US 36 Lyons to Estes Park


Damage Overview

In September 2013, flooding ravaged many parts of Colorado and caused wide-spread destruction to communities, rivers, and transportation systems.  The Colorado Department of Transportation (CDOT) was faced with an overwhelming challenge of repairing, rebuilding, and reopening hundreds of miles of flood-damaged roads and bridges in order to restore connections and help speed the recovery process.

During the flooding, Estes Park, a town of approximately 5,900, was essentially stranded because the three highways providing connectivity into and out of the Town were impassable due to flood damage.  One of the most heavily destroyed roadway systems was US 36 from Estes Park to Lyons.  A CDOT damage assessment team was sent out immediately after the rains stopped and an inventory identified 17 damaged sites from MP 7.7 to 18.6.  At each of the 17 sites, the river undermined the roadway embankment, in some places down to bedrock.  The washouts caused the road sections, including asphalt, road base, guardrail, and signing, to collapse into the river.  The failed road was carried downstream, leaving massive debris fields that included uprooted trees, cars, river rock, sand, and a collection of private property from flooded houses in the river beds.

Because the Department had never experienced such large-scale destruction, out-of-the-box thinking was encouraged, as well as innovative collaborations.  Soon after the damage was assessed on US 36, CDOT contacted Central Federal Lands (CFL), a division of the Federal Highways Administration (FHWA), to pursue a partnering opportunity.  CFL is an agency responsible for designing and constructing road systems in National Parks, National Forests, defense areas, Indian reservations, and other Federal property areas.  CFL agreed to be a part of the US 36 reconstruction efforts and an agreement was executed in October 2013 to join forces.  The CDOT/CFL partnership is the first known alliance in Colorado that involved state and federal transportation agencies collaborating on an emergency/permanent repair project.  The Partnership Agreement involved CFL designing the project and taking the lead during construction on Phase I (Emergency Repairs), with CDOT taking the lead on construction in Phase II and Phase III (Permanent Repairs).

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The Project team was formulated and the Project criterion was given: construct a safer and more resilient roadway that will ensure connection between Estes Park and the Front Range when another large flood event occurs.  In order to accomplish the mission, the road had to be moved away from the river and into the mountain between 5 and 50 feet, depending on the location.  Accident history was also analyzed and problematic areas were identified and approved for safety improvements and curve softening.  A road template adding 6-foot-wide shoulders in each direction and a 10-foot-wide rock ditch was incorporated into 3 miles worth of reconstruction areas within the project to increase safety through the canyon.  

Emergency (Temporary) Repairs

Phase I was structured to address the emergency repairs and was completed in July 2014.  Work involved repairing approximately three miles of roadway from MP 10.9 to 11.3 and 16.2 to 17.8.  The majority of the work involved excavating and blasting (in total 122 shots were performed) approximately 250,000 cubic yards of rock.  A large portion of this rock was donated to local agencies, towns, and counties to help with their own flood repair efforts.  Phase I also included building up the subgrade, laying base, paving the bottom mat of asphalt, armoring the road embankment with large rip rap (boulders roughly 5 feet in diameter) and restoring functionality to the stream to avoid future damage to the roadway during spring runoff.

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Permanent (Long-Term) Repairs

Phase II work addressed the permanent repairs and commenced in July 2014 and is expected to be completed in Summer of 2015.  Work included paving the final two mats of asphalt and installing guardrail, signing, and striping.  Also included in Phase II was rebuilding an approximate mile-long stretch of road from 17.8 to 18.7, as well as completing the stream restorations.  Once completed, the improved stretches of roadway now have 12-foot lanes with 6-foot shoulders. Pre-flood, there were 12-foot lanes with minimal shoulders. Not only will the additional shoulders help widen the highway, but the shoulders will also help improve safety by providing space for emergency pull-offs and making it safer for bicyclists. Furthermore, by softening some of the mountain curves, sight distance will be improved along several of the more severe curves on US 36, including Dead Man’s Curve and the approach to Longmont Dam Road.

Estimated Timeline

  • Project Complete

Estimated Budget

  • $10 to $20 million (combined Phase I and Phase II)

Phase III work will continue to address the permanent repairs and commence in April 2019 and is expected to be completed in Spring of 2020.  Work includes removal and replacement of fill, riprap, and pavement between Milepost 7.7 and 8.  

Estimated Timeline

  • Est. Design Start: Summer 2015
  • Est Construction Start: Spring 2019

Estimated Budget

  • $4 - $10 million


The 2013 flood event presented a unique opportunity for the US 36 Project to take a holistic corridor approach and partner with stream restoration experts while rebuilding the highway.  CDOT and CFL sought out the Colorado Water Conservation Board (CWCB) and Crane and Associates to help guide the stream restoration efforts.   The Team leveraged materials, equipment, manpower, and expertise onsite to responsibly rebuild the corridor by identifying how the river and road interact with each other.  This evaluation helped identify opportunities and best practices that mutually benefited multiple elements.

The priority of the US 36 stream restorations was to utilize onsite resources to stabilize the stream in the near term and stimulate aquatic, riparian, and plant habitat.   Stream stabilization and wildlife promotion efforts included creating low and high flow channels, installing energy dissipaters and tree root balls, building fishing holes and passive recreational accesses, and contouring river banks.  The St. Vrain Creek Coalition is currently working on a Master Plan that will further identify and address river and recreational needs and prioritize projects.

In future flood events, the river will have more area to expand in some areas and the road will be better armored to withstand the water’s force, which will reduce undermining and washout, and help keep communities connected.

Media Contacts

Jared Fiel
CDOT Communications Office
[email protected]

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