Comparative Study of Design of Sewer Line Using Hazen-Williams and Manning Equations

The design of gravity sewer and sewer line can be done using Hazen-Williams and Manning equations. The selection of pipe diameter depends upon sewer pipe materials, and minimum size, minimum and maximum velocities and slope; and for economical design, all these factors need to be considered. This paper deals with the optimal design of sewer line using Hazen-Williams and Manning equations as hydraulic model, and dynamic programming as optimization tool. The feasible set of diameter can be obtained considering the relative depth ratio, maximum and minimum velocities. The head loss is calculated for each diameter and the same is rounded off to the next higher value at an increment of 5 mm. The optimal solutions obtained using both the equations are presented in this paper.