PROJ00533

• Contract/PO #: C153367
• Contractor Name: International Engineering Company
• Water District: 0
• County: Rio Blanco
• Bill Number: XB 99-999
• Loan Projects - Doc Type: Feasibility Study

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correlation where required. All yearly flows used in this study are for
calendar years.

Hydrologic Period
The water availability analysis for a water resources project at the
appraisal level of study requires the use of a hydrologic period which is
representative of long-term seasonal and annual variations. A reasonably
long period which includes both dry and wet years is normally used. The
severity of the low runoff years during this period is a controlling factor
in determining the firm water yield of a particular project.

To determine the appropriate period of record, the long-term record at the
gage near Meeker was summarized into monthly volumes and analyzed. No
adjustments were made for the development of irrigated agriculture over the
1901-1980 period. Most of the agricultural development occurred prior to
1940 and the last 40 years of record essentially include the effects of
diversion and return flows from those uses. The variations in annual runoff
volume of the White River at the gaging station near Meeker are summarized
in Table 11-3.

An analysis was made of the spring and summer runoff (April through August)
characteristics for the long-term records at the gage near Meeker. The
five-month discharge volume was computed for each year and an estimated
minimum base flow of 70 cfs was deducted. The remaining value represented
an adjusted runoff volume proportional to the snowmelt component of the
total basin flow. A frequency analysis was performed on these data to
estimate the recurrence interval of the dry-year events. The frequency of
recurrence for the four driest years on record is as follows:

Runoff Season Recurrence Interval
1977 160 Years
1934 84 Years
1966 26 Years
1954 20 Years

11-5