FLOOD05793

• County: Boulder
• Community: Longmont
• Stream Name: Dry Creek
• Basin: South Platte
• Title: Technical Addendum Floodplain Information and Flood Control and Drainage Plan
• Date: 4/1/1980
• Prepared For: Boulder County
• Prepared By: Water Resource Consultants
• Floodplain - Doc Type: Floodplain Report/Masterplan

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FACTOR

GENERAL DESCRIPTION

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I. SURFACE ROUGHNESS

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2. VEGETATION

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3. CHANNEL IRREGULARITY

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4. CHANNEL ALIGNMENT

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5. OBSTRUCTIONS

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6. STAGE

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7. SEASONAL CHANGE

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TABLE-\
N-VALUE SELECTION FACTORS

Increasing the size of the grains of the
material forming the wetted perimeter gen-
erally increases the n-values.

Increasing the height and density of the
vegetation increases the n-values.

Abrupt irregularities in cross section SIze
and shape increases the n-values.

Sharp bends and severe meandering increases
the n~values.

Items that block the flow such as log jams
and bridge piers increase the n-values.

N-values generally decrease with increasing
depth.

N-values were selected for normal maximum
height and density of vegetation during the
flooding season.

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