27th Street Storm Interceptor Project

Web banner for 27th Street Storm Interceptor project

27th Street Storm Interceptor Project will improve public infrastructure and safety, relieving drainage and flooding issues in Five Points, the Curtis Park neighborhood and the RiNo Art District.

Banner for Phase 3 of the 27th Street Storm Interceptor project 

PHASE 3: In addition to providing flood relief in the immediate area, the new, enlarged 27th Street stormwater system will work in concert with stormwater systems along 33rd and 36th Streets to provide greater flood protection to the larger area.

This project will employ both open trench construction and tunneling methods. Tunneling will occur for the portion beneath Welton and the RTD Light Rail tracks, allowing Welton to stay open for the duration of the work.

In addition to installing a new large diameter pipe, this project will also include:

  • new ADA ramps
  • sidewalk
  • curb / gutter
  • tree planters
  • large inlets constructed on Washington between 25th and Welton to alleviate flooding in the immediate area 

Project Map

Map of 27th Street Storm Interceptor Project area

Current Impacts

Current Impacts map for 27th Street Storm Interceptor project

Crews backfilled around this manhole this week.

Crews backfilling dirt around a manhole before pouring concrete.

A completed manhole tied into the brick pipe.

Photo showing a recently completed manhole tied into the existing brick pipe.

Completed paving on 26th from Welton to Glenarm

Photo of completed paving on 26th Avenue—from Welton to Glenarm.

Clean-up, landscaping and restoration work

Lots of clean-up / landscaping / restoration work is currently occurring along the construction route.

Steel casing connecting old pipe into new system

Photo of the new steel casing that connects the old brick storm pipe into the new system.

Old pipe being prepared for tie-in with new pipe

Photo of the old brick 27th Street stormwater pipe being prepared for the tie-in with the new pipe.

Phase 3 Construction Update - 7/29/22

Status: The building of inlets is in full steam ahead mode. Concrete work—curb / gutter, ramps and sidewalks along 25th, Glenarm, and Washington—will begin after we have the inlets finished, hopefully by the end of next week. And when the concrete work wraps up, final paving will begin. It continues to look like the end of August for paving, if we have no unforeseen events.

Weather: ’Tis the season for monsoon rains, and we have certainly been navigating around the weather the past few days—having to take time to dig mud out of the project area. Please remember that all schedules are weather dependent.

Current Impacts: Washington Street is closed from Glenarm to the alley on Washington between 25th Ave. and 24th Ave. 25th Ave. is closed between Clarkson and Washington Street, and local traffic has one lane of access until the inlets and ramps are completed. 26th Street is now open between Welton and Glenarm through the intersection of Glenarm and 26th Street. Glenarm is also now open from 26th to Washington. 

Welton continues to remain open during construction unless an unforeseen safety issue causes a temporary closure. RTD’s Light Rail remains open at all times during construction. Business access always remains open. Please continue to follow all suggested detour routes.
Does Your Business Need a Financial Boost?: The City’s Business Impact Opportunity Fund is a program that provides strong and efficient support to small businesses. A new round of construction impact grant applications opened July 11th for businesses impacted by the construction, and a third round will open in early September. Please visit this site for lots of information on the program.
Please Reach Out: It’s easy to contact us via email, or call / text the hotline if you have a question or concern.
Since we are focusing on inlet construction now, we are going to skip next week’s update—but we will be back in touch the week of August 8th with the latest news.

Thanks, everyone

Phase 4 header for 27th Street Storm Interceptor Project

Upcoming Phase 4 Information

This project will improve public safety by installing a large storm drain to relieve drainage and flooding issues in Five Points, the Curtis Park neighborhood and the RiNo Art District.  This storm drain project will pick up where the current Phase 3 leaves off.

  • Anticipated Construction: 2025

Additional improvements will include:

  • ADA ramps
  • Sidewalk improvements
  • Curb/gutter
  • New inlets and laterals at all intersections
  • Bikeway improvements in conjunction with the 22nd Ave. Bikeway Project
  • Full asphalt replacement


  • Closures limited to two blocks and two intersections at a time
  • Pedestrian access to residents and businesses inside the project area will always be open
  • Signage will clearly define and direct detour routes 

Phase 4 Project Map

Phase 4 map for 27th Street Storm Interceptor Project

Phase 2 Archive

Status: Construction was completed in Fall 2020

Sod Watering: The contractor initially watered the new sod, and now it becomes the responsibility of the property owner.

During this project we have appreciated your patience with closures, water service interruptions and all of the inconveniences projects of this type bring. Thank you for working with us along the way.

Project Map

Phase 2 map for 27th Street Storm Interceptor project

Construction Impacts

27th Street will be closed to traffic in sections up to two blocks at a time, between Arapahoe and California Streets. Traffic will be detoured onto adjacent streets as needed, but residential, business and pedestrian access will be maintained via secondary access points or through the construction zone.

Existing water lines and sanitary sewer lines will need to be relocated to accommodate the new storm sewer pipe.  Businesses and residences along 27th Street (between Arapahoe and California Streets) will have temporary water and sewer disruptions to complete the relocation work. Advance notice will be provided to those who will be impacted.

Construction Methods

Storm drainage systems are far beneath the surface of city streets, and thus require shoring of the excavation sites to ensure the safety of the workers below. There are many types and methods of shoring that have been used on previous stormwater projects — some of these methods are more invasive than others. Sheet piling and beam and lagging shoring systems are examples of shoring methods that are more invasive. Slide rail and trench boxes are examples of the less invasive shoring systems. 

This phase of the 27th St. Storm Interceptor project is far less complicated than Phase 1, thus it is likely that the contractor will be using minimally invasive shoring methods combining the use of slide rail systems and trench boxes. We do not anticipate that the contractor will need to use sheet piling or beam and lagging to complete this project, and therefore we do not anticipate any vibration issues on Phase 2.

There will be a monitoring system in place, similar to what was in place on Phase 1. Anyone with questions or concerns about vibration issues can contact the CCD project manager, Aaron McMichael, to resolve the issue.


The 27th Street Storm Interceptor project is one of several large-diameter storm drain projects to relieve drainage and flooding issues in the Five Points and Curtis Park neighborhoods and the RiNo Art District. Currently in this area, stormwater runoff drains to the South Platte River at the over-burdened 36th Street Outfall, leading to flooding during storms. When complete, the new storm drain system will connect to an existing 108-inch storm drain at Coors Field Parking Garage at Blake Street, balancing water flow between multiple systems and resulting in less flooding along the 27th and Washington Street corridors.

Phase 3 and additional future phases of the project are still in design, but the alignment is expected to run from the end of Phase 2 down California Street to 26th Ave, southeast along 26th Ave to Washington Street and continue south down Washington Street toward 20th Ave. These future phases are still seeking funding approval. 

The 27th Street Storm Drain project was first identified in the 2005 Stormwater Master Plan. This project is a high priority focus stormwater basin and was included in the 2016-2021 Six-Year Capital Improvement program.

Phase 1 Archive

Phase 1 construction began at the Coors Field Parking Garage in October 2018 and continued upstream (eastward) along 27th Street to Arapahoe. This phase was completed in June 2019.

Meeting Materials