What is a wake boat?
Minnesota has over 800,000 registered boats plying the waters of more than 11,000 lakes, providing countless hours of enjoyment for boaters. While many boaters operate their boats safely, some are careless when it comes to public safety and protecting the environment. One type of vessel, the wake boat, is exceptionally destructive if operated without care. Tanks at the back of these boats take on thousands of pounds of lake water to increase their weight, a design that causes them to ride bow-up and stern-down. Coupled with powerful motors pointing their propeller at a downward angle, the boats produce strong high-energy wakes and propwash. This allows people to surf untethered behind them.
What is the environmental impact of wake boats?
Just one pass of a wake boat can be devastating to an ecosystem. Multiple passes in the same area cause long-lasting damage to shorelines, water quality, and lake bottoms.
Wake boats erode vulnerable shorelines when the distance to shore is not adequate to dissipate the wakes. The wakes can also damage docks, swamp other boats, endanger swimmers, and destroy waterfowl nesting sites.
The downward angle of the propwash from wake boats causes algae blooms by stirring up sediment and reintroducing sequestered phosphorus and nitrates into the water column. Lake water is warmed by this increased turbidity, making aquatic ecosystems less hospitable for native flora and fauna. Often native plants are uprooted and fish nests destroyed.
Aquatic Invasive Species (AIS) are pumped into the ballast tanks along with lake water. These tanks are difficult to clean and end up spreading AIS to other waterbodies. Until the boating industry improves the tank-cleaning process, wake boats will continue spreading AIS.
What do studies show?
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A 2015 non-peer-reviewed commissioned report by the Water Sports Industry Association (WSIA) argues that wake boats only cause problems if they are closer than 200 feet to shore. The study makes no mention of required water depth.
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2014-15 scientific studies from the University of Quebec, Montreal and Université Laval show that boats need to maintain at least 1,000 feet (300 meters) from shore to prevent most erosion and operate in at least 15 feet of water (5 meters) to prevent sediment re-suspension.
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A 2022 peer-reviewed study of wave dynamics by the University of Minnesota’s St. Anthony Falls Lab (SAFL) found “…wakesurf boats produced maximum wave heights that were ~2-3 time[s] larger, total wave energies that were ~6-9 times larger, and maximum wave powers that were ~6 to 12 times larger than the non-wakesurf boats.”
The SAFL study goes on to state that “…operational distances greater than 500 feet are required for the wake waves generated by a wakesurf boat to attenuate to similar wake wave characteristics as the non-wakesurf boat reference.”
This means that the current recommendation of 200 feet from shore, as stated in the “Own Your Wake” initiative from the Minnesota Department of Natural Resources (MNDNR) and the “Wake Responsibly” campaign by the WSIA, are not aligned with the SAFL study results.
The next phases of the SAFL study will measure the impact wake boats have on shorelines, water columns, and lake bottoms.
What are governing bodies doing about this problem?
State legislatures across the country, from New Hampshire to Washington, are struggling to weigh the impact of wake boats on the environment, public safety, and the economy. Many have done their own studies and have enacted various laws and regulations suited to their area’s particular needs. Last summer the Lake Minnetonka Conservation District compromised by creating a rule by which all watercraft must not exceed a 5-mile-per-hour speed within 300 feet of shore. There are currently no bills in the Minnesota Legislature about protecting our aquatic ecosystems from powerful boat wakes and prop wash.
What should we do about this issue?
Each waterbody has unique characteristics regarding water quality, shoreline vulnerability, lake bottom types, sequestered contaminates, animal habitat, accessibility, and historical use. No singular statewide regulation for distance offshore or water depth will adequately protect all our lakes and rivers from the destructiveness of wake boats operated improperly. Some shorelines are naturally hardened and able to withstand wake boats operating nearby. Other shorelines may be so sensitive that 1,000 feet may not be enough to protect them. Some lakes have lots of contaminants sequestered or are too shallow to allow wake boats at all. Some lakes are deep with rocky bottoms where prop wash will have little effect. The solution is elusive.
Consequently, waterbodies having characteristics that can withstand the operation of wake boats need to be identified. These characteristics must be determined by sound peer-reviewed scientific studies, such as SAFL’s upcoming research. Designating waterbodies as “wake boat safe” will not only protect the environment, but also help wake boaters know where they can operate without fear of damaging aquatic ecosystems.
Waiting for future studies and waterbody designations will not protect our lakes and rivers now. We encourage the MNDNR, WSIA, and other organizations to immediately update their current recommendation for wake boaters to stay at least 500 feet from shore and operate in water depths of 15 feet or more.
What can you do?
It is certainly challenging to find a balance between competing demands on our waterways.
The Sierra Club is advocating for legislators to:
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Fund independent scientific peer-reviewed studies regarding this issue (See bills HF172 and SF442, both line 9.3).
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Introduce and pass a bill that requires boats producing large wakes to stay at least 500 feet from shore and other objects. Also require them to operate in depths greater than 15 feet. This would be a temporary measure until more specific legislation can be passed.
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Introduce, pass, and implement another bill giving the MNDNR authority and responsibility to evaluate and designate waterbodies or portions of waterbodies as “wake boat safe.”
Join us in contacting your legislator. Personal calls are one of the most effective ways to get involved, so find out who represents you and then give them a call!
Let’s protect our 10,000 lakes so that future generations can continue to enjoy countless hours on the water.
By the Wake Boat Subcommittee of the Waters and Wetlands Stewards, North Star Chapter of the Sierra Club