Tully Water Temp

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Noticed the water temp on the Tully jumped up suddenly about 4 degrees a couple of days ago. Any thoughts?

Tully Temp
 
We are having a heat wave; fish somewhere cooler if possible....
 
Blue Marsh is a little different than most places due to the dam.

Essentially, they'll pull water from the top until it gets too warm for trout. Once it surpasses a certain temp, then they start adding colder, bottom water, to bring it back to around 70 F or so, increasing the amount of bottom water as needed to keep it from going up any higher, but not making it any cooler (which would be a waste of the limited cold water).

It will pretty much then hold at that temperature until they run out of cold water at depth in the lake. From there, they can't really control it and it gets too warm, rather suddenly. I'm sure someone could give you the exact temperatures and rules and so forth.

Might as well fish it if you want. They're stockies. Very few will survive the summer anyway. They'll put more in next fall to replace them.
 
Don't forget the "fish keepers" will soon be taking them also. It's that time that I turn my interests north.
 
I just came back from taking the water temp with my trusty meter. Lake surface water temp was 70º. The Stilling basin was 65º and the temp at the Gauging Station was 64º. They may be having a problem with the equipment which has happened in the past. Especially since the temp jumped 4º in one day.
Also, when the PFBC did electrofishing at Station 5 which is below Reber's Bridge, they would get anywhere from 100 to 200 fish in a 1200 foot stretch. Usually one quarter of the trout were holdovers. There is a significant number of holdover trout in the DHALO section. If you did not harvest the trout I am sure there would be more.

FCP
 
FCP likely knows more about the Tully than anyone and certainly has an amazing historical database to back it up.

Could this USGS data be off due to the satellite switch over? I know a lot of gauges were off line or incorrectly reporting due to the switch over.
 
Likely switched to top release, as Pcray posted.


 

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i.e. it has become time to conserve the cold water, and use as little of the bottom water as needed.

That's the one thing the Tully has going for it. That dam allows both top and bottom release, and precise ability to control the mix.
 
This subject (Tully temps) comes up every year. Here is a thread form the past with a lot of info on the subject:

Tully temps
 
If FCP is right, and fish hold over (I don't doubt that), and more would hold over if people stopped harvesting them, I wonder if the Tully couldn't benefit from a no-fishing season from say, July 1 through the end of August. I'm sure plenty of fish die too from dudes who go, fish 72 degree water, and practice "good C&R".

PS-I can think of a few other streams that could benefit from a closed season as well. Lititz Run and Kettle Creek, just off the top of my head.
 
When the cool water pool is exhausted, the Tully really gets warm. and Cacoosing and Plum (the tribs in the DH sections) offer little in the way of a cool water respite for the fish.

Nowadays the stream seems to get really [d]warm[/d] hot (see below). I can't access the data from back in "the day," but i seemed like there was more cool water and the fingerlings seem to make it through the summer in better shape and in greater numbers. Perhaps the cold water pool was larger back then?...don't really know.

I have witnessed fish being lethargic and gasping for air well before the hottest time of year. I really gave up fishing there as soon as the weather turns warm for that reason.


 

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Silt from the upper Tully filling in Blue Marsh, perhaps?
 
I think Blue Marsh is slowly filling with silt and getting shallower. Don't recall where I saw it but the deepest area near the dam ain't all that deep. There really isn't much of a cold water supply behind the dam compared to say the Yough.
 
Here's a full summertime view of Afish's graph. You can clearly see what they're doing.

In the spring, they've been using up topwater to save the colder, deep water, so temps increase like any other stream. About this time of the year, it was getting too warm, and they added some cold water to the mix to bring it back down. Then from that baseline it started to get too high again, and they again increased the % of the bottom water in the outflow to bring it down. This happened two more times.

Until...., there ain't no cold water left, and they can't hold the temps down anymore.

That relatively flat spot through June and July are unique, and that's the value of the bottom release They keep it JUST cool enough for trout survival for a long time period. Keep in mind, temps downstream from there will be warmer, not cooler. This is right at the dam.

Yes, the deep part of the lake was small to begin with, and is filling in with silt, so getting smaller as time goes on. That late summer mountain in the chart progressively starts a little earlier, and goes higher.
 

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Pcray. You are largely spot on with this. It is splitting hairs, but your last paragraph, and the topic therein, is something I have been watching fairly closely for over thirty years. I usually tell people that BM runs out of cold water between July 22 andJuly 28. If I recall correctly, it was around Aug 2 or so last year, which surprised me. This has been pretty consistent over the years except when a major storm forced BM to dump a lot of water earlier in the summer. In contrast, the cold water has lasted longer when we have had enough summer rain during June or early July to nearly completely replace the lake' s volume of water with " new" water. I have not noticed that max summer temps have been getting higher over time, but they may be as you say. I have not paid as much attention to that. Years ago the summer max would be about 76 degrees, but it may be higher now. By the way, water temps are taken by the gage sta. near the water authority. You are correct that water temps are probably warmer downstream and always have been except near the confluences of Plum and Cacoosing Cks. Worse now, however, is that the stream is wider and therefore shallower under the same flows when compared to years ago. As a result, fish habitat is worse too and fish are more vulnerable to avian predators. Time marches on.

Finally, to ad to what you said above, the bottom releases are started when the 8 am water temp hits 68 degrees three mornings in a row. I set this up with the Army Corps Of Engineers Back in about 1982 or 1983 after we experimented with various tail race water temp trigger values and release schedules for a few summers. It was frustrating to see how warm we had to let the stream get to extend the cool water temps through only part of the summer and we would still run out of cold water in the reservoir.
 
ACe will not let the lake go below levels suitable for boating. That should tell you everything you need to know. ACE took a cold water stream and made it a warm water stream, just as they did the Lehigh River. And what's worse the Lehigh was a brook trout stream.
 
Not so. The Tully where the lake now sits was a smallmouth bass, redbreast sunfish, rock bass , white sucker, American eel, and carp creek.

Furthermore, reducing the Lake water level through the summer would have no positive impact on downstream temps. As the lake's fisheries manager I would never recommend it from a lake fishery standpoint unless it was done to develop a vegetated shoreline that could be flooded the following spring to enhance reproductive success and juv habitat for certain lake species.
 
Mike wrote:
Not so. The Tully where the lake now sits was a smallmouth bass, redbreast sunfish, rock bass , white sucker, American eel, and carp creek.

Furthermore, reducing the Lake water level through the summer would have no positive impact on downstream temps. As the lake's fisheries manager I would never recommend it from a lake fishery standpoint unless it was done to develop a vegetated shoreline that could be flooded the following spring to enhance reproductive success and juv habitat for certain lake species.

Mike is absolutely correct. The Tully (at the point of the dam and down-stream) was a warm water species stream until Blue Marsh dam was built.
 
Mike,
Does noximixon have a lot of coldwater in it ??
If so why can't that be made into a tailwater srtream. instead of a kayak stream ??
To me given the depth of the lake around the dam and the cooler feeder streams I would think it would be a excellent trout stream. Bio mass has been incredible at times till they flood and scour it out.
 
Pretty sure there is no bottom release on nockamixon, doesnt all the water flow out of the top of the dam?
 
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