DESCRIPTION
This multi-phased project is focused on restoring tidal connectivity and fish passage as well as addressing stormwater drainage issues associated with an 18-acre brackish lagoon and freshwater marsh system in Greenbank, WA. The project site, most of which is owned by Greenbank Beach and Boat Club (GBBC), is the relic of a larger tidal marsh that occupied the area prior to settlement in the 19th century. In this second phase, GBBC, with support from Whidbey Island Conservation District (WICD), will use the results of WICD's 2013 feasibility study and SRFB grant No. 15-1072 "Greenbank Marsh Restoration Issues Assessment" (Phase 1) to develop an engineering design and permit applications for the selected conceptual restoration alternative. The primary tasks of this proposed second phase will be to hire geotechnical and coastal engineering consultants to support WICD's completion of the permit level (90%) engineering design and to continue stakeholder outreach and consultation activities. GBBC will be responsible for project management and public consultation. GBBC will contract with WICD to do fiscal administration, manage engineering efforts to prepare the design, and prepare permit applications for the subsequent construction phase.
The project completed engineering, hydrogeology and stakeholder outreach activities to advance the project objectives. Based on consultant inputs on hydraulic engineering, coastal geomorphology and hydrogeology field investigation and modeling, WICD prepared preliminary design plans. WICD and GBBC presented the plans at a pre-application permitting meeting with Island County. Based on input from the county, the project hired a consultant to prepare biological assessment studies to support final permitting. GBBC and WICD also convened an ad hoc group of interested local stakeholders to discuss project plans and how to integrate them with community interests in improving local drainage and flooding conditions. This Greenbank Marsh Working Group met approximately quarterly and filled the role as a stakeholder steering committee for project work.
Based on input from the county and the Working Group, GBBC obtained a budget and scope amendment in summer 2019 to complete additional detailed hydraulic engineering and hydrogeology modeling to address drainage and groundwater issues that were identified in the initial assessments. Potential impact on the shallow water table related to restoring the full tidal prism into the marsh turned out to be the critical technical problem. To address this, a consultant installed additional groundwater wells, completed a pump test and refined the initial groundwater model. The updated modeling results indicated that restoration of the tidal prism to the marsh would raise and increase the salinity of the shallow water table under adjacent properties. Subsequent engineering work showed that the cost to mitigate for the impacts made them infeasible for GBBC to commit to. Accordingly, WICD and GBBC’s board decided that it was impractical to pursue construction of the project design at this time. Details of how this decision was made are documented in the project completion report.
PCSRF FY14 funds were spent within the appropriate grant period. This project extended beyond the 2014 award date, but all PCSRF FY14 funds were spent in full before the expiration date.
