From The Aspen Times (Scott Condon):
Bill McCormick, chief of dam safety for the water resources division, said the agency worked with Colorado Parks and Wildlife, the reservoir owner, to determine the source of water that was saturating a hillside beneath the reservoir and above Two Rivers Road. The water isn’t leaking from the dam, he said, but water is saturating the hillside when the reservoir is full.
“It’s not a dam-safety issue, but it is a public-safety issue,” McCormick said.
The hillside got so saturated the weekend of April 18 and 19 that mud and debris sloughed onto Two Rivers Road. The town of Basalt had to use heavy equipment to remove the debris. The water resources division and wildlife division came up with a plan to determine the source of the water. Lake Christine’s water level was lowered and increased throughout the summer to gauge the effect on the seepage, according to Perry Will, area wildlife manager for Colorado Parks and Wildlife. He said Basalt Mountain is riddled with natural springs, including some in the area of Lake Christine. The springs continued flowing even when the reservoir was at its lowest level, he said.
“The dam is fine,” McCormick said. The test established that water seeps into the surrounding terrain when water is above a certain level. That makes the hillside unstable and creates the potential for slides that could endanger people traveling on the road below, McCormick said.
The water resources division hasn’t established yet what level of water is allowable in Lake Christine. The seepage appears to occur when the reservoir’s water level is above 9 feet, or about 10 acre-feet, according to Erin Gleason, a dam safety engineer in Glenwood Springs for the Division of Water Resources. The normal storage when full is about 15 feet high and 30 acre-feet, she said.
The division needs to collect more information before formally issuing the water restriction, Gleason said.