Floodplain Management & Regulations

Blaine County has a robust permitting program to ensure that all development within the waterways and floodplains complies with our No Adverse Impact Policy. No adverse impact floodplain management takes place when the actions of one property owner shall not adversely affect the rights of other property owners or the County's NFIP eligibility. Adverse impacts include increased flood peaks, flood stage, flood velocity, erosion and sedimentation, or decreased water quality or quality of riparian habitat.

To minimize damage to structures during flood events, the County requires all new construction in the floodplain to be anchored against movement by floodwaters, resistant to flood forces, constructed with flood-resistant materials, and flood- proofed or elevated. The first floor of living space, as well as all mechanical and services, must be elevated at least two feet above the elevation of the mapped flood level. 

Before You Act

All development within the floodplain, including but not limited to grading, cut and fill, installation of riprap, and other bank stabilization techniques, requires review from this office. County staff is available to undertake site visits, if requested, to review flood, riparian and setback issues. Contact the County Land Use Department at 208-788-5570 or view Blaine County's floodplain and riparian regulations, prior to undertaking any activity within the floodplain. For all permit applications, visit our Land Use Applications page.