Why Is the Lake So Low?

Glade Run Lake is looking a bit sad at the moment, all mud and stagnant banks. But ... there is a good reason for this.

Due to excessive algae growth on Glade Run Lake, this winter the lake will undergo a partial drawdown with water levels being lowered by about four feet.

This summer, a side effect of the drought and heat was an excessive growth of algae in the lake and on plants around the edge of the lake. By late summer, the lake was almost a total sea of green! To fix this issue and ensure the lake looks better next year, Glade Run Lake is undergoing a partial drawdown with water levels being lowered by about four feet. The fall trout stocking was also canceled. The lake is expected to be refilled over the winter to prepare for the spring 2026 trout season. 

Why the Drawdown is Happening

Drawing down a lake is an effective, non-chemical method for controlling excess aquatic vegetation by using natural forces—primarily desiccation (drying out) and freezing—during the winter months. 

Here is how the process works:

• Exposure: Lowering the water level exposes the shallow areas near the shoreline (the littoral zone) that are typically covered in weeds.

• Desiccation: The exposed plants and the nutrient-rich sediments they root in are subjected to air and wind, causing them to dry out. This damages the plant structure and integrity.

• Freezing: This is the primary control mechanism. Sub-freezing temperatures penetrate the exposed lake bottom, killing the plant's vegetative structures like roots, rhizomes, tubers, and winter buds, which are often resistant to cold when insulated by water.

• Physical Disturbance: The freeze-thaw cycles and the scouring action of ice can physically uproot and damage the plant systems, causing them to float away when the lake is refilled.

• Sediment Compaction: As the organic sediment dries, it compacts, which can increase water depth in shallow areas after the lake is refilled, making it harder for new plants to grow in the future due to reduced light penetration.

• Nutrient Reduction: Exposing and oxidizing the sediments can help to break down organic matter and reduce the overall nutrient load in the lake, which limits the "fertilizer" available for future plant growth. 

This method is particularly effective against plants that reproduce mainly by vegetative means (like milfoil). The success of the method is highly dependent on the severity of the winter weather, with cold, dry conditions offering the best results - so let’s hope we have a real cold winter. 

What to Expect

• Visitors will notice the water levels slowly decreasing over the next several weeks.

• The drawdown will impact the lake for a period, but is only temporary.

• The lake will be refilled during the winter to return to normal levels before the spring 2026 trout season. 

The Pennsylvania Fish and Boat Commission (PFBC) is managing this project and thanks the public for their patience.