Underwater videos reveal impact of wakesurfing on Minnesota lakes

Wakesurfing underwater impact?

Underwater turbulence from wakesurfing can ?adversely? impact Minnesota?s lakes, according to a highly anticipated study by the University of Minnesota.

MINNEAPOLIS (FOX 9) - Underwater turbulence from wakesurfing can "adversely" impact Minnesota’s lakes, according to a highly anticipated study by the University of Minnesota.

Wake boats and the environment 

What we know:

While the study acknowledges that all boats have the potential to damage aquatic vegetation, researchers recommend that wake boats should only operate in "surfing mode" on lakes where the water depth is 20 feet or greater to minimize impacts on the lakebed.

Researchers with the Saint Anthony Falls Laboratory conducted the multi-year study on Lake Minnetonka, using a variety of powerboats, underwater sensors and cameras. 

"It's significant," said Jeff Marr, the principal investigator of the research. "Boats are getting bigger, more powerful in the state, and so that energy is going into the water and it's impacting the water column and the lakebed."

The study found that turbulence from wake boats can stir up sediments in the water, releasing nutrients like phosphorus, which can lead to excessive algae growth and "adversely impacts lakes." 

Lead researcher Andy Riesgraf said sediments churned up from wakesurfing shallow water "can stay mobilized for a long time." 

Drone video recorded during the experiments reveals the path of disturbed lakebed sediments remained visible for at least an hour after a wakeboat made several passes in "wakesurf" mode.

The study did not evaluate the long-term environmental impacts of boating activity on Minnesota lakes. 

What they're saying:

Advocates for protecting the quality of Minnesota’s lakes told the FOX 9 Investigators the underwater videos offer a striking perspective of the impact of boats on the environment, especially wakeboats at shallow depths. 

"It’s like a bomb goes off – seeing the videos, it just brings it home," said Jeff Forester, executive director of Minnesota Lakes & Rivers Advocates. "I think the results of this study will help protect Minnesota’s lakes." 

However, the boating and water sports industries have pushed back against the findings of the new study. 

"Policymakers should review the full body of science, which supports both environmental stewardship and recreational access for Minnesota families, before making policy decisions based on this study," said Lee Gatts of the Water Sports Industry Association. 

The other side:

The boating industry has its own studies too, including one that says "the environmental impact is minimal" when operating a wakeboat in 10 feet of water 200 feet from shore. However, critics point out that the study is co-authored by employees of boat manufacturer Mercury Marine.

Dig deeper:

The first phase of the study, which was published in 2022, found wake boats need a distance of more than 500 feet to decrease waves similar to that of a standard recreational boat operating at 200 feet. 

The study did not specifically evaluate the effects on the shoreline. 

 Critics say thousands of Minnesota lakes are unfit for wakesurfing 

The backstory:

Wake boats are specially designed to sit deeper in the lake to displace more water and create a bigger, more surfable wave. 

While many of Minnesota’s lakes have rules that regulate wakes, there is no state law that restricts wakesurfing. Efforts to restrict wakesurfing, including distance required from the shoreline, previously failed at the Minnesota Legislature. 

The FOX 9 Investigators recently highlighted the ongoing efforts to restrict wakesurfing across Minnesota’s lakes using local ordinances in the absence of a statewide rule. 

Researcher Jeff Marr hopes their latest study will help inform future conversations about regulating Minnesota’s lakes. 

"I think we really hope, at the highest level, people become aware of what’s going on under the water – what their boat is doing," said Marr. 

What's next:

A third phase to the University of Minnesota study is currently underway. The focus is to examine the effects of waves generated by wind versus powerboats as well as any potential impacts to the shoreline.