LDA Mission Statement

To promote the protection and enhancement of Detroit Lake

2023 LOW WATER LEVELS

Low Water Levels on Detroit

A number of Lake Detroiter members have observed water levels are quite low this year.   Some neighbors have complained about having difficulty getting boats on and off lifts.  

The main reason for low water this boating season, as in other years, is lack of precipitation.   This year’s lack has been particularly noteworthy.   This year’s precipitation by the end of July only reached a bit more than eight inches.   That’s half the average, and the lowest amount for the first seven months for any of the last 34 calendar years.   

Another prominent factor is this year’s low water level timing.  It is not uncommon to have seasonal water levels lower than our end of July experience this year - that has happened five of the last 13 years.    Indeed the average seasonal range of Detroit Lake levels is close to one foot, but in recent years it has exceeded 18 inches five times and was almost two feet last year.    Moreover, in 2023 the lake is already a foot lower than its springtime high point and these lows often come in August or later; this is the first time in many years to have such low July levels (in the middle of boating season!).

 

 

What can be done?

Aside from rainfall, Detroit’s water levels are mainly controlled by a structure at the outlet, Dunton Rapids.   (Various outlet control structures have been in place at the outlet of Pelican River and Muskrat Lake to Lake Sallie for 135 years,  and the history of Detroit’s lake level management has been described elsewhere – see link to 2023 Lake Detroit Management Over the Years                  ).

Dunton Rapids is an “engineered” rapids, used to permit fish passage, and by a formal agreement with the DNR,  County,  Watershed District, and local governments; it is designed to replicate the flow characteristics of the lock and dam facility that it replaced in 2011.   The structure consists of a series of steps surmounted by carefully placed large boulders.  The DNR has indicated that the structure’s hydraulic attributes are now identical to those of the structures it replaced.   

In view of the recent lake level situation, some Detroiters have suggested that to increase Detroit’s water levels the DNR might be persuaded to increase the rapids height to retain water, thereby raising Detroit’s level.   Two problems come to mind about this suggestion:   one is that such a proposal would undoubtedly be vigorously opposed by shoreline residents on downstream lakes, Sallie and Melissa who could anticipate lower water levels;  the other is that slowing the out-flow during high water episodes would likely increase damage to Detroit’s shoreline, including vegetation and structures.   It is also worth noting that higher water levels tend to erode shorelines and decrease near-shore depth profiles, causing shallower nearshore water depths, surely an unattractive outcome for many shoreline residents.