Rest Lake Dam Draw Down
The Fall Draw Down The When and the Why
The water level in the Chain above the dam generally decreases from its summer level to reach 8’0″ sometime shortly before or on October 1st.
Then beginning on October 1st, the level is 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 (MOU), a document that was signed in April of 2016 by the Chippewa and Flambeau Improvement Company (Xcel Energy) and the State of Wisconsin DNR. 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 generally is at 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 MOU.
In later September, Xcel energy increases the flow of water over the dam and decreases the level of the water above the dam to be at or near 8’0” by October 1st. Per dam records, this occurred between Sept. 28th and Sept. 30th in 2016; between September 27th and September 30th in 2017; and on Sept 28th, 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 MOU. This operation of the dam in September and October makes possible a drop 3’6” of water over 4000+ acres of lakes and channels by October 31st.
This information may be helpful in understanding the drop in levels of water seen above the dam and the increase in levels and flow seen below the dam in fall.
