Lake aeration has the potential to prevent winterkill of fish, improve water quality, or protect structures from ice damage. Aeration can also be a public safety hazard in the winter due to creation of open water areas normally frozen over. A permit from the DNR is required to operate an aeration system on public waters in Minnesota.
Aeration permits
A permit is required to operate and install an aeration system during periods of ice cover on public waters in Minnesota.
New permittees and new operators: Are required to complete a workshop as a condition of receiving an aeration permit. Viewing the Aeration Safety Video and complete the safety training quiz will satisfy this requirement. Anyone actively involved in the operation of your aeration system should also review the Aeration Safety Video.
Existing permittees and existing operators: Are encouraged to review the Aeration Safety Video annually.
All permittees and/or operators are required to complete the Operator Safety Quiz every three (3) years.
Apply for or renew an aeration permit
To apply for a new permit or renew an existing aeration permit, please use the MNDNR Permitting and Reporting System. If you are using MPARS for the first time, you will need to create an account. Once created, click on the link in the Actions box called "Apply for a New Permit/Authorization."
MPARS is the easiest and most convenient method for most people to apply for a new or renew an existing aeration permit. If it is not possible for you to apply online, paper application forms may be requested by contacting water permitting and reporting staff at 651-259-5724. Please note that the use of paper forms may not offer the efficiency or speed of the MPARS online process and may result in the need for more follow-up with DNR staff to obtain needed information.
- Review aeration rules and background
-
Get to know the rules
It is important to understand the rules before you make the decision to apply for an aeration permit. Aeration rules and regulations are outlined in Minnesota Rules Chapter 6116 and Minnesota Statutes 103G.611.
Review questions before applying for a permit
- Are you comfortable creating a public safety hazard for lake users?
- Are you comfortable assuming all liability for any safety incidents that occur from your aeration system?
- Have you talked with DNR staff to determine if this would be a good fit for your lake?
- Are your neighbors and other lake residents okay with aeration?
Make an aeration plan
- What type of system do you plan to use and do you have the materials to set it up?
- Where will your system and power source be located?
- Who will be responsible for the operation, finances, maintenance, inspection and repair of your aeration system?
- Who will construct and maintain signs?
- What is your plan if something goes wrong?
- Have you spoken to your neighbors or other lake residents about aeration?
Aeration System Recommendations
Keep the following tips in mind when looking for a system:
- Avoid using hydraulic jets in shallow water.
- Bubbler systems, or pumps/compressors attached to air lines or diffusers, are best for shoreline protections.
- They create a relatively small and narrow open water area.
- The open water area can be easily controlled.
- They system is low impact - does not create a current, displace vegetation, or disturb sediment.
- High horsepower motors are not needed to power the system effectively.
- Fans, blowers, and sump pumps are NOT recommended because:
- They create large open water areas.
- Larger open water areas are more likely to grow quickly, especially on warm, windy days. This creates a more significant safety hazard.
- They create strong currents that have the potential to disturb plants and sediment.
- They are often much more powerful than necessary.
- Complete safety checks
-
Complete weekly safety inspections
- You must inspect your system at least once every seven days. If you're unable to inspect your system, designate someone in your place.
- Download and complete the Lake Aeration Inspection Form.
- On warm and windy days, check the open water area often.
- Keep your own safety in mind. Ice is never 100% safe.
Check with neighbors
- Check with neighbors to see if they have any concerns.
- Watch that your open water area is not growing quickly.
Aerated lakes map
How does aeration work?
Aeration to prevent fish winterkill
Low oxygen levels in some lakes can cause fish to die during some winters. This is known as winterkill.
Aeration systems agitate and mix water in the lake. Warmer water near the bottom of the lake rises to the surface and melts an area of the ice. Oxygen from the air can then be incorporated into the water, and light can also penetrate further into the water, helping with photosynthesis and increasing oxygen. . If low oxygen levels are a problem, aeration might be able to help.
Resources
Aeration for water quality improvement
Summer aeration is often marketed as a tool to improve water quality in lakes and ponds. Aeration systems may improve water quality by moving oxygen to deeper water. This may slow the release of nutrients from lake sediment, which can help decrease algae growth. It is a complex process. Aeration may not improve water quality in your lake or pond, will not permanently solve any water quality issues, and may worsen conditions. Since a lake or pond's character is often a reflection of its geology and the quality of water that flows into it from its watershed, a better solution is a watershed approach to water quality improvement. Talk to your Watershed District or Soil and Water Conservation District for more information. Anybody considering aeration for water quality reasons should consult with a water quality professional. Using the wrong type or size of aeration equipment, problems with equipment operation, inappropriate application of aeration may all result in unsatisfactory results or even degrade existing water quality.
Resources
- Harmful Algal Blooms
- Lake Protection and Management
- Watershed Health Assessment Framework
- Minnesota Water Stories
- A Watershed Approach to Water Quality
Aeration for shoreline protection
When ice expands, frozen sheets of ice may heave or push towards land. This can cause damage to structures near the shoreline. An aeration system creates a thin ice area that accommodates ice expansion. Each lake and shoreline is unique. Aeration for shoreline protection is not guaranteed to be successful. A better solution is to strengthen your shore by avoiding highly manicured lawns, and instead plant native grasses and shrubs. A more natural area near the shoreline will benefit fish and wildlife and be more resilient to minor changes caused by ice forces. A natural ice ridge built up on your shore to protect your shoreline could be the best feature in the near shore landscape.
Before cutting vegetation or disturbing land or building structures near water, please talk to your local zoning authority about regulations regarding vegetation removal and shoreland ordinance requirements.
Resources
Questions
Fish stocking or fish kills
Contact your Area Fisheries Office
Shoreline protection or shoreline restoration
Contact your Area Hydrologist
Violations or report a violation
Contact your Conservation Officer
Aeration questions-
Contact Water Regulations Unit Aeration Program Coordinator Denise Elston, with general aeration-related questions at 218-580-8646. For fisheries, water quality or winterkill related aeration questions, please contact your local fisheries office.