SEMSWA’s Floodplain Program issues Floodplain Development Permits (FPDPs) for projects in and around the 100-year floodplain within our service area. A FPDP must be approved before other local permits (e.g., building, street cut, right-of-way use, GESC, public improvements) can be issued and prior to any other development, use, or change of use of land located in the Floodplain. 

All activities, regardless of impact, need to be permitted. Even when it is apparent that there are no adverse impacts to the floodplain, a permit is required for administrative purposes to ensure that SEMSWA is aware of the activities within the floodplain and that they have been evaluated for compliance with Arapahoe County requirements.  

Arapahoe County Floodplain Regulations and Permitting Requirements follow Federal and State criteria and are authorized through the County Land Development Code and are described in detail in the SEMSWA Stormwater Management Manual and the Arapahoe County Stormwater Management Manual.

Hydraulic modeling may be required to determine if the proposed project will cause an impact to the floodplain.

• No impact means 0.00 ft rise in the Base Flood Elevation (BFE) and no additional width added to the floodplain. 
• Impact is defined as any rise in the BFE and/or additional land added to the width of the floodplain. 

1. Floodplain Development Permit (FPDP)
   1. No Impact FPDP for no impact projects - An Engineer’s Certification of No Impact is required for administrative purposes for FPDP with no floodplain impact. In some cases, hydraulic modeling could be required.
   2. Standard FPDP for projects with impacts to a floodplain
      1. If the impacts will occur to a FEMA floodplain, a Conditional Letter of Map Revision (CLOMR) must be submitted and approved by FEMA prior to approval of the FPDP.
      2. If the impacts will occur to a local floodplain, i.e., a FHAD floodplain or an area of approximately mapped flood hazard, a Floodplain Modification Study (FMS) must be submitted to and approved by SEMSWA prior to approval of the FPDP. The FMS is a project-specific study on floodplain impacts.

If you are concerned about buildings, sheds, or fences you see being built near waterways and known floodplains, please reach out to SEMSWA. 

1. Call SEMSWA at 303-858-8844
2. Contact us using the Contact Us form

<City specific table coming soon...>

Arapahoe County Floodplain Development Permit Application

Use for all proposed projects located in the floodplain within Unincorporated Arapahoe County:

Arapahoe County Floodplain Development Permit (link to Arapahoe County website)

No Impact Letter Template

CLOMR/LOMR Templates

FEMA MT-1 and MT-2 Forms

1. MT-1: The FEMA forms for individual property owners (LOMA, LOMR-F) are located at:   https://www.fema.gov/flood-maps/change-your-flood-zone/paper-application-forms/mt-1
2. MT-2: The FEMA forms for larger projects (CLOMR/LOMR) are located at:  https://www.fema.gov/flood-maps/change-your-flood-zone/paper-application-forms/mt-2

In an effort to make the floodplain permitting process more efficient and accommodating to consultants for certain routine projects that cause no impacts to the floodplain within Unincorporated Arapahoe County, the SEMSWA Floodplain Department has created two Annual Floodplain Development Permits.  These Annual Floodplain Development Permits are being offered to Utility Companies as well as to the Parks and Recreation Districts for projects located within Unincorporated Arapahoe County. 

Annual Floodplain Permit Application