A Message from Our Leader: Looking Back, Planning Ahead for Our Lakes

As the Leaves Fall, Harvesting Winds Down

When Communities and Harvesters Work Hand in Hand

What’s Really Happening Beneath the Water?

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Nutrient Management and Prevention of Algae Blooms
One of the most important benefits of fall aquatic weed harvesting is the removal of biomass before it decays. When aquatic plants die off, they decompose in the water, releasing nutrients such as nitrogen and phosphorus. These excess nutrients can lead to algae blooms in the spring, contributing to poor water quality, reduced oxygen levels, and even fish kills. By removing aquatic weeds in the fall, you prevent the buildup of organic matter and reduce the likelihood of nutrient overloads, helping maintain the delicate balance of the ecosystem.

Improved Water Clarity and Oxygen Levels
Decaying plant material reduces water clarity and depletes oxygen levels as it breaks down. Harvesting aquatic weeds before they die and sink to the bottom helps keep the water clearer and oxygen-rich, creating a more hospitable environment for fish and other aquatic species.

Aquatic Invasive Species Control
Fall is an ideal time to target aquatic invasive weeds, which often survive mild winters and can regrow more vigorously in the spring. By harvesting them in the fall, you disrupt their life cycle, reducing their chance of returning the following season. Early intervention prevents the spread of invasive species, preserving the native plants and ensuring a balanced aquatic ecosystem.

Ease of Access and Effective Timing
Many lakes experience lower water levels in the fall, making it easier to access areas that are otherwise submerged. This improved access allows for more thorough harvesting and reduces the effort required to clear overgrown areas. Additionally, fall is an optimal time for mechanical harvesting and sediment removal since the reduction in plant density allows equipment to function more efficiently.

Prepares the Waterbody for Winter and Spring
Aquatic weed harvesting in the fall sets up your lake or pond for better conditions during the winter and spring months. By reducing plant material and debris, the waterbody can stabilize over winter, preventing weed seeds from taking root and spreading. When spring arrives, you’ll notice less vegetation and fewer invasive plants, making it easier to manage and maintain a balanced aquatic ecosystem.

Fall aquatic weed harvesting is a proactive strategy that enhances the health and beauty of lakes and ponds. By addressing the buildup of aquatic plants and debris before winter, lake managers can improve water quality, protect aquatic life, and minimize the risk of algae blooms in the spring. The combination of mechanical removal and nutrient management ensures a healthier waterbody for years to come.

Aquarius Systems Aquatic Plant Harvesters

Curly-leaf pondweed is an invasive plant found throughout much of Minnesota. The plant grows slowly throughout the winter under the ice, but once the ice has left the lake the plants start to grow very rapidly. Curly-leaf pondweed gets a jump start on native aquatic plants, leading to dense mats on the surface by May or June. Sometime around mid-July, curly-leaf pondweed dies off and decomposes in the lake.

In the past, many lake managers thought that early treatment of curly-leaf pondweed might lead to better water quality and improved native plant populations. However, recent research has proven that large scale treatments in lakes with high nutrients levels did not produce water quality benefits or increase native plant populations.

Herbicide control is restricted to 15% of the littoral area of the lake, but mechanical harvesting allows for up to 50% of the littoral area of the lake to be harvested. A combination of both methods may be used as well. A limit on what areas to be treated or harvested insures that native plants, which provide water quality and fish and wildlife habitat benefits, will be protected.

A vital part of the area’s watershed, Carter Lake is a natural catch basin for storm runoff and melting snows. Excess nutrients being washed into the lakes leads to excessive aquatic plant growth.

The Aquarius Systems HM-1020 Aquatic Plant Harvester is the perfect solution for Carter Lake. The 1020 easily collected a full 16,000 lbs of cut vegetation in only 20 minutes of harvesting. This harvester holds so many weeds that it took two trucks to accept all of the harvested vegetation.

Curly-leaf pondweed is an invasive plant found throughout much of Minnesota. The plant grows slowly throughout the winter under the ice, but once the ice has left the lake the plants start to grow very rapidly. Curly-leaf pondweed gets a jump start on native aquatic plants, leading to dense mats on the surface by May or June. Sometime around mid-July, curly-leaf pondweed dies off and decomposes in the lake.

In the past, many lake managers thought that early treatment of curly-leaf pondweed might lead to better water quality and improved native plant populations. However, recent research has proven that large-scale treatments in lakes with high nutrients levels did not produce water quality benefits or increase native plant populations.

Herbicide control is restricted to 15% of the littoral area of the lake, but mechanical harvesting allows for up to 50% of the littoral area of the lake to be harvested. A combination of both methods may be used as well. A limit on what areas to be treated or harvested ensures that native plants, which provide water quality and fish and wildlife habitat benefits, will be protected.

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For 40 years – 1945 to 1985 – the sanitary district used herbicides, including 2-4-D for 17 years, in an attempt to control the weeds. Since 1947, the district also harvested weeds from the lake and would pick up the weeds that washed on the shoreline.

In 1985, the use of chemical herbicides was discontinued on the lake and an expanded weed harvesting program began. The harvesting and removal of the plant material reduced nutrients available for the regrowth of the invasive watermilfoil and allowed for a better diversity of native aquatic plants.

The Lake Pewaukee Sanitary District understands the value the aquatic plants have on the stability of the lake bottom as well as value the plants have on the aquatic life thriving in the lake. They also understand the importance of keeping the aquatic plant levels down to allow human recreation.

The District starts its harvesting program earlier than any other lake in Wisconsin and runs the program longer than any other lake in Wisconsin in an effort to knock back the invasive species and promote the native species. The challenge becomes what the budget and time allows and the cost benefit of what is being accomplished. The District has been slowly increasing the equipment and labor force in an effort to continuously improve the harvesting operations. Small budget increases are helping increase manpower and more importantly set up the 2nd shift program for years that the cycle provides a peak aquatic plant growth season.

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– Immediate relief from nuisance plants that interfere with navigation and recreation
– Immediate use of the water for swimming or irrigation
– There is nothing foreign introduced to the environment when using mechanical control
– Biomass is removed from the water and along with it the nitrogen, phosphorus and potassium that are bound up in the vegetation
– Harvesting does not kill the vegetation, but instead gives it a hair-cut, leaving behind living plants that continue to provide oxygen and habitat for the other organisms

– The living plants left behind continue to absorb the polluting nutrients that are used for growth
– Harvesting vegetation from the lake greatly reduces the tons of biomass that will eventually die and collapse at the end of the season. This biomass will decompose, consume oxygen, and release nutrients back into the water column to grow more weeds and algae in the future.
– Harvesting the biomass also reduces the build-up of muck and sediment on the bottom that occurs from the rotting weeds
– The Harvester is a tool to be used to improve the fishery. For example “Cruising Lanes” can be formed into certain weeds beds to provide access for fishermen, and for predator fish too; the predator fish will graze the edges of trimmed weeds beds to find prey.
– Over time plants become stressed and grow more sparse and shorter in height in frequently harvested sites
– Lake weeds make a great compost and soil conditioner. The decomposed vegetation compares to cow manure in terms nutrient content. Also, it contains no seeds that can grow on land.

– Harvesting is a highly selective process. Exactly where you steer the machine is exactly where the plants will be cut.
– Aquatic Plant Harvesters are available in many sizes with a variety of features to be customized to your application
– A Harvester is an essential tool in the lake manager’s tool box. It can be made to cut shallow or deep, narrow or wide, fast or slow, depending on what is needed.
– A Harvester compliments other lake management strategies, including herbicide use. For example, the canopy of vegetation can be harvested BEFORE a chemical treatment is done. This technique may save money because it enables the lake manager to use less herbicide. And it will reduce the negative environmental impacts of using chemicals by reducing the tonnage of biomass that settles to the bottom to decompose