Overflows
These are stormwater flows that escape from a pipe system or a detention storage for one of these reasons:
flows reaching a pit cannot be accepted by the pit inlet, and flow away as bypass flow,
flows are forced to upwell out of a pit because the downstream pipe has insufficient flow capacity,
flows cannot enter an open channel because it is completely filled,
a detention storage becomes completely full.
Overflows may be due to a combination of effects. In DRAINS they are directed along overflow routes to downstream pits or out of the system altogether.
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