Crystal Lake - the body of water – ranks among the healthiest: ‘Be proud of your lake’

Crystal Lake‘s namesake body of water ranks as one of the best in the country in water quality and chemical conditions, according to a report made for the Crystal Lake Park District.

Hey and Associates, an engineering, ecology and landscaping architecture firm, presented its annual State of the Lake report to the Crystal Lake Park District earlier this month. Its findings, from last year, showed the lake consistently placed in the top percentiles in the state and nationally in terms of water clarity and nutrients.

[ Favorite Northwest Herald photos of Main Beach and Crystal Lake ]

Crystal Lake excels the most in water clarity, with an average of 4 meters, putting it in the 100th percentile in Illinois and the 96th percentile in the nation, Hey and Associates Field Service Manager Jeremy Husnik said. The lake outperforms neighboring lakes like Wonder Lake, Bangs Lake in Wauconda and Lake Zurich, according to the report.

Phosphorus is the main nutrient that affects plant growth, and lower numbers are better, Leonard Dane of Hey and Associates said. With an Illinois Environmental Protection Agency standard is 0.05 milligrams per liter, Crystal Lake’s average value is at 0.024 milligrams per liter, putting the lake in the second percentile in the state and 27th nationally, according to the report.

Crystal Lake’s phosphorus numbers are comparable with Bangs Lake and Lake Zurich, with all of them being glacial lakes. Wonder Lake, an impoundment lake that is more shallow, has six times more phosphorus than Crystal Lake, Dane said.

Overall, Crystal Lake is stable chemically and biologically with water quality rankings higher than national and local lakes, Husnik said. More phosphorus is entering than leaving, making the waters stable, Hey and Associates Ecologist Vince Mosca said.

“Be proud of your lake, because we don’t see many lakes like this,” Mosca said. “You’re going to have long-term protection because of the way your lake is built. With climate change and weather pattern differences, you’ll be more resilient than some lakes.”

Mosca also pointed to the city of Crystal Lake’s own watershed ordinance that goes above and beyond McHenry County’s and further protects the lake.

One thing threatening the lake are zebra mussels. The invasive species originated in Europe and traveled to North America, including the Great Lakes through ocean-going tankers, Mosca said. The mussels eat away at algae making, the water more clear. That might seem like a good thing, but clearer waters means plants can grow deeper in the lake, causing an imbalance in the ecosystem, Dane said.

“If the bottom of the ecosystem is getting too clean, and not enough algae, there could be a crash potentially in the future where the whole bottom of the ecosystem kind of falls apart because the water is too clean, partially because of the mussels,” Mosca said.

Zebra mussels get into Crystal Lake by attaching themselves onto boats and birds. Lake-goers should clean off their boats if they have been in other waters to prevent introducing more mussels, Dane said. Crystal Lake Park District Executive Director Jason Herbster said the district has thought about creating a boat wash-off station at the lake,but faced challenges on how to catch the water used to clean the boats to make sure it doesn’t run off into the lake.

“The other thing is having the staff to make sure people actually do it, and that’s a 24/7 job,” he said.

Last year, Hey and Associates found growing in the lake eight native plants and three non-native plant: curly-leaf pondweed, spiny naiad and Eurasian watermilfoil.

Milfoil returned, mainly at the west bay, with just over 1% of relative dominance in the lake. The return comes after the species seemingly died off after a chemical treatment in 2022, Husnik said.

The native plant eel grass has in the past been a hot topic for residents, as the grass can accumulate on the surface, creating a thick layer that people, animals and boat motors can get tangled up in. Under the suggestion of the Lake Advisory Committee, the park district bought a weed harvester to pull out excess eelgrass in 2023. Since then, the dominance of the plant dropped two percentage points, the report shows.

The Lake Advisory Committee is a group of volunteer citizens who provide concerns and suggestions about the lake. The group is currently looking to get more members, Greg Kobelinski said.

The Main Beach Swim Area at Crystal Lake opens for preseason 9 a.m. to dusk Saturday, May 24, through Monday, May 26, and then from noon to dusk Tuesday, May 27, through Friday, May 30, before opening for its regular season hours of 9 a.m. to dusk seven days a week on Saturday, May 31.