Does anyone know if it’s viable to raise a trout streams PH?

[AVL]

I’m doing some research for an article on ways to potentially improve NC trout fisheries, and one of our bigger issues is the granite substrate that i heard causes the PH to be more acidic, resulting in limited aquatic insect life, as well as overall trout health. I know they’ve mitigated PH in some higher elevation brook trout streams, but those are much smaller streams than the ones further down the hill, so to speak. I’ve muddled thru some articles, and will do more, but wanted to see what folks here say, and have seen, and that can point me in the direction of research?

NCWRC has done a pretty **** poor job with our trout fisheries, though it has a 1.4 billion dollar annual economic impact on western NC (their figures). Now they’re going to reduce stocking by 67-80% while they rebuild the primary hatchery, that’ll take a 3-5 years. Other than a few fisheries (not including the Brooke streams), trout fishing here is unfortunately pretty dependent on stocking, especially DH streams. Will take me awhile to gather up the info needed to write the article, the PH is only one facet of improvement, but it’s a big one, on the small likelihood PH can be effectively mitigated, somewhat economically.

Thanks

 

[salmonoid]

Any stream that is mitigated for acid mine drainage is addressing a low pH issue. So look at how any of the agencies that are treating AMD do it and that would be a start. A stream I fish from time to time is somewhat acidic, due to the poor buffering capability of the sandstone that is present as bedrock and the solution to help that is dumping a few tons of lime in the stream.

If there are point sources of low pH, those are generally addressed first, and that will impact the pH further downstream. But if the overall geology is bad, maybe trout aren't supposed to be there, and we humans just have to accept that, instead of trying to "fix" things.

 

[HoboWithAFlyRod]

I think diversion wells like what they have on Rausch creek above Stony creek raise the pH. It’s what makes Stony fishable, and that’s a lot bigger than Rausch. There’s some info about it on the local TU chapter’s website.

Rausch Creek Diversion Wells - Doc Fritchey Trout Unlimited

About the Wells Doc Fritchey TU has built two limestone diversion wells — the first in 1987 and another in 2000 — on Rausch Creek, a tributary of Stony Creek […]

dftu.org

 

[troutbert]

I’m doing some research for an article on ways to potentially improve NC trout fisheries, and one of our bigger issues is the granite substrate that i heard causes the PH to be more acidic, resulting in limited aquatic insect life, as well as overall trout health. I know they’ve mitigated PH in some higher elevation brook trout streams, but those are much smaller streams than the ones further down the hill, so to speak. I’ve muddled thru some articles, and will do more, but wanted to see what folks here say, and have seen, and that can point me in the direction of research?

NCWRC has done a pretty **** poor job with our trout fisheries, though it has a 1.4 billion dollar annual economic impact on western NC (their figures). Now they’re going to reduce stocking by 67-80% while they rebuild the primary hatchery, that’ll take a 3-5 years. Other than a few fisheries (not including the Brooke streams), trout fishing here is unfortunately pretty dependent on stocking, especially DH streams. Will take me awhile to gather up the info needed to write the article, the PH is only one facet of improvement, but it’s a big one, on the small likelihood PH can be effectively mitigated, somewhat economically.

Thanks

Which streams/locations are you discussing?

What are their pHs? What fish are found there presently?

 

[AVL]

Which streams/locations are you discussing?

What are their pHs? What fish are found there presently?

Streams like West Fork of the Pigeon, Big Laurel, Curtis Creek, parts of the Catawba, maybe the upper Davidson, upper Nanty. Those are all DH, or have parts that are, and have naturally reproducing bows and browns, but tend to stay small because of limited food sources. I don’t know the PH’s, and I’m in the early stages, I’m sure i don’t know what i don’t know at this point. What i do know is NC trout fisheries need a facelift, NCWRC has done little to nothing since coming up with DH back in the early 90’s. The model, at least at this stage in my research, is PA, they seem to be light years ahead of NC - they’ve been proactive, where NC has been reactive, at best. I’m old enough to know i don’t know squat about much, but i can learn, albeit at a slow rate.

 

[Paul6.5]

In 1986 I spent the better part of the summer working with Cornell University who was studying techniques to restore streams that ran through farm land.
I worked on a stream in Susquehanna County PA that had a low pH. they brought truckloads of limestone sand and limestone in various sizes to be put into the stream

As a 16 year old volunteer I spent days moving all that limestone in buckets and wheelbarrows. I don't know or recall what the results were but a lot of smart people back then thought it would help.

 

[troutbert]

Streams like West Fork of the Pigeon, Big Laurel, Curtis Creek, parts of the Catawba, maybe the upper Davidson, upper Nanty. Those are all DH, or have parts that are, and have naturally reproducing bows and browns, but tend to stay small because of limited food sources. I don’t know the PH’s, and I’m in the early stages, I’m sure i don’t know what i don’t know at this point. What i do know is NC trout fisheries need a facelift, NCWRC has done little to nothing since coming up with DH back in the early 90’s. The model, at least at this stage in my research, is PA, they seem to be light years ahead of NC - they’ve been proactive, where NC has been reactive, at best. I’m old enough to know i don’t know squat about much, but i can learn, albeit at a slow rate.

Streams that have wild browns and rainbows are not low pH streams. If the trout run small it is probably because of physical habitat limitations.

And maybe because of harvest. What are the harvest rules are on those streams? And are they stocked or unstocked?

 

[Cebe]

I believe that West Virginia has done liming of streams. One that I saw involved a refillable tank that was filled with limestone sand. I don't know the mechanism for metering it.

 

[mossyoakpenn]

As salmonoid has said, streams that are acid mine reclaimed are ph managed. To what extent, I dint know. I cant imagine it hurts to dump a couple tons of limestone in to better the ph.

 

[AVL]

Streams that have wild browns and rainbows are not low pH streams. If the trout run small it is probably because of physical habitat limitations.

And maybe because of harvest. What are the harvest rules are on those streams? And are they stocked or unstocked?

I don’t think this is completely accurate, i was told by a biologist that trout can survive in moderately low PH streams, and can reproduce, but the PH inhibits abundant aquatic insect life, thus they stay small. I’ll get a ph meter and begin checking and logging ph of streams in the area, should be pretty interesting, especially how well know, productive rivers like the Davidson compares to others.

 

[FarmerDave]

I don’t think this is completely accurate, i was told by a biologist that trout can survive in moderately low PH streams, and can reproduce, but the PH inhibits abundant aquatic insect life, thus they stay small. I’ll get a ph meter and begin checking and logging ph of streams in the area, should be pretty interesting, especially how well know, productive rivers like the Davidson compares to others.

Since Troutbert specifically mentioned Rainbows and Browns, It was accurate. Rainbow trout are the least tolerant to low (and high) ph. In fact, they cannot reproduce in pH lower than about 6, and cannot survive below 5.5. The average pH of rain in PA is about 5.6. Your statement was more general ( non-specific trout) so it also contained accurate information. Brook trout are the least sensitive to pH. They prefer pH of 5.0 to 7.5, but can indeed survive pH as low as 4 and possibly below, and successfully reproduce at about 4.5. But brook trout were not included in Troutbert's response.

 

[jifigz]

Since Troutbert specifically mentioned Ranbows and Browns, It was accurate. Rainbow trout are the least tolerant to low (and high) ph. In fact, they cannot reproduce in pH lower than about 6, and cannot survive below 5.5. The average pH of rain in PA is about 5.6. Brook trout are the least sensitive to pH. They Prefer pH of5.0 to 7.5, but can indeed survive pH as low as 4, and successfully reproduce at about 4.5. But brook trout were not included in Troutbert's response.

The OP is discussing streams in North Carolina, which I am sure everyone here is aware of.

I am not agreeing or disagreeing with anyone, but this is just an observation. If rainbows are the least tolerant of low pH, and many streams in the smokies are riddled with wild bows throughout, how low can the pH on many of these streams be? If bows can't tolerate pH and wild bows abound, it doesn't sound like there should be problems with low pH, right?

And, one more thing to note, if the said streams have a low pH, then we should strive to have a brookie fishery there anyways, since they are the natives AND more suited to the environment, especially if a low pH is prohibiting them from being colonized by bows...

 

[tomgamber]

The answer is yes. Placing limestone in the headwaters of streams is a common treatment on Laurel mtn currently. I believe I read with success.

 

[troutbert]

As salmonoid has said, streams that are acid mine reclaimed are ph managed. To what extent, I dint know. I cant imagine it hurts to dump a couple tons of limestone in to better the ph.

Liming can hurt native brook trout populations, by increasing competition from browns and rainbows.

Also, liming can raise the pH enough that hatchery trout can survive, opening up streams to stocking that were not stocked previously because the pH was too low for the hatchery trout to survive. Changing a brookie stream from unstocked to stocked devastates the brookie population. I know of examples of this in PA.

 

[Mike]

Just passively placing limestone is not enough in Pa mining situations. It either needs to continue to dissolve, perhaps the reason for limestone sand, or it needs to be refreshed/renewed. My understanding is that Limestone gravel eventually develops a thin layer of precipitate that isolates the mineral from the forces of dissolution.

“Naturally” acidic situations are probably a different story unless biofilm formation is problematic, but that’s not something that I have ever read.

 

[RLeep2]

Is the issue really low Ph/alkalinity that needs to be improved or is it more our tendencies to want to adjust/change or "fix" what is already in place as a result of the natural order of things? It's a worthwhile question, IMO.. The southern Appalachians and western NC in particular are a wild trout mecca if we keep NC sized expectations and not insist on having Montana or even Michigan sized expectations.

A good many years ago, I lived part time in NC on work assignment. I was younger then and probably logged well over 1,000 hours chasing NC wild trout. I loved it and wouldn't have changed a thing about it for anything.

But that is just me...

Anyway, one low-alkalinity mitigation project that has at least regional applicability would perhaps be the (quite successful) work done on the St. Mary's River in the George Washington NF in Virginia.

You could start here: https://www.fs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb5302400.pdf or simply do a search on "St. Mary's River liming project".

 

[AVL]

Lots of good info here, and good discussion, thank all of you. My understanding of trout biology is rudimentary at best, and I’m going off what others have told me. My daughter got her masters in biology from App State, studying hellbenders, maybe I should use my brain and talk to her about this 🤪

 

[FarmerDave]

The OP is discussing streams in North Carolina, which I am sure everyone here is aware of.

I am not agreeing or disagreeing with anyone, but this is just an observation. If rainbows are the least tolerant of low pH, and many streams in the smokies are riddled with wild bows throughout, how low can the pH on many of these streams be? If bows can't tolerate pH and wild bows abound, it doesn't sound like there should be problems with low pH, right?

Right. And that is what TB said, and I agreed to in the post where you quoted me.

Initially I thought NC in the OP meant North Central PA, but it doesn't really matter. And obviously we agree on this.

 

[FarmerDave]

There are many ways to increase pH in a watershed, both passive and active. Do a little searching on the internet.

Even creating wetlands in the headwaters, if done correctly, can raise pH. Unfortunately, it can also raise water temperatures if done incorrectly.

The work done on South Sandy in Venango County is the first one to come to my mind, because it was part of my old stomping grounds and I am old.

For what it is worth, I fished South Sandy Decades ago in a place where the pH was very low. I was on a scouting trip before internet and smart phones. There was a huge hatch of caddis and the water was boiling, so go figure. I caught lots of chubs, but no trout. I believe that was before the project got going, I often think about revisiting that spot to see if there has been much improvement.

 

[Kms]

I’m doing some research for an article on ways to potentially improve NC trout fisheries, and one of our bigger issues is the granite substrate that i heard causes the PH to be more acidic, resulting in limited aquatic insect life, as well as overall trout health.

This is not my area of expertise, but isn’t describing granite as “acidic” a misnomer? My limited understanding is that granite is nearly insoluble, so has it been confirmed that the granite is actually causing the PH to decrease, or is it that the granite merely does nothing to buffer the PH by neutralizing acidic compounds, as would limestone or some other calcium or magnesium carbonate?