Swift Company LLC
Sound Transit Design/Build Project
Client: Kiewit
Civil Engineering/Architecture: Parsons
Status: Under Construction
The Federal Way Link Extension is a planned Sound Transit Link light rail extension that will travel 7.8 miles south from Sea-Tac Airport to Federal Way, along the west side of Interstate 5, including three new stations. The system will serve roughly 30,000 people daily by 2026, supporting growth management objectives and addressing issues of access to housing and jobs in the Puget Sound Basin. The transit corridor of aerial and at-grade light rail guideway requires mass restoration re-stitching of the urban forest. With 73 acres being revegetated in Puget Sound Lowland Forest, existing trees salvaged for reuse, and vegetated buffer for adjacent neighbors, significant contributions are being made to restore the lost canopy from construction and offset carbon impacts from the light rail project. Swift Company’s scope is the design and documentation of corridor restoration which will reestablish the regional lowland forest landscape, and the design of the station areas for three new stations - community hubs that will stitch together transit-oriented development with generous public open spaces designed to bolster the urban forest and provide new places for people.
The project uses ProjectWise for document sharing and management. The project is separated into 4 general areas: Corridor-Wide, Kent/Des Moines Station, Star Lake Station, and Federal Way Transit Center Station. Each discipline has at least one corresponding design package for each area. Each design package consists of at least 4 submittals: 30%, 60%, 90-100%, and Issued For Construction (IFC). After the IFC, there have been 707 design changes issued by far, and Swift Company has been involved in 180 of them. Each submittal has a review process that includes several rounds of commenting and comments resolution to answer questions, solve design challenges, and coordinate between disciplines.
The Landscape scope for the corridor restoration includes all the areas that will be impacted by the construction of the light rail. The project site was evaluated and different plant mixes have been proposed based on the different hydrological characteristics of the site. The tree/shrub planting are divided into 3 categories based on hydrological features: xeric, mesic, and hydric. They are also differentiated by plant material height. The tall plant mixes include tall trees, short-stature trees (understory of the tall trees), shrubs, and groundcover. The low plant mixes include short-stature trees, shrubs, and groundcover. Some low plant mixes could also be shrub-only. Tall plant mixes are used as much as possible to maximize the restoration volume. Areas that are immediately adjacent to the light rail have to use low plant mixes for a clearance requirement. Areas that will be further impacted by future development are planted with hydroseed only.
In the project-impacted area, 12 acres previously developed area will be converted to pervious landscape area, which makes the total post-construction landscape area 73 acres.
