An older view shows it as an active quarry with the I-294 bridge over the access road and a couple of deeper access tunnels.
|3D Satellite, looking South|
Phase I, which is north of the crushing plant and will hold 3.5 billion gallons, will open near the end of 2017. That is why the MRWD is offering tours during 6 days during Aug-Oct. I caught a tour on the first day, Aug 6. After it becomes operational and they let wastewater into the reservoir, I'm sure it will be off limits to public view. (On the tour, I learned that Joliet road is closed between 55th and East Ave. because Vulcan caused a collapse in the road.) Phase II will hold an additional 6.5 billion gallons and is scheduled for completion in 2029. The tunnel system was done in 2006. One reason it has taken so long to dig the reservoirs is that the housing (and construction) collapse in 2008 caused the market for stone aggregate to dry up.
I took a photo of the backdrop that they had for photo shoots because it is a view from the bottom that I knew I would not be able to take myself.
The tour bus first went past their biosolids drying lagoons.
the Centennial Trail from Route 83 because the hill is a long ways from the Columbia Woods Willow Springs Road entrance.
|Satellite view captures Centennial Hill when it was still being constructed.|
We see that drill at about the same location in the photo, but at a different angle. They have just begun the next layer of the dig.
One advantage of taking a lot of pictures is that I can see things when I zoom in on a photo that I did not notice during the trip.
Three more shots as we drove past the wall.
We have had enough rain storms lately to demonstrate that the bottom is not sloped towards the drain. When the guide overheard some of us talking about that, he explained that was deliberate because it makes the reservoir act like a big settling pond. During dry weather they plan to come in and dig out the residual biosolids. So that will reduce the workload on the Stickney Water Treatment Plant.
dolostone. To seal the overburden, they built a 3' wide slurry wall using bentonite. Bentonite is a clay that packs so well it becomes impervious to water.
a video of its arrival.
"Crowds flock to MWRD's Stunning View of McCook Reservoir"
[The article provides a stat I've been looking for: the tunnels themselves can hold 2.3 billion gallons. I also learned that the two grout walls connect with an impermeable natural layer of shale that is under the reservoir at around 325 feet. The age of the dolostone is 400 million years.]