FLOOD03938

• County: Jefferson
• Community: Lakewood
• Stream Name: McIntyre Gulch
• Basin: South Platte
• Title: Flood Hazard Area Delineation
• Date: 10/1/1977
• Prepared For: Lakewood
• Prepared By: UDFCD
• Contract/PO #: &&
• Floodplain - Doc Type: Floodplain Report/Masterplan

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Sheets 6, 7, and 8: West Boundary of the F.C. to R-1 school boundary
(sta 173+50 to 91+30);

The channel is crossed by Garrison Street with an 18'S x 16'H twin
tee bridge (scheduled for construction during this study, and therefore
considered an "existing drainage facility"), which has capacity to pass the
100 year flood. The channel is also crossed by Holland Street with two
48" CMP's, which is inadequate to pass a minor flood.

The channel in this reach consists of a deeply incised trapezoidal

shaped channel with minor meandering. The average slope is 1.9%. The

flood plain is generally contained within the channel with high velocity

flow, except where the flood water overtops the stream crossings for the

Agricultural Ditch, 7th Street, and Pierson Street within the F.C. As a

result of the overtopping at the railroad crossing, the area along Main

Street is subject to shallow flooding during the 10 year and 100 year

floods.

The 100 year flood plain is generally contained within the channel
and overbank area, except for the area near Holland Street, where severe
street overtopping and shallow flooding occur. The flow velocities in the
main channel are very high, but are moderate in the overbank area. The
development in the reach consists of single family residential with provisions
for raising livestock.

The channel is crossed by Kipling Street (18'S x 12'H RCBC) with
capacity for the 100 year flood; Main Street (15'S x 14'H RCBC) with
capacity for the 100 year flood; the Agricultural Ditch (12.5'S x 11'H RCBC)
with capacity less than the 10 year flood; 7th Avenue (120" CMP), with
capacity less than the 10 year flood; and Pierson Street (120" CMP) with
capacity for the 10 year flood.
The potential flood hazards consist of erosion, interrupted traffic
and services, and damage to the Agricultural Ditch.

The potential flood hazards in this reach consist of erosion, residential
inundation, interrupted traffic and services, and loss of livestock. Since
Holland Street is one of the major accesses to the property in the area,
the severe overtopping of the street will create an emergency vehicle hazard.
Sheets 9 and 10: Garrison Street to Carr Street (sta 74+00 to 32+30);
The channel in this reach varies from a fairly broad parabolic shape
to a very narrow, incised trapezoidal shaped channel. Throughout most of
the reach, the sides of the channel are very steep and are eroded and sloughed.
Considerable obstructions occur in the floodway, including brush, debris,
fences, utility poles, and foot bridges. Various attempts have been made
by the homeowners to stabilize the banks, including small retaining walls
constructed from concrete, fences, gabions, and other miscellaneous material.
The average channel slope in the reach is about 1.2%. The channel is crossed
by Carr Street in a 15'S x 12'H bridge, with capacity to pass floods with
a frequency up to 10 years and by Meadowlark Drive in an 8' x 8' RCBC with

Sheet 9: R-1 School Boundary to Garrison Street (sta 91+30 to 74+00);
The main channel in the reach varies from a parabolic shape to an
irregular trapezoidal-shaped section with varying amounts of overbank flow
areas. A portion of the banks of the main channel just above Garrison Street
have been concrete or gunite lined. The channel ,meanders moderately
throughout most of the reach, but has two approximately 900 bends near the
school property. A moderate amount of obstructions occur in the floodway,
including brush, debris, a foot bridge, fences, and some sheds. The average
channel slope in the reach is about 1.5%.

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