Additional Power Required to Use Smaller Size PVC Irrigation Pipe

Abstract

THE equations for the power required to pump water through PVC pipe have been programmed in BASIC and the results presented graphically as the increase power required to use a smaller size pipe. By using these graphs, designers of irrigation systems can quickly compute pump size and costs of alternative designs. INTRODUCTION The optimum size pipe for an irrigation system depends upon the cost of the pipe, the purchase price of the pump and the pumping costs. Pipe prices usually increase as the size increases, but pump power and pumping costs decrease with increases in pipe diameter. Smaller pipes cost less but require larger pumps to deliver the same flow of water. The increased head necessitated by the smaller pipes not only requires a larger pump but also requires additional operational (pumping) costs. The most economical size pipe (including connecting hardware) is the one which results in a minimum cost over the life of the irrigation system. Fixed costs of pipe and pump must be added to annual operating costs to determine the least cost system.