MWRD: North Shore Channel and Wilmette Pumping Station

(3D Satellite of pumping station)

MWRD posted
A steam shovel in action during excavation for the North Shore Channel near Lake Michigan on May 9, 1908.

MWRD
Wilmette Pumping Station construction 1910. Wilmette Harbor & Lake Michigan in background

Historic Bridges
[One of the original axial-flow pumps.]

Satellite

The building of the Chicago Sanitary & Ship Canal and the dredging and widening of the Main Stem and South Branch of the Chicago River provided enough flow of water from Lake Michigan to flush the sewage and industrial wastes in those bodies of water towards the Gulf of Mexico. But the North Branch did not have a strong enough flow of water to flush it. So the MWRD built the North Shore Channel from where it turns west north to the lake at Wilmette. This provides a strong flow to flush the output of the Lawrence Avenue Pumping Station that is just a couple blocks south of the terminus of the channel.

If you look at how skinny the North Branch is even after it has been damed, it is obvious that they had to dredge and widen the North Branch itself south of its junction with the channel.

To regulate the level of the channel, and consequently the North Branch, a pumping station and lock was completed under Sheridan Road in 1912. For years I have wondered why they built such a long channel to the north rather than a short channel to the east because the level of the lake doesn't change as they go north. When I saw the date of 1912, it occurred to me that the land further from the lake would still be undeveloped. If they dug the channel to the east, they would have had to purchase a lot of developed land along the lake shore.

An MWRD engineer explaining the system to the League of Women Voters in Wilmette.

MWRD posted
A view to the southwest from Wilmette Harbor showing the Wilmette Pumping Station, lock and Sheridan Road Bridge on May 5, 1926.

Looking towards the lake, under Sheridan Road, we see the pumping station on the left and the lock(s) on the right. On the far right is the Baha'i House of Worship.

Screenshot from a MWRD video. Note that, except for the first sentence, the YouTube comment is for another facility.

It was rebuilt in 2012 for $17.5 million. Since they discovered since 1912 that four pumps were not needed, only two pumps were replaced. The other two tunnels are now used just for water flow. They have grates to prevent the Asian Carp from migrating into the lake in case the electric dispersal barrier down by 135th street fails. [SlidePlayer, Slide 4] But I never figured out what is supposed to prevent the carp from going through the locks when the lock gates open. The 30' wide lock was replaced with three diversion tunnels. (Another source said it was three 10' locks, but it looks like that source was wrong.)

Unfortunately, there was a significant rainfall event, and thus river flooding, during the construction.

WGNTV
Flooding causes a breach of the locks under Sheridan Road in Wilmette, overwhelming construction at the rehabilitation of the diversion pumps at the Wilmette Pump Station. (Chris Walker, Chicago Tribune, April 18, 2013)

A video describing the facility after its rebuild.
(Skip to the professional voiceover.) The narration at 5:10 says the gates provide fish migration. This drives me nuts every time I hear it because the purpose has to be to prohibit fish migration, specifically the Asian Carp.