Dam Control

[Peck]

Can anyone tell me who is in control of the Dam in Lake Port? And why is it closed with the lake so over full?
I don't understand why they keep it high in the spring so alot of boaters can not get on the lake and they drop it so early in September and drive boaters of the lake when there is another good month of boating.

[NoBozo]

Originally Posted by Peck

Can anyone tell me who is in control of the Dam in Lake Port? And why is it closed with the lake so over full?
I don't understand why they keep it high in the spring so alot of boaters can not get on the lake and they drop it so early in September and drive boaters of the lake when there is another good month of boating.

It's the "SeaKester" ..NB

[tis]

They worry about the people downstream from us.

[Rusty]

It's a long story, but here it is:


Lakeport Dam at Lakeport


Water Level and Flow Constraints:
June 1 through Columbus Day (Summer Recreation Season)
To the extent that weather conditions allow, levels are managed between 504.32 and 502.80 to
facilitate the use of the lake for recreational enjoyment. Depending upon events and forecasts
lake levels are allowed to climb to 504.80 (about 6 inches above full) for short periods of
time to allow discharges at Lakeport to be managed to alleviate or lessen downstream
flooding/flood peaks and to avoid exceeding the capacity of downstream hydropower plants.
Currently, a considerable amount of judgment is applied when making decisions regarding flow
release during these high water periods. Since the wasting of water in excess of the
hydropower capacity at Lakeport Dam (1,050 cubic feet per second (cfs)) is of concern, the
decision to do it is based upon factors such as: rate of rise (inflow), soil moisture
condition, basin vegetation status, precipitation forecast and estimated length of time to
return levels to within the normal range. When levels reach 504.50+/-, the number of
complaints regarding shoreline structure damage or usability increases. This 71-square-mile
lake has hundreds of permanent and seasonal homes with varying degrees of shoreline development
When the level rises much above the full pond level of 504.32, impacts begin to occur. There
is at least one marina that experiences problems with bridge access (low clearance) when levels
begin to climb above full.

Issues associated with the lower end of the summer recreation range relate to hull/motor
damage to boats and, like high water, to structure usability. Many abutters are accustomed to
a certain range of water levels during the recreation season. However, when the lake is at
the lower end of the range, docks and other structures may become less accessible (ex: hull
draft is larger than depth at dock). The 250 cfs minimum outflow at Lakeport Dam can
sometimes far outpace inflow during the summer recreation season and this, combined with
normal summer evaporation, will cause the lake level to typically drop 12 to 15 inches over
the course of the summer.

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.

Summary of Operation Under Normal Conditions:
Lake Winnipesaukee is filled to between elevation 504.10 and 504.32 by June 1st. From June 1st
to Columbus day, Lakeport Dam is operated as necessary, and in conjunction with other dams
along the reach depending upon prevailing conditions, to maintain a minimum discharge of 250
cfs and to keep the lake from rising to more than 6 inches over full (504.80). Natural
meteorological conditions, coupled with the minimum discharge, typically cause the lake to
gradually drop during the months of July through October. On or near Columbus Day, a two-week
shutdown of flows at Lakeport Dam is initiated to facilitate maintenance in the river reach
from the dam to the confluence of the Winnipesaukee and Pemigewasset rivers. After the
shutdown, discharges are returned to between 250 and 1,050 cfs, depending upon prevailing
runoff and water level conditions within the basin, to facilitate the generation of hydropower.
These increased flows are maintained until the lake level drops approximately 1.5 feet to
elevation 503.00. Once this level is reached, the releases are managed so as to provide for
a lake level at or slightly above this elevation on January 1st. Additionally, DES endeavors
to maintain a discharge between 500 to 750 cfs through the extremely cold months, as lower
flows during these periods promote the formation of frazzle ice, which complicates the
operation at some of the hydropower facilities. The objective is to achieve a maximum
drawdown elevation of 502.32 in late February or early March, and then begin refilling the
lake in mid to late March depending upon forecasts and the extent of the snowpack.

Summary of Operation Under Flood Conditions:
Releases from Lakeport Dam are kept to a maximum of 1,050 cfs (the maximum capacity of the
hydropower plant at Lakeport), if possible. If the lake continues to rise or if more rain is
forecast, releases at Lakeport Dam are generally increased in stages of 250 - 500 cfs per day,
and flows are adjusted at the other dams along the river to keep pace with these releases and
local inflow. Flows above 1,050 cfs are achieved by operating the hydro plant at maximum
capacity and incrementally opening the dams 3 large floodgates. After the peak of the flood
has passed, and after flows in the lower portion of the basin have had an opportunity to
recede, flows at Lakeport Dam are increased and adjusted to keep the lake level receding
until it returns to the approximate level for that time of year. Any changes to the discharge
at Lakeport Dam are made in consideration of the effects of those changes on the downstream
reach.

The Weirs channel, which is relatively narrow and may be as little as 5 to 6 feet deep in some
areas under full lake conditions, may act to back water up into Lake Winnipesaukee during high
runoff events. In addition, the measuring flume just upstream of the Lakeport Dam may inhibit
the ability to pass water downstream. However, the capacity of the flume exceeds other
constraints to flow downstream of Lakeport Dam. Therefore, the flume is not considered a
limiting factor in flood operations.

Drawdown

Although Lake Winnipesaukee is operated within a 2-foot wide operating band, there isn't a
traditional drawdown of this lake as experienced by many other smaller impoundments
throughout the state. Rather, the traditional 9 to 12 inch drop of the lake level experienced
through the summer is maintained through the Fall season. Then in January, flows are increased
at Lakeport Dam to gradually lower the lake to about elevation 502.32 - or 2 feet below full
lake. This level is usually reached in late February or early March.

http://www2.des.state.nh.us/rti_home...0at%20Lakeport

[Slickcraft]

As Rusty has noted, it is a difficult balance. A look at the multi year chart shows that mother nature is pretty unpredictable.
http://www.bizer.com/bztnews.htm#lakelevel

IMHO they do a very good job given the constraints. My suggestion is to look at the history, be prepared for the ups and downs and enjoy the lake.

[NoBozo]

Originally Posted by Rusty

It's a long story, but here it is:


Lakeport Dam at Lakeport


Water Level and Flow Constraints:
June 1 through Columbus Day (Summer Recreation Season)
To the extent that weather conditions allow, levels are managed between 504.32 and 502.80 to
facilitate the use of the lake for recreational enjoyment. Depending upon events and forecasts
lake levels are allowed to climb to 504.80 (about 6 inches above full) for short periods of
time to allow discharges at Lakeport to be managed to alleviate or lessen downstream
flooding/flood peaks and to avoid exceeding the capacity of downstream hydropower plants.
Currently, a considerable amount of judgment is applied when making decisions regarding flow
release during these high water periods. Since the wasting of water in excess of the
hydropower capacity at Lakeport Dam (1,050 cubic feet per second (cfs)) is of concern, the
decision to do it is based upon factors such as: rate of rise (inflow), soil moisture
condition, basin vegetation status, precipitation forecast and estimated length of time to
return levels to within the normal range. When levels reach 504.50+/-, the number of
complaints regarding shoreline structure damage or usability increases. This 71-square-mile
lake has hundreds of permanent and seasonal homes with varying degrees of shoreline development
When the level rises much above the full pond level of 504.32, impacts begin to occur. There
is at least one marina that experiences problems with bridge access (low clearance) when levels
begin to climb above full.

Issues associated with the lower end of the summer recreation range relate to hull/motor
damage to boats and, like high water, to structure usability. Many abutters are accustomed to
a certain range of water levels during the recreation season. However, when the lake is at
the lower end of the range, docks and other structures may become less accessible (ex: hull
draft is larger than depth at dock). The 250 cfs minimum outflow at Lakeport Dam can
sometimes far outpace inflow during the summer recreation season and this, combined with
normal summer evaporation, will cause the lake level to typically drop 12 to 15 inches over
the course of the summer.

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.

Summary of Operation Under Normal Conditions:
Lake Winnipesaukee is filled to between elevation 504.10 and 504.32 by June 1st. From June 1st
to Columbus day, Lakeport Dam is operated as necessary, and in conjunction with other dams
along the reach depending upon prevailing conditions, to maintain a minimum discharge of 250
cfs and to keep the lake from rising to more than 6 inches over full (504.80). Natural
meteorological conditions, coupled with the minimum discharge, typically cause the lake to
gradually drop during the months of July through October. On or near Columbus Day, a two-week
shutdown of flows at Lakeport Dam is initiated to facilitate maintenance in the river reach
from the dam to the confluence of the Winnipesaukee and Pemigewasset rivers. After the
shutdown, discharges are returned to between 250 and 1,050 cfs, depending upon prevailing
runoff and water level conditions within the basin, to facilitate the generation of hydropower.
These increased flows are maintained until the lake level drops approximately 1.5 feet to
elevation 503.00. Once this level is reached, the releases are managed so as to provide for
a lake level at or slightly above this elevation on January 1st. Additionally, DES endeavors
to maintain a discharge between 500 to 750 cfs through the extremely cold months, as lower
flows during these periods promote the formation of frazzle ice, which complicates the
operation at some of the hydropower facilities. The objective is to achieve a maximum
drawdown elevation of 502.32 in late February or early March, and then begin refilling the
lake in mid to late March depending upon forecasts and the extent of the snowpack.

Summary of Operation Under Flood Conditions:
Releases from Lakeport Dam are kept to a maximum of 1,050 cfs (the maximum capacity of the
hydropower plant at Lakeport), if possible. If the lake continues to rise or if more rain is
forecast, releases at Lakeport Dam are generally increased in stages of 250 - 500 cfs per day,
and flows are adjusted at the other dams along the river to keep pace with these releases and
local inflow. Flows above 1,050 cfs are achieved by operating the hydro plant at maximum
capacity and incrementally opening the dams 3 large floodgates. After the peak of the flood
has passed, and after flows in the lower portion of the basin have had an opportunity to
recede, flows at Lakeport Dam are increased and adjusted to keep the lake level receding
until it returns to the approximate level for that time of year. Any changes to the discharge
at Lakeport Dam are made in consideration of the effects of those changes on the downstream
reach.

The Weirs channel, which is relatively narrow and may be as little as 5 to 6 feet deep in some
areas under full lake conditions, may act to back water up into Lake Winnipesaukee during high
runoff events. In addition, the measuring flume just upstream of the Lakeport Dam may inhibit
the ability to pass water downstream. However, the capacity of the flume exceeds other
constraints to flow downstream of Lakeport Dam. Therefore, the flume is not considered a
limiting factor in flood operations.

Drawdown

Although Lake Winnipesaukee is operated within a 2-foot wide operating band, there isn't a
traditional drawdown of this lake as experienced by many other smaller impoundments
throughout the state. Rather, the traditional 9 to 12 inch drop of the lake level experienced
through the summer is maintained through the Fall season. Then in January, flows are increased
at Lakeport Dam to gradually lower the lake to about elevation 502.32 - or 2 feet below full
lake. This level is usually reached in late February or early March.

http://www2.des.state.nh.us/rti_home...0at%20Lakeport

Rusty: NEED More Detail... NB

[thebix]

Smith Mountain Lake in Virginia is owned and run by AEP for hydro power purposes. (It was used as Lake Winnipesaukee to film the movie 'What About Bob')
See http://www.smithmtn.com/about/SmithMountainLake.aspx
It's level is managed over a 2 foot difference, depending on power needs, while its downstream partner Leesville varies over 13 feet!
On a hot Saturday in the summer (like 95-100 most of July, it is Virginia) the level drops by a noticeable several inches, only to be refilled overnight.
Some seasons, when the area suffered droughts but AEP was required to maintain a specific flow downstream, the lake has varied during the year by 5- 8 feet!

[upthesaukee]

10 PM level today is 504.58. With full lake being 504.32, we are .26 ft over full, which is right at 3 inches. 0.083 ft equals 1 in.

A little tight at Parker's under rte 11, but we may try it tomorrow afternoon.

[Rusty]

Originally Posted by NoBozo

Rusty: NEED More Detail... NB

Har Har Hardy Har Har.
.
.
.

[BroadHopper]

Originally Posted by thebix

Smith Mountain Lake in Virginia is owned and run by AEP for hydro power purposes. (It was used as Lake Winnipesaukee to film the movie 'What About Bob')
See http://www.smithmtn.com/about/SmithMountainLake.aspx
It's level is managed over a 2 foot difference, depending on power needs, while its downstream partner Leesville varies over 13 feet!
On a hot Saturday in the summer (like 95-100 most of July, it is Virginia) the level drops by a noticeable several inches, only to be refilled overnight.
Some seasons, when the area suffered droughts but AEP was required to maintain a specific flow downstream, the lake has varied during the year by 5- 8 feet!

Lake Norman in NC varies by as much as 6 feet because of hydro power. Be thankful we don't depend on Winnipesaukee hydro!

[Pineedles]

Ok, so they use "SCIENCE" to control the flow. Next question, if there were no dam at Lakeport, what would the lake level natural range be?

[LIforrelaxin]

Originally Posted by Pineedles

Ok, so they use "SCIENCE" to control the flow. Next question, if there were no dam at Lakeport, what would the lake level natural range be?

I think what you would find is that with out the dam at lake port, there would be several areas that would not be navigable anymore..... Also there would be some underwater hazards that would not be so under water anymore...

And many of use with lakefront property would suddenly have larger beaches and would need to rebuild our docks further out.....

just how much does the dam raise the level of the lake I am not sure, but I would say that at least 5 or 6 feet would be gone easily with out the dam, and it probably is more then that....

[SIKSUKR]

That and you would need a kayak to negotiate the now long gone river between Lake Paugus and Winni.

[Tired of Waiting]

Originally Posted by Peck

Can anyone tell me who is in control of the Dam in Lake Port? And why is it closed with the lake so over full?
I don't understand why they keep it high in the spring so alot of boaters can not get on the lake and they drop it so early in September and drive boaters of the lake when there is another good month of boating.

Send some of that water over to the Ossipee's next year. This is what the water level looked like this year at the end of April and the first week of May.

I couldn't park my boat at the dock without the bow resting on the bottom. That deck is 30 ++ feet long from the shore line to the end.

ToW

[Belmont Resident]

Originally Posted by Tired of Waiting

Send some of that water over to the Ossipee's next year. This is what the water level looked like this year at the end of April and the first week of May.

I couldn't park my boat at the dock without the bow resting on the bottom. That deck is 30 ++ feet long from the shore line to the end.

ToW

Why is the lake so low?

[Tired of Waiting]

The town turned the dam control over to the "Main Power Co." who has a generator on the dam. Or so I've been told. They don't know how to control the water level yet.

Once the marina's had to stop putting customer boats in due to low water they finally closed the gates down. They closed them so far that the Ossipee river was but a trickle from normal flow.

It took about two weeks to get the level up. About a week before you could navigate the No-Wake zones with motor down.

While I was there the "channel" at spindle point, and I mean "mid Channel" only had 1-1/2 feet of water. I had to run it with my engine up to the point that the prop was almost out of the water..

ToW

[ishoot308]

Originally Posted by Tired of Waiting

The town turned the dam control over to the "Main Power Co." who has a generator on the dam. Or so I've been told. They don't know how to control the water level yet.

Once the marina's had to stop putting customer boats in due to low water they finally closed the gates down. They closed them so far that the Ossipee river was but a trickle from normal flow.

It took about two weeks to get the level up. About a week before you could navigate the No-Wake zones with motor down.

While I was there the "channel" at spindle point, and I mean "mid Channel" only had 1-1/2 feet of water. I had to run it with my engine up to the point that the prop was almost out of the water..

ToW

When was that??

[Tired of Waiting]

Originally Posted by ishoot308

When was that??

As I stated in the post "I was told" the dam control was turned over. However it was from a marina so I do put a little credibility in it. They say it was turned over a year ago.

That's all I know but will check it out some more..

ToW

[ishoot308]

Originally Posted by Tired of Waiting

As I stated in the post "I was told" the dam control was turned over. However it was from a marina so I do put a little credibility in it. They say it was turned over a year ago.

That's all I know but will check it out some more..

ToW

Sorry for the confusion, what I meant was, when was the water that low in the Spindle point channel??

Thanks;

Dan

[Tired of Waiting]

Originally Posted by ishoot308

Sorry for the confusion, what I meant was, when was the water that low in the Spindle point channel??

Thanks;

Dan

The picture I posted was taken on 4/29/2013 so It must have been a day or so before that to that day. I took the picture on our way back from the main lake where we were fishing.

The first set of channel markers in Broad Bay heading towards the main lake is where it was so low.

We have a new neighbor who bought a brand new Toon with a Merc 115 on it. I told them if they go out to be VERY careful due to the low water. I guess he wasn't because on his maiden voyage he took 1-1/2 inches off all three blades on his prop. And yes it happened at Spindle Point.

ToW

[ishoot308]

Originally Posted by Tired of Waiting

The picture I posted was taken on 4/29/2013 so It must have been a day or so before that to that day. I took the picture on our way back from the main lake where we were fishing.

The first set of channel markers in Broad Bay heading towards the main lake is where it was so low.

We have a new neighbor who bought a brand new Toon with a Merc 115 on it. I told them if they go out to be VERY careful due to the low water. I guess he wasn't because on his maiden voyage he took 1-1/2 inches off all three blades on his prop. And yes it happened at Spindle Point.

ToW

Sorry TOW, sometimes I'm a little slow ...your talking Ossipee Lake not Winni!!

When you said "Spindle Point" I immediately thought Winni and I was trying to think how the heck the water could be low at Spindle Point and not at Welch Island!! Anyway, when you mentioned Broad Bay the light came on! I also should of re-read your initial post where you mentioned the Ossipee's!

It must be time for my nap!

Thanks!

Dan

[Rusty]

Originally Posted by Tired of Waiting

The town turned the dam control over to the "Main Power Co." who has a generator on the dam. Or so I've been told. They don't know how to control the water level yet.

Once the marina's had to stop putting customer boats in due to low water they finally closed the gates down. They closed them so far that the Ossipee river was but a trickle from normal flow.

It took about two weeks to get the level up. About a week before you could navigate the No-Wake zones with motor down.

While I was there the "channel" at spindle point, and I mean "mid Channel" only had 1-1/2 feet of water. I had to run it with my engine up to the point that the prop was almost out of the water..

ToW

The State of NH acquired the Dam from Central Maine Power in 1992, and the DES operates the Dam with assistance from the Ossipee Lake Authority.
There has been a lot of controversy about the height of the water at different times of the year.

[jeffk]

The original post complains the Lakeport dam is closed but this link http://www2.des.state.nh.us/RTi_Home...E=Lakeport+Dam shows the dam output has been regularly raised since May 26 and is currently over 1400 CFS which, I believe, means the flood gates have been opened to some extent. The lake is nowhere near being flooded, just a couple inches over "full" after some heavy downpours yesterday. If they keep pouring out the water at this rate it will drop the lake about an inch a day (I believe). At that rate the lake should be down to "full" level in a 3 to 5 days. That's hardly a big deal.

[BroadHopper]

The weekend before, my slip was underwater. Last weekend it was fine. The dam operators do a good job at keeping the water under control.

The last time I saw my slip underwater was the Mother's Day flood of 2006. The slip was underwater for almost a month. I believe that was the time Silver Lake in Lochmere experience heavy flooding. It is a fine line to balance the flow between Lake Winnipesaukee and the Lakes down river.

[jeffk]

The flow is the amount of water leaving Lake Winnipesaukee at the Lakeport Dam. It is measured in cubic feet per second (CFS). To put this in perspective, 1920 CFS is enough to fill about 45 swimming pools each minute. For a period of 24 hours, 1920 CFS yields 1.24 billion gallons, or enough water to lower the level of Lake Winnipesaukee one inch. The flow fluctuates depending on the time of year and the lake's height. The long-term average is about 550 CFS.

So 1400 is not quite an inch drawdown per day. Of course there is additional run off after a big rain storm and the normal inflow sources that need to be balanced. However, at this rate it will come down in less than a week. And again, the dam is being actively managed and NOT "closed".

[Tired of Waiting]

Originally Posted by Rusty

The State of NH acquired the Dam from Central Maine Power in 1992, and the DES operates the Dam with assistance from the Ossipee Lake Authority.
There has been a lot of controversy about the height of the water at different times of the year.

I trusted the word of the marina person. I should have done more investagation before I posted about who operated/owned the dam.

I'm not local so I have to trust those who are. Me bad.

In any case the water was WAY to low for the time of year.

ToW