Phoenix’s Horse Mesa Dam Rock Debris Talus Stabilization Project was recently named a 2016 Public Works Project of the Year by the American Public Works Association (APWA). The project is being honored with APWA’s Project of the Year award in the Disaster or Emergency Construction/Repair category that include techniques and timing for safety, community relations, environmental protection, adverse conditions and additional considerations. For 2016, the team of winners includes the Salt River Project in Phoenix, AZ as the managing agency; DBA Construction Inc., as the primary contractor; and Geological Consultants Inc. as the primary consultant, who will be presented with the award during APWA’s 2016 PWX annual conference’s Awards Ceremony in Minneapolis, MN during August 28-31, 2016.
The APWA Public Works Projects of the Year awards are presented annually to promote excellence in the management and administration of public works projects, recognizing the alliance between the managing agency, contractor, consultant and their cooperative achievements. This year, APWA selected projects in five categories including Disaster/Emergency, Environment, Historical Restoration, Structures, and Transportation.
The Horse Mesa Dam Rock Debris Talus Stabilization project required stabilization of a large, migrating rock-fall debris talus deposit located in an extreme remote terrain at Salt River Project’s (SRP’s) Horse Mesa Dam (HMD). The emergency stabilization of the deposit was required to establish and maintain safe and reliable access to the dam, eliminate road clearing maintenance actions and costs, and provide additional parking and storage areas. The deposit was approximately 200 feet wide across the bottom and over 100 feet high.
The Salt River Project (SRP), as the owner, was unsure that the excavation could be completed, but the DBA Construction team developed a highly detailed execution plan for stabilization of the deposit to allow work and completion of the project. Besides the stabilization and excavation challenges, work was required in a limited area with a high potential for rock-fall within the work zone.
DBA proposed and used several methods to complete the project within budget and ahead of schedule. These methods allowed DBA to control natural movement of the deposit, reestablish and protect the roadway, maintain safe passage, preserve the environment, and prevent debris from accumulating within the river below during construction. Methods included retaining a Registered Geologist on the construction team to provide surveillance and geological monitoring, scaling the talus deposit removing loose debris, and installing a protective rock mesh drape system over the deposit to reduce the probability of rolling and sliding particles during work.
DBA’s challenges included working meticulously through each section of the project, with a modified design-build method, allowed the project to proceed without interruption and met every challenge along the way.
A combination of controlling the natural process with scaling, slope protection, and slope excavation innovations are what ultimately allowed the project to be built. These allowed completing the project one tight section at a time and provided SRP with a solution to the slope/rock-fall problems and addressed their budget concerns without sacrificing safety or quality.
For more information on the APWA 2016 Projects of the Year or for a complimentary PWX conference press pass, please contact APWA Media Relations and Communications Manager, Laura Bynum, [email protected], or call 202.218.6736.
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