Development of Indexed-Position Sprinklers and System Design for Year-Round Irrigation

Abstract

ABSTRACT DESIGNING an efficient and effective irrigation system for land application of treated municipal sewage effluent presents a challenge to the designer, especially when requirements for operation at temperatures from -30 to +40 C, for management in both wooded and cropped areas, and for 24-h per day, year-round operation are included. Details are presented on the design and operation of a 26 ha solid-set spray ir-rigation installation which has been operated on an ex-perimental basis since 1963. In addition to general infor-mation on design, specific details on research to develop reliable sprinklers with good distribution patterns for year-round operation are presented. Also presented are practical suggestions and insight into some of the equip-ment and operational problems which should be an-ticipated in future designs of such systems. Detailed development work was necessary for year-round operation since the misting action of most com-merical sprinklers leads to ice buildup on the turning mechanisms and prevents rotation of the sprinklers, causing unsatisfactory operation during freezing temperatures. The fine spray of some other commercial sprinklers leads to a smooth ice layer with little subse-quent penetration of the effluent, making their operation unsatisfactory also. Efforts in this research were directed in the area of indexed-positioning to improve penetration and reduce runoff while maintaining good uniformity during winter operation. Three indexed-positioning sprinkler types were developed and tested. They were compared with two commercial and one previously developed experimental non-indexing sprinklers.