WSP07965

• File Number: 8446
• Description: Cache La Poudre Project
• State: CO
• Basin: South Platte
• Water Division: 1
• Date: 7/1/1983
• Title: Cache La Poudre Project Study and Related Correspondence
• Water Supply Pro - Doc Type: Report/Study

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D. CLIMATE

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The topography of the Cache la Poudre River basin varies from alpine
tundra in the high mountain headwaters to relatively flat plains at the
confluence witp the South Platte River. This rapid variance, in conjunction
with the regions mid-latitude location, results in localized climatic
extremes.

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precipitation varies from over 25 inches per year in the high mountain
areas to 14.19 inches per year at Fort Collins, and 11.12 inches per year at
Greeley. Temperatures range from near arctic proportions in the high
mountains of the upper basin to maximums of over 1000 F in FOrt COllins and
Greeley. The mean annual temperatures are 48.1' F, at Fort Collins, 48.30 F,
at Greeley, and 35' F in the mountains.

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The climate of the upper basin is typical of the Colorado mountain
regime. Most of the precipitation occurs as fall and winter snowfall.
Average snowfalls exceed 100 inches per year in the high mountains decreasing
with elevation to about 48 inches per year at Fort Collins. Occasional
scattered summer thunderstorms contribute a small amount to the annual
runoff. Mountain valley agriculture, primarily hay and pasture, is limited by
a 90-day growing season.

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The climate of the lower basin is characterized by low annual precipi-
tation, low humidity, winds, and an abundance of sunshine. This, with a wide
range of temperatures, results in high rates of evaporation. The winters are
generally mild; however, short periods of sev,ere cold occur. There are
usually several heavy snowstorms during the wipter; however, snow does not
accumulate to a great degree in the lower basin. Spring and summer
precipitation usually occurs as thunderstorms, sometimes with strong winds and
hail.

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Precipitation in the lower basin is usually erratic and unevenly dis-
tributed, but is generally sufficient to support a light cover of native
grasses, shrubs, and some winter grains. The maximum monthly precipitation
usually occurs in May while the minimum usually occurs in the months of
December, January and February as light, dry snows. Successful farming is
almost wholly dependent on irrigation. The growing season in the lower basin
is from 175 to 185 days.

E. FISH & WILDLIFE RBSOOllCBS Y

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The upper Cache la Poudre Basin has a great abundance and variety of fish
and wildlife resources. A reason for the variety of species is the fact that

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Y The information for this section of the report was obtained from an
unpublished report prepared by the COlorado Division of wildlife in
December 1978, for the U.S. Forest Service.

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