Manitowish Waters Dam : The Fall Draw Down – The When and the Why

The water level in the Chain above the dam will likely decrease from its current level and reach 8’0″ sometime shortly before October 1st.

Then beginning on October 1st, the level will be drawn down from 8’0″ to reach the final winter level on or before October 31st. 

The operation of the Rest Lake Dam is guided by the Memorandum of Understanding (M.O.U.), a document that was signed in April of 2016 by the Chippewa – Flambeau Improvement Company (Xcel Energy) and the State of Wisconsin.  This agreement does not replace the work order that was signed in the 1930’s but adds more detail to it.  It is a step in the process that attempts to provide some compromises relative to upstream (above the dam) and downstream (below the dam) interests.  It also attempts to keep in mind ecological needs and navigational needs both above and below the dam.

To understand the timing of the fall draw down, it is helpful to understand the way the dam is operated in summer.  The summer level of the Chain above the dam is actually a range rather than a single specified level.  That summer range is 8’0” to 8’6”.  The Chain has been 8’3” or greater much of the summer.  It is also helpful to remember that September is considered part of the summer relative to the M.O.U.

In later September, Xcel energy decreases the level of the water above the dam and increases the flow of water below the dam to be at or near 8’0” by October 1st.  Per dam records, this occurred between Sept. 28 – 30 in 2016; between Sept. 27 – 30 in 2017; and on Sept. 28, 2018, the level of the water above the dam was 8’2”.

Beginning October 1st, the water level is drawn down to reach the winter level by October 31st, the date specified in the M.O.U.  This operation of the dam in September and October allows the owners of the dam to accomplish a difficult task, to drop 3’5″ of water over 4000+ acres of lakes and channels by October 31st.

Hopefully, this information will be helpful for those who need to keep in mind when they can expect to see some drop of water level above the dam and an increase in water below the dam and plan accordingly.