FLOOD08183

• County: Summit
• Community: Breckenridge
• Stream Name: Blue River
• Basin: Colorado Mainstem
• Title: Floodplain Information Breckenridge
• Date: 9/1/1974
• Prepared For: Summit County
• Prepared By: Leonard Rice Consulting Water Engineers, Inc.
• Floodplain - Doc Type: Floodplain Report/Masterplan

I
I
I
I
I
I
I
I
I \~'\, ,\
'}tL \
' b/"u<J:,-"
v-" to'
/, (\i

I ~v
I
I
t
I
I
I
I
I

-

I

~ v~ ),jq
\ ' \.'
, ,r 1, ~~ > _
\~\ 1.,.(.' A" ;U
Y dO \'':.
J,

The storm center for the 25-year event is centered above

Lehman Gulch and ,not above the reservoir~ In this manner, peak

flows on the Blue 'River for the e;ent is greater from Lehman

Gulch than out 6f the Tarn Reservoir~because of the reservoir's

~-
storage capability.

The Intermediate Regional peak flow for the Breckenridge
area into the Goose Pasture Tarn Reservoir has been determined

to be 2900 cfs. Because the flood storage characteristics of
the reservoir, the peak discharge of ~he Intermediate Regional
flow through the town of Breckenridge is only 950 cfs. A
reduction in the peak flows of the Standard Project Flood from
21,460 cfs to 8,240 cfs is attained by routing through the
reservoir. The outflow from the reservoir is greater than the
spillway capacity on the Standard Project Flood. A~ a result,~\
the dam ~ver topped and~w occurs across the entire,wi~ \
of the dam's axis. Because the storm centers are located above
~
the town of Breckenridge and are concentrated on the Blue River,J~
the slight increase in the discharge of the flood peak as it
passes through the town of Breckenridge and on down the Blue
~iver is attributed to the base snowmelt which is running off
--- 7 ~; ...-\'-1..-VtG
.

from the entire basin.

HAZARDS OF LARGE FLOODS

The amount and extent of damage caused by any flood depends
on the topography of the area flooded, depth 'and duration of
flooding, belocity of flow, rate of rise and developments in
the flood plain. An occurrence of an Intermediate Regional or
Standard Project Flood on streams in the study area at the
present time would result in inundation of vacant land adjacent
to the river, damage to residents, roads, streets, bridges and
public utilities and interruption of traffic. Flood water
flowing at high velocity and carrying floating debris would create
conditions hazardous to persons and vehicles attempting to cross
flooded areas. In general, flood waters three I or more feet deep;( _
-= ,...., C"e-
and flowing at a velocity of three or more feet per second could
I
easily sweep a person off his feet, thus creating a definite i
I
~