Upper White Pine Floodplain Reconnection Presentation to PRCC Nov. 13, 2014 Heres what we heard 1.Why not re-connect the historic channel? 2.Does this design provide the highest biological benefit for the cost? Could you just breach the levee and let the re-located channel just form its own path? Presentation Overview 1.Why not re-connect the historic channel? 2.Soils Data 3.Modeling Results 4.Levee breach and let it go 5.Revised Design Concept 6.Next Steps/Discussion Historic Channel 190 long culvert or 240 long bridge 2 perforations through railway floodplain/CMZ Soil Sampling Channel profile with soil pit data Preliminary 2D Modeling Results - Inundation 2 year 10 year 50 year100 year Preliminary 2D Modeling Results - Velocity 2 year 10 year 50 year100 year Why not breach levee and let it go? 1.Uncertainty with channel formation through project area 2.Downstream impacts to habitat and aquatic organisms 3.Downstream impacts to infrastructure Uncertainty with channel formation through project area Sand substrate will result in high erosion rates with unpredictable results Undesirable impacts could include: Re-occupation of existing channel Re-creation of new incised channel Channel formation straight through powerline corridor Downstream impacts to habitat and aquatic organisms Discharge of 30,000 cu yds or more of material, much of it fines Sediment impacts could be chronic and long-lasting, with detrimental channel instability persisting for years WDFW comments Lack good data on current sediment levels/issues Egg to fry studies to determine if limiting factor Concern about introduction of more fine sediment USFWS comments 303d Listed for temperature Downstream impacts to infrastructure 30,000+ cy Material deposition channel response Rapid lateral erosion Channel avulsions Potential impact to downstream infrastructure Highway 2, Railroad, CPUD & BPA powerlines, private properties Rate of channel change already high due to conversion of project area to a Transport Reach in late 1950s/early 1960s Revised Design Concept Revised Design Concept Why? Not Overly Engineered Similar Floodplain Connection Proposed Bank Treatments FESLs on outside bends Coarse and fine material Plant between & through Wood At toe of FESLs On face of banks Burial and piling anchoring Objective = reduce or eliminate ferrous anchoring 10 year 2 year old FESLs at Tyee Next Steps Project timeline Critical paths 1.NEPA December 60% design information to USFS February EA and draft decision notice 2.Powerline Re-location 2015 December Construction MOU in place January draft bid documents for poles February bid for poles March pole engineering design April order poles for August delivery September install poles 3.Restoration Funding Questions and Discussion 1.Format/process for funding request? 2.Liason? Cost and Evaluation of Alternatives Levee removal only 30% Design 2 meanders Current concept 3 meanders 4 Meander concept Least expensive Most expensive Biological Benefit Ranked 1 4 Cost