Floodplain Development Regulations Update - What & Why

What’s Happening Now?

SDCI is proposing to extend the interim floodplain development regulations a second time for an additional 6 months. The interim regulations are due to expire February 22. The proposed permanent floodplain regulations were appealed in July 2021 by the Port of Seattle and since then we have been working with the Port to resolve issues related to the appeal. 

A public hearing is scheduled for 2:00 p.m. on February 9 before the Land Use and Neighborhoods Committee. See the Get Involved page for additional information regarding the public hearing.

The proposed extension includes an amendment to the interim regulations. This proposed amendment is a correction to the interim regulations. The standard for the elevation for non-residential structures constructed above base flood elevation was unintentionally reduced from 2 feet to 1 foot in the interim regulations. This change was a code drafting error and has resulted in a lower standard of protection from flooding for 18 months. There was no intention to decrease this standard. The intent of the interim regulations was to keep the standard of 2 feet that existed in the regulations prior to the adoption of the interim regulations. Section 2 of the legislation contains amendments to SMC Section 25.06.110 to correct the error of the elevation standard for non-residential structures by changing the standard back to 2 feet.

The proposed interim floodplain development regulations extension are included on the Project Documents page. 

Project Benefits

Our Floodplain Development Regulations protect people, property, and the environment by regulating the development that occurs in the mapped floodplain and flood prone areas. The new permanent regulations will adopt FEMA's 2019 new Flood Insurance Rate Maps and Flood Insurance Study and will continue to regulate flood prone areas mapped by Seattle Public Utilities. Development regulations vary depending on the specific flood zone designations, characteristics of the property, and the nature of the development including first floor elevation. Below is a list of development regulations:

  1. The elevation that the first floor of a new structure must be built at to keep the first story above anticipated flood levels
  2. Structures must be engineered to withstand wind from anticipated storms
  3. Structures must be engineered to withstand flood waters should anticipated flood levels be exceeded

The End Result

The permanent Floodplain Development Regulations will meet FEMA's 2019 requirements.