PROJ00221

• Contract/PO #: FS0017X
• Contractor Name: Ouray, City of
• Contract Type: Loan
• Water District: 0
• County: Ouray
• Loan Projects - Doc Type: Feasibility Study

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1.0 Purpose and Need for Action

1.1 Proposed Action. The Corps of Engineers and the local sponsor, the city of
Ouray, propose to rehabilitate an existing streambank on Skyrocket Creek.

1.2 Need for Proposed Action. Since the city of Ouray, Colorado, was founded in
1875, periodic debris flows have damaged buildings, roads, water systemssn
sewer systems. Skyrocket Creek is one of eight creeks in the area whose flow~
directly affectK the city of Ouray. .

Debris flows occur when water falls large elevations, a 2,8~-foot elevation
drop in the case of Skyrocket Creek, and picks up and combinesflne silt and clay,
sand, gravel, boulders, and dislodged timber (Jochim, 1986). In'the Ouray area,
these flows usually occur in response to intense summer thunderstorms after a
period of several years during which debris accumulates at the base of the
hillslopes in the primary drainage channels.

In 1929, Ouray County rerouted Skyrocket Creek to the north to reduce the
risk to the Hot Springs Park (Figure 1). A new channel was blasted through the
bedrock on the north side of the creek, and a wooden diversion structure was built
across the original channel. This was done to protect the downstream highway
and city facilities from debris flows originating in the upstream watershed. In July
1981, a debris flow from Skyrocket Creek breached the diversion and inundated
the Hot Springs Park (Jochim, 1986).

In order to protect the downstream facilities consisting of U.S. Highway
550, the community's natural hot springs aquatics center, visitor center and
children's fishing pond, a 6-inch water line, and a 12-inch sewer collector line and
manholes, the current diversion needs to be replaced. The diversion elJ:rr~I~
consists of earth and rock fill in the natural bedrock drainage way, topped by
timbers that have been displaced. Remnants of cabling, chain link fencing, and
sawn timbers that once comprised a portion of the structure have toppled into the
downstream drainage way. If the structure is not replaced, the almost vertical
slope of the channel as it comes off the mountain will result in very fast and
dangerous water, mud, and debris flows for even moderate precipitation events.

1.3 Project location. Skyrocket Creek, an intermittent, tributary r,o 1\1e fl.v C"'rl1j
Uncompahgre River, is located immediately north Of~~.1:i~Of 5ur!lY; .::rne-~\~~s \)
Skyrocket Creek diversion is located on the left bank of the creek channel at an
elevation of about 8,000 feet. The creek channel drains an area of about 0.7
square mile.

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