OPTIMAL-DESIGN OF PARALLEL STORM AND FOUL SEWER SYSTEMS

It is usual to have both a storm and a separate foul sewer system for any new housing or industrial development. The optimal design of either the storm or the foul sewer network can be handled efficiently by existing Dynamic Programming methods. However the two systems inevitably interact either because they run parallel in the same construction trench with specified minimum vertical and horizontal clearances, or they cross over each other at particular locations. This paper addresses the problem of optimizing the design of the two networks simultaneously. A rigorous Dynamic Programming method for the optimal design of storm and foul sewers sharing the same trench is presented, together with an outline of a possible approach to the mutual constraints introduced by two networks crossing over each other.