In Montezuma County, Carlo Citto is a world away from his native Italy. But the Boulder-based engineer looked right at home Thursday working on the McElmo Creek Flume.
Citto was busy testing the flume’s concrete and steel supports for weaknesses. Local advocates want to restore it to a more intact state, but first they need a structural assessment to ensure it won’t sink or collapse after the restoration.
Using a pachometer, Citto found the location of steel beams encased in concrete, then used an ultrasonic gauge to measure the steel’s thickness.
Crumbling, flaky concrete is usually a sign something is amiss inside.
“Corrosion expands steel up to 7-10 times the original size, and it pulls the face (of the concrete) apart,” Citto said.
When intact, the flume resembled an elongated barrel sawed in half, about 10 feet in diameter. Curved pieces of wood, called staves, were bound together with steel hoops and sealed with creosote to stop water from leaking. Irrigation water flowing through the flume caused the wood to expand, tightening the seams.
Concrete abutments added in the 1950s anchor McElmo Flume to each side of the arroyo near the Montezuma County Fairgrounds.
Any restoration work will be designed for longevity — at least 50 years — and minimal maintenance, said engineer Ron Anthony. The staves could be spaced out a little, allowing gaps for rain water and snow to drain. Vegetation and other debris should be removed from the creek bed about every five years, he added, to stop water collecting around the flume’s foundations.
Last July, Anthony studied the condition of the flume’s wood beams, planks and staves. Most of it is Douglas fir, with some Ponderosa pine. Two weeks later, researchers from the University of Colorado created a three-dimensional model with laser scanning.
Linda Towle, chairwoman of the Cortez Historic Preservation Board, thinks the flume is worth saving because water infrastructure shaped Montezuma County into what it is today.
“Cortez wouldn’t be here if the water delivery system wasn’t developed in the late 1800s,” Towle said. “There was no railroad, no river (through the center of town). It allowed agriculture to take root, and the city grew.”
The flume’s rickety state gives the project a “greater sense of urgency,” Anthony said. “It’s not the type of structure we can (address) in 10 or 15 years. By then it won’t be recoverable.”
James Dietrich, the county’s community services director, believes restoration is a worthy endeavor.
“It’s great to save parts of Montezuma County’s heritage. (The flume) is a small piece of the pie. We have a chance to capitalize on it,” he said.
Originally, Montezuma Valley Irrigation Company’s 150-mile ditch network contained 104 flumes. Using gravity, the ditches carried precious irrigation water from the Dolores River to farmers as far south as Towaoc. The route had to be carefully graded — too flat and the water would stagnate, too steep and it might escape over the edges at turns. The system was abandoned in the early 1990s after McPhee Reservoir filled.