PROJ00156

• Contract/PO #: C153721
• Contractor Name: Lyons, Town of
• Contract Type: Loan
• Water District: 5
• County: Boulder
• Loan Projects - Doc Type: Feasibility Study

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24 hours (or 2,0 cfs for 12 hours), This volume converts to 1.983 acre-feet (at) for the same 24-
hour period, The water commissioner's data sheets are in Appendix A,

The Water Commissioner's data are used to estimate the Town's water rights over the water years
1991, 1992, 1993 and 1994, A water year (WY) is the 12-month period from the previous
November 1st to the current October 30th,

To obtain a rough estimate of the average annual yield of the Town's water supply, several
assumptions are made as follows, For the direct diversion right, the Town appears to have been
in priority for 194, 149, and 157 days, or an average of 167 days/year for the four years in Table
1. Yield would be: 1.0 cfs x 1.983 af/cfsd x 167 days/yr equals about 331 af/yr. as a rough
average, The average yield of 523 C-BT shares at 0,67 af/share is about 350 af/year, for a
combined total of 681 af of available yield in an average year. As shown in Table 2, current
usage is about 333 af/yr, about one-half of the average year yield available, Thus, the Town
currently has a (681/333 = 2,0) supply ratio for "average" year supply and demand conditions,

The adequacy of the current water supply essentially rests on two factors: optimum management
of the assets described above and the probability of annual yield, Determination of probable
annual yield is not within the scope of this report; it is dependent upon several random,=
operational and legal variables, To optimize management, however, the Town should carefully
review its exchange operations and its use of storage space in Button Rock Reservoir. Optimal
use of storage space in Button Rock Reservoir may increase the reliability of the water supply,

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< < The Town of Lyon has retained Jack Ross to work with RBD, INC. In this matter of
defining and optimizing Lyons' water resources. A summary of the report from the water
rights attorney goes here in the second draft. The report will be bound as an Appendix to
this report for reference. Some amendment or elaboration of the preceding text may be
required. A detailed listing of the Town's water rights, here or in the Appendix, is
appropriate. Several actions are being considered by the Town, including an exchange
agreement with the City of Longmont. The water commissioner, Bill Gambrell, is very
familiar with the disposition of water rights for Lyons and says he supports an exchange
arrangement, as has been practiced by Lyons for many years. > > >

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