PROJ00441

• Contract/PO #: C153459
• 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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The assumption was made that the distribution of average monthly flows in

the historical record would remain unchanged in the augmented record. The

augmented record of monthly inflows was then computed by multiplying the

augmented annual values by the percentage of the historical mean value

calculated for each individual month. The historical mean values and

percentages used are shown in Table 5-1.

5.4 GENERATION OF SYNTHETIC INFLOW RECORD FOR CBT PROJECT

A 1000-yr synthetic record of CBT inflows was generated using the same
procedures described earlier in Section 4.3. As a matter of consistency,
only the augmented record of CBT inflows from 1927 to 1984 were used as
this period of record was used for the generation of synthetic Big Thompson
River native flows. The generation process reproduced the statistics of
historic CBT inflows quite closely in most months, although mean flow
values are quite high in comparison to historic values for the months of
March, September, and October. Consequently, the synthetic record will
often over-estimate inflows to the CBT during those months. As shown
earlier in Table 5-1, however, the combined historic average inflow of
these three months is less than six percent of the annual average. This
fact reduces significantly the impact on annual inflow volumes of
overestimates in March, September and October. On an annual basis, the
mean flow value of the generated record is within two percent of the
historic average. Table 5-2 presents the monthly and seasonal comparison
of synthetic versus historic statistics for inflows to the CBT. This
degree of accuracy is consistent with the later use of this data.
Additional details concerning this effort may be found in the Technical
Appendix.

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