The article form January 6, 2008, wiped out by Google on the grounds that McHenry County Blog was a “spam blog” has been found and is re-published here.
The Springs of Crystal Lake
This story is about the springs that supply the crystal clear water to Crystal Lake, the lake.
Illinois State Geological Survey Geologist Brandon Curry was talking about imaging “the sentiment layers below the lake’s sentiment surface.”
After using sonar to map the bottom of Crystal Lake last May at the request of the Crystal Lake Park District, Curry found curious gashes in the bottom.
Eventually, he figured out that they were springs.
You almost have to see it to believe it. You can see individual layers of lake sentiment.
The sentiment layers forming previously unknown places of interest, such as springs. That’s what we found.
There are ten of them. They are peppered pretty much over the southern half of the lake. I would say they are located where there is a break in slope–where the lake starts flattening out is where these pits are.
They’re not all that deep. They’re only about a meter deep. They are about 60 feet across.
They look like giant cracks in the bottom the lake.
The distribution suggests that, if they are gashes, they are not very long.
It has been known that there’s ground water coming into the lake, but we didn’t know that there would be that many expressions of what we call springs. They are subterranean springs, just meaning they are under water, in some cases in 20-30 feet of water.
What we found was worth the price of admission right now. I think the (Crystal Lake) Park District paid about $5,000 for this and they got their money’s worth just finding that out.
Speaking of fishing, I asked Curry if he was able to find posts from the old icehouse.
I found some just west of the Gate 7 Country Club Additions Property Owners Association Beach in shallow water when the lake was down. They were the size of telephone poles and I had long thought that a main structure was out beyond the swimming area and dock at Gate 9. I was led to this conclusion by the many fishermen who drop their lines there.
Now, I wonder if there is a big spring between Gate 7 and Gate 9. I know I can feel spring water coming out of the lakebed just southeast of where the CCAPOA tethers the swimming float.
Curry did find some sedimentation over parts of some of the springs:
One of the things this method does is separate out materials with different acoustic properties. One of those covers some of the springs and the material likely is post-settlement material. I suspect that a lot of the problem with sediment in the lake—and it’s really does not seem to be a big problem.
= = = = =
The top photo is of sunset taken at Crystal Lake’s Main Beach on August 26, 2006.
This raft is in front of Lakewood’s Gate 7 Beach. I know there is a small spring to its southeast and I’m betting there’s a long one running parallel to the beach property slightly beyond the roped off area. This is a 2002 photo.
The two fishing boats seen above are both out from Lakewood’s Gate 3 Beach in mid October–one on a calm day and one in rough water on a blustery day. Are they over one of the springs Curry documented?
And I couldn’t resist including a third fishing photo in the photo explanations. You can see the Crystal Lake Park District’s Main Beach House lights reflecting off the lake at dusk in May, 2006. Maybe it is over the spring where I’ve heard that Indians used to come and clean out the leaves into the 1920’s.
At the bottom is a picture supplied by the State Geologic Survey in May. It shows the computer screen recording the bathymetric readings.