Wakeboats and Rock Lake

There has been a simmering conversation about wake boats in Wisconsin: numerous newspaper articles; multiple on-going hearings by the Wisconsin Natural Resource Board (NRB); votes through the Wisconsin Conservation Congress; lobbyists; a coalition of state-wide non-profit organizations including: Wisconsin Wildlife Federation, Walleyes for Tomorrow, Wisconsin’s Green Fire, Wisconsin Lakes, Last Wilderness Alliance, Lakes at Stake Wisconsin; and failed state-wide legislation attempts.

Wake boats are water-sport tow boats that are designed to create large wakes for rope free surfing and other water activities. There are concerns that these boats may impact the safety and enjoyment of other lake users such as kayaks, stand up paddleboard (SUP), swimmers, idled boats, and fisherman due to swamping, overturning, and increased chop. The concerns also extend to ecological impacts such as damage to fish habitat, the increased possibility of algae blooms and murky water, as well as damage to shorelines, piers, and lifts.

Some local governments have restricted or prohibited the enhanced wakes created by wake boats. Such restrictions/prohibitions may encourage more wake boat use on unrestricted lakes, such as on Rock Lake. 

For the next four weeks, RLIA will provide information on: what are wake boats, the recreational and ecological impact of enhanced wakes, where Rock Lake’s wake traffic might come from, how the National Marine Manufacturer’s Association plans on addressing concerns; local community regulation; state-wide regulation; and RLIA’s voluntary wake sport zone. A community presentation on 8/17 at the Korth Park Upper Pavilion at 10am will also be held. Afterwards, we will ask for feedback from our membership, and our community as to appropriate actions that reflect public values. In the meantime, checkout this short YouTube video: https://www.youtube.com/watch?v=2OEHn0Htj8A

Wake boats can create high standing waves designed to allow someone to surf, rope free, behind the boat. These waves are created by taking on lake water as ballast (up to 5000 pounds or 600 gallons); operating “off-plane” at low speeds (10 mph) with the bow up and stern down; and utilizing specialized fins or wedges, attached to the boat’s stern, to shape the wake.  The weight of the ballast is the weight of an average mid-size SUV.  The boat stays in bow up plowing mode the entire time someone is surfing, so the propeller is angled down about 30 degrees below horizontal (boat angle plus propeller shaft angle). A powerful 350-600 hp motor is needed due to the heavy ballast and very inefficient plowing mode. If the boat does not take on ballast, wake boats can also operate like a traditional water-sport tow boat. 

According to Jesse McArdell, policy manager for the National Marine Manufacturers Association (NMMA), wake boats first came onto the water sports scene in the early 2010s.  Popularity surged during the pandemic. Recent sales figures show wake boats represent 4.6% of all new powerboats sold in the US, and nearly 90% of boats with inboard motors. There are also after-market products which can be added to other boats to help create enhanced wakes.

For other recreational users, there are two concerns with wake boats operating in a mode that requires ballast, baffles, or other devices to create an enhanced wake.  The first issue is the bow up stance which makes it difficult to see other boats, swimmers, and recreational users who are temporarily in the water.  Mastercraft, a manufacturer of wake boats, recommends in their wake boarding guide: “Make sure the lake does not have other water sports or swimmers present at the same time. Not only can it be cumbersome to watch out for other vessels, but a collision can cause serious damage and injury.”

The second issue is the size of  enhanced wakes which can: swamp other boats, kayaks, and stand up paddleboards (SUPs); disturb fishing boats; and endanger swimmers.  Rock Lake has seen an increase in the number of paddle sports users. Sandy Beach now rents kayaks and SUPs.  In the last few years, a significant number of fishermen are using low profile boats. These boaters are blindsided by huge waves, still over a foot high from a wake boat that never came within a football field of them (300 feet). Fishermen are particularly vulnerable– they are often standing to cast, facing shore, anchored, and unaware that a huge wake is about to hit the side of their boat. Even people in large boats who see the wake coming in time to turn into it have been tossed, injured, and soaked, and their boats damaged. Waves lose very little energy as they travel over deep water.

Currently, on Rock Lake, motorized watercraft are required to leave 100 feet between their vessel and the shoreline, piers and swimming areas.  Personal Water Craft (PWC/Jetskis) have to operate 200’ from shore and 100’ from another vessel. Given the significant difference in the wave energy created by wake boats, their impact on other users is magnified.  In addition, multiple passes of a single wake boat, or multiple boats, can create a cross-hatch of waves which are difficult to navigate.

Here’s a video of a child stranded atop a slide on Lake Keesus in Waukesha county: https://youtu.be/OU_h6XSIHfQ.  After a wake boat passes nearby, divergent waves build as they traverse ever-shallower water battering a floating swimming platform, as well as the bottom of the child’s slide. Lake Keesus is just northeast of Oconomowoc.

According to an avid Rock Lake fisherman, the yellow areas on this map are places where he has seen fish spawn. The dark blue areas are changes in depths or ledges where fishing is particularly good (typically 10-25 feet in depth). Rock Lake’s lake bed also has a variety of substrates with some areas like Korth Bay being very mucky, other areas very sandy, still others with cobble and gravel. The design of wake boats with their downward-angled propellers, direct more energy downwards towards the lake bed. This energy can scour the bottom, re-suspending sediment which can coat fish eggs and eventually kill aquatic plants. Although aquatic plants are sometimes viewed as a nuisance by boaters, they are the bedrock of a lake’s health. Without them, the entire lake’s ecology is damaged including everything living in Rock Lake. Once the lake bed is disturbed, or fishing habitat is destroyed, it is almost impossible to remediate. According to Mike Arrowood, State Chairman of Walleyes for Tomorrow, “We’ve gotten reports from around the state the past year that are troubling. Many underwater humps and reefs that previously held beneficial vegetation are now bare. Vegetative flats are also getting destroyed. Of further concern is a potential decline in needed dissolved oxygen levels, due to sediment disruption. We need action, and now.” Scouring also releases phosphorus which can feed and enhance algae blooms. The suspended sediment also increases the water’s murkiness, reducing water clarity. University of Minnesota, St. Anthony Falls has conducted research on what depth wake boats should operate in to minimize damage to the lake bed. The resulting manuscript is in peer review and is expected to be published sometime this fall. Preliminary results indicate that depths of at least 30 feet are adequate.

Wake boats can create large wakes because they take on large amounts of lake water for ballast (up to 5000 pounds or 600 gallons).  The design of the tanks makes it impossible to completely empty them. Manufacturers recognize this fact since owners’ manuals recommend adding several gallons of antifreeze in winter to prevent the residual water from freezing and causing damage. When ballast is filled and emptied in a different lake, that residual water and any invasives are then transferred. Lake invasives can exist in these tanks for long periods of time because the tanks do not dry out.
Transporting this retained ballast is a violation of two Wisconsin state laws: Wisconsin Administrative Code NR 19 which requires all boats to drain water from the boat and all equipment, and Administrative Code NR 40 which prohibits transfer of invasive aquatic plants and animals between lakes.  Unfortunately, Wisconsin water patrol officers believe they do not have “probable cause” to stop a wake boat from entering a lake to demonstrate that it’s tanks are empty because there is no visible evidence that there’s retained lake water in the tanks.  This Catch 22 enables wake boats to carry several gallons of water between lakes.

What’s the risk? One species that is of particular concern is the spiny water flea. When the population of spiny water flea exploded in Lake Mendota, the lake lost three feet of water clarity! Currently, Rock Lake does NOT appear to have this invasive species.  However, thirteen percent of incoming boats to Rock Lake come from infested waters.
Other states continue to search for answers in addressing this transfer of invasive species.  In April 2024, Vermont passed a state-wide ordinance requiring wake boats to declare a “home lake” for a calendar year and display a Home-Lake decal on their bow.  Any wake boat leaving their home lake must show documentation that the ballast tanks were decontaminated before entering another lake. Decontamination is difficult and expensive, requiring lots of hot water and a trained operator. Here’s a video by Pacific States Marine describing the decontamination process (2 mins): Ballast Bags Decontamination Groups continue to pressure the industry to solve this issue not just for new boat designs, but also to retrofit all the boats they have already sold.

Residents have been water skiing on Rock Lake for more than fifty years.  They have been towing children in tubes behind their pontoons for decades. Since 1973, boaters have operated in a slow no wake manner within 100 feet from shore. (In 1997, Personal Water Craft (PWC/jetskis) were regulated to operate 200 feet from shore.) According to peer reviewed, scientific research from the University of Minnesota, St. Anthony Falls, waves created by wake boats have much more energy than waves created by other tow-boats or the wind. Their research used real boats, operating on water, with underwater measurement equipment. Their research demonstrated that for an enhanced wake to have the SAME, minimal, impact as any of these other activities operating 100 feet from shore, a wake boat would need to operate 600 feet from shore.  If the enhanced wake is created closer to shore, it will transfer its excess energy onto the shoreline causing possible damage to piers, lifts, and boats, as well as the shoreline itself. On Rock Lake, the effects of enhanced wakes will be most acutely felt by riparians along the City’s side (east) and a small number of riparians along Shorewood Hills Road since there are no other boating regulations pushing wake boats further off shore. 

University of Minnesota’s research is highly regarded and often referenced nation-wide.  View an interview with one of the researchers: https://youtu.be/nFLTho8KOgs

Wake boats access Rock Lake waters either as out-of-town boaters, residents who use public launches, or from owners who live on the lake. Anecdotally, there does appear to be more boats creating enhanced wakes on Rock Lake this season. In March 2024, the Town of Oakland banned artificially enhanced wakes on Lake Ripley. According to the boat inspectors at Rock Lake launches, boaters from Lake Ripley visit Rock Lake frequently (19% of incoming boats).  Lake Delavan (3%) is studying wake boat volumes with drone fly-overs, and Lake Geneva (3%) continues to study the issue as well. Unfortunately, we have not been able to specifically track the number of wake boats coming into Rock Lake. 

The number of Rock Lake lakefront owners who own wake boats has increased over the last few years. A rough estimate of wake boats is 30.  According to a survey done by the Jefferson Land & Water Conservation Department in 2021, there were 448 lifts on Rock Lake. Assuming that all lifts represent boats, roughly, wake boats represent 6.6% of riparian boats (30/448).

In response to concerns, the industry launched a “Wake Responsibly” campaign in March 2022.  The campaign consists of three pillars: 1) Stay at least 200 feet away from the shoreline, docks, or other structures allowing boat wakes to recede enough to minimize any adverse effects. 2) Keep Music at a reasonable level, and 3) Minimize repetitive passes on any one portion of shoreline. Repetitively surfing back and forth in the same line can damage shores and docks.

The first pillar is based on two studies: Characterization of Wake-Sport Wakes and Their Potential Impact on Shorelines, Goudy et al. – 2015; and Numerical Study of the Impact of Wake Surfing on Inland Bodies of Water (2022)  In the Goudy study, the Water Sports Industry Association (WSIA) paid ocean engineering firm C. A. Goudy and Associates, to do the study, but the WSIA didn’t have Goudy analyze their own data or make any recommendations. WSIA confirmed that they did the analysis, however, there is no record of who at the WSIA did the analysis, how they did it, and how 200 feet from the shoreline, docks or other structures was chosen.
-Here is a link to a critique of the study: Microsoft Word – 5.26.2024.Review.WSIA-Goudey.Wakesurfing.StudyCopy (squarespace.com).

The second study funded by Mercury Marine, a manufacturer of wake boat engines, used computer modeling rather than capturing data during actual boat passes as in the University of Minnesota St. Anthony Falls study.
-Here is a link to a critique of the study: Microsoft Word – 5.25.2024.NMMA-Fay.Full.Critique (squarespace.com)

An interesting aspect of the industry’s research is the claim that waves generated by the wind have a greater impact than enhanced waves created by wake boats 200 feet from shore. According to testimony by C. Phillips to Wisconsin’s Natural Resource Board (NRB), Goudy’s research indicated that enhanced waves created by wake boats 200 feet from shore were over 16 inches tall. In his research, Goudy added up four minutes of small waves (about 180 waves, each 3-4 inches high) from a 10-mph breeze across a mile fetch (about the width of Rock Lake east to west), and determined that they had the same potential for damage as a 16 inch wave. “If your common sense is telling you something is wrong,” Phillips testified, “you’re right. It’s like saying getting hit with a bunch of marshmallows is the same as being hit with one baseball.”

Using Goudy’s calculations, Rock Lake would need at least 15 minutes of sustained 45 mph winds, from the west or southwest, to generate 16 inch waves on Bartel’s Beach. Such winds would be extremely rare if ever. In the last two years no sustained winds over 45 mph occurred at any of Wisconsin’s five busiest commercial airports.

Lastly, the industry has completely ignored the concerns of being unable to completely drain ballast tanks. Consequently, ballast water and invasive species are transported between lakes. In order to comply with existing Wisconsin state law, the industry would need to re-design new boats and recall existing boats to retrofit the tanks.

Here’s a video advertising Mastercraft wake boats.  Admittedly, the video is thrilling, however, it treats the lake like a water park for that recreational user.  What about others and the lake inhabitants? (Note: These wakes are larger than 16 inches)  https://youtu.be/b9RtJvvuwiM

As of this month, 25 towns/municipalities have ordinances regulating the creation of enhanced wakes on 120 Wisconsin lakes.  To help you identify where these lakes and towns are located, this map highlights the counties where they reside.  In Wisconsin, counties can NOT regulate lakes, just rivers. For Rock Lake, the Town of Lake Mills is the regulating body.

In April 2024 another unit of government, The Lac du Flambeau Band of Lake Superior Chippewa Indians, prohibited wake-enhanced boating on the 260 lakes within the boundaries of their reservation which cover parts of Vilas, Oneida, and Iron counties, including the Tribe’s largest lake– 3,483-acre Fence Lake in Vilas County.

The first ordinance regulating enhanced wakes was enacted in 2009 along a section of the Milwaukee River.  Lately, the majority of ordinances are modeled after the 2021 ordinance regulating Crystal Lake in Sheboygan County.  In this ordinance, a specific type of boat is not banned, just the activity of creating enhanced wakes through ballast tanks/water sacks/fins/or continuous operation at transition speed. Recreational users can still water ski, tow a tube, and transition operate their boat while accelerating to a planing speed, or to empty their boat of water. Some towns have also regulated distance from shore and/or depth of operation. Two lakes have experimented with voluntary guidelines including Ashippun Lake (Waukesha County) and Green Lake (Green Lake County).  Ashippun Lake requests enhanced wakes to be created 500 feet from, and parallel to a specific shoreline. Green Lake asks that enhanced wakes be created 700 feet from shore and in water 40 feet deep.

The DNR reviews and enforces state and local ordinances – it does not define them. The DNR is supportive, however, of the Crystal Lake ordinance and encourages other groups to use it as a model.  In fact, this is the ordinance that the Town of Oakland used to draft their ordinance regulating Lake Ripley. It’s interesting to note, that although many towns have been threatened with lawsuits challenging their ordinances, none have actually been sued. A complete listing of ordinances can be found on this webpage.

Note: Residents often wonder whether incoming boats can be treated differently than riparian boats already on the lake. Wisconsin’s Public Trust doctrine firmly states that the “navigable waters of the state are public and held in trust by the state to protect the public’s rights to those waters.” Consequently, no units of government have issued regulations that treat riparian boaters differently than other public boaters.

During the last legislative session, two bills were introduced regulating enhanced wakes. The first bill was sponsored by Sen Mary Felzkowski (Tomahawk) and Rep Rob Swearingen (Rhinelander) and mirrors industry sponsored legislation offered in other states: operation 200 feet from shore, not allowed in lakes smaller than 50 acres (current Wisconsin law prohibits motorized boats on lakes smaller than 50 acres), prohibits more restrictive local ordinances, and a request to be courteous to other boaters, and to maintain a safe distance from other boats, swimmers, and structures. The other bill was sponsored by Sen Andre Jacques (De Pere) and Rep Christine Sinicki (Cudahy, St. Francis, southern Milwaukee): operation 700 feet from shore, in water at least 20 feet deep, and on lakes at least 1,500 acres in size. Neither bill made it out of committee or received a hearing.

In its spring survey, the Wisconsin Conservation Congress asked if the public would support legislation prohibiting intentionally magnified wakes on lakes smaller than 1,500 acres, in depths less than 20 feet, and at distances less than 700 feet from shore. Of the 10,895 Wisconsin residents who offered an opinion, 69% said “yes”, they would support those restrictions. The question passed in all 72 counties.  The vote is non-binding, however, it could be influential with lawmakers.

Two county boards in northern Wisconsin (Vilas and Oneida) passed non-binding resolutions asking legislators to adopt statewide standards on wake boat regulation. Their resolution framework was to limit enhanced wake operation at least 500 feet from shore, and in water at least 20 feet deep.

 Anticipating continued legislative action, a coalition of conservation-minded, non-profit organizations are drafting a legislative platform for state-wide regulation.  This coalition includes: Wisconsin Wildlife Federation, Wisconsin Greenfire, Walleyes for Tomorrow, Wisconsin Lakes, Wisconsin Land and Water, Last Wilderness Alliance and Lakes at Stake. At the May 2024 meeting of the Wisconsin National Resources Board (NRB), a spokesperson for the coalition stated that they have been working to reduce and manage the impact of wake-enhanced boating on Wisconsin’s lakes and other waters through “reasonable, science-based education and, where appropriate, regulation.”

Interested in discussing this issue with others?  Join us for a public presentation and a Q&A session by John Richter of Last Wilderness Alliance. The August 17th meeting will be held at Korth Park, Upper Pavilion, at 10am.  You are also invited to stay for the RLIA Annual Membership Meeting which follows. 

In July, RLIA introduced the idea of a Voluntary Wake-Sport Zone to Rock Lake riparians and members. This zone was carefully crafted to keep enhanced-wake recreation in the deepest part of Rock Lake.  The 600-foot buffer helps dissipate waves before they hit the popular fishing ledge just east of the zone located at a depth of 25 feet.  The buffer also allows riparians along Shorewood Hills Rd to access the lake safely since waves would dissipate to be similar to wakes from a typical powerboat 100 feet away.  The buffer also enables other boaters to safely circumvent the wake zone. With the buffer, about 17% of Rock Lake’s unrestricted surface will be devoted to enhanced-wake recreation.

The actual zone encompasses about 41 acres which would offer: one large loop (3000ft x 600ft) of about 7 minutes; or two straight runs, 3000ft for about 3 mins each way (11 mph is about 1,000 ft/min).  

Finding the zone is easy. The Jefferson County Land and Water Conservation Department created an interactive map based on Google Maps.  By clicking this link with your phone, you will see the red rectangle of the zone and then see your boat as a blue dot. https://www.google.com/maps/d/edit?mid=1fo-GEu_MzR0cg_5QrEECUmolBQGTp9Y&usp=sharing  Save it on Google Maps so that you can always find it.  Visually, the zone stretches from the 3rd/4th northern Korth Bay Slow-No-Wake buoy and angles towards the north end of Tyranena Park. 

We also urge wake boat operators who call Rock Lake home to not take their boat to other waters.  If that happens, you’ll leave Rock Lake water there, and bring back some hitchhikers. Lake Michigan, all the Madison lakes, Lake Winnebago and seven other lakes in northern Wisconsin all have the spiny water flea.  A number of southeastern lakes such as Okauchee, Pewaukee, Nemahbin, Geneva, and Little & Big Muskego Lake have starry stonewort, another invasive which would cause considerable problems for Rock Lake.

Interested in discussing this issue with others?  Join us for a public presentation and a Q&A session by John Richter of Last Wilderness Alliance. The August 17th meeting will be held at Korth Park, Upper Pavilion, at 10am.  You are also invited to stay for the RLIA Annual Membership Meeting which follows.