FLOOD01280

• Designation Number: 93
• County: Jefferson
• Community: Lakewood
• Stream Name: McIntyre Gulch
• Title: Flood Hazard Area Delineation - McIntyre Gulch, Lakewood, CO
• Date: 10/1/1977
• Designation Date: 1/1/1978
• Floodplain - Doc Type: Floodplain Report/Masterplan

I
I
1
I
I
I
I
I
I
I
I
I
I
I
I
1
I
I
1

CHAPTER V
~LOOD HAZARD AREA DELINEATION

entrances to the small shopping center (4 - 48" RCP each crossing) with
capacity less than the 10 year flood.

The potential flood hazards in this reach consist of erosion, cOlllT1lercial

The 100 year flood plain and the 100 year water surface for the future
development condition flood is presented on sheets 3 to 14 in the Appendix.
In addition, the 10 year flood water surface profile is also shown. The
flood plains have been mapped from the confluence (sta 0+0) to above Young-
field Street along Alameda Parkway (sta 238+00), from the west boundary of
the Federal Center (F.C.) to Union Blvd. along the North Branch of McIntyre
Gulch, and from Moore Street to Union Blvd. along Alameda Avenue. A descrip-
tion of the flood hazards and channel conditions for the various reaches is

property inundation, and interrupted traffic and services. The separation

of the flows from the main channel by the inadequate street crossings also

increases the flood hazards outside of the main channel area. The problems

in this reach are to be addressed further by the City of Lakewood and the

U.D. & F.C.D. in the Green Mountain Major Drainageway Planning Study currently

underway.

Sheet 5: North Side of Alameda Parkway to the West Boundary of the F.C.
(sta 186+00 to 173+50);

presented below.
Sheets 3, 4, 5: Study Limits to Taft Street (sta 238+00 to 186+00);
The channel in this reach is trapezoidal shaped with check drops and an
average slope of 3.8%. The channel generally has adequate capacity to carry
the 100 year flood, however, severe street overtopping occurs at each of the
culvert crossings with subsequent separation of the flows from the main
channel. As a result of the flow splitting along Alameda Parkway, the
frontage road and the commercial area south of Alameda Parkway is subject
to shallow flooding during the 10 and 100 year flood.
The channel is crossed by Youngfield Street (4 - 63" x 40" CMPA) with
capacity less than the 10 year flood; by Xenon Street (15'S x 3'H RCBC) with
capacity less than the 10 year flood; by Center Avenue (10'S x 5.5'H ReBC)
with capacity for the 10 year flood; by the Green Mountain Shopping Center
entrance (10'S x 6'H RCBC) with capacity for the 10 year flood; by Union
Blvd. (4 - 42" RCP) with capacity for the 5 year flood; and by three

The channel in this reach consists of a rectangular concrete-lined

channel with check drops and a grass-lined trapezoidal channel. The channel

has adequate capacity to carry the 100 year flood. However, the fence

crossing the channel near Alameda Parkway collects significant amounts of

debris and, therefore, could severely limit the channel capacity with

resultant overtopping of the south bank and flooding in the G.S.A. warehouse

area.

The Welch Ditch crosses the concrete-lined channel in a concrete flume.

The waterway opening for McIntyre Gulch is adequate to pass the 100 year

flood.

The potential flood hazards in this reach consist of erosion and flooding
of the G.S.A. warehouse area.

9