FLOOD06098

• Designation Number: 84
• County: Adams
• Community: Unincorporated Adams County
• Stream Name: South Platte River
• Basin: South Platte
• Title: Flood Hazard Area Delineation - South Platte River, Adams County, CO
• Date: 9/1/1977
• Designation Date: 11/1/1977
• Floodplain - Doc Type: Floodplain Report/Masterplan

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7

The reservoir flood storage capacity is 215,000
acre-feet. This reservoir will provide some ad-
ditional protection for the Denver metropolitan
area and the agricultural lands downstream from
the City. The level of protection diminishes
with downstream location.
3. The Bear Creek Dam and Lake, initiated in late
1973, is scheduled for completion in late 1979.
The dam is located on Bear Creek about eight
miles upstream from its confluence with the South
Platte River in Denver. The reservoir will have
a flood storage capacity of 26,000 acre-feet.

the State Highway Patrol, and road maintenance crews assist
in flood fighting and evacuating people from flooded areas.

The most effective means to reduce flood hazards, is to be
aware of such hazards and avoid them. Implementing flood
plain regulation practices will keep improvements out of
the flood plain and out of danger. Flood proofing will tend
to reduce damage to the existing buildings and structures
within the flood plain.

FLOOD RELATED STUDIES AND PERTINENT DATA

The National Oceanic and Atmospheric Administration (NOAA)
maintains year-round surveillance of weather and flood
conditions. Although intense cloudburst activity in the
general region can be forecast, such storms and resultant flooding
in specific small drainage areas cannot be predicted accurately,
and in any event, forecests would provide very little advance
warning.

There have been four previous flood plain studies of the South
Platte River, three of which were produced by the Omaha Dis-
trict, Corps of Engineers (Ref. 2,3, 4) and one by Gingery
Associates, Inc., for the Federal Insurance Administration,
(Ref. 1). Reports for the floods of June 1965 and May 1973
provided invaluable information on the actual extent of flood-
ing and high water marks. That information was used for com-
parison purposes for this report. The 1968 Corps of Engineers
Flood Plain Information Study described and updated hydrolo-
gic analysis of the South platte River, which included the ef-
fects of the June 1965 event (Ref. 2).

Throughout the study segment of the South Platte River in
Adams County, levees have also been constructed as a flood
protection measure. Photographic evidence of the South
Platte River floods of 1965 and 1973 (Ref. 3 and 4), how-
ever, show these levees to be ineffective. On certain seg-
ments of the South Platte River, records indicate that the
1965 and 1973 floods were of the 100-year magnitude or greater.

HYDROLOGIC AND HYDRAULIC DETERMINATIONS

HydrOlogic Analysis

Flood fighting and emergency evacuation plans are also factors
which can reduce the flood hazard. No formal plans for flood
fighting or emergency evacuation of people and personal property
from flood plain areas are known to have been prepared for
the South Platte River. However, during times of flooding,
agencies such as the local police, the sheriff's office,

The 100-year flood discharges used in this report were computed
and supplied by the Omaha District of the Corps of Engineers.
The flood discharges are represented to be characteristic of
1990 urbanized conditions. These discharges are slightly greater
v than those used in the Adams County Flood Insurance Study. The
discharges used in the FIA study were considered preliminary by