After I scoped out the swim site yesterday, I decided to check out the lakefront at North Avenue Beach. The cumulative winter winds and waves over the past 20-30 days have created a fairly continuous ice shelf that extends out quite a ways over the water:
Unfortunately, many people walk over this without even realizing that there is essentially nothing underneath them but an icy lake:
Remember – just because there’s ice on top doesn’t mean that there’s dry land underneath supporting it.
Dave was out clearing the ice off of Ladder #1 yesterday and took this shot:
As you can see, the big wave action earlier in the week froze over onto the concrete embankment. In some areas, the ice was over three feet thick and quite hazardous to anyone who might be walking near the lake’s edge. Which reminds me…
A few days ago, a Chicago woman was frolicking near the lake at night with her dogs and had an unfortunate accident:
…the outing turned perilous when she and her dogs slipped off an ice-covered break wall into freezing Lake Michigan and were unable to climb out.
Although this incident took place down in Hyde Park, the circumstances are practically identical to those at the lake front area just north of Oak Street Beach. Bottom line, if you fall in anywhere off of the north or east break walls, there is no way for you to get out of the lake unless you swim the 1/2 mile to Oak Street Beach (which I can personally attest is quite a chilly experience this time of year).
This is one of the biggest reasons we hound the Park District every Labor Day to keep as many ladders as possible in place at Oak Street Beach throughout the year.
So if you happen to see one of us out at Ladder #1 clearing off the ice, please note that it’s not just so we can have an easy entry and exit to go swimming. It’s also to provide a quick exit for anyone who might have the bad luck – or foolishness – to inadvertently fall in.
Because without the proper gear or preparation, you’ve got about three minutes left on your life clock once you hit the lake this time of year…
Paul Meador, a long time Ladder #1 stalwart, turns 80 years young today. Per Dave:
Paul has been guarding Ladder #1 at Oak Street Beach for at least 78 years (I have seen the photo of Paul with his father [at the lake] when he was two years old).
Check out yesterday’s Tribune piece, “State waging chemical war on Asian carp tonight.” In a last-ditch effort to prevent the fish from gaining access to the Great Lakes, Illinois Department of Natural Resources is using the pesticide rotenone.
(Tribune photo by William DeShazer / December 3, 2009)
Last week I attended the very thought provoking event called Water: The New Oil? The featured speaker was Debra Shore, a Commissioner at the Metropolitan Water Reclamation District. Her presentation provided a very comprehensive overview of the unique geography of the Chicago metropolitan area. But what I found to be particularly fascinating was how one simple canal has substantially impacted Lake Michigan and our water supply.
I spoke with Debra briefly after the event, and she was kind enough to have her office forward some of the presentation graphics for this posting. So let’s take a look at the unique geography of Chicago and how the modification of this geography has affected what’s known as the Lake Michigan Watershed.
Around 15,000 years ago, the entire Great Lakes basin was covered in glacial ice more than a mile thick in some areas. As this massive ice shelf receded, it carved out countless fissures and valleys, redistributing vast amounts of soil in the process.
One of the local by products of this glacial retreat was the formation of the subcontinental divide, a ridge of raised earth that separated the Des Plaines river basin from the Chicago River and Calumet River basins. Modern day Harlem Avenue roughly runs over this raised section of terra firma.
Historically, the Des Plaines River drained westward into the Illinois and Mississippi rivers, eventually reaching the Gulf of Mexico. By contrast, the Chicago and Calumet rivers drained into Lake Michigan.
An important item to note here is that any rain that fell to the east of the subcontinental divide served as a significant source of fresh water replenishment for Lake Michigan.
Up until 1900, the Chicago River was the city’s defacto “sewage system.” With human and industrial waste being expelled directly into Lake Michigan, the mouth of the Chicago River was a literal cesspool. And the now prime real estate known as Streeterville was a disease-ridden squatters’ camp nicknamed “The Sands.” In fact, the Chicago lakefront was so polluted that the only way to effectively provide clean drinking water was to build the water intake cribs two or more miles out in the distance. But by the late 1800’s, even that wasn’t far enough away.
So the city planners at the time came up with a radical solution – namely, to reverse the flow of the Chicago River by creating a canal from the Chicago River to the Des Plaines River. And in 1900, the Chicago Sanitary and Ship Canal was completed:
In order to do this, however, they had to create a breach in the subcontinental divide and disrupt an ecosystem that had developed and existed for thousands of years.
Before the Canal
After the Canal
There are two things to note here:
1) Fresh water sources (i.e. rain water) that used to drain eastward into Lake Michigan via this watershed now instead flow westward
Here’s a graphic which illustrates the diverted portion of the watershed that now no longer replenishes Lake Michigan:
2) Lake Michigan itself is now draining into the Gulf of Mexico
Bottom line, since 1967, when more accurate measurements began, it is estimated that over 30 trillion gallons of fresh water have been taken away from Lake Michigan.
The key point here is that we’re witnessing Newton’s Law on a grand scale. Namely, to every action there is an equal and opposite reaction. When you radically alter an existing system in nature – even if it is for a seemingly noble purpose – you’re going to get a radical reaction somewhere down the line. And it may not be an instant and obvious one, either.
So keep all this in mind whenever you look out on Lake Michigan. And don’t let its vastness mislead you. Remember – it may be big, but that doesn’t mean it’s infallible.
There’s a very interesting piece in today’s Chicago Tribune highlighting the speculation that the City of Chicago is considering privatizing its water system much like it has done with the parking meters and the Chicago Skyway.
Check out the whole thing and feel free to comment. I’d be interested in everyone’s opinion on this.
Lake Michigan has held fairly steady in the 55F+ range. But we’ve noticed a recent downward trend in the water temperatures that most likely indicates the beginning of the fall turnover.
To give you a quick overview, during the summer the warmer air temperatures and longer periods of sunlight heat up the lake causing it to form three separate layers:
Candidly, I don’t think we every really got a very deep epilimnion layer this summer. And with a colder thermocline lurking not too far below the surface, it’s easy to see how we had that goofy 55F cold spell in August that sent everyone shrieking out of the water.
But the fall turnover is something far more enduring. This takes place when the weather cools down during autumn and the sunlight diminishes on both ends of the day. As the surface temperature drops and the increased winds churn up the lake, the thermocline gradually deepens until the colder bottom layer starts to mix with the upper layers. This phenomenon is known as the fall turnover.
Once the fall turnover takes place, we are at the “point of no return” as far as water temperatures are concerned. The lake will eventually form another surface layer during the winter months, but this will be much colder – and will eventually freeze over. The rest of the lake will be a uniform 39F until the spring winds, air temperatures, and sunshine mix up Lake Michigan for the spring turnover.
The key is, there’s no such thing as an “Indian Summer” when it comes to deep lakes like Lake Michigan. Once the fall turnover arrives, say goodbye to 50F+ water temperatures.
Every so often cities such as Chicago, Evanston, and Wilmette will close down their beaches due to higher than normal bacterial counts. Have you ever wondered why that happens?
In this podcast, we speak with Todd Connor who is a candidate for Commissioner for the Metropolitan Water Reclamation District of Greater Chicago. Be sure to listen in as we talk about the history of the district, how it operates, and why we should be concerned about who’s watching over Lake Michigan.
