PROJ00106

• Contract/PO #: C153494
• Contractor Name: Loveland, City of
• Water District: 0
• County: Larimer
• Bill Number: XB 99-999
• Loan Projects - Doc Type: Feasibility Study

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3.2.3 CAPACITY CONSTRAINTS

The transmission capacity of the Dille Tunnel is approximately 400 cfs.

Historic flows from water years 1979 through 1985 were evaluated to assess

the available capacity. Those records showed that flow in the tunnel

during the irrigation season (i.e., April through October) averaged only 47

cfs and exceeded 300 cfs only four percent of the time. It was concluded

that the flow characteristics of the tunnel itself present an

insignificant, if any, constraint on use of that facility.

Capacity-constraint curves for each month were also prepared from similar
data for the CHFC. The observed historical flows, however, were increased
by the estimated quantity of Vindy Gap water that would be transported in
the CHFC prior to calculation of the flow duration characteristics. This
was necessary because the historic data base did not include delivery of
Vindy Gap water. The increased flows due to transport of this water were
estimated from the projected ownership and usage of Vindy Gap given in the
Vindy Gap EIS (VPRS, 1981).

Figures 3-2 through 3-5 illustrate the capacity constraint curves for the
months of June through September, respectively, developed for the CHFC.
These curves depict the percentage of time that the available capacity in
the canal is predicted to be less than or equal to a specified flow rate.
Separate curves are shown for the canal to the south of (before) and to the
north of (after) the siphon.

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The curves demonstrate that no capacity will be available to Loveland in
the CHFC the following percentages of time:
Before After
Month Siphon Siphon
June 1.8% 5.4%
July 9.4% 16.1%
August 0.0% 3.8%
September 0.0% 0.15%

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