FLOOD03822

• County: Jefferson
• Community: Lakewood, Golden
• Basin: South Platte
• Title: Flood Hazard Area Delineation
• Date: 4/1/1978
• Prepared For: Lakewood and Jefferson County
• Prepared By: UDFCD
• Contract/PO #: &&
• Floodplain - Doc Type: Floodplain Report/Masterplan

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by the National Guard for war-time maneuvers, was acquired by the Fair
Association and the County in the early 1950's. The earlier structures in
the Fairgrounds were primarily used for sales, but, with the development of
the area from rural to urban, the Fairgrounds evolved into a livestock show
and recreation area. The drainage problems in the basin are the result of
development in the lower basin area, without adequate drainage facilities.
The urbanization of Bear Creek tributary basins began in the early
1970's. The development is progressing most rapidly in the upper middle
portion of the basin. Although the erosion has been aggravated somewhat,
drainageways have been protected from encroachment by the recent
development,
C. Topographic and Geophysical Feat~res
The McIntyre Gulch portion of the study area has a west to east
aspect with the high point of the basin on the eastern edge of Green
Mountain at approximately an elevation of 6700. The low point of the
drainageways is at an elevation of 5710 near Union Boulevard, with a length
of 2.4 miles. The channel slopes range from 13% in the upper portion of
the basin to 3.4% near Union Blvd.
The Lakewood Gulch portion of the study area has a northeast aspect
with a high point of the basin on the northeastern slopes of Green
Mountain at approximately an elevation of 6600. The low point in the
drainageways is at an elevation of 5580 at Simms Street and Lakewood Gulch
with a length of 3.0 miles. The channel slopes range from 15% in the upper
basin to 2.0% near Lakewood Gulch.
The Lena Gulch portion of the study area has a northerly aspect with
the high point of the basin on the northern edge of Green Mountain at an

elevation of 6855 feet. The low point in the drainageways is at an elevation
of 5710 feet at Isabell Street and Lena Gulch, with a basin length of 2,8
miles. The channel slopes range from 7,6% in the upper basin to 1.9% near
Lena Gulch.
The Bear Creek portion of the study area has a southerly aspect.
The upper end of the basin lies at the top of Green Mountain at elevation
6855, and the lowest point in the drainageways near Bear Creek is at
elevation 5440. The basin length is approximately 6 miles and slopes vary
from 18% on the flanks of Green Mountain to 0.5% near Bear Creek.
The flanks of Green Mountain are relatively steep, and the storm
flows are carried off the mountain in narrow steep ravines. While the
upper portion of the mountain is currently, and can be expected to
remain, in open space, the storm flow velocities are very high, and the
water will carry considerable sediment. The erosion process is quite
active depending primarily upon frequency of significant rainfall.
The soils of the basin are derived from the underlying shales,
sandstones, and conglomerates of the Dawson Arkose, Green Mountain is
comprised of resistant members of the Green Mountain conglomerate and
the upper part of the Dawson, including some andesitic material and
volcanic tuff. The soils are generally a calcareous clay loam of relatively
low permeability. Along the banks of the drainageway, coarser layers of
predominantly sand and small gravel are found on an intermittent basis.
D. Present Land Use
The present land use in the McIntyre Gulch portion of the study area
consists of single family residential (26%), several large shopping center
areas (4%), multi -family residential (6%), and open space (26%), The basin

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