Evergreen Lake Watershed Management Plan 25
The primary problem found in the Evergreen Lake watershed area is that
the level of phosphorus is too high. The Evergreen Lake Technical Committees
each addressed the sources of phosphorus and prioritized them.
The IEPA TMDL phosphorus limit level may or may not be attainable, and
as standards might be revised over the course of the implementation, the
planning committee met to address problems in the watershed based on current
regulations. Below are the problems addressed. The plan will strive to
implement strategies to work toward the current limits. Lack of data in many
areas acts as a significant detriment to planning, therefore data gathering is part
of future planning.
1. Phosphorus is entering the lake though sediment delivery from feeder
stream streambank erosion.
• Stream survey reports that over 90% of sediment entering Evergreen
Lake comes from within 4 miles of the lake.
2. Phosphorus is entering the lake through sediment delivery from erosion of
• The total estimated shoreline erosion in the lake is 2,300 tons annually.
3. Phosphorus is being released from the zero oxygen zone at deeper levels
of the lake.
4. Sediment containing phosphorus that would typically be inert on the lake
floor is being resuspended by the action of wind, fish and boat motor
movement in the lake.
• The 1997 Erosion Control Study presents a very thorough analysis of
the shoreline erosion on Evergreen Lake and concluded that the
primary cause of erosion is wind generated wave action.
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