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 continue to lay stormwater pipe

Crews continue to lay stormwater pipe towards the manhole #19 structure.

Excavation for shoring and its installation begins

The excavation for the shoring and its installation is now underway and will continue into next week.

Drilling and setting of beams for manhole shoring

The drilling and setting of beams for manhole shoring is now underway.

Paving on the west side of Welton is completed

Paving on the west side of Welton has been completed.

Expect to see paving happening around the job site

Base paving has been underway around the job site.

Concrete repairs and restoration work is underway

Concrete repairs and restoration of sidewalks, planters, ramps and curb / gutter are underway throughout the job site.

Phase 3 Construction Update - 5/11/22

Status: Excavation for the shoring—and its installation for the two manhole structures in Washington Street—should finish up this week. The construction of those structures will begin next week and will continue for approximately two weeks. The installation of a lateral across 25th will start next week as well. Crews continue to lay stormwater pipe towards the manhole #19 structure. Watch for some restoration work and cleanup of the site as the structure building work is underway.

Current Impacts: Ongoing planter work, signage, landscaping, and eventually striping will cause some intermittent lane closures along California—and along 26th from California to Welton—so watch for those.

Washington Street remains closed just to the south of the 25th Ave. and Washington intersection—to the alley on Washington between 25th Ave. and 24th Ave.—for manhole / junction structure and inlet construction. Welton to Glenarm is closed, but open to local traffic. The intersection of Glenarm and 26th Street is closed, but local traffic will be allowed through that intersection when construction crews are not present. Local access for residents on 26th Street is still available through the alleys and Welton, with access from Glenarm now that base paving between 26th and 25th is complete. 25th Ave. is now closed from the intersection of 25th Ave. and Washington Street to the alley between Washington and Clarkson. Washington has local access from 25th Ave. to 26th Ave.   

Welton remains open during construction unless we encounter an unforeseen safety issue causing a temporary closure. RTD’s Light Rail remains open at all times during construction. Business access remains open. Please continue to follow all suggested detour routes.

Have a Question?: It’s easy to reach us. Just email, text or call the hotline and we will get back to you as soon as possible. 
Have a great weekend

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 to bid in summer 2022
  • Construction begins early 2023

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