a generic water encapsulation technique [Re: floods]

Fri Apr 11 01:29:03 UTC 1997

Kent W. England wrote:
> 
> We could also multiplex the rain water with the sewage water in a
> multi-mode drain system. Internet drain specialists tend to take religious
> points of view on whether we should have separate drain systems, should
> combine them, or outlaw one in favor of the other. But, clearly,
> encapsulation is the favored approach.
>

The multiplexed drain system will never work.  Sewage water we know
to be a fairly constant flow over time,  and in fact sanitary engineers 
refer to it as having a Constant Flow Rate.  Storm water, on the other
hand, is
very bursty in nature, and sanitary engineers describe that as Variable 
Flow Rate.  In the old days they tried combining drain systems, sharing
the resources between the CFR water and the VFR water, and called the
result AFR (or 
available flow rate).  AFR had one weakness, however: it relied upon a
phenomena called precipitation shaping to keep the VFR storm water from
interfering with the CFR sewage water.  As the clouds and the ground
didn't 
have enough buffering to do proper precipitation shaping, the result was
a drain system which periodically suffered massive congestion, and all 
users were equally unhappy.

-peter