Floodplain No Impact Letter HDR.pdf
PDF 251 KB Posted
- Solicitation number
- 25-09-04
- Issued by
- Arapahoe County, Colorado
About this file
This document is a Certification of No Impact to the Floodplain letter from HDR Inc. to the Southeast Metro Stormwater Authority (SEMSWA), addressing the "Batch 3 – Span Wire to Mast Arm Traffic Signal Rebuilds" project. The project aims to upgrade span wire traffic signals to mast arm traffic signals at three intersections in Arapahoe County, Colorado: East Arapahoe Rd & South Franklin St, East Dry Creek Rd & South Franklin St, and East Dry Creek Rd & South Clarkson St. The improvements include modernizing the traffic signal design and providing curb ramp improvements where necessary.
The letter, signed by Colin McKernan, P.E., CFM, confirms that the project will not impact the floodplain based on the FEMA Flood Insurance Rate Map. The project area is located within Zone AE of the Special Flood Hazard Area, with the intersection of E Dry Creek Road and S. Clarkson Street falling within the regulatory floodway for Littles Creek. The proposed curb ramps will result in a net cut in the floodplain, and the associated sidewalk replacements will be slightly lower than existing, ensuring no increase to the floodplain width or base flood elevation.
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Text version
hdrinc.com
1670 BroadwaySuite 3400Denver, CO 80202-4824
(303) 764-1520
July 14, 2025
Cynthia Love, P.E., CFM Floodplain Manager Southeast Metro Stormwater Authority 7437 South Fairplay Street Centennial, CO 80012-4486
RE: Batch 3 – Span Wire to Mast Arm Traffic Signal Rebuilds
Dear Ms. Love, This letter serves as Certification of No Impact to the Floodplain for the project entitled “Batch 3 – Span Wire to Mast Arm Traffic Signal Rebuilds” The purpose of this project is to upgrade the span wire traffic signals to mast arm traffic signals to provide a more modern, aesthetically pleasing design at the intersections of East Arapahoe Rd & South Franklin St, East Dry Creek Rd & South Franklin St, and East Dry Creek Rd & South Clarkson St.
Curb ramp improvements will be provided where necessary.
The Federal Emergency Management Agency (FEMA) Flood Insurance Rate Map (FIRM) shows the project area located on Panel No. 08005C0453L for Arapahoe County dated September 4, 2010. The project area is located along Littles Creek and is within a designated Zone AE of Special Flood Hazard Area (SFHA), with a regulatory floodway.
The intersection of E Dry Creek Road and S. Clarkson Street falls within the regulatory floodway for Littles Creek.
No increase to either the floodplain width or base flood elevation will result from the project because the impact of the proposed curb ramps relative to the overall floodway/floodplain does not create an impediment of flood flows. The proposed curb ramps will result in a net cut in the floodplain while the associated sidewalk replacements will be slightly lower than existing.
Sincerely, Colin McKernan P.E. CFM Colorado P.E. 39067
07/14/2025
39067
SEMSWA CASE NO. DPR25-00031
File details come from the government source that posted it. Updated .