Draft environmental impact statement for Centralia flood damage reduction project

Proposed Action: Seven alternatives were proposed to provide 100-year flood protection to the cities of Centralia and Chehalis, Washington, while providing potential restoration opportunities within the project area.

Responsible Agencies: U.S. Army Corps of Engineers
Lead Agency: U.S. Army Corps of Engineers

Abstract

The cities of Centralia and Chehalis, Washington have been subject to flooding for many years. This flooding has caused extensive damage to private and public property and caused periodic closure of critical transportation routes resulting in significant economic losses. The closure of critical transportation routes also disrupts emergency response teams and adversely impacts public safety. In addition, stream habitat functions of the Chehalis River and its tributaries have been damaged in the past due to development throughout much of the Chehalis Basin. This has resulted in the diminishment of the remaining habitat to adequately support sustainable fish and wildlife resources.

The loss of wetlands, riparian areas, and back channels has also contributed to increased flooding in the area. The proposed preferred alternative will provide the cities 100-year flood protection and provide habitat enhancement opportunities for fish and wildlife. With set back levees, there will be opportunities for the river to overflow its banks and potentially restore riparian habitat along its banks while providing flood reduction. The Skookumchuck dam modifications will allow flood water storage up to 492 feet or 20,000 acre feet of water behind the dam for a period not to exceed five days. This will provide some flood reduction along the Skookumchuck River. After modifications are completed to the dam, a re-operation plan will call for a maximum flow at Pear Street not to exceed 5,000 cubic feet per second. This can only occur on events under the normal two-year event because, with events two years and over, the tributaries will augment the river flow resulting in a loss of flow controls at Pearl Street. The greatest protection from dam modifications will occur between the 50- and 100-year events. There is expected to be an adverse impact on 40 acres of wetlands resulting from levee construction and no major wetland impacts from dam modifications. The Corps has committed to further studies to investigate stream bed-load and sediment movement on the Skookumchuck River.

Note: Official closing date for the receipt of comments is September 19, 2002. This report is also available on the web site at: http//www.nws.usace.army.mil/index.cfm

All official report copies for the Centralia Flood Damage Reduction Project are available here.

For an online viewable version of the Draft Environmental Impact Statement:

• Centralia Flood Damage Reduction Project Executive Summary.
• Centralia Flood Damage Reduction Project Draft EIS Chapter 1
• Centralia Flood Damage Reduction Project Draft EIS Chapter 2 .
• Centralia Flood Damage Reduction Project Draft EIS Chapter 3 .
• Centralia Flood Damage Reduction Project Draft EIS Chapter 4 .
• Centralia Flood Damage Reduction Project Draft EIS Chapter 5 .
• Centralia Flood Damage Reduction Project Draft EIS Chapter 6
• Centralia Flood Damage Reduction Project Draft EIS Recipients and preparers
• Centralia Flood Damage Reduction Project References
• Centralia Flood Damage Reduction Project Glossary of acronyms, abbreviations and terms .

Vision Statement

Ecosystem Restoration and Mitigation Working Group for the Centralia/Chehalis Flood Damage Reduction Study

In response to an inquiry from the Chehalis River Council to the Corps of Engineers, we have been added to a distribtuion list for materials related to the Ecosystem Restoration and Mitigation Working Group.

This material is presented for your information as it relates to the ongoing developments surrounding flooding in the Centralia, Chehalis and greater Chehalis watershed.

The US Army Corps of Engineers and Lewis County are currently preparing a General Reevaluation Report and Environmental Impact Statement (GRR/EIS) in relation to efforts to reduce flood water damages to the cities, highway system and metropolitan area of Centralia and Chehalis. The Centralia, Washington GRR/EIS Restoration/Mitigation Working Group (working group) is envisioned to be a group of agency and Tribal representatives interested in the health of the river and the riparian ecosystems in the Chehalis River watershed. The primary purpose to assemble the working group is to provide the opportunity for input and ideas from interested agencies into the plans, strategies, methods and locations for preferred habitat restoration and habitat mitigation measures in relation to each of the alternatives being considered by the Corps and Lewis County.

1. Working Group Vision Statement
2. Planning Strategies for the Centralia/Chehalis Flood Damage Reduction Study
3. Initial meeting minutes 1st Meeting
4. Field visit memo
5. September 8 meeting minutes 2nd Meeting
6. Initial Pre-Draft Restoration Plan Report
7. October 20 meeting minutes 3rd Meeting
8. Dec. 20, 2000 The Chehalis Flood Hazard Reduction Study minutes for the 4th working group meeting are available.
9. Dec. 20, 2000 The Chehalis Flood Hazard Reduction Study minutes for the 5th working group meeting are available.
10. Dec. 20, 2000 A Memo for the record identifies the action items that surfaced from the meeting with the resource agencies dealing with the Chehalis Flood Hazard Reduction Study program.
11. Jan. 30, 2001 The January 25th meeting (number 6) minutes are not available.
12. May. 18, 2001 Thanks to the Corps of Engineers for the minutes of the April 23 (7th) Ecosystem Mitigation Planning meeting.
13. Jun. 18, 2001 The Corps has released a evaluation panel procedures document dated June 21, 2001.
14. Jun. 18, 2001 We've received the Corps of Engineers minutes for the 8th working group meeting May 31, 2001