This article was written in conjunction with Richard Thompson of the Leland Dam Authority.
Over the past few years, a number of riparians have expressed concern to LLLA or the Leland Dam Authority about the water level of Lake Leelanau. Some individuals expressed frustration that the high water level caused flooding of their lawns or foundation or both. Other people were concerned that low water levels caused navigation problems. On April 15th, the Dam Authority implemented their mandate to raise the level of Lake Leelanau by one foot. Please read on to understand why this annual adjustment is made.
How do lake levels impact the shoreline?
As many of you may have noticed, the water level of Lake Leelanau fluctuates. There are 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.
Read about our Shoreline Steward program to understand how a natural shoreline can protect your property from erosion
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 negative 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:
- 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 (File No. 78-610-2-P2) was issued in the Circuit Court of the County of Leelanau to establish the lake’s level. Based on studies, the optimal level was set at 589.21 feet above mean sea level on April 15th (or the last ice) and lowered to 588.21 feet above mean sea level 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 oversee the maintenance and operation of the dam system to control the lake level as mandated by the court order. A designated County employee is assigned to monitor the lake level, monitor weather conditions, and adjust the dam gate to maintain the water level to comply with the Court order.
- 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. These sensors are located at the Leland Dam, the Narrows, and Birch Point at the south end of South Lake Leelanau.
The Sensors Monitoring Lake Leelanau’s Levels
Since installing the three 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.
During extreme weather events such as heavy rains over the entire watershed, the lake level may temporarily exceed the court mandated level. The county dam operator adjusts the dam gate to bring the lake level back to the court-ordered level.
Periodically, staff gauge readings are taken to verify that the electronic lake level sensors are reading correctly. If the sensor readings do not agree with the staff gauge readings, an adjustment is made to the electronic sensor. If a sensor cannot be brought into agreement with the physical staff gauge reading the sensor is replaced.
You can view the real-time sensor data displaying lake water levels and temperature from the three sensors on our website.
The Lake Leelanau Lake Association displays the data, but the responsibility for maintaining the water level resides with the Leland Dam Authority and the County employee operating the dam to keep the lake level in compliance with the court order. We hope this clarification about the legally mandated water level and the responsibility for maintaining that level may be of value to our riparians and others who use and enjoy Lake Leelanau.
Featured Image Photo credit: Jeremy Thompson (CC By 2.0)