U.S. Department of the Interior

U.S. Geological Survey

USGS Fact Sheet 028-99

August 1999

Nebraska

The Platte River Ecosystem

The central Platte River Valley is an

internationally significant staging area

for migratory waterbirds of the Central

Flyway. It is best known for the onehalf million sandhill cranes and the

several million waterfowl that migrate

annually through the valley (fig. 1).

Nine endangered species — including

the whooping crane, piping plover,

and least tern — use the central Platte

River Valley for habitat. Irrigation

practices and changes in land use have

transformed the river channel and

altered adjacent wet meadows. Because of these changes, the sustainability of populations of migratory and

resident birds as well as other biota

has been questioned. The central

concern is how the ecosystem has

adjusted to stream-flow reductions. In

developing successful strategies to

sustain or rehabilitate the riparian

ecosystem of the central Platte River,

it is necessary to understand linkages

between geology, soils, hydrology,

channel geometry, biological communities, and ecosystem processes. The

U.S. Geological Survey (USGS) is

conducting interdisciplinary studies to:

• Develop a database on the geology,

hydrology, ecology, geography, and

socio-economic features of the

Platte River Basin.

• Describe the geologic setting of the

Platte River, define the importance

of regional tectonics, local structure, and climate change on the

evolution of the river, describe the

fluvial architecture of sediments in

the valley floor, and place modern

depositional features in a temporal

context.

• Describe interactions among

streamflow, hydraulics, sediment

transport, riparian vegetation, and

channel geometry.

• Develop and apply flow and

sediment-transport models to

examine the interactions of water

management with channel and bank

geometry.

• Develop an understanding of the

interactions between plant and

animal communities of wet meadows and other riparian habitats and

the hydrology and geomorphology

of the river.

Studies of the relations among soils,

vegetation, soil organisms, and

riparian hydrology are intended to

provide important information on

riparian grasslands and factors affecting the food base for cranes and other

birds. Other studies are concentrating

on the role of the Platte River ecosystem as an important site for fat acquisition for migrant cranes and waterfowl. Scientists are studying how

competition from growing numbers of

geese, habitat loss, and increasing

efficiency of corn harvesting techniques contribute to the declining rate

of fat storage in cranes. Biologists are

tracking cranes marked with satellite

transmitters to determine how long

individual cranes stop at the Platte,

where they breed, and where they

winter. This will provide a better

understanding of their habitat needs

and the role of the Platte Valley in

supplying those needs. A companion

study is addressing the diets, activities,

and acquisition of fat and protein by

lesser snow geese, greater white

fronted geese, and northern pintails

during spring migration in Nebraska.

Biological information will be incorporated into ongoing geologic and

hydrologic models of the Platte River

Figure 1. Sandhill cranes prefer unobstructed river channels as roosting sites.
science for a changing world

to determine the extent of changes to

riparian habitats and their significance

to key habitats and wildlife species.

The program is a cooperative effort

between the USGS and many other

Federal, State and local agencies and

private entities. Coordination is being

conducted, in part, through USGS

participation in working groups related

to the Platte River Endangered Species

Partnership.

Republican River Basin GroundWater Flow Model

Streamflows have declined in the last

50 years in the Republican River

Basin in southwestern Nebraska,

northwestern Kansas, and northeastern

Colorado (fig. 2). The declines have

led to conflicts over water in the basin,

culminating with Kansas filing a

lawsuit in 1998 against Nebraska,

alleging violations of the 1942 Compact allocating water among basin

states. At issue is the effect of irrigation development from the High Plains

aquifer on streamflows in the basin.

The USGS is conducting a study, in

cooperation with the Nebraska Republican River Basin Management

Districts and the Southwestern Nebraska Resource Conservation and

Development Area, to evaluate

ground-water flow and the interaction

between ground water and surface

water. The objectives are to quantify

ground-water and surface-water

interaction throughout the basin and to

simulate the effects of future pumping

on streamflow. Ground-water flow

modeling is being used to predict flow

conditions at specific locations in the

aquifer. Data on aquifer physical

characteristics, inflows, and outflows

are being compiled for the 30,000-

square-mile study area. Model results

will be compared to measured values.

The study is intended to provide a

ground-water model that managers can

use to estimate the effects of different

ground-water pumping plans on

streamflow in the basin. The results

are intended to enable basin water

managers to make decisions about

ground-water and surface-water

resources based on an improved

understanding of the aquifers and their

interaction with the Republican River.

Field studies to investigate groundwater and surface-water interaction at

three locations along selected principal

tributaries of the Republican River

also are being conducted in southwest

Nebraska (fig. 2). These studies are

intended to improve understanding of

the dynamics of ground-water and

surface-water interaction and will be

compared to the modeling results.

Water samples also are being collected

from more than 300 irrigation wells in

the Nebraska part of the basin to

determine the water quality in the

High Plains aquifer, which is the

primary source of drinking water in

the study area.

Grassland Birds

Bird species native to the North

American grasslands have shown

steeper, more consistent, and more

geographically widespread declines

than any other group of birds during

the last quarter of a century. To

understand why bird species are

declining, USGS scientists are comparing population data on native

grassland bird species (fig. 3) with

data on biological, physical, and

human-use factors. The analysis

includes such factors as habitats,

management practices, and land use,

and uses a geographic information

system (GIS) to identify patterns of

change in bird populations. Field

efforts range from Montana to

Mexico. Partners include State game

and fish agencies, the Bureau of Land

Management, U.S. Fish and Wildlife

Service, National Park Service,

nongovernmental organizations such

as the Nature Conservancy, other

private organizations, and individuals.

Figure 2. Republican River study area and locations of ground-water/surfacewater interaction study sites.

Republican River Frenchman Creek

Platte Riv e r South

Platte River

Little Blue River

North Fork Solomon River

South Fork Solomon River

Smoky Hill River

Saline

South Fork Republican River

North Fork Republican River

River

COLORADO

KANSAS

NEBRASKA

0 25 50 75 100 Miles

0 25 50 75 100 Kilometers

104°

41°

39°

103° 102° 101° 100° 99° 98°

40°

Study Area

COLORADO KANSAS

NEBRASKA

Ground-water/surface-water interaction study sites
Nebraska

Prairie Dog Surveys

The USGS is working with the U.S.

Forest Service and other Federal,

State, and private agencies to survey

colonies of black-tailed prairie dogs in

the northern Great Plains. The study

uses sampling based on remote

imagery obtained during aerial

surveys.

The Climate of the Last

Interglacial Period in Nebraska

The last interglacial period (LIG) was

the most recent time when global

climates are thought to have been

significantly warmer than now. The

USGS is studying the LIG to understand the geographic scope and impact

of future warm climates.

LIG pollen and fossil records from

Midcontinental North America are rare

compared to those in Europe. Where

pollen or fossil records are absent, the

climate of the LIG in the North

American Midcontinent may be

inferred from properties of a buried

loess (wind-blown silt), called the

Sangamon loess, that formed during

this period. The Sangamon loess

formed in Nebraska between about

130,000 and 45,000 years ago.

Modern loesses in a Midcontinent line

from Ohio to Colorado show distinct

changes in distribution particularly

over the forest-prairie boundary,

which, in presettlement time, was in

Illinois. Sangamon soils in this same

line indicate that the forest-prairie

border may have been west of its

present boundary by as much as 310

miles, in eastern Nebraska. This

indicates higher precipitation than at

present during at least parts of the

LIG.

Comparisons of geologically based

reconstructions of climate to atmospheric general circulation model

(AGCM) simulations are used to

forecast future climates. Both AGCM

results and geologic data indicate

higher temperatures in the Midcontinent and high latitudes of North

America during the LIG. However, the

greater precipitation in the Midcontinent shown in the geologic record of

the LIG contradicts the AGCM results,

which indicates that precipitation was

similar to or even less than present

during this period. This suggests that

AGCM’s are better at simulating

temperature fields than they are at

simulating precipitation fields.

Statewide Digital Mapping

Partnership

The Nebraska Natural Resources

Commission (NNRC) entered into a

workshare partnership agreement with

the USGS to develop digital orthophoto quadrangles (DOQ) (precisely

rectified, highly accurate, digital aerial

photographic images) covering the

State of Nebraska. New digital

elevation model (DEM) data sets, an

array of regularly spaced elevations,

also were produced for most of the

State as part of the partnership agreement. There are hundreds of GIS

applications for which these digital

products can be used to benefit the

citizens of Nebraska. Urban sprawl

and rural development, emergency

management, water modeling, and

numerous other natural resource

management issues can be effectively

addressed utilizing statewide DOQ

and DEM data sets. The NNRC

Internet address for this information is

http://www.nrc.state.ne.us/docs/

frame4.html

Stream-Channel Stability

Many stream channels in eastern

Nebraska were altered in the early

1900’s to help alleviate flooding.

Channel straightening is recognized as

a cause of channel-stability problems,

such as downstream deposition and

upstream degradation and widening of

the channel, which are hazards to

roads and bridges. In addition, channel

banks, which comprise highly erodible

soils, were severely eroded by the

floods of 1993. Many small county

bridges failed or were closed as a

result of the floods.

The USGS, in cooperation with the

Papio-Missouri River and Lower

Platte South Natural Resources

Districts, the Nebraska Department of

Roads, the NNRC, the Federal Highway Administration, the University of

Nebraska-Lincoln (UNL), the Agricultural Research Service, and the U.S.

Army Corps of Engineers, is examining the effects of channel instabilities

on bridge structures and flood-plain

resources in a 23-county area of

eastern Nebraska.

Improved methods for anticipating

future channel stability and geometry

and the identification of possible types

of remediation measures to stabilize

the channels are intended to benefit

planners, structural designers, and

resource managers.

Historic Channels near Rulo

The flood in 1993 in the lower Missouri River Basin has reinforced the

need to evaluate the effectiveness and

cost of current flood mitigation and

management methods to maintain

flood-plain ecosystems, wetlands, and

facilities along the Missouri River and

Figure 3. Mountain plover.
Printed on recycled paper

USGS office locations USGS State Representative

406 Federal Building

100 Centennial Mall North

Lincoln, NE 68508

(402) 437-5082

FAX (402) 437-5139

USGS Home Page

http://www.usgs.gov

Reports and products

1-888-ASK-USGS

its tributaries. Historic channel maps

near the town of Rulo have been

created to assess potential restoration

sites, identify areas affected by

flooding, and determine river-management alternatives.

Contaminated Ground Water

After operating for more than 100

years, a lead refinery in Omaha,

Nebraska, on the banks of the Missouri River, closed. Discharges from

the refinery commonly exceeded

water-quality standards for lead,

arsenic, zinc, and antimony. Currently,

the contamination threat is from

ground water that moves from beneath

the facility into the Missouri River.

USGS scientists are conducting

toxicity tests using ground water, river

water, and sediments to document if

the metals present are available to fish

and wildlife, and if they are, to what

extent they are toxic. This research is a

cooperative project with the U.S.

Environmental Protection Agency to

provide data for clean-up efforts at the

facility.

Omaha-Kansas City Urban

Corridor Geologic Map Project

The Omaha-Kansas City corridor is a

major population center where rapid

urbanization and development of

resources that support urbanization are

in conflict with agricultural land use

(fig. 4).

This cooperative project, between the

Conservation and Survey Division

(CSD) at the University of NebraskaLincoln (UNL) and the USGS, is

preparing surficial materials maps that

are intended to help planners and

others address urban, ground-water,

and agricultural land-use issues as well

as help them evaluate geologic hazards

and constraints in this area.

Maps of surface and subsurface

materials in the Greater Omaha area

(about 500 square miles) in eastern

Nebraska and western Iowa and in the

St. Joseph area (about 660 square

miles) in northwestern Missouri and

northeastern Kansas will display

details of surficial deposits at scales of

1:100,000 and 1:62,500, respectively.

The maps will provide data such as

thickness and distribution of loess and

glacial deposits, depth to bedrock, and

extent of buried glacial drainageways.

These and other map data are intended

to aid in resolving ground-water,

aggregate resource, and environmental issues in rapidly growing areas in

the corridor. For example, buried

glacial drainageways are excellent

sources of ground water because they

commonly contain coarse sand and

gravel, but they may be susceptible to

contamination if they are shallow.

Figure 4. Cows and condos compete

for the same land.

The USGS has 38

employees in Nebraska

North Platte

Ord

Lincoln

Statewide National Aerial

Photography Coverage

The National Aerial Photography

Program (NAPP) began collecting

aerial photography for the State of

Nebraska in February–April 1999.

This multipurpose photography will

be used to update the 1993–94 DOQ

image base for Nebraska. The uses for

NAPP photographs include naturalresource management; disaster and

hazards planning, mitigation, and

response; property assessment;

agriculture; education; and recreation.

Hydrologic Data Collection

The USGS, in cooperation with more

than 25 Federal, State, and local

agencies, collects streamflow and

ground-water data at numerous sites

throughout Nebraska. These data are

critical for administering and managing water resources, determining the

extent and severity of droughts, and

describing and predicting conditions

during floods, and monitoring effects

of human activities. In addition,

ground-water-level and groundwater-quality data collected throughout Nebraska provide important

information for water-resource

managers. These data are published

annually in a report titled “WaterResources Data—Nebraska,” and are

available on the Internet at http://

www-ne.cr.usgs.gov/index-neb.html