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Jon Boy
USA
145 Posts |
 Posted - 07/26/2010 : 11:25:21 PM
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The Charlotte news tonight reported that there have been "dozens" of fish discovered floating on Lake Norman today. The report went on to say an estimated 600 fish may have been killed by hot water temps/lack of oxygen. The news report stated that Duke Energy's McGuire Nuclear Plant draws water from a deeper intake during very hot water conditions. They didn't mention operation of the Cowan's Ford Dam, which is the dam impounding Lake Norman. They said the last reported fish kill was 2004 on Norman. I'll try to find out more if I can and post it.
Jon Boy |
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landlocked
USA
116 Posts |
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WILDMAN
64 Posts |
Posted - 07/27/2010 : 4:54:27 PM
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| Is their any monitoring of O2 levels in this lake? |
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Rick
USA
466 Posts |
Posted - 07/27/2010 : 9:17:49 PM
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My response, which I had a great deal of difficulty getting posted was
As the water warms, the striped bass go deeper to find the cooler, oxygenated water. When the power company also goes deeper to get cooler water, it draws the oxygenated water out of the lake, and fish die. It has happened on just about every hydro-electric operated lake in the south-east! It is a trade-off between economical operation for the power companies, and insuring the life-blood of the fishery. Many power companies, e.g. South Carolina Electric & Gas have changed their operating strategies to prevent fish kills. Sadly, some have not. This does not require a scientific study to determine how to prevent it. It just means the power companies need different operating strategies, which may cost more. But, if they are responsible for fish kills, they ought to be responsible for comparable re-stocking. Just my opinion, Rick
I could not get it to post because my original choice of words, in place of "draws" was "sucked", so they would not accept my post 
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Rick
Lake Murray, SC
Rick
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Jon Boy
USA
145 Posts |
Posted - 07/28/2010 : 09:55:35 AM
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| Well Rick, in this case, drawing off the deeper oxygenated water does suck! |
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Jon Boy
USA
145 Posts |
Posted - 07/28/2010 : 10:09:56 AM
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quote:
Originally posted by WILDMAN
Is their any monitoring of O2 levels in this lake?
I have not been able to find any monitoring for Lake Norman, or any other large NC reservoirs... Here's the link for the streams, rivers, etc.
http://www.thetent.com/thetent/aogcr/nc/ncsf_index.htm |
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Tom Gitto
222 Posts |
Posted - 07/28/2010 : 10:16:10 AM
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Our big kill in 05 was because of the pull of water from the large #5 tower the first week of August. SCE&G also pulled water this past week. Lets keep uur fingers crossed it has no effect on Murray.
Tom Gitto |
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Jon Boy
USA
145 Posts |
Posted - 07/28/2010 : 10:16:11 AM
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quote:
Originally posted by Rick
My response, which I had a great deal of difficulty getting posted was
As the water warms, the striped bass go deeper to find the cooler, oxygenated water. When the power company also goes deeper to get cooler water, it draws the oxygenated water out of the lake, and fish die. It has happened on just about every hydro-electric operated lake in the south-east! It is a trade-off between economical operation for the power companies, and insuring the life-blood of the fishery. Many power companies, e.g. South Carolina Electric & Gas have changed their operating strategies to prevent fish kills. Sadly, some have not. This does not require a scientific study to determine how to prevent it. It just means the power companies need different operating strategies, which may cost more. But, if they are responsible for fish kills, they ought to be responsible for comparable re-stocking. Just my opinion, Rick
I could not get it to post because my original choice of words, in place of "draws" was "sucked", so they would not accept my post
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Rick
Lake Murray, SC
Rick
Rick, I don't know much about Cowen's Ford dam, and what level the intakes are for the generators in that dam. It doesn't have intake towers like the Murray dam does. I do know that McGuire Nuclear has at least two intakes, one shallow and one deep. Don't know the depths of either one, but I am still trying to find out.
I would have thought the Lake Norman club would be all over this, but there's only a couple of posts on their message board about dead fish floating so far.
I'll try to find out some more info. I have a couple of contacts in the Duke Environmental group that might help me.
Jon Boy |
Edited by - Jon Boy on 07/28/2010 10:18:44 AM |
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Jon Boy
USA
145 Posts |
Posted - 07/28/2010 : 2:11:49 PM
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O.K... I found out a little bit more about the Lake Norman situation. The dam area and the forebay out from the dam are the deepest, coolest waters, and the majority of the fish locate there during the hot weather months, just like Murray. There are springs, creeks, and deep holes that are exceptions, but the majority locate there.
During normal operations, McGuire Nuclear Station's intake is at or near the surface level, and upstream of the dam. However, during extreme hot weather, they swap over to an intake that is at the dam, which is in deeper water (still don't know what depth exactly). The reasons for this are: the State of NC EPA requires Duke to meet a maximum discharge temperature. If Duke doesn't draw intake cooling water from a deeper level, they can't meet the discharge temperature regulations when the water gets really hot (unless they shut the plant down or reduce the operating power level significantly). They are reluctant to do this because that is the period of highest electricity demand on the system. The jeopardy that Duke is in is that if they run the low level intake too early in the year, they can deplete the cooler water completely, then can't meet the discharge temperature regulation in the September time-frame. The guy I spoke to said that they are having to run the low level intake earlier this year than most because the lake has heated up faster/earlier this year.
I guess it is a very similar situation to our Lake Murray/SCEG situation. The electricity demand is the highest during the hottest lake water conditions. An complicating factor for Lake Norman is that Marshall Steam Station also uses the lake for cooling water, although that is far upstream from the dam. Makes a great place to fish in February though when the water temps are really cold. I have no idea how the equation varies when the nuclear plant is drawing water in from deep water and the dam is running. It is probably much more complicated than the Murray situation. Plus, I don't know what the water quality/bacteria from discharges upstream do in Lake Norman. I recall the Lake Murray study saying that was our most serious issue, even though the tower 5 operation was part of the problem also.
Seems to me the EPA could be lobbied to relax the discharge temperature regulation during those months if they realized what an impact it can have on the striped bass. The discharge is upstream from the dam on a large fork, so not many stripers would be affected by the discharge of a little warmer water up there I would think. I have no idea how other fish might be affected, maybe that is not an option for some other reasons. Anyhow, I don't guess it is our fight to wage. We have enough to do with our SC situations, where there are no easy answers either.
All of this information is "unofficial" and some of it is from my own recollection of how the station operates (and my recollection is poor in many cases). I just thought our club would be interested in following the perils of another lake. Murray and Clarks Hill are certainly not the only southern lakes that have these conditions and fish kills as a result, as Rick stated above.
Jon Boy |
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Fish Kill on Lake Norman, NC
