Rochester Public Utilities | Blog

Archive for October, 2017

Lake Zumbro Hydro Drawdown Schedule Revised

Tuesday, October 17th, 2017

New drawdown schedule

  • November 9- Start drawdown at 0.5 feet per day
  • November 16- 911.5 Annual dam inspection
  • November 17- Inspection and work near intakes 
  • November 23- Start to refill lake to winter pool elevation of 913.0
  • November 25- Maintain winter pool level at 913.0 through March 2018

The annual drawdown of Lake Zumbro is scheduled to begin on October 28th. The drawdown is necessary for planned maintenance and shoreline restoration work.  The public should be aware that the drawdown planned for this fall will be substantially greater than normal.  A typical fall drawdown is less than two feet; whereas this year a seven foot drawdown will be attempted.  These plans are subject to change depending on rainfall and resulting runoff.  RPU’s drawdown plan is as follows:

  • Sunday, October 28th start the gradual drawdown from summer pool elevation 914.5 and continuing releasing water until a target elevation of 907.5 is achieved.
  • Maintain the lake level at or about 907.5 from November 12th thru November 15th.
  • On Thursday, November 16th the lake refilling will begin. The level would be slowly raised back up to normal winter pool at a rate no more than 0.5 feet per day while maintaining a minimum release of 70 cfs.  We anticipate a minimum of 11 days will be required to raise the lake level to normal winter pool of 913.0 to minimize the impact on downstream resources.

The drawdown plan is subject to change depending on weather conditions.

During the months of November through March, Rochester Public Utilities (RPU) will attempt to maintain the lake level at the winter pool of 913.0.

Real-time lake level information, along with Lake Zumbro hydro updates are available on the RPU web site ( For additional information regarding the Zumbro Hydroelectric Facility please contact Tony Benson at (507) 280-1534.


Tips for lake ice safety:

Be extremely careful during winter activities that involve Lake Zumbro such as ice fishing, snowmobiling or just walking out on the frozen lake.

Watch the weather and river flow conditions.

Ice thickness and condition can vary greatly. Be very cautious.

Look out for ice heaves and exposed logs and snags.

Be cautious in the vicinity of the dam. De-icing equipment has been installed along the upstream face of the dam resulting in open water and/or thin ice.

Do not proceed past the warning signs and buoys.



About Rochester Public Utilities


As the municipal utility of Rochester, Minn., for more than 110 years, RPU provides high-quality and reliable electricity to over 50,000 customers.  Water customers number more than 37,000.  RPU continually investigates innovative technologies to help customers realize the best value from the services they receive.  Current initiatives include photovoltaic offerings, wind energy, energy and water efficient equipment, and electric vehicle charging.