within the 

Berea Sandstone can be distinguished from that of the 

other units on the basis of median constituent concentrations. Median concentrations of sodium, bicarbonate, alkalinity, ammonia, boron, and strontium in the 

Berea Sandstone are greater than those in the other 

three units and are significantly greater than those of 

the Pottsville Formation. The highest specific conductance and concentrations of hardness, calcium, magnesium, sulfate, and dissolved solids were found in 

ground-water samples from the Berea Sandstone. High 

concentrations of dissolved solids are consistent with 

the longer ground-water residence times in the Berea 

(70 to 4,800 years relative to residence times in the 

Pottsville Formation of 15 to 170 years, as estimated 

by Eberts and others (1990)), which would allow for 

greater dissolution of aquifer minerals by ground 

water.

Data collected from wells completed in the 

Berea Sandstone contain some outliers. Well GE-159 

contains more sodium (180 mg/L), bromide 

(0.34 mg/L), and boron (1,250 mg/L) than was found 

in any other ground-water sample. The only sample to 

exceed the SMCLs for sulfate and dissolved solids is 

from the Berea Sandstone (well GE-122). 

Controls on Water Quality

In the preceding section, depth to top of the 

open (or sampling) interval was noted to affect concentrations of dissolved oxygen, nitrate, and iron. 

Concentrations of various constituents that were different at a statistically significant level between the 

Pottsville Formation and the Berea Sandstone were 

attributed to differences in the length of ground-water 

residence time. Other factors affecting the differences 

in ground-water chemistry, as noted in figures 10 and 

11, are discussed in the following paragraphs. Effects 

that are examined include geochemical processes and 

anthropogenic effects. 

Geochemical Processes. Geochemical processes can explain the evolution of the three water 

types grouped by dominant anion (bicarbonate-, sulfate-, and chloride-type waters), as shown in figure 10. 

One type of geochemical interaction between ground 

water and aquifer material is the dissolution and precipitation of minerals. Most waters in Geauga County 

are bicarbonate-type waters, with the dominant cations 

being calcium or calcium and magnesium. Dissolution 

of the carbonate minerals calcite and (or) dolomite is 

likely the process controlling the evolution of this 

water type. The glacial tills are one source of carbonate minerals in the area. Totten (1988) indicates that 

surficial tills in Geauga County are predominantly 

Hiram and Kent Tills. These tills contain more dolomite (3 to 10 percent by weight) than calcite (0.8 to 

4.5 percent by weight) (Ford, 1987; Szabo, 1987). 

As shown in figure 10, various samples of bicarbonate-type water contain greater than 20 relative percent sodium. A common process by which sodium is 

increased in bicarbonate water in aquifers containing 

abundant clay minerals is dissolution of carbonate 

minerals combined with cation exchange (Eberts and 

others, 1990; Lesney, 1992). Cation exchange is a process in which calcium and magnesium ions are 

removed from solution and replaced by sodium ions 

on exchangeable sites in clay minerals. As the reaction 

proceeds, the ratio of calcium ions to sodium ions 

remaining in solution decreases.

Marine shales, such as the Cuyahoga Group, 

contain both an abundance of clay minerals and 

sodium ions on cation-adsorption sites in the clays, a 

result of the original deposition of the clays in saltwater. Previous researchers (Eberts and others (1990) and 

Lesney (1992)) attributed sodium bicarbonate waters 

in the Cuyahoga Group and Berea Sandstone to cation 

exchange in the Cuyahoga Group, where the waters 

subsequently leaked downward into the Berea Sandstone. Data from the current study support the assumption that cation exchange is occurring in these 

stratigraphic units, because ratios of calcium to 

sodium are much lower for the Cuyahoga Group and 

Berea Sandstone (mean ratios of 1.5 and 0.79, respectively) than for the glacial deposits and Pottsville Formation (mean ratios of 3.6 and 6.1, respectively). 

Indeed, the samples collected from wells completed in 

the Berea Sandstone that contain the greatest proportion of sodium ions are also the only two wells where 

the Berea Sandstone is overlain by the Cuyahoga 

Group. Well GE-120, a mixed-cation bicarbonate 
34 Ground-Water Quality in Geauga County, Ohio

water, is overlain by 13 ft of shale, and well GE-159, a 

sodium bicarbonate water, is overlain by 168 ft of 

shale. 

Sodium bicarbonate-type water would be the 

end product of cation exchange over a long residence 

time. Although the current study found no waters from 

the Cuyahoga Group that are of the sodium bicarbonate type, other researchers (Eberts and others (1990) 

and Lesney (1992)) have found sodium bicarbonate 

water at some locations in the Cuyahoga Group. In the 

current study, sodium bicarbonate water was detected 

in well GE-159, which is completed in the Berea 

Sandstone in an area overlain by extensive shale 

deposits, and sodium bicarbonate water was also 

detected in well GE-321, in the glacial deposits. Well 

GE-321 has a total depth of 92 ft, and the open interval 

is overlain by 14 ft of clay and 45 ft of clayey sand 

interbedded with 30 ft of sand and gravel. The cation 

exchange in this area may occur as water flows past 

adsorption sites on the clays. Alternatively, waters 

already softened by cation exchange may discharge 

from the Berea Sandstone into the glacial deposits of 

the buried valley in which GE-321 is located.5

The calcium-magnesium sulfate-type water (fig. 

10) of well GE-122 may have evolved from dolomite 

dissolution by sulfuric acid. This is one process by 

which Lesney (1992) explained the evolution of calcium-sulfate-type water in glacial deposits of the 

lower Cuyahoga River Basin. Sulfuric acid is produced by the oxidation of pyrite (Nordstrom, 1982). 

Pyrite in unoxidized glacial deposits of northeastern 

Ohio has been reported by Sitler (1963). Pyrite oxidation causes carbonate minerals that are present in the 

aquifer materials to dissolve. Dissolving dolomite 

would release calcium, magnesium, sulfate, and bicarbonate to ground water. Dolomite dissolution by sulfuric acid, if allowed to proceed over a period of tens to 

hundreds of years, will produce calcium-magnesium 

sulfate-type waters (Eberts and George, 2000; Lesney, 

1992). 

Although waters from GE-122 were not dated, 

waters from this well likely have a long residence 

time. Well GE-122 is completed in the Berea Sandstone at the western edge of the county. A comparison 

of well location (fig. 1) with ground-water flowpaths 

in the Berea Sandstone (fig. 7) shows that GE-122 lies 

at the end of a long flowpath, near a discharge area for 

the Berea Sandstone. The residence time along such a 

flowpath would be on the order of 1,000 years, according to estimates by Eberts and others (1990). In areas 

upgradient from GE-122, the Berea is overlain by 

shales of the Cuyahoga Group that are as much as 200 

ft thick (Eberts and others, 1990). Cation exchange 

would be likely in such a setting. The calcium to 

sodium ratio of water at GE-122 is 2.9, well below the 

mean ratio of 6.1 for Pottsville waters that are unaffected by ion exchange.

The third type of water shown in figure 10 is 

chloride-type water or water of mixed anion type 

(mixtures of chloride, bicarbonate, and sulfate). Such 

waters are found in four samples (GE-23 and GE349A from the Pottsville Formation and GE-228 and 

GE-341 from the Cuyahoga Group). Chloride-type 

waters probably are the result of road salt and, in some 

cases, domestic sewage. Evidence supporting this conclusion is discussed in the “Anthropogenic Effects” 

section of this report.

Anthropogenic Effects. Constituents that 

were analyzed for during this study and that can have 

anthropogenic sources (table 6) include nitrate, bacteria, boron, VOCs, organic carbon, and chloride. No 

VOCs were detected during this study, and organic 

carbon concentrations were less than the 3 to 4 mg/L 

that may indicate the presence of hydrocarbons in 

ground water from sources such as leaking petroleum 

tanks or landfill leachate (Hem, 1989). 

Nitrate

Of the 31 samples from the current study, six had 

nitrate concentrations greater than 0.3 mg/L as N. 

Baker and others (1989) consider nitrate concentrations from 0 to 0.3 mg/L to represent background concentrations in Ohio (that is, concentrations that largely 

are unaffected by human activity). According to Baker 

and others (1989), concentrations of nitrate greater 

than 0.3 mg/L may represent anthropogenic effects. As 

shown in figure 13, all six nitrate detections were 

found at depths of less than 95 ft. Sample depth in this 

context refers to distance, in feet, from land surface to 

the top of the screened or open interval in the well. 

Five of the six wells in which nitrate was detected are 

completed in the Pottsville Formation. 

Three common anthropogenic sources of nitrate 

in ground water are large-scale feedlots, agricultural 

fertilizers, and leaking septic systems. Commercial 

feedlots are not prevalent in Geauga County, and much 

of the agricultural land in Geauga County is main5

The presence of a buried valley at this location is based on drillers’ 

logs of wells GE-321 and nearby well GE-126 compared to geologic 

sections from Eberts and others (1990).
Controls on Water Quality 35

Figure 13. Nitrate and total coliform concentrations and depth to the top of 

the open interval from land surface for ground-water samples collected in 

Geauga County, Ohio, 1999.

0 20 40 60 80 100 120

TOTAL COLIFORMS, 

0

250

50

100

150

200

0 0.5 1.0 1.5 2.0 2.5 3.0

NITRATE CONCENTRATIONS,

0

250

50

100

150

200

DEPTH TO TOP OF OPEN INTERVAL,

IN MILLIGRAMS PER LITER

IN FEET BELOW LAND SURFACE

DEPTH TO TOP OF OPEN INTERVAL,

IN FEET BELOW LAND SURFACE

Detection limit, 0.18 milligram per liter

GE-108

GE-228

GE-23

GE-332

GE-101

GE-141

GE-235

GE-202

GE-355

GE-185A

GE-120

GE-349A

OLD WATER—RECHARGED

YOUNG WATER—RECHARGED

TO AQUIFER AFTER 1953

TO AQUIFER BEFORE 1953

IN COLONIES PER 100 MILLILITERS

GE-332

GE-85A GE-341

GE-349A

GE-355

GE-23

YOUNG WATER—RECHARGED

TO AQUIFER AFTER 1953
36 Ground-Water Quality in Geauga County, Ohio

tained by small family operations and does not rely on 

large inputs of chemical fertilizer. Therefore, leaking 

septic systems are the most likely source for nitrate in 

ground water at concentrations above background levels. Most residents in the county rely on domestic septic systems to treat their wastewater. Leaking septic 

systems, in addition to elevating nitrate concentrations, can cause elevated concentrations of total 

coliforms, E. coli, boron, sodium, and chloride in 

ground water (table 6). 

 Total coliform bacteria

Supporting the idea of possible contamination 

from septic systems in the county is that total 

coliforms were detected in 16 of the 31 samples (52 

percent) from the current study. This detection rate of 

52 percent greatly exceeds the total coliform detection 

rate of 20 percent documented by Francy and others 

(2000) for 143 ground-water samples collected in five 

regions of the United States (including part of northern 

Ohio). Francy and others found a relation between the 

presence of septic systems on the property near the 

sampling site and the detection of coliforms; however, 

the relation was not statistically significant. 

Total coliforms are plotted as a function of depth 

in figure 13. Five of the six samples with total 

coliform concentrations greater than 10 col/100 mL 

are from wells with depths less than 55 ft from land 

surface to the top of the open interval. Water from 

these five wells all were categorized as young by tritium dating. The presence of coliforms in waters dated 

as old (GE-202, GE-120, and GE-108) is problematic 

because the lifespan of bacteria in the subsurface is 

considerably shorter than the age of these waters. As 

stated previously, old waters are considered to have 

recharged the aquifer before 1953. Bacteria survival 

times in the subsurface are on the range of days to 

years and are dependent on temperature, microbial 

activity, moisture content, pH, salt species and concentrations, soil properties, bacterium type, organic matter, and hydraulic conditions (Yates and Yates, 1988). 

The presence of total coliforms in old waters can be 

explained by either (1) the mixing of old waters with 

septic-system-affected young waters in such small 

amounts that the tritium concentrations of the mixture 

were not appreciably changed, or (2) introduction of 

bacteria into the distribution system from recent 

plumbing activities or some other type of intrusion. 

Because GE-108 is in glacial deposits in a buried valley that receives discharge from Cuyahoga Group, 

Berea Sandstone, and pre-Berea formations, this water 

may be a mixture of old and young waters.

Although nitrate, boron, and chloride are possible indicators of septic-system leakage (table 6), concentration of total coliforms in the current study does 

not correlate with nitrate, boron, or chloride concentration, as determined by use of nonparametric correlation techniques (Spearman’s rho = 0.21, -0.18, and 

-0.03, respectively). If nitrate and total coliforms in 

ground water are due to septic-system effects, concentrations would be expected to be greater in more 

densely populated areas. Macdonald (1987) found that 

mean nitrate concentrations were statistically higher at 

wells in densely populated areas than at wells in 

sparsely populated areas near South Russell Village. 

The current study found a moderate correlation 

between nitrate concentration and population density 

(Spearman’s rho =0.61) but a poor correlation between 

total coliform concentration and population density 

(Spearman’s rho = -0.10). 

Chloride-to-bromide ratios

Two other anthropogenic effects on ground-water 

quality in Geauga County are road salting (Jenkins, 

1987; Eberts and others, 1990; Lesney, 1992) and oilfield-brine disposal (MacDonald, 1987; Eberts and 

others, 1990). The county receives, on average, more 

than 100 in. of snowfall each year, so use of road salt 

to keep the roads clear is a common practice. 

One technique to identify sources of chloride in 

ground water is the comparison of weight ratios of 

chloride and bromide concentrations in a sample 

(Whittemore, 1988; Knuth and others, 1990; Davis 

and others, 1998). Chloride and bromide are useful 

indicators because they are both (1) highly soluble, (2) 

minimally affected by adsorption to sediment once 

dissolved in water, (3) not altered by oxidation-reduction reactions, and (4) not found in high concentrations 

in common rock-forming minerals with the exception 

of evaporite minerals such as halite (NaCl) (Feth, 

1981). Differences in ratios of chloride to bromide 

occur because bromide is even more soluble in water 

than chloride is (Davis and others, 1998). As seawater 

evaporates, halite (NaCl) in the residual water 

becomes saturated and precipitates (crystallizes) first, 

leaving a residual brine6

 in which bromide has concentrated. If this halite (either as a natural rock salt 

6

Brine is defined as water having a dissolved-solids concentration 

greater than 100,000 mg/L (Eberts and others, 1990).
Controls on Water Quality 37

CHLORIDE CONCENTRATION, IN MILLIGRAMS PER LITER

Cl : Br RATIO

Glacial deposits

Pottsville Formation

Cuyahoga Group

Berea Sandstone

Domestic sewage

Brine

Saturated halite solution

GE-341

GE-23

GE-228

GE-174A

GE-234

GE-141

GE-321

GE-159

GE-165

GE-355

GE-108

GE-349A

Domestic

Sewage

Theoretical upper Cl:Br

limit for waters not influenced

by anthropogenic sources

Dilute

ground water

Domestic sewage + halite Ground water + halite

Ground water + brine, upper limit

Ground water + brine, lower limit

Local oil-field

brines

Cl:Br range indicating

probable effects of

anthropogenic sources

Cl:Br range indicating

possible effects of

anthropogenic sources

EXPLANATION

Figure 14. Binary mixing curves for chloride to bromide (Cl:Br) ratios, Geauga County, Ohio, 1999. 

(Halite end-member from Knuth and others, 1990; domestic sewage end-member from Davis and 

others, 1998, and Peavy, 1978; brine end-member from Eberts and others, 1990.)

Young water, <1.8 TU

Old water, >1.8 TU

0.1 1 10 100 1,000 10,000 100,000 1,000,000

10

10,000

100

1,000
38 Ground-Water Quality in Geauga County, Ohio

deposit or as halite applied as road salt) is subsequently dissolved in freshwater, the water will become 

enriched in chloride relative to bromide and will thus 

have a high chloride-to-bromide (Cl:Br) ratio. Residual brines, which can be found in deep aquifers as fossil water that was trapped at the time of rock 

deposition, will be enriched in bromide relative to 

chloride and will have a much lower Cl:Br ratio 

(Davis and others, 1988). Such residual brines often 

are brought to land surface as a by-product of oil-andgas production.

Simple binary mixing curves (fig. 14) were prepared, following methods described in Whittemore 

(1988), to show how the Cl:Br ratio of dilute ground 

water would change with the addition of increasing 

amounts of three concentrated solutions: saturated 

halite solution, oilfield brine, and domestic sewage. 

These solutions, as well as the dilute, unaffected 

ground water, are referred to as “end-members” 

because they represent the starting and stopping points 

of the possible mixing process.

The sample from well GE-108 was chosen as 

the dilute ground water end-member because it had the 

lowest Cl:Br ratio and the lowest chloride concentration. Water from this well also contains no detectable 

tritium; thus, this water has a component of old water 

that recharged the aquifer prior to 1953. The Cl:Br 

ratio of the brine end-member was estimated as the 

mean of three samples of brine collected by Eberts and 

others (1990) from local oil and gas wells. The Cl:Br 

ratio of the saturated halite solution was computed as 

the mean of three samples of road salt applied in 

northeastern Ohio (collected by Knuth and others, 

1990).

The Cl:Br ratio of the domestic sewage endmember was selected as the midpoint of the range 

(300-600) reported by Davis and others (1998), based 

on limited analyses of urban sewage from England and 

the United States. The chloride concentration of the 

sewage end-member was estimated as the midpoint of 

the range (37-101 mg/L) reported by Peavy (1978; 

cited in Canter and Knox, 1986). 

Mixing curves were calculated by use of the following mixing equation (Whittemore, 1988): 

,

where

Cmix is the concentration of bromide (or chloride) in the mixture,

C1 is the concentration of bromide (or chloride) 

in the first end-member water,

C2 is the concentration of bromide (or chloride) 

in the second end-member water, and

V is the volume fraction of the first end-member 

water. 

Upper and lower limits were added to the ground 

water plus brine mixing curve by adding 15 percent to 

the end-member value to account for natural variation 

and analytical error. 

The shaded area designated as dilute ground 

water in figure 14 is based on Cl:Br ratios reported by 

Davis and others (1998) and on chloride concentrations reported by Jones and Sroka (1997). Davis and 

others (1998) reported that shallow ground water, 

unaffected or only minimally affected by dissolution 

of halite, generally has a Cl:Br ratio of 100 to 200. 

Davis and others (1998) also reported that Cl:Br ratios 

of atmospheric precipitation are generally between 50 

and 150, with ratios highest near the coast and 

decreasing inland. Jones and Sroka (1997) estimated 

that shallow wells in Ohio that were unaffected by 

halite dissolution had chloride concentrations less than 

10 mg/L. The water samples tritium dated as old and 

the other samples in the shaded area at the lower lefthand corner of the plot (fig. 14) have ratios consistent 

with dilute, shallow ground water originating as precipitation and unaffected or only minimally affected 

by the dissolution of halite. Where the limits of the 

dilute ground-water area (as drawn) cross the mixing 

curves, waters contain less than 0.01 percent saturated 

halite solution, less than approximately 15 percent 

domestic sewage, and less than 0.01 percent oilfield 

brine. 

Mixing of potable ground water with oilfield 

brines is not a widespread problem in the county (fig. 

14). Localized problems are present, however. Only 

one well from the current study, GE-165, falls along 

the mixing curve between dilute ground water and 

brine (volume of brine is 0.01 percent, or 100 ppm). 

This well is completed in glacial deposits. Eberts and 

others (1990) sampled another well (GE-105, Hambden Township, completed in Cuyahoga Group) that 

was not analyzed during the current study with Cl:Br 

ratios indicative of mixing with oilfield brine. Eberts 

also sampled three additional wells to investigate 

homeowner complaints of brine contamination. These 

three wells had Cl:Br ratios consistent with ground 

water affected by a mixture of oilfield or residual brine 

and halite. Well GE-159 (Berea), from the current 

Cmix = ( ) C1 × V + C2 1( ) – V
Controls on Water Quality 39

Figure 15. Chloride concentrations and depths of wells sampled in Geauga County, Ohio, 1999.

0 20 40 60 80 100 120 140 160 180 200 220 240 260

CHLORIDE CONCENTRATIONS, 

0

260

20

40

60

80

100

120

140

160

180

200

220

240

IN MILLIGRAMS PER LITER

IN FEET BELOW LAND SURFACE

DEPTH TO TOP OF OPEN INTERVAL,

study, may represent such a mixture. Well GE-321 

(glacial) may represent a mixture of dilute ground 

water, domestic sewage, and oilfield or residual brine. 

Although the young water from this well completed in 

glacial deposits plots very near the range of Cl:Br 

ratios and chloride concentrations in domestic sewage, 

well GE-321 contains no detectable nitrate or total 

coliform frequently associated with sewage.

Other wells outside of the “dilute ground water” 

area lie near or between the mixing lines of dilute 

ground water with either halite or domestic sewage. In 

Geauga County, halite is found only in salt deposits at 

great depth (about 2,100 ft below land surface). 

Because ground-water flow through the Cuyahoga 

Group is predominantly downward and because a 

graph of chloride concentration in ground water and 

depth shows that concentrations are generally higher 

near land surface (fig. 15), halite in these waters must 

originate from anthropogenic sources rather than as 

upflow of deep waters that have previously seeped 

through the deep salt deposits. Anthropogenic sources 

of halite could be road salt or the high-chloride-content water produced during the regeneration of watersoftening systems. The water used for regenerating the 
40 Ground-Water Quality in Geauga County, Ohio

water softening system is often discharged to septic 

systems, storm drains, or ditches (Thomas, 2000). 

Domestic sewage in Geauga County would enter the 

ground-water system by way of malfunctioning septic 

systems. 

The cutoff for what are considered “dilute 

ground waters” is rather subjective, so no definitive 

statements can be made regarding anthropogenic 

effects on waters that have Cl:Br ratios between 200 

and 400. When Cl:Br ratios fall within this range, 

other factors can be evaluated to determine anthropogenic effects. For example, ground water containing 

greater than the background concentration of 0.3 mg/L 

of nitrate may have been affected by human activities 

(Baker and others, 1989). This criterion can be applied 

to well GE-355, where a nitrate concentration of 

2.5 mg/L indicates possible anthropogenic effects but 

the Cl:Br ratio of 217 does not definitively point to 

anthropogenic sources.

Waters having Cl:Br ratios greater than 400 and 

plotting near or between the mixing lines are considered to have been affected by anthropogenic sources 

such as road-salt application or leakage from septic 

systems. No samples from the Berea Sandstone fall 

into this range, but each of the three other formations 

have at least one sample that are within the range. The 

age of waters in this category, if known, are young. 

Wells plotting to the right of the “ground water + 

halite” mixing curve (GE-23, GE-141, GE-228, GE349A) contain total coliform bacteria, consistent with 

input from a domestic sewage source. Well GE-349A 

also contains 2.2 mg/L of nitrate, also consistent with 

a sewage source. Waters plotting just to the left of the 

“ground water + halite” line in the Cl:Br range of 

probable anthropogenic effects (GE-174A, GE-234, 

GE-341) contain no total coliform bacteria. Association of bacteria with road-salt sources would not be 

expected. Only well GE-341 in this group contains 

detectable nitrate concentrations. Nitrate in this well 

could come from runoff of dissolved fertilizer. 

Samples whose Cl:Br ratios indicate effects of 

road salt are indicated in figure 16, which shows chloride concentrations and of distance from the sampled 

well to the road. A nonparametric correlation analysis 

of these data shows that chloride concentration is 

moderately correlated to distance of the well from the 

road (Spearman’s rho = -0.48, p = 0.0067).

In summary, leaking septic systems are a possible source of nitrogen at concentrations greater than 

background (0.3 mg/L). These concentrations were 

found in 6 of the 31 samples, predominantly in those 

from the Pottsville Formation. The presence of total 

coliform bacteria in 16 of the 31 samples provides 

additional evidence that septic-system wastes may be 

affecting ground water, particularly in the glacial 

deposits and Pottsville Formation. Ratios of chloride 

to bromide indicate that dilute ground water, domestic 

sewage, and road salt may be mixing in four locations, 

possibly more; however, conclusive evidence of sewage in ground water is precluded by the absence of E. 

coli in ground water and the absence of correlations of 

total coliform concentrations to nitrate, boron, and 

chloride concentration.

Road salt was found to affect ground-water 

quality in a total of eight samples from wells completed in the glacial deposits, Pottsville Formation, 

and Cuyahoga Group. Ratios of chloride to bromide 

for the samples indicate that they are mixtures of 

dilute ground water with (1) a halite (salt) solution, or 

(2) domestic sewage and halite (as indicated in the 

preceding paragraph). Chloride concentration in 

ground water is somewhat inversely correlated to distance of the well from the road.

Of the anthropogenic inputs affecting groundwater quality as noted above, only total coliform bacteria are present at concentrations that exceed a healthbased drinking-water standard and thereby diminish 

the suitability of ground-water for drinking. Influences 

of road salt and sewage in well GE-23 contribute to 

the exceedance of the esthetically based SMCL for 

dissolved solids at this location.

Temporal Variations in Water Quality

Two of the many reasons that changes in water 

quality can occur over time are (1) effects of human 

activities, and (2) increased pumping of an aquifer, 

which may begin to draw water from different sources 

(such as leakage from other aquifers, water from 

deeper zones, and induced infiltration of surface 

water). To determine whether water quality has 

changed over time in Geauga County, wells that were 

previously sampled by USGS personnel in 1978 

(Nichols, 1980) and in 1986 (Eberts and others 1990) 

were considered for resampling. 

Reasons why the 1978 and 1986 data provide a 

good baseline for comparison with current data were 

discussed previously (in the “Methods of Study” section). The main limitation of the use of these data as a 

baseline is the impermanence of wells. (This also is a 

limitation of the current study.) Because ground-water 
Temporal Variations in Water Quality 41

DISTANCE OF WELL FROM ROAD, IN FEET

CHLORIDE CONCENTRATIONS,

Figure 16. Chloride concentration and distance of well from road for samples collected in Geauga 

County, Ohio, 1999. (Labeled data poits are samples having a Cl : Br ratio as shown in figure 14

that indicates effects of road salt.) IN MILLIGRAMS PER LITER

0 500 1,000 1,500 2,000 2,500 3,000 0

260

20

40

60

80

100

120

140

160

180

200

220

240

GE-23

GE-341

GE-228

GE-349A

GE-174A

GE-234

GE-141

flowpaths in the county are localized (fig. 6), the best 

comparisons over time are from the same wells. 

Although every effort was made to resample as 

many of the same wells as possible, only 16 of the 

wells that were sampled in 1986 could be resampled 

for the current study and none of the wells sampled in 

1978 could be resampled. The number of resampled 

wells was limited because many of the wells that were 

sampled in previous years were either destroyed, were 

fitted with hand pumps from which a representative 

sample could not be obtained, or were inaccessible 

because new property owners would not allow the 

USGS to sample the well in 1999. The 16 wells that 

were sampled in both 1986 and 1999 were plotted on a 

population-density map (fig. 4), and none of the wells 

falls in an area where the population exceeds 250 people per square mile. Therefore, this limited data set 

reflects temporal variation in the quality of the water 

from rural areas, but it is probably not a good representation of the temporal variation caused by human 

activity in the villages of Geauga County where population density exceeds 250 people per square mile. The 

only way to obtain reliable, comparable data documenting changes in water quality caused by long-term 
42 Ground-Water Quality in Geauga County, Ohio

population growth would be to install and maintain 

monitoring wells in areas subject to growth. Temporal 

comparisons could not be made in some townships 

(fig. 4). 

Six constituents detected in both 1986 and 1999 

are likely affected by inputs such as road salt, septic 

leakage, and fertilizer: potassium, ammonia, sulfate, 

chloride, sodium, and bromide. Bacteria and nitrate 

data, which also are indicative of changes in human 

inputs, could not be used in the analysis of temporal 

variation in ground-water quality. (Bacteria data from 

the two years were not comparable; fecal coliform 

bacteria and fecal streptococci bacteria, which were 

analyzed for in 1986, no longer have an associated 

regulatory standard; therefore, the 1999 samples were 

analyzed for bacteria that are currently regulated by 

OEPA. Wells in which nitrate was detected in 1986 

could not be resampled in 1999, and wells in which 

nitrate was detected in 1999 were all wells that had not 

been previously sampled.) Boxplots and basic statisticsof the six constituents, grouped by year, are shown 

in figure 17 and listed in table 7. The boxplots and 

basic statistics did not reveal any significant changes 

over time that could be attributed to anthropogenic 

sources. 

For a more robust analyses of the data, two statistical tests were done, a standard two-sample t-test 

and a nonparametric Wilcoxon Rank Test. The two 

statistical analyses were done on pH, dissolved oxygen, specific conductance, all the major ions, iron, 

manganese, strontium, and bromide. At a 95-percent 

confidence level, none of these water-quality characteristics demonstrated a significant difference from 

1986 to 1999.

 

Table 7. Summary ground-water-quality statistics for waters from 16 wells sampled in 1986 and 

1999, Geauga County, Ohio

[Abbreviations: <, less than. Standard p-value is the value given for a standard t-test with the hypothesis that the mean of the two samples are the same, 

assuming a normal distribution. The Wilcoxon p-value uses the same hypothesis but does not assume a normal (Gaussian) distribution]

Minimum Maximum Mean Standard 

p-value

Wilcoxon 

p-value

Potassium 1986 0.1 6.4 2.24 0.89 0.92

Potassium 1999 .2 5.9 2.16

Ammonia 1986 .03 1.4 .37 .85 .88

Ammonia 1999 <.03 1.4 .41

Sulfate 1986 .90 660 90.6 .82 .86

Sulfate 1999 .14 535 79.2

Chloride 1986 .80 53 9.49 .49 .29

Chloride 1999 1.0 52 12.7

Sodium 1986 3.40 190 47.8 .84 .93

Sodium 1999 3.4 180 44.4

Bromide 1986 <.015 .34 .074 .94 .95

Bromide 1999 .02 .34 .076
Temporal Variations in Water Quality 43

(16) (16)

1986 1999 0

0.4

0.1

0.2

0.3

(16)

(16)

0

800

200

400

600

(16)

(16)

0

8

2

4

6

(16) (16)

1986 1999

0

60

10

20

30

40

50

(16) (16)

0

1.6

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

POTASSIUM, 

IN MILLIGRAMS PER LITER

AMMONIA, 

IN MILLIGRAMS PER LITER

SULFATE,

 IN MILLIGRAMS PER LITER BROMIDE,

 IN MILLIGRAMS PER LITER

CHLORIDE,

 IN MILLIGRAMS PER LITER

EXPLANATION

25th percentile

Median

75th percentile

interquartile range outside the quartile

Data value less than or equal to 1.5 times the

interquartile range outside the quartile

and more than 1.5 times the

Outlier data value less than or equal to 3

interquartile range outside the quartile

Outlier data value more than 3 times the

(8) Number of observations

Figure 17. Boxplots of chemical constituents at 16 wells sampled in 1986 and 1999, Geauga County, 

Ohio. (Results of Tukey’s t-test are represented as letters, and concentrations with at least one letter in 

common do not differ significantly at the 95-percent level.)

(16) (16)

0

200

50

100

150

SODIUM,

 IN MILLIGRAMS PER LITER

A A A A

A A A A

A A A A
44 Ground-Water Quality in Geauga County, Ohio

SUMMARY AND CONCLUSIONS

In 1995, Geauga County residents used 6.82 Mgal/day 

of ground water. Ground water is the primary source 

of drinking water for almost 80 percent of the population of Geauga County. To address potential concerns 

about quality of ground water in Geauga County and 

to evaluate what effect human activities have on 

ground-water resources, the USGS, in cooperation 

with the Geauga County Planning Commission and 

Board of County Commissioners, assessed water quality in the county in 1999 and compared these data to 

water-quality data collected by the USGS in 1986 and 

to data collected by other previous researchers. 

Previous studies of ground-water quality in the 

county (Ohio Environmental Protection Agency, 

1996a, 1996b, 1995, 1991, and 1984; Bolas and Mohr, 

1995; Lesney, 1992; Eberts and others, 1990; Baker 

and others, 1989; Jenkins, 1987; Macdonald, 1987; 

Grasso, 1986; Richards, 1981; Nichols, 1980) have 

been done for various purposes and at various scales. 

These studies, when considered jointly with the data 

obtained from the current study, provide an extensive 

data base on ground-water quality in Geauga County. 

The effects reported consistently throughout the studies include manganese and iron concentrations in 

ground water that often exceed the Secondary Maximum Contaminant Level. Road salt and, less commonly, oil-field brines have been found to affect 

ground water. Volatile organic compounds (VOCs) 

have been found in ground water at isolated locations 

that were affected by leaking underground storage 

tanks containing gasoline or solvents. Nitrate has not 

been a widespread ground-water-quality problem and 

has not been detected above the Maximum Contaminant Level (MCL) of 10 mg/L as N; however, nitrate 

has been found in some locations at concentrations 

that may indicate effluent from septic systems or the 

effects of fertilizer application.

To gather information on the current quality of 

the ground water, the USGS collected 31 samples from 

domestic and commercial wells between June 7 and 

July 1, 1999, using standard field techniques. Samples 

were obtained from the four primary stratigraphic 

units used as water supply in the county: glacial 

deposits, the Pottsville Formation, the Cuyahoga 

Group, and the Berea Sandstone. All samples were 

analyzed for VOCs, sulfide, dissolved organic carbon, 

major ions, trace elements, alkalinity, total coliform 

and Escherichia coli bacteria. Fourteen of the samples 

were also analyzed for tritium. Water-quality data 

were used to determine (1) suitability of water for 

drinking, (2) age of ground water, (3) stratigraphic 

variations in ground-water quality, (4) controls on the 

quality of the water, and (5) changes in ground-water 

quality since 1986. 

Suitability of water for drinking was determined 

by comparing constituent concentrations documented 

during this study to Ohio Environmental Protection 

Agency drinking-water standards for public water supplies and to standards of the Geauga County General 

Health District. No samples contained nitrate at concentrations above the MCL of 10 mg/L as N. Neither 

were benzene, toluene, trichloroethylene, tetrachloroethylene, and xylene detected at concentration limits 

set at levels less than or equal to the MCLs for these 

constituents.

Esthetically based SMCLs were exceeded in the 

indicated number of wells for pH (8), sulfate (1), dissolved solids (3), iron (19), and manganese (18). More 

importantly, water from 16 of the 31 samples exceeded 

the Geauga County General Health District’s standard 

for newly constructed wells of 0 colonies of total 

coliform bacteria per 100 mL of water. The detection 

rate of 52 percent for total coliforms greatly exceeding 

the total coliform detection rate of 20 percent documented by Francy and others (2000) for 143 groundwater samples collected in five regions of the United 

States. The presence of total coliforms indicates that 

disease-causing organisms also may be in the water 

because of contamination from human or other animal 

wastes; however, contamination by sewage could not 

be confirmed because Escherichia coli bacteria, an 

indicator of fecal contamination, was not detected in 

any of the water samples.

Fourteen ground-water samples were qualitatively dated by use of tritium analyses. Most waters 

were considered to contain a component of water that 

was young, having reached the water table as precipitation after 1953. The young waters included two samples from the Cuyahoga Group—one at a location 

where the Cuyahoga Group is the uppermost bedrock 

unit and the other at a location where recharge is 

through the overlying Pottsville Formation. Three 

wells yielded old waters that recharged the water table 

prior to 1953. This category included the only sample 

from the Berea Sandstone (GE-120) that was dated, as 

well as the only water collected from the Pottsville at a 

location where the shale unit of the Sharon Member is 

present (GE-202). The third sample of old water was 
Summary and Conclusions 45

obtained from well GE-108, which is completed in the 

glacial deposits of a buried valley that receives discharge from the Cuyahoga Group and the Berea Sandstone. Waters at this location likely represent a mixture 

of old bedrock waters and young waters with a relatively low tritium concentration. The tritium data 

agree, to the extent that they could be compared, with 

the residence times estimated by Eberts and others 

(1990) by use of a three-dimensional, steady-state 

flow model in conjunction with a particle-tracking 

program. 

Variation in chemical composition of ground 

water by stratigraphic unit was evaluated by plotting 

major ions concentrations of the four principal stratigraphic units on a trilinear diagram. The data do not 

plot as distinct groupings by stratigraphic unit. A 

range of water types can occur within a single unit. 

Ground waters in Geauga County can be categorized in three groups on the basis of predominant 

anion type: bicarbonate-type waters, sulfate-type 

waters, and chloride-type water. Most waters, regardless of aquifer, are dominated by the bicarbonate 

anion. These bicarbonate-type waters contain a wide 

range of cation types. Bicarbonate-type waters dominated by the calcium- and calcium-magnesium cations 

are formed by dissolution of the carbonate minerals 

calcite and dolomite. 

Bicarbonate-type waters that include sodium as 

a major cation are found in every stratigraphic unit 

except the Pottsville Formation. These sodiumenriched waters are formed when calcium- or calciummagnesium bicarbonate-type waters undergo cation 

exchange, a geochemical process in which calcium 

and magnesium ions produced by carbonate dissolution are removed from solution and replaced by 

sodium ions on exchangeable sites in clay minerals. 

As the reaction proceeds, the ratio of calcium ions to 

sodium ions remaining in solution decreases. Data 

from the current study support the idea that cation 

exchange is occurring in the Cuyahoga Group, with 

waters subsequently leaking downward into the Berea 

Sandstone. Calcium-to-sodium ratios are much lower 

for the Cuyahoga Group and Berea Sandstone (ratios 

of 1.5 and 0.79, respectively) than for the Pottsville 

Formation (6.1). Calcium-to-sodium ratios for the glacial deposits (3.6) are between the ratios for the Pottsville Formation and the deeper bedrock units 

(Cuyahoga Group and Berea Sandstone), because glacial deposits in buried valleys likely consist of calcium-bicarbonate-type waters that are mixing with 

sodium-bicarbonate-type waters that discharge from 

the Berea Sandstone and Cuyahoga Group into the 

buried valley. 

The only calcium-magnesium-sulfate-type 

water was obtained from well GE-122 in the Berea 

Sandstone. This water was likely formed by oxidation 

of pyrite and concurrent dissolution of dolomite over a 

period of tens to hundreds of years. 

Chloride-type waters were found in four samples (GE-23, 228, 341, and 349A). These waters from 

the Pottsville Formation and Cuyahoga Group were 

formed by inputs of road salt and, in some cases, 

domestic sewage. This origin is supported by ratios of 

chloride to bromide for these samples. Chloride-tobromide ratios indicate that four additional non-chloride-type waters also are affected by road salt. Chloride concentration of ground water is somewhat 

inversely correlated to distance of the well from the 

road (Spearman’s rho = -0.48, p =.0067).

Leaking septic systems are a possible source of 

nitrogen at concentrations greater than background 

(0.3 mg/L). These concentrations were found in 6 of 

the 31 samples. Ratios of chloride to bromide indicate 

mixing of dilute ground water, domestic sewage, and 

road salt at four of the sample locations, perhaps more. 

The detection of total coliforms in 16 of the 31samples 

further supports the idea that fecal wastes may be 

affecting county ground waters, although the absence 

of E.coli in the waters that were sampled precluded a 

definitive statement regarding contamination by sewage. Evidence of sewage in ground water is further 

complicated by the absence of correlation between 

concentration of total coliforms and nitrate, boron, and 

chloride concentration, as determined by use of nonparametric correlation techniques (Spearman’s rho = 

0.21, -0.18, and -0.03, respectively). 

Water-quality data from the current study were 

also compared to data collected in 1986. The 1986 

study is a good baseline for comparison with the current study because (1) many of the properties and constituents analyzed for were the same, (2) a broad set of 

indicators for major water-quality issues was analyzed, (3) the same laboratory (U.S. Geological Survey National Water Quality Laboratory) was used, and 

most analytical methods were the same and, therefore, 

are comparable, (4) waters from the four major stratigraphic units in the county were analyzed, and (5) the 

study had good spatial distribution of samples across 

the county. The main limitation of the use of the1986 

study as a baseline is that the wells used are imperma-
46 Ground-Water Quality in Geauga County, Ohio

nent. (This is also a limitation of the current study). 

Only 16 of the wells that were sampled in 1986 could 

be resampled for this study because many of the wells 

were either destroyed, had hand pumps from which a 

representative sample could not be obtained, or were 

inaccessible because new property owners would not 

allow the USGS access to the well in 1999. 

Statistical analyses of the 16 wells that were 

sampled in both 1986 and 1999 did not indicate any 

significant temporal changes in water quality (at a 

95-percent confidence interval). Because none of the 

16 wells were in an area where the population exceeds 

250 people per square mile, conclusions from statistical analyses of the data set are applicable to temporal 

variation in the quality of the water from rural areas, 

but are probably not applicable to temporal variation 

caused by anthropogenic effects in the villages of 

Geauga County where population density exceeds 

250 people per square mile. 

REFERENCES CITED

Arnade, L.J., 1999, Seasonal correlation of well contamination and septic tank distance: Ground Water, v. 37, 

no. 6, p. 920-923.

Baker, Jack, 1964, Geology and ground-water resources of 

Geauga County, Ohio: Unpublished manuscript on file 

in Columbus, Ohio, office of the U.S. Geological Survey, 108 p.

Baker, B.B., Wallrabenstein, L.K., Richards, R.P., and 

Creamer N.L., 1989, Nitrate and pesticides in private 

wells of Ohio, a state atlas: Tiffin, Ohio, Water Quality 

Laboratory, Heidelberg College (Part 2. County summaries), p. 97-100.

Bolas, M., and Mohr, E., 1995, Interoffice memorandum—Manganese investigation,Village of Middlefield, Middlefield Township, Geauga County: 

Unpublished document on file in the Twinsburg, Ohio, 

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DATA TABLES
Data Tables 49

Table 5. Chemical characteristics of water samples collected in Geauga County, Ohio, June and July 1999

[Well locations are shown in figure 1; Abbreviations: <, less than; μS/cm, microsiemens per centimeter; col/100 mL, colonies per 100 milliliters; E.coli, 

Escherichia coli; mg/L, milligrams per liter; μg/L, micrograms per liter; TU, tritium units; one TU = 3.24 picocuries per liter; --, not analyzed; NEG, 

negative detection; boldface type in the station name indicates that water-quality data also were collected in 1986 (Eberts and others, 1990). Footnotes at end 

of table.]

Station 

name Date

Water level, 

depth

below land 

surface

(feet)

Depth

of well,

total (feet)

Specific

conductance

(μS/cm)

pH,

water, 

whole, field 

(standard 

units)

Temperature,

water 

(degrees

Celsius)

Oxygen,

dissolved

(mg/L)

Coliform, 

total,

water 

unfiltered

(col/100 mL)

E. coli, 

water, 

unfiltered

(col/100 

mL)

Hardness, 

total

(mg/l as 

CaCO3)

GLACIAL DEPOSITS

GE-101 06/24/99 24.39 48 665 7.1 11.4 0.1 120 <1 360

GE-108 06/28/99 49.92 132 326 7.8 11.8 .1 54 <1 130

GE-141 06/15/99 9.55 53 502 7.4 11.2 .4 19a <1 260

GE-157 06/23/99 8.53 36 485 7.6 12.0 .1 <1 <1 170

GE-165 06/08/99 10.72 56 427 7.4 10.5 .1 <1 <1 210

GE-174A 06/14/99 29.13 85 574 7.7 12.2 .1 <1 <1 240

GE-235 06/21/99 13.49 51 365 7.6 11.0 .1 9a <1 190

GE-321 06/22/99 31.21 92 719 7.8 11.7 .1 <1 <1 120

POTTSVILLE FORMATION

GE-23 06/29/99 18.20 40 1300 6.9 13.0 1.3 53 <1 500

GE-85A 06/15/99 64.89 140 334 6.8 12.3 6.4 1a <1 170

GE-109 06/15/99 76.66 105 511 7.4 12.0 .1 <1 <1 270

GE-119b 06/17/99 14.77 79 449 6.3 13.2 .1 <1 <1 .2

GE-151 06/08/99 86.26 148 431 7.3 11.4 .4 <1 <1 230

GE-202 06/22/99 30.28 74 514 7.3 11.7 .1 6a <1 270

GE-204 06/30/99 11.56 53 479 6.8 11.5 .1 <1 <1 260

GE-332 06/14/99 35.06 104 418 6.8 13.4 3.8 100 <1 200

GE-349A 07/01/99 25.59 49.5 338 6.0 11.2 8.3 1a <1 88

GE-355 06/30/99 19.88 71 586 7.0 10.9 4.0 8a <1 310

CUYAHOGA GROUP

GE-77 06/08/99 42.53 155 803 7.4 12.1 .1 <1 <1 360

GE-147 06/16/99 6.72 63 757 7.6 11.9 .1 1a <1 220

GE-185A 06/28/99 36.74 90 325 6.7 11.7 .1 4a <1 150

GE-228 06/30/99 4.70 65 605 7.0 12.4 .1 61 <1 260

GE-234 06/21/99 14.70 80 313 7.4 11.5 .4 <1 <1 120

GE-280 06/22/99 34.42 162 383 7.0 11.5 7.6 <1 <1 170

GE-341 06/23/99 6.81 120 556 4.7 12.7 1.5 <1 <1 72

BEREA SANDSTONE

GE-103 06/24/99 91.19 136 543 7.2 11.8 .1 <1 <1 240

GE-104 06/23/99 98.67 204 507 7.7 11.6 .1 <1 <1 170

GE-120 06/29/99 105.91 135 497 7.4 12.1 .2 6a <1 150

GE-122 06/07/99 63.80 135 1490 7.2 11.6 .1 1a <1 730

GE-126 06/17/99 120.65 200 608 7.4 11.6 .1 <1 <1 240

GE-159 06/16/99 41.77 286 749 8.7 12.8 6.9c 1a <1 7
50 Ground-Water Quality in Geauga County, Ohio

Table 5. Chemical characteristics of water samples collected in Geauga County, Ohio, June and July 1999 — 

Continued

[Well locations are shown in figure 1; Abbreviations: <, less than; μS/cm, microsiemens per centimeter; col/100 mL, colonies per 100 milliliters; E.coli, 

Escherichia coli; mg/L, milligrams per liter; μg/L, micrograms per liter; TU, tritium units; one TU = 3.24 picocuries per liter; --, not analyzed; NEG, 

negative detection; boldface type in the station name indicates that water-quality data were also collected in 1986 (Eberts and others, 1990). Footnotes at end 

of table.]

Station

name

Calcium, 

dissolved 

(mg/L as 

Ca)

Magnesium,

dissolved 

(mg/L as Mg)

Sodium, 

dissolved

(mg/L as Na)

Potassium,

dissolved

(mg/L as K)

Bicarbonate,

water, field

(mg/L as HCO3)

Carbonate, 

water, field

(mg/L as CO3)

Alkalinity,

water, field

(mg/L as 

CaCO3)

Sulfide,

total 

(mg/L as S)

Sulfate,

dissolved

(mg/L as 

SO4)

GLACIAL DEPOSITS

GE-101 97 29 8.1 1.7 320 0 270 1.2 97

GE-108 33 12 21 1.4 190 0 150 .06 14

GE-141 75 18 8.2 1.1 220 0 180 .05 53

GE-157 41 17 45 3.2 290 0 240 <.01 19

GE-165 63 13 9.0 .9 200 0 170 .01 37

GE-174A 67 18 23 2.6 220 0 180 <.01 52

GE-235 55 12 3.4 .8 190 0 150 <.01 34

GE-321 37 7.7 120 1.4 310 0 260 .04 5.7

POTTSVILLE FORMATION

GE-23 140 35 68 1.6 290 0 240 <.01 68

GE-85A 45 15 4.0 1.2 150 0 120 <.01 38

GE-109 70 22 5.6 1.0 260 0 210 <.01 47

GE-119b .06 .03 99 .2 130 0 110 .02 70

GE-151 62 17 3.5 .9 200 0 160 <.01 44

GE-202 72 23 7.8 1.6 300 0 240 .02 32

GE-204 74 18 4.5 1.2 250 0 200 .04 31

GE-332 55 15 5.0 1.4 180 0 150 .03 53

GE-349A 26 5.8 24 1.8 42 0 34 <.01 35

GE-355 87 24 5.9 .9 270 0 220 <.01 55

CUYAHOGA GROUP

GE-77 84 35 46 5.9 440 0 360 <.01 110

GE-147 55 20 90 5.4 340 0 280 .02 120

GE-185A 46 8.7 7.5 2.9 170 0 140 <.01 19

GE-228 77 17 21 1.8 170 0 140 .21 24

GE-234 33 10 15 3.2 130 0 100 .01 12

GE-280 46 14 12 1.9 200 0 160 .04 36

GE-341 21 4.6 67 2.4 5 0 4 <.01 20

BEREA SANDSTONE

GE-103 56 25 26 2.9 340 0 270 <.01 27

GE-104 40 16 50 2.7 300 0 250 .01 23

GE-120 38 14 57 2.4 300 0 250 <.01 10

GE-122 160 76 55 3.8 430 0 350 .07 530

GE-126 66 17 41 1.8 300 0 250 .20 48

GE-159 1.8 .54 180 1.0 280 60 330 .40 .1
Data Tables 51

Table 5. Chemical characteristics of water samples collected in Geauga County, Ohio, June and July 1999 — 

Continued

[Well locations are shown in figure 1; Abbreviations: <, less than; μS/cm, microsiemens per centimeter; col/100 mL, colonies per 100 milliliters; E.coli, 

Escherichia coli; mg/L, milligrams per liter; μg/L, micrograms per liter; TU, tritium units; one TU = 3.24 picocuries per liter; --, not analyzed; NEG, 

negative detection; boldface type in the station name indicates that water-quality data were also collected in 1986 (Eberts and others, 1990). Footnotes at end 

of table.]

Station

name

Chloride,

dissolved

(mg/L as Cl)

Bromide,

dissolved

(mg/L as 

Br)

Silica,

dissolved

(mg/L as 

SiO2)

Solids,

residue

at 180

degrees

Celsius,

dissolved

(mg/L)

Nitrogen,

nitrate,

dissolved

(mg/L as N)

Nitrogen,

nitrite,

dissolved

(mg/L as N)

Nitrogen,

ammonia,

dissolved

(mg/L as N)

Nitrogen,

ammonia +

organic,

dissolved

(mg/L as N)

Phosphorus,

dissolved

(mg/L as P)

GLACIAL DEPOSITS

GE-101 6.4 0.04 15 420 <0.18 <0.02 0.13 0.188 <0.02

GE-108 1.0 .03 13 207 <.18 <.02 .26 .266 <.02

GE-141 29 .04 11 306 <.18 <.02 .04 <.005 <.02

GE-157 2.7 .04 14 283 <.18 <.02 .54 .482 <.02

GE-165 20 .21 10 272 <.18 <.02 .04 <.005 <.02

GE-174A 41 .03 11 330 <.18 <.02 .06 <.005 <.02

GE-235 2.4 .03 13 203 <.18 <.02 .05 .117 <.02

GE-321 74 .28 13 418 <.18 <.02 .25 .208 <.02

POTTSVILLE FORMATION

GE-23 240 .21 15 820 .38 <.02 .03 <.005 <.02 

GE-85A 4.1 .03 12 220 .92 <.02 .03 <.005 <.02

GE-109 11 .04 12 286 <.18 <.02 .04 <.005 <.02

GE-119b 21 .02 11 283 <.18 <.02 <.03 <.005 <.02

GE-151 5.0 .04 10 267 <.18 <.02 .04 <.005 <.02

GE-202 4.5 .03 16 312 <.18 <.02 .13 .099 <.02

GE-204 3.2 .04 11 265 <.18 <.02 <.03 <.005 <.02

GE-332 8.3 .03 9.4 266 .98 <.02 .04 <.005 <.02

GE-349A 43 .05 8.0 231 2.2 <.02 <.03 <.005 <.02

GE-355 13 .06 11 321 2.5 <.02 <.03 .014 <.02

CUYAHOGA GROUP

GE-77 2.0 .06 17 507 <.18 <.02 1.4 1.19 <.02

GE-147 8.1 .09 15 480 <.18 <.02 .85 .786 <.02

GE-185A 10 .06 15 213 <.18 <.02 .20 .145 <.02

GE-228 93 .08 15 361 <.18 <.02 .10 <.005 <.02

GE-234 32 .02 11 194 <.18 <.02 .36 .335 <.02

GE-280 6.4 .03 16 260 <.18 <.02 .21 .233 <.02

GE-341 150 .03 7.4 338 1.4 <.02 .10 <.005 <.02

BEREA SANDSTONE

GE-103 1.2 .02 15 318 <.18 <.02 .37 .376 <.02

GE-104 4.3 .06 13 302 <.18 <.02 .70 .654 <.02

GE-120 8.1 .07 15 301 <.18 <.02 .65 .487 <.02

GE-122 9.5 .06 13 1100 <.18 <.02 1.3 1.27 .02

GE-126 21 .05 15 354 <.18 <.02 .16 <.005 <.02

GE-159 52 .34 7.2 479 <.18 <.02 .42 .330 <.02
52 Ground-Water Quality in Geauga County, Ohio

a Estimated count based on a non-ideal colony count. An ideal colony count, necessary for accurate enumeration, is greater than or equal to 20 and less 

than or equal to 80 colonies per filter.

b

 Although efforts were made to collect untreated water that would be representative of the aquifer, the high sodium concentration and unusually low 

concentrations of hardness, calcium, magnesium, iron, manganese, and strontium suggest that this water sample was artificially softened by ionexchange methods.

c

 Anomalously high dissolved oxygen concentration. Dissolved oxygen increased after 45 minutes of purging, but all other field parameters remained 

stable.

d

 Samples were screened by means of a portable gas chromatograph with a heated column and a calibration library consisting of benzene at 3 μg/L, 

trichloroethylene at 5 μg/L, toluene at 3 μg/L, perchloroethylene at 5 μg/L, and xylene at 13 μg/L. NEG means not detected at stated levels. e

 Estimated values are lower than the lowest calibration standard but higher than the detection limit of the machine.

Table 5. Chemical characteristics of water samples collected in Geauga County, Ohio, June and July 1999 

—Continued

[Well locations are shown in figure 1; Abbreviations: <, less than; μS/cm, microsiemens per centimeter; col/100 mL, colonies per 100 milliliters; E.coli, 

Escherichia coli; mg/L, milligrams per liter; μg/L, micrograms per liter; TU, tritium units; one TU = 3.24 picocuries per liter; --, not analyzed; NEG, 

negative detection; boldface type in the station name indicates that water-quality data were also collected in 1986 (Eberts and others, 1990). Footnotes at end 

of table.]

Station

name

Phosphorus,

ortho, 

dissolved

(mg/L as P)

Boron,

dissolved

(μg/L as B)

Iron,

dissolved

(μg/L as Fe)

Manganese,

dissolved

(μg/L as Mn)

Strontium,

dissolved

(μg/L as Sr)

Tritium,

total 

(TU)

Tritium 

precision

estimate

(TU)

Carbon,

organic,

dissolved

(mg/L 

as C)

Volatile

organic

compounds,

screen 

(μg/L)d

GLACIAL DEPOSITS

GE-101 <0.01 49.5 1600 120 250 9.6 ±1.4 1.0 NEG

GE-108 <.01 167 440 34 680 <1.8 ±1.0 .6 NEG

GE-141 <.01 27.3 890 200 110 13.0 ±1.4 .7 NEG

GE-157 <.01 336 290 15 790 -- -- 1.0 NEG

GE-165 <.01 18.3 1900 180 84 -- -- .3 NEG

GE-174A <.01 46.1 <10 120 140 -- -- 1.2 NEG

GE-235 <.01 19.8 630 72 100 -- -- .7 NEG

GE-321 <.01 413 360 92 96 9.2 ±1.4 1.4 NEG

POTTSVILLE FORMATION

GE-23 .01 36.5 10 2e 220 20.3 ±1.8 1.0 NEG 

GE-85A <.01 21.5 <10 <3 100 22.2 ±2.0 .6 NEG

GE-109 .02 25.9 300 110 250 16.2 ±1.6 .9 NEG

GE-119b <.01 25.0 18 6 <1 -- -- .9 NEG

GE-151 <.01 26.0 310 96 96 -- -- .3 NEG

GE-202 <.01 45.6 640 100 230 <1.8 ±1.0 .8 NEG

GE-204 .01 22.2 170 250 160 -- -- 1.0 NEG

GE-332 <.01 21.5 <10 <3 100 19.1 ±1.8 .9 NEG

GE-349A <.01 56.5 15 <3 88 14.6 ±1.6 .8 NEG

GE-355 .01 21.8 <10 <3 150 25.1 ±2.0 1.0 NEG

CUYAHOGA GROUP

GE-77 <.01 471 890 22 1300 -- -- .7 NEG

GE-147 <.01 473 490 9 700 -- -- 1.1 NEG

GE-185A .01 107 2100 190 160 15.5 ±1.6 .7 NEG

GE-228 .02 75.6 1900 180 150 14.4 ±1.6 .6 NEG

GE-234 <.01 335 560 69 260 -- -- .4 NEG

GE-280 <.01 86.5 1800 260 170 -- -- .8 NEG

GE-341 <.01 50.8 28 260 81 -- -- .7 NEG

BEREA SANDSTONE

GE-103 <.01 231 680 174 920 -- -- 1.0 NEG

GE-104 <.01 375 310 7 640 -- -- .8 NEG

GE-120 <.01 256 9e 25 360 <1.8 ±1.0 .8 NEG

GE-122 <.01 273 1200 63 1000 -- -- .6 NEG

GE-126 <.01 238 570 140 170 -- -- 1.1 NEG

GE-159 <.01 1250 <10 2e 37 -- -- 1.5 NEG
Data Tables 53

Table 6. Concentration limits defined by primary and secondary public drinking-water regulations and implications 

for domestic water use and ground-water geochemistry for selected properties and chemical constituents in water 

samples collected in Geauga County, Ohio, June and July, 1999

[USEPA, U.S. Environmental Protection Agency; OEPA, Ohio Environmental Protection Agency; MCL, Maximum contaminant level; SMCL, Secondary 

maximum contaminant level; DWEL, Drinking water equivalent level; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter; μg/L, micrograms 

per liter; CaCO3, calcium carbonate; TU, tritium units; mL, milliliters; E. coli, Escherichia coli; >, greater than. MCLs, SMCLs based on standards set by the 

Ohio Environmental Protection Agency (1994) and DWELs are based on standards set by the U.S. Environmental Protection Agency (2000). Geochemical 

implications of each water property as they relate to this study are modified from Dumouchelle and others (1993), the discussion of natural water chemistry 

given by Hem (1989) and Driscoll (1986), and a discussion of bromide/chloride ratios given by Davis and others (1998).]

Constituent or 

property

Concentration limits and water-use 

implications Implications for ground-water geochemistry

Specific conductance, 

μS/cm

Regulatory standards not established with 

respect to drinking water.

Proportional to total ionic concentration in solution. May be used to 

distinguish between different water types in an aquifer

pH, standard units The SMCL requires values between 7.0 and 

10.5. Values outside this range may be corrosive 

to metal well casings and pipes, creating costly 

replacement problems. A pH below 6.5 can 

generate health-related problems by dissolving 

small quantities of trace metals such as lead, 

especially in a house built before lead solder 

was banned in 1987.

General measure of the acidity or alkalinity of a water sample. One of 

the most important properties with respect to regulating the transport of 

metals, organics, and other dissolved constituents in ground water. Also 

controls dissolution-precipitation reactions in the aquifer.

Temperature, degrees 

Celsius

Regulatory standards not established with 

respect to drinking water.

Needed for speciation and saturation-state calculations. Can be used to 

identify recharge-discharge zones.

Dissolved oxygen, mg/L Regulatory standards not established with 

respect to drinking water.

Atmospheric oxygen dissolves in shallow ground water, and its presence 

at concentrations exceeding 0.5 mg/L indicates oxidizing conditions. 

Oxygen reacts with organic matter, nitrate, ferrous iron, or sulfidebearing minerals and is quickly removed from the aquifer. The presence 

of dissolved oxygen in deep parts of an aquifer indicates rapid recharge 

rates or a lack of oxidizable material (organic matter, sulfide minerals) 

in aquifer rocks and sediments.

Total coliform bacteria, 

colonies/100 mL

The MCL states that for systems with more than 

40 samples per month no more than 5 percent of 

the samples can be total coliform-positive. For 

water systems that collect fewer than 40 

samples per month, no more than one sample 

can be total coliform-positive. All total 

coliform-positve samples must be retested for 

fecal coliforms.

Total coliform bacteria are indicator organisms that, when present, 

indicate that there is a possibility, but not a certainty, that diseasecausing organisms may also be present in the water due to 

contamination from human or animal wastes. Coliform bacteria can also 

occur naturally in the soil, so their presence does not necessarily indicate 

a sewage-contamination problem or imminent health risk.

E. coli bacteria, 

colonies/100 mL

The MCL states that there can be no E.coli or 

other fecal coliforms in a well.

One species of bacteria in the total coliform group that originates only in 

the intestines of warm-blooded animals and humans. The presence of 

E.coli indicates that sewage wastes or other fecal material are present in 

the water.

Hardness, mg/L as 

CaCO3

Upon heating and evaporation, hard water 

precipitates carbonate mineral deposits, scale, 

and crusts on pipes, hot water heaters, boilers, 

and cooking utensils. Also causes increased 

soap consumption. Dufor and Becker (1964) 

give the following hardness classification:

Hardness range

(mg/L of CaCO3) Description

0 - 60 Soft

61 -120 Moderately hard

121 -180 Hard

More than 180 Very hard

Hardness is caused by high concentrations of calcium, magnesium, and 

to a lesser extent, strontium. Waters with hardness values greater than 

200 or 300 mg/L usually are associated with carbonate- or gypsumcontaining materials. 

Calcium, dissolved

mg/L

Regulatory standards not established with 

respect to drinking water. Major contributor to 

hardness and scale formation.

In carbonate-bearing aquifers, is derived from the dissolution of calcite 

or dolomite and in some instances, gypsum. Concentrations of calcium 

usually are regulated by equilibria with carbonate minerals such as 

calcite. Carbonate equilibria are, in turn, largely controlled by pH and 

the partial pressure of CO2. 

Magnesium, dissolved

mg/L

Regulatory standards not established with 

respect to drinking water. Contributes to 

hardness and scale formation. At high 

concentrations (>125 mg/L) may cause laxative 

effects, especially to transient users.

In carbonate-bearing aquifers, is derived from the dissolution of 

magnesium-bearing calcite or dolomite.
54 Ground-Water Quality in Geauga County, Ohio

Sodium, dissolved

mg/L

Regulatory standards not established with 

respect to drinking water, but is listed on the 

USEPA Drinking Water Contaminant Candidate 

List (CCL) as a Research Priority.

May be derived from the dissolution of sodium-bearing aluminosilicate 

minerals (such as albitic feldspar), or halite (NaCl) present in evaporite 

deposits. In carbonate aquifers, high sodium concentrations are often 

indicative of the effects of human activities such as road deicing, leaking 

septic tanks, or the disposal of brine pumped from oil wells. 

Potassium, dissolved

mg/L

Regulatory standards not established with 

respect to drinking water. No health or esthetic 

implications for the range of concentrations 

found in this study. 

Typically derived from the dissolution of potassium-bearing 

aluminosilicate minerals (such as potassic feldspar or micas). 

Concentrations typically are low because of the low reactivity of the 

potassium-bearing silicate minerals and the incorporation of potassium 

in clay minerals such as asillite (a common mineral in glacial-till 

deposits).

Bicarbonate, mg/L as 

HCO3

Regulatory standards not established with 

respect to drinking water.

Major contributor to alkalinity (see below). Is derived from the 

dissolution of carbonate minerals by carbonic acid (H2CO3). 

Carbonate, mg/L as CO3 Regulatory standards not established with 

respect to drinking water.

Minor contributor to alkalinity (see below).

Alkalinity, mg/L as 

CaCO3

Regulatory standards not established with 

respect to drinking water. No health or esthetic 

implications for the range of concentrations 

found in this study. Alkalinity is a measure of 

the capacity of a water to neutralize acid. 

In carbonate-bearing aquifers, almost all alkalinity results because of the 

presence of the bicarbonate ion (HCO3

-

). Minor contributors to 

alkalinity include the carbonate (CO3

2-) and hydroxide (OH-

) ions.

Sulfide, total

mg/L as S

Regulatory standards not established with 

respect to drinking water. Most people can smell 

the rotten-egg odor of hydrogen sulfide at a 

concentration of only 0.5 mg/L in cold water.

This form of sulfur is formed by sulfate-reducing bacteria that live in 

water that has a high sulfate content and the absence of oxygen. Under 

oxidizing conditions the sulfide can be converted back to sulfate.

Sulfate, dissolved

mg/L as SO4

The SMCL is 250 mg/L. Combines with 

calcium to form scale in water heaters and 

boilers. At concentrations exceeding 500-600 

mg/L, imparts a bitter taste and may cause 

laxative effects in some individuals. 

Derived from the dissolution of gypsum (CaSO4

.

2H2O) or the oxidation 

of sulfide minerals such as pyrite (FeS2). Stable under oxidizing 

conditions; however, under reducing conditions can be converted to 

hydrogen sulfide.

Chloride, dissolved

mg/L

The SMCL is 250 mg/L. At concentrations 

greater than 250 to 400 mg/L, imparts a salty 

taste to water depending on individual 

tolerance. High concentrations are corrosive to 

most metals.

Derived from the dissolution of halite. Is a rare constituent of nonevaporite rocks. High concentrations imply inputs of brines of natural 

origin or anthropogenic sources such as road salt or the disposal of brine 

pumped from oil wells. 

Bromide, dissolved

mg/L

Regulatory standards not established with 

respect to drinking water.

Derived from precipitation, dissolution of evaporites, or intrusion of 

brine from compacting clays. The ratio of chloride to bromide can be 

used to evaluate the origin of dissolved salts in ground water.

Silica, dissolved

mg/L

Regulatory standards not established with 

respect to drinking water.

Used to evaluate controls on silica concentration.

Dissolved solids, 

residue at 180oC

The SMCL is 500 mg/L. Concentrations greater 

than 1,000 mg/L may cause objectionable tastes 

and laxative effects. Also may cause foaming or 

may corrode some metals.

Proportional to dissolved ion concentrations. Like specific conductance, 

may be used to distinguish between different water types in an aquifer.

Nitrate, dissolved

mg/L as N

At concentrations greater than the MCL of 

10 mg/L as N, can cause “Blue baby syndrome” 

(methemoglobinemia) in infants under six 

months - life threatening without immediate 

medical attention.

Presence of nitrate indicates oxidizing conditions in the aquifer. 

Elevated concentrations are indicative of anthropogenic sources of 

nitrate (fertilizer, septic tank leakage) and indicate that the aquifer is 

vulnerable to infiltration of surface drainage. 

Nitrite, dissolved

mg/L as N

At concentrations greater than the MCL of 

1 mg/L as N, can cause “Blue baby syndrome” 

(methemoglobinemia) in infants under six 

months - life threatening without immediate 

medical attention.

Nitrite is unstable in oxidizing conditions and is an intermediate product 

in the reduction of nitrate to ammonia. Is an indicator of pollution 

through disposal of sewage or organic waste from a nearby source. 

Table 6. Concentration limits defined by primary and secondary public drinking-water regulations and implications 

for domestic water use and ground-water geochemistry for selected properties and chemical constituents in water 

samples collected in Geauga County, Ohio, June and July, 1999 —Continued

[USEPA, U.S. Environmental Protection Agency; OEPA, Ohio Environmental Protection Agency; MCL, Maximum contaminant level; SMCL, Secondary 

maximum contaminant level; DWEL, Drinking water equivalent level; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter; μg/L, micrograms 

per liter; CaCO3, calcium carbonate; TU, tritium units; mL, milliliters; E. coli, Escherichia coli; >, greater than. MCLs, SMCLs based on standards set by the 

Ohio Environmental Protection Agency (1994) and DWELs are based on standards set by the U.S. Environmental Protection Agency (2000). Geochemical 

implications of each water property as they relate to this study are modified from Dumouchelle and others (1993), the discussion of natural water chemistry 

given by Hem (1989) and Driscoll (1986), and a discussion of bromide/chloride ratios given by Davis and others (1998).]

Constituent or 

property

Concentration limits and water-use 

implications Implications for ground-water geochemistry
Data Tables 55

Ammonia, dissolved

mg/L as N

No health or esthetic implications for the range 

of concentrations found in this study.

Aqueous ammonia is unstable in oxidizing conditions. May also be an 

indicator of pollution through disposal of sewage or organic waste.

Ammonia + organic 

nitrogen, dissolved

mg/L as N

No health or esthetic implications for the range 

of concentrations found in this study.

Also called “Total Kjeldahl Nitrogen.” Organic species of nitrogen are 

unstable in aerated water. An indicator of pollution through disposal of 

sewage or organic waste from a nearby source.

Phosphorus, dissolved

mg/L

No health or esthetic implications for the range 

of concentrations found in this study.

Although a common minor element in most rocks, readily soluble forms 

are rare. Mobility in subsurface is low due to its ready adsorption by 

common metal oxide minerals. 

Orthophosphorus, 

dissolved

mg/L as P

No health or esthetic implications for the range 

of concentrations found in this study.

The most thermodynamically stable of the P5+ forms of phosphorus. Is 

an indicator of pollution from laundry wastewater, commercial cleaning 

wastes, or from sewage. Elevated concentrations also can indicate that 

the aquifer is vulnerable to infiltration of surface drainage containing 

fertilizer from agricultural areas.

Boron, dissolved

mg/L

Regulatory standards not established with 

respect to drinking water. No health or esthetic 

implications for the range of concentrations 

found in this study. Boron is essential for plant 

nutrition but is toxic to some plants at high 

concentrations.

Concentration of boron is not affected by adsorption, precipitation or 

dissolution reactions. It can therefore be used as a chemical tracer. 

Boron is present in high concentrations in most landfill leachate. Is also 

present in laundry detergent, and its presence in ground water can 

indicate contamination from leaking septic systems.

Iron, dissolved

μg/L

The SMCL is 300 μg/L. At concentrations 

exceeding the SMCL, iron contributes to 

staining of fixtures, utensils, and laundry. 

Higher concentrations form reddish-brown 

sediment and water-line deposits. At 

concentration greater than 1,800 μg/L the water 

has a metallic taste (Fetter,1980, p. 355).

General redox indicator. Dissolved-iron concentrations are below 

detection limits in oxygenated waters at near-neutral conditions. Under 

more reducing conditions, dissolved iron concentrations may exceed 

several milligrams per liter.

Manganese, dissolved

μg/L

The SMCL is 50 μg/L. At concentrations 

exceeding the SMCL, manganese may cause 

dark-brown or black staining of fixtures, 

utensils, and laundry. 

Concentrations controlled by various oxide and oxy-hydroxide mineral 

equilibria. Dissolution of manganese-oxide coatings on glacial aquifer 

material under reducing conditions is a likely source of dissolved 

manganese.

Strontium, dissolved

μg/L

USEPA health advisory guidance (DWEL) is 

20 mg/L.

Derived from the dissolution of calcite or dolomite in which Sr has 

replaced Ca in trace amounts, the carbonate mineral strontianite, or the 

sulfate mineral celestite. Elevated concentrations in ground water may 

indicate contamination by fertilizer and pesticide. Can also be used as an 

indicator of the origin of dissolved salts in ground water.

Tritium, total

TU

Regulatory standards not established. No health 

or esthetic implications for the range of 

concentrations found in this study.

Radioactive isotope of hydrogen introduced into the atmosphere in large 

quantities during the period of atomic bomb testing in early 1950’s and 

1960’s. Used to estimate approximate recharge age of ground water; to 

examine ground-water flowpaths; and to examine contributions to the 

glacial deposits from bedrock formations. 

Dissolved organic 

carbon, 

mg/L

Regulatory standards not established. No health 

or esthetic implications for the range of 

concentrations found in this study.

Concentrations greater than 3-4 mg/L are unusual for ground water and 

may indicate the presence of hydrocarbon compounds derived from 

human activities and vulnerability of the aquifer to surface drainage. 

Present at high concentrations in landfill leachate and in ground water 

affected by petroleum spills or leaks.

Volatile organic carbona Health—MCLs are as follows: benzene, 

5 μg/L; trichloroethylene, 5 μg/L; toluene, 

1 mg/L; tetrachloroethylene, 5 μg/L; and 

xylene, 10 mg/L.

Indicate the presence of hydrocarbon compounds derived from human 

activities and vulnerability of the aquifer to surface drainage. Present in 

ground water affected by petroleum spills or leaks.

a

Samples were screened using a portable gas chromatograph with a heated column and a calibration library consisting of benzene at 3 μg/L, 

trichloroethylene at 5 μg/L, toluene at 3 μg/L, tetrachloroethylene at 5 μg/L, and xylene at 13 μg/L. 

Table 6. Concentration limits defined by primary and secondary public drinking-water regulations and implications 

for domestic water use and ground-water geochemistry for selected properties and chemical constituents in water 

samples collected in Geauga County, Ohio, June and July, 1999 —Continued

[USEPA, U.S. Environmental Protection Agency; OEPA, Ohio Environmental Protection Agency; MCL, Maximum contaminant level; SMCL, Secondary 

maximum contaminant level; DWEL, Drinking water equivalent level; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter; μg/L, micrograms 

per liter; CaCO3, calcium carbonate; TU, tritium units; mL, milliliters; E. coli, Escherichia coli; >, greater than. MCLs, SMCLs based on standards set by the 

Ohio Environmental Protection Agency (1994) and DWELs are based on standards set by the U.S. Environmental Protection Agency (2000). Geochemical 

implications of each water property as they relate to this study are modified from Dumouchelle and others (1993), the discussion of natural water chemistry 

given by Hem (1989) and Driscoll (1986), and a discussion of bromide/chloride ratios given by Davis and others (1998).]

Constituent or 

property

Concentration limits and water-use 

implications Implications for ground-water geochemistry
56 Ground-Water Quality in Geauga County, Ohio

Appendix A: Quality Assurance/Quality Control
Appendix A: Quality Assurance/Quality Control 57

APPENDIX A: QUALITY ASSURANCE/

QUALITY CONTROL

Quality assurance/quality control (QA/QC) samples, 

including field blanks, duplicate samples, and sourcesolution blanks, were collected for most analytes at the 

rate of 10 percent to ensure sample integrity and final 

quality of data. Duplicate samples were collected to 

assess the reproducibility of the sample-collection procedures and laboratory and (or) field determination of 

constituent concentration, as well as to provide the 

data user with a measure of variability (Francy and 

others, 1998). Duplicate samples were collected 

immediately after the environmental sample from the 

same well by use of the same equipment and field 

methods. A total of three duplicate samples (one per 

week) were collected for analysis of the same constituents as the environmental samples. The exception was 

tritium, for which only one duplicate sample was analyzed. Duplicate samples were collected at sites where 

surrounding land use, well depth, and (or) housing 

density indicated that nitrate, VOCs, and (or) bacteria 

might be detected. These samples were collected at 

wells GE-119, GE-165, and GE-349A. The tritium 

duplicate sample was collected at a site where a 

detectable concentration of tritium in ground water 

also was expected. (Because two sample vials were 

sent to the laboratory for each VOC sample, the laboratory technician could run additional VOC duplicates 

if VOCs were detected at other well locations.)

A total of three field blanks were collected to 

identify bias caused by contamination from equipment, supplies, and ambient environmental conditions 

(Francy and others, 1998). The field blanks were collected at the same locations as the duplicate samples. 

After the environmental samples and duplicate samples had been collected and the equipment had been 

decontaminated, deionized water was gravity-fed 

through the sample tubing. For filtered samples, a 

peristaltic pump was used to provide enough pressure 

to push the water through the filter. A portion of the 

water was collected and preserved for chemical analysis of major ions, trace metals, and nutrients. Field 

blanks for VOCs were collected by use of organic-free 

water. This water was gravity-fed through the Teflon 

sample tubing. Blanks for dissolved organic carbon 

(DOC) were gravity-fed through the silicon sample 

tubing. The first 200 mL of water was discarded, and 

the subsequent water was forced through the DOC 

stainless steel filter cartridge by use of nitrogen gas. 

No blanks were analyzed for tritium. 

A total of two bottles of organic-free water were 

used in the process of preparing VOC and DOC field 

blanks. When each of these bottles was opened, an 

unfiltered sample of the water was poured immediately into a sample container and was sent to the 

NWQL for DOC analysis to verify that the source 

water used to prepare the equipment blanks was 

organic free. These two samples are referred to as 

source-solution blanks (Francy and others, 1998).

More stringent QA/QC procedures were applied 

to bacteria. For bacteria samples, the sterility of the 

buffer water and the sterilization techniques for the 

membrane-filtration equipment were tested by processing an equipment blank before each water sample 

was filtered.

Additional QA/QC methods to ensure sample 

integrity and final quality of data for VOC analyses 

were used as detailed by Parnell (1995). Each day 

before sample analysis, an instrument blank and 

syringe blank were run, followed by a calibration run. 

The instrument blank checked for a flat baseline signifying that no VOCs remained in the internal column of 

the gas chromatograph. The syringe blank ensured that 

the syringe used to deliver the samples to the gas chromatograph was free of VOCs and was also used to 

identify the resultant air peak on the chromatogram. At 

the end of the day, another instrument blank was run. 

To assess recovery bias of VOCs and variability in 

relation to different ground-water matrices, one water 

sample from the glacial deposits and one sample from 

the Cuyahoga Group was spiked in the USGS Columbus, Ohio, laboratory with known concentrations of 

the VOCs of interest and was analyzed 24 hours later 

to simulate field holding times. To assess loss or degradation of VOCs during sample collection and shipping, one spike was prepared per week of field work 

from organic-free water fortified with known concentrations of the VOCs of interest, was retained with the 

samples until the time of shipment, and then submitted 

to the Columbus, Ohio, laboratory. To identify contamination from migration of VOCs into the samples 

from the air, a trip blank of organic-free water was put 

in the same type of vial used for the environmental 

samples and kept with the VOC sample vials before 

and after sample collection. One trip blank was 

included in each shipment of VOC samples to the laboratory. At one sampling site (GE-77) where the faucet 

was in the garage and the air smelled of oil and paint, 
58 Ground-Water Quality in Geauga County, Ohio

an ambient air blank was collected to determine potential contamination of the environmental sample from 

conditions in the sampling environment (Francy and 

others, 1998). The ambient air blank was prepared at 

the sample-collection site by pouring organic-free 

water into a VOC vial and sending it to the laboratory 

in Columbus for analysis.

Quality-control data are listed in table A1. Out 

of a total of 83 comparisons of duplicate analyses, 71 

had a relative percent difference that was less than 5 

percent. Only 11 comparisons had relative percent differences that were greater than 5 percent; these are 

shown in bold type in table A1. The ratios computed 

with these problem values would still be reliable 

enough to determine water types and would not alter 

the determination of whether a constituent exceeded 

water-quality standards. The variability in NO3 concentrations in sample GE-349A is not enough to affect 

the classification as to whether the nitrate detected 

reflects anthropogenic influence or is indicative of 

background concentrations. Chloride-to-bromide 

ratios determined using duplicate values with a relative percent difference greater than 5 percent still plot 

very near the original points on the Cl:Br diagram and 

would not affect interpretations of the source of salinization in these samples.

Blank values were compared to all values for 

each constituent shown in table 5. In most cases, concentrations detected in the blanks are much less than 

concentrations in the environmental samples, often by 

2 or more orders of magnitude. In no case is the concentration value in the blank large enough to substantially affect the concentration of the constituent in the 

environmental sample.

Quality-control data for VOCs are not shown in 

table A1 because no VOCs were detected in any environmental sample or duplicate sample. Similarly, the 

instrument, syringe, field, trip, and ambient air blanks 

all contained no detectable VOCs. Calibration runs 

showed that the gas chromatograph was working properly, and spikes compared well with the calibration 

run, showing little if any qualitative loss or degradation of VOCs during sample collection and shipping. 

Matrix spikes also compared qualitatively well with 

the calibration run, indicating no recovery bias of 

VOCs and variability in relation to different groundwater matrices.

No bacteria were detected in any of the equipment blanks, an indication that equipment, supplies, 

and ambient environmental conditions did not bias the 

bacteria analyses in any way. Colonies that fluoresced 

but were small and green were not counted.

Table A1. Chemical characteristics of selected quality-control samples collected in Geauga County, 

Ohio, June and July 1999

[Well locations are shown in figure 1; Abbreviations: <, less than; col/100 mL, colonies per 100 milliliters; mg/L, milligrams per liter; 

μg/L, micrograms per liter; TU, tritium units; one TU = 3.24 picocuries per liter; --, not analyzed; boldface type indicates relative 

differences of 5 percent or greater]

Station name Date

pH,

water, 

whole, lab 

(standard 

units)

Coliform,

 total, water ,

unfiltered

(col/100 mL)

E. coli, water, 

unfiltered

(col/100 mL)

Calcium, 

dissolved 

(mg/L as Ca)

Magnesium,

dissolved 

(mg/L as Mg)

Sodium, 

dissolved

(mg/L as Na)

GE-119 6-17-1999 6.3 <1 <1 0.06 0.03 99

GE-119 DUP 6-17-1999 6.3 <1 <1 .06 .03 100

GE-165 6-8-1999 7.5 <1 <1 63 13 9

GE-165 DUP 6-8-1999 7.5 <1 <1 62 13 8.9

GE-349A 7-1-1999 6.6 1 <1 26 5.8 24

GE-349A DUP 7-1-1999 7.0 1 <1 27 6 25

GE-119 BLANK 6-17-1999 7.3 <1 <1 .01a <.004 .05a

GE-165 BLANK 6-8-1999 8.1 <1 <1 .09 .004 .03a

GE-349A BLANK 7-1-1999 7.1 <1 <1 .02 .002a <.06

GE-165 SOURCE 6-8-1999 -- -- -- -- -- --

GE-349A SOURCE 7-1-1999 -- -- -- -- -- --
Appendix A: Quality Assurance/Quality Control 59

Table A1. Chemical characteristics of selected quality-control samples collected in 

Geauga County, Ohio, June and July 1999—Continued

[Well locations are shown in figure 1; Abbreviations: <, less than; col/100 mL, colonies per 100 milliliters; mg/L, milligrams per liter; 

ug/L, micrograms per liter; TU, tritium units; one TU = 3.24 picocuries per liter; --, not analyzed; boldface type indicates relative 

differences of 5 percent or greater]

Station name

Potassium,

dissolved

(mg/L as K)

Bicarbonate,

water, field

(mg/L as 

HCO3)

Carbonate, 

water, field

(mg/L as 

CO3)

Alkalinity,

water, field

(mg/L as 

CaCO3)

Sulfide,

total 

(mg/L as S)

Sulfate,

dissolved

(mg/L as 

SO4)

Chloride,

dissolved

(mg/L as Cl)

GE-119 0.2 130 0 110 0.02 70 21

GE-119 DUP .2 130 0 110 -- 70 23

GE-165 .9 200 0 170 .01 37 20

GE-165 DUP .9 200 0 170 .01 37 20

GE-349A 1.8 42 0 34 <.01 35 43

GE-349A DUP 1.8 40 0 30 <.01 35 43

GE-119 BLANK <.1 -- -- -- -- <.1 <.1

GE-165 BLANK <.1 -- -- -- -- <.1 <.1

GE-349A BLANK <.1 -- -- -- -- <.1 <.1

GE-165 SOURCE -- -- -- -- -- -- --

GE-349A SOURCE -- -- -- -- -- -- --

Station name

Bromide,

dissolved

(mg/L as Br)

Silica,

dissolved

(mg/L as 

SiO2)

Solids,

residue

at 180

degrees

Celsius,

dissolved

(mg/L)

Nitrogen,

nitrate,

dissolved

(mg/L as N)

Nitrogen,

nitrite,

dissolved

(mg/L as N)

Nitrogen,

ammonia,

dissolved

(mg/L as N)

Nitrogen,

ammonia +

organic,

dissolved

(mg/L as N)

Phosphorus,

dissolved

(mg/L as P)

GE-119 0.02 11 283 <0.18 <0.02 <0.03 <0.005 <0.02

GE-119 DUP .03 10 287 <.18 <.02 <.03 <.005 <.02

GE-165 .21 10 272 <.18 <.02 .04 <.005 <.02

GE-165 DUP .21 10 282 <.18 <.02 .04 <.005 <.02

GE-349A .05 8.0 231 2.2 <.02 <.03 <.005 <.02

GE-349A DUP .06 8.2 223 2.4 <.02 <.03 <.005 <.02

GE-119 BLANK <.01 <.05 <10 <.18 <.02 <.03 <.005 <.02

GE-165 BLANK <.01 <.05 <10 <.18 <.02 .03 <.005 <.02

GE-349A BLANK <.01 .05 <10 <.18 <.02 .03 .034 <.02

GE-165 SOURCE -- -- -- -- -- -- -- --

GE-349A SOURCE -- -- -- -- -- -- -- --
60 Ground-Water Quality in Geauga County, Ohio

Table A1. Chemical characteristics of selected quality-control samples collected in Geauga County, Ohio, June 

and July, 1999— Continued

[Well locations are shown in figure 1; Abbreviations: <, less than; col/100 mL, colonies per 100 milliliters; mg/L, milligrams per liter; 

ug/L, micrograms per liter; TU, tritium units; one TU = 3.24 picocuries per liter; --, not analyzed; boldface type indicates relative 

differences of 5 percent or greater]

Station name

Phosphorus,

ortho, 

dissolved

(mg/L as P)

Boron,

dissolved

(μg/L as B)

Iron,

dissolved

(μg/L as Fe)

Manganese,

dissolved

(μg/L as Mn)

Strontium,

dissolved

(μg/L as Sr)

Carbon,

organic,

dissolved

(mg/L as C)

Tritium,

total 

(TU)

GE-119 <0.01 25.0 18 6 <1 0.9 --

GE-119 DUP <.01 22.5 21 6 <1 .8 --

GE-165 <.01 18.3 1900 180 84 .3 --

GE-165 DUP <.01 19.0 1800 180 83 .3 --

GE-349A <.01 56.5 15 <3 88 .8 14.6

GE-349A DUP <.01 59.8 19 2a 88 .8 14.6

GE-119 BLANK .01 8.5a <10 <3 <1 <.1 --

GE-165 BLANK <.01 10.4a <10 <3 <1 <.1 --

GE-349A BLANK <.01 10.8a

a

Estimated values are lower than the lowest calibration standard but higher than the detection limit of the machine.

6a <3 <1 <.1 --

GE-165 SOURCE -- -- -- -- -- <.1 --

GE-349A SOURCE -- -- -- -- -- .2 --