Recent genetic testing has detected the presence of hybrid milfoil in Sanford Lake. Hybrid milfoil is a cross between exotic Eurasian milfoil and native northern milfoil. In general hybrid milfoils are somewhat more resistant to certain herbicides compared to Eurasian milfoil. Genetic testing and herbicide susceptibility testing are both being done in Sanford Lake to help optimize treatment results.
How do the treatments impact fish?
If applied properly, herbicides have no direct impacts on fish. In general, lakes with a variety of plants often support more productive fisheries. The plant control program in Sanford Lake is designed to remove invasive plants while preserving plants that provide habitat and cover for fish.
Nuisance aquatic plant control is the primary focus of the Sanford Lake improvement program. In managing aquatic plants, it is important to remember that most plants are beneficial to the lake. Plants in lakes produce oxygen during photosynthesis, help stabilize shoreline and bottom sediments, and provide cover and habitat for fish and other aquatic inhabitants.
The objective of a sound aquatic plant control program is to remove plants only from problem areas where nuisance growth is occurring. Excessive removal of aquatic plants can have negative consequences. For example, broad-spectrum herbicide treatments can result in algae blooms and reduced water clarity which, in turn, can be detrimental to the fishery. Maintaining a diversity of beneficial plants is as important as controlling nuisance and exotic species.
Who determines when and where treatments and harvesting will occur?
When and where treatments and harvesting are conducted is determined by the weather and where nuisance plants are found when biologists from Progressive AE conduct their surveys.
Why are there still plants in the lake following treatments?
Not all plants are treated. The goal of the program is to strike a balance by controlling invasive plant species and maintaining beneficial species. We do not want to remove all the plants in the lake. This would be bad for the fishery and cause a host of other problems, such as massive algae blooms.
Is there a permanent fix to the problem?
If conditions are favorable, aquatic plants will grow. However, there are things property owners can do to help minimize the amount of plants in the lake such as limiting the use of lawn fertilizers and maintaining natural vegetation along the shoreline to act as a filter for nutrients that wash into the lake.
How about a pre-emptive strike?
To be effective, aquatic herbicides must be applied directly to the plant beds when the plants are actively growing. There are no approved pre-emergence aquatic herbicides like there are for agriculture.
Are herbicide treatments safe?
The aquatic herbicides that are permitted by the Michigan Department of Environmental Quality (MDEQ) are registered by the United States Environmental Protection Agency and the Michigan Department of Agriculture and Rural Development. They also undergo toxicological review by the MDEQ. In Michigan, aquatic herbicide use requires an MDEQ permit. The permit lists herbicides approved for use in the lake, respective dose rates, and shows specific areas in the lake where treatments are allowed. If herbicides are applied according to label instructions and permit requirements, they should pose no danger to public health and the environment.
A portion of the Sanford Lake aquatic plant survey map showing numbered GPS waypoints. Map provided by Progressive AE.
Why do the harvesters stop at the end of my dock?
Mechanical harvesters are large pieces of equipment and generally need two to three feet of water depth for operation. In addition, wind and wave action can move the machines and cause damage to moored boats and docks. For liability and safety reasons, harvesting equipment is generally operated along the end of docks into deeper water, and not in between docks and close to shore.
The Sanford Lake plant control program focuses primarily on invasive, exotic species. An exotic species is one that is found outside of its natural range. Exotic plant species that are potentially a threat to Sanford Lake include Eurasian milfoil, curly-leaf pondweed, and starry stonewort. Early detection and rapid response is key to effective control of invasive aquatic plant species. The Sanford Lake plant control program includes multiple plant surveys to detect invasive and nuisance plants and as well as targeted herbicide treatments and mechanical harvesting to control nuisance plant growth.
Who oversees the plant control program?
Plant control activities are coordinated under the direction of the board’s environmental consultant, Progressive AE. Beginning in May and continuing through August, biologists from Progressive AE conduct GPS-guided surveys of the entire lake to identify problem areas, and detailed plant control maps are provided to our plant control contractors. Progressive then conducts follow-up surveys to evaluate contractor performance, and provides regular status reports to the board.
Who conducts the herbicide treatment and mechanical harvesting work?
The Sanford Lake plant control program includes a combination of herbicide treatments and mechanical harvesting. Herbicide treatments and harvesting work is conducted by PLM Lake and Land Management, Inc. Both the herbicide treatment and mechanical harvesting contracts are competitively bid and performance-based. The contractor is only compensated for work that is performed satisfactorily.
Why didn’t my property get treated?
Treatments occur where the targeted invasive plants are found during the lake surveys. Not every property gets treated every time; your property may have plants, but if it doesn’t contain the targeted invasive plants, it’s not treated.
How will I know about use restrictions?
All lake residents will receive a written notice regarding pending treatments. The written notice will list all herbicides that may be used and use restrictions. At the time of treatment, state regulations require that areas within 100 feet of treatment areas be posted with a sign that lists specific herbicides applied and the associated use restrictions. If there is no sign posted along your property, it means your area was not treated and there are no use restrictions.
When is it safe to swim after a treatment?
All herbicides have a 24-hour swimming restriction that will be posted on signs along areas of the shore that have been treated. However, if you do not have a sign posted or the sign indicates that only algaecides were applied, there are no swimming restrictions.
When can I water my lawn following a treatment?
If you draw water from the lake for irrigation, be sure to read the sign posted along your shoreline at the time of treatment. Most irrigation restrictions do not apply to established lawns. However, it you water flowers or a garden, adhere to the irrigation restrictions posted on the sign.
In Michigan, a permit must be acquired from the Department of Environmental Quality before herbicides are applied to inland lakes. The permit lists the herbicides that are approved for use, respective dose rates, use restrictions, and indicates specific areas of the lake where treatments are allowed. In addition to a state permit, federal regulations require herbicide applicators to acquire a pesticide general permit and to prepare and submit a pesticide discharge management plan.
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