FLOOD07478

• County: Denver
• County: Jefferson
• Community: Lakewood, Denver,
• Stream Name: Lakewood Gulch
• Basin: South Platte
• Title: Flood Hazard Area Delineation
• Date: 2/1/1979
• Prepared For: Lakewood, Denver, Jefferson County
• Prepared By: UDFCD
• Contract/PO #: &&
• Floodplain - Doc Type: Floodplain Report/Masterplan

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18

VII DESCRIPTION AND DELINEATION OF THE 100-YEAR FLOOD HAZARD

The 100-year Flood

Presented at the end of this Section are the Flood Hazard Area

Delineation (FHAD) Sheets illustrating the estimated extent of

flooding which would occur along Lakewood Gulch in the event

of a 100-year flood under the future condition of a fully

developed watershed. No records are available to indicate

whether or not floods of the magnitude described herein have

occurred on Lakewood Gulch. However, it is statistically indi-

cated that a rainfall equal to the 100-year storm described

herein will occur at some time. The hydrologic and hydraulic

analyses indicate that such a storm will generate the flood

depicted in this report. Table 5 represents a tabulation of

data relating to the anticipated flooding in a 100-year storm.

FHAD Sheets 3 through 23 illustrate the thalweg (valley bottom)

profile of the channel, the water surface elevations of the 10-

year and lOO-year floods, and the areas which would be inundated

by the lOO-year flood. Table 5 also presents data describing

the floodway along the channel.

W. 6th Avenue to Welch Street (Sheets 3, 4, 5)

The northerly right-of-way line of W. 6th Avenue is the westerly

limit of this report. In this reach, Lakewood Gulch crosses

W. 8th Avenue and Welch Ditch. Between W. 6th and W. 8th Avenues,

Lakewood Gulch is confined within the channel through a resi-

dential subdivision. The bridge carrying 8th Avenue over Lake-

wood Gulch is subject to inundation to a depth of .5 feet. The

resulting backwater on the south side of W. 8th Avenue does not

cause flooding of structures. There are no structures located

in the floodplain west of Welch Street. Welch Ditch crosses

Lakewood Gulch in an elevated flume. The bridge carrying the

flume is large enough to pass the lOO-year flood without causing

backwater. The culvert under Welch Street is too small to

carry the projected lOO-year flow. The backwater caused by the

culvert does not inundate any structures.

The remainder of the text of this Section presents descriptions

of flooding characteristics to supplement the FHAD Sheets. The

descriptions are keyed to the sheets as well as to geographical

locations.

Welch Street to Simms Street (Sheets 5, 6, 6A)

Between Welch Street and west of Van Gordon Street the 100-year

flow is carried within the main channel of Lakewood Gulch with-

out inundating any adjacent structures. The culvert under Van

Gordon Street causes a depth of overtopping of approximately

3 feet. A portion of the flow overtopping Van Gordon Street

splits off from the main course and flows north along Van Gordon

Street causing shallow indeterminate flooding of property east