Working with CREST and project stakeholders and landowners, W2r has delivered several floodplain restoration projects from design to construction on and adjacent to Sauvie Island over the last several years.
Sauvie Island offers floodplain refuge habitat just downstream of the urban waterfront corridors on the Columbia and Willamette Rivers, but much of this habitat has been disconnected from tidal influence and is dominated by reed canary grass. Restoration designs will benefit not only salmonids, but also beaver, waterfowl, reptiles, and amphibians.
Project sites include four on Sauvie Island: Crane, Domeyer, Willow Bar, and Flight’s End; and two at Burlington Bottoms (along the Multnomah Channel): Enyart and Palensky.
Our services included geomorphic assessments, 2D unsteady hydrodynamic modeling, alternatives analysis, final design plans, construction specifications, FEMA No Rise analysis/certification, cost estimates, stakeholder outreach support, and construction oversight.
2D modeling of the Palensky site (at the McCarthy Creek confluence with Multnomah Channel) simulated the effect of beaver dams and beaver dam analogues across the floodplain to preserve turtle and frog habitat. To accurately simulate floodplain inundation and infiltration, we developed innovative techniques to model infiltration losses during recession of the spring freshet.
Client
Columbia River Estuary Study taskforce
Keywords
Multi-species habitat enhancement, fish passage, culvert replacement, bridge construction, hydrologic and hydraulic modeling, FEMA No Rise analysis/certification
