Flood & Floodplain Information

Portions of the City of Scappoose are subject to periodic flooding. The City has close to 173 acres of floodplain and nearly 245 individual parcels that are partially or entirely located within the floodplain. The flooding occurs when watersheds high in the hills collect water over a broad area and the waters flow down drainage ways to Scappoose Creek, which continues the discharge flowing toward the Multnomah Channel and the Columbia River. The Multnomah Channel affects flood potential through tidal action and siltation. Tidal action slows the discharge of water from the Columbia River and its tributaries while siltation reduces the volume of water handled by the tributaries. Ongoing development within the City and in Columbia County displaces natural areas that have historically functioned as flood storage.

Be sure to check the city maps page for Floodplain and Wetlands and Riparian; City Maps | City of Scappoose Oregon

Columbia County also provides maps on their website;   Columbia County Web Map (columbiacountymaps.com)

Or visit FEMA FLOODMAPS;  https://www.fema.gov/flood-maps

Link to the Scappoose Drainage Improvement Company (SDIC);  (public corporation funded by tax assessments paid by landowners within the boundaries protected by the levee known as The Dike.) www.scappoose.gov/engineering/page/scappoose-drainage-improvement-company

Link to the Scappoose Bay Watershed Council;  http://www.scappoosebay-wc.org/

 

REMODELING A STRUCTURE:

There are special considerations when remodeling a structure in the floodplain. If the cost of the renovation/repair is equal to or more than 50% of the market value of the house (not including the land value) then it is considered a substantial improvement and the house must be brought up to current floodplain standards, including potentially raising the entire house one foot above the base flood elevation, etc.  Review the full definition/description within the FEMA link below; https://www.fema.gov/node/405414

Additional City of Scappoose Sensitive Land Use permits would apply to all development in a floodplain, wetlands as well as riparian; www.scappoose.gov/planning/page/sensitive-lands-development-application