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Title: Water Quality Sampling Report and Factual Determinations : Results of Sediment Sampling and Elutriate Testing at the Proposed Langdon Bend Top-Width Widening Shallow-Water Habitat Project Site
Authors: United States. Army. Corps of Engineers. Omaha District
Keywords: Water quality
Aquatic habitats
Pallid sturgeon
Sedimentation and deposition
Environmental management
Environmental protection
Publisher: United States. Army. Corps of Engineers. Omaha District.
Abstract: The U.S. Army Corps of Engineers (USACE) is constructing shallow-water habitat (SWH) along the lower Missouri River downstream of Gavins Point Dam to mitigate aquatic habitat lost from past bank stabilization and channelization. The constructed SWH projects are intended to help meet the SWH acreage goals of the U.S. Fish and Wildlife Service’s (USFWS) 2003 Amendment to the 2000 Biological Opinion on the Operation of the Missouri River Main Stem Reservoir System, Operation and Maintenance of the Missouri River Bank Stabilization and Navigation Project, and Operation of the Kansas River Reservoir System (BiOp), and thus provide habitat for the endangered pallid sturgeon (Scaphirhynchus albus) and other native fish and aquatic species. A major element of the reasonable and prudent alternative from the BiOp includes the restoration of 20-30 acres per mile (5.0-7.5 hectares per kilometer) of SWH on the lower Missouri by 2020. General criteria for defining SWH include depths less than 5 feet (1.5 meters) and current velocities of less than 2 feet/second (0.6 meters/second). The SWH projects on the lower Missouri River are being constructed as part of the Corps’ Missouri River Recovery Program). A project is being proposed to construct SWH along Langdon Bend of the Missouri River between RM529 and RM532. The Omaha District (District) is referring to the proposed project as the Landon Bend Top-Width Widening Project (LBTWWP). The proposed project is located in Nemaha County, NE just downstream of Brownsville, NE and east of Nemaha, NE. The District plans to construct SWH by creating cutback areas at each end of the project site and constructing a low through chute between the cutback areas. The removal of deposited sediment will involve hydraulic dredging and it is proposed that the dredge spoil be discharged to the adjacent Missouri River. It is believed that some of the sediment to be dredged was newly deposited during the Missouri River flood of 2011 and will be primarily sand with some silts and clays. It is estimated that up to 800,000 cubic yards of sediment could be excavated and discharged to the Missouri River. The intent of this report is to provide Factual Determinations of the potential water quality impacts of the proposed hydraulic dredging discharge at the LBTWWP site on the Missouri River. As defined in the Federal CWA and USACE Regulation No. 1110-2-8154, water quality is defined as the physical, chemical, and biological characteristics of water.
Description: Technical Report
Rights: Approved for Public Release; Distribution is Unlmited
Appears in Collections:Technical Reports