View Full Version : streams with higher PH
06-21-2007, 07:28 PM
Is there any truth that streams with higher ph's have not only better larger and healthier trout but a more diverse insect population,offering heavy hatches,timely and predictable, and if the insect thing is true---Why is this so?---oh yeah---are these Basic(opposed to acidic)streams cooler by a degree F or less because the composition of the flow is more a-kin its au-naturale state from years ago---a guy,I know, who fishes some,hikes a lot,was tree-ed by a bear in Glacier,and considers himself pretty well informed about conservation and stream stuff,says PH is a very fragile part of a ecosystem.He says PH of all things that fall into that ecosystem will determine wheather it stays or vanishes.If true,what is the cure?????
06-21-2007, 08:20 PM
High pH streams are normally associated with spring creeks which are primarily associated with limestone areas. The primary constituent of limestone is calcium carbonate and when combined with the nutrient rich spring water (nitrate and phosphate mostly) this will make for a very productive stream. There will be a lot of food for the trout so there will be more and bigger trout. This is assuming that there is adequate cover for the fish.
Slightly basic pH's (between 7.1 and about 8.2) are more desirable for aquatic life than acidic pH's. This will lead to greater aquatic life diversity, more food and a more stable ecosystem.
06-22-2007, 08:55 AM
Hey SoftHackle, , do you know if the calcium plays apart as well as the >7.0 pH? The reason I ask that is in the other post on this topic I proposed it would not be too difficult to set up a process to automatically adjust pH. Using limestone or any calcium based compound as the reagent to do the adjusting is not easy because it is not that water soluble so I believe gravel or quickime is used and the stream is allowed to run over the basic source and slowly leach out the calcium compound. This technique would require a large amount of gravel or powder because of the low water solubility.
In my thinking if you could use sodium hydroxide to add base, you could mix a dilute solution and pump it in at any rate you want by proportionate control based on the stream flow. The sodium hydroxide for all intents and purposes is infinitely soluble at the levels I am talking about. I would think something like a 1% solution.
I would put this question to any of the people who know water stream chemistry, something of which I am ignorant. Does the source of the base have an impact on the biology of the stream as long as the pH is controlled in the right range? Does it matter whether it is calcium based or sodium based?
06-22-2007, 10:28 AM
Isn't Calcium a primary element,mineral ,needed for growth, not only for bones but for formation and growth of muscle,or in this case the meat of the trout...Is sodium hydroxide cheaper?
06-22-2007, 11:17 AM
Lauxier, sodium hydroxide is not cheaper, it would just be easier to use in terms of adjusting pH. You could make sodium hydroxide into a solution with water at any concentration, say between (0 to 20)%. You could hold the solution in a tank. You could then precisely meter the sodium hydroxide into the stream. You could place a pH probe in the stream, say 10 to 20 feet downstream of the metering point to measure the adjusted pH. If the adjusted pH was too high you could lower the addition rate by say slowing down the speed of the injection pump or you could increase the injection rate if the pH was too low. This could be done automatically and is very easy to do.
Limestone ( CaCO3: calcium carbonate) is not very soluble in water so you have to have a lot of crushed limestone over which the stream flows. You would dump limestone into the stream or a "diversion" side stream of the stream is removed from the main body of the stream and diverted over a limestone gravel bed. These limestone beds have to be of a substantial length inorder to get the proper pH adjustment because of the low solubility of Cacium carbonate in water.
By using sodium hydroxide addition you would only need a tank of the solution and the pump along with the pH sensing devices and some valving for emergency shutoff. The sodium hydroxide method would of course require safeties because of the possibilty of having the whole contents of the tank dumped into the stream, which would be very bad.
I believe as I have talked through this , the main disadvanatge of Sodium hydroxide addition is the possibilty of tank failure, or of some equipment failure that would allow too mush base into the stream and possibly result in fish kill!
Limestone addition is essentially a passive way to adjust pH whereas sodium hydroxide would be active. But as I have said before active methods of controlling stream pH are simply an Engineering problem.
06-23-2007, 10:29 PM
Hey SoftHackle, , do you know if the calcium plays apart as well as the >7.0 pH?
Calcium is a measure of hardness while pH is a measure of hydrogen ion (H+) content. Usually hard water has a pH above 7.0. At a pH above 7.0 calcium carbonate is in a usable form for the organisms in the stream. I know that there has been some work using crushed limestone to raise the pH in streams in West Virginia that were affected by acid mine drainage and if I remeber correctly they were successful.
06-23-2007, 10:58 PM
This is actually pretty interesting stuff. I live in an area where these very processes are being utilized on AML sites along with other reclamation. The aforementioned disadvantages for Sodium Hydroxide, I have seen Calcium Hydroxide also used, are very well stated. The other huge one from my experience, is the operator. Unfortunately I have seen a situation where where a @ 2000 gallon tank of Sodium Hydroxide was set next to a diversion channel where some low ph water was being diverted through. The tank was set up to act as a crude titration system with a hose essentially attached to a valve that fed into the ditch to mix with the bad water. The rate was predetermined to be adequate to treat the water before release into a receiving stream. Problem in this case was the operator forgot to turn the valve on. Long story short, nice fish kill. Other crude processes inlude essentially the trucking in of tankers and whole dumping of calcium hydroxide into basins. Driving by sites along the interstae you can tell when a load has been dropped. One day the water is relativly normal looking, next a light bluish color.
Anyways, back to my title, I have always been curious about these types of operations and the actual benefit to the macro benthos community. I am sure there is some but the one thing I can't get pass is this. With these type of sites pH is of real concern and should be addressed, but it seems conductivity is somewhat forgotten. If I understand correctly, typical undisturebd landscapes usually carry conductivity in the range of 0-500 (sorry don't remember the unit of measure). Typically the macro benthos community is diverse for that area. However once you get into large land disturbance, agriculture/mining, where pH (from mining) can become an issue also, conductivity jumps. 500-1000/1500 maybe some limited diversity, typically more of monocultures (if that is the right word). With these mining sites, especially abandoned mine lands, much higher, (3000 +) and macro benhtos communities disappear altogether with the exception of some hearty worms maybe. So is there a process to also address the conductivity of the water as well as the pH? We can mitigate the pH, but what about the conductivity?
I would guess the natural alkaline streams also benifit from low/very low conductivity also benefiting the macros thus the trout. Just thinking out loud I guess.
06-25-2007, 09:32 AM
Hoosier, the label on the conductivity number is microsiemens. Microsiemens are the inverse of resistivity(SP.) which is micomohs, I believe. You put out the range of 0 to 500. Well in the area of SW Ohio where I am from, we get our water from wells that are over limestone deposits and the conductivity is typically about 600 microsiemens, which is high and the conductivity is due to calcium which makes it very hard. Your lower number of 0 in the natural environment is probably not attainable. Zero conductivity is the abscence of any ions in the water. I would say most natural water would be in the conductivity range of 50 to 600.
Calcium Hydroxide is not that soluble in water (.185 grams/100 grams H2O), where as sodium hydroxide (42grams/100 grams H2O Cold) is very soluble so it would be much easier to work with sodium hydroxide. You described a system for sodium hydroxide addition that is rudimentary, that depended on a unskilled operator to adjust a valve and apparently no other control mechanism. That is why I stated that the addition of sodium hydroxide is an engineering problem. A system could be designed, built and installed such that it would operate on it's own and have inherent safeties to avoid error. Of course a man would have to turn the thing on and men would have to replenish the sodium hydroxide but those tasks could be done by trained chimpanzees.
It all gets down to money. Most of these stream treatment systems are done on the cheap or are done incorporating passive means (crushed limestone beds). I am proposing active systems that will cost money but can be installed with little space and will effectively be able to handle any type of acidic water. It should be noted that 99% of acidic streams exiting industrial sites throughout the US are pH adjusted by sodium hydroxide addition, so we are putting alot of sodium ions into our rivers. My question, yet unanswered is do trout streams suffer from too many sodium ions in the water versus calcium?
I would say that adjusting conductivity down in the natural environment would best be addressed by diluting the high conductivity stream with a lower conductivity stream. A conductivity of 3000 microsiemens would represent abnormally high levels. I would say the 3000 microsiemens water must be held up in settling ponds of some sort and some type of organism, plant or bacteria cultivated that would feed off of the material giving way to high conductivity. I have to say that I do not know the limitations of conductivity on aquatic life but 3000 is very high.
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