FLOOD03181

• County: Weld
• Community: Greeley
• Stream Name: Cache La Poudre River
• Basin: South Platte
• Title: Master Floodway Plan
• Date: 8/1/1983
• Prepared For: Greeley, CWCB
• Prepared By: Simons Li & Associates Inc.
• Floodplain - Doc Type: Floodplain Report/Masterplan

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V.

DEVELOPMENT OF FLOODWAY IMPROVEMENT ALTERNATIVES

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Floodway improvement alternatives were developed to mitigate flooding and

sedimentation problems within the Greeley reach of the Cache la Poudre River.

The Greeley reach of the Cache la Poudre River was subdivided into six

reaches to allow comparisons of improvement alternatives. The reach locations

are as follows:

Table 3. Dredged Material Summary.

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Location

Annual Quantity
(tons)

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Reach 1. Ash Avenue to U.S. 85.

11th Avenue Bridge

125

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Reach 2. U.S. 85 to 8th Street.

Reach 3. 8th Street to 5th Street.

Between 8th Avenue and the
Union Pacific Railroad

600

Between 3rd and 4th Streets

750

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Reach 4. 5th Street to Union Pacific Railroad.

Reach 5. Union Pacific Railroad to 11th Avenue.

Between 5th Street and 8th Street

150

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Reach 6. 11th Avenue to City limits.

At U.S. 85 Bypass

1,000

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Preliminary alternatives were developed considering structural and non-

structural methods of flood control. Improvement alternatives considered

include the following:

Source:

City of Greeley records.

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1.

Maintain the existing condition.

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2.

Improved flood control levees (100-year capacity).

3.

Improved river crossings at 8th Street, 5th Street, and 6th Avenue.

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4.

Trapezoidal channel (50- and 100-year capacity).

5. Combination channel (100-year capacity).

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6.

Dredging to increase flow area.

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7. Combinations of the above.

A description of each alternative follows.

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Maintain the Existing Condition

This alternative requires no capital improvements. The existing floodway

as developed by the Federal Emergency Management Agency (FEMA) would require

adoption. Flooding damages would not be reduced. The annual dredging and

maintenance program would be continued.

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