Are Winnie Water Levels Higher than Normal?
 

I just noticed that the water is nearly up to the bottom of my dock. Then I checked and levels are at 504.07 today (12/28/22). Don’t they usually have the lake levels much lower this close to the freeze?

https://www4.des.state.nh.us/rti_data/WEIN3_TABLE.HTML

Lots of rain in the last month
 

There was a lot of rain in the last few weeks. This has raised the lake level by almost a full foot. The stream behind my house was higher last weekend than it's been in probably 5 or 6 years. It was almost overflowing the banks. It's now back to being just a stream.

I would guess the level will start to drop again soon.

Dave

Take a look at the Bizer chart:

http://www.bizer.com/bztnews.htm#lakelevel

oh, and the "they" that control lake level is actually a "she" AKA Mother Nature

Alan

Lakeport could spill more.
But I think that is only done should the level be exceptionally high.

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.

Water Level
 

The water level is exactly where it should be for this time of year.

Dan

"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

It just hasn't reached the 504.32 to open the spillway.

Why there's not a bigger release to lower lake?
 

According to this chart https://www.des.nh.gov/sites/g/files...-graph2023.pdf
the lake is 3/4 of a foot above normal for this time of the year. What I don't understand is why there is not a greater release to bring the level down to average for this time of the year. If the lake freezes at this level, it will do damage to shore structures like cantilevered docks.

Are Winnie Water Levels Higher than Normal?
 

Could be the level is just as high downstream. The Merrimack River appears high going through Manchester


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The lake level on Winnipesaukee is not maintained without consideration for the other lakes downstream. The outflow goes through Opechee and Winnisquam and eventually to the Merrimack River and out to the ocean. There are times when they are maximizing the flow based on what the downstream lakes and rivers can handle.

With this year's weather they may be less worried about ice damage in the near future and more interested in maintaining a slower flow for hydropower purposes.

Lake Level
 

With the recent rain, the lake water level is now above the average for this time of year though still below the "full pool" level. I'm sure the dam operators will be adjusting the outflow accordingly as they have done so well for many many years...

Dan

The dam operators started upping the flow around December 21st and have continually increased it, to 1500 CFS as of today. Water levels are still a foot over typical for this time of year. I would expect that the high dam rate will continue for over a couple weeks, full outflow (1900 CFS?)) can drop the lake an inch a day. So over 16 days to drop the lake a foot at the 1500 CFS rate. Of course that doesn't account for and significant rain we may get in that time.

I looked this morning the flow is at ~1650 cfs.... give it a few days the lake will go down....

I looked this morning and the lake is re-acting to the increased flow....

Definitely an unscientific observation. Waukewan’s outflow to Winni at Mills Falls has decreased this week.

Since Jan 5 when the dam was opened to ~1500 CFS the lake level has dropped about 2 inches. New water from rain or runoff can counter the dam release. It's a slow process to get the level down.

So we are currently at 503.95 and before the lake started to re-act to all the efforts to bring the level down it got up to 504.18 as JeffK indicated around 1/5/2023.....

now 1/10 of a foot is 1.2 inches and the delta is .23.... so the lake is down roughly 2.75 inches....

Now generally the lake is down around 503 ft. at this point..... so there is still .95 feet to be drawn down... if they can keep the rate of drop it will be back around its statistical norm in about 3-4 weeks.... hopefully weather will cooperate and that time line will move up..... and they will not have to increase flows into the lake form any of the surround lakes or ponds that feed into Winnipesaukee...

Checking today, the lake levels went down slightly and then back up slightly over the last 4 days. It's still about a foot over typical levels for this time of year. There is a note in the Operations Updates on the New Hampshire Department of Environmental Services Winnipesaukee lake level page that the dam outflow will be increased to 1920 CFS, its maximum but the Lakeport dam page does NOT reflect that change yet. At 1920 CFS, the lake drops about an inch per day, barring no significant additional rain. That means it will take about 12 days to get the lake down a foot to the typical fall/winter levels. They MUST be able to do that before the spring snowmelt runoff and "April showers" because they cannot dump all that water downstream (downstream is dealing with their own local runoff) in the spring. Instead, they let the runoff fill the lake back up and minimize the impact downstream.

My dock is nearly underwater. It is not where it should be.


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You do realize you quoted me from almost three weeks ago right???...In a subsequent post about a week later I stated... "With the recent rain, the lake water level is now above the average for this time of year".

If your dock is almost underwater now, you have serious issues as the current lake level is still below "full pool". What do you do during the months of June and July when the lake is at full pool?? :confused::confused:

Dan

Checking this morning, the lake is almost back to its "typical" Fall level of 503.1'. It is at 503.2', just over an inch "too high". Another couple days and that will be gone. It took about a month to drain off the excess foot of water. We are expected to get a little rain over the next 10 days but that should be manageable with little effort. They haven't dialed back the dam output yet, still about 1600 CFS but that will probably drop later this week.

The lake is now down to its "typical" Fall/Winter level. The dam output has been reduced to 1300 CFS and will probably be reduced further. We are expecting continued warm temps (melt water) and 1/4 inch of rain in a couple days so they may wait a bit before reducing dam output to the low levels typical of winter.