Drought news: Drawdown of Wolford Mountain Reservoir an opportunity to inspect Ritschard Dam settling

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Here’s the release from the Colorado River District (Martha Moore):

The Colorado River District, which owns and operates Wolford Mountain Reservoir, will take advantage of this year’s drought and resulting low reservoir water levels to further monitor movement at Ritschard
Dam.

As with all earthen dams, Ritschard Dam was expected to settle over time. However, over its 16-year life, the dam has settled nearly two-feet, rather than the estimated one-foot. This year’s dry conditions require drawing the reservoir down lower than most years in order to meet contractual and environmental demands for the stored water. Previous monitoring data suggest the settling rate slows as water levels decline. A major drawdown of the reservoir this year will assist in further assessment of the situation.

“The dam is safe. There is no reason for concern over dam failure,” assures John Currier, chief engineer for the Colorado River District. “There are no leaks; the dam is solid. However, we need to determine the cause of continued settling,” added Currier.

About Wolford Mountain Reservoir:

Wolford Mountain Reservoir is located on Muddy Creek, five miles north of Kremmling. It stores 66,000 acre feet of water when full. The reservoir primarily provides water to west slope contract holders when their water rights would otherwise be called out by more senior water users on the Colorado River. Water is released from the reservoir to protect Western Slope water users and to substitute for water diverted by Denver Water at Dillon Reservoir in critically dry years.

Water releases from Wolford also benefit endangered fish in the Colorado River near Grand Junction to enhance flows in the spring time and in late summer during times of lower flows.

Wolford was built in cooperation with and financing from Denver Water and Northern Water, both Front Range transmountain water diverters.

More coverage from Drew Munro writing for the Summit Daily News. From the article:

“This year is a really good test,” John Currier told Kremmling Town Board members Wednesday night, explaining that the reservoir will be drawn down 30-35 feet below full by the end of October.

“The reservoir hasn’t been drawn down like this since 2002-2003,” he added.

Currier, chief engineer for the river district, was at the meeting along with other district representatives to allay rumors that Wolford Mountain is being drawn down to prevent it from failing and to present a progress report about the ongoing investigation into why the dam is moving.

He said the reason the reservoir will be drawn down so far this fall is that Denver Water, which holds a lease for 25,000 acre-feet of “substitution water” annually in the 66,000 acre-foot impoundment, will release all its water this year. That, and Colorado Parks and Wildlife will use another 6,000 acre-feet this fall to augment downstream flows for endangered fish, he said.

In a “normal” year, he said the reservoir is drawn down about 10 feet. When that occurs, he said monitoring instruments indicate the rate of settling slows substantially. What engineers will be looking at this fall is whether there is a point at which the settling slows further or stops as the water level falls.

More Wolford Mountain Reservoir coverage here and here.

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