Are Winnie Water Levels Higher than Normal?

[TiltonBB]

Originally Posted by mishman

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.

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.

[ishoot308]

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

[jeffk]

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.

[LIforrelaxin]

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

[LIforrelaxin]

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

[Loub52]

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

[jeffk]

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.

[LIforrelaxin]

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...

[jeffk]

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.