PROJC01820 ‎(2)‎

• Contract/PO #: C150189
• Contractor Name: Larimer and Weld Irrigation Company, The
• Contract Type: Loan
• Water District: 2
• County: Weld
• Loan Projects - Doc Type: Feasibility Study

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structure that is located upstream of the service area of the canal. That design criterion is essential
to avoid any indication of intent to abandon any part of any water right. Beyond the protection
of direct flow rights, further design capacity considerations include possible additional flows from
reservoir deliveries, upslope tailwater, precipitation runoff, and delivery scheduling allowances.

An additional factor that has an influence on required hydraulic capacity of the canal is the carrier
function for water owned by shareholders. The most significant source of carried water is the
Colorado-Big Thompson (C-BT) Project. Approximately 95 shares of C-BT water, which have
typically accounted for 1/3 to 1/4 of annual deliveries; with daily carriage flow rates as high as
425 cfs in the past 10 years, are owned by ditch shareholders. Reservoir water from the big
Windsor Reservoir (delivered by exchange) has typically run from 1/4 to 1/3 of the amount of C-
BT water on an annual basis. Non-direct flows from nine other sources have also augmented flow
in the canal at various times in the most recent 15 years of record examined incident to this report.

Total water delivered through the Larimer & Weld system average approximately 90,000 acre-feet
per year.

NEED FOR THE PROJECT

The Larimer & Weld Ditch (Eaton Ditch) is typical of main supply canals used for irrigation in
Colorado. The canal is checked at particular locations to raise the level of the water in the canal
to allow discharge through headgates into lateral ditches or directly onto fields. Other control
structures consist of dams and diversion structures that control the ditch and direct the flow to
storage. Most of the check structures for the ditch have been replaced since 2001 with new
concrete structures with automatically controlled Obermeyer gates. Only one check structure on
the ditch, Finley Check, has not been replaced. This structure along with the Lake Lee Dam and
Big Windsor Inlet are the structures being considered for replacement.

The structures in Eaton Ditch have been in service since near the start of canal operations in the
late 1800's. Although various localized structural repairs or modifications had been done, no
canal control structures had been totally replaced until recently when twelve new automated checks
were constructed to replaced existing stoplog controlled structures. The new check structures have
automated, air operated gates that have demonstrated a significant potential for canal operational
improvements. In addition to the checks, the Lake Lee Dam and Big Windsor Inlet are concrete
control and conveyance structures that are in disrepair and have about reach obsolescence. With
failure of these two structures, the ditch company would have a difficult time operating the ditch
and would lose water that is normally stored in Big Windsor Reservoir.

EXISTING FACILITIES

The structures considered for replacement by the Larimer & Weld Irrigation Company are listed
in Table 1.

Larimer & Weld Feasibility Study
Lake Lee & Big Windsor - 03.043

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