
Inside Seattle's West Point Treatment Plant Disaster - optimiz3
https://projects.seattletimes.com/2017/west-point/
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PhantomGremlin
A large part of the problem is because of "a combination of raw sewage and
stormwater". That is what's called a "combined sewer".[1] It's an insane thing
to have in areas like Seattle and Portland where it rains a lot. It means
you're periodically dealing with massive amounts of water.

I live in a newer community near Portland and our stormwater drains are
independent of our sanitary sewers. Thankfully.

[1]
[https://en.wikipedia.org/wiki/Combined_sewer](https://en.wikipedia.org/wiki/Combined_sewer)

~~~
brudgers
Combined sewers are generally syptom of aged infrastructure. For many years
standard practice has been to separate storm and sewer systems -- in part
because the cost of treating sewage is roughly proportional to the volume of
water passing through the system.

Going further, stormwater systems are also a sign of obsolescent approaches to
infrastructure. Contemporary practice and progressive land use regulations
require development generated additional runoff to be mitigated on-site to
maintain pre-development flow rates at a development site's edges.

~~~
burfog
Stormwater systems are superior. On-site mitigation supports mosquitoes and
lets automotive fluids seep into the soil. On-site is only preferred due to
cost, particularly because of who is paying.

