Here comes the water!

Engineering: Tetra Tech Inc.
Landscape Architecture: J.A. Brennan

The Riverview Park Ecosystem Restoration Project reached a milestone in October when the channel inlet and outlet coffer dams were removed, allowing water to flow for the first time though the new side channel!  Crews raced against the clock to finish in-water work before migrating salmon entered this reach of the Green River.  They  excavated to finish grade, placed streambed gravel , rock slope protection, bioengineered soil lifts,  and anchored in-stream woody debris.   Careful monitoring ensured that salmon were not impacted by construction activities.

Since then, crews have hydroseeded the site, and now are planting more than 7,000 native trees, shrubs and ferns and more than 2,000 native emergent plants.   We look forward to seeing the plants all installed;  then, site will really begin to look like a natural channel….irresistible to the fish.   So, stay tuned for more updates!

Aesthetic Enhancements for a City of Kent Flood Wall

Typical concrete floodwall? 

Or integration of art that signifies place? 

These were the choices the City of Kent had when considering improvements to the Boeing Levee at Three Friends Fishing Hole Park.  As the city neared completion of flood wall design for the Boeing Levee, inventive thinkers proposed adding art to the wall’s face along the span of the park.

Six weeks of design time

We were brought into the project as the structural engineering design of the flood-wall levees was nearing completion; a short time remained until the project would be going out to bid.  The short time-frame required quick thinking and an organized process.  Our design team’s familiarity with designing aesthetic treatments for walls and bridges allowed us to go from zero to fully developed construction drawings for wall textures and surface treatments in the allotted time.

An initial brainstorming session with the client led our designers to develop two alternative themes.  A nature-based Green River Ecology theme could honor the ecological story of the river.  The second potential theme employed the history and geomorphology of the Green River Valley, from pristine river to agricultural and then modern-day industrial corridor.  In either case, a part of the river’s story would be told for passers-by on the adjacent bike trail, park visitors, and adjacent industrial landowners.

Working out the details

Multiple material and treatment possibilities were discussed for the expression of the considered themes on the wall face.  Options included

  • Standard and custom formliners, which would create bas relief sculptural elements integral to the wall face
  • Sandblasted aggregate reveal
  • Sawcut patterns
  • Glass fiber reinforced concrete
  • Green wall

In the end, cost was a major consideration.  Research made it clear that the best way forward would be with custom formliners.

Ecological Story

With cost information and design alternative sketches in hand, our client opted to tell the ecological story.  Our designers got to work developing a story board with appropriate images.  Meetings with the client further refined the initial choices and allowed us to move forward with detail design of the custom formliners required to make this vision a reality.  We generated CAD drawings that went into the bid package on time and on budget.

The final design celebrates the Green River with shapes, textures, and colors that are stylized representations of the life forms within the river system.  Recognizable images were selected: salmon, salamander, maple leaf, redtwig dogwood, and blue heron.

Custom formliner panels are 3’x3’, which are easily multiplied to cover the typical wall heights (front and back). The panels depict the wildlife/vegetation in detail surrounded with a subtle background texture.  Panels are designed so that they can be repeated in differing sequences and orientations, interspersed with standard formliner panels, thereby providing a rich and varying experience as one moves along the length of the wall.

In the end, our understanding of the aesthetic design process helped guide the client through a quick decision making process and resulted in a design that tells a place-sensitive story, turns a wall into art and enhances the park experience for all visitors.

The $2.65 million levee project is scheduled to begin construction mid August.

More information: Work to begin soon in Kent on $2.65 million levee project 

Riverview Park Ecosystem Restoration Update

J.A. Brennan is part of a consultant team working with the City of Kent and the U.S. Army Corps of Engineers to create a habitat enhancement channel on the Green River at Riverview Park.  In this photo, the 25’-deep side channel excavation is nearly complete.

The contractor, Performance Systems, Inc., is busily working to complete the excavation and shore protection.  Excavators, rollers and dump trucks criss-cross the site moving and grading soil and fill materials.

Looking up-channel, a crane installs coffer dam piles.  In the foreground, soil lifts – soil wrapped in geotextile fabric – are installed.  The lifts will be planted with both container plants and live stakes.  Tetra Tech, Inc., the prime consultant and project engineer, is providing a variety of bio-engineering solutions to create a naturalistic and protected channel bank.

The foundation of the channel inlet constructed log jam structure is in place.  This sturdy bio-engineering solution by Tetra Tech, Inc. is the first line of defense  against potentially high-velocity, high-volume storm flows surging down the Green River.  Live stake plants will provide further erosion control, and help naturalize the constructed log jam.

The approximately 125’ long pedestrian bridge is in place.  Riverview Park visitors will gain an exceptional view of the new side channel, and access to the island (on the right) between the channel and the Green River.  A loop path around the island will meander through meadow and a mature Cottonwood canopy.  Native plant restoration along the Green River banks will enhance the existing native riparian corridor.

Looking at the channel outlet, you can see the coffer dam.  An excavator-operator continues to dig out this area to reach channel bottom grades.  PSI continuously dewaters the area behind the coffer dam to keep working conditions nice and dry.

For more information see the Seattle District US Army Corps of Engineers’ webpage.

Riverview Park Ecosystem Restoration

J.A. Brennan recently completed multiple illustrative graphics, which were used in the project ground-breaking ceremony, and in other public outreach and informational efforts.

J.A. Brennan is a member of the consultant team that worked with the City of Kent and the U.S. Army Corps of Engineers (Corps) to design a Habitat Enhancement Channel at Riverview Park.  This newly created side channel is part of a pilot project by the Corps to restore side channel and low-flow environments along the Green River for the benefit of spawning salmon and steelhead.  Previously, J.A. Brennan developed the master plan for the park.  For this project we were able to provide valuable insights to the project with our site experience and park design expertise, which helped coordinate the City’s park plans with Corps habitat objectives.

J.A. Brennan developed contract documents for trail design, planting and irrigation of approximately four acres of restoration area, including native aquatic, riparian and upland environments.  Wooded trails and a new 200-foot long bridge, will provide public access to this restoration project, and educational signage and viewpoints will further enhance the visitor’s experience and provide information about the Green River ecosystem.

Construction of the new side channel at Riverview Park in Kent is underway! The new side channel will offer rearing habitat for endangered salmon species including Chinook, steelhead and bull trout. The side channel is a partnership of the U.S. Army Corps of Engineers , the city of Kent, the Water Resource Inventory Area 9 (WRIA 9) Ecosystem Forum, the Washington State Salmon Recovery Funding Board and the King Conservation District.