Design of Pipe Distribution Systems for Sprinkler Projects

A project type sprinkler system comprises a central pressure-producing device and high pressure mains radiating to farm delivery locations. The minimum cost distribution system will deliver just enough water to meet peak demands with sprinklers operating almost continuously. An equation is developed to determine cost differential between this minimum capacity system and one using large pipe to allow part-time sprinkling. A method for economic sizing of pipe in a gravity system is developed and its use illustrated. An economic sizing method for pump discharge lines with lateral turnouts is also developed. Use of graduated size pumps is recommended to provide greatest flexibility in operation with a reasonable number of units. Fluctuation of operating pressures at farm delivery caused by changing demand during the irrigation season remains a problem in the use of these systems.