Parisian Sewer & Subway System Questions

[usclaireforce]

Hi! I'm a software developer working on an app about Parisian sewers and subway systems. I'm not here to promote anything, I just wanted to do some research and ask experts about topics outside my range of knowledge.

When building underground subway systems for large urban areas, are subways generally constructed above preexisting sewer systems, below, or at about the same level? If so, why? I've looked around for data regarding the depth of the Paris Metro, and at it's deepest it's 36 km, but I haven't found any conclusive data about the depth of Parisian sewer systems.

Thank you for your time and help.

 

[bimr]

There will be a historical, topographic, and geotechnical considerations that are unique to each city, so it is not possible to generalize.

Typically, sewers are shallow. Interceptor sewers which are main trunkline sewers are deeper. The topography will play a major part in deciding what depth the sewer needs to be.

 

[rconner]

[was just curious did you really mean "36 km"?]

 

[bimr]

Here is a link to the London interceptor.

http://www.mswmag.com/online_exclus...st ‘Super Sewer’ MORE&utm_campaign=160209_MSW