FLOOD04245

• County: Mesa
• Community: Grand Junction
• Stream Name: Indian Wash
• Basin: Colorado Mainstem
• Title: Hydrologic Analysis Indian Wash
• Date: 1/1/1980
• Prepared For: FEMA
• Prepared By: MSM Consultants, Inc.
• Floodplain - Doc Type: Floodplain Report/Masterplan

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Major obstructions to the natural drainage of the
watershed include Interstate Highway 70, the Highline
Canal and the Grand Valley Canal. These structures cross
the watershed in an east-west direction.

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The Indian Wash watershed can be divided into two
distinct sub-basins. The major sub-basin which is
drained by Indian Wash includes the entire watershed
above the Highline Canal and approximately 60 percent of
the watershed south of the canal. The Highline Canal
acts as an obstruction to the drainage and intercepts the
runoff from 3.4 square miles of the watershed which it
diverts to Indian Wash. The second sub-basin is located
to the south of the Hi ghl i ne Cana 1 and to the eas t of
Indian Wash. The sub-basin is drained by an unnamed
channel tributary arbitrarily called the 29~ Road Channel
for identification in this report. The 29~ Road Channel
flows southerly from the Highline Canal to the Denver and
Rio Grande Western Railroad (D&RGW) tracks where it turns
southwestward to its confluence with Indian Wash just
upstream of the D&RGW bridge.

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The total watershed drainage area at the D&RGW bridge is
approximately 15.3 square miles. Of this area, 69
percent or 10.5 square miles lies above the Highline
Canal. The area above the lW-l retention dam measures
6.2 square miles or 41 percent of the total watershed
area. The contributing area of the 29~ Road Channel at
the mouth is approximately 1.9 square miles or 12 percent
of the total area.

The slope of Indian Wash north of
averages 2.5 percent and the slope
canal averages 0.5 percent.

the Highline Canal
downstream of the

The soils of the study area are composed primarily of
materials from the Mancos Shale and a Mesaverde
sandstone. These soils are characteristic of soils in
desert to semi-arid regions.

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Vegetation in the watershed is sparse, consisting of
greasewood, a salt-to levant shrub; salt brush, and sage
brush in the foothills, and pinon-juniper and hardy
grasses at the higher elevations. The primary land use
for the watershed is rangeland, but a significant amount
of the land below Interstate 70 is irrigated (Reference
1) .

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