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Sand Lake Plant Biovolume & Eurasian Watermilfoil Survey conducted by the Health Department, 2018
Aquatic invasive plants such as Curlyleaf Pondweed (CLP) and Eurasian Watermilfoil (EWM) are a common lake issue. Many homeowner associations contract with environmental consultants to manage these invasive species using herbicides. There are a few steps you can take as a lake and homeowner association to prepare you for the most effective treatments.
1. Have a pre-treatment aquatic plant survey conducted. This is an important step as it identifies not only areas of the lake with heavy plant abundance but also identifies which plant species are present. Native plants often do not need herbicide treatments as they are beneficial for a healthy lake ecosystem. Herbicide treatments should be focused on the aquatic invasive species such as CLP and EWM. Pre-treatment survey's can usually be done by your applicator but must be requested.
The map above is an example of a treatment map conducted by Lake County Health Department. Overall plant biovolume was mapped and it is displayed as a heat map with red colors showing higher abundance of plant biovolume and green colors indicating less plant biovolume. In addition, a rake survey was conducted to determine aquatic plant species present. On the map above, all white stars indicate EWM presence. Lastly, the boundaries of Eurasian Watermilfoil beds were mapped. In this lake, most of the plant volume observed was Eurasian Watermilfoil. With a good pre-treatment aquatic plant survey, treatment zones can be better identified and the lake can be more effectively managed.
2. Send out a request for proposal (RFP) for herbicide treatment. A RFP outlines the contract you would have you with your applicator. It is recommended to submit an RFP to multiple organizations so they can submit bids, which helps comparing the bids easier and you can make sure you are getting a fair price for your treatment.
3. Conduct a post treatment plant survey. The post treatment plant survey is an important step to assess the effectiveness of the treatment. Did it work as desired? Or will there need to be adjustments for future years?
4. Keep a detailed record of treatments and lake management. Keeping detailed records of your lake treatments is important in determining if your lake treatments are effective. Many variables can influence lake treatments but having a long-standing record of past treatments can help homeowner associations look at trends, effectiveness, and make adjustments as needed. This is also important because homeowner associations change leadership frequently. Records should be kept in writing and passed along when new board members or presidents take over the association.
Image from the Connecticut Department of Energy and Environmental Protection
There are generally three times of year when fish kills occur – winter, spring, and summer.
The winter fish kill is generally caused by low oxygen stress and more commonly occurs in very shallow, nutrient rich lakes. As a lake goes through turnover in the fall, it becomes fully oxygenated prior to ice up. The aquatic organisms consume the oxygen and while sunlight penetrates the ice, plants and algae produce oxygen. However, once snow covers the ice and blocks sunlight, less oxygen is produced than is being consumed through respiration by fish, plants, and bacteria decaying the organic matter. If there is a prolonged period of snow cover, fish become stressed as the oxygen becomes depleted and plants and algae are not able to produce oxygen. Also involved is a simultaneous rise in carbon dioxide from ordinary respiration of fish, plants, and bacteria and an increase in hydrogen sulfide, a poisonous gas, which is a product of bacterial respiration in the absence of oxygen.
Fish require less oxygen during the winter to maintain life. However, if the oxygen dips too low, and the carbon dioxide (which acts as an anesthetic to fish) rises to an anesthetic level, and hydrogen sulfide rises to a poisonous level, the fish get hit from three different directions at once, and winter fish kill occurs. In general, winter fish kills affect many sizes and species of fish.
Generally, the late winter and early spring thaws provids enough sunlight to recharge the oxygen supply. In a harsh winter with a lot of snow and extended period of ice cover, one of the best things to do is clear snow from several areas of the lake to allow sunlight to penetrate through the ice. Removal of at least 30% of the snow surface is usually adequate for sunlight transmission (Connecticut Department of Energy & Environmental Protection).
If a fish kill occurs on a lake or pond in your neighborhood it is recommended that the dead fish be collected and disposed of in the trash. Also, a fisheries survey should be done to see the extent of the damage done by the fish kill before any stocking program is initiated. If you have a local lake or pond that experiences a fish kill, please report it to the Lake County Health Department's Ecological Services at (847) 377-8020.
Midwest Aquatic Plant Management Society Conference: Feb 25-28, Chicago
The Midwest Aquatic Plant Management Society (MAPMS) invites you to register your attendance for the 39th annual MAPMS conference that will be held at the Palmer House Hotel-Downtown, Chicago.
Register now »
34th Annual Illinois Lake Management Association Conference, March 14-16, Crystal Lake Holiday Inn Conference Center
The conference will pack in 2 days full of technical presentations on all things lakes, watersheds, and water quality. Additional workshops extend the conference into a third day. This conference is a great opportunity for learning and networking. This year's keynote speaker is Dr. Gerould Wilhelm....yes, that Wilhelm, the Wilhelm of Swink & Wilhem. Come hear his talk on the influence of water within our landscapes, how it has the power to both physically shape our environment and our perception of living spaces.
Register now »
The 7th Annual Fox River Summit, March 22, Burlington, WI
The Fox River Summit is an annual gathering of organizations, municipalities, citizens, and stakeholders from across the Fox River Watershed. Building partnerships and developing an open dialog about the issues important to the management of the watershed is a key component of the Summit. The program features speakers and presentations highlighting these issues, but it is also an opportunity to celebrate the success of stories along the Fox River.
Register now »
Have you checked out our website recently? It's full of information on the lakes in Lake County. On our website you can find:
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Beach Advisories: Beaches are monitored from Memorial Day through Labor day. Lake Michigan beaches are monitored 4 days a week and inland lakes are tested biweekly. The water samples are tested for E.coli bacteria. If water samples come back high for E.coli (235 E.coli/100mL), the management body for the bathing beach is notified and sign is posted indicating the beach closures. Beach advisories and closures are listed on our website. You can also access historic beach data from our website as well.
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Bathymetric Maps: Bathymetric maps also known as depthcontour maps, display the shape and depth of a lake. They are valuable tools for lake managers because they provide information about the area and volume of the lake at certain depths. Bathymetric maps are available on our website.
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Lake Reports: Are you looking for the most up to date information on a specific lake? Check out our lake report section that shows the most recent data.
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Lake Mangement Planning Guide: Every lake is encouraged to make a lake management plan. To help, we've created a guide and template. Visit our website to have access to these tools.
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Facebook: The Health Department's Ecological Services has a Facebook group. Join to learn about upcoming events, ask questions, and more!
Clues
- Stems are stiff
- Have very coarse "teeth" along the edges
- The underside has a midvein
Think you know the answer? Email your best guess to ABartolai2@lakecountyil.gov.
Our Team
Mike Adam, Senior Biologist
Gerard Urbanozo, Water Quality Specialist
Alana Bartolai, Water Quality Specialist
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