FLOOD07039

• County: Summit
• Community: Breckenridge
• Stream Name: Blue River
• Basin: Colorado Mainstem
• Title: Breckenridge Community File
• Date: 1/1/2001
• Prepared For: CWCB
• Prepared By: CWCB
• Floodplain - Doc Type: Community File

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PRINCIPALS

OERYL W. GINGERY
LARRY A. MULLER
FLOYD E MONTGOMERY
JOHN ~ CASKEY
DOUGLAS C. STOVALL
WILLIAM A. STERLING

Gingery Alssociates, Ine.
CONSULTING ENGINEERS
2840 SOUTH IIALLEJO STREET
ENGLEW.OOD, COLORADO 80110
TELEPHONE [phone]

MEMORANDUM

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BRANCH OFFICE
GRAND JUNCTION.
COLORADO 81501
TELEPHONE [phone]

MEMO TO:

File

FROM:

John Blair

RE: Hydrology Adjustments Downstream of
Kelly Road Dam due to Improvements
at Kelly Road Dam

DATE:

September la, 1980

At Kelly Road Dam

The total outlet discharges at lith Avenue were given to us by the Corp of Engineers.
These will be used at this location. With the outlet works and spillway (cfs) being
conveyed by the main channel and the west bank flow flowing overland as sheet flow even-
tually making it back to the main channel. These Q's and the compairson to the old Q's
before improvements are shown below.

Outlet Works Outflow
and West Total Before
cequency Spillway Embankment Outflow Improvements Difference
10 291 0 291 385 94
50 685 0 685 1800 1115
100 1200 1569 2769 2950 181
500 1700 3800 5500 6800 1300

Referring to the hydro graphs from the Flood Hazard Delineation Report, it is noted
that the time lag between the discharge from the pond and the local flow entering
Westerly Creek is significant enough that the two peaks can be looked at separately
and the local inflow has no effect on the discharge from the pond. Because of this,
the difference between the outflow Q' s before and after improvements can be subtracted
from the outlet portion of the hydro graph at each location downstream. The outlet por-
tion of the hydrograph from the pond for improved conditions and old conditions is
assumed to be routed approximately the same.

At Colfax

The outlet Q from the pond remains about the same as it is routed from the pond to
Colfax. When the reduction of this peak by 200 cfs is made to take in account improved
conditions, this is enough to make the local inflow peak be larger than the pond out-
flow peak, where as before, improvements the outflow peak was larger. The Q peak =
2850 cfs (reduced from 3000 cfs).

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