acid rain/deposition and 3 PA streams

[k-bob]

https://pdfs.semanticscholar.org/61a4/901ab768a9aa1b82ae9b6806908dd21560c5.pdf

interesting how this author looks at bedrock and stream pH: he notes both the amount and the _locations_ of various bedrocks in a stream's drainage area. see for ex original page 18 ... for each stream, what are the % of drainage and locations that are catskill, burgoon, etc., bedrock formations.

these noted locations can include ridges, uplands, or streambed ... streambed locations, particularly over some distance (eg 1.5 mi or so), make a bedrock more important in shaping water pH, I assume.

for ex, young womans creek's drainage is 37% low buffering burgoon, but this is in ridges and uplands, not the streambed.

we can look up the bedrocks:

https://www.arcgis.com/home/webmap/viewer.html?layers=dba8455c266b4b958b403959185ed97b

he also notes original page 17 that influences within the bedrock formation areas shown on maps may matter... describing Young Womans Creek:

"The watershed is predominantly underlain by the Huntley Mountain formation, Burgoon sandstone, and Catskill formation (Table 2-1), giving rise to stream water with relatively high ANC (Mast & Turk, 1999; Pennsylvania Bureau of Topographic and Geographic Survey, 2001). A few calcareous conglomerates and limestone lenses within the watershed may also contribute to the relatively high ANC of Young Womans Creek (Mast & Turk, 1999)."

I fish w/ a pH test kit, sometimes see 2 streams in same bedrock formations have differences in pH and how well they seem to fish. even small sounding pH differences, 6.7 versus 6.4, seem to matter, but its a log scale so 6.7 = 1/3 the acidity of 6.4 ... more food so, if other things are equal, more fish...

 

[k-bob]

Scribbled-on image from paper by Kirby, Bucknell, on Groundtruthing showing how N Branch Buffalo Creek's pH increased over 2 mi travel thru juniata bedrock streambed. (A higher % of the NBBC drainage area is low-buffering tuscarora at the downstream location with higher pH, so this shows a streambed geology effect)

Kirby, C. S., McInerney, B., Turner, M. D., 2008, Groundtruthing and Potential for Predicting Acid Deposition Impacts in Headwater Streams Using Bedrock Geology, GIS, Angling, and Stream Chemistry, Science of the Total Environment, 393, 249-261

 

[Chaz]

The pH scale is logarithmic and inversely indicates the concentration of hydrogen ions in the solution (a lower pH indicates a higher concentration of hydrogen ions). This is because the formula used to calculate pH approximates the negative of the base 10 logarithm of the molar concentration[a] of hydrogen ions in the solution. More precisely, pH is the negative of the base 10 logarithm of the activity of the hydrogen ion.[2]

At 25 °C, solutions with a pH less than 7 are acidic, and solutions with a pH greater than 7 are basic. The neutral value of the pH depends on the temperature, being lower than 7 if the temperature increases. The pH value can be less than 0 for very strong acids, or greater than 14 for very strong bases.[3]
From wiki

 

[k-bob]

5.5 pH water has 10x acidity of 6.5 pH water. So a brookie stream with a pH of 6.5, because of its higher buffering geology, has 1/10th the acidity of a stream at 5.5. You see these sort of values, mid5s to hi6s, in NE PA brookie streams.

A 6.5 pH stream may have more bugs and fish even vs a similar stream at 6.2 pH, because the 6.5 stream has only 1/3 the acidity of a 6.2 one.

 

[Swattie87]

I’ve fished NB Buffalo Creek. It’s (or at least part of it is) Class A or high B from a survey I saw somewhere I think. Didn’t fish like it though. The section I fished is just off the map to the east, still in the forested section before it gets out into the valley floor. PH should be decent there right?

Caught a few Brookies, and one small Brown as I recall. This was in relatively good water conditions in late May, roughly 2013 or 2014 probably. Icing on the cake was a good bit of rhodo problems, as is common for streams in that area. Was a one and done for me. FWIW in terms of correlating map and PH data to fishing outcomes.

The main stem, also showed on the southern portion of the map in this thread with the very low PH’s, always looked appetizing on the maps, but I never fished it after reading similar studies about its acidity. Figured at those levels, it’s dead.

 

[k-bob]

I think I fished n branch buffalo once and recall rhodo... presence of a brown might suggest the stream is not too acidic. from the map above, the inputs of a few small tribs in that gnarly tuscarora bedrock might drop the pH of NBBC a bit over where you were.

interesting to note map's 4.1 pH versus 5.5 pH in Buff vs NBBC near their headwaters; these stream areas 1 mi apart.

 

[k-bob]

here's that map of tuscarora bedrock and pa streams again. given pH numbers in post 2 here, streams w tuscaraora bedrock influence seem unlikely for trout but they may be near streams in juniata bedrocks w better potential:

https://rpubs.com/mattshank20/tuscAD