Finding of No Significant Impact & Tiered Environmental Assessment: Public Law 84-99 Rehabilitation Program Dry Creek Flood Risk Reduction Project Hawarden, Sioux County, Iowa.

摘要

In accordance with the National Environmental Policy Act (NEPA) and implementing regulations, a Programmatic Environmental Assessment (PEA) for the Public Law (PL) 84-99 Rehabilitation Program in the U.S. Army Corps of Engineers, Omaha District (Corps) was finalized on December 27, 2011 and is incorporated by reference herein. This project-specific NEPA review is tiered off the programmatic document to determine if the proposed repairs meet the description and criteria of the Recommended Alternative as described in the PEA. This tiered assessment meets the requirements of the NEPA of 1969, as amended (42 U.S. Code [USC] 4321 et seq.); the President s Council on Environmental Quality (CEQ) Regulations (40 Code of Federal Regulations [CFR] 1500 1508) and Corps Engineer Regulation (ER) 200-2-2 (33 CFR 230). In June 2014, record rainfall in South Dakota, Minnesota, and northwestern Iowa caused unprecedented flooding along the Big Sioux River. High flows from the Big Sioux River and coinciding increased flow velocities in Dry Creek that caused erosion of its left and right bank and created a scour hole in the channel invert downstream of a sheet pile control structure in the creek. Dry Creek is protected by a right and left bank levee unit. The right bank levee provides protection to the City of Hawarden to the north and the left bank levee protects agricultural land to the south. The purpose of the PL 84-99 Emergency Levee Rehabilitation Program is to provide emergency assistance to levee districts and communities (project sponsors) in the form of levee repair and/or flood damage reduction as directed by Congress (33 U.S.C. 701n). The PL 84-99 Program is described in detail in ER 500-1-1 (Corps, 2001). The Hawarden, Iowa Dry Creek Flood Risk Reduction Project is a PL 84-99 project and its purpose is to restore the conditions of Dry Creek to pre-disaster conditions to repair the level of flood protection provided by both levees.