U.S. Department of the Interior

U.S. Geological Survey

USGS Fact Sheet 014-99

December 1999

Illinois

Urbanization and Flooding

Urbanization of drainage areas often

leads to unanticipated high peak

streamflows and increased frequency

of flooding within or downstream

from these areas. The evaluation of

the effect of urbanization on flooding

requires the collection of consistent,

high-quality streamflow and rainfall

data, which can be used to develop

computer-based models that simulate

runoff processes in watersheds.

Simulation results are used for

planning, designing, and managing

roads, bridges, culverts, dams, and

flood-control reservoirs.

The U.S. Geological Survey (USGS)

collects continuous streamflow and

rainfall data in the suburban counties

of metropolitan Chicago that are

rapidly developing. These data are

used to calibrate models of watershed

runoff response to rainfall, which

then are used to simulate runoff and

flooding associated with a variety of

land-use conditions and storms. A

real-time rainfall gage network with

radio telemetry has been installed in

Du Page County. The data provided

by this network entered into a linked

system of model data bases, and

watershed and streamflow models, to

produce information that can be used

to optimize reservoir operations to

reduce the severity of flooding in the

county. The Du Page County Department of Environmental Concerns, the

Lake County Stormwater Management Commission, and the Illinois

Department of Natural ResourcesOffice of Water Resources cooperate

with the USGS in these activities.

Managing Invasive Aquatic

Species

USGS scientists are working with the

State and other Federal agencies to

control the spread of several nonnative aquatic animals and plants that

are affecting the ecology and the

economy of the upper Midwest.

Targeted species include the zebra

mussel (fig. 1), a fast-growing

invader that forms large colonies on

hard surfaces. The mussel, a Eurasian

species likely introduced to the Great

Lakes through the release of ballast

water from seagoing freighters,

successfully competes with native

aquatic species for space, food, and

oxygen. Many industries and municipalities must perform costly maintenance to remove mussel growth from

water-intake structures. Other problem species include the round goby, a

recently introduced fish that may

follow the path of the zebra mussel

from the Great Lakes into the interior

of North America, and the purple

Loosestrife, an aggressive plant

invader of wetland areas. Researchers

are seeking to understand the biology

and halt the spread of the invasive

species, which threaten the integrity

of native ecosystems. Scientists also

are implementing a multifaceted

program, involving electrified weirs

and delayed-release fish poisons,

aimed at restricting further range

expansion of these aquatic nuisance

species.

Diversion of Water from Lake

Michigan

Since 1900, with the construction of

the Chicago Sanitary and Ship Canal

(CSSC; includes the Chicago River,

Calumet River, and associated

waterways), water has been diverted

from Lake Michigan for domestic

water supply and as direct diversion

into the canal to the Des Plaines

River and then to the Illinois River

(fig. 2). Historically, the direct

diversion by the Metropolitan Water

Reclamation District of Greater

Chicago (MWRDGC) was intended

to protect the drinking-water supply

from Lake Michigan by carrying

treated sanitary wastewater away

from the lake and to provide for

navigation by allowing barge traffic

on the Illinois River between the

Mississippi River and Chicago.

Currently, the direct diversion is used

for water-quality improvement and

navigation in the CSSC. The most

recent U.S. Supreme Court decision

(1967 and modified December 1,

1980) that regulates the diversion of

water from Lake Michigan limits

diversion by the State to a 40-year

average of 3,200 cubic feet per

second. The U.S. Army Corps of

Figure 1. Zebra mussels threaten the

ecosystem by killing native mussels

and by clogging water-intake

structures.
science for a changing world

Engineers (USACE) is responsible

for computing the diversion by the

State of Illinois, and the State is

responsible for allocating the diverted

water.

The USACE has determined that

diversion exceeded the 3,200-cubicfeet per-second limit from the 1983 to

1993 water years (the water year is

from October 1 through September

30). The USGS is applying acoustic

Doppler current profilers and acoustic

velocity meters (AVM’s), to measure

flows in the Chicago River at Chicago, Calumet River at O’Brien Lock

and Dam, and the CSSC at

Romeoville, and leakage through the

lakefront diversion-control structures.

Measurements made by the USGS

indicate that actual leakage through

the lakefront diversion-control

structures is much greater than

previous estimates, and support the

need for structural improvements to

the control structures by the State and

USACE. The USGS is responsible for

the ongoing operation and maintenance of the AVM’s by agreement

with the USACE. The USGS is

cooperating with the USACE, the

Illinois Department of Natural

Resources, and the MWRDGC to

refine and improve the Lake Michigan diversion accounting procedures.

Glacial Geologic Mapping In

Illinois

A 1998 USGS map portrays the

thickness and character of glacial

deposits in Illinois (fig. 3) and

adjacent States. The map complements other State maps of the glacial

history and the buried-bedrock

surface, all of which are used to

assess ground water in glacial

aquifers; susceptibility of aquifers to

contamination; extent of sand and

gravel for construction aggregate;

and potential for earthquake, flood,

radon, and coastal-erosion hazards;

and for environmental and ecosystem

studies. The USGS, the Illinois State

Geological Survey (ISGS), and

adjacent States are developing the

Central Great Lakes Mapping

Coalition, which plans to map

priority glacial deposits at 1:24,000

scale in three dimensions using

modern geophysical and drilling

methods, geologic sedimentation

models, and computer-assisted

analyses. The multiagency mapping

program will characterize the water

and aggregate resources for surface

and subsurface units, their geochemical composition, and their likely

roles in natural hazards and contamination potential. The Coalition seeks

to develop ways to teach local landuse managers and planners how to

use the new, detailed data and software tools to make informed decisions for sustainable growth in the

region.

Water Quality of the Illinois River

Basin

Protecting the quality of the Nation’s

water resources is a priority concern.

To address this concern, scientists in

the USGS National Water Quality

Assessment (NAWQA) Program are

collecting water-quality and biological data in the lower and upper

Figure 3. Surficial glacial deposits in

Illinois: glacial till deposits in green;

sand-and-gravel deposits in yelloworange; and silt and clay deposits in

blue. Darker shades indicate thicker

deposits and can be used to trace

ancient buried valleys that are filled

with complex glacial deposits across

the central part of the State.

Unglaciated

Unglaciated

Figure 2. Waterways in the Chicago

area before and after the Lake

Michigan diversion.

Des Plaines River

Calumet Rivers

Chicago

Rivers

Des Plaines

Cal-Sag Channel

Calum et Rivers

River

Chicago

Rivers

La

ke Michigan

La

ke Michigan

CSSC

BEFORE DIVERSION

AFTER DIVERSION- Circa 1900 

Control structure 

0

0

5

5

10 Miles

10 Kilometers

0

0

5

5

10 Miles

10 Kilometers

Acoustic velocity meter 

Direction of Flow

EXPLANATION
Illinois

Lower

Illinois

River

Basin

Upper

Illinois

River

Basin

ILLINOIS

INDIANAMICHIGAN

WISCONSIN

Illinois River

Lake

Michigan

Figure 4. Illinois River Basin National

Water-Quality Assessment (NAWQA)

Program study units in Illinois,

Indiana, and Wisconsin.

Illinois River Basins (fig. 4). The

objectives of the Illinois River Basin

NAWQA study are to describe current

water quality and to track long-term

water-quality trends. Agrichemical

and urban-related contaminants are

sampled in water and sediments.

In surface-water samples from the

lower Illinois River Basin, nitrate and

many pesticides were detected—

commonly at levels of regulatory

concern—during the high-intensity

data collection that ended in 1998.

Ground water in the lower basin was

sampled primarily for analysis of

agrichemicals. Few or no pesticides

were detected in water from the wells

sampled, and water samples from

only a few shallow wells had nitrate

levels that exceeded drinking-water

standards. Arsenic and radon were

detected at levels of regulatory

concern in ground water in the lower

basin.

Intensive data collection will begin in

the upper Illinois River Basin in

1999. Although agrichemicals also

are a concern in the basin, a primary

study objective will be the collection

of samples in urbanized areas to

determine the effects of urbanization

on water quality and aquatic organisms. The NAWQA Program studies

in Illinois have established liaison

committees with representatives from

Federal, State, and local agencies to

help identify topics for study.

Coal Availability and

Recoverability

The availability of environmentally

acceptable and reliable energy

sources at reasonable prices is an

important issue for Federal, State, and

local planners. The USGS and 13

cooperating State geological surveys

have developed a systematic national

effort to collect, analyze, and depict

data that characterize the relation

between restrictions to mining and

the potential for development of coal

resources.

The ISGS began the first of 22

cooperative projects in the Illinois

Basin in 1992. Each 7.5-minute

quadrangle area selected is representative of the geologic, physiographic,

land-use, and mining conditions of its

surrounding area. State scientists

identify land-use, environmental,

technological, and geological constraints within each study area and,

using geographic information systems

modeling, apply these restrictions to

maps of coal bed and coal-zone

thickness, depth of burial, and minedout areas. The State, after consulting

with local mining experts, estimates

the unmined and unrestricted tonnage

of coal that remains in the ground and

is available for development. In the

18 completed studies, this amounts to

about 39 percent of the original coal.

ISGS scientists then transfer digital

files of the completed studies to the

USGS. USGS geologists and engineers model mine plans, estimate

future mining and washing losses,

and determine potential economically

recoverable coal in each study area.

The amount of unrestricted coal in the

Illinois Basin that can be extracted

and marketed at a profit, at current

costs, is expected to average about 8

percent of the original coal resource.

Under a parallel USGS–State cooperative project, the National Coal

Resource Assessment, the ISGS is

preparing basinwide maps, models,

and resource estimates for three

major coal beds—Springfield, Herrin,

and Danville. Applying knowledge

gained from the 18 completed studies,

the ISGS, in collaboration with the

Indiana Geological Survey, has begun

a basinwide assessment of the availability of the Springfield coal.

Biological Effects of PCB’s in the

Upper Mississippi River

USGS scientists, in partnership with

the U.S. Fish and Wildlife Service,

are evaluating the amount of polychlorinated biphenyls (PCB’s) in

wildlife along the upper Mississippi

River to determine if further management and mitigation are warranted.

Great strides have been made in

recent years to clean up and eliminate

PCB sources in the Quad Cities’

(Davenport and Bettendorf, Iowa; and

Rock Island and Moline, Ill. ) stretch

of the upper Mississippi River. These

chemicals commonly remain trapped

Figure 5. Tree swallows are being

studied to determine how PCB

contamination in the upper

Mississippi River affects wildlife.
Printed on recycled paper

USGS office locations USGS State Representative

The USGS has 81 

employees in Illinois

De Kalb

Mount

Vernon

Urbana

221 North Broadway Avenue

Urbana, IL 61801

(217) 344-0037, ext. 3003

FAX (217) 344-0082

USGS Home Page

http://www.usgs.gov

Reports and products

1-888-ASK-USGS

in fatty tissues, accumulating to toxic

levels in predatory animals. Tree

swallows, which feed on aquatic

insects that hatch from river water

and sediments, are being used as an

indicator of PCB contamination and

transfer up ecological food chains

(fig. 5).

Partnership for Statewide 1998–99

Aerial Photography Coverage

The USGS, in cooperation with the

Illinois Department of Transportation,

is acquiring photographs of the State

in 1998–99 through the National

Aerial Photography Program

(NAPP). These black-and-white

photographs are intended to be used

for planning transportation and

construction, studying land-use

changes, and planning new subdivisions. Additionally, the NAPP

photographs will be the basis for

statewide digital orthophoto quadrangle (DOQ) coverage for Illinois. A

DOQ is a computer-generated image

of an aerial photograph and has the

geometric qualities of a map.

The Illinois Department of Transportation intends to distribute NAPP

photographs in Illinois. These photographs have many applications,

including use in making decisions

related to the environment, natural

resources, natural disasters and

hazards, property assessment, agriculture, and recreation.

Partnership to Update

Topographic Maps in Illinois

Government agencies, the private

sector, academia, and citizens rely on

USGS 7.5-minute topographic maps

in their work, as well as in recreational activities. In an ongoing

partnership agreement with the

USGS, the Illinois Department of

Transportation and the Illinois

Department of Natural Resources

annually contribute matching funds

toward updating printed USGS

topographic maps, which yields many

benefits to the people of Illinois.

Water-Information Collection and

Sediment Monitoring

Water-quality and -quantity data are

used for monitoring, planning,

designing, hazard warnings, operating, and managing water-related

activities, such as water supply,

hydroelectric power generation, flood

control, irrigation, bridge and culvert

design, wildlife management, pollution abatement, flood-plain management, and water-resources development. The USGS, in cooperation with

more than 20 Federal, State, and local

agencies, collects streamflow,

ground-water level, and water-quality

data throughout Illinois.

Through a network of 149 satellite or

telephone telemetry-equipped

streamflow-gaging stations (about 96

percent of all stations), streamflow

data in Illinois are provided to the

National Weather Service; the

USACE; and other Federal, State,

and local agencies to manage floodcontrol structures and reservoirs, to

plan for flood mitigation, to forecast

streamflow and stream levels, and for

many other activities. Most of this

information can be accessed on the

Internet at http://il.water.usgs.gov/.

Sediment data for rivers and lakes are

needed by researchers, engineers,

water-resource planners, and others

for a variety of applications, and are

essential for monitoring water

quality. Sediment impairs fish

respiration and plant productivity,

and can limit the aesthetic and

recreational usefulness of rivers and

lakes. The USGS, in cooperation with

Federal, State, and local agencies,

collects sediment data at several sites

in Illinois. These sites include small

creeks, reservoirs, and the Illinois and

Mississippi Rivers.