U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2012–3118

November 2012

Science to Support the Understanding 

of Ohio’s Water Resources 

Figure 1. Ohio basins and major watersheds. 

Introduction

Ohio’s water resources support a 

complex web of human activities and 

nature—clean and abundant water is 

needed for drinking, recreation, farming, and industry, as well as for fish and 

wildlife needs. The distribution of rainfall 

can cause floods and droughts, which 

affects streamflow, groundwater, water 

availability, water quality, recreation, and 

aquatic habitats. Ohio is bordered by the 

Ohio River and Lake Erie and has over 

44,000 miles of streams and more than 

60,000 lakes and ponds (State of Ohio, 

1994). Nearly all the rural population 

obtain drinking water from groundwater 

sources. 

The U.S. Geological Survey (USGS) 

works in cooperation with local, State, 

and other Federal agencies, as well as 

universities, to furnish decisionmakers, 

policymakers, USGS scientists, and the 

general public with reliable scientific 

information and tools to assist them in 

management, stewardship, and use of 

Ohio’s natural resources. The diversity of 

scientific expertise among USGS personnel enables them to carry out large- and 

small-scale multidisciplinary studies. The 

USGS is unique among government organizations because it has neither regulatory 

nor developmental authority—its sole 

product is reliable, impartial, credible, 

relevant, and timely scientific information, equally accessible and available to 

everyone. The USGS Ohio Water Science 

Center provides reliable hydrologic and 

water-related ecological information to 

aid in the understanding of use and management of the Nation’s water resources, 

in general, and Ohio’s water resources, 

in particular. This fact sheet provides an 

overview of current (2012) or recently 

completed USGS studies and data activities pertaining to water resources in Ohio. 

More information regarding projects of 

the USGS Ohio Water Science Center is 

available at http://oh.water.usgs.gov/. 

Sandusky River

Mahoning River

Ohio River

Rocky River

Black River

Scioto River

Cuyahoga

Maumee River

Huron River

Muskingum River

Hocking River

Little Miami River

Great Miami River

GrandRiver

Chagrin R.

Portage River

Grand

Lake

St Marys

LAKE ERIE

OHIO

INDIANA

KENTUCKY

MICHIGAN

CANADA

UNITED STATES

WEST VIRGINIA

PENNSYLVANIA

KNOX

STARK

DARKE

LICKING

SCIOTO

ADAMS

WAYNE

SENECA

HURON

LOGAN

GALLIA

ROSS

PIKE

WOOD

LORAIN

MEIGS

PERRY

UNION

ALLEN

ATHENS

HENRY

BROWN

CLARK

BUTLER

MIAMI

NOBLE

HARDIN

ASHTABULA

ERIE

TRUMBULL

MERCER

PREBLE

PORTAGE

BELMONT

FRANKLIN

PUTNAM

WARREN

MORGAN

COSHOCTON

WASHINGTON

CARROLL

JACKSON

ASHLAND

MORROW

DEFIANCE CUYAHOGA

DELAWARE

CLERMONT

WILLIAMS

LAWRENCE

PAULDING

AUGLAIZE

TUSCARAWAS

WYANDOT

HARRISON

VAN WERT

COLUMBIANA

HAMILTON

SANDUSKY

MAHONING

JEFFERSON

CRAWFORD

CHAMPAIGN

HANCOCK

SHELBY

FULTON

VINTON

LUCAS

HIGHLAND

GREENE FAIRFIELD

MUSKINGUM

MONROE

MEDINA

HOLMES

FAYETTE

GUERNSEY

SUMMIT

RICHLAND

GEAUGA

PICKAWAY

MARION

MADISON

LAKE

CLINTON

HOCKING

MONTGOMERY

OTTAWA

EXPLANATION

Major watershed

Watershed boundary

Ohio River Basin

Lake Erie Basin

0 30 60 MILES

0 30 60 KILOMETERS

Base modified from U.S. Geological Survey 

1:24,000 scale digital data.

Universal Transverse Mercator Zone 17 

North American Datum of 1983

40°0'N

84°0'W

82°0'W

42°0'N
Streamflow Data Available Online

The USGS in Ohio—in cooperation with local, State, and Federal partners—operates about 230 streamgage stations, with about 160 gages recording streamflow. There 

are about 7,400 streamgages nationwide; many of these gages provide real-time data in 

15-minute increments, which typically are transmitted to the Web every hour via satellite. 

These streamgages provide streamflow information for a wide variety of uses including 

flood prediction, water management and allocation, engineering design, research, operation of locks and dams, and recreational safety and enjoyment. In addition to these data, 

field-measurement data, streamflow statistics, and annual peak streamflows from each 

station are available on the Web through the National Water Information System (NWIS). 

http://waterdata.usgs.gov/oh/nwis/rt

For more information, contact James Mangus, jpmangus@usgs.gov.

Groundwater Data Available Online

State and local agencies in Ohio are responsible for collecting, researching, interpreting, and disseminating groundwater data to characterize the groundwater resources of the 

State. To address these needs, the Ohio Department of Natural Resources (ODNR) and the 

Miami Conservancy District (MCD) monitor groundwater levels at more than 140 wells 

throughout Ohio. Personnel from the USGS Ohio Water Science Center and ODNR compile and publish water levels on the Groundwater Watch and NWIS web sites.

http://groundwaterwatch.usgs.gov/StateMaps/OH.html

For more information, contact Ralph Haefner, rhaefner@usgs.gov.

Water-Quality Monitor Network in Ohio

The USGS operates a network of near real-time water-quality monitoring stations 

that provides temperature, specific conductance, pH, dissolved oxygen, and turbidity of 

surface water. These data are needed for decisionmaking regarding drinking water, water 

treatment, regulatory programs, recreation, healthy ecosystems, and public safety. Data 

are stored in the NWIS.

http://waterwatch.usgs.gov/wqwatch/

http://waterdata.usgs.gov/oh/nwis/current/?type=quality&group_key=NONE

For more information, contact Kimberly Shaffer, kshaffer@usgs.gov. 

Nowcast—Water-Quality Conditions at Beaches and a Recreational River

Local agencies monitor the water to measure the concentration of Escherichia coli

(E. coli)—an indicator bacterium found in sewage and other animal wastes—to determine 

if it is safe to swim in a lake or canoe in a river. Conventional methods can take 18 to 24 

hours to get results. To improve the timeliness and accuracy of recreational water-quality 

assessments, quick measurements, such as rainfall or water clarity, can be used to estimate 

the probability that E. coli exceeds safe levels. This “nowcast” system provides nearreal-time beach advisories to the public on the basis of predictive models. The USGS, in 

cooperation with many local and State agencies, is working to improve nowcast systems 

currently (2012) in operation and expand the use of operational predictive models and 

nowcast systems at more than 50 beaches throughout the Great Lakes and at inland lakes 

in Ohio. 

http://www.ohionowcast.info/index.asp

For more information, contact Donna Francy, dsfrancy@usgs.gov. 

Ohio Water-Use Program

Every five years since 1950, water-use data have been compiled and disseminated 

in Ohio as part of the USGS National Water-Use Information program. Current water-use 

categories include public supply, domestic, irrigation, livestock, aquaculture, industry, 

mining, and thermoelectric power. Water-use data are available by county and 8-digit 

Hydrologic Unit Codes.

http://oh.water.usgs.gov/water_use.html

For more information, contact Kimberly Shaffer, kshaffer@usgs.gov.

USGS Water-Resource Activities in Ohio Data
Surface Water USGS Water-Resource Activities in Ohio

Assessing Potential Climate-Change Effects in the Upper Scioto River 

Basin 

The central Ohio region is projected to grow by 450,000 people between 2005 and 

2030 (Ohio Department of Development, 2003). The USGS is developing a watershed 

rainfall-runoff model to help water managers and planners assess whether existing and 

planned water-supply systems will be adequate to meet the region’s future demand for 

water. This model will be used to estimate potential hydrologic effects of climate-change 

outcomes predicted by several climate-change models and will be instrumental for evaluating potential, future alternative water-management practices.

For more information, contact Chad Ostheimer, ostheime@usgs.gov.

Low-Flow Streamgage Network in Ohio

Data on low-flow characteristics are used by water-resource managers for a variety of 

purposes, including water-supply planning, making decisions about wastewater-discharge 

and water-withdrawal permits, and evaluating in-stream flow requirements. The objective 

of this study is to collect low-flow data at locations throughout Ohio to expand the base 

of available information. The Ohio low-flow network consists of both continuous-record 

streamflow sites and sites where streamflow is only measured during low-flow periods.

http://oh.water.usgs.gov/low-flow_network.html 

For more information, contact Dave Straub, destraub@usgs.gov. 

Crest-Stage Streamgage Network in Ohio

Historically, small streams with drainage areas less than 100 square miles have not 

been adequately represented in regional peak- (high) flow analysis. To help fill this data 

gap, crest-stage gages were installed during 2001 at 18 sites throughout Ohio to augment 

the peak-flow record for small-drainage-area streams. After enough peak-flow measurements have been collected at these sites, the statewide flood-frequency analysis will be 

updated to improve the estimation of peak flows.

http://oh.water.usgs.gov/crest-stage.html

For more information, contact Andrew Ebner, aebner@usgs.gov.

StreamStats

Ohio StreamStats is a Web-based Geographic Information System (GIS) application that allows users to easily obtain a variety of low flow and peak flow statistics; 

daily, monthly, and annual streamflow statistics; basin characteristics; and other information for ungaged stream sites in Ohio. Published statistics for gaged sites in the NWIS 

also are provided through the StreamStats map application. The StreamStats interface 

includes an assortment of analytical tools that are useful for water-resources planning and 

management.

http://water.usgs.gov/osw/streamstats/ohio.html

For more information, contact Greg Koltun, gfkoltun@usgs.gov.

Flood-Studies and Flood-Warning Systems Program

This program employs hydrologic and hydraulic analyses to determine water-surface 

elevations associated with specific flood magnitudes at several points along a stream 

channel. The water-surface elevation data are used together with land-surface elevation 

data to determine and map the corresponding spatial extent of flood inundation. In some 

cases, libraries of flood-inundation maps are prepared for stream channels near USGS 

gaging stations at which the National Weather Service (NWS) forecasts flood levels. In 

those cases, the NWS forecasts can be used in advance via map-based Web applications 

(for example, see http://wim.usgs.gov/FIMI) to determine areas that are likely to flood at 

the forecasted levels. These studies, and information developed, serve as a foundation for 

making science-based decisions to better manage flood risk and efforts to mitigate flood 

impacts. 

http://water.usgs.gov/osw/flood_inundation/ 

For more information, contact Dave Straub, destraub@usgs.gov. 

(Photograph by Mary Terry, courtesy of Findlay 

Engineer’s Office, Findlay, Ohio.)
USGS Water-Resource Activities in Ohio Water Quality

Microbial Source Tracking

The City of Columbus is in the process of updating its wastewater infrastructure 

and treatment-plant operations to reduce the occurrence of combined sewer overflows to 

waterways such as the Olentangy and Scioto Rivers. The USGS is working with the City 

to analyze river-water samples for microbial source tracking (MST) markers to help characterize the impact of various sources of fecal contamination. The USGS also is conducting MST analysis on a subset of river sites during wet and dry weather conditions. 

http://oh.water.usgs.gov/micro_sourcetracking.htm

For more information, contact Chris Kephart, ckephart@usgs.gov.

Testing Rapid Detection Methods for Drinking Water and Recreational 

Waters

Rapid water-quality tests for microorganisms are needed to quickly ensure that water 

is safe for consumption or recreation. The USGS is developing and testing rapid methods 

for the detection of the viable (living) microorganisms that are potential biothreat agents 

in large-volume drinking-water samples—Bacillus anthracis (anthrax), Francisella 

tularensis (tularemia), and Yersinia pestis (plagues). Results from viability methods will 

be compared to culture and other method results. The USGS also has been working on 

optimizing and testing methods that will provide E. coli and enterococci results in 2 hours 

rather than the conventional 18–24 hours for recreational waters. The Ohio Water Microbiology Lab continues to optimize the methods, which are now being tested by numerous 

agencies.

http://oh.water.usgs.gov/micro_rapiddetection.htm

For more information, contact Rebecca Bushon, rnbushon@usgs.gov.

Modeling Aquatic Species Distributions Based on Physical Habitat and 

Climate Change

Gap analysis is a coarse-scale assessment of aquatic biodiversity and conservation, 

the results of which can be used to guide biological field studies and monitoring programs. Potential species distribution models were developed for 130 fish, 70 bivalve, and 

17 native crayfish species based on a physical habitat-based classification of the perennial 

streams in Ohio. 

A more recent study is integrating fish-habitat classifications and associated fishcommunity data with downscaled (regional) climate predictions under different change 

scenarios to identify vulnerabilities of river systems and to project likely changes to 

important fish species.

http://oh.water.usgs.gov/ohgap.htm

For more information, contact Alex Covert, sacovert@usgs.gov.

Cyanobacteria and Toxins—Grand Lake St. Marys

In recent years, measurements of microcystin (a toxin) associated with harmful algal 

blooms caused by cyanobacteria in Grand Lake St. Marys have exceeded recreationalwater guidelines, and the Ohio Environmental Protection Agency has issued water-quality 

advisories for the lake. The USGS, in cooperation with the Ohio Water Development 

Authority, City of Celina, and Grand Lake St. Marys State Park, is studying the distribution and timing of the occurrence of cyanobacteria and microcystin production and 

documenting the distributions of water-quality conditions and cyanobacteria, microcystin, 

and nutrient concentrations. Continuous water-quality conditions are being measured at 

two depths at one location, and water samples are being collected five times a year at six 

locations. 

http://waterdata.usgs.gov/oh/nwis/

uv/?site_no=403139084293900&PARAmeter_cd=00010,00095,00300,00400

For more information, contact Denise Dumouchelle, ddumouch@usgs.gov. 

(Photograph by Brian Caskey, USGS.)
Groundwater USGS Water-Resource Activities in Ohio

Long-Term Water-Level Monitoring Network, Geauga County, Ohio

Residents of Geauga County rely almost exclusively on groundwater as their source 

of drinking water. County planners are concerned that steady population growth, in combination with extensive groundwater use by county residents, will result in water being 

withdrawn faster than it is recharged. This study involves monitoring groundwater levels 

in 31 wells across the county that are in four widely used aquifers. Knowledge of the magnitude and locations of groundwater declines in the county are needed to assist in planning 

for continued growth and conservation of groundwater resources. 

Another project, which monitors water levels from a network in the vicinity of South 

Russell Village, Geauga County, is used to evaluate whether variations in groundwater 

levels are caused by annual variations in precipitation or residential and commercial 

development.

http://groundwaterwatch.usgs.gov/countymaps/OH_055.html

For more information, contact Martha Jagucki, mjagucki@usgs.gov.

Hydraulic Characteristics of Low-Impact Development Practices in 

Northeastern Ohio

Low-impact development (LID) is an approach to managing storm water as near to 

its source as possible; this is accomplished by minimizing impervious surfaces and promoting more natural infiltration and evapotranspiration than is typically associated with 

developed areas. Two newly constructed LID sites in northeastern Ohio are being studied 

to document their hydraulic characteristics. One of the sites is a roadside best-management practice that replaced existing roadside ditches with a bioswale/rain garden, and the 

other site makes use of pervious pavers and a rain garden to receive runoff from the roof 

of a nearby commercial building.

http://pubs.usgs.gov/sir/2011/5165/

For more information, contact Robert Darner, radarner@usgs.gov.

Hydrologic Influences of Storm-Water Best-Management Practices at the 

Cincinnati Zoo

The Metropolitan Sewer District of Greater Cincinnati and the Cincinnati Zoo and 

Botanical Garden have undertaken a project to remove a parking lot and replace it with 

animal exhibits that incorporate best-management practices to reduce storm-water runoff. 

The USGS is collecting hydrologic data to help determine the influences of these practices 

on local groundwater. Monitoring currently (2012) includes measurement of water levels 

and quality in four wells and data collection at a weather station.

http://groundwaterwatch.usgs.gov/StateMaps/OH.html

For more information, contact Robert Darner, radarner@usgs.gov.

(Photograph by personnel of Cawrse and 

Associates, Inc., Chagrin Falls, Ohio.)

Arsenic in Groundwater of Licking County

Arsenic is odorless and tasteless and can enter drinking-water supplies from natural 

deposits in rock and soil. In some parts of Ohio, arsenic concentrations in groundwater 

can exceed the arsenic health standard of 10 parts per billion that the U.S. Environmental 

Protection Agency has set to protect consumers from the effects of long-term, chronic 

exposure to arsenic (U.S. Environmental Protection Agency, 2012). The USGS is investigating arsenic concentrations in water from domestic wells in Licking County as part of a 

broader effort to understand which parts of the groundwater system are most vulnerable to 

contamination from naturally occurring arsenic. 

http://arsenicinohiogroundwater.info/

For more information, contact Mary Ann Thomas, mathomas@usgs.gov.
References Cited 

Ohio Department of Development, 2003, 

Office of Policy Research and Strategic Planning, Population projections 

for Ohio and counties by age and sex, 

2000 to 2030, accessed July 23, 2012, 

at http://www.development.ohio.gov/

research/Reports_in_population_and_

housing-Population_Projections.htm.

State of Ohio, 1994, Ohio’s water Ohio’s 

future—1994 Final report: Governor’s blue ribbon task force on water 

resources planning and development, 

31 p. Accessed July 23, 2012, at www.

dnr.state.oh.us/Portals/7/pubs/reports/

Ohiowaterfuture.pdf.

U.S. Environmental Protection Agency, 

2012, Arsenic in drinking water, 

accessed June 15, 2012, at http://water.

epa.gov/lawsregs/rulesregs/sdwa/

arsenic/index.cfm. 

—compiled by Kimberly Shaffer, Stephanie Kula, Phil Bambach, and Donna Runkle

This fact sheet is available online at http://pubs.usgs.gov.

Figures, illustrations, text, and pictures were provided by U.S. Geological Survey personnel.

For additional information, contact

Director (dc_oh@usgs.gov) 

U.S. Geological Survey 

Ohio Water Science Center

6480 Doubletree Avenue

Columbus, OH 43229–1111

Phone: (614) 430-7700 Fax: (614) 430-7777

Publishing support provided by Bonnie J. Stich,

Columbus Publishing Service Center

http://oh.water.usgs.gov/

National Water-Quality Assessment (NAWQA) Program 

The Lake Erie and Lake Saint Clair (LERI) Basins in Indiana, Michigan, New York, 

Ohio, and Pennsylvania and the White, Great, and Little Miami River (WHMI) Basins in 

Indiana and Ohio comprise 2 of more than 50 study units that are part of the USGS 

NAWQA program. The long-term goals of the NAWQA program are to describe waterquality status and trends in a large representative part of the Nation’s surface-water and 

groundwater resources and to provide a sound, scientific understanding of the primary 

factors affecting the quality of these resources.

http://water.usgs.gov/nawqa/

For more information, contact Allison Kunze, aekunze@usgs.gov.

Ecology, Streams, and Groundwater—Lake Erie and Lake Saint Clair 

Basins

The LERI NAWQA ecology study includes the collection of habitat, fish, algae, and 

macroinvertebrate-community data from selected streams in the LERI study unit. Data 

have been collected since 1994 and are stored in an ecological database (BioData).

https://aquatic.biodata.usgs.gov/ 

For more information, contact Stephanie Janosy, sjanosy@usgs.gov.

The LERI NAWQA surface-water status and trends study includes the collection of 

sediment and water-quality samples from the Maumee and Auglaize Rivers in Ohio. Since 

1994, samples have been collected on these rivers for the NAWQA program.

For more information, contact Dennis Finnegan, dpfinneg@usgs.gov.

The LERI NAWQA groundwater study includes collecting groundwater-quality 

samples and measuring water levels in a glacial aquifer in three well networks made up of 

monitoring wells (in urban areas and areas relatively undisturbed by human activities) and 

domestic wells (in urban and agricultural areas).

For more information, contact Donna Runkle, dlrunkle@usgs.gov.

Groundwater—White, Great, and Little Miami River Basins

The groundwater study in the White, Great, and Little Miami River (WHMI) 

Basins in Indiana and Ohio includes the collection of groundwater-quality samples and 

measurement of groundwater levels in three well networks in the Glacial Aquifer System.

For more information, contact Mary Ann Thomas, mathomas@usgs.gov. 

USGS Water-Resource Activities in Ohio NAWQA

Indiana Ohio

WHMI

Other USGS Resources

Climate and Land-Use Change 

http://www.usgs.gov/climate_landuse/

Core Science Systems (Mapping)

http://www.usgs.gov/core_science_systems/

Ecosystems 

http://www.usgs.gov/ecosystems/

Energy and Minerals, and Environmental 

Health 

http://www.usgs.gov/resources_envirohealth/

Natural Hazards 

http://www.usgs.gov/natural_hazards/