Sanderson Gulch Channel Improvements

Project Overview

Sanderson Gulch, near the confluence with South Platte River in the Ruby Hill Neighborhood, is a highly urbanized channel in a narrow corridor adjacent to commercial properties. The existing channel, railroad bridge and culverts had inadequate capacity for major storm conveyance. Nearly 100 commercial and residential properties are at risk of flooding and are located in the regulatory flood hazard area. The goals of the FEMA grant funded project were to increase channel and culvert capacities; remove properties from the floodplain; and incorporate natural channel design elements to the system to improve ecology and stream health.

The final design included a complex system consisting of low flow culvert and channel that sit overtop of the high flow culverts. There is also a water quality vault for base flows and distinctive stacked slabstone boulder drop structures for grade control. Other project elements include roadway realignments, major utility relocations, trail expansion and a specialized revegetation and planting plan. Project challenges included railroad closure coordination and contaminated soil and groundwater handling.

Project Outcomes

• Increased stormwater capacity for Sanderson Gulch through innovative design
• Reduced flood hazard potential
• Installed water quality vault structure
• Utilized a site-specific plant palette to secure desired native plants
• Mitigated contaminated soils
• Established long-term stream health and stability
• Provided trail connections and increased pedestrian safety