WSP06290

• File Number: 8277.600.10
• Description: Big Sandy River Unit - Colorado River Salinity Control Program
• State: WY
• Basin: Colorado Mainstem
• Date: 5/1/1986
• Title: U.S.D.A. Selected Plan - Big Sandy River
• Water Supply Pro - Doc Type: Definite Plan Report

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TABLE 2-1

LAND OWNERSHIP, BIG SANDY RIVER WATERSHED, WYOMING

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Administration or Ownership Acres Percent
Bureau of Land Management 831,760 68
Forest Service 182,160 15
U.S. Bureau of Reclamation 108,880 9
Private 54,500 4
State 50,220 4
Total 1,227,520 100

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Climate

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The climate of the Eden-Farson area is classified as semiarid. The
essential feature of a semiarid climate is that the potential
evaporation from the soil surface and the vegetation exceeds the average
annual precipitation.

Precipitation ranges from 40 inches or more annually on the Wind
River Mountain Range to about 7 inches annually for the irrigated area
in Eden Valley. Due to low annual precipitation in the farmland area,
irrigation is essential. Peak precipitation months are April, May, and
June, The average monthly precipitation at Farson varies form 0.32 to
0.96 inches.

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While snowfall may occur as early as September and as late as July,
the common period of snowfall is from October to May. Rock Springs,
located 40 miles south of Farson, averages 44.6 inches of snow annually,
although snowfall in excess of 80 inches has been recorded. The snow
cover generally remains on the ground during the winter months.

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The high altitude and relative low humidity cause considerable
variance in temperatures. The mean annual temperature is 370F with a
recorded extreme range of -550F to 950F. Freezing temperatures have
occurred in every month of the year. There is only a fifty-fifty chance
that the growing season will be as long as 85 days (assuming 280F
threshold temperature).

OJC~83

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