PROJ00223

• Contract/PO #: C153723
• Contractor Name: Orchard Mesa Irrigation District
• Contract Type: Loan
• Water District: 0
• County: Mesa
• Bill Number: HB 95-1155
• Loan Projects - Doc Type: Feasibility Study

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GEOGRAPHICAL INFORMATION

L Climate

The Grand Valley is classified as an arid region and has an average annual
rainfall of 8,4 inches at the National Oceanic and Atmospheric Administration
station at Walker Field near Grand Junction, Snows are light, averaging 22
inches for the season, and they seldom remain on the ground for long periods
of time, The low precipitation in the Grand Valley amounts to only about
0.70 acre-feet per acre, per year. Temperatures in the valley range from -
230F. to 1050F. These extremes are rare, and average temperatures are
moderate, Winds are light in the valley, but some cold air becomes trapped
by temperature inversions and causes extended cold spells during the winter
months, Circulating winds offer protection against frost damage to the fruit in
the Orchard Mesa portions of the valley by preventing the settling of the cool
air in the trees. The frost-free period averages 191 days with a range between
151 and 233 days,

2. Topography and Soils

Orchard Mesa Project lands are on a gentle sloping erosional terrace or bench
above the present Colorado River. Mancos shale of the Cretaceous age is the
bedrock and is mantled by stream deposited gravels which are overlaid by
reddish-brown, light clay, loamy soil. This over-burden of transported soils is
deposited on an uneven eroded surface of shale, but generally, the soil depth
decreases from the edge of the river escarpment south to the shale hills that
border the bench land. Along the southern edge of the area some residual soil
is found. The average elevation of the District is 4,850 feet

Because of its location above the river level, water must be pumped from the
supply canal into the District's two main distribution canals. The west end of
the District is crossed by several deep water courses, requiring installation of
inverted siphons and tunnels to maintain gravity flow in the distribution canals.

3, Land Use

Before the advent of irrigation, Orchard Mesa was a saltbush desert, suitable
only for seasonal grazing, Much of the surrounding lands to the south are still
in their natural state, Estimated carrying capacity of the desert land is 1 AUM
on 30 to 40 acres,

Lands within the District can be subdivided into four categories: 1) irrigated
croplands and pasture, 2) non-irrigated, potential cropland either idle, fallow or
dry pasture, 3) farmstead and rural areas unsuitable for cultivation, such as

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