Agenda Date: 05/20/2025
Subject:
Title
Resolution 46-2025: Adopting the Flood Hazard Area Delineation study “Dad Clark Gulch FHAD Floodplain Development Permit”, dated December 2024
Body
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From: |
James L. Becklenberg, City Manager |
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Prepared by: |
Brent Soderlin, Director of Public Works & Utilities |
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Sarah White, Water Resources Manager |
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Presentations: |
N/A |
PURPOSE:
Adopting the Flood Hazard Area Delineation (FHAD) study for “Dad Clark Gulch FHAD, Floodplain Development Permit” prepared by Westwood Professional Services, dated December 2024.
LONG-TERM OUTCOME(S) SERVED:
Safe Community; High Quality Governance
DISCUSSION:
The City of Littleton, in partnership with Mile High Flood District (MHFD), conducted a study to update the Dad Clark Gulch floodplain within the City of Littleton limits west of Santa Fe to the outfall at South Platte River, titled “Santa Fe Park South, Dad Clark Gulch FHAD Floodplain Development Permit”, dated December 2024. With approval recommendation of MHFD, the Colorado Water Conservation Board adopted the revision to the Dad Clark Gulch floodplain by their Resolution 25-752 on March 19, 2025.
Staff recommends adoption of this floodplain delineation for Dad Clark Gulch to meet the intent of Municipal Code 10-7-1.3(B) which states, “Basis for Establishing Floodplains. Floodplains and special flood areas shall be the boundary of the 100-year floodplain (1% chance floodplain). The extent of this area shall be based upon the best available information including:
(2) FHADs. Flood Hazard Area Delineation (FHAD) studies produced by the Mile High Flood District, as may be amended and updated, hereby adopted by reference as part of these regulations when adopted by Mile High Flood District and Colorado Water Conservation Board, and subsequently by the Council.
Adoption of the Santa Fe Park South, Dad Clark Gulch FHAD Floodplain Development Permit report and associated new floodplain boundaries will allow the issuance of Certificates of Occupancy within the Santa Fe Park South development for parcels that were previously in the floodplain prior to its modification, and per the Subdivision Improvement Agreement executed for said development.
BACKGROUND:
The Dad Clark Gulch floodplain was originally delineated in November 1990 through “FHA for Lower Dad Clark Gulch and DFA 0068” completed by Mile High Flood District (formerly known as Urban Drainage and Flood Control District) and the City of Littleton. The existing Dad Clark Gulch floodplain conveys a watershed from Highlands Ranch until its embankment at McLellan Reservoir, a water supply reservoir for the City of Englewood, Colorado. Dad Clark Gulch is channelized west of the Reservoir under Santa Fe Drive, then spreads out until its ultimate outfall into the South Platte River.
Toll Southwest LLC has been approved to develop the property located west of Santa Fe Drive, south of Mineral Avenue and north of C-470. This development, known as Santa Fe Park South, consists of 77.6 acres and will be a combination of single-family residential homes and commercial and mixed-use zoning. The existing Dad Clark Gulch regulatory floodplain encompassed a majority of the proposed Santa Fe Park South development.
The Outfall Systems Plan (OSP) for Lower Dad Clark Gulch was adopted in April 1990. The OSP provided alternatives to modify Dad Clark Gulch for future development in the Santa Fe Park area. The Santa Fe Park South development generally follows that alternative provided in the 1990 OSP, with the exception for routing of Dad Clark Gulch to the north instead of following the existing channel. The Santa Fe Park South development was approved by the City of Littleton with the condition of the Dad Clark Gulch Channel Realignment being mapped and adopted by the CWCB and the City of Littleton. Per the executed Subdivision Improvement Agreement, adopted revisions of the Dad Clark Gulch floodplain are required prior to the issuance of Certificate of Occupancy for any lot within that existing floodplain, and the lowest finished floor elevations of any structures must be verified prior to Certificate of Occupancy for all lots and structures adjacent to the adopted revised Dad Clark Gulch floodplain.
The City of Littleton, in partnership with Mile High Flood District, conducted a study to update the Dad Clark Gulch floodplain with portions within the city limits, titled “Santa Fe Park South, Dad Clark Gulch FHAD Floodplain Development Permit”, dated December 2024, prepared by Westwood Professional Services. MHFD reviewed and recommended the FHAD to CWCB for adoption. The CWCB adopted the revision to the Dad Clark Gulch floodplain by their Resolution 25-752 on March 19, 2025.
In compliance with the City of Littleton Municipal Code 10-7-13 (B)(2) stating “Flood Hazard Area Delineation (FHAD) studies produced by the Mile High Flood District, as may be amended and updated, hereby adopted by reference as part of these regulations when adopted by Mile High Flood District and Colorado Water Conservation Board, and subsequently by the Council”, staff is recommending the revised Dad Clark Gulch floodplain be adopted by City Council.
The portion of Dad Clark Gulch west of McLellan Reservoir is not currently a Federal Emergency Management Agency (FEMA) floodplain due to the smaller drainage basin size (less than 1 square mile) but is regulated by the city as a “local floodplain” as identified in the city’s Storm Drainage Design and Technical Criteria Manual. The FHAD update is not currently proposed to be submitted to FEMA for federal regulation of Dad Clark Gulch and will continue to be locally regulated.
Prior Actions or Discussions
N/A
FISCAL IMPACTS:
N/A
STAFF RECOMMENDATION:
Staff recommends approval of the resolution.
ALTERNATIVES:
With approval of this resolution, the city remains in compliance and good standing with the State of Colorado floodplain regulations. If not approved, the city will not be enforcing the floodplain regulations on the best available information for Dad Clark Gulch. Nor will the city be acknowledging the State regulatory floodplain for Dad Clark Gulch, a violation of the state floodplain regulations.
PROPOSED MOTION:
Proposed Motion
I move to approve Resolution 46-2025 adopting the Flood Hazard Area Delineation study for “Dad Clark Gulch FHAD, Floodplain Development Permit”, dated December 2024.