To continue that effort, the city recently completed construction of the new Skyrocket Creek diversion dam, to replace a former structure, which had failed a few years back.
The diversion dam will ensure that any unusual water, mud or debris flow will be diverted toward the north, away from the Ouray Hot Springs pool to the west, and away from the city, situated mostly south of the pool.
According to Ouray County’s 2008 mitigation plan, the history of fighting debris-laden floods goes back to flumes built in 1909 to route debris and water from Portland and Cascade creeks through the city.
While the Portland and Cascade flows are considered “high hazard” by the Colorado Geological survey, the flow from Skyrocket Creek is considered “very high hazard.”
Very high hazard, according to the county report “could include structural damage…large accumulations of debris being piled in and around buildings, trees being toppled or severely damaged and severe mud and water damage…and loss of life is possible.”
Luckily, it doesn’t happen very often. The first diversion on Skyrocket Creek was built in 1929 after the pool was wiped out – for the second time – by debris flows.
According to the county’s Multi-Hazard Mitigation Plan, at the time a notch was also carved in the hillside to direct flow to the present catchment basin to the north and along a drainage out to the Uncompahgre River.
The notch is still there, but over the years, the old cable and timber diversion dam deteriorated and finally was completely destroyed in August of 2005. According to the report, the new diversion dam will function much as the old one, but is made of poured concrete and was given a new design by McMillon Engineering of Ridgway.
City workers and a few temporary employees did the actual work, Ouray City Manager Patrick Rondinelli said, and it appears the project has come in under the $50,000 allocated by the city council for construction.
Besides protecting the pool and city structures, the diversion dam will provide protection since a major slide could also cut off U.S. Highway 550, the major route in and out of town, said Rondinelli.
“In the event of a major catastrophe, it is important to keep the highway open to support emergency response as well as a critical evacuation route,” he said.
Shortly after the first diversion dam was built in 1929, it had to be replaced because it failed and “a drift of debris 40 feet high” was deposited on the highway below, according to the county report.