U.S. Department of the Interior

U.S. Geological Survey

USGS Fact Sheet 016-99

June 1999

Iowa

Streamflow-Data Collection

One of the most utilized aspects of

U.S. Geological Survey (USGS)

programs in Iowa is streamflow-data

collection and reporting. The USGS

operates a statewide network of about

120 gaging stations (fig. 1) and

surface-water stage recorders for

Federal, State, and local agencies.

Streamflow information is used by

the National Weather Service during

storms to issue flood warnings and

forecasts and by the U.S. Army Corps

of Engineers (COE) for operating the

four Federal reservoirs in Iowa and

for commercial navigation on the

Mississippi and Missouri Rivers. The

Iowa Department of Natural Resources (DNR) and Department of

Transportation use streamflow data to

monitor the hydrologic conditions of

the State, to provide a historical

database that is used to develop

water-related policy and management

decisions, and to design construction

projects. Local government agencies

use streamflow data for activities

ranging from local flood-warning

systems used to protect lives and

property to providing discharge rates

used in complying with wastewater

discharge permit requirements.

Private citizens and businesses have

access to USGS streamflow data.

In addition to the gaging station

network, the USGS maintains a

statewide network of peak-stage

recording gages on small drainage

basins for the Iowa Department of

Transportation. Data from this

program are used to determine floodfrequency and discharge data for the

numerous small, ungaged drainage

basins in Iowa. Flood-frequency and

discharge data are used by State and

County transportation engineers for

designing bridges and other structures.

The most obvious material flowing

with the water in Iowa’s streams is

suspended sediment. Suspended

sediment can have serious negative

effects for some water users, and it is

an indication of the amount of erosion

in a watershed. The USGS collects

samples and determines the concentration of suspended sediment in

water from sites in Iowa. The COE

uses the data to provide information

on the amount of sediment entering

and potentially depositing in Federal

reservoirs in Iowa and for the Mississippi and Missouri Rivers because of

navigation problems caused by

sediment deposition. The Iowa DNR

is using sediment data as part of landuse and land-management studies to

improve water quality in several

watersheds throughout Iowa.

Drinking Water Supplies

As urban populations grow, communities must obtain additional water

supplies to meet their needs. The

USGS is studying the availability and

quality of ground water in cooperation with several Iowa municipalities.

The USGS is evaluating the alluvial,

sand and gravel aquifer along the

Cedar River near Cedar Rapids and

the Mississippi River at Burlington.

The evaluation is focused on determining the natural relationship of the

river to the aquifer and how the

aquifer is affected by pumping of

nearby wells. Studies are underway at

Cedar Falls and Muscatine to define

areas that contribute recharge to

municipal wells. Water managers can

use this information to develop plans

and policies for protecting the water

supply from potential contaminants.

Spirit Lake

Missouri River

Mississippi

River

Cedar Falls

Cedar Rapids

Burlington

Muscatine

•

•

•

•

Figure 1. Locations of active streamflow-gaging stations in Iowa.
science for a changing world

Flood-Plain Assessments

The flood of 1993 in the lower

Missouri River basin was one of the

most devastating in the history of the

Nation, and it brought national

attention to the lower Missouri River.

Flood-plain management is being

reexamined in the aftermath of the

flooding, taking into consideration

alternatives such as setting back

levees, acquiring and restoring

wetlands, and purchasing flood-plain

easements from farmers. Historical

channel maps and historical vegetation information are critical components used in assessing flood-plain

management alternatives. The USGS

is working on making available, in an

electronic format, historical maps of

the lower Missouri River from

Yankton, S. Dak., to the mouth at St.

Louis, Mo. This information can be

used with other spatial data such as

current channel, levees, land cover,

public ownership, and levee breaks to

evaluate management alternatives.

Evaluation of Restored Habitat

USGS scientists are working as part

of a multiagency cooperative team to

assess the successes of prairierestoration projects in the Eagle Lake

Wetland Complex in north-central

Iowa. Since the late 1980’s, wetlands

have been restored and perennial

grassland has been reestablished on

former cropland in northern Iowa

under the auspices of the North

American Waterfowl Management

Plan and its Prairie Pothole Joint

Venture. The goal is to reconstruct the

prairie lands as functional ecosystems

like they were in colonial days.

Waterfowl are being monitored

through aerial surveys and radiotelemetry studies. Scientists have

identified more than 50 species of

nongame birds on restored prairie

habitats, which represents a diversity

similar to that on tall grass prairie

remnants in Iowa. These data are

intended to be used to assist State and

Federal agencies in planning effective

prairie-restoration projects, and to

modify existing projects to meet

prairie-restoration goals.

Effects of Land Use on Water

Resources

The USGS is participating with the

Iowa DNR and State and Federal

agricultural agencies in studies to

determine the effect of changes in

land use and management on streamflow and water quality in several

small watersheds in Iowa. The

primary purpose of this work is to

implement best management plans in

a watershed and to document the

changes in flow and water-quality

that result from these changes.

In northeastern Iowa, streamflow and

sediment data are being collected

from the Sny Magil and Bloody Run

watersheds. Sny Magil, a small

tributary stream to the Mississippi

River, was selected for implementation of improved land-management

practices to reduce sediment and

nutrient inputs to the stream. Bloody

Run is an adjacent watershed being

measured for comparison.

Streamflow and sediment data are

being collected in the Walnut Creek

watershed in central Iowa. Much of

the Walnut Creek watershed is

included in a recently established

National Wildlife Refuge. Refuge

managers eventually will convert

much of the formerly intensively

farmed land in the watershed to a

restored prairie. This conversion of

land use offers a unique opportunity

to determine its effect on streamflow

and suspended-sediment concentrations at a scale not often available for

study.

Ground-Water Resources

Ground water is the primary source of

drinking water for Iowa’s population.

Information is needed by State and

local governments to understand

trends in water levels and water

quality in the principal aquifers and to

develop policy and management

decisions related to their use. The

USGS collects and compiles waterlevel data from a statewide network

of about 150 observation wells in

cooperation with the Iowa DNR.

Information from this network also is

used by local governments and

individuals requiring information on

the depth to and availability of

ground water at specific locations

throughout Iowa.

A statewide program of ground-water

sample collection and analysis for the

principal aquifers in Iowa is operated

by the USGS in cooperation with the

Iowa DNR and the University of Iowa

Hygienic Laboratory. Data from this

program are used by State agencies to

track trends in water quality at

various locations and depths throughout Iowa and to respond to undesirable concentrations of specific

chemicals, such as pesticides, through

policy and management decisions.

Spirit Lake: Food Supply and

Demand in an Important Fishery

USGS scientists are assessing the

balance between food supply and

demand in Iowa’s most popular lake

fishery, Spirit Lake. Working with the

Iowa DNR, USGS scientists are using

various techniques to assess the abundance and dynamics of forage fishes,

and their capacity for supporting

game fish. Concurrent work on game

fish species such as walleye, northern

pike, largemouth bass, smallmouth

bass, and others is providing estimates of species abundance and

information on the demand and type

of forage consumed (fig. 2).
Iowa

Reducing Deer-Vehicle Collisions

USGS scientists are evaluating the

effects of land use on the incidence of

deer-vehicle collisions in Iowa. These

collisions are a significant problem

for the State, as they are nationwide.

In 1991, 538,000 deer-vehicle collisions occurred along public highways

in the United States. These accidents

caused death and injury to motorists

(and deer) and extensive vehicle

damage. The USGS has developed a

geographic information system for

Iowa that includes road systems, river

corridors, urban areas, public lands,

and landscape cover where deervehicle accidents have occurred.

These data are used to determine the

land-use and habitat characteristics

that have high probabilities for deervehicle collisions. Models developed

from this study are intended to

provide highway and land-use

planners in Iowa and elsewhere the

information needed to reduce deervehicle collisions and increase

motorist safety.

National Water-Quality

Assessment

The Eastern Iowa Basins study being

conducted by the USGS as part of the

National Water-Quality Assessment

Program (NAWQA) has completed

the initial intensive data-collection

phase of implementation (1996–98).

The goals of the program are to

describe the status and trends in water

quality of selected areas throughout

the Nation and to identify factors that

affect their water quality. The Cedar,

Iowa, Skunk, and Wapsipinicon River

Basins are being studied in Iowa.

Reports summarizing data that have

been collected and findings of the

study are being prepared.

Mapping Partnerships

The USGS has been cooperating with

the Natural Resources Conservation

Service (NRCS) and the Farm

Service Agency to produce digital

orthophotoquads (DOQ’s) for Iowa.

DOQ’s are scanned aerial photographs in which distortion and

displacements caused by the camera

orientation and terrain are removed. A

DOQ may be loaded into a geographic information system and used

with other data for analysis and

geographic applications. The NRCS

has been using the DOQ’s as a base to

digitize the soils layer. Other applications of DOQ’s include collecting and

updating land use and land cover,

natural resource inventory and

mapping, delineating field boundaries, and planning applications. Two

thirds of the State of Iowa has DOQ

coverage or DOQ’s scheduled for

production.

The USGS, with the support of State

and local agencies, is producing

digital elevation models (DEM’s) for

the State of Iowa. DEM’s are sampled

arrays of regularly spaced elevations

used for depicting topography. The

high resolution DEM’s can be used

for hydrologic modeling for flood

analysis, streamflow dynamics, and

hazard mitigation.

Ice-Age Winds Recorded in

Loess Deposits

Cooperative studies between the Iowa

DNR-Geological Survey Bureau and

the USGS have resulted in new

insights about ice-age climates. Loess

is a windblown silt that forms some

of the most agriculturally productive

soils in the world (fig. 3). Because

loess was deposited by the wind, it is

Figure 2. A northern pike being sampled to determine the type of prey

items it ate.

.

SD

CO

IA

MN

NE

WI

KS

MO

IL

41°

104° 96°

Loess thickness in meters

> 10

10 – 5

5 – 3

< 3

Ice-age wind direction

0 100 200 300 Miles

0 100 200 300 400 Kilometers

Figure 3. Loess map of Iowa and surrounding region.
Printed on recycled paper

USGS office locations USGS State Representative

Federal Building, Room 269

P.O. Box 1230

400 S. Clinton St.

Iowa City, IA 52244

(319) 337-4191

FAX (319) 358-3606

USGS Home Page:

http://www.usgs.gov

Reports and products:

1-888-ASK-USGS

a direct record of atmospheric circulation, and, therefore, it can be used

to test computer models of ice-age

climates generated by atmospheric

general circulation models

(AGCM’s). Chemical and sediment

studies and AGCM simulations of

climate indicate various directions of

prevailing winds in Iowa during the

last glacial period. Geologic studies

of loess deposits in Iowa are useful

for calibrating computer models of

past climates and verifying the

conclusions of these models.

Iowa Soils and Carbon Cycling

The USGS has inaugurated the

Mississippi Basin Carbon Project to

understand the role of erosion and

deposition in carbon cycling and

carbon dioxide emissions. In Iowa, a

field study of the historic, interactive

exchange of eroding topsoil, carbon

and nutrient loss, and carbon and

nutrient replacement is underway

with the cooperation of U.S. Department of Agriculture-Agricultural

Research Service, U.S. Department of

The USGS has 70

employees in Iowa

Ames

Fort Dodge

Iowa City Council Bluffs

Agriculture-Natural Resources

Conservation Service, Iowa Department of Natural Resources, and

Natural Resources Ecology Laboratory at Colorado State University.

Historic reconstructions of soil

erosion, transport, and soil organic

carbon are based on measurements of

organic carbon, nutrients, and several

Figure 4. Cultivated land adjacent to native prairie.

isotopes. These measurements are

being systematically conducted on a

pair of pristine and cultivated hillslopes to assess the change between

presettlement and modern conditions

(fig. 4). These changes by erosion

profoundly affect soil carbon and

nutrients and, thereby, also affect

carbon dioxide emissions.