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Title: Little Colorado River at Winslow, Navajo County, Arizona, Flood Risk Management Project : Integrated Feasibility Report and Environmental Impact Statement
Authors: United States. Army. Corps of Engineers. Los Angeles District
Keywords: Little Colorado River (N.M. and Ariz.)
Winslow (Ariz.)
Flood control
Environmental management
Environmental protection
Publisher: United States. Army. Corps of Engineers. Los Angeles District.
Abstract: This Final Integrated Feasibility Report (Final IFR) evaluates alternatives to reduce the risk of damages and to reduce the life, safety, and health risks caused by flooding of the Little Colorado River (LCR) to the City of Winslow, surrounding community, and public and private infrastructure. The Final IFR documents the plan formulation and environmental impact analysis conducted by the Corps in close cooperation with the Navajo County Flood Control District, the non-Federal sponsor for this study. The LCR at Winslow study area is located in the middle of the LCR watershed, in and near the City of Winslow in western Navajo County, Arizona. The study area includes the floodplain of the LCR from the Clear Creek confluence downstream (northwest) to the northern end of the existing Winslow Levee. The 49-square-mile study area encompasses the City of Winslow, including the Ruby Wash Diversion Levee, and portions of unincorporated Navajo County. Alternatives include combinations of structural and nonstructural measures such as reconstruction of portions of the existing Winslow Levee and Ruby Wash Diversion Levee, levee setbacks, flood warning system and elevation of residential structures, and river channel conveyance improvements. The Final IFR evaluates the No Action Alternative and ten action alternatives, Alternatives 1.1, 3.1, 7, 8, 9, 10, 10.1, 10.2, 10.3, and 10.4, in detail. The Recommended Plan is Alternative 10.1. Alternative 10.1 includes approximately 4.25 miles of reconstructed or new levees, conveyance improvements consisting of sediment and saltcedar removal, and a flood warning system. The project is designed at a scale that provides a 90 percent assurance of conveying the 1 percent annual chance of exceedance flood. Alternative 10.1 would have temporary and/or permanent impacts, for example, to geology and soils, water quality, groundwater, biological resources, air quality, traffic, noise, utilities, aesthetics, and socioeconomics. The project could also result in adverse and significant impacts to cultural resources; however, most of these impacts are anticipated to be avoided or minimized to below a significant level. Implementation of Alternative 10.1 would reduce the risk of levee overtopping and failure, providing life-safety benefits while lowering the flood risk to critical facilities and infrastructure.
Description: Feasibility Report and Environmental Impact Statement
Rights: Approved for Public Release; Distribution is Unlimited
Appears in Collections:Environmental Documents

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