Lake Operations

Current Topics of Importance

Lake Improvement Projects


The Delavan Lake Sanitary District has been researching different technologies to help combat the nutrient levels in the lake. This year DLSD has been testing sludge reducing pellets. When the pellets are applied, they sink through the water column to the muck layer and activate, this activation process ensures the muck layer is populated with the necessary components (beneficial microorganisms, bio-stimulants, and vitamins) for optimal performance. Heterotrophic bacteria break down the organic compounds in the muck. This process releases carbon dioxide, water, and energy. Reducing muck accumulation in a water body can result in increased capacity, improvements in dissolved oxygen, and a reduction in nitrogen and phosphorous compounds. DLSD has been testing the pellets in high sediment areas such as: the Outlet, Inlet, Viewcrest, and Highlands.

The DNR and EPA has deemed this product safe for waterfowl and people, and do not require a permit at this time. Water samples and sediment levels are being taken regularly to ensure that we are getting accurate results. The pellet producer has committed to also provide monthly water and sediment testing by their microbiologist at no cost due to the large scale of the project.

The first initial results from the pellet tests have been positive and a reduction in muck has been seen. The results may be slightly skewed due to the large flood that took place in July of this year. That being said, DLSD is encouraged by the positive results and will continue applying and monitoring the new technology. Delavan Lake is a unique lake with a vast watershed; the District understands that it may take several different devises in order to maintain the health of the lake. DLSD will continue to weed harvest and utilize chemical treatments when appropriate.


If you are interested in personally utilizing the sludge reducing pellets, local suppliers are available. For additional information, questions, or concerns, please contact the District office at 262-728-4100.

Water Pennywort (Hydrocotyle Ranunculoides)

Have you seen this plant? 

Water Pennywort, or Hydrocotyle ranunculoides, is considered an invasive species in Wisconsin. This aquatic perennial can be found in shallow, slow moving water and on wet edges and mudflats of lake or pond edges. Water Pennywort prefers full sun to partial shade. The round, deeply lobed leaves reach the water surface from stalks attached to creeping stems. Small, green-white or green-yellow flowers develop in clusters in summer and early fall. This plant reproduces by runner stems and roots, seeds and stem fragments, and can develop large colonies.

The lake operations manager, Charlie Handel of the Delavan Lake Sanitary District, has found that the pennywort spreads quickly in September and closely monitors Delavan Lake during this time.

The WDNR and DLSD need your help. If you see Water Pennywort on your shoreline, or anywhere on Delavan Lake, please contact the Delavan Lake Sanitary District at 262-728-4100 or Heidi Bunk, WDNR, at 262-574-2130. Thank you for your dedication and support of our lake.




Blue-Green Algae

 Blue-green algae is often blue-green in color, but can also be blue, green, reddish-purple, or brown. It generally grows in lakes, ponds, and slow-moving streams when water is warm and enriched with nutrients like phosphorous and nitrogen. When environmental conditions are just right, blue-green algae can grow very quickly. It can be found in all lakes and rivers in Wisconsin, but they only become a problem when they form nuisance-level growths, called blooms. Most species are buoyant and will float to the surface, where they form scum layers or floating mats. In Wisconsin, blue-green algae blooms generally occur between mid-June and late September, although in rare instances, blooms have been observed in the winter, even under the ice.

When the conditions are right, blue-green algae is capable of making toxins that can cause illness for people and animals who accidently ingest or inhale water containing the algae, or those who have prolonged skin contact with the algae. According to the Wisconsin Department of Health Services, Division of Public Health, common symptoms of exposure to toxic blue-green algae include rashes, gastrointestinal aliments and respiratory irritation. People experiencing symptoms that may be due to blue-green algal exposure should contact their health care provider or the Poison Control Center at 1-800-222-1222.

Public health officials encourage people to avoid swallowing any water and to always wash off after swimming in any lake, pond, or river. Dogs should always be rinsed off with clean water to remove algae from their coat. If people have any doubts about the appearance of water, they should stay out. They should ensure that children and pets do not swim in or drink water with an algae bloom.

Animals have a higher risk of dying after exposure to blue-green algal toxins because they are smaller in size and may ingest large amounts of toxins from drinking lake, pond, or river water or licking algae from their coat. Symptoms in dogs can include lethargy, loss of appetite, vomiting, diarrhea or even seizures. If your animal shows any of these symptoms, contact your veterinarian immediately.

When trying to get rid of blue-green algae, do not treat the surface water. This will kill the algae but also releases the toxins into the lake and ponds. They best way to counter act these blooms is to reduce the amount of nutrients going into the water. This will take time and the communities help. Lakeshore home owners are encouraged to use lawn fertilizers only where truly needed, prevent yard debris from washing into storm drains, support local ordinances that require silt curtains for residential and commercial construction sites, and plant and maintain vegetation buffer strips along shorelines.

 For additional information, click on the links below:

Listed below are pictures and helpful identification tips provided by the Wisconsin DNR.  If you believe you have encountered a blue-green algae bloom, or have any further questions concerning blue-green algae blooms, please contact the Delavan Lake Sanitary District at 262-728-4100.



Delavan Lake Sanitary District Sponsors Healthy Lakes Grants


Healthy Lakes is a Wisconsin organization which was created to protect and improve the health of our lakes by increasing lakeshore property owners’ participation in habitat restoration, runoff control, and erosion control projects. They have five simple and inexpensive best practices that improve habitat and water quality on lakeshore properties. These practices are: diversion, rock infiltration, fish sticks, rain gardens, and 350 ft.² of native plantings. Healthy Lakes encourages people to implement any of these five practices on their own, but have come up with the Wisconsin Department of Natural Resources Healthy Lakes Grant for funding assistance. Eligible applicants would be local units of government, qualified lake associations, and others who can apply for funding on behalf of lakeshore property owners.

The Delavan Lake Sanitary District is proud to be sponsoring two awards to participating lakeshore property owners. The awarded grants do not exceed $1,000 and must remain in place for a period of 10 years from installation. The two grant recipients include: The Delavan Club Condominium Association, and lakeshore property owners Joseph & Carmen Trotta.

The grants will be helping the recipients with current runoff into the lake. As Delavan Lake is a drainage lake, everything that takes place in the Delavan Lake Watershed has either a direct or an indirect effect on our lake environment and water quality. The surface area of Delavan Lake is approximately 2,000 acres. The watershed area is about 26,000 acres. The Delavan Lake has a major runoff problem due to the surrounding area being 75% agricultural. Native grasses and wildflowers, as well as shrubs and trees, will be planted in an effort to improve wildlife, slow runoff water, and promote natural beauty.


Thank you to our participating grant recipients. Together we can safeguard our lake and ensure a healthy and prosperous future.  


For more information about how you can improve the water quality of the lake, and how to implement good shoreline practices, please visit the link below:'s%20Guide%20-%202011.pdf





Brown's Channel Grant


The Delavan Lake Sanitary District is pleased to announce they have received a grant from the State of Wisconsin in cooperation with the Wisconsin Department of Natural Resources for the Brown’s Channel Watershed.

The portion of the watershed that will be affected is approximately 300 feet south of the South Shore Drive weir, within Delavan Lake’s Brown’s Channel area. This section of the watershed has deteriorated due to the amount of woody debris that has fallen in the stream, subsequently promoting channel alteration and degradation. The stream bank has been observed to contain many undercut areas with considerable erosion. This area is now home to many invasive plants, which have overgrown and displaced significant percentages of native vegetation. 

With this grant, the Delavan Lake Sanitary District will be able to address many problem areas with the Brown’s Channel sub-watershed. The removal of woody debris blocking the channel and the repair of damaged stream banks is hoped to improve the flow and remove trapped soft sediment from the stream bed. It is anticipated that a rockier substrate will allow impacted macro-invertebrate populations to recover and thrive, which in turn will provide fisheries habitat. Stream habitat improvement will decrease sediment load, reduce nutrient run-off from agricultural fields and provide better habitat for native species. Out of the approximate 1,200 feet of stream bank located within the property about 26% is in need of some degree of stabilization and protection.


Wisconsin DNR grant funding is crucial for the Delavan Lake Sanitary District. The grant funding helps provide protection to our delicate ecosystems, recreational opportunities, waterfront property values, and enjoyment for current and future generations.




 Purple Loosestrife: It’s A Pretty Big Problem

Between July and September, you may notice a tall, bushy plant with very attractive magenta colored flowers growing along your shoreline, perhaps in a wetland, along a wet ditch area or maybe in your garden. This striking plant is tall enough to shield unwanted views and grows with little or no care so the uninformed might see it as a charming shrub. But once the facts are presented, it becomes very clear that this plant, Purple Loosestrife, Lythrum salicaria is nothing but trouble.

A native of Europe and Asia, Purple Loosestrife was introduced in the United States as a garden plant. It reproduces predominantly by seed however reproduction by roots and underground stems is also common.  Due to rapid reproduction (a mature plant can produce up to 3 million seeds), vigorous growth and lack of natural predators, Purple Loosestrife quickly escaped cultivation and has since invaded many of our valuable natural areas.

Purple Loosestrife can take over wetlands and lakeshore areas within a few years. These natural areas are important habitat for many native species of plants, birds, insects, amphibians, and animals, which often disappear when Purple Loosestrife outcompete the native plants in an area. Purple Loosestrife is so detrimental that is has been added to the Wisconsin’s Invasive Species law, Chapter NR 40 as a restricted species. As a restricted species, it is illegal to transport, transfer or introduce all cultivars, hybrids and varieties of Lythrum salicaria and L. virgatum.

In order to prevent new infestations it is important to identify and  eliminate large and small populations of Purple Loosestrife.  If care is taken to minimize soil disturbance, single plants or small populations can sometimes be carefully dug out and disposed of. It is important to make sure all of the root is removed or new shoots will grow. Once plants start to flower it is important to remove the flowering stalks carefully and dispose of them away from water. This is done by bending the flowering stalk into a bag and cutting it so that it falls into the bag. Allow the plants to dry and burn if possible so that seeds do not disperse. On large sites, chemical control may be an option. If the  Purple Loosestrife is growing near  water, a DNR permit may be required and the chemical may need to be one that is acceptable for use on water. For more information about aquatic plant management and control visit the WI. Department of Natural Resources (DNR) website at and/or contact Heidi Bunk, DNR Water Resources Management Specialist at (262) 574-2130. Using either control method will require continued monitoring and control efforts because seeds in the soil will continue to germinate for several years.

In larger, more severe infestations, manual and chemical control may be too expensive or labor intensive. However, the use of specially selected and highly tested insects that feed on Purple Loosestrife have been shown to be highly successful. This method is known as biological control (biocontrol) and research has shown that these specialized insects reduce both plant height, seed output and overall plant numbers. This allows other, native plants to regain control in a few years. Wisconsin DNR and UWEX have created a program in which hundreds of citizens have raised and released millions of beetles that feed on Purple Loosestrife. For more information about Purple Loosestrife biocontrol, contact Brock Woods, WI Purple Loosestrife & Wetland Invasive Plant Program Coordinator at (608) 266-2554, email at            

For those gardeners that enjoy the magenta flowers, there are several attractive alternatives, such as: Blazing star, Liatris pycnostachya. Foxglove, Digitalis purpurea, Obedient Plant, Physostegia virginiana and  Steeplebush, spiraea tomentosa. These, and a few other look-a like plants can sometimes make identification difficult. For assistance with identification of Purple Loosestrife in Walworth County, please feel free to contact Audrey Greene, Lake Specialist & Aquatic Invasive Species Coordinator at 262-741-7902 or                                                                                                                                                                                                                    

Citizen Lake Monitoring for the Future of Your Lake

The Citizen Lake Monitoring Network (CLMN), formerly Self-Help Lake Monitoring, is a collaboration between citizen volunteers and the Wisconsin Lakes Partnership (Wisconsin DNR and UW-Extension and Wisconsin Lakes) that began in 1986 as a means to involve citizens and increase lake protection.  There are currently over 1200 CLMN volunteers in Wisconsin collecting information about their lakes. The work is unpaid, but the results are invaluable. As monitors work on their lakes, they acquire knowledge that helps them become more effective at protecting their lakes. They also collect data that very likely would not be collected without them, because there is simply not enough DNR staff available.

CLMN volunteers may choose to monitor for water clarity using a Secchi disk or they might be interested in collecting water chemistry data.  Some monitors decide they would rather learn to identify and map native aquatic plants, while others prefer to look for one or more of the aquatic invasive species (AIS) that threaten their lake. The decision is totally up to the volunteer but whatever their choice, or choices, the DNR and UW-Extension CLMN staff provide the equipment and training.

There are currently 23 lakes in Walworth County that have water quality data on the DNR website thanks to volunteer monitors. Depending on the lake, this data may go back for more than 20 years. Anyone that is interested and has access to a computer can easily find all water quality monitoring data on the by visiting the DNR website lakes page at and then clicking on “Lakes A-Z”.

In recent years many CLMN volunteers have started monitoring their lake for new AIS introductions or tracking existing populations of AIS to protect their lakes.  It is well known that AIS can cause large problems on lakes. Aquatic invasive plants can clog boating lanes and diminish recreational opportunities Aquatic invasive plants and animals reduce essential habitat and out compete native species.  The economic damage to taxpayers for management of the AIS that are currently in Wisconsin waterways is currently several million dollars per year. New AIS will mean higher costs, however, finding new populations of AIS before they become established has been shown to lower control costs and provides a much higher possibility of eradication.

Through the CLMN training, volunteers are taught to monitor their lake for one or more of a variety of AIS. They will learn where and when to look for the species they decide to monitor and what steps to take if they discover a suspicious plant or animal. Volunteers do not need to have any previous experience or knowledge of AIS. They also do not have to devote a huge amount of time. An hour or two once a month through the boating season is more than enough for most species and several species require considerably less time than that. Some monitors look for AIS by checking at boat ramps and beaches. Others look in deeper water areas. It is entirely up to the volunteer to decide what they want to do. 

The lakes in this county are some of our most precious natural resources and they need the best protection we can give them. Educating lake users about AIS and prevention methods has increased protection but we can always go one step more. Please consider becoming a CLMN for AID monitor on your lake.  If you have questions or would like more information please contact Audrey Greene at (262) 741-7902 or

     New AIS Fact Sheets


Aquatic Invasive Species




Pier Pick-Up Dates:

Main Lake   -  June 5, 26 - July 10, 24 and August 7, 21

Inlet/Outlet  -  June 6, 27 - July  11, 25 and August 8, 22

                       Starting at 6:00 am. (all dates are weather permitting)

The request for Pier Pick-Up must be called into the office before 9:00 pm the Sunday before the pick-up date.  262-728-4100 (the recorded message will give you instructions) Your pier must be numbered or identified in such a manner that we can locate it.

Pier Pick-Up is for aquatic plants only and must be placed at the end of the pier and clearly visible to the Harvesting Crew.  We will not pick up plants mixed with rocks, lawn or garden debris, branches, garbage, etc.

Aquariums & Aquatic Invasive Species (AIS)
As fall winds down and winters cold temperatures freeze the lake, those of us that love the water look for other ways to experience the pleasure of it. Many people find that the underwater world of aquariums do provide the relaxation and beauty they crave.
Pet stores and internet sources make setting up and populating an aquarium easy and fun, but aquarium enthusiasts need to be aware that Chapter NR 40, Wisconsin’s Invasive Species Identification, Classification and Prevention law has resulted in the regulation of some popular, but highly invasive, aquarium plants.  Several of these prohibited and restricted plants are sold through the internet and out of state sources. They are often promoted as species that will beautify and oxygenate your tank, and while they may indeed be beautiful, they could cause huge problems for Wisconsin waterways.  Below is a list of popular aquarium plants that are prohibited or restricted. Prohibited species may not be transported, possessed, transferred or introduced in Wisconsin. Restricted species may not be transported, transferred, or introduced in Wisconsin.
There are many aquarium plants that are not listed as AIS in Wisconsin so there will be no shortage of attractive plants for aquatic gardeners to enjoy. Regardless of whether or not an aquarium species is regulated in Wisconsin, never dump any plants, fish or animals into any lake, pond or stream. Besides the fact that it is illegal and the fines are quite large, they could do immense harm to our waterways.
To further protect Wisconsin from AIS, verify the scientific names of any aquatic plants purchased and inspect all shipments/purchases to ensure that the plant ordered is indeed the plant received and that there are no ‘hitchhikers’ included. Dispose of unwanted aquarium species responsibly. Check with your retailer for possible returns or bag and throw in the trash.

Aquatic Invasive Plants sold for aquariums

Scientific name

& Synonyms

Common Name(s) Notes
Cabomba caroliniana Fanwort, Carolina fanwort Prohibited; submersed perennial; native to southeastern United States; often confused with water milfoils and water buttercup
Crassula helmsii Australian stonecrop, New Zealand pygmyweed Prohibited; sold as an oxygenator for ponds and aquariums
Egeria densa Brazilian waterweed; Brazilian elodea Prohibited; sold as an oxygenator for ponds and aquarium; native to South America; may be confused with Hydrilla verticillata and Elodea nuttallii
Hydrilla verticillata Hydrilla; water thyme; Florida elodea Prohibited; submersed perennial; native to Asia; introduced to Florida in 1958 as an aquarium plant; may be confused with Elodea canadensis, Egeria densa
Hydrocharis morsus-ranae European Frog-bit Prohibited; Free-floating perennial; can be confused with water lily and Limnobium spongia
Lagarosiphon major Oxygen weed; African elodea, African waterweed Prohibited; submersed perennial; may be confused with Elodea Canadensis and Elodea nuttallii
Myriophyllum  aquaticum Parrot feather Prohibited; submersed perennial; may be confused with other milfoils
Myriophyllum spicatum Eurasian water milfoil Restricted; submersed perennial; may be confused with other milfoils
Najas minor Brittle, lesser, bushy, slender, spiny and minor naiad; waternymph Prohibited; submersed annual, reproduces by seed and fragmentation; easily confused with native Najas spp.
Nymphoides peltata Yellow floating heart Prohibited; bottom rooted perennial with floating leaves;
Potamogeton Curly-leaf pondweed Restricted; submersed perennial; introduced as an aquarium plant
Trapa natans Water chestnut Prohibited; annual floating leaf emergent

 For more information see the Wisconsin Department of Natural Resources website at, or contact Audrey Greene, Walworth County Land Use & Resource Management at 262-741-7902 or




Our plans for mechanical harvesting remain much the same as past years.  We intend to launch our harvesting equipment the week of May 19th and begin the initial harvesting of plants in the access channels at that time.  After June 15th we will harvest all areas of the lake as conditions warrant.  

For those of you who would like more information on zebra mussels here are some web sites to check:

 Blue-Green Algae In Wisconsin Waters


New regulations regarding the placement of Piers in Wisconsin waters has gone into effect and an overview of these regulations can be found at:


Town of Delavan has a new Bouys/Rafts Permit