FLOOD01357

• Designation Number: 107
• County: Jefferson
• Community: Unincorporated Jefferson County
• Stream Name: Green Mountain Area
• Title: FHAD - Green Mountain Area
• Date: 4/1/1978
• Designation Date: 7/11/1978
• Floodplain - Doc Type: Floodplain Report/Masterplan

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3. Station 78+00 to 48+00, Upstream Study Limits to DeFrame Way
(Sheets 11 & 12)

Above Beech Street, the channel consists of street flow along Ohio
Avenue, Coors Drive, Ohio Drive, and De Frame Way, The average slope through
the reach is 8%. The flood plain is generally contained within streets
and adjacent yard area, with some flow splitting in the street at Ohio
Drive and Beech Street.

The channel in this reach consists of a natural trapezoidal to
parabolic shaped channel in the eastern flanks of Green Mountain. The
flood peaks are contained within the channel area with shallow, high
velocity flow, The steep channel slopes (12%) result in erosion, debris
removal and cleanup flood hazards.

The flood hazards in the reach consist of erosion, debris removal

4, Station 48+00 to 0+00, DeFrame~to Alameda Parkway (Sheets 12 & 13)
Below Alkire Street, the channel consists of a trapezoidal shaped
section (300 LF), a 42" RCP storm sewer (gOO LF), and a parabol ic shaped
natural section (700 LF). The average channel slope is about 4.0%. The

and cleanup, interrupted traffic and services, deterioration of the

street, structural and content damage to the houses, missed work, general

inconvenience, and a low life hazard due to the high velocity and shallow

inlet structure to the 42" RCP at Ohio Avenue consists of a flared entrance

flow along Ohio Avenue.
C. Drainageway C
Drainageway C is a tributary to McIntyre Gulch at the Federal Center,
just north of Alameda Parkway. The channel drains the east flank of Green

section (43"H x 68"S HE-RCP) and the addition of a 54" RCP. The 54" RCP

follows south along Ohio Avenue diverting the storm runoff into Drainageway

Mountain.

B-1, The flood will be contained within the storm sewer and natural

channel area (with completion of improvements presently under construction).

The channel between Beech Street and Alkire Street consists of a

1. Station 24+00 to 0+00 and Station 128+40 to 84+00, U stream Stud
Limits to De Frame Wa Sheets 14, 15 & 16

chute is severely restricted by the fences and other domestic structures

The channel in this reach has been designated Drainageway C and

C-l (minor tributary). The channel consists of a natural V-shaped section

with an average slope of 10%. The channel passes through three small

depression areas (ponds), which collect some of the eroded material, The

flood plain is generally contained within the channel area with high

velocity flow,

concrete paved drainage chute between the houses. The slope of the chute

varies from about 4% to 7%, The drainageway crosses Alkire Street,

Arbutus Street and Beech Street with a concrete pan. The capacity of the

constructed across the chute. The flood plain is not contained within

the channel area, resulting in inundation of the residential property,
In addition, flow splitting to the south occurs along Ohio Avenue with
considerable flooding of the streets. There is also a potential for splitting
of the flows to the north at each of the cross streets along Ohio Avenue.

The flood hazards consist of erosion, debris removal and cleanup.

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