April 15th is Lake Leelanau’s Lake-Levels Rising Day—the day when Lake Leelanau’s water level is raised by a foot each spring! Please read on to understand why this annual adjustment is made.
Recent blogs have focused on ways to protect the lake’s water quality by protecting the shoreline. This week, we will look at how the lake’s levels affect the shoreline and why and how managing water levels keeps Lake Leelanau and its shoreline beautiful and healthy for all to enjoy.
How do lake levels impact the shoreline?
As many of you may have noticed in the past, the water level in the lake can fluctuate from periods of higher water levels to periods of lower levels. There are different consequences when water levels change.
Higher water levels can:
- Increase erosion and loss of shoreline;
- Increase sedimentation, which may adversely affect the lake’s water quality;
- Damage property and shoreline vegetation;
- Cause the flow of contaminants into the water; and
- Restrict access to roads and water access points.
On the other hand, lower water levels can:
- Increase navigational challenges for watercraft, which affects both recreational and commercial users;
- Alter ecosystems; and
- Affect fish reproduction.
The History of Lake Leelanau’s Lake Levels
The goal for lake managers is to find a happy medium to avoid the above consequences. In the 1970s, the challenges of finding a happy medium for Lake Leelanau’s water levels were raised. The community-wide discussion which ensued led to the creation of the Lake Leelanau Lake Association (LLLA). Here’s a brief history of how that came about.
- In 1970, a group of concerned individuals wanted to file a lawsuit with Leelanau County to establish Lake Leelanau’s water level. This group later became the LLLA.
- In 1978, a court order was issued to establish the lake’s level. Based on studies, the optimal level was set at 589.21 feet on April 15th (or the last ice) and lowered to 588.21 feet after November 15th to account for the ice cover in the winter. The level is regulated by lowering or raising the county-owned Leland Dam, which adjusts the level of Lake Leelanau via the Leland or Carp River.
- In 2004, the Leland Dam Authority was formed by Leelanau County to be the official group responsible for maintaining the dam and the lake’s levels. The court order of 1978 specified that the lake level was to be measured at the Leland Dam.
- In the early 2000s, the dam was upgraded to replace the previous “stop log” system with a hydrologic system controlled via a control house with specifications to pass up to 1,200 cubic feet/second of water in case of the “200-year flood.”
- In 2016, three water sensors were installed to better monitor Lake Leelanau’s lake levels in case adjustments are needed to maintain the lake at the court-ordered levels. These sensors are at the Leland Dam, the Narrows, and Birch Point at the south end of South Lake Leelanau. You can view the data received from the sensors here.
Lake Leelanau’s Levels Today
Since installing these sensors, the community has more precise information about how the lake levels naturally fluctuate and how these fluctuations affect different parts of the lake. This information allows the Dam Authority Board to make better decisions on managing the water levels via the Leland Dam.
Earlier this year, the Leland Dam Authority Board was restructured. The board will be taking a closer look at issues related to the sensors, their calibration, and Lake Leelanau’s water level management.
Lake Leelanau’s lake levels will rise by one foot in a couple of days as summer approaches.
While it takes a few days to see this change throughout the lake, we invite you to take a little extra time to look at Lake Leelanau’s shoreline in the next few days to see if you notice a change. Even if you cannot tell the difference, at least you will benefit from some extra time spent admiring the beauty of our lovely Lake Leelanau!