Lake Management Plans (Eagle Lake) Page |
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They are described as: |
No Action- this method entails doing nothing to stop the spread of milfoil within Eagle Lake, allowing it to spread throughout the lake usually achieving a high density within the lake in 10 years. "The no action alternative is not a sound strategy for Eagle Lake ... The native plant assemblage provides far more habitat value than could any stage of milfoil growth..."(ENSR p20) |
Physical Methodologies- |
Benthic Barriers- Mats made using varying formats are laid out over the lake bottom to cover patches of milfoil, with weights holding them in place. The mats block the sunlight from reaching the plants underneath the mat causing them to die from a lack of photosynthesis, this also keeps plants from taking root where the mat is in place limiting the spread of milfoil. This is a non-selective method of weed control, and is not intended for use in large areas. |
Sediment Addition- this involves adding additional sediment to the lake bottom (or moving it from one location to anther) with the intent of making the bottom less hospitable for plant growth or to bury the plant. This method can be extremely disruptive to the environment, and is non-selective. |
Dredging and Excavation- this involves the large scale removal of sediment from the bottom of the lake to remove the offending plants. This method can be extremely disruptive to the environment, and is non-selective. |
Hand Harvesting- This is a highly selective method that involves hand removal of individual plants. This is labor intensive and highly effective method of removing plant biomass. It is not useful in large patches. |
Mechanical Harvesting- this form of control involving hydro-raking, roto-tilling or other mechanical removal methodology disturbs the surrounding bottom sediment and leaves the milfoil fragments free to propagate around the lake. |
Suction Harvesting- this variation of mechanical harvesting utilizes surface mounted water pumps (usually on a floating platform) to move aquatic plants into a collection hopper where they can drain. This has the advantage over mechanical harvesting of being readily usable by a team of underwater divers, and unlike dredging, suction harvesting minimizes the amount of sediment disturbance, as divers control where the end of the suction line is placed suction line is placed.
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Water Level Control- this involves draw downs of the lake to disrupt the growth of plants at varying water depths. Non selective and can be highly disruptive to native plant species. |
Herbicides- this is a relatively selective method that kills plants or limits their growth. Requires contact with the plant material and may decrease dissolved oxygen while plant matter decays. |
Biological Controls- this method involves the introduction of herbivorous fish or insects that feed on plant matter, or damage plants preventing additional growth. May be selective or non-selective, and provides “control with limited growth.” Care should be exercised when using some herbivorous fish as they have been deemed invasives or nuisances by the Illinois DEC; for more information see this USA Today article.
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