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Utilities

Oak Street Stormwater Improvements Project#

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The Oak Street Stormwater Improvements Project is one of several stormwater projects that have been identified as part of the overall Downtown Stormwater Improvement Program (DSIP) and will contribute to resolving the urban flooding issues in downtown Fort Collins.

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map of DSIP projects

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This project has been identified as the top priority project in the DSIP for these six reasons:#

1. It will significantly contribute to resolving the urban flooding issues in downtown Fort Collins.

Flooding at Mulberry and College.

Flooding at Mulberry and College.

Flooding at Mulberry and College.

Flooding at Mulberry and College.

Flooding at Lincoln Center.

Flooding at Lincoln Center.

Flooding near Mulberry and Mason.

Flooding near Mulberry and Mason.

2. Constructability ranks higher for this project because the outfall is already constructed and there are less major street crossings than other DSIP projects.

3. It is an extension of the previously constructed Oak Street Outfall project, able to utilize the existing outfall to the river and existing pipe/inlet infrastructure from the river to Mason Street.

oak street stormwater construction

Stormwater pipe installation in Oak Street.

4. Public impact due to construction duration is comparatively less than the other DSIP projects.

5. Permitting requirements are minimal compared to other projects identified in the DSIP.

6. Construction cost is estimated to be less than other DSIP projects at $23.5 M.

What to expect during construction:#

Constructing stormwater inlets in Mason Street.

Constructing stormwater inlets in Mason Street.

Storm pipe construction in a Fort Collins urban neighborhood street.

Storm pipe construction in a Fort Collins urban neighborhood street.

Storm structure installation in a Fort Collins urban neighborhood street.

Storm structure installation in a Fort Collins urban neighborhood street.

This project will be an extension from the Oak Street Outfall constructed in 2001. It will extend west on Oak Street from Mason to Jackson Street. Approximately 8,500 linear feet of new stormwater mains will be installed, ranging in size from 48-78 inches in diameter. This includes several “lateral” extensions from the main spine on Oak Street, north to Mountain Avenue or south to Olive Street, that will connect to existing storm lines and improve inadequate drainage at these locations.

Significant features of this project are:#

  • This is a large diameter storm sewer system with large junction structures and pipe, to be installed at significant depth in some areas.

  • The alignment will cross the Arthur Ditch (at Whitcomb Street) and Shields Street (a major arterial street). Both crossings will require alternatives analysis to determine sound constructability while meeting the requirements of the Ditch Company and City Traffic department for road closures.

  • The project will incorporate green infrastructure (or Low Impact Development systems) within the right of way (ROW) that will be added into updated or enhanced streetscaping. Continuing design efforts will incorporate concepts from guiding documents such as the 2017 Fort Collins Downtown Plan, which includes updated streetscape guidelines that may be integrated with stormwater quality systems within the ROW.

  • The project is in downtown Fort Collins where the existing ROW can be constrained with other utilities, trees and parking, and where continuous coordination and accommodation with other users of the ROW, including business owners, residents, pedestrians and traffic, will be required.

  • The size and scope of this project is likely to impact other utilities, including water distribution and sanitary sewer collection mains. Several mains in the area have been identified in the City of Fort Collins Water and Wastewater Masterplan (2018) as needing replacement due to poor condition or age. The mains may be relocated to accommodate the new storm sewer system. Specific water and sanitary sewer work will be identified during design.

Timeline#

DSIP Analysis & Outreach
DSIP City Council Worksession
Oak Street Project Identified as the first project
Design
Construction

Project Consultants and Contractors#

  • Anderson Consulting Engineers
  • BHA Design
  • BT Construction
  • Connell Resources

Oak Street Outfall Project#

The Oak Street Outfall project, constructed downtown in 2001-2002, consisted of large diameter pipe and storm inlets, two tunnels and 25 acres of water quality ponds.

Constructing stormwater inlets in Mason Street.

Constructing stormwater inlets in Mason Street.

Stormwater tunnel under Oak Street and College Avenue.

Stormwater tunnel under Oak Street and College Avenue.

96" pipe diameter tunneled under railroad tracks near outfall to the Poudre River.

96" pipe diameter tunneled under railroad tracks near outfall to the Poudre River.

High-flow weir at the outfall to the Poudre River.

High-flow weir at the outfall to the Poudre River.

Storm pipe installation near Remington.

Storm pipe installation near Remington.

Storm pipe shoring and installation.

Storm pipe shoring and installation.