Areas of Work & Schedule
Resilient St. Vrain: Restore & Revitalize
The Resilient St. Vrain project is divided into work areas called reaches. A reach is an engineering term used to describe a particular section of river or creek.
Construction on this very large project is taking place in phases. It began at the downstream end of the St. Vrain Creek (at Sandstone Ranch) in 2016. The work will take many years to fully complete, including time for vegetation to take hold and grow. All construction dates and costs are estimated and subject to change as the project progresses. View funding and estimated construction dates for reaches >
Current Reaches
The City Reach follows the St. Vrain Creek through urban, developed areas of Longmont. Construction work here is:
- restoring the flood-damaged St. Vrain Greenway
- protecting people, property and infrastructure by improving the creek channel
- reducing future flood risks by shrinking the size of the floodplain
- being completed in an environmentally responsible manner
Boston Avenue Bridge
UNDER CONSTRUCTION
- Contract was awarded in May 2023
- Construction began in the summer of 2023 and is expected to last 24 months and be completed in the summer of 2025
Future Reaches
Hover Road Reach (Sunset Street to Hover Road)
- This work includes a split-flow channel through Fairgrounds Park and a new box culvert/bridge under Hover Road
- City of Longmont voters approved $20 million in Storm Drainage Bonds in 2022
- The City is awaiting grant application prior to the issuance of the bonds
- Designs have been completed. This work will commence when bonds are issued. It is expected to take approximately 18-24 months.
Channel improvements on Izaak Walton Reach 2: Boston Avenue to Sunset Street
FINAL DESIGN
Longmont has entered into a Public Partnership Agreement with the U.S. Army Corps of Engineers for final design and construction of Izaak Walton Reach 2. This phase includes channel improvements between Boston Avenue and Sunset Street. Learn more about the USACE process >
- Channel improvements between Boston Avenue and Sunset Street including a levee between Izaak Walton Pond and the creek. Final design and construction of this phase of the project will be managed by the U.S. Army Corps of Engineers.
- Final Design is complete.
- Land acquisition and floodplain permitting is pending
- Construction is expected to start in fall 2023 and is expected to last approximately 18 months to be finished in summer 2025.
- Sunset Street Bridge has been replaced.
- Once work has been completed in this reach, the floodplain to the north of the St. Vrain Creek will be mitigated protecting lower downtown from future flood risk.
Hover Road upstream to Airport Road
CURRENTLY UNFUNDED
- Completing work through Roger’s Grove/Hover Road would achieve the Resilient St. Vrain project’s goal of removing the majority of the developed portions of Longmont downstream (west) of Hover from the 100-year floodplain.
- Final design work on these areas has not yet begun, and funding has not yet been secured.
- Creek crossings at Hover Street and Airport Road are in this reach.
Completed Reaches
Izaak Walton Reach 1: Upstream of BNSF Railroad Bridge (Price Road) to Boston Avenue
COMPLETED in 2022
- A sanitary sewer pipe that crosses the St. Vrain Creek upstream of the Boston Avenue Bridge was relocated.
- Modular block walls were installed in this reach.
- This is the shortest reach within the Resilient St. Vrain project.
LOMR #1
RECEIVED FEDERAL APPROVAL
The new floodplain maps (Preliminary FIRMs) have been updated with the projects listed below that have been completed along the St. Vrain Creek.
The first Letter of Map Revision (LOMR #1) to the Preliminary FIRMs include the updates for the completion of:
- Sandstone Ranch Reach
- County Line Road Bridge
- City Reach 1, including Dickens Farm Nature Area and Boston Avenue
- Main Street Bridge
- South Pratt Parkway Bridge
- City Reach 2A, Main Street to Colorado Way (just west of S. Pratt Parkway)
As shown in the figure below, LOMR #1 begins to remove property downstream of BNSF railroad and south of the creek from the 100-year floodplain. Click on the map image to open a PDF version that can be viewed larger or downloaded.
Map key:
- Blue (Preliminary FIRM and 2012 Effective) represents the 100-year floodplain.
- Black crosshatch area represents the property removed from the 100-year floodplain with LOMR #1.
The LOMR #1 final report is available for viewing and download at this link. The complete RSVP LOMR #1 report, including appendixes, large computer model and GIS files, is available by request from Longmont’s Floodplain Administrator.
City Reach 2B: West of South Pratt Parkway to BNSF Railroad Bridge (Price Road)
COMPLETED 2021
- BNSF Railroad Bridge has been replaced as part of an agreement between Longmont and BNSF.
- The St. Vrain Creek channel was improved to help protect the community from future flood risks.
- Modular block walls were added in this reach.
- The contractor completing fencing, irrigation and landscape planting in this area.
City Reach 2A: Main Street to just west of South Pratt Parkway
COMPLETED FALL 2019
- This reach includes a wider creek channel between Main Street and South Pratt Parkway.
- Modular block walls are being installed in the tighter urban corridor west of South Pratt Parkway.
- Over 150,000 native plants will be added, along with over 30,000 square feet of wetland sod and nearly 10 acres of seeding. View a list of species planted through the Resilient St. Vrain Project >
- South Pratt Parkway Bridge has been replaced.
- The St. Vrain Greenway is fully open from South Pratt Parkway east to Sandstone Ranch.
City Reach 1: Left Hand Creek confluence (east of Martin Street) to Main Street
COMPLETED SUMMER 2018
- Main Street Bridge has been replaced.
- Dickens Farm Nature Area has been completed and is now open.
Sandstone Reach
COMPLETED SPRING 2018
Sandstone Reach follows the St. Vrain Creek through the Sandstone Ranch Nature Area and surrounding open space. Construction began in November 2016 and continued through spring 2018.
Goals of work in this area were to:
- restore the flood-damaged St. Vrain Greenway. The trail is now fully open though this area
- stabilize creek banks to protect trails, access roads and infrastructure from future flood damage
- help nature re-establish vegetation and wetlands habitat for fish and wildlife. Nearly 200,000 native plants were added. View a list of species planted through the Resilient St. Vrain Project >
