La Plata County, CO Environmental Rules: Flood Zones (2026)

Chapter 78, Article II of the La Plata County Code is the county's floodplain management regulation. It applies to all special flood hazard areas, and to areas removed from the floodplain by a FEMA letter of map revision based on fill (LOMR-F), within the county's jurisdiction. The minimum mapped area is the FEMA Flood Insurance Study for La Plata County, Colorado, and Incorporated Areas, effective April 25, 2024, with its Flood Insurance Rate Maps and Floodway Maps. The study is on file at the county offices, 211 Rock Point Drive, Durango. The Board of County Commissioners can supplement it with studies designated by resolution after a public hearing, with notice published in a newspaper at least ten days but not more than 30 days before the hearing.

The manager of the county building department is the floodplain administrator. That person approves or denies permit applications, inspects development during construction, records the actual lowest-floor elevation of each new or substantially improved structure, and interprets mapped boundaries. Where a base flood elevation appears on the profiles and tabulations, it governs over the mapped boundary. Anyone contesting a boundary gets a reasonable opportunity to appeal but must back the appeal with technical engineering data.

The permit application comes in addition to regular development review. It includes plans in duplicate drawn to scale, the building site elevation, the difference between the site and stream bed elevations, the lowest-floor elevation, and a description of any watercourse to be altered or relocated. A Colorado registered professional engineer prepares and certifies the submittal, though a registered land surveyor can provide the elevation data. Appendix A lists one floodplain development permit fee per single family residential unit and a separate line for commercial, multifamily or multiple lot subdivision projects.

For subdivisions and other development proposals, no building sites are approved in any determined floodway area, and no floodway encroachment is allowed that would increase flood levels during a base flood. Until a regulatory floodway is designated, no development can raise the base flood water surface elevation more than one-half foot. Proposals with at least 50 lots or five acres, whichever is less, must generate base flood elevation data.