Performance of Stationary Gun Irrigation Systems

The field performance of stationary giant gun irrigation systems is evaluated from the results of 70 distribution tests conducted in the interior of British Columbia, Canada. Three measures of field performance are quantitatively evaluated including maximum application rate, evaporation and spray loss and distribution uniformity. Maximum application rate is found to be a function of average wind speed in the principal wind direction. Evaporation and spray losses were dependent on climatic and operating conditions, primarily the atmospheric vapor density deficit and the average wind speed. The uniformity of application is strongly influenced by both the gun spacing and the average wind speed. The influence of operating variables such as nozzle size and pressure are accounted for in the parameters used to nondimensionalize these relationships. The equations representing these findings are derived using multiple regression and are presented algebraically. Measured values are plotted against predicted values to give a visual impression of scatter in the data. The utility of the relationships in designing and operating giant gun systems is illustrated.