Critical points: interactions between on-farm irrigation systems and water distribution network

In this work, a new model useful to analyze interactions between the on-farm irrigation system supplied by critical points and the water supply network management was developed. The model evaluates the impacts of changes in the pressure head and demand simultaneity (number of open hydrants at a given time) on the irrigation system and evaluates emitter discharge and uniformity. It also estimates the potential reductions in crop yield due to decreased emission uniformity. The methodology is applied in the Bembézar Irrigation District (Southern Spain). Results show that the additional cost required for providing maximum pressure to the critical field does not offset the increase in crop yield. Hence, an increment from 91.7 to 92.1 % in yield in the critical field would represent increases in energy consumption from 0.15 to 0.17 kWh m^?3 of water. Also, the unit energy cost could be reduced by up to 0.11 kWh m^?3 without implying significant reductions in crop yield. The importance of a good selection of emitters in the critical fields (fields that are supplied by the critical hydrants) was also evaluated.