Description -- Phase 1 (levee base improvement) involves expanding the inside width of the existing levee without increasing levee elevation or causing any measurable adverse impact or effect. Phase 1 will improve the base of the levee and result in an additional 32 acre feet of fill inside the existing levee. The fill required for this levee project is less than one percent of the overall airport property volume and a much smaller percentage of the total flood volume in the twin cities area. Since the fill is behind the levee it will not block flows and will not create any measurable increase in upstream or downstream flooding based on the HEC-RAS hydraulic model for the basin. Project (Phase 1) is planned to be completed Summer 2014.
Flood Hazard Reduction Benefits -- Completion of Phase 1 at the Airport will provide immediate and critical additional flood protection to the airport facility and to the most active complex of retail stores in Lewis County which generate approximately $550,000 per day in sales income with significant accompanying tax revenue. This improvement will provide a level of protection against flooding up to events similar to the one experienced in 2007 which was the fourth highest flood of record at the Centralia Mellen Street gauge.
Project Status -- Phase 1A -- On-track, On-schedule. Phase 1B -- Design/Construction Incorporated into WSDOT’s I-5 Flood Protection Project..
Project Schedule -- Phase 1A and Phase 1B are described as follows:
Phase 1A: Improvements not affecting jurisdictional drainage ditch wetlands inside the levee:
DONE -- July 2014 -- Phase 1A complete and finished.
June 2014 -- Construction began July 22, 2013. To date, approximately 80% of work is complete. Levee fill material (Common Borrow) is moisture sensitive and difficult to place during wet weather. Project has experienced several unworkable days due to rain showers and wet sub-grade following rain days. Current and anticipated weather requires a construction shutdown until conditions improve for common borrow placement. The majority of the project is nearly complete with 36,000 CY of fill material placed (41,000 CY originally planned for Phase 1A). Due to the heavy truck/construction equipment movements required on the moisture sensitive common borrow fill material, levee construction will likely resume by July 2014 when conditions are dry and warm. There are 25 working days remaining for the completion of Phase IA construction.
DONE -- 7/22/2013 -- Construction Start July 22, 2013.
DONE -- 6/03/2013 -- Award Contract. All permits approved and Contract awarded to Sterling Breen Construction (Chehalis, WA) for their low bid of $910,042.50 (Engineer’s Estimate was $903,365.00).
DONE -- 5/07/2013 -- Open contractor bids.
DONE -- 4/15/2013 -- Advertise for contractor bids.
DONE -- March 2013 – All environmental permit applications submitted.
Phase 1B: Improvements associated within Corps jurisdiction:
Airport Levee Widening within the Corps jurisdiction will be accomplished by WSDOT during their future I-5 Flood Protection Project.
Typical levee base widening construction.
Engineered design and drawings.
Base-widening cross-section drawings.
Preparation for silt fence installation.
Beginning base widening at the south end of the levee.