Quality of local control for simple sewer networks

Abstract

Combined sewer networks, where both foul water and storm
water are transported through the same system, tend to develop into complex
networks due to expansion of towns and villages. The transport capacity of
these systems is always limited, so occasional controlled spills into surface
water, combined sewer overflows (CSO), are part of the normal operating
procedure. Occasionally the ideas and rules present in the original design are
not respected when the system is extended to cover a larger area. One way to
deal with this problem is to implement central control. Another is to add pipes
and hardware to bring the extended system into line with the original rules and
ideas.We show that for a design rule often followed in the Netherlands, local
control does quite well as long as the rule is respected and there are no large
variations in precipitation intensity over the area covered by the system.