Lower Snoqualmie Channel Migration Zone Study and Map
Lower Snoqualmie Channel Migration Zone Study and Map
The King County Flood Control District and King County are studying channel migration, a type of flood hazard, on the lower Snoqualmie River. Use the tabs above to learn about the study process, draft channel migration zone map, and sign up for updates. Visit Estudio y mapa de la zona de migración del canal del Bajo Snoqualmie to view this page in Spanish.
Interpretation and translation services are available at no cost to you. If you need them, please contact Andrew Gendaszek at agendaszek@kingcounty.gov or 206-477-8926.
Hay servicios de interpretación y traducción a su disposición sin costo alguno. Si los necesita, póngase en contacto con nosotros mandando un correo electrónico a agendaszek@kingcounty.gov o llamando a 206-477-8926.
Welcome
Flood hazards along the lower Snoqualmie River have historically caused significant damage to nearby homes, farms, business, and public infrastructure. Flood hazards include flooding by inundation—when the river rises and overflows its banks—as well as channel migration. In response, the King County Flood Control District and King County, as service provider, are working to improve flood resilience.
King County is developing the first channel migration zone map of the lower Snoqualmie River. King County has previously mapped channel migration zones in rivers across King County, including the Tolt River, Raging River, and Snoqualmie River upstream of Snoqualmie Falls. Channel migration zone maps identify where a river or creek could move in the future. The maps help people make decisions that keep themselves, their families, and their properties safe.
The maps will also provide local governments with accurate data to use in development and permitting decisions.
Stay in touch
To receive updates on this study, sign up for the project email list.
What is channel migration?
Channel migration is a natural, but potentially dangerous process. River channels can move across their floodplains, either due to gradual bank erosion or when a river jumps course. The process can cause riverbanks to recede or move completely and can trigger landslides. It can also cause wood and debris to move, and sediment deposits to shift and build up. The process can threaten homes, roads, and other infrastructure, and change flooding patterns.
Lower Snoqualmie River Channel Migration Zone Study Area
The study area for the Lower Snoqualmie River Channel Migration Zone Study and Map extends 33 miles from the base of Snoqualmie Falls downstream to the King-Snohomish County line. The study area includes the cities of Carnation and Duvall, the unincorporated community of Fall City, and rural unincorporated King County.
