T
he September 2013 flood
in Colorado devastated the
northern Front Range, causing
widespread damage to critical
infrastructure and transportation
networks. Hundreds of miles of roads
were washed out, cutting off access
to many small mountain towns.
Damage to homes and property was
widespread across the region.
The flooding was especially
devastating in many mountain
corridors north of Denver, including
the Big Thompson River canyon,
where about 12 miles of the U.S.
Highway 34 roadway embankment
were destroyed, homes were washed
out, and two lives were lost. The
highway links Estes Park and Rocky
Mountain National Park to Loveland,
Colorado, and the rest of Colorado’s
Front Range. Repairing this main
artery was essential for tourism,
businesses, and residents.
“We had 12 miles of complete
erosion of the river, complete
destruction of the roadway,”
explained Will deRosset, a hydraulics
engineer with Ayres Associates, the
firm responsible for river hydraulics in
the transportation project.
As a result, the Colorado
Department of Transportation (CDOT)
assembled a multi-faceted team of
consultants to design a permanent
repair for the highway, with the
goal of establishing resiliency of the
roadway into the future.
“The objective of the project was to
remove and replace the emergency
access that was established after the
flood in such a way that we integrated
the needs of the river with the needs
of the transportation corridor and of
the local residents,” deRosset said.
MANY MOVING PARTS
Jacobs Engineering Group, an
international engineering firm with
an office in Denver, led the design
team. Jacobs’ team comprised several
subconsultants, including Ayres
Associates, which provided the scour
evaluations for five access bridges,
embankment protection design for 15
miles of the highway, and conceptual
countermeasure design for several
high-damage areas.
While a massive roadway project
such as this one typically centers
around the roadway design itself,
in the case of the U.S. 34 project,
hydraulic engineering steered the
project, said Steven Humphrey, a
senior project engineer at Muller
Engineering Company who served as
CDOT’s assistant project director for
the U.S. 34 project and was charged
with the overall management of the
project.
“This project was unique in that
most of the time the roadway design
drives a project. In this project, the
river design drove the overall roadway
design,” Humphrey said. “It flipped
your typical transportation project
upside down.”
Hydraulic analysis was a critical
component of the project because
of the widespread destruction of
the highway embankment as well as
AyresAssociates.com
│15