Lake Aeration Program

bee flying near purple flowers

 

Lake aeration can prevent winterkill of fish, improve water quality, or protect structures from ice damage. Aeration can be a public safety hazard in the winter due to open water in the ice. 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.

Apply for a Permit

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

  1. Are you comfortable creating a public safety hazard for lake users?
  2. Are you comfortable assuming all liability for any safety incidents that occur from your aeration system?
  3. Have you talked with DNR staff to determine if this would be a good fit for your lake?
  4. Are your neighbors and other lake residents okay with aeration?

Make an aeration plan

  1. What type of system do you plan to use and do you have the materials to set it up?
  2. Where will your system and power source be located?
  3. Who will be responsible for the operation, finances, maintenance, inspection and repair of your aeration system?
  4. Who will construct and maintain signs?
  5. What is your plan if something goes wrong?
  6. 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.
Submit an Application

Fill out an application form

Complete the aeration application form and mail or email to:

Minnesota Department of Natural Resources
500 Lafayette Road, Box 25
St. Paul, MN 55155

[email protected]

Review Additional Applications Materials (if needed)

After your application is received, the DNR will contact you with a list of additional application materials:

  • $250 application fee
  • Proof of $500,000 liability insurance
  • Proof that a public notice was published twice between five to 60 days before the start of aeration

Receive your Permit

If approved, you will receive a permit via mail or email. Keep the permit and contact the Aeration Program Coordinator when you turn on your system.

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

These lakes likely have aeration systems in operation during winter.

 

How Does Aeration Work?

Aeration to prevent fish winterkill

Low oxygen levels during the winter can cause fish to die. 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.

Resources

Aeration for water quality improvement

In summer, aeration systems are sometimes used to 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. This is a complex process. Aeration may not improve water quality in your lake and will not permanently solve any water quality issues. 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.

Resources

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 cutting back mowing and planting native grasses and shrubs. If possible, let a natural ice ridge build up on your shore to protect your shoreline.

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
Amanda Yourd, Aeration Program Coordinator / Hydrologist, 651-259-5087