New Wakeboat Research Out – and it isn’t good for Wisconsin Lakes

Wisconsin Based Terra Vigilis just completed their on-the-water research project at Lake Waramaug, a 656 acre lake, located in western Connecticut.

The report is now public on the Town of Warren website and provides for fascinating reading. A direct link to the report is HERE.

At the request of local officials, Terra Vigilis was tasked with measuring the impacts of both divergent waves and downward propwash of wake surf boats as compared to typical runabouts such as a Cobalt.

One of the key findings was:

“To dissipate the Wake Board Boat in Surf Mode wave to the same height and energy as a Ski Boat at 100 ft requires increasing the distance from shore to over 500 feet. This corresponds with results from other studies….”

These findings once again indicate that you are not imagining things. The waves from wakeboats are more powerful than traditional watercraft historically used on Wisconsin Lakes.

The groundbreaking element of the Lake Waramaug study related to the impact of downward prop wash from a wakeboat in wake surf mode. There has been scant research done on this topic to date due to the fact research has been focused on surface wave action.

For the downward propwash study, Terra Vigilis placed a rod array in the water column, anchored by a concrete block on the lake bottom at a depth of 26 feet. (see diagram below courtesy of the Terra Vigilis report)

Lakebed Impacts at 26 feet

Cameras and streamers were placed at five foot intervals, with the goal of determining if wake surf prop wash could be detected and at what depths.

Per Section 4.2 of the report:

“Propeller downwash depths were measured under repeated startup and buoy pass testing conditions and reveal deep fluid kinetic energy activity for wake board boats in surf mode compared to minimal impacts by a water ski boat under identical testing conditions. Subsurface imagery as depicted in Figure 10 reveals propeller downwash impacts occurring at depths of at least 26 feet for a wake board boat in surf mode”

The new data changes the calculus both locally and nationwide. As many recall, Vermont enacted regulations earlier this year which allow wakesurfing to occur only on thirty lakes that satisfied certain depth, distance, and operating area requirements. The minimum depth requirement utilized by the State for these thirty lakes was 20 feet. The thirty remaining lakes are able to petition to prohibit wake sports, and many are in the process of doing so.

As a result of the new Terra Vigilis prop wash data, the ten bigger, deeper Vermont lakes that have each submitted their individual petitions to the Agency of Natural Resources (ANR) to prohibit wakesports can request that the state’s regulatory depth requirement for wakesurfing be increased from a minimum depth of 20 feet to a minimum of 30 feet to ensure the lake bottoms are adequately protected.

Phosphorous Levels Increased

The final major discovery in the research relates to phosphorous disruption.

“Of additional interest, total Phosphorus sampling at these deep sites (sampled at 20 feet), also reveal a 110% increase in Total phosphorus levels released immediately following startup impact measures for wake board boats in surf mode. By comparison, no significant increase in measured Total phosphorous levels was found for water ski boats in startup conditions. (The reader is cautioned that this finding is preliminary in nature, was not the primary focus of the project, and warrants additional study.)”

We’re certain the wakeboat manufacturers and their lobbying groups will be racing to try and discredit this study. However, the scientific evidence continues to pile up in favor of common sense reforms for wakeboat use on Wisconsin Lakes and Rivers.

Coalition for Reform Update

Lakes at Stake Wisconsin is a founding member of what is now a fast growing coalition of groups seeking common sense minimum protections for Wisconsin Lakes and Rivers. The wakeboat manufacturers are learning that Wisconsinites aren’t going to roll over and allow our lakes to be irreparably damaged from wakeboats.

We’re now up to 54 Wisconsin based organizations, representing many different interests across our State. More importantly, these groups represent hundreds of thousands of Wisconsin voters. And this is a bipartisan movement, with strong support from both Republicans and Democrats.

Joining the coalition is free and your only obligation is to lend your support (and a logo) to our growing movement. The more groups we have, the more powerful our voice in Madison will be. To join the Coalition, one only needs to agree with our policy statement. Please click this link to learn more!

And to join the Coalition, reach out to [email protected] for more information.

Financial Support for the Fight in Madison

We’re getting word that the wakeboat manufacturers continue their heavy lobbying efforts in Madison to defeat any potential reform legislation. Further, there is a belief that they are trying to once again promote a bill that would provide no meaningful protections while stripping away the right of municipalities to enact local ordinances that are protective of their lakes.

The good news is that Lakes at Stake Wisconsin is working in your interests via our professional lobbyists at SJL Government Affairs and Communications.

Stay tuned for future updates as things heat up come January. We are going to need your continued financial support in these efforts!

Downward Propwash and lakebed damage

We have some new updates related to our downward prop wash video. As noted in a prior newsletter, we have discovered the same bottom craters in Big Cedar Lake in Washington County, as were found in Pewaukee Lake, and highlighted in our video.

A thin layer of clean ice allowed for some drone footage of these craters last week. As you can see from the photo below, there are a series of craters that resemble sand traps on a golf course. These craters are on the edge of a dropoff in 6-15 feet of water. They were not present in drone photography of the same area in 2023.

The size and shape of these craters is consistent with a working theory that they are created when a wakeboat starts up with a new wake surf rider. The crater shapes are symmetrical and there are clean margins on the edges of the craters as it relates to the absence of any aquatic vegetation.

The new Terra Vigilis research represents the beginning of the journey to understand the subsurface impacts of wakesurfing. Lakes at Stake is committed to doing our own independent underwater research on these craters. We are seeking certified scuba divers to assist in research on southeastern Wisconsin Lakes. If you would like to help us with this research, please reach out to us at [email protected]

Bottom craters as seen on a Hummingbird Solix side scan sonar