The West Duwamish Combined Sewer Overflow (CSO) Control Project will control CSOs for King County’s West Michigan and Terminal-115 basins to the Washington State regulatory requirement of one-event per year on a rolling 20-year average. As Design Team Manager, RKI led the GSI alternatives analysis to identify and compare various combinations of grey and green technologies to achieve the control strategy and help protect the Duwamish River and Puget Sound.

Kitsap County Public Works (KCPW) developed a stormwater retrofit plan for East Bremerton and East Port Orchard to identify, prioritize and construct stormwater retrofit projects that address water quality and drainage problems. Both Green Stormwater Solutions and conventional stormwater techniques are used. The end result is a suite of management planning tools, including a prioritized list of projects and conceptual designs to support KCPW’s Capital Facility Plan and assist with obtaining grant funding for final design and construction of priority projects.

King County Wastewater Treatment Division (WTD) proposes to install Green Stormwater Infrastructure (GSI) facilities to the maximum extent practicable to reduce the gray infrastructure demands needed for full Combined Sewer Overflow (CSO) control at the University Regulator Station Overflow. RKI is serving as the Interagency Permitting Lead, responsible for planning and obtaining SDOT Street Improvement Permits and other required construction permits.

This project installed and will monitor permeable pavement for durability, water quality (influent and effluent), and infiltration rates. RKI assisted the City of Spokane with research on successful monitoring practices and lessons learned by other jurisdictions and provided design review and recommendations for final design, construction, monitoring, operation and maintenance.

As part of its Plan to Protect Seattle’s Waterways, SPU committed to constructing green and/or gray infrastructure that will bring the Vine basin into compliance with Combined Sewer Overflow (CSO) regulatory requirements by the end of 2025. Serving as GSI Lead, RKI helped SPU develop and evaluate GSI options and select the preferred option to be advanced to final design and construction.

SPU estimates a Combined Sewer Overflow (CSO) control volume of approximately 6 million gallons is needed to meet NDPES CSO control regulations for two uncontrolled basins in the Ballard neighborhood. While at a previous firm, Robin served as Project Manager and Lead Engineer through Options Analysis and final construction design of 17 blocks of residential roadway GSI for CSO control. Following construction in 2016, RKI was retained to develop the project-specific standard operating procedures and operation and maintenance manual. This project won the inaugural 2017 Pacific Northwest Clean Water Association Innovative Stormwater Project award.