Water wranglers balance water levels, river flows in Glen Lake watershed

High water levels early this summer on the Crystal River made “shooting the tubes” difficult, before water levels began their seasonal drop in August. Photo by Joe VanderMeulen

By Joe VanderMeulen

Sun contributor

Meet Bill Meserve and Cal Killen, two of the people responsible for managing water levels in the Glen Lakes as well as the Crystal River. Under the auspices of the Glen Lake Association (GLA), these volunteers serve on the Water Level Committee appointed to balance the needs and demands of both lake shore and river’s edge owners, as well as the businesses that depend on these stunningly beautiful and fragile water resources.

The purpose and goals of the Water Level Committee were set by Michigan’s Circuit Court in response to lawsuits in 1954 and 2001. The 1954 settlement directed the GLA to maintain the water level in the Glen Lakes at 596.75 feet above sea level, using an old dam structure at the outflow of Little Fisher Lake—the beginning of the Crystal River.

That old 18-foot wide dam used stoplogs—just heavy boards—in the flood gates to roughly control the amount of water discharging from Fisher and Glen Lakes. This old technology worked, but not easily.

In 2000, the GLA contracted to have the Crystal River Dam rebuilt with more precise incremental control over the outflow. But trouble soon followed as the construction project interrupted flow into the Crystal, resulting in another lawsuit. This time, the court directed the GLA to more precisely control water flows to protect the Crystal River ecosystem while keeping Glen Lake water levels fluctuating within a prescribed range.

“The courts gave us target lake levels for the summer and for the winter; the difference is about 3 and ½ inches,” Killen explained. “We like to keep it high in the summer for boat activities and low in the winter to prevent ice damage on properties. The court also gave us limits on water flow through the Crystal River. We cannot go under 31 cubic feet per second (CFS) unless the lake level in Big Glen is far below normal. After that, we have a water sharing plan to share the lack of water in both the lakes and the stream.”

In general, kayakers going down the river would prefer flows of 60 CFS or more. When flows are lower than that, say 38 or 40 CFS, there may be places where paddlers will need to work harder to get downstream, even getting out and walking over some bottom lands. But too much water can also create problems, filling culverts and potentially causing erosion and flooding along the Crystal River.

With Lake Michigan’s water levels at near record highs this year and inland groundwater levels up too, you might think that would spell trouble for Glen Lake and Crystal River. However, the two levels are not so clearly linked. According to the US Army Corps of Engineers, the water level of Lake Michigan for August 23 was about 581.73 feet above sea level—15 inches above their level from the same time in 2018. Inland a mile or more and upstream from Lake Michigan, the Glen Lakes have water levels that are regulated by the Crystal River Dam to stay within a few inches of 596.75 feet above sea level.

As Meserve points out, Glen Lake discharges through the earth as groundwater seepage to Lake Michigan. So, even higher groundwater doesn’t impact Glen Lake levels much. Apparently, precipitation is the biggest factor influencing the amount of water going over the dam and heading down the Crystal River. And this past spring and all the way into July, there was quite a bit of rainfall.

“We flowed more water in July than I can remember,” Meserve said, “July was an unusually wet month. Usually, in July and August, we get very little rain and the level drops well below the court ordered level and there’s nothing we can do about that. It’s just nature.”

So how much water is that? According to Killen, the Water Level Committee was able to flow 65 CFS in early July, providing a fast-moving Crystal River and an easy paddle. Early in the summer, water levels were so high that officials stationed at the Crystal River culverts on County Road 675 actually dissuaded paddlers from going through the culverts. However, as the rain subsided, the flow dropped to about 38 CFS—a good float, but requiring some paddling. It’s all related to rainfall.

“If mother nature gives us enough that we can flow 60 CFS,” Killen says, “we’ll flow 60.”

Of course, managing the level of water in the Glen Lakes that are about 6,000 acres in size and up to 130 feet deep is not a simple matter. Water Level Committee Chair Bill Meserve says the outflow at the dam is only a part of the water budget for this lake and river system.

“The elements that control lake levels are evaporation, rainfall, and springs that come into the lake, mainly on the east shore,” Meserve said. “And underground seepage to Lake Michigan (a discharge of water through the ground). We do the best we can by raising and lowering the dam.” He estimates that flows at the dam represent about 30 percent of the total water level impacts.

The fact is, nature plays the most important role here. Meserve says, “The natural forces are more important than what we can control with the dam.”

However, the GLA’s dam managers remain undaunted. Composed of 15 dedicated and particular volunteers, including skilled engineers, the Water Level Committee has been working to improve water level and river flow controls by adding electronics and sensors to inform their decisions at substantially less cost.

Compared to the old methods, Killen says the electronics “can do a much better job of accurately measuring the water levels of Big Glen and the river flow of Crystal River.”

Officially, the court-mandated water level for the Glen Lakes is measured at three staff gauges—like measuring sticks—set at three different points around the lakes and surveyed in place for accuracy. However, it’s not always possible to get a precise reading in windy conditions or when ice and snow obscure the markings on the gauge.

That’s where engineering and electronics come in. In 2010, Killen and his colleagues with the GLA began work on an underwater, pressure sensor system calibrated with the staff gauges. Today, three sensors are used to measure and transmit the water level to three communication stations. Each station is a small feat of electrical engineering incorporating a data logger, battery, solar panel, and modem to transmit measurements every 15 minutes to a website used by the Water Level Committee.

“We also have written software on a website that takes the levels of the water and the height of the dam gates, and converts that to the CFS flow at the dam,” Killen said. The website gives Water Level Committee members accurate and continuous monitoring data allowing very fine adjustments to the gates in response to changing weather conditions. 

Committee members take turns every week visiting the dam, checking conditions and regularly adjusting the gates to fine-tune flows into the Crystal River to maintain Glen Lake levels. As Meserve and Killen point out, this is serious, court-mandated business that requires close attention by the GLA.

Thankfully, the GLA’s Water Level Committee now has the real-time data to make informed decisions, perhaps heading off future challenges.