How powerboats impact lakes below the surface
July 29, 2025
Large surface waves produced by powerboats are a mainstay for recreational watersports. A new study from the University of Minnesota shows that beneath the surface, factors such as propeller thrust and other types of waves can impact delicate lakebed ecosystems.
Researchers at the University’s St. Anthony Falls Laboratory built on previous research to study the effects of powerboats on lake ecosystems over the 2022 and 2023 field seasons. The team placed acoustic-based sensors that measured pressure and velocities through the water column and at the lake bottom at two different locations and at two different depths. They also collected sediment samples and data on various water quality parameters.
The study was supported by a University crowdfunding campaign with over 200 donors. Additional funding was provided by the Environmental Natural Resources Trust Fund (ENRTF) as recommended by the Legislative-Citizen Commission on Minnesota Resources (LCCMR).
The researchers tested seven recreational powerboats commonly used in Minnesota’s lakes and rivers based on their two most-used settings. For non-wakeboats: displacement mode/leisure cruise and planing mode/cruising. For wakeboats: semi-displacement mode/surfing and cruising. The boats were driven directly over the measurement sensors five times for each operational condition.
Credit: St. Anthony Falls Laboratory, University of Minnesota.
The study, published in the University Digital Conservancy, found:
- All powerboats produce water currents and turbulence that can disturb the lakebed.
- More powerful turbulence from wakeboats can directly resuspend sediments in the water. This can indirectly lead to release of nutrients like phosphorus from sediment that can stimulate excessive algae growth, which adversely impacts lakes.
- All powerboats, when leisurely cruising or planing, should operate in 10 feet of water or greater to minimize impacts caused by motions generated by a boat’s hull.
- During surfing, wakeboats should operate in depths of 20 feet or greater to minimize negative impacts on the lake environment.
“For all motorized boats, simply being careful about where you steer your boat and avoiding shallow spots can make a huge difference,” said Jeff Marr, co-author on the study and associate director of engineering and facilities at the St. Anthony Falls Lab in the College of Science and Engineering. “Staying in deep water when you’re out on the water — especially when wakeboarding or surfing — is an easy and effective way to enjoy and protect our waterways. Also, give space between your boat and other boaters and the shoreline.”
Fieldwork for the final phase of the research will conclude in fall 2025. This project phase will examine how wind-driven waves differ from wake waves produced by recreational boats, including their impacts on the lake environment.
Research partners from the St. Anthony Falls Lab include Andrew Riesgraf, William Herb, Matthew Lueker and Jessica Kozarek.
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About the St. Anthony Falls Laboratory
Established in 1938, the St. Anthony Falls Laboratory is an interdisciplinary fluid mechanics research lab and educational facility under the College of Science and Engineering at the University of Minnesota. The lab’s engineers and scientists collaborate across disciplines to solve fluids-related problems. The lab’s vision encompasses both science and practice, beginning with basic research and moving through application, decision-making, and management. To learn more, visit safl.umn.edu.
New Boater Education Law
Effective Date: July 1, 2025
Starting on July 1, 2025, a new law requires some adults and youth who operate motorboats—including personal watercraft—to have a valid watercraft operator’s permit (commonly also known as a boater safety certificate). People who already have a watercraft operator’s permit are not affected by the law, which is designed to make boating safer by ensuring everyone operating a motorized watercraft knows the rules and is properly trained. Here’s a breakdown of the key points:
Adult operators:
- Permit requirement: Some adults (defined below) need a valid operator’s permit to drive any motorboat or personal watercraft starting July 1, 2025.
- Exemptions: Some adults are exempt from this requirement. Check the law for specific exemptions.
- Supervised operation: People without a permit still can operate a boat, but only if there’s an accompanying operator (defined below) onboard.
Young operators:
- Restrictions on high-powered watercraft: Young operators (people less than 12 years old), can’t operate a personal watercraft or any motorboat with a motor over 75 horsepower.
- Low-powered motorboats: Young operators can operate a motorboat that’s not a personal watercraft and has a motor under 75 horsepower as long as there is an accompanying operator in the motorboat.
Who is considered an adult operator?
- Is 12 years old or older, and
- Was born after these dates:
- June 30, 2004 (started July 1, 2025)
- June 30, 2000 (starts July 1, 2026)
- June 30, 1996 (starts July 1, 2027)
- June 30, 1987 (starts July 1, 2028)
This means people born after June 30, 2004, will need a permit to operate a boat starting in 2025. The permit requirement will gradually apply to older age groups over the next few years.
Who is considered an accompanying operator?
- A person 21 years of age or older who:
- Is in a personal watercraft or other type of motorboat;
- Is within immediate reach of the controls of the motor; and
- Possesses a valid operator’s permit or is an exempt operator.
Who is considered an exempt operator?
“Exempt operator” means a motorboat operator, including a personal watercraft operator, who is 12 years of age or older and who:
- Possesses a valid license to operate a motorboat issued for maritime personnel by the United States Coast Guard under Code of Federal Regulations, title 46, part 10, or a marine certificate issued by the Canadian government.
- Is not a resident of the state, is temporarily using the waters of the state for a period not to exceed 60 days, and:
- meets any applicable requirements of the state or country of residency; or
- possesses a Canadian pleasure craft operator’s card;
- is operating a motorboat under a dealer’s license according to section 86B.405; or
- is operating a motorboat during an emergency.
Key takeaways:
- Adult and youth permits: Young operators and some adults need a valid watercraft operator’s permit to operate certain motorized watercraft. For adults born after June 30, 2004, the requirement started July 1, 2025. The law will extend to older age groups over time.
- Youth restrictions: Young operators can’t operate boats with more than 75 horsepower. They can operate boats (that are not PWC) with less than 75 horsepower if they’re with an accompanying operator.
- Gradual rollout: The law will phase in over the next few years. The operator permit requirement started July 1, 2025 and gradually expands through 2028.
This new law aims to improve safety on the water by making sure everyone operating a motorized watercraft is trained and qualified.
Rentals:
- 18 and older:
- If renting from a rental business and from Minnesota: Must be an exempt operator; complete the Minnesota watercraft rental course (certification is good for 180 days); or already have or obtain a watercraft operator’s permit (certification is good for a lifetime).
- If renting from a rental business, not from Minnesota, and using Minnesota’s waterways for fewer than 60 days: Must meet any applicable requirements of state or country of residency.
- If renting from a resort and from Minnesota: Must meet watercraft operator permit age requirements. (Those born after June 30, 2004, must hold a valid watercraft operator’s permit.)
- If renting from a resort, not from Minnesota, and using Minnesota’s waterways for fewer than 60 days: Must meet any applicable requirements of state or country of residency.
- Under 18:
- Cannot rent watercraft, but Minnesota residents may operate rental watercraft if they have a valid watercraft operator’s permit. Non-residents under 18 also cannot rent watercraft but may operate rental watercraft if they’re using Minnesota’s waterways for fewer than 60 days and meet any applicable requirements of state or country of residency. (Please note: Rental businesses and resorts may also have their own requirements that are more stringent than state law.)
Low-powered motorboats
This new law does not affect individuals who operate motorboats powered by a motor with a factory rating of 25 horsepower or less. People of any age do not need a valid watercraft operator’s permit or have an accompanying operator in the motorboat so long as it is not a personal watercraft and is powered by a motor with a factory rating of 25 horsepower or less.
SIGN UP NOW to take the watercraft operator’s permit course: https://www.dnr.state.mn.us/safety/boatwater/education.html.
AIS Information
The Wabana AIS boat decontamination unit is available at the Wabana Town hall – 30980 Clearwater Rd, Grand Rapids, MN 55744
The decontamination unit will be staffed Friday, Saturday and Sunday from 9:00 AM – 7:00 PM
Hot water decontamination is free to everyone during the hours the unit is staffed
PLEASE utilize this resource to help keep our lakes from being contaminated with aquatic invasive species (AIS)
WCOLA AIS Information for Resort Owners
A reminder to use Five Star Providers.
Itasca Five Star Lake Service Providers
Aquatic Invasive Species (AIS) have become a very real threat to our way of life in the Northland. The Itasca County AIS Program was created to meet these threats. We all must do our part to help stop the spread of AIS. Everyone needs to take personal responsibility for not spreading AIS.
The Itasca AIS Program and participating area lake associations (including WCOLA) are implementing an initiative intended to promote Lake Service Providers to lake and river shoreline property owners and to prevent AIS from being transported from one body of water to another. This is called the FiveStar Lake Service Provider initiative.
List of FiveStar Lake Service Providers: http://bit.ly/FiveStarLSPs
Itasca FiveStar Lake Service Providers are those who agree to implement the following AIS safeguards in addition to earning and maintaining Minnesota DNR Permitted status:
- I agree to monitor closely the official DNR list of infested waters so I am always up to date on which waters are infested. http://www.dnr.state.mn.us/invasives/ais/infested.html
- I agree that any equipment I use in AIS infested lakes will before its use in any other lake always undergo thorough thermal decontamination to DNR spec, performed myself, performed by a DNR certified AIS technician on my staff, or via an AIS thermal decontamination unit operated by the Itasca AIS program (218-256-4243).
- I agree to certify that any used dock, lift, swim-raft, anchor, ladder, buoy, or any similar water-related equipment I sell or am asked to move from one water body to another has been out of the water and dried out for at least 21 days AND undergone a thorough thermal decontamination performed by the Itasca County AIS program (218-256-4243) or other DNR-certified AIS technician. Decontamination always includes a non-contact infrared thermometer to verify water temperature. The Itasca County AIS program is happy to provide inspection and decontamination services for free.
- I agree that the Itasca AIS program may from time-to-time visit and review my operations to determine that my firm is abiding by this Agreement and offer recommendations for improvement.
- The Itasca AIS program offers to pay the initial registration fee for any lake service provider who achieves MN DNR Permitted status. In addition, the Itasca AIS program offers to pay the ongoing registration fee to maintain MN DNR Permitted-status for all Itasca FiveStar lake service providers.
Here is an interesting Newsletter on Invasive Species
Zebra Mussel Alert
The first new Zebra mussel infestation in 4 years was confirmed this week at North Star Lake.
Area residents and lodges have responded with positive action.
[cid:part1.ACB0B70E.16F2CB64@paulbunyan.net] (photo taken at North Star Lake late September)
WHAT IS BAD ABOUT ZEBRA MUSSELS?
1. They grow and reproduce quickly. Zebra Mussels reproduce high numbers of eggs in their second season of life. A single female mussel can produce up to one million eggs a year.
As the mussel population explodes, they cover the bottom and sides of almost everything.
2. They can change native plant and animal communities. The amounts of food they eat and the waste they produce have
As filter feeders, they remove large amounts of microscopic plants and animals that form the base of the food chain, reducing available food for native aquatic species.
Zebra mussels attach to and encrust native mussels, essentially smothering them and removing more animals from the food chain.
3. They have recreational impacts. Zebra mussels encrust docks and boats. Small mussels can get into engine cooling systems, causing overheating and damage.
Zebra mussels also impact fish populations and reduce sport fishing opportunities. Their sharp shells can cut the feet of swimmers,
4. They cost us money. They clog water intake pipes disrupting water supplies. Zebra mussels also degrade water quality and can alter the smell and taste of the water.
Property values on infested lakes can also be adversely affected.
WHAT EVERYONE ON The Wabana Chain of Lakes CAN DO NOW:
Get outside now and check your docks, lifts and swim platforms for anything unusual. If you haven’t pulled them from the lake yet, wade out and check things out.
Go out in a couple of feet of water. Pick up and examine sticks, rocks, clams… anything. Do you see anything unusual?
We all need to know what our lakeshore and lake bottoms in front of our properties look like. The only way we can remove any AIS from our lakes is if we catch it early before it has become
This Early Detection is only possible if YOU keep an eye on YOUR property, equipment and lake bottom in front of your property.
Call Bill Grantges Itasca AIS Coordinator at 218-256-4243 if you find anything that does not belong,
if you have any questions or if you would like us to
or the DNR AIS Specialist Rich Rezenka at 218-328-8821
For more information see the following: Itasca County Aquatic Invasive Species Videos
<https://www.youtube.com/channel/UCmKAaGPf_mGPY68q2OKRycQ> Zebra Mussels on Sand Lake<https://www.youtube.com/watch?v=B1Xo7UcBB8s>
We all need to work together to Preserve Our Outdoor Traditions!
Moving Docks, Boat Lifts, and other Equipment Residents may not be aware of the Minnesota law which states “a boat lift, dock, swim raft, or associated equipment that has been removed
from any water body may not be placed in another water body until a minimum of 21 days
After a thorough cleaning, equipment should be kept dry for a minimum of 21 days before placing in the water. DNR Permit required for transporting docks, lifts
and/or move a dock, boat lift, swim raft, or other water equipment from one lake or river to another, all visible zebra mussels, faucet snails, and aquatic plants must be removed whether they are dead or alive.
A DNR transport authorization permit form is required for individuals who are moving equipment which has had prohibited invasive species and/or plants attached. There is no charge for this permit.
If a business provides this service for you, the business would need to get a lake service permit. These forms are available on the DNR website: http://www.dnr.state.mn.us/permits/invasive_species/index.html
If you hire someone to move your equipment, make sure the provider is on the DNR’s list of Permitted Service Providers, located online
(List is organized by county). To find out if a lake is infested with invasive species, check the DNR Infested Waters List at http://www.dnr.state.mn.us/invasives/ais/infested.html
Source: http://www3.extension.umn.edu/county/itasca/county-natural-resource-educator/article/information-moving-docks-lifts-and-equipment-itasca-county
Here is our approved plan for any infestation: