Tuesday, August 8, 2017

MWRD: Thornton and McCook Reservoirs

Putting the "R" in TARP (Tunnel and Reservoir Plan).

Satellite
Whenever we would drive to Indiana or further east, a significant landmark would be the "big hole" next to I-294. The MWRD bought that "little part" north of I-294, dug it 300' deep, filled the access road under the bridge with roller-compacted concrete, created grout walls, added a 30' connecting tunnel to the Calumet Deep Tunnel System, and opened it in 2015.
It absorbed its first heavy rain flow on Nov. 26-27. (new window)


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.
Birds-Eye View
A more current view shows the damming of the access road.
3D Satellite, looking South
When an article about an award was printed, this was the world's largest CSO (Combined Sewer Overflow) reservoir. But when the MWRD's McCook Reservoir is completed in 2029, it will be bigger.

Satellite
When the Des Plaines and Mainstream tunnels were built, the plan was that they would empty into part of the Vulcun Materials Quarry. But the MWRD and Vulcun could not agree on a price. So MWRD sacrificed 17 of their biosolids drying lagoons to dig a reservoir on their own land. They built a crushing plant that feeds an underground conveyor belt that ties into Vulcan's stone storage, sorting, and delivery facilities.

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.

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The tour started at the Mainstream Pumping Station, but we were not allowed to go down to see the pump houses. They have other tours for that.

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.
Then we passed Phase II, which they are still digging.
The overburden was hauled south to create a recreation hill, Centennial Hill, in Columbia Woods Forest Preserve. Although I hope  I can access 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.
Another overview of Phase II. Near the right, in the middle, is a drill set up to create another hole for explosives. (The tours was on Sunday so nothing was operating.)

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.
Vulcan is in charge of the mining operation, but MWRD had to supply six trucks at $2 million apiece and other equipment. Note that there are three more drills on top of the wall that separates Phases I and II.
The open-air building is where the haul-trucks dump their loads into the crusher. The partial view of the building on the left is used to maintain the equipment.

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.

Specifically, I see there are at least four more trucks parked up on the wall.



Three more shots as we drove past the wall.



On the other side of the wall we can see the tops of two cranes that they are using for some final construction in Phase I. It also appears that part of completing a reservoir is putting a chain-link fence around it.
With 18mm, I managed to get a shot of most of Phase I. In particular, we can see the access road along the far wall. The reason the wall looks darker above the road than below it is because it is lined with a steel net designed to keep any rock falls close to the edge of the road to avoid hitting any trucks.
I stood up to get above the fence to get this shot of a train on the IHB tracks. The truss bridge is over the Sanitary and Ship Canal. This picture makes me appreciate than none of my other pictures picked up window glare. It looks like it is being pulled by a UP engine.
This view is looking back at the Phase I side of the wall. I put a red rectangle around the opening of an old interceptor sewer that they had to reroute around this dig. In fact, the new sewer line was one of the responsibilities of our tour guide, and he was obviously very proud of the work.
The train was a mixed freight.
Now we are off the bus. This is an overview of the overview.
Walking up to the barricades and taking a wide-angle shot down into reservoir.
A tighter shot of the reservoir. The "tiger teeth" is where the Des Plaines Connecting Tunnel enters. The tiger teeth slow the lateral flow and turn the flow into the longitudinal flow that this reservoir needs. They are having to build the new tunnel because the Des Plaines Tunnel had stopped by Vulcan's quarry. You can barely see the two cranes by the far wall.
They would not let us walk down along the left wall so that we could try to see into the tunnel exit that is sticking out a little on the right in this view. I started walking down the road, and I was told to come back. The "drain" to the pumping station is the hole near the back on the right.

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.

Quite a bit of the guides narrative that he read from a Public Relations script concerned the work to keep the dirty water out of the ground water and the ground water out of the hole. They created two grout walls, one near the edge of the hole and another 15 feet away. Each wall was built with 6" holes drilled every 5' to a depth 70' under the floor of the reservoir or 370'. Then they pump grout into the holes under high pressure to fill any cracks in the 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.
Here we see both grout walls, but I'm lined up on the one 15' away. We also see a couple of boys on a rock pile picking out their free rock sample. When I got off the bus, someone commented about how they liked their rocks. Sure enough, I saw one still carrying a big fist full of rocks.
I assume all of those watermarks we see on the walls were made by ground water before they did their grouting.
This was the diagram that the guide used to explain the "plumbing." The arrows on the green line between the "drain" and the pumping station are going in the wrong direction.
It was on the edge of the overview.
I'm now doing a photo dump of the pictures I took when I left since they should be rather redundant.
I took this picture to catch the autotrain that was still rolling by as we left. When I went back to the bus, I noticed it on the IHB bridge. So I waited and made a video of its arrival.




Update:
WaterOnline article
"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.]
MWRD posted
Today [2017 Dec 4] we marked a historic milestone as we celebrated the completion of Stage I of the McCook Reservoir, one of the biggest achievements to date in the MWRD's Tunnel and Reservoir Plan (TARP). The McCook Reservoir will mitigate flooding and prevent pollution from entering our waterways by serving as a holding place to allow our treatment plants more time to keep up with significant rain events. The addition of Stage I will more than triple the storage capacity for the 3.1 million people it serves across Chicago and 36 suburban communities. It increases the 1.6 billion gallons currently stored in two separate tunnel systems to a combined 5.1 billion gallons of storage that is estimated to provide an average of $114 million per year in flood damage reduction benefits. We thank our project partners at the U.S.
Army Corps of Engineers and for our guests today who have all contributed to this vital project: Sen. Dick Durbin, U.S. Rep. Mike Quigley, U.S. Rep. Dan Lipinski, USEPA Acting Regional Administrator Robert Kaplan, Region 5, U.S. Army Corps of Engineers Chicago District Commander Col. Aaron Reisinger, Illinois EPA Director Alec Messina, McCook Mayor and Cook County Commissioner Jeff Tobolski, Kevin Burke, vice president of the Operating Engineers Local 150, and Jack Darin, director of the Sierra Club Illinois Chapter.


WTTW tour of the McCook Reservoir

MWRD posted about WTTW's coverage of the ribbon cutting ceremony.


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