WSP01174

• File Number: 8449.900
• Description: South Platte Projects - Bear Creek
• State: CO
• Basin: South Platte
• Date: 1/1/1968
• Author: USACOE
• Title: Bear Creek Basin, South Platte River and Tributaries, Colorado, Wyoming and Nebraska - Letter from the Secretary of the Army
• Water Supply Pro - Doc Type: Publication

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River through the central part of Denver, and in areas of prospective
future metropolitan expansion north of Denver.

f, Summary 0 The Bear Creek drainage basin of 262 square miles
represents 66 percent of the remaining drainage area of the South
Platte River basin above central Denver which is not subject to control
by the existing Cherry Creek Dam and the authorized Chatfield Dam and
Reservoir project. The Bear Creek drainage area also represents
approximately 18 percent of the uncontrolled drainage area above
Brightcm, Colorado, the northern limits of metropolitan Denver.
Because of its potential for producing flash floods at high velocities
the flood damage potential from Bear Creek is analogous to that caused
by the flood from Plum Creek which staggered metropolitan Denver on
16 June 1966. Moreover, with the continuing urban growth anticipated
in the Bear Creek valley and the metropolitan environs on the South
Platte River north of Denver, the magnitude of the flood damage
potential of Bear Creek floods is expected to increase significantly
in future years in spite of local efforts to control encroachments
into flood hazard areas. While it is expected that local efforts to
control encroachments can be generally effective up to the 50-year
frequency flood hazard limits, the requisite optimum use of urban
valley lands in urban areas precludes control of encroachments
throughout the entire area of flood hazard as being economically
infeasible.

16. FLOOD DAMAGE EVAWATIONS

a. General. .'.l.ood damage poteutia.LB, were evaluated in detail for
the Bear Creek valley from Morrison to the mouth, and for the South
Platte River valley from the confluence of Bear Creek downstream to
the confluence of St. Vrain Creek. Flood damage potentials in the
upper basin were evaluated by general reconnaissance. The lower
Bear Creek valley was divided into two reaches on the basis of generally
uniform econanic and hydraulic characteristics. The effects of Bear
Creek floods on the South Platte River flood plain were evaluated and
summarized for three major reaches representing major distinctions in
the economic characteristics of the flood plain and the hydraulic
characteristics of the stream. The three major reaches of the South
Platte River included: (1) the 16.5 mile reach of central Denver from
Hampden Avenue to 84th Avenue; (2) the 12 mile metropolitan reach north
of Denver from 84th Avenue to Brighton; and (3) the 33 aile agricultural
reach from Brighton to the confluence of St. Vrain Creek. Flood damage
potentialS were evaluated for each reach on the basis of existing
condi tions of economic development, and on the basis of estimated future
levels of economic development for those urban reaches in which current
trends indicate substantial future growth. Flood damages were evaluated
separately for the agricultural reach and then included in the sununaries
of damages for the 84th Avenue to Brighton reach.

b. Estimates of flood damage potentials under existing conditions
of economic development and January 1966 price levels were based on the
types and values of properties located in flood-prone areas, on analyses
of previous floods, on delineation of areas subject to flooding and on

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