Background on Rice Lake drawdown needs
The lake is controlled by a dam on Elm Creek. This allows the Rice Lake Area Association and City of Maple Grove to control the lake level when necessary. The lake basin receives water from various sources (creeks, residential and commercial drainage systems, etc.) which cover over 100 square miles in the northwest Hennepin County area. High levels of phosphorous enter the lake from these many sources and contribute to accelerated and heavy weed growth. In some situations, this heavy weed growth impedes or halts navigation by water craft.
There has been an on-going increase in the presence of the non-native Curlyleaf Pondweed (CLP) since the last whole lake treatment via drawdown was conducted over the winter of 2004-2005. A 2014 Aquatic Plant Study was conducted and showed the highest number of CLP plants since 2005. A Fish Survey was also conducted this year and evidence shows a disproportionate number of rough fish (common carp and bullhead) to the number of game fish. Both project consultants recommended a drawdown without aeration to both reduce the CLP growth and to try and eliminate more rough fish (winter kill).
How does a Drawdown work?
A drawdown done during the winter months exposes the lake bottom to the elements. A good hard freeze could be very beneficial in stunting the growth of weeds for the next year and possible future years. The native plants are accustomed to the elements and should not be impacted during a drawdown.
The Minnesota DNR Fisheries contact has agreed that by not running an aeration system during the winter months would help eliminate the remaining fish in the lake, and allow us to restock the following year (2015) with game fish.
How does the Drawdown Process Work?
The procedure for requesting a drawdown is different than when last sought in 2004-2005. The Minnesota DNR incorporated a new process in 2012 with these requirements:
- Requesting party (RLAA) must demonstrate the need for the drawdown by following these steps:
- Get at least 75% sign-off from riparian residents (lake/creekshore owners)
- Show evidence that drawdown is needed for non-native plant control.
- Public entity must submit the request (not the lake association)
- That public entity sponsors the request and submits a request to the DNR for the drawdown.
- The DNR asks the public entity to host a public hearing to announce the drawdown.
- MN DNR reviews the request and approves/rejects it
Who Advocates the Drawdown for 2014-2015?
RLAA has received support for conducting a drawdown by the following parties:
- Freshwater Scientific Services (Aquatic Plants consultant)
- Blue Water Science (Fish Survey consulant)
- West Metro Fisheries (DNR)
- Three Rivers Parks District
What is the Current Status for the Drawdown?
As of October 24, the bypass at the dam behind the high school was opened up to allow water to pass under the dam. Typically it takes 3-5 weeks for the water level to reach it's minimum (a drop of between 5-6 feet), assuming there are no physical barriers preventing the water flow from the Elm Creek inlet to the dam bypass.
- 10/24 - Bypass at the dam was opened up to allow water to flow around/under the dam.
- 10/25 - Water level has dropped almost 12" already!
- 10/28 - Water level has dropped approximately 18" so far.
- 10/29 - Water level has dropped 24".
- 10/31 - Water level has dropped total of 30" so far.
- 11/4 - Water level has dropped to total of 48".
- 11/7 - Water level down to 60" below normal so far.
- 11/24 - Water level down to 56" (4.82 feet) below normal. This may be the maximum attained going into the freeze season.
- 3/14/2015 - The City may be closing the bypass gate at the dam this coming week as water levels in Elm Creek begin to rise from melted snow in the watershed. Once we get official word the dam will be closed, we will share with everyone. In the meantime, you should probably complete any work you are doing in the exposed shoreline.
- 3/17/2015 - The City Public Works department closed the gate at the dam to begin refilling the lake for the season.
- 3/30/2015 - City Public Works department readjusted gate at the dam, which was not completely closed since March 17. Water should now begin to refill the lake as expected with normal flow.
- 4/13/2015 - First of several fish restocking completed with young perch and crappies.
- 4/17/2015 - Second fish stocking installation done with young crappies, bluegills and largemouth bass.
- 4/25/2015 - Lake water level roughly 3 feet below normal. Inflow from Elm Creek is also much lower than normal, as is the outflow NE of Rice Lake up to the Mississippi River.
- 5/1/2015 - Water level still approximately 3 feet below normal at this time. Dam is operating as expected.
- 6/5/2015 - Water level is approximately normal high water at this time (890 feet above sea level).
Drawdown Preparations
- A formal request was submitted to the City of Maple Grove to sponsor this request in August.
- Signatures were obtained from at least 75% of the residents living on the creek/lake (80% were received).
- City submitted an on-line request to notify the DNR about an intent for a drawdown this winter.
- City set up a Public Hearing for comments on the planned drawdown.
Hearing will be conducted on Wednesday, October 15 beginning at 6:30 pm at the Maple Grove
Government Center during the Lake Quality Commission (LQC) meeting.
All are welcome to attend this Public Hearing.
- City posted the Public Hearing notice in the Osseo-Maple Grove Press on Thursday, September 25.
- Public Hearing held on October 15 at the Maple Grove Government Center during the monthly Lake Quality Commission meeting. The LQC approved the drawdown request 8-0, with the requirements that RLAA will restock game fish in 2015 and do winter aeration in the future years after the restocking to sustain the game fish population.
- 10/20 - City Council approved drawdown request unanimously. Next step - submit to DNR.
- 10/22 - DNR approved the drawdown request; City to send out notification letters to residents. Drawdown is scheduled to begin on Friday, October 24.
Restocking Project
With the help of the City of Maple Grove, RLAA has stocked more native game fish this past season. Besides improving the game fish habitat and water quality, these species can feed on the young of both carp and bullhead. Note: All fish stocked were young, except for the 10 pair of adult largemouth bass. Among the species and number of fish stocked were:
- 10 pair of adult largemouth bass
How low can we go?
- Past drawdowns have experienced these maximum declines in water levels:
Comments
- The DNR has allowed us to extend this request beyond the normal guidelines of 30 days prior to drawdown start date for reviews/approvals.
- The DNR has recommended that silt fencing be set up along major roadways along the waterways to help prevent aquatic critters (frogs, turtles, etc.) from crossing into traffic areas.
- Remember that the drawdown will give residents an opportunity to observe their exposed shoreline to determine what work, if any, needs to be done. This will also be a good time to clean up debris normally not visible beneath the water surface.
- Thanks to those who attended the Public Hearing and voiced their opinions.
Thank you for your patience as we pursue this project to improve the quality of our lake/creek!
Post Drawdown Summary
- Was the drawdown successful?
- Yes, the Curlyleaf Pondweed growth was reduced substantially and native vegetation growth has improved.
- The drawdown did not have much of an impact on the carp and bullhead population has no fish kill was seen.
- Are their plans for another drawdown?
- Not at this time. If future Curlyleaf Pondweed growth warrants it, another drawdown would be possible.
