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Staff Contacts
Puget Sound shoreline next to the West Point Treatment Plant, Seattle

Barton CSO Control Project

Project area

King County is designing green stormwater infrastructure (GSI) to control combined sewer overflows (CSOs) in the Barton basin. The GSI project will consist of bioretention swales (engineered rain gardens) between sidewalks and curbs in the Sunrise Heights and Westwood neighborhoods in West Seattle. Street runoff will flow into the bioswales during rain storms. The stormwater will then be conveyed deep underground for infiltration and eventual return to the local aquifer.

Preliminary design locations

 

To view preliminary design locations, look at the breakout area sessions map and then click on the detailed area maps.
Source: Handout from March 28 and 30 public meetings.

Break Out Sessions for Areas 1-4 for site-specific discussion, March 28 and 31 public meetings, 2012

 

 

Area 1 Detail Map (PDF)

 

 

Area 2 Detail Map (PDF)

 

 

Area 3 Detail Map (PDF)

 

 

Area 4 Detail Map (PDF)

 

CurbBulb
Example of curb bulb

Example of GSI in High Point, West Seattle
High Point during 25-year storm event

GSI_PortTownsend
Port Townsend after storm event 

Bioretention: Planting Overview
Bioretention: Planting Overview, Slide 34 (PDF) from the March 2012 community meeting. View entire presentation (PDF). 

Project elements

GSI uses soils and vegetation to capture, infiltrate, and reuse stormwater. In the Barton basin, bioswales will also be designed with underdrains to convey water to deep infiltration wells at various locations throughout the project area. The deep infiltration wells are designed to convey stormwater below the low permeability glacial till soil layer to a soil layer that is excellent for infiltration. Community input is helping inform design of the bioswales and will be used to help select plants for individual swales.

  • Existing planting strips landscaped and planted for stormwater infiltration
  • Curb bulbs widening planting strips on some streets
  • Curb cuts allowing street runoff to enter and exit bioswales
  • Specially amended soils to quickly infiltrate stormwater
  • Vegetation designed to remove stormwater pollutants
  • Horizontal underdrains beneath swales to convey water to infiltration wells
  • Deep infiltration wells at southern end of most blocks to move water below glacial till for infiltration and eventual return to the local aquifer

Community input

Working with the community during the planning and early design phases of the Barton CSO Control Project, King County has identified neighborhood concerns. The project team will work closely with the community throughout design and construction.

  • Parking/traffic
  • Disability access
  • Swale crossing locations and materials
  • Existing trees and plants
  • Maintenance
  • Utilities
  • Landscaping plans
  • Drainage
  • Length of construction and impacts on residents

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