Lakes Management FAQs

Why does my lake look like someone poured green paint into it?

The green color of many lakes in Lake County is the result of planktonic algae, a type of microscopic algae that floats in the warm, upper layer of the water column where it can receive adequate light. This surface “scum” can also be brown or red in color.

Algae Bloom

Planktonic algae are a normal part of every natural lake, but can reach nuisance levels if nutrients, especially phosphorus, become elevated in the water column. When this happens as a result of nutrient-laden runoff or nutrient release from lake sediment, an algae bloom can occur. The bloom causes the water to turn green and significantly reduces water clarity.

Reducing Nutrient Concentration

The most effective way to reduce algae blooms is to reduce the nutrient concentration in the water. This may be as easy as addressing the nutrients directly entering the lake through a creek, but typically, the nutrients are entering the lake via overland flow (non-point runoff) or via the sediment, which are much harder to control.

Reducing Non-Point Sources of Nutrients

However, there are ways to help reduce non-point sources of nutrients. These include reducing the amount of fertilizer applied to manicured lawns or using a low phosphorus fertilizer, and establishing buffer strips between manicured lawns and the lake shore.

Maintaining a Healthy Aquatic Plant Community

An additional way to reduce the frequency and severity of algae blooms is to maintain a healthy aquatic plant community in the lake. Aquatic plants compete with algae for light and other resources, while stabilizing bottom sediment to prevent nutrients from entering the water during sediment re-suspension. So if you keep your plants, you can reduce your algae.

If I’m seeing a lot of foam washing up along my shoreline, is it possible that someone is dumping detergent into the lake via wash water?

It is possible, but not likely. The more likely explanation is that you are seeing what is called “lake foam.” The bubbles are actually organic material in the water column that has been agitated by wave action into a foam-like substance. It is neither toxic, nor unnatural, and is seen on virtually every relatively large lake in the county that experiences wind or boat-driven wave action.

What does it really mean when a beach is closed? Why can’t I still swim?

The Lakes Management Unit tests all 9 Lake County Lake Michigan beaches every day of the week and all inland licensed beaches twice per month from May through September. The water at these beaches is tested for the bacteria, E coli, which is found in the intestines of almost all warm-blooded animals (i.e., birds, dogs).

The presence of E coli is an indicator that fecal material is present. Swimmers may have increased risk in coming in contact with harmful bacteria or viruses if the water is ingested.

EPA Standards

If a sample comes back “high,” it means there is more E coli in the water than is recommended by the U.S. Environmental Protection Agency standards and that it may be unsafe to swim in the water. If this is the case, those who manage the beach will be notified and a sign should be posted warning swimmers of the closure.

Additional Reasoning for Beach Closures

It is still safe for people to lay on the beach or picnic on the beach at this time, but many who do this often ignore the warning signs and continue to swim because it doesn’t appear that anything is wrong with the water. This may be dangerous, especially for young children who are more likely to swallow water at some point during swimming. If enough water is ingested, it could lead to many types of gastro-intestinal problems, including diarrhea, vomiting and cramping.

Why is it undesirable to remove all of the plants from my lake?

Aquatic plants are a natural part of every lake ecosystem and serve many purposes in a lake. Some plant functions include:

  • The production of leaves and stems that fuel the food web-they are a valuable food source
  • The production of oxygen through photosynthesis-they oxygenate the water via plant processes
  • Providing underwater cover for fish, amphibians, birds, insects and many other organisms
  • Providing a surface for algae and bacteria to adhere to. These organisms break down polluting nutrients and chemicals and are an important source of food for organisms higher in the food chain
  • Emergent plants break wave energy, reducing erosion of the shoreline, while rooted, submersed plants stabilize bottom sediment, reducing turbidity and nutrient cycling that can lead to algae blooms

Necessary Amounts

While it is not desirable to have a nuisance level of plants (especially exotic plants like Eurasian watermilfoil) that prevent the use of the lake by boaters and fishermen, the LMU recommends that aquatic plants be maintained along 30-40% of the surface area of the lake. This means that 30-40% of the lake bottom and water column contain rooted aquatic plants, not that 30-40% of the water surface be covered with plants. Over-treatment of plants with aquatic herbicides is a quick way to create a very murky lake, dominated by algae blooms. Herbicide treatments should be carried out with an understanding of the role plants play in the lake ecosystem.

Is it legal to put aquatic herbicides in my lake? Are they safe?

Yes, it is legal in the State of Illinois to apply registered, non-restricted use aquatic herbicides. However, you must own the portion of the lake bottom you are going to treat. If you do not know if you own the bottom, you must find out before you conduct any treatments.

Additionally, you must also ensure that the herbicides you apply to your portion of the lake bottom do not affect neighboring portions. This can be very difficult in aquatic situations due to herbicide drift (movement from one area to another). For these reasons, whole lake treatments can be difficult unless the permission of all bottom owners is obtained. In these situations, spot treatment of individual parcels might be a better choice.

Although it is legal for private homeowners to treat their own property, it may be best to hire an aquatic herbicide applicator to ensure the job is done correctly. They are professionals with the experience to know when, where and what herbicides are best suited for your lake and specific situation.

Like all aquatic plant management techniques, aquatic herbicides have both positive and negative characteristics. If used properly, they can all be beneficial to a lake’s well being. If misused or abused, they all share similar outcomes - negative impacts to the lake.

Aquatic herbicides are the most common method to control nuisance vegetation/algae. When used properly, they can provide selective and reliable control. Products cannot be licensed for use in aquatic situations unless there is less than a 1 in 1,000,000 chance of any negative effects on human health, wildlife and the environment. Aquatic herbicides are not allowed to be environmentally persistent, bioaccumulate or have any bioavailability. Prior to herbicide application, licensed applicators should evaluate the lake’s vegetation, choose the appropriate herbicide and treatment areas and apply the herbicides during appropriate conditions (i.e., low wind speed and temperature and high dissolved oxygen concentration).

My shoreline is eroding. Should I install a seawall?

Erosion is a potentially serious problem to lake shorelines and occurs as a result of wind, wave or ice action, or from overland rainwater runoff. While some erosion to shorelines is natural, human alteration of the environment can accelerate and exacerbate the problem. Erosion not only results in loss of shoreline, but negatively influences the lake’s overall water quality by contributing nutrients, sediment and pollutants into the water.

Seawalls are generally only recommended along very steep shorelines or those repeatedly battered by wave action and only when no other options are feasible. Seawalls provide neither positive aesthetics nor fish and wildlife habitat. Additionally, they generally reflect waves away from the shoreline and back into the lake. While this prevents shoreline erosion, it can actually create turbid conditions in the shallow water along the shoreline as the reflected waves re-suspend sediment into the water column. A more environmentally friendly alternative to a seawall is a buffer strip, which will hold soil along the shoreline effectively and may help filter upland nutrients and pollutants.

Should I have an aerator installed in my lake?

There are specific conditions under which installing an aeration system will alleviate problems in a lake. However, there are many misconceptions about what an aerator actually does and does not do, and when it may be beneficial to install a system into a lake.

What can be done about all the geese that live on my lake and are ruining my beach and lawn with their feces?

Canada geese (Branta canadensis) are migratory waterfowl common throughout North America. Geese in urban areas can be undesirable primarily due to the large amount of feces they leave behind. One study (Manny et al. 1975) documented that each goose excretes 0.072 lbs. of feces per day. This may not seem like a significant amount, but if 100 geese are present, that equates to over 7 lbs of feces per day! 

Contributing to Algae Growth

Goose feces are high in organic phosphorus, which can contribute to excessive algae growth in lakes. Increased development in Lake County has inadvertently created ideal habitat for goose populations. Manicured lawns mowed to the edge of lakes and detention ponds provide geese with open areas with ample food and security.


Although there are several options for getting rid of geese, very few, if any, of them have shown long-term success. The best thing to do is prevent geese from residing on your lake in the first place by establishing buffered shorelines.


Hunting is one of the most effective techniques used in goose management. However, since many municipalities have ordinances prohibiting the discharge of firearms, reduction of goose numbers by hunting in urban areas may not be an option. Contact the Illinois Department of Natural Resources (217.782.6384) for dates and regulations regarding the waterfowl hunting seasons.

Egg Addling

Egg addling, or destroying the egg by shaking, can be used to reduce or eliminate a successful clutch. Eggs should be returned to the nest so the hen goose does not re-lay another clutch. Egg addling requires a state and federal permit from the U.S. Fish and Wildlife Service (217.241.6700).


The capture and relocation of geese is no longer a desirable option because relocated geese may return to the same location where they were captured and there is a concern over potential disease transmission from relocated geese to other goose populations.

Dispersal/Repellent Techniques

Several techniques (harassment and chemical) and products are on the market that claim to disperse or deter geese from using an area. The goal with harassment is to frighten geese from an area using sounds or objects. Over time, these techniques may be ineffective, since geese become acclimated to these noise-making devices.


Another technique that has become popular is using swans to harass geese because swans are naturally aggressive in defending their territory, including chasing other waterfowl away from their nesting area. Since wild swans cannot be used for this technique, non-native mute swans (which are not as aggressive) are used.

Chemical Repellents

Chemical repellents can be used with some effectiveness. Several products can be sprayed to make the grass distasteful and forces geese to move elsewhere to feed. Another product has the additional benefit of absorbing ultra violet light making the grass appear as if it was not a food source. The sprays need to be reapplied every 14-30 days, depending upon weather conditions and mowing frequency.


Erecting a barrier to exclude geese is another option. In addition to a traditional wood or wire fence, an effective exclusion control is to suspend netting over the are where geese are unwanted. A similar deterrent that is often used is a single string or wire suspended a foot or so above the ground along the length of the shoreline. This technique will not be effective if the geese are using a large area as geese often learn to go around, over, or under the string after a short period of time.

Habitat Alteration

One of the best methods to deter geese from using an area is through habitat alteration. Habitats that consist of mowed turf grass to the edge of the shoreline are ideal for geese. Low vegetation near the water allows geese to feed and provides a wide view with which to see potential predators. In general, geese do not favor habitats with tall vegetation. To achieve this, create a buffer strip (approximately 10-20 feet wide) between the shoreline and any mowed lawn. Planting natural shoreline vegetation (i.e. bulrushes, cattails, rushes, grasses, shrubs, trees, etc.) or allowing the vegetation to establish naturally can create buffer strips.

Refrain from Feeding Waterfowl

Do not feed the waterfowl - There are a few "good things," if any, that come from feeding waterfowl. Birds become dependent on handouts, become semi-domesticated, and do not migrate. This causes populations to increase and concentrate, which may create additional problems such as diseases within waterfowl populations. Geese that are accustomed to hand feeding may become aggressive toward other geese or even people feeding the geese.

I'm worried about sediment entering my lake from a nearby construction site. What can I do?

Lake County has been growing and expanding very rapidly over the past decade and with that growth comes a large amount of new residential and commercial construction. While construction contractors are required to adhere to the regulations of Lake County's Watershed Development Ordinance (WDO) (PDF), at times, these regulations are not followed properly or are just not stringent enough to protect some of the county's higher quality lakes.

The Lakes Management Unit has recently become more involved with collecting water samples from several commercial and residential construction sites and intends on continuing this monitoring and collection as much as possible. However, we cannot collect data until we know that there is a potential water quality violation occurring.

If you notice very turbid water (looks like chocolate milk) running off of a construction site during a rain event, please call our offices at 847-377-8020. It is important to note that the Lakes Management Unit is not an enforcement agency and we can only collect data to pass along to those agencies able to enforce the WDO or water quality regulations. One of these enforcement agencies is the Illinois Environmental Protection Agency (IEPA), Division of Environmental Health. The IEPA may send someone out to investigate the complaint and will be more likely to act quickly if they are provided with total suspended solids (TSS) data (from our lab) and/or digital photographs of the water running off of the construction site and into a lake or steam.