Can a small reservoir in remote Southwest Colorado play a larger role to help meet the water demands of an increasingly water-strapped region?
The reservoir’s managers are hoping so, otherwise the dam faces possible demolition.
“To make it a viable structure, we’ve had to look for other partners,” said Trent Taylor, operator of Red Mesa Reservoir and a board member of the Red Mesa Reservoir and Ditch Co. “And we’re still plugging away at it; we’re just going to have to beat the bushes hard.”
Red Mesa Reservoir is a small 1,175-acre-foot storage body (nearby Long Hollow Dam, for reference, is about 5,400 acre-feet) that provides water to about 50 people in the notoriously arid western part of La Plata County, known as the Dryside.
The dam, historically known as Mormon Reservoir, was originally built in the early 1900s by members of the Church of Jesus Christ of Latter-day Saints, which used a “Fresno scrape,” a machine pulled by horses for building canals and ditches.
In 1911, a flood washed out the earthen dam, and it wasn’t until 1945 that the structure was rebuilt. Aside from minor improvements over the years, Red Mesa Reservoir, which sits about 20 miles southwest of Durango off La Plata Highway (Colorado Highway 140), has remained mostly unchanged.
Since at least the 1980s, however, Colorado’s Division of Water Resources has deemed the dam’s spillway (the structure used for overflows) inadequate to handle the waters of major floods.
In January 2018, the issue came to a head when the Division of Water Resources ordered Red Mesa Reservoir managers to complete improvements to the structure by 2024 or face demolition, while at the same time, prohibiting any water to be stored there until it was deemed safe.
In an effort to buy time, Red Mesa Reservoir managers spent $25,000 to expand the spillway, and in exchange, were allowed to keep water in the reservoir.
Red Mesa Reservoir, however, is still being held to a tight timeline to make permanent fixes.
Jordan Dimick, a senior engineer with SGM, the firm helping to draft construction plans, said final engineering designs and most of the permitting process must be completed by March 2021. Then, construction is scheduled to start in 2022 to meet the state’s imposed completion deadline of 2024.
But covering the costly price of the construction project is going to take ingenuity, Dimick said.
For the past two years, Red Mesa Reservoir managers have been selling the idea of enlarging the dam in an attempt to generate more interest, more stakeholders, and therefore, more funds toward the project.
Those exact details should be completed this month, Dimick said.
“Then we can sit down with interested stakeholders and have a model to show alternative sizes, how each party would benefit from enlargement and what those projects would cost,” he said.
The Division of Water Resources itself may have an interest in expanding Red Mesa Reservoir as a way to help meet the water compact with New Mexico by teaming up with Long Hollow Dam, which was built for that purpose.
Colorado Parks and Wildlife has shown interest in keeping water in the La Plata River for native fish when water isn’t flowing out of Long Hollow Dam during the non-compact season, which typically runs from December to February. And, Dimick said, the agency may want to add some recreational opportunities on the lake.
Taylor in 2018 estimated it would cost up to $9 million to bring the reservoir to standards. If improvements weren’t made, he said it would cost the state about $1.5 million to raze the dam.
Matt Gavin, a dam safety engineer for the Division of Water Resources, said rules and regulations for dam safety and construction in Colorado were recently revised, which should help cut down on the price of revamping Red Mesa Reservoir.
“The spillway design should significantly be less in cost with the new rules, and if they have an adequate warning system in place, they can design to a lesser standard than what’s required for high-hazard dams,” Gavin said.
Not many homes are below Red Mesa Reservoir or in the path of its potential floodway. And, the region has been so historically parched of precipitation, Taylor said the existing spillway has never been used.
It’s unclear how much the project, which may double the reservoir’s capacity, may cost, but it’s expected to be in the millions. But with the state’s revised rules, and partners within the region coming together to fund the project, it’s possible Red Mesa Reservoir may stand past 2024.
“The goal is to get to a win-win scenario where it helps a lot of folks,” Dimick said. “And then come up with funding mechanisms to get to that solution. We’re very optimistic where we are, but there’s still a lot of work to do.”
jromeo@durangoherald.com
