Floodplain development permits regulate construction and other activities within Boulder County’s regulated floodplains. These permits ensure that proposed projects meet floodplain standards, protect public safety, and comply with county and federal floodplain regulations. Learn more on the Building, Safety and Inspection homepage.
Floodplain Development Permits
General Floodplain Development Permits (FDP)
The Boulder County Floodplain Management Program issues General Floodplain Development Permits (FDP) in accordance with Section 4-404.1 of the Boulder County Land Use Code:
General FDPs cover projects and uses in the FO District that have been determined by the Floodplain Management Program to meet the applicable criteria set forth in Section 4-404.1(B) of the Boulder County Land Use Code, which, among other criteria, includes those projects and uses that have been determined to have minimal or no impact on flood hazards.
General FDPs allow certain projects and uses to take place without the need for an Individual Floodplain Development Permit. Some projects permitted by the General FDP still require notification of the Floodplain Management Program as described below.
Notification submittals should be submitted to floodplainadmin@bouldercounty.gov and must include the following information:
- Project description, including materials to be used and a narrative on the expected impact to the channel and Floodplain
- Location description with accompanying location map
- Site Plan
Boulder County will respond in writing no later than 14 days following submittal of notification and confirm whether or not a project is covered under the General FDPs, whether more information is required in order to make a determination, or whether the project is NOT covered by the General FDPs and submittal of an application for an Individual FDP is required.
Individual Floodplain Development Permit
An individual floodplain development permit is required for all development in the floodplain that is not covered under a General Floodplain Development Permit.
Floodplain Development Permits must be obtained from the Boulder County Floodplain Management Program before the start of construction.
- View Individual Floodplain Development Permit Fees
- View Individual Floodplain Development Permit Application
Floodway Review
A Boulder County Floodway Review is required for any project in a county-administered floodway that results in 100-year surface elevation increases between 0.00 and 0.5 foot (existing vs. proposed conditions). For increases in a county-administered floodway that are greater that 0.5 foot, an approved Conditional Letter of Map Revision (CLOMR) is required prior to permitting. In FEMA-administered floodways, a CLOMR is required for projects that result in any increase (greater than 0.00) in 100-year water surface elevations prior to permitting.
Buildings
For information on requirements for new buildings or improvements, review the Individual Floodplain Development Permit (FDP) Checklist for Buildings.
Agricultural Structures in the Floodplain
In May 2023, to comply with FEMA policy, the Board of County Commissioners approved updates to the Land Use Code regarding agricultural structures in the floodplain.
New or Substantially Improved agricultural structures may only be built at grade if an Administrative Variance is granted and the structure:
- Has low damage potential and cost of recovery with respect to construction materials, location within the floodplain, flood depths and velocities, potential for debris, building contents, and function;
- Complies with all other requirements for new floodplain construction;
- Is “wet-floodproofed” with an appropriate number of flood vents; and
- Does not increase risks to public safety.
View the Administrative Variance Request form. Variance applications should be submitted with an individual FDP application.
Bridge Construction
For more information about permit requirements, please visit the Bridge Construction Permit Requirements page.
Stream Restoration
Visit the Stream Restoration Permit Requirements page for more information.