|MWRD from DNAi*/nfo|
The Calumet TARP Pumping Station is the lowest point of the TARP System and lowest point in Chicago.
TARP stands for "Tunnel and Reservoir Plan," which according to MWRD was adopted in 1972 to "comply with federal and state water quality standards in the 375 square miles combined sewer area consisting of Chicago and 51 suburbs." It is more commonly known as the Deep Tunnel project. [DNAinfo]My wife and I toured the Mainstream Pumping Station before it went online. We were also able to walk into the tunnel that feeds it. After it went online, I'm sure they keep the tunnel part sealed off since it is a BIG sewer. That station was also was below 300' because the tunnels are deep so that they travel through solid sedimentary rock their whole distance. It is easier to use a Tunnel Boring Machine in rock rather than in sand or clay. And sedimentary rock is relatively soft compared to igneous or metamorphic rock.
MWRD posted four photos with the comment:
We welcomed the American Society of Civil Engineers (ASCE) Illinois Section today for a tour of the MWRD's Mainstream Pumping Station, visiting 300 feet below Lake Michigan to see the massive pumps that keep water flowing throughout Chicago and keeping the region dry. The circle, 33 feet in diameter, where the group passed through, represents the dimensions of the MWRD's Tunnel and Reservoir Plan's Deep Tunnel. The engineers then visited the McCook Reservoir from above the east rim. The reservoir is currently under construction and, when completed, it will have a total capacity of 10 billion gallons, providing more than $114 million per year in flood damage reduction benefits to 3.1 million people in 37 communities. The reservoir will be the largest of its kind once complete, large enough to contain 11 Soldier Fields. The first phase of the reservoir is due to be complete by the end of 2017.[But none of the pictures show any pumps or electric motors. Bummer.]