PROJ00048

• Contract/PO #: C153372
• Contractor Name: Hyannis Reservoir Company
• Water District: 0
• County: Jackson
• Bill Number: XB 99-999
• Loan Projects - Doc Type: Feasibility Study

Buffalo Creek

Buffalo Creek at the point of gaging drains an
area of 56.3 square miles. Records are available
from October, 1976, through fall of 1979. The
stream at this point has an average annual flow
rate of 4.3 cfs based on the three years of record.
Maximum discharge of 92 cfs occurred on June 8,
1979, with a minimum rate of 0,04 cfs occurring on
May 1, 1978. Forty-eight percent of the runoff
occurs during the months of May through August.
However, records show that during the years 1976-
1978, the summer flow rate often dropped below the
winter mean as a result of irrigation, a common
problem in measuring flow rates in North Park.

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Grizzly Creek, near Spicer, Colorado

Here Grizzly Creek drains an area of 119 square
miles, including the Hyannis site. Records are
available from October, 1976 through September, 1979,
at which time readings were discontinued. The
stream at this point has an average annual flow
rate of 61 cfs based on the three recorded years.
Maximum discharge of 864 cfs occurred on May 19, 1979,
with a minimum of 1.2 cfs occurring on September 18-
20, 1977. Eighty-one percent of the runoff occurs
during summer months.

Little Grizzly above Coalmont, Colorado

The Little Grizzly drains an area of 35.4 square
miles east of the Park Range. Again, records are
available for three years from October, 1976 to
September, 1979, at which time recording was dis-
continued. The stream has an annual flow rate of
29 cfs based on the three recorded years. Maximum
discharge was 394 cfs and occurred on May 28, 1979.
The rate of minimum discharge was Janua~y 9, 1977,
with a rate of 1.2 cfs. Seventy-five percent of
the runoff occurs during summer months.

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Of the three years available, the year 1978-79 was
a 'wet' year, while 1976-1977 was an extremely dry year.
Using this information, a ratio of wet to dry year
flows can be constructed (Figure 2).

The gaging station most nearly approximating flows
for Arapahoe Creek would be the Grizzly Creek station
near Spicer, just downstream from the outlet of
Arapahoe Creek. Flow records included one year, 1976-
1977, in which less than 20 percent of the normal
snowfall occurred, resulting in an almost snow-free
winter. The three year period ~,lso included an above
average runoff vear, 1978-1979. Using this data in
conjunction wit' the one year of Arapahoe Creek data,

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