FLOOD08078

• Designation Number: 169
• County: Eagle
• Community: Unincorporated Eagle County
• Basin: Colorado Mainstem
• Title: Flood Insurance Study - Eagle County, Colorado, Unincorporated Areas
• Date: 5/1/1980
• Designation Date: 12/1/1980
• Floodplain - Doc Type: Floodplain Report/Masterplan

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Total precipitation ranges from 40 to 50 inches per year on the
higher peaks to less than 12 inches per year near the Town of
Gypsum. From 20 to 30 inches per year is normal for areas at
elevations of 8,000 feet to 10,000 feet. At the lower elevations,
such as at the Town of Gypsum (6300 feet), and at higher elevations,
between the Eagle and Colorado Rivers, 50 percent or less of the
total annual precipitation occurs in the period of October to April.
In the higher mountainous areas in the eastern and southern portions
of the county, 7 percent of the total annual precipitation occurs
in that same time period. Major portions of the Eagle River and
Fryingpan River basins are at these higher elevations (Reference 3).

..

The Eagle River basin covers 57 percent, or 990 square miles, of
Eagle County and, excluding 14 square miles, is contained entirely
within the county. It drains in a northwesterly and westerly
direction, through the center of the county to the Town of Dotsero,
where it joins Colorado River.

Lower Eagle River is separated from Colorado River by Castle Peak
on the north, and from the Fryingpan River basin by Red Table Moun-
tain on the south. The topography is characterized by rolling hills
and a wide valley floor. Vegetation in the basin is less dense in
the lower reaches than in the upper reaches. Slopes in the lower
Eagle River basin range from 65 feet per mile near the Town of Avon
to 40 feet per mile near the Town of Gypsum. It averages approxi-
mately 22 miles wide, is 27 miles long, and has a drainage area of
584 square miles. Elevations vary from 11,785 feet at Red Table
Mountain to 6,120 feet at the mouth of the river.

The upper Eagle River basin, which runs from just above Gore Creek
to the Continental Divide, is oriented toward the northwest and is
bounded on the west by the Sawatch Range. The southern Gore Range
separates it from Gore Creek basin on the east. The high point in
the basin is Mount of the Holy Cross with an elevation of 14,005
feet. The upper portion is open, rolling terrain, in the lower
reach, near the Town of Minturn, there are steep mountain walls.
The basin is approximately 11 miles wide, 19 miles long, and has a
drainage area of 260 square miles just below Minturn. Slopes range
from 500 feet per mile on some smaller streams at higher elevations
to 65 feet per mile in the study area near the Town of Minturn.

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REVISED: 1/25/83