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I I I I I I I I I I I I I I il I I I I investigated on a case-by-case basis for their technical feasibility, and may be modified as further planning and design occurs. b. Selection Process: The Langdon Bend area was selected as a development project in the State of Nebraska after on-site evaluations and review of existing aerial photography and site plans. After preliminary investigations and studies were conducted, the Nebraska Game and Parks Commission (NGPC) nominated the site as a candidate for planning, design, and construction. Most of the site is owned by the Corps, 3. AFFECTED ENVIRONMENT The Missouri River Bank Stabilization and Navigation Project authorized charmelization of the Missouri River from Sioux City, Iowa to the confluence with the Mississippi River in 1935. The majority of the work was completed between 1945 and 1965. Rock revetments and pile dikes were used to reduce the wide cross-section of the river by cutting off side charmels and shallow sand-bar complexes, Sediment aggraded within areas which were previously wet, and the charmel was eventually stabilized into a narrow corridor about 600 feet wide. Channelization has altered overbank flooding patterns, isolated the floodplain from the river, and increased water velocities in the channel (Fredrickson and Reid 1990). Prior to channelization, the Missouri River was uncontrolled and meandered across the river valley causing erosion, deposition, and accretion, The channel "consisted of numerous islands, channels, chutes, sandbars, and back-water areas supporting vegetation in various stages of succession. The meander belt consisted of a 606,000-acre area adjacent to the natural channel. This area consisted of successional wetlands and various types of herbaceous and woody habitats, as well as some form of agricultural use. It is estimated that over 500,000 acres of aquatic and terrestrial habitat will have been eliminated from the natural channel and meander belt by the year 2003," (U.S. Army Corps of Engineers 1990). The Missouri River system in its natural state provided a diversity of habitats for fish and wildlife. Historically, it contained large populations of fishes and a diversity of species. These have been affected by the loss of water surface area and habitat. The Missouri River and associated habitats support many mammals, reptiles, amphibians, songbirds, shorebirds, and waterfowl. Channelization has resulted in a general reduction in wildlife numbers due to changes in habitats. An assessment of the existing environment at Langdon Bend has been completed for this DPR. This assessment included: research of existing reports, maps, and aerial photographs; field investigations of current site conditions; and consultation with resource agencies. Results of the various investigations are sununarized below. a. Physiography and Topography: The Langdon Bend site is located in the floodplain of the Missouri River in Nernaha County, Nebraska and is part of the Dissected Till 8