By Andy McAllister, Watershed Coordinator and Bruce Golden, Regional Coordinator

The editors of Abandoned Mine Posts (AMP) recently caught up with Mark Killar, Director of Watershed Services with the Western Pennsylvania Conservancy and asked about the possibility of trout living in AMD-impacted streams.

AMP: Redstone Creek in Fayette County is a stream that runs orange for many miles from huge abandoned mine discharges, yet we’re aware of reports of rainbow trout being caught there. Could that be? Is it a fluke or are they fish that someone dumped into the creek?

Killar: This kind of scenario has been observed in other streams that receive net alkaline Abandoned Mine Drainage (AMD) from abandoned deep mines. As you may be aware, these discharges often contain high amounts of alkalinity due to the limestone layer located above the flooded portion of the mine(s). Although the discharges look ugly because they contain lots of iron and turn the stream orange, they don’t contain acid or aluminum, the two deadly killers of fish and life in the stream. Because fish aren’t affected that much by iron, they can survive in these net alkaline iron polluted streams.

AMP: So, some discharges aren’t as toxic as others? Is it possible that some of these discharges could actually help fish populations?

Killar: Well, one thing that helps out trout in particular is the 50 degree water temperature of the mine water. Especially at low stream flows, the mine discharges have a positive effect on the stream by keeping the water temperature down because they often can make up a significant portion of the stream flow when the streams are usually flowing low. Cooler water means the stream can hold more oxygen, which the trout like and need. Besides that, people wouldn’t normally think there are trout in the orange water so they don’t fish there and the trout get a chance to grow.

AMP: You said that “fish aren’t affected that much by iron”. Does that mean we should simply not be concerned about water that’s just polluted by iron then?

Killar: A study was done on Sewickley Creek some years ago (which also has several large alkaline deep mine discharges on it) and to the surprise of the person doing the study several nice brown trout turned up in a little orange tributary to the stream. It was a very small stream that looked ugly as heck, but again, didn’t have acid or aluminum being dumped into it from the mine discharge. Upon further study, it turned out the fish only had minnows in their stomachs and no aquatic insects, which makes sense in that the heavy coating of iron on the bottom of the stream significantly reduces the number of aquatic insects because it smothers out their habitat.

The big question is “What the heck are the minnows eating to keep them alive?” One theory is they come from the smaller unpolluted tributaries or are washed into the unpolluted sections from upstream.

A similar situation happened on Loyalhanna Creek near Latrobe where again large net alkaline deep mine discharges polluted it and turned the stream orange. One local fisherman had a secret spot he would fish (in the orange portion of the stream) and would catch some pretty large fish. Again, it was likely that few fisherman would consider fishing in that portion of the stream so the fish had lots of time to grow big.

Visit the Western Pennsylvania Conservancy’s website for information about conservation activities in the Western part of Pennsylvania.

A listing of watershed groups in Western Pennsylvania is available online.

(Reprinted from Abandoned Mine Posts, Western Coalition for Abandoned Mine Reclamation.)

9/22/2007