During storms and floods, when the trunk sewers fill to bursting, the excess water spills into the smaller overflow sewers, which, acting like safety valves, run out into the Thames.
And in many cities, a mild thunder storm is enough to overflow sewers and release sewage into fresh water supplies.
The decisions and measures rather depend on the impact, not on the precipitation itself, but on flooded basements, overflowed streets and overflowing sewer systems that cause the disruption to the organizational routines.
Today most raw sewage contributions to the Great Lakes are inadvertent, and they most often come from overflowing sewer systems during storms.
The health implications of blocked and overflowing sewers are obvious.
There is a long record of complaints about overflowing sewers in the borough.
He also cited dontflush.me, a citizen-designed web tool to advise New York residents about overflowing sewers.
Overflowing sewers were dealt with in places such as Bristol in the late 1990s; prices have been higher outside the capital as a result.
(There was some logic in it. Polio, an intestinal virus, peaks in summer, and is more common in cities with overflowing sewers than in rural areas with outhouses).
The new plan will include money to restore the city's rotting and overflowing sewers, said local officials who had been briefed on aspects of the plan.
