blogger on thermal issues in DWGNRA streams

[k-bob]

http://fishinthefield.wordpress.com/2012/07/24/where-the-pool-stops/

 

[RyanR]

? This was an entry from July 2012 and the blogger talks more about the effects of the previous year's flood causing much of the issue regarding stream sections disappearing underground. I know right where some of those pictures were taken. It was amazing what the force of the water flow and rain did but it actually wasn't all from just the flood the previous fall, there were a couple more before it that began the "damage."

 

[Chaz]

I don't know how familiar this blogger is with those streams, but the Delaware River flows on glacial till pretty much from the headwaters to the water gap. What does this mean? Well there are places in the flood plain where this glacial till is nearly 300 feet deep. Many of the streams on the PA side sink, and in fact Dingmans Creek went underground several hundred yards upstream of the Rt. 209 crossing during the Ivan Hurricane.

There is a stream further north that's been sunk at least that long. All of these streams have trout in them to varying degrees, from Class A to just a few. Conashaugh is one I've never fished. I have fished some of the others. There are a number of streams in the Rec Area that are quite small.

It may not take much of a storm to make a stream along that road disappear.

 

[troutbert]

I think those streams have gone dry in their lower ends in low flow periods for thousands of years. The writer attributed it to the flood of 2011.

But, not only is it common for streams to sink down into the substrate in their lower ends in that region, it is very common in other places also. You see this a lot with small streams in NCPA.

It's worth knowing for practical fishing reasons. The stream you see at the road crossing in the lower end is often not at all representative of the stream as a whole. If you go upstream a ways you often see something entirely different, i.e. much better flows and better habitat.

 

[k-bob]

TB: "I think those streams have gone dry in their lower ends in low flow periods for thousands of years. The writer attributed it to the flood of 2011."

blog: "That pool is about 1.5km from where it meets the Delaware, is about 8ft deep, frigid in the middle of summer, and doesn’t resurface for another 500m+."

Conashaugh creek isn't just underground in its lower end down by the road -- the blog's photo caption notes that it goes underground 1.5 km (= about a mile) upstream from its meeting with the Delaware down by 209. The flood took out the road along the stream, so it may have changed the stream as well...

 

[troutbert]

I saw the same thing on several of those Delaware trib streams in the 1990s, long before the 2011 flood. I think it's a normal geological thing and has been that way for thousands of years.

And you see similar things in NCPA. The distance is sometimes fairly short, a couple hundred yards up to 1/4 mile. But sometime it's much longer, up to a mile or even longer than that.

 

[RyanR]

troutbert wrote:
I saw the same thing on several of those Delaware trib streams in the 1990s, long before the 2011 flood. I think it's a normal geological thing and has been that way for thousands of years.

And you see similar things in NCPA. The distance is sometimes fairly short, a couple hundred yards up to 1/4 mile. But sometime it's much longer, up to a mile or even longer than that.

Exactly. Attributing it to a single flood event in 2011 is the error in the blog entry. Otherwise I find it interesting and informative. I will say, just based on my observations there over the years, that the issue specifically of the area of Dingmans sinking I think was extended after several floods in the 2000s.

 

[Chaz]

troutbert wrote:
I saw the same thing on several of those Delaware trib streams in the 1990s, long before the 2011 flood. I think it's a normal geological thing and has been that way for thousands of years.

And you see similar things in NCPA. The distance is sometimes fairly short, a couple hundred yards up to 1/4 mile. But sometime it's much longer, up to a mile or even longer than that.

That is the point I tried to make. I've seen it further up on the Plateau in the Poconos, and there is a stream we all know that if you go far enough up you'll find a debris field in the stream where the water has disappeared, but when you go even further up there is flowing water from just below the ridge line all the way down to that debris field. It's been happening since there has been land and water.
And by the way, it doesn't usually raise water temperatures, it lower the temps. If there are elevated temps below the point of the debris it's more likely due to the full flow not returning to the surface, because the debris field extends much further downstream than can be seen.

 

[troutbert]

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