Big Cottonwood Water Treatment Plant reconstructed after 40 years

June 18, 1998

The Big Cottonwood Water Treatment is being reconstructed after 40 years of continuous service.
Built in 1957, the Big Cottonwood Water Treatment Plant located at the mouth of Big Cottonwood Canyon is being reconstructed to bring the facility up to current seismic standards and to replace and upgrade the electrical, mechanical and chemical feeding equipment. Ellesworth-Peck Construction Company was awarded the construction contract with a low bid of $3,735,012 for the chemical building and $621,300 for the filtration building. The reconstruction of the chemical building is scheduled to be completed during the summer of 1998 and the filtration building a year later.

The water treatment plant treats a major water supply for Salt Lake City.  Since it was placed in operation in 1957, it has been in continuous operations for the past 40 years, treating over 300 billion gallons (921,000 acre-feet) of water or about 24 percent of the City's drinking water supply. This is nearly equivalent to nearly 3 times the amount of water contained in Jordanelle Reservoir located west if Heber City.

The Big Cottonwood Water Treatment Plant is a conventional treatment plant with chemical addition, rapid mixing, coagulation, sedimentation and filtration.  Chlorine is used to disinfect the water.  Treatment capacity was increased from 28 million gallons a day to 42 million gallons a day in the 1980s.

Construction workers install new chemical feeding equipment.
Like all of the City's treatment facilities, this plant is participating in the "EPA Partnership of Safe Water" and far exceeds federally required treatment standards. Treated water quality from this plant is excellent with the finished turbidity being below 0.1 NTUs, far below the drinking water standard of 0.5 NTUs.

The seismic up-grade required the removal of external walls to be replaced with reinforced new walls,  "While the plant was being reconstructed it also received a face-lift with new roof and paint colors to give the facility a modern appearance." said Florence Reynolds, Water Quality Administrator. Ken Hibbert, Plant Manager points out that as part of the construction, the plant will be fed from a new penstock installed by Utah Power to replace the old wooden flume that is located along the north side of the canyon. "The new piped penstock made it possible to eliminate the need to up-grade the creek-side intake structure, and will make it easier to bring the raw water supply into the plant when the power plant is out of service" said Hibbert.