CT2016-1987 Approval Letter

• Contract/PO #: CT2016-1987
• Contractor Name: Fort Lyon Canal Company
• Contract Type: Grant/Loan Combo
• Loan Projects - Doc Type: Approval Letter

Fort Lyon Canal Company Agenda Item 23a
September 15-17, 2015 Board Meeting(Updated September 18, 2015)
Page 3 of 7
Adobe Creek Reservoir 25,425 AF 12/29/1908 11/8/1928
Horse Creek Reservoir 11,400 AF 8/15/1900 11/8/1928
Horse Creek Reservoir 15,487 AF 1/25/1906 11/8/1928
Horse Creek Reservoir 1,113 AF 6/12/1908 11/8/1928
Thurston Reservoir 1,515 AF 8/12/1889 4/8/1905
Annual diversions have ranged from about 57,000 to nearly 500,000 acre-feet, averaging out to 221,000
acre-feet for planning purposes. All direct flow water is routed through the Horse Creek Flume; Storage
water is diverted down the Storage Canal and into the Company's reservoirs.
Project Description
The goal of this Project is to restore the Company's flume to provide reliable future deliveries to
downstream users. The following alternatives were considered:
Alternative 1 - Do Nothing: This alternative was considered undesirable due to the critical nature
of the flume and the near total loss of service to all users downstream of the flume.
Alternative 2 - Slip Line Existing Flume In-place: This alternative would leave the existing flume
in place, slip lining the entire 392 foot length of the flume with either HOBAS (centrifugally cast,
glass-fiber-reinforced, polymer mortar) pipe, or 'h-inch-thicksteel steel pipe. Also included in this
alternative is repair work to the intake and outlet concrete structures.
Advantages to this alternate include lower construction costs, and less demotion work due to
reuse of the existing flume. Disadvantages include a reduced pipe capacity due to a resulting
smaller interior diameter in the resulting pipe flume, and the addition of additional support
structures to support the pipe (5 for steel, 17 for HOBAS) would reduce the flood flow capacity of
Horse Creek below the flume, making the flume more susceptible to damage during flooding
events. Working within the existing steel flume could also be a significant construction challenge
due to the poor condition of the existing flume. Costs for this alternative range from $1,936,000
for HOBAS Pipe to $2,169,000 for Steel Pipe.
Selected Alternative 3 - Replace Flume with New Steel Pipe Flume: This alternative consists of
removing the entire existing steel flume and its supports, and replacing it with a new 123-inch
diameter, 'h-inch-thick steel flume and new support structures.
The existing flume and its supports would be completely removed, and new concrete foundations
installed or existing concrete foundations rehabilitated. Also included in this alternative is repair
work to the intake and outlet concrete structures to address cracking and other structural issues,
as well as the installation of a new expansion joint.
The key advantages to this alternative are no reduction in flow capacity. Additionally steel will
not be affected by UV light and be less susceptible to wildland fire, and has a proven track record
of use in this application. Some disadvantages to this alternative include higher demolition costs
since the existing flume would be removed. The new steel flume is also expected to have higher
lining and coating maintenance costs in the future. The cost for this alternative is estimated at
$2,188,000.
Alternative 4 - Replace Flume with a New Concrete Flume: This alternative consists of
removing the entire existing steel flume and its supports, and replacing it with a 15-foot-
wide by 9-foot-high enclosed concrete flume. The new concrete flume would be supported
by seven new pier frames, mounted on new foundations.