The impact of transition from flood to sprinkler irrigation on water district consumption

The ‘Irrivol’ method for calculating the water volume required in an irrigation district is expanded by correlating it with soils map. The resulting water volume maps are used to analyze a proposed change from controlled flooding irrigation to sprinkler irrigation. The soil map is then used to evaluate the productive potential of the land in order to select the soils for sprinkler irrigation, to extrapolate field measurements of flood irrigation efficiency, and to account for the reuse of the non-consumptively applied water to higher landforms. The soil map is crossed with four years of remote-sensed crop maps. For each year the calculated water volumes applied currently and the volumes that would have been applied using sprinkler irrigation were compared. Our calculations overestimated the measured supply by 10% for two years, with marginal differences for the other two. With the present crops, sprinkler irrigation would have saved about 7% of the water supply. Most likely this will not result in real water saving, but in a higher beneficial use of water.