Sherman Lake &
Watershed Association
Unfortunately, there is not one single "magic bullet" strategy for weed management and water quality improvement. A successful approach will require a careful evaluation of all available strategies and most likely the application of a variety of tools.
This page provides a brief overview of available weed management strategies.  For more detailed information please visit our Lake Strategies Work Space.
Weed Management & Water Quality Improvement Strategies
Chemical Treatment
Chemical treatment is the most common and widely used strategy for weed management in inland lakes. The benefits of chemical treatment, when properly implemented, is immediate relief from problem species including Eurasian Water Milfoil and algea. The current chemical treatment program for Sherman Lake has been moderately to highly effective in controlling milfoil and algea.  Unfortunately, chemical treatment does nothing to address the root cause of excess nutrients in the lake.  This is why we have seen a rapid increase in the growth and spread of native pond weed, water meal and lily pads.
Mechanical Harvesting
Harvesting involves the physical removal of weeds from the lake using Heavy Duty Harvesters.  Harvesting has the advantage of removing some organic material and, therefore, nutrients out of the lake. Harvesting can be expensive. It is not uncommon for lakes the size of Sherman Lake to spend between $25,000 and $40,000 per year on harvesting programs.
Watershed Management and Non-Point Source Control
Watershed Management is a MUST DO strategy for any Lake Management Program that is interested in long-term results.  Watershed Management and Non-Point Source Control involves the careful evaluation and control of nutrient sources flowing into the lake. Solutions range from implementing the central sewer strategy to having all residents eliminate the use of lawn and garden fertilizers containing phosphorous - the key ingredient for accelerated lake weed growth.
Watershed Management is a long-term strategy for improving the health of Sherman Lake. Used in conjunction with other strategies it will pay dividends and save significant money by reducing the need for harvesting, chemicals etc.  To learn more about what you can do to support this strategy click here.
Dredging has been used for decades as an "option of last resort". Dredging has the advantage of actually addressing the root cause of internal nutrient loading by physically removing nutrient laden organic material and sediments from the lake bed.  Unfortunately, dredging is prohibitively expensive and difficult to obtain permit approval from the Michigan DEQ. Based on researching dredging projects for other lakes, a dredging program for Sherman Lake would most likely exceed $1million dollars spread over several years.
There is evidence that aeration combined with the use of specialized organic compounds can have a significant beneficial impact on reducing the nutrient load in the lake. Aeration strategies are designed to restore and accelerate the lake's natural ability to "clean itself" of nutrients like nitrogen and phosphorous. This strategy reduces weed and algea growth by limiting the available food supply the weeds and algea need to grow. There is also evidence that Aeration can reduce and reverse the accumulation of the "muck" on the lake bottom.
Implementing an aeration strategy on Sherman Lake would require a long-term commitment. Aeration is not cheap, but it is significantly less expensive than dredging. Academic opinion on aeration is mixed. Careful study of aeration as a strategy for Sherman Lake is warranted. There are several approaches and philosophies on aeration methods.  For a comprhensive review of the concept and theory behind whole lake aeration visit
Biological Controls
Eagle Lake in Paw Paw, Michigan has seen a reduction in milfoil growth using the milfoil weevil. The weevils are a species of insect native to North American that have a hearty appetite for milfoil. The weevils are harmless and nearly invisible to the human eye. In sufficient numbers the weevils can keep milfoil in check without the use of chemicals. It is possible that Sherman Lake already has a population of these weevils active in the lake.
Implementing this strategy would involve the introduction of many additional thousands of weevils into the lake and careful management of their ability to take hold and thrive in the lake and on the surrounding shoreline. To learn more about this fascinating bug visit: We will be investigating this approach and other biological control methods carefully over the coming months. For more information on other biological control measures visit:
Lake Drawdown
Lake drawdown strategies are often used to help mother nature kill the weeds in the winter and make it harder for them to re-establish the following spring.  Lake drawdown involves lowering the lake level by several feet so that the ice and freezing action can damage the root systems of the aquatic weeds and limit their regrowth the following year. Unforturnately, because Sherman Lake is a closed basin lake there is not a practical way to get the water out and back in, therefore, this strategy is most likely not a viable option for us.
Hypolimnetic Withdrawl
Hypolimnetic withdrawl essentially involves the siphoning off of water and, if possible, muck from the bottom of the lake. The intent is to remove the nutrient rich water and muck from the lake in a way that is less invasive and costly than dredging. This approach has, at best, shown mixed results. One significant barrier to implementing this strategy is the disposal of the water and muck that is removed from the lake. Obtaining DEQ permit approval for this strategy is a significant impediment.
Summary and Conclusions
Achieving results will require the application of a variety of strategies over the next several years. The focus for 2007 will be to maximize the impact of our management efforts within the confines of the current funding program. In addition, we will work to raise additional funds to implement a more comprehensive Water Quality Monitoring Program and test and evaluate more comprehensive strategies for implementation beginning in 2008.
Please take the time to review what you can do now to improve the health of the Lake and to understand the funding implications of implementing a more comprehensive program beginning in 2008. For a more comprehensive review of weed management and water quality improvement strategies, please visit our Lake Strategies Work Space which we are using to contiuously compile information and evaluate the potential of all available improvement strategies.
More On Lake Management...
Lake Management Plan
Overview of Weed Management Strategies
Funding Implications 
Know Your Weeds!
What We Can Do Now!
Water Quality Analysis
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