SIRIAS: a simulation model for sprinkler irrigation - I. Description of model

Uniformity of distribution in irrigation systems plays an important role in the optimum use of irrigation water, with direct repercussions on water-us e efficiency and production. To evaluate the effects of the wind on sprinkl er water uniformity, it is necessary to measure infield water distribution under different wind conditions and then calculate the parameters that defi ne water distribution. This paper perfects the SIRIAS simulation model for sprinkler systems, which can be used to design new irrigation installations or to improve existing ones. Using ballistic theory to simulate the trajec tory of drops discharged by the sprinkler, the model obtains wind-distorted water distribution, with a new formulation for the air drag coefficient. I t takes into account three options to distribute the evaporation and drift losses in the irrigation process. SIRIAS software has been programmed using Delphi language for Windows 95, 98 and NT.