U.S. Department of the Interior

U.S. Geological Survey

Introduction

Wetlands recently have received

political and scientific attention because of their known benefit to the

environment. For example, wetlands

decrease the effects of flooding by

storing large quantities of water in

porous streambank sediments and

low-lying areas. Extensive flooding in

some areas of the United States has

been attributed in part to the loss of

wetlands (Fretwell and others, 1996).

Wetlands also have been shown to

improve water quality by filtering out

fertilizers and pesticides. The organicrich sediments of wetlands, produced

by decaying plant mass, attract and

bind other contaminants as well;

many communities nationwide are

constructing wetlands to enhance

sewage-treatment systems.

The U.S. Geological Survey and the U.S. Environmental Protection Agency are jointly studying the hydrology of a long-existing natural wetland and

a recently restored wetland in the Kankakee River Valley in northwestern Indiana. In characterizing the two wetlands, project investigators are testing

innovative methods to identify the analytical tools best suited for evaluating the success of wetland restoration. Investigators also are examining and

comparing the relations between hydrology and restored wetland vegetation.

A Study of Natural and Restored Wetland Hydrology

Figure 1. Location of the study area in northwestern

Indiana.

vative methods to identify the analytical

tools best suited for evaluating the success

of wetland restoration.

Background

Prior to European settlement, wetlands in

the Kankakee River Basin formed a continuous

ecosystem from north-central Indiana to northcentral Illinois. The Kankakee River system

was then the largest wetland in the midwestern

United States and gained international recognition during the 1800’s for its diverse

wildlife and excellent hunting and

fishing opportunities. With European

settlement, the flat valley floor became

highly desired as farmland. A vast

tile and ditch network was developed

to lower ground-water levels beneath

low-lying lands adjacent to the Kankakee River to make those lands

agriculturally productive. An extensive levee system also was built to

reduce flooding near the river. As a

result, the hydrologic conditions that

had sustained the wetlands in the

Kankakee River Basin were altered.

Today, only 13 percent of the original

wetlands of the Kankakee River Basin

remain intact, and the populations

of many species of fish, plants, and

wildlife have declined steadily in

response to reduced and degraded

wetland habitat.

In 1998, the U.S. Fish and Wildlife

Service proposed restoration of 30,000

acres of the historical wetland over

the next 30 years, and the U.S. Army

Corps of Engineers began examining

techniques to minimize the effects of

periodic flooding. The purpose of the

restoration would be to conserve, protect, and enhance fish and wildlife

habitat in the Kankakee River Basin.

One plan to accomplish this goal is to

As part of a U.S. Environmental Protection Agency Ecosystem Restoration

Initiative grant, a joint U.S. Geological

Survey (USGS)/U.S. Environmental

Protection Agency (USEPA) study is

looking at the hydrology of a natural

wetland (the LaSalle Fish and Wildlife

Area) and a restored wetland (the

Grand Kankakee Marsh County Park)

(fig. 1). Project investigators are examining and comparing the relations between

hydrology and vegetation in the natural

and restored wetlands while testing inno41 

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41 30' Kankakee River Basin

MICHIGAN

LAKE MICHIGAN

ILLINOIS

Grand Kankakee Marsh

County Park, Lake County, Ind.

LaSalle State Fish and 

Wildlife Area, Newton County, Ind.

MILES

0 KILOMETERS

0 20

20 40

40

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INDIANA

Ka n kakee R i ver
plug and remove parts of the extensive

tile and ditch network to allow ground

water to return to historical levels.

Goals of the Study

The USGS/USEPA study will (1) determine the applicability of various

naturally occurring isotopes of chemical

elements (many of which have not

commonly been applied in wetlands

investigations) to discriminate between

ground- and surface-water-flow paths,

recharge and discharge areas, water residence times, and source areas in natural

and restored wetlands; (2) develop a

method to assess the hydrology of natural,

constructed/relocated, and restored wetlands; (3) use computer-based models

to simulate ground- and surface-water

flow and chemical transport through the

studied wetlands to corroborate the isotope results, as well as to forecast the

effects of wetland restoration on adjacent

properties; (4) characterize general water

quality at both sites to differentiate between the natural and restored wetlands;

and (5) develop statistical relations

between established plant communities

and wetland hydrology.

Information gained from this study

may be applicable to wetlands investigations nationwide. In many parts of the

country, destruction of natural wetlands

is permitted if a wetland is constructed

at another location. Constructed or relocated wetlands, unlike restored wetlands,

commonly are built where a wetland

has not existed previously. Research by

USGS/USEPA scientists has found that

wetland functions, such as water-quality

improvement and decreased flooding

intensity, partially are reconstituted in

restored wetlands but probably are

not reestablished in constructed or

relocated wetlands (Hunt, 1996). The

USGS/USEPA study will provide

additional information describing the

hydrology of restored wetlands. General

observations in this study also may be

applicable in other studies of manmade

wetlands.

State of the Science

Recent research has focused on the

details of wetland functions such as

water-quality improvement, floodwave

suppression, and ground-water/surfacewater interactions (Krabbenhoft and

Webster, 1995; Anderson and Cheng,

1993; Mills and Zwarich; 1986). These

studies have shown that these wetland

functions are correlated with recharge and

discharge areas, ground-water-flow paths

and rates, and soil-profile development.

The location of recharge and discharge

areas can change in response to seasonal

or weather-related factors and can affect

ground-water-flow direction. As a result,

ground- and surface-water quality are

affected. The presence of various

wetland-plant communities may reflect

these changing conditions.

Computer simulations of ground-water

flow through wetlands may not be as

useful as once believed (Hunt, 1996; Hunt

and others, 1996, 1997). Accurate simulations of wetland-flow systems require

detailed measurements of hydrologic

properties at finer scales and frequencies

than commonly are made.

The use of naturally occurring isotopes

can be superior to traditional waterquality analyses for elucidating the details

of wetland hydrology (Hunt and others,

1998; Kehew and others, 1998). In

addition, the conjunctive use of isotope

analyses and computer simulations results

in more accurate predictive capabilities

than can be achieved without the isotopic

information.

Study Sites

Sites for the USGS/USEPA study are

at the Grand Kankakee Marsh County

Park in Lake County, Ind., and at the

LaSalle State Fish and Wildlife Area in

Newton County, Ind. Both study sites

are adjacent to the Kankakee River.

At both sites, the geology consists of

unconsolidated sand, underlain by clayrich glacial-lake deposits and a basal

bedrock. A previous USGS hydrologic

investigation provided some background

information (Arihood and Basch, 1994).

The Grand Kankakee Marsh County

Park is a wetland-restoration project

managed by the Lake County Parks

Department. Wetland restoration

began in 1979 and the Parks Department continually is adding new property

to its boundaries; the total area is currently 1,900 acres. The restored wetland

provides refuge and nesting areas for

migratory waterfowl and hunting opportunities for local enthusiasts.

The wetland at Grand Kankakee

Marsh County Park had been cultivated

prior to wetland restoration. A system of

pumps, drains, and ditches is used to manage water levels in the wetland. Water

from the Kankakee River and the Brown

Levee Ditch is used to flood low-lying

areas within the wetland. The Kankakee

River and the Brown Levee Ditch form

the south and the north boundaries of the

Park.

The LaSalle Fish and Wildlife Area,

which was dedicated in 1964, includes

approximately 3,700 acres of land. The

USGS/USEPA study site is a remnant

of the historical wetlands of the Kankakee

River Basin and includes sloughs and

sedge meadows in a matrix of upland oak

savannas (fig. 2). There are no artificial

controls on water levels at the LaSalle

study site, and parts of the site are seasonally inundated.

Figure 2. A sedge meadow within the oak

savanna at LaSalle State Fish and Wildlife

Area.
Instrumentation and

Data Collection

The geologic simplicity at the study

sites along the Kankakee River, the

quantity and precision of hydrologic

information collected, and the extensive data base of isotope and

water-quality analyses help provide a

clear conceptualization of the hydrologic

and water-quality processes occurring

in the wetlands. An accurate conceptualization and a data base of precisely

measured hydrologic properties are

required for computer simulations of

wetland hydrology.

At both sites, a transect was selected

that parallels the local ground-waterflow direction and is perpendicular to

the Kankakee River. Wells were installed

along each transect in nests of two or

three wells, and each well was drilled to

a different depth. All of the wells drilled

for this project were completed in the

surficial sand aquifer. Existing wells

belonging to private landowners, the

LaSalle Fish and Wildlife Area, and

the Lake County Parks Department were

completed in bedrock and were included

in the study-site well transects.

Additional instrumentation installed

at the Grand Kankakee Marsh County

Park (fig. 3) measures rainfall, humidity,

atmospheric pressure, air temperature,

ground-water temperature, and surfaceand ground-water levels. Water samples

collected at more than 60 points at the two

sites represent rainfall, saturated- and

unsaturated-zone ground water, ditch

and stream water, and seepage into

shallow wetland ponds. The water

samples are being analyzed for about

40 constituents, including major ions,

trace elements, and nutrients.

In addition to the continuous measurements made by site instrumentation,

ancillary hydrologic data have been

collected. Ancillary data include detailed

topographic maps of the land surface

and records of pumping and other parkmanaged controls on water flow into

and out of the restored wetland.

Aquifer and streambed permeability,

which strongly affect the rate at which

water flows into and out of the wetlands,

are being estimated by use of aquifer

pump-and-recovery tests and floodwaveresponse analyses (Barlow and Moench,

1998; Duffield, 1998). These estimated

values, which are used as input to the

computer models of the wetland flow

system, can in turn strongly affect the

accuracy of the simulations (described

below).

Isotope Studies

Atoms of an element that have the

same number of protons but a different

number of neutrons are isotopes of that

element. Naturally occurring isotopes

of many chemical elements exist in

ground and surface water and can provide

information about the hydrologic and

geochemical history of the water in a

wetland (Sidle, 1998). Samples for isotopic analysis usually are collected with the

same techniques and tools that are used to

collect samples for general water-quality

analysis, although some require specialized devices.

Most wetland studies have made use

of a few basic isotopes, such as those

of oxygen and hydrogen. This study is

examining the use of the isotopes of

oxygen, hydrogen, carbon, nitrogen,

sulfur, strontium, lead, and chloride

(table 1). In other studies these isotopes

have been used to calculate the contribution of ground water to streams and lakes,

to estimate the residence time of water

in an aquifer, to indicate specific rockwater interactions, to differentiate

between agricultural and naturally occurring nutrients, and to infer biologically

mediated reactions occurring in ground

water (Clark and Fritz, 1997). Isotopic

analyses for this study are being done

at the USEPA National Risk Management

Laboratory in Cincinnati, Ohio, and at

Purdue University in Lafayette, Ind.

Table 1. Naturally occurring isotopes used

in this study

[1, provides information about ground-water

sources; 2, provides information about the

ground-water-flow-path history; 3, provides

data for estimating ground-water residence times;

4, provides information about biochemical

modifications to water chemistry]

Compounds Isotopes Uses

Oxygen 18O/16O 1, 2

Hydrogen 2H/1H 1, 2

Carbon 13C/12C 1, 2, 3, 4

Nitrogen 15N/14N 1, 2, 4

Sulfur 34S/32S 1, 2, 4

Strontium 87Sr/86Sr 1, 2

Lead 206Pb/204Pb 1, 2

Chloride 36Cl/total Cl 3

Computer Simulations of

Wetland Hydrologic Processes

The accuracy of a computer simulation

of a hydrologic system such as a wetland

depends on the quality of data used as

input for the computer program. Through

the study-site instrumentation, the USGS

and USEPA are making detailed measurements of many of the variables necessary

to characterize accurately a wetland

hydrologic system.

Figure 3. Aerial view of the restored wetlands at Grand Kankakee Marsh County Park. The photo

was taken from above the Kankakee River, looking toward the northeast. (Photograph by

Marc Robertson, Lake County Parks Department.)

modifications to water chemistry]
The simulations of wetland hydrology

will be done using the computer code

commonly known as MODFLOW

(McDonald and Harbaugh, 1988).

This code uses the field-measured data

and the researcher’s conceptualization

of the flow system to solve a set of

mathematical equations and produce a

three-dimensional array of ground-waterflow rates and directions. The effects

of various restoration activities on local

ground-water levels will be simulated

by adjusting the model input and conceptualization. The computer simulations

developed from this information will

be used to predict the effects of wetland

restoration on the existing hydrology

of the wetlands and adjacent farmlands

and to suggest residence times and

transport pathways of surface water

and ground water.

Vegetation and Hydrology

Relations between hydrologic variables and wetland vegetation are being

examined at both study sites. The composition and richness of the vegetation are

being sampled at 10 plots adjacent to

ground-water observation wells where

information exists to describe the hydrology. Relations between hydrology and

vegetation will be derived by statistical

analysis of the data.

Study Results

The USGS/USEPA study described

here began in October 1997 and is scheduled to extend through September 2000.

Analysis of data collected since the

study’s inception is underway; initial

results are scheduled for publication in

1999. Additional results will be published

throughout the study period as more data

become available. Professional journals

are the targeted outlets for publication of

these results.

—E. Randall Bayless,

Leslie D. Arihood, William C. Sidle,

and Noel B. Pavlovic

References

Anderson, M.P., and Cheng, Xiangxue,

1993, Long- and short-term transience in a groundwater/lake system

in Wisconsin, USA: Journal of

Hydrology, 145, p. 1–18.

Arihood, L.D., and Basch, M.E., 1994,

Geohydrology and simulated

ground-water flow in an irrigated

area of northwestern Indiana:

U.S. Geological Survey WaterResources Investigations Report

92-4046, 38 p.

Barlow, P.M., and Moench, A.F.,

1998, Analytical solutions and

computer programs for hydraulic

interaction of stream-aquifer

systems: U.S. Geological Survey

Open-File Report 98-415A,

85 p.

Clark, I.D., and Fritz, Peter, 1997,

Environmental isotopes in Hydrology, Boca Raton, Fla., Lewis

Publishers, 328 p.

Duffield, G.M., 1998, AQTESOLV

for Windows User’s Guide:

Reston, Va., Hydrosolve, Inc.,

128 p.

Fretwell, J.D., Williams, J.S., and

Redman, P.J. (compilers), 1996,

National Water Summary on

Wetland Resources: U.S. Geological Survey Water-Supply

Paper 2425, 431 p.

Hunt, R.J., 1996, Do created wetlands

replace the wetlands that are

destroyed?: U.S. Geological

Survey Fact Sheet FS-96-246,

4 p.

Hunt, R.J., Krabbenhoft, D.P., and

Anderson, M.P., 1996, Groundwater

inflow measurements in wetland

systems: Water Resources Research,

v. 32, no. 3, p. 495–507.

Hunt, R.J., Krabbenhoft, D.P., and

Anderson, M.P., 1997, Assessing

hydrogeochemical heterogeneity

in natural and constructed wetlands:

Biogeochemistry, 39, p. 271–293.

Hunt, R.J., Bullen, T.D., Krabbenhoft,

D.P., and Kendall, C., 1998, Using

isotopes of water and strontium

to investigate the hydrology of a

natural and a constructed wetland:

Ground Water, v. 36, no. 3,

p. 434–443.

Kehew, E., Passero, R.N., Krishnarurthy,

R.V., Lovett, C.K., Betts, M.A.,

and Dayharsh, B.A., 1998, Hydrogeochemical interaction between

a wetland and an unconfined

glacial drift aquifer, southwestern

Michigan: Ground Water, v. 26,

no. 5, p. 849–856.

Krabbenhoft, D.P., and Webster, K.E.,

1995, Transient hydrogeological

controls on the chemistry of

a seepage lake: Water Resources

Research, v. 31, no. 9, p. 2295–2305.

McDonald, M.G., and Harbaugh, A.W.,

1988, A modular three-dimensional

finite-difference ground-water

flow model: U.S. Geological Survey

Techniques of Water-Resources

Investigations of the U.S. Geological

Survey, book 6, chap. A1, not

sequentially paginated.

Mills, J.G., and Zwarich, M.A., 1986,

Transient groundwater flow

surrounding a recharge slough in

a till plain: Canadian Journal of

Soil Science, v. 66, no. 1,

p. 121–134.

Sidle, W.C., 1998, Environmental

isotopes for resolution of hydrology

problems: Environmental Monitoring Assessment, v. 52, p. 389–410.

For More Information

 District Chief Indiana District Website

 U.S. Geological Survey http://in.water.usgs.gov

 5957 Lakeside Boulevard

 Indianapolis, IN 46278 U.S. Geological Survey Website

 317-290-3333 http://www.usgs.gov

Fact Sheet FS-104-99

May 1999