ABSTRACT
USING the information obtained from the earlier surveys, and working on a map of l :2500 or 1:10 000 scale, as is relevant, it is now possible to set out lines of possible sewers for either the surface water run-off or for foul sewerage. The possible points of discharge (e.g. watercourses for surface water sewers, and treatment works for foul sewers) will set the overall pattern of the system of sewers. The sewers themselves should then follow the fall of the surface of the ground as far as possible, as this will reduce depths of excavation or, alternatively, will reduce pumping costs to a minimum. Pumping stations and rising mains are considered in Chapters 14 and 15.
