Chronology of 2021-2022 Rice Lake Winter Aeration project
November 13, 2021 - Winter Aeration signs posted along shoreline
​In preparation for the winter aeration later this season, signs were posted at various entry points to the lake reminding everyone that winter aeration will be conducted on the lake which will mean there will be areas of open water present. Please use caution when venturing out onto the lake once winter aeration begins.
(Aeration Warning sign locations)

This page will track the activities related to the winter aeration of Rice Lake for the 2021-2022 season. Most recent activities are at the bottom of this page.
September 30, 2021 - Winter Aeration permit approved by MN DNR
​The Minnesota DNR approved operation of the winter aeration system on Rice Lake for the 2021-2022 season. (Click here to view the permit)
September 23, 2021 - City of Maple Grove provides Certificate of Liability Insurance for system operation
​The City of Maple Grove provided insurance coverage for running the aeration system off City property. (Click here to view the policy information)
This page was last updated on: July 4, 2022
Number of visitors since November 21, 2020

Started at 226
November 4 & 11, 2021 - Winter Aeration public notice in Osseo-Maple Grove Press
​Per Minnesota DNR requirements, a public notice must be run in the local newspaper prior to any operation of the winter aeration system on Rice Lake for the 2021-2022 season. (Click here to view the permit)
December 30, 2021 - Winter Aerator started up and Thin Ice signs posted
​A volunteer crew of RLAA board members drilled some start-up holes and posted 12 Thin Ice signs around the anticipated perimeter for open water. At least 3 diffuser holes seeem to be open at this time; waiting for remainder to open. Please use caution when in this area. The aeration unit will run on a 24/7 schedule until the ice breaks up in the spring. (Click here to view the aeration area map)

Day 1 (12/30/2021) photos
Pilot holes were drilled to help aeration unit open up water today. Thin Ice signs were posted around the anticipated perimeter of an area 150' x 500'.
Soon these individual openings will meld into a single large opening.
The ice depth in this location is about 9".
Note: A hockey rink had been groomed in the approximate vicinity of the expected open water area. Owners of the rink were asked to relocate it.
Why do we aerate? Click here for some background.
View from west looking eastward (hockey rink on the right will be eliminated once the aeration area opens up).
View from east looking westward towards I-94.
View from the shoreline near the aerator power station (see green box in the lower left foreground).
Redeploy missing duck decoys on 10/30/2021
During the course of the open water season, several of the duck decoys used to mark the aeration diffuser heads were lost. Volunteers waded into the area and replaced them with 2 swan decoys and a additional duck decoy.
See below for photos of various activities related to Winter Aeration
Day 2 (12/31/2021) photo
2 diffuser openings of 6' in diameter and 1 opening of 3' as of today, about 20 hours after starting system. (view looking south from aerator shoreline)
Day 4 (1/2/2022) photos
Even after the current 2 day cold snap, more of the ice has been opened up. As of this afternoon, there were at 5 open holes each being about 8' in diameter.
Thanks to Hente Braam for these photos.

2 diffuser openings of 8' in diameter are shown here. (view looking south from aerator shoreline)
2 more diffuser openings of 8' in diameter are shown here. (view looking southeast from aerator shoreline)
View of 3 diffuser openings of 8' in diameter is shown here. (view looking southwest from aerator shoreline)
Day 5 (1/3/2022) photo
Area where 6th and final diffuser should be, but isn't visible yet. (view looking southeast from aerator shoreline)
Day 15 (1/13/2022) photos
East end where 2 swan decoys mark the aeration area. (view looking southeast from aerator shoreline)
West end where area is beginning to open up more. (view looking southwest from aerator shoreline)
The hockey rink was moved to the west on the edge of the aeration area. (view looking west from aerator shoreline)
January 13, 2022 - All Diffusers working at this time
​All 6 of the aerator diffusers appear to be operating at this time. The west end of the aeration area is more open than the east. The hockey surface has been moved by local residents to the west end of the aeration area. See below (Day 15) for the latest photos.

February 20, 2022 - Reduced to 4 Diffusers to improve impact
​Over the past month we have not noticed any increase in the open area. Today we turned off 2 of the 6 diffusers with the hope that the extra power may divert to the remaining 4 diffusers and open up a larger area.
Lower dissolved oxygen levels were also recorded the past week at various locations around the lake, indicating it may be possible that we will experience a winterkill (fish). We are working with other resources (City, Three Rivers, DNR) looking for possible solutions.​

Looking ENE at the edge of the aeration area there are still 6 separate openings with no expansion. Two (2) of the 6 diffusers were turned off to see if extra power could be diverted to the remaining 4 to open up more area.
2/25/2022 photos
3 days after the 2 diffusers were redirected to the remaining 4 diffusers, we are still not seeing any improvement in more open water area. The temperatures were cooler than normal the past several days. See what transpires after the upcoming warm-up the next week.
7 days after the 2 diffusers were redirected to the remaining 4 diffusers we are finally seeing some improvement in more open water area. Note the 2 ducks in the farthest opening (the swan to the right is just a decoy).
3/4/2022 photos
March 4, 2022 - Dissolved Oxygen levels slightly better by aerator today
​Readings taken today just outside of the aeration area were a little better than the past 2 weeks, giving some hope that a winterkill may not be as impactful as it looked last week.
As of today, most of the diffuser openings are connected, providing a larger area of open water.
3/13/2022 photos
3/18/2022 photo
Today, all 4 of the activated diffusers are running producing a single area of open water.
April 7, 2022 - Winterkill has resulted in dead fish this spring
We are seeing vast numbers of dead fish, mostly sunfish, so far this spring. Birds have been feasting on the remains. As mentioned previously, RLAA does plan to restock with game fish this season if the number of dead fish is considered significant.
April 9, 2022 - Thin Ice signs have been recovered for the season
Thank you to Hente Braam for picking up the floating Thin Ice signs today from the lake as the ice finally goes out. The aeration system will be shut off this coming week once 100% of the ice is gone.
4/9/2022 photo
Hente collecting the Thin Ice signs and a couple of stray aerator decoy markers in his canoe today.
April 13, 2022 - Thin Ice signs have been recovered for the season
Winter aeration system has been turned off for the season. Only remaining task is to collect the shoreline Warning signs posted in 4 locations.