FLOOD09982

• County: Garfield
• Community: Battlement Mesa
• Stream Name: Colorado River
• Basin: Colorado Mainstem
• Title: Battlement Mesa Storm Drainage and Floodplain Study
• Date: 3/1/1975
• Prepared For: CWCB
• Prepared By: Frasier & Gingery, Inc.
• Floodplain - Doc Type: Floodplain Report/Masterplan

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Page Twelve
Battlement Mesa Development Stonn Drainage and Flood Plain Study

5. Erosion control measures must be taken in all open
channels.

6. Erosion control measures must be taken wherever
water discharges down the sides of escarpments or gully walls.

7. The lOa-year storm runoff values to be expected after
full c1.evelopment occurs are as shown on the Stonn Drainage
Analysis Map.

8. The general location of detention ponds, culverts,
open channels and other major drainage facilities is shown
on the Storm Drainage Analysis Map.

9. Detailed preliminary drainage plans must be completed
on each area as it is platted.

10. The P.U.D. Plan as submitted to the County conforms
to the recomrrendations and conclusions of the Storm Drainage
Analysis.

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PART '1'\'70 - FLOOD PLAIN STUDY, COLORADO RIVER

VIII. Hydrology

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Determination of a design discharge for the Colorado
River by normal hydrologic methods is virtually impossible
due to regulation of flows in the River by a series of major
storage reservoirs and irriqation diversions in the upper area
of the river. A considerable number of detailed studies have
been completed on the river by federal agencies. These
studies have heen reviewed and analyzed to select a design
discharge for the lOa-year or Intermediate Regional Flood.

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The two governmental publications most pertinent to the
Colorado River at the Grand Valley area are the "Flood Plain
Information Report, Colorado River at Rifle, Colorado," and
the "Flood Plain Information Report, Colorado River at Grand
Junction, Colorado." The tributary drainage basin of the
Colorado Rive~ at Rifle is 6,930 square miles; at Grand
Valley the drainage basin is 7,276 square miles; and at
Grand Junction, 8,900 square miles. The Intermediate
Regional Flood Discharge (lOa-year event) established by the
Corps of Engineers at Rifle is 45,100 cfs, or 6.5 cfs per
square mile. The Intermediate Regional Flood established at
Grand Junction is 65,000 cfs, or 7.1 cfs per square mile.

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Comparison of the tributary drainage basin areas at
Rifle and Grand Valley indicate that the basin at Grand
Valley is only 5% larger than the basin at Rifle. There are
no major storage facilities or diversions from or to the
Colorado River below Rifle that would significantly affect
the design discharge at Grand Valley.