>twelve football stadiums stacked together

I understand that football stadium play area is standard, but how do you measure height? Is it a foul to kick the ball too high in the air? The play area, I assume isn't limited vertically.

It says "volume of twelve stadiums" so maybe by treating an entire stadium as a giant bowl up to the top of the seating? But who knows what stadium is the reference stadium - that's not a consistent thing like the size of a football field.

Excellent point. I just wish they'd use the correct SI unit for this kind of thing - "libraries of congress".

DC’s Clean Rivers Project is building 4 long tunnels to act as a buffer for the old combined sewer system. Some of the tunnels are complete and already functioning. Previously large storms would cause the sewers to overflow into the Potomac and Anacostia rivers. The EPA wound up suing DC and the Clean Rivers Project is the result. The new tunnels have already had a huge effect.

https://www.dcwater.com/cleanrivers

Massive side not - I have no idea why you guys insist on using football stadiums and football fields as a unit of measurement, what gives?

Just a handy visualization - easier to conceptualize than "12.9 billion gallons."

> 12.9 billion gallons.

You mean 39600 acre-feet? :)

Just yesterday, a street downtown buckled from the pressure of stormwater running underneath it.

1. https://wgntv.com/2019/05/01/video-captures-street-buckle-in...

Probably wouldn't want to be there today. ;) (Lots of rain, I think the tunnels are full.)

A couple years ago we stopped by the Lincoln Oasis (rest stop consisting of a bridge over the interstate that carried restaurants and similar instead of traffic.) As I was heading back to my car, I heard a loud whooshing noise and saw what looked like a geyser next to the ramp to get back on to the highway. I walked over to inspect and found a large grate fenced off and signed Chicago Water Reclamation (or something similar.) We had had a lot of rain the night before and apparently this was a vent to release air as the tunnel filled. The location is very near one of the quarries that is used to hold excess runoff.

Interestingly the recent late season rain has the Deep Tunnel almost full. [1] Two of the three main reservoirs are already at capacity, and the the last one is getting there.

BTW they do offer tours of the pumping stations, but not the tunnels [2]

[1] https://chicago.cbslocal.com/2019/05/01/heavy-rain-flooding-... [2] https://www.mwrd.org/irj/portal/anonymous/tourinf

Milwaukee, WI is building a Deep Tunnel project as well. It's certainly not as large as Chicago's, but the need is similar (city built on swampland). They are, after all, neighboring cities on Lake Michigan.

https://www.mmsd.com/what-we-do/wastewater-treatment/deep-tu...

https://www.scientificamerican.com/article/sewer-diving-milw...