C153835A Feasibility Study

• Contract/PO #: C153835A
• Contractor Name: Greeley and Loveland Irrigation Company
• Contract Type: Loan
• Water District: 3
• County: Weld
• Bill Number: HB 98-1189
• Loan Projects - Doc Type: Feasibility Study

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Chapter IV - Formulation of Alternatives

The alternatives are classified in two categories: 1) structural rehabilitation; and 2) non-
structural. The non-structural alternative is essentially a "do nothing" alternative leaving the existing
structure in place with no rehabilitation. Each alternative for the projects are described in detail in
the following sections.

There are three main structural components of this study: 1) canals; 2) dams and their
appurtenant structures; and 3) canal structures. Each component has different project focus and
goals. The existing canal system has been in operation since the turn of the century and is in need of
repair. Big Barnes Ditch and Greeley and Loveland Canal flow capacities have been limited over time
due to failing of the natural and concrete linings, urban encroachments, and canal crossings. The
canal alternatives include three considerations: 1) Protect the existing canal from failure at the present
flow capacity; 2) Restore the flow capacity of the existing canal by rehabilitating the system with
structural lining; and 3) Restore the canal system to its decreed water right by a combination of
structural lining, flow area enlargements and bridge transitions.

The SEO has notified the Company that several of their dams (Le. Horseshoe Dam, Boyd
Lake Dam, Equalizer Dam, Upper and Lower Hoffinan Dam and Westerdoll Dam) do not meet the
State's safety standards with respect to spillway capacity. Three approaches were studied for each
dam which include: 1) the use of an incremental damage analysis to minimize structural requirements
for enlarging the spillways; 2) increasing existing spillway capacity using fuseplug spillways, Labyrinth
weirs, or adding flood storage reservoir volume; and 3) dam overtopping protection using RCC, or
articulated mats.

There are three canal structures which have been in operation since the early 1900's. These

structures include the Lake Loveland North Outlet, Hubbs Check, and Oklahoma Check. These

structures have functioned well with the exception of the Lake Loveland North Outlet. The present

North Outlet structure restricts the flow due to inadequate gate capacity which should be replaced

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