By Steven Schauer, Deputy Executive Director, and King County Staff

The King County Flood Control District (KCFCD) has been working diligently since its creation in 2007 to safeguard our communities from flooding. The KCFCD, in collaboration with King County as service provider, has spearheaded over 370 capital projects aimed at mitigating the risk of levee and revetment failures. These projects, along with the operation and maintenance of over 500 flood protection facilities, cover 118 linear miles and approximately 800 acres of land crucial for flood mitigation.

While the KCFCD’s weekly blog typically shares information about new and ongoing projects, we occasionally shine a spotlight on a completed project that is quietly doing its job to safeguard our community against the threat of flooding. The project we’re covering this time is the Irwin Right Bank Revetment 2020 Repair Project along Issaquah Creek.

Restoring Safety and Stability: Irwin Right Bank Revetment 2020 Repair Project

In February 2020, heavy flooding along Issaquah Creek caused significant damage to the Irwin Right Bank Revetment, creating both safety concerns and increased flood risk for nearby residents and travelers along Issaquah-Hobart Road SE. The Irwin Right Bank Revetment 2020 Repair Project was successfully constructed in September 2022, restoring critical flood protection and ensuring continued safe access for residents and commuters. The project also incorporated large wood in its design to improve habitat for wildlife and fish, including threatened salmon species.

Why This Project Was Needed

The Irwin Right Bank Revetment has played an important role in flood risk reduction for decades, safeguarding Issaquah-Hobart Road SE, which is a heavily traveled roadway and sole access route to three private properties. Damage to the revetment first began in the 1980s, worsening after the November 1986 flood, and again in subsequent flood events.

When the February 2020 flood struck, the structure lost toe and bank rock along a 125-foot stretch. The result was an over-steepened bank, exposed fill material, and missing large rock at critical points near a private bridge and upstream along the road. Without timely repairs, the damage risked spreading further, threatening both public infrastructure and private property access.

Protecting Roads, Bridges, and Communities

The KCFCD, working through its service provider King County, moved quickly to evaluate repair alternatives and implement a durable solution. Construction began in late July 2022  and was completed by September with minimal disruption to the surrounding community.

The repairs restored the stability of the revetment, reinforced the bank with large rock, and reduced the risk of potential failure. These improvements protect:

• Issaquah-Hobart Road SE, a major travel corridor.
• A private bridge, providing the only access to one property.
• A private road, serving two additional residences.

By completing this project, the KCFCD has safeguarded vital infrastructure and ensured peace of mind for local residents who rely on these access points every day.

Community Engagement and Equity

Throughout the project, the KCFCD and King County emphasized clear, consistent communication with residents, landowners, and tribes. Incorporating equity and social justice practices into outreach efforts ensured that residents and interested parties were heard, informed, and respected at every stage.

Neighbors near the project have long been invested in the safety of this revetment, and their feedback and observations helped inform the repair approach.

Looking Ahead

While this project focused on a straightforward repair, its completion underscores a broader commitment: protecting King County residents, roads, and infrastructure from the risks of flooding. Each project, whether large-scale levee setbacks or targeted revetment repairs, represents a step toward a safer, more resilient future.

The Irwin Right Bank Revetment Repair is a reminder of how proactive flood risk reduction measures can prevent future crises, reduce risks, and sustain communities for generations to come.