Fourmile Canyon Reconstruction

Fourmile Canyon Drive Reconstruction & Fourmile Creek Restoration

Boulder County Transportation and the project contractor, Lawrence Construction, hosted a public meeting on Aug. 29 to share information about the project regarding working hours, phasing, travel impacts, staging, etc. and answer questions. Staff from the county and Lawrence were on-hand. View the meeting handout.

Construction will start in early October 2018, but surveying and other preparatory activities are underway.

  • Construction Logistics
    • 8 a.m. to 4:30 p.m. – Monday through Friday – No work on major holidays
    • Delays (for this project) can total 15-minutes between CO Hwy 119/Boulder Canyon & Salina Junction
      • There can be delays on other sections of the road for separate projects (Logan Mill & Upper Fourmile – Salina to Sunset)
    • Work may require longer delays or road closures due to work taking place underneath the road
      • We are hopeful there will only be single-lane closures, but certain activities may not be feasible and/or safe without a road closure
    • Work will take place in two separate zones
      • South Zone – 1-mile up from CO 119 to Poorman
        • Work will begin in this zone in October 2018
      • North Zone – Logan Mill Road to Salina Junction
        • Work will begin in this zone in early 2019
    • No Blasting
      • Retaining walls will be built on the stream side
      • Drainage improvements
      • Streambank/roadside armoring & stabilization using walls and rip-rap
    • 8 a.m. to 4:30 p.m. – Monday through Friday – Until further notice
    • Residential cycling excepted
      • Must carry valid identification proving residency
      • Residents can also receive a cycling pass that they can show – contact information at the bottom of this page
    • Cycling allowed on major holidays when no work is taking place – Labor Day, Thanksgiving, Christmas, New Years Day, etc.
    • Map of restricted roads
    • Boulder County Sheriff’s Office enforcing restrictions
      • Violators could be subject to citation by law enforcement
    • Restrictions in place due to safety concerns stemming from extremely high volume of flood recovery-related construction activity throughout the canyon.


This webpage is your source for information regarding permanent flood recovery-related reconstruction in lower Fourmile Canyon between Boulder Canyon Drive/CO 119 and Salina Junction.


In September 2013, flood waters either damaged or destroyed approximately 1.5 miles of two sections of Fourmile Canyon Drive between Boulder Canyon Drive and Salina Junction. The lower portion (south section) starts about 1-mile up from Boulder Canyon Drive and extends to Poorman Road, and the upper portion (north section) starts near Logan Mill Road and extends up to Salina Junction. The projects to repair Logan Mill Road/Bridge, Upper Fourmile Canyon & Gold Run Road are separate from this project.

Permanent design plans are currently being refined. The county’s most recent estimate is that construction will start in the Winter/Spring of 2018.


99% Complete Plan Set – Uploaded Aug. 31, 2018

This set is not the construction-ready set that includes information from individual property agreements. Those will be available soon.

90% Complete Plan Set for Roadway Work – Uploaded March 9, 2017

This plan set has been broken into smaller pieces to make the files easier to open. The files below include both the north and south sections of lower Fourmile Canyon Drive (Hwy 119 to Salina Junction). These plans will continue to be revised as we work with impacted property owners.

  • Pages 1 to 34 – Title Sheet, Symbols, Notes, Typicals, Quantities, Tabulations, Survey Control, Key Map, and Geometric Layout
  • Pages 35 to 50 – Removals & Resets
  • Pages 51 to 79 – Tree Inventory*
    • *NOTE – The tree inventory is still being updated and do not depict the actual tree figures. We’re also working on contract language that will require the contractor to save as many trees as possible. While it is unlikely we will be able to prevent all tree removals, we will ensure that only those tree that are absolutely necessary will be removed.There will also be a large revegetation effort at the end of the project.
  • Pages 80 to 109 – Roadway Plans & Profiles
  • Pages 110 to 125 – Driveways
  • Pages 126 to 159 – Creek and drainage plans
  • Pages 160 to 221 – Culverts & Retaining Walls
  • Pages 222 to 250 – Guardrail, Construction Phasing*, and Storm Water Master Plans
    • *NOTE – The Construction Phasing Plans are only suggestions made by our engineering consultant. The county is working internally on a plan to complete this project with minimal impacts to residents and the traveling public.
  • Pages 251 to 291 – Cross Sections

This plan set has been broken into smaller pieces to make the files easier to open. The files below include both the north and south sections of lower Fourmile Canyon Drive (Hwy 119 to Salina Jct.)

Lower Fourmile Creek Stream Restoration Plans – Uploaded Feb. 23, 2017

These are the designs that will be used to guide the stream restoration component of the project. The plan set has been broken into smaller sections for easier downloads.

60% Complete Phase for Roadway

This plan set has been broken into smaller pieces to make the files easier to open. The files below include both the north and south sections of lower Fourmile Canyon Drive (Hwy 119 to Salina Junction). These plans will continue to be revised as we work with impacted property owners.

Lower Fourmile Canyon Drive Reconstruction Options that helped inform the 60% phase.


TREE UPDATE – Feb. 10, 2017

On Jan. 26, members of the Fourmile Canyon Drive engineering team, including Transportation Director George Gerstle and County Engineer Mike Thomas, walked both stretches of lower Fourmile Canyon Drive where the road will be permanently reconstructed to better understand and mitigate impacts to trees, bushes, and other vegetation identified for potential removal.

Each tree identified in the recent draft design was carefully inspected, and possible measures to avoid removal were discussed. The design team has now been charged with saving as many trees as possible through creative design changes, transplanting of trees, or by incorporating special construction techniques to avoid impacts. In addition, we are incorporating language in the construction contracts to incentivize contractors to mitigate impacts to trees during construction. The same tree evaluation will be held with the design team in Gold Run and in upper Fourmile/Wall Street in the coming weeks and the goal will be the same; to save as many trees as possible.

While we will make every effort to mitigate impacts to trees during construction it will not be possible to avoid all tree removals. Based on early public input, the conceptual design of the road repairs were changed to avoid impacts to the canyon walls on the uphill side of the road. The recognized trade-off to these changes was that some increased impacts to creek-side vegetation were unavoidable as retaining walls would be necessary to strengthen and protect the road from future flood events. Where trees must be removed from private property, we are discussing options with the property owner. When a significant tree must be removed from the right-of-way, we will plant a new tree in the canyon, understanding that a new tree is unlikely to be the same as an old-growth tree.

It is our promise to residents that we will make every effort to remove only those trees that absolutely must go to complete the project. We have heard concerns from both residents and visitors to the canyon about the loss of trees from the Fourmile Fire and subsequent flood events, and how that has changed the canyon’s aesthetics. We will do everything we can to minimize more changes to the character of this beautiful canyon as a result of permanent flood repairs.

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Boulder, CO 80304

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