Big Canyon Reservoir Rehabilitation Project
Owner: City of Newport Beach, California – Utilities Department
Location: Corona Del Mar, California
COMANCO Project Scope:
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45 mil rPP Chafer Strip (along reservoir slopes – 500,000 SF)
SS Grillages for Water Circulation Mixers
60 mil rPP Floating Cover System (covering the entire reservoir – 1,000,000 SF)
Access Hatches / Vents
Rainwater Collection / Removal System
The Big Canyon Reservoir covers 23 acres and is capable of holding 200 million gallons of potable water. Since its original construction in the early 1960’s, the uncovered reservoir had been plagued with poor water quality, airborne pollution, midge fly infestation, turbidity, taste and odor issues. COMANCO was contracted to install a complex Floating Cover System, designed by Tetra Tech, Inc., to protect and improve the quality of stored water for residents of Newport Beach (Orange County), California.
COMANCO’s installation schedule was an aggressive six month duration.
The detailed scope of COMANCO’s work included:
- Fabrication and installation of a 45 mil rPP (reinforced polypropylene) chafer geomembrane on the reservoir side slopes. The chafer strip was anchored at the top perimeter curb anchor utilizing stainless steel (SS) anchor bolts and a rope hem termination and at the toe of the reservoir slopes utilizing encapsulated SS batten with periodic anchor points along the reservoirs concrete floor.
- Fabrication and installation of heavy gauge structural SS grillages at each of the reservoirs corners to protect the floating cover from the large submersible jet mixers as water levels within the reservoir fluctuate.
- Fabrication and installation of a complete, ballast and float style, Floating Cover System, including:
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60 mil rPP floating cover (NSF approved material)
reinforced rainwater collection / ballast troughs
sand ballast tubes
closed cell foam floats
vacuum formed float caps
fabricated rPP fittings
SS access hatches with encapsulated foam float platforms
non-slip walkway paths
perimeter SS anchor batten termination with rope hem
- Installation of a rainwater collection and removal system
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perforated HDPE collection piping running through the rainwater / ballast troughs
fabricated sump cans with encapsulated float rings
canaflex rainwater discharge hoses
2” dia. x 8’ rainwater direction tubes
- Quality control testing by air inflation of the completed floating cover
Sufficient volume of air was pumped under the cover rapidly enough to lift the cover away from the emptied reservoir floor. This allowed quality control technicians and independent monitors to walk underneath the air inflated cover and visually check for defects and holes before final approval and commissioning.
COMANCO’s onsite activities began in May 2004 and were completed in September 2004 with a consistent crew of 18 experienced and skilled COMANCO craftsmen.
COMANCO’s experienced team completed the complex installation on time and under budget. The project owner was impressed with the professionalism of all company employees as well as the quality of the overall project.
Once put into service the cover “floats” on top of the fluctuating water level as potable water is distributed and replenished.
The City is now experiencing the many benefits of a covered reservoir:
- prevents airborne (wind blown) contaminants from entering the processed potable water, ready for distribution.
- prevents large volume evaporation often experienced in uncovered reservoirs
- eliminates the potential for algae bloom
- provides water security
- decreased cost of water treatment as consistent amounts of chemicals to treat stored water
- ease of use and low cost of maintenance
The American Society of Civil Engineers recognized the Big Canyon Reservoir Rehabilitation, Project Team with the “Project Achievement Award” in February 2005.