FLOOD02918

• County: Denver
• Community: Denver
• Stream Name: South Platte River
• Basin: South Platte
• Title: Estimation of Flood Depth-Damage Curves for Residential, Commercial and Industrial Properties in the Denver Region
• Date: 10/1/1977
• Prepared For: CWCB
• Prepared By: Wayne J. Grahm ‎(Master of Science Candidate at CSU)‎
• Floodplain - Doc Type: Educational/Technical/Reference Information

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URBAN DRAINAGE AND FLOOD CONTROL DISTRICT

Four different publications have been issued recently dealing with

benefit-cost analysis of urban drainage and flood control projects (Rice,

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March, 1974;

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Grigg, et aI, June, 1974; Grigg, et aI, July, 1975; Urban

Drainage and Flood Control District, February, 1977). The same basic

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methodology for computing flood damages were contained in all four pub li-

cations. Each illustrated the benefit-cost analysis methodology (including

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damage evaluation) by using the Little Dry Creek project, located in Douglas

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and Arapahoe Counties as an example.

The 1970 FIA depth-damage tables were presented in the earliest publication

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(Rice, March, 1974). It was recommended that the FIA depth-damage tables

be used for estimating residential and small business structure and contents

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damage until more specific data could be developed. In the same publication

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contents of residential structures in the Little Dry Creek flood plain were

valued at 50% of the structure value in lieu of more definite data. To obtain

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the value of commercial contents, a random sample of all commercial contents

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was made and the resultant average was assigned to all commercial outlets.

Structure value was considered to be assessed value divided by.3, because

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property, under Colorado Law, is assessed at 30% of actual value. It was also

recommended that when the flood water velocity exceeded eight feet per second

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that the velocity head be added to the static water elevation when using the

FIA depth-damage curves. Per acre flood damage values for varying flood

depths were also presented.

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The second publication (Grigg, et aI, June, 1974) was almost identical

to the first with regard to flood damage evaluation. It was stated that the

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FIA data is valid only for residential structures and that generalized curves

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