Reprinted from the earliest days of McHenry County Blog, the time when articles were wiped out by Google after its labeling this publication a “spam blog.”
Crystal Lake’s Lake Bottom in Good Shape
1-4-7 For those worried about what local residents have done to Crystal Lake, there is good news from the Illinois State Geologic Survey.
That’s what was found from a 30-foot core sample taken while the ice was frozen.
That means Crystal Lake at one time was 72 feet deep.
I figured that it was time to call Geologist Brandon Curry back for an update on what he found while doing a project for the Crystal Lake Park District.
To put it Curry’s words:
We took a core from ice near the center of the lake in 42 feet of water that was 30 feet long….
That’s 30 feet of sentiment filled in since 16,000 years ago. Of that 30 feet, about 2 feet of it is post-settlement.
“That is so exciting!” I said.
“That’s not a lot of guck,” was the reply.
“Is that a new scientific term?” I asked.
“We use terms like that all the time,” Curry revealed.
“The equipment would not work accurately in water shallower than about 10 feet.
“In many places where it is shallow (less than about 6 feet deep), rocks are visible, so there has been little or no siltation in those areas. That covers quite a bit of the lake.
“Much of the water in the West End is so shallow that a geologist had to jump into the water with a measuring stick.”
And, there’s more work to be done. Curry says for $15,000 he could study droughts over the last 2,000 thousand years.
Tomorrow, what about the West End?
= = = = =
In late December before the ice disappeared, these geese were sitting on what was left near Gate 5. When I got close, they took off.
The bathymetric map show is from 1957. Presumably the deepest spot remains where the darkest spot is on this map.
Off to the right of the boat is the device that measures the depth of the lake. The bottom two images were provided by the State Geologic Survey this past May.