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Insight into Lake's Algae Blooms and Trees Growing in Lake Bed

Updated: Apr 9, 2022

The Glade Run Lake Conservancy often receives questions from community members regarding the lake's algae blooms as well as the trees that still remain in the lake bed, both of which can affect anglers and other recreationists who visit the lake. The following response from Timothy Wilson, Fisheries Biologist with the Pennsylvania Fish and Boat Commission, addresses these two topics and provides insight and understanding for those in our community who may have similar concerns.


Glade Run Lake is a shallow, eutrophic lake. This means there is an abundance (or over-abundance) of nutrients and minerals in the lake's sediments and in the incoming water. Glade Run Lake has a long retention time (i.e., the amount of in-flowing water is quite low compared to the total volume of the lake), which gives the lake a long time to utilize these nutrients to produce abundant vegetative growth consisting primarily of Eurasian watermilfoil (Myriophyllum spicatum), an invasive aquatic plant, and filamentous green algae.

Glade Run Lake was a shallow, eutrophic reservoir before the Pennsylvania Fish and Boat Commission drained it, and draining it hasn't changed that. You might recall that the Eurasian watermilfoil congestion was much worse before the lake was drained compared to what is there now.

Filamentous green algae in Glade Run Lake

One method to reduce aquatic vegetation is to prevent excess nutrients from entering the lake, which the Glade Run Lake Conservancy is working diligently to accomplish. However, there is a considerable amount of nutrient-rich organic material still in the lake bed, so Glade Run Lake will continue to have abundant (and sometimes excessive) aquatic vegetation now and into the future. It is the natural condition of shallow, nutrient rich lakes.

The other vegetation control methods available to the Pennsylvania Fish and Boat Commission (winter drawdowns and/or aquatic herbicides) would not be acceptable to the users of Glade Run Lake, given the recent history of the lake. Also, if we kill the weeds with herbicides, the nutrients will go somewhere and often the result is more algae, so treating one problem can make another problem worse.

I agree that fishing in and around abundant aquatic vegetation can be frustrating; however, there are angling techniques and fishing equipment designed to make fishing there easier and more effective. Summertime fishing in western Pennsylvania lakes usually means fishing in or near the 'weeds'.

A completely separate issue is the trees in Glade Run Lake. A good number of the trees were removed before the lake was refilled to keep most of the trees beyond casting distance from the shore and to provide corridors for travel to all parts of the lake. However, the vast majority were left in the lake intentionally to create fish habitat, and it is very good habitat.

Like most lakes constructed during this era (view the Glade Run Lake's history for more info), all of the 'stuff' that would have created good fish habitat was bulldozed from the lake bed when the dam was built. As a result, we were left with a lake devoid of fish cover, a key component of fish habitat.

Leaving in the trees that grew in the lake bed has given us an opportunity to create outstanding fish habitat, at no expense to the angler. This habitat should produce more and bigger fish for anglers to catch compared to what the lake would have produced if we had removed all the cover, as had been done in the past. Instead of avoiding the trees, anglers should be targeting the trees because this is the preferred habitat for the resident Largemouth Bass, Bluegills and White Crappie that inhabit the lake. Again, there are snag resistant fishing equipment and tactics that make fishing around the trees very effective. The trees don't have a negative effect on water quality.

Trees growing in lake bed at Glade Run Lake

View of trees in Glade Run Lake near fishing pier

The trees in Glade Run Lake are excellent fish habitat and The Pennsylvania Fish and Boat Commission doesn't intend to remove them. They will eventually rot away, but it will be many years before that occurs and that is what we intended when we decided to leave them in the lake. The best way to produce better fishing is to produce better fish populations, which is what the trees in Glade Run Lake do.

If you can't find a way to fish around the trees in Glade Run Lake, I would suggest fishing in nearby North Park Lake, which has no trees in it. It is also stocked with hatchery trout in the spring and contains good to excellent Largemouth Bass, Bluegill, Crappie and Channel Catfish populations. However, it is also a shallow eutrophic lake, so it experiences substantial aquatic vegetative growth in the summer.

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