FLOOD03557

• County: Grand
• Community: Granby
• Stream Name: Tenmile Creek
• Basin: Colorado Mainstem
• Title: Granby Community File
• Date: 1/1/2001
• Prepared For: CWCB
• Prepared By: CWCB
• Floodplain - Doc Type: Community File

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Proc, No.:

W-G-l

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Date: March 1980

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is 8279.7. At this time, the gates should be lowered .1 foot if the
top of the gates is ,5 foot above the water surface elevation. Under
this condition, the gates would be lowered .1 foot for each .1 foot
drop in water surface el evation. . However, the gates should not be
ra i sed unl ess the water surface e 1 evat i on reaches 8280 or ri ses to .2
below the top of the gates. By permitting the water surface to rise,
the tendency to raise and lower the gates due to diurnal fluctuation
is lessened. After the gates are completely closed, in the absence
of il'\structions to the contrary, the discharge through the outlet
valves will be reduced gradually to maintain or regain a water surface
elevation of 8279.7. .

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Operating personnel at the Granby Pumping Plant will compute the
outflow from Lake Granby to the river. daily as measured at the Parshall
flume below Lake Granby. ToAacilitate adjustment of the release, the
water level at the gaging '~tation is teJemetered to the gate chamber.
When outflow is in excess of the capacity of the measuring device,
the total daily outflow wi 11 be estimated based on gate openings of
the valves and spillway gates. A record of changes of valve and gate
settings will be kept during these periods. During May through
September, the daily flow of the Colorado River at the gaging station
below the Coffee-McQueary Ditch \'Iill be computed from rating tables
furnished by the USGS. The gage height at this station is telemetered
into the Granby Pumping Plant. The daily quantities pumped from Lake
Granby to Shadow Mountain Reservoir will be computed based on energy
used versus pumping head. The water surface elevation of Lake Granby
is telemetered to the Granby Pumping Plant.

There is no stream gaging station on the Colorado River below Shadow
Mountain Reservoir. The release will be computed based on gate opening.
The minimum release from Shadow Mountain Reservoir normally is
25 ft3/s from October 1 through'May 31 and 50 ft3/s from June 1
through September 30. This may be reduced by the Water Scheduling
Division if the average inflow is less than these amounts. The
release may also be reduced or increased at the request of other
parties if approved by personnel of the Colorado Department of Natural
Resources, Forest Service, and the Project Manager. Normally, releases
. in excess of the mi ni mum requi rements at the request of other part ies
will be made with the understanding that the excess will be compensated
for by lower releases at a later date. The water surface elevation of
Shadow Mountain and Grand Lak.e is telemetered to the pumping plant.

The daily inflow to Willow Creek. Reservoir will be computed based
on the release to the stream, Coffee-McQueary Ditch diversions, the

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