Grand Canyon’s Transcanyon Waterline: Replacing 1960s Pipe and Moving the Intake

The Transcanyon Waterline runs next to Bright Angel Trail on the South Rim and over the Silver Bridge across the Colorado River, to reach Phantom Ranch and the North Rim (NPS).

On average the Grand Canyon's water pipeline suffers at least one break a month. Each costs about $25,000 to repair, and park crews reach it by trail or helicopter. During a break, inner canyon facilities north of Phantom Ranch have no drinking water, and Phantom Ranch, Indian Garden and the South Rim must live off stored water. The National Park Service (NPS) has spent years designing a replacement. This account, by NPS writer Lily Daniels, was written when the design was nearly done.

Why replace it

The 12.5-mile Transcanyon Waterline (TCWL) was built in the 1960s and has outlived its 30-year design life. A condition assessment in fiscal year 2014, with earlier corrosion studies, showed it needs replacing. The pipe is aluminum, which helps wear it down and cause frequent breaks. Aluminum was chosen because it is light for its size and so easier to haul into the canyon, but, as NPS civil engineer Chris Carpenter explains, lighter pipe resists high pressure less well than the cast iron, ductile iron, cement or PVC that most water systems use. A break typically runs along the pipe, and a repair means cutting out and replacing an 8-foot section. Breaks have interrupted water on average for three to five days and forced visitors, residents and commercial operators into stricter water conservation.

A sign at the start of Bright Angel Trail says the water stations at the Mile-and-a-Half and Three-Mile Rest Houses are off because of pipeline breaks (NPS).

How the water travels now

Gravity does much of the work. Water starts at Roaring Springs at 5,200 feet and runs down along the North Kaibab Trail through Phantom Ranch. It crosses the Colorado River at its lowest point, 2,400 feet, then climbs to the Indian Garden pump houses at 3,700 feet. From there it is pumped up 3,300 feet to the South Rim through a borehole section. The Roaring Springs intake carries about 190 million gallons of drinking water for over 6 million visitors and 2,500 residents in the Inner Canyon Corridor and South Rim developed area.

What the program includes

Superintendent Ed Keable said the park has long needed a more secure water system. The program is a modernization of the whole delivery system, not a pipe swap. It follows 10 years of tests, analyses and reviews to meet public health, state and federal standards, environmental laws and historic preservation policies, and a final design review with the Arizona Department of Environmental Quality, Arizona Public Service, commercial operators and park staff.

• About 3 miles of new pipe from Phantom Ranch to Indian Garden (soon to be renamed Havasupai Gardens), with water distribution there replaced as well.
• New water and electrical distribution at Phantom Ranch, plus a water intake and pumping station there.
• About 3 miles of upgraded electrical supply line from Indian Garden to Phantom Ranch.
• A water treatment plant at the South Rim, rated at 1 million gallons a day, and a smaller one at Phantom Ranch.
• Improvements along Bright Angel Trail at the Mile-and-a-Half and Three-Mile Rest Houses.

Support facilities come early. Upgrades to the park helibase are among the first parts of construction, with an auxiliary hangar and helicopter landing pad to keep routine and emergency operations running, plus a contractor support area with trailer hookups, parking and staging.

A new water source

Bright Angel Creek (NPS).

The studies led to a decision to move the intake to Bright Angel Creek near Phantom Ranch. The South Rim, Indian Garden and Phantom Ranch would then draw from the creek, while Roaring Springs would keep supplying the North Rim, Manzanita and Cottonwood. More streams and watersheds can feed the new intake, which adds resilience, and the shorter pipe drops the stretch north of Phantom Ranch known as "The Box," where failures are most frequent. Natural flow would return to Bright Angel Creek from Roaring Springs.

NPS engineers, consultants and U.S. Public Health officers weighed many pipe materials. They chose flex-steel pipe as a balance of weight, durability and strength. About 18,000 feet of 6-inch aluminum pipe between Indian Garden and Phantom Ranch will be replaced with 8-inch flex-steel pipe. The Phantom Ranch plant will serve about 80,000 visitors plus staff, who use about 4.1 to 4.5 million gallons a year, and will give better water pressure for fire sprinklers and standpipes.

The facilities are designed to meet International Dark Sky building standards, so the park keeps its status, and to blend with the historic structures and the landscape. Most materials and equipment will have to be flown by helicopter into remote work areas with limited communications.

Schedule

When the account was written, NPS expected to award a construction contract later that year. Work would begin in late 2022 with staging, logistical support and water treatment facilities on the South Rim, followed in 2023 by the inner canyon pipeline and other facilities, and replacement was expected to be finished in 2027.

Sources

• National Park Service, Designing a Water System for the Future, Grand Canyon National Park, by Lily Daniels; rewritten in hubnx's own words. Written as of the article, before the contract was awarded.