Tully - This I Did Not Know

[Letort]

Tully is on my list to fish sometime, given that it is only about 1 hour away.

At a recent TU meeting, a speaker who guides on the Tully gave a good presentation on the watershed. I have always followed posta about the stream, given its reputation and my takeaway is that it can be quite fickle, heavily pressured but has a share of strong supporters.

What I did not realize is that within the past several years, the bottom discharge of the Blue Marsh is not working. Therefore, all the water discharged is from the top, which is the warmest water in the watershed. Since the coldest water is not being discharged, it has significantly affected the stream and therefore the trout population.

I guess I completely missed that, but is that a well known impact on the waterway?

 

[KELORGO]

I did not realize there even was a bottom discharge, as I’d only heard of the upper discharge. I’ll be following to see what I can learn from others 👍

 

[Letort]

I did not realize there even was a bottom discharge, as I’d only heard of the upper discharge. I’ll be following to see what I can learn from others 👍

The statement came from someone that guides on it and grew up fishing it. Said the Corp of Engineers is responsible for maintenance and has expressed no interest in fixing the issue. He didn’t say this, but reading between the lines, the Corp only cares about managing water runoff, not its temperature.

 

[Letort]

With the top discharge, also explains why their is more downstream sediment that from the bottom discharge.

 

[Mike]

What I did not realize is that within the past several years, the bottom discharge of the Blue Marsh is not working

Last July I was watching the daily stream temps at the gauge downstream from the dam. Temps did not suggest that there was a problem with the bottom discharge. They looked pretty typical. I suspect that the present AFM will be checking into this.

 

[Letort]

The speaker said the bottom discharge has been out of order for several years. So depending on what you are comparing, if YoY, it would not show up.

 

[LehighRegular]

The speaker said the bottom discharge has been out of order for several years. So depending on what you are comparing, if YoY, it would not show up.

Whom ever was the speaker they are flat out wrong.

 

[Clarmy]

No expert but I was always told it's a top water release. Water seems too warm for bottom release. I'd be interested to know the correct verdict.

 

[Solitariolupo]

I was always told water from bottom is colder in summer warmer in winter.

 

[Mike]

No expert but I was always told it's a top water release. Water seems too warm for bottom release. I'd be interested to know the correct verdict. water intentionally

Semi-top water (not right at surface but perhaps 10-15 ft down), but essentially top water. It’s mixed with bottom water more and more starting when the trigger for mixing is hit, which is the first three mornings in a row at 8 AM when the water temp in the tail-race gauge is 68 deg or warmer. It’s mixed in only enough to keep hitting 68 deg F tailrace temp at 8 AM, thus the stream is never “cold” just because mixing has been initiated, but this technique conserves the cold water for use in mixing for the greatest time through the summer.

The cold water supply is typically exhausted between July 22 and Aug 2, but can disappear sooner if storms result in the necessity to temporarily open gates farther at times through the summer. On the other hand, a wet summer may cool the lake a bit, which with ideal timing has apparently produced more trout surviving the summer on rare occasions. Timing apparently has to be perfect though.

Note: 68 F is the starting temp for temperature stress in RT and BT. This is one practical reason why I would have preferred a June 1 start to the harvest period. Mixing usually starts sometime in the first two weeks of June before the harvest period even begins.

 

[poopdeck]

A broken gate with indifference to repairing sounds like bad poop to me but maybe I’m naive. I just can’t see the Corp of engineers overlooking broken/neglected flood control gates on a flood control dam with a rating of “high” for potential of catastrophic property damage and loss of life in the event of a dam failure.

I’m sure, but really do not know one way or the other, that if a mega huge component of a dam like a controlled gate was broken, immediate repair is mandated with no discussion or indifference.