Quote:
Originally Posted by Descant
It can be a complicated calculation. Also to be considered: how saturated is the watershed before it freezes, how much rain, how much snow, what is the snow pack in February/March, which downstream dams will be lowered for repairs, etc, etc. Regardless, there's a bit of a SWAG in there anyway.
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"Columbus Day through December 31st
To the extent that weather conditions allow, the lake level is managed between elevations
503.00 and 503.50 during this period by releasing water at a rate that can be fully utilized
by the downstream hydropower plants (250 to 1,050 cfs). This is done to facilitate shoreline
property maintenance. If deemed appropriate, and based upon basin conditions and weather
forecasts, levels will be allowed to climb above this range to prevent releases at Lakeport
from exceeding 1,050 cfs. When the level begins to encroach on the full summer elevation
(504.32), releases will be increased beyond the capacity of the hydropower plants to make
lowering the lake level the first priority. DES also endeavors to reach a target level of
approximately 502.80 on December 31st, which is approximately six inches above the full
drawdown depth of two feet. The water stored in this remaining six-inch band is release
during the coldest months of January and February.
January 1st through May 31st
To the extent that weather conditions allow, water is released from Lakeport Dam to reach the
full 2-foot drawdown (502.32) in the lake by about the end of the first week of March. The
actual depth of the drawdown varies from year to year depending upon meteorological conditions;
including prevalent base flow rates and snowpack. From March through May 31st the lake level
is allowed to climb as snowmelt, soil moisture and lake ice conditions allow. Discharges at
Lakeport Dam are made based on both actual and predicted weather events. Ideally, flows will
be maintained between 500 and 1,050 cfs throughout the period. During extremely cold periods,
flows lower than 500 cfs cause frazzle ice to form along a steeply sloped reach upstream of
Franklin center, causing maintenance problems and reduced turbine efficiency at the local
hydropower stations."
https://www4.des.state.nh.us/rti_hom...E=Lakeport+Dam