Boulder County

Fourmile Canyon Flood Recovery

Boulder County, CO

Unprecedented rainfall in north central Colorado caused a 100-year flood event in September 2013 resulting in massive infrastructure damage still being addressed five years later. Boulder County was hit particularly hard with 12-16 inches of rain—nine times the average September monthly rainfall in just four days. Hundreds of miles of roads were washed out, and in some cases, small mountain towns were surrounded by water, making it impossible for residents to leave their homes. Several significantly damaged roadways are still in need of repair or reconstruction.

To initiate reconstruction efforts, Benesch was selected to provide construction management and inspection (CM&I) services for flood damage repairs to the Fourmile Canyon area, including four separate projects within one constrained corridor. A complex scheduling strategy is required to coordinate multiple projects simultaneously. CM&I services include overseeing the construction of several different types of retaining walls, bridge and roadway reconstruction and stream restoration work. Due to the size, locations and unknown sequencing of the four different projects, Benesch and its subconsultants are providing an abundance of inspectors with varying levels of experience and materials testing capabilities to meet project demands. Careful tracking and attention to guidelines for various funding sources is a key component for project success.

Benesch is an experienced flood recovery firm, completing numerous recovery and repair projects in the Front Range of Colorado. Because these projects are unique in their proximity to waterways and developed surroundings, we work closely with contractors to minimize the construction footprint and perform quality, long lasting repairs. As is typical for mountainous construction, these projects have a major impact on the public. Lack of space to easily divert traffic around a work area and the inability to utilize a detour to maintain access means traffic must be maintained through congested construction sites. Benesch is utilizing an extensive public involvement process to balance necessary infrastructure construction with minimal inconveniences to local businesses and residents. In addition, the Benesch team is incorporating sound ecological practices during stream restoration and revegetation to establish a more sustainable and resilient watershed.

Along with oversight of the construction process, Benesch will coordinate with both the Colorado DOT and FEMA to meet standards requirements. Road construction will be funded by FEMA while stream restoration projects may involve either NRCS or County funds. CM&I costs must be tracked and invoiced separately in addition to construction pay estimates.

Construction began in mid-2017 and has a 2018 expected completion date.

Project highlights

  • Construction Management and Inspection and Materials Testing for roadway and retaining wall reconstruction
  • Four simultaneous projects addressing flood damage
  • Multiple funding sources
  • Work within a constrained mountainside corridor
  • Maintain a travel lane at all times
  • Comprehensive scheduling strategy
  • Extensive public involvement efforts
  • Numerous stakeholders
  • Coordination with owner’s design team, Colorado DOT, FEMA, NRCS/EWP, contractor(s) and subconsultants for stream restoration, additional CM/CI capacity and materials testing.