FLOOD04472

• County: Statewide
• Community: Nemaha County Nebraska
• Stream Name: Missouri River Miles 532.4-528.9
• Basin: Statewide
• Title: Langdon Bend Habitat Restoration/Preservation Project Volume 1
• Date: 6/1/1995
• Prepared For: US Army Corps of Engineers
• Prepared By: Greenhorne & O'Mara, Inc.
• Floodplain - Doc Type: Project

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Plains Section of the Central Lowland physiographic province. The project site is relatively flat
with an approximate average elevation of 885 to 890 feet above mean sea level (USGS 1984).
The northern portion of the property, including a border along the rivers edge, is relatively flat
natural forest land with natural terraces, trenches and earth mounds. The central and southern
portions of the property are farmland of low relief. Historical maps of this area indicate that the
river channel had changed course several times prior to channelization (Bedford & George 1857,
Post Office 1912, NE Department of Roads and Irrigation 1938). Remnant depressional areas
and drainage patterns from the previous bank overflows are evident. These areas presently hold
water during high stage events. Approximately 3.5 miles of the main Missouri River channel
(river miles 528.9 to 532.4) border the site to the east.

The soils of the project site are primarily of the Haynie-Onawa-Albaton association (USDA
1982). The Albaton-Haynie-Onawa association consists of deep, nearly level, moderately well-
drained to poorly drained silty and clayey soils that formed in alluvium on bottomlands and are
subject to flooding (Exhibit 3). Some of the wetter and more sandy areas which are not in
agriculture support native vegetation. These areas have good potential for wildlife habitat and for
the production of a limited amount of cottonwood timber.

b. Water Quality: According to the Nebraska Department of Enviromnental Quality,
there is no quantitative water quality data available for the Langdon Bend area (Callam, pers.
comm.). The water quality of the backwater areas at the Langdon Bend site is likely to be
consistent with its primary water source, the Missouri River. Because the site has been used for
and is surrounded by agricultural land, the presence of residual pesticides, herbicides, and
fertilizers may be expected (U,S. Army Corps of Engineers 1993). The levels of residual
pesticides and herbicides which would normally be found in an agricultural community would
pose a very low potential for adverse effects to habitats after the activities cease.

The swales on the property where water collects would experience high temperatures and
low dissolved oxygen concentration following floods and heavy rains, This would be due to the
shallow nature of the water, the lack of flow, and the absence of mixing with the Missouri River
except during high river stages. These conditions would be expected in backwater areas with little
or no hydraulic connection to the main stem of the Missouri River or its tributaries.

c. Air Quality: Increased suspended particulate matter and air pollution are the result
of agricultural and boating activities adjacent to and on the project site. There have been no
violations of the National Ambient Air Quality Standards (NAAQS) in Nemaha County, Nebraska,
The project area is in attainment of NAAQS according to the Nebraska Department of Natural
Resources (McCrory, pers. comm.).

d. Noise: Sources of noise on and around the project site result from recreational
boating, commercial barges, hunting and agricultural activities. These activities are seasonal.
In the spring and fall there is an increased use of tractors and trucks on and adjacent to the project
site.

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