Sammamish council reviews Sahali Way corridor study, weighs two high-cost alternatives and slope mitigation

The Sammamish City Council heard technical findings and cost estimates Feb. 11 for the Sahali Way corridor study, a master-planning effort that covers the roadway from Northeast Eighth Street south to State Route 202 and will be carried to public engagement this spring.

The city’s project team and consultants described three geotechnical zones with past landslides and seven distinct slide scars along the corridor, recommended monitoring and targeted instrumentation, and asked the council whether to advance alternative 7 or alternative 8 as one of the public-facing options. “This is what we're asking council for. Do you like alternative 7 or 8?” said Jed Ireland, senior project engineer and the project manager for the Department of Public Works.

Why it matters: the corridor plan will set a long-term framework for walking, biking and traffic safety and guide later design and construction. It also intersects urgent stability issues: consultants said some slope areas are close to the existing fog line and will probably require mitigation within a 10–25 year horizon even if the city takes no immediate capital action.

Geotechnical findings and monitoring

Donald Huling of HWA Geosciences, the project geotechnical lead, divided the corridor into three geotechnical zones. He said the…