Estimation of water consumption in the agricultural area of Iran and evaluation of the results obtained from the WaPOR product with ground data

In this study, Iran's water consumption has been estimated in all provinces of Iran using the actual evapotranspiration product WaPOR which is developed by FAO. To considering the plains which have the main agricultural water consumption of Iran, the amount of water consumed was estimated for every province in the year 2010 to 2016, then the slope of changes in agricultural water consumption was determined for every one of them separately. The volume of water consumption in the agricultural area of Khuzestan, Tehran and Gilan provinces has the highest increasing trend in the period 2010 to 2016, respectively, and in other words, they have a positive slope changes. Hormozgan and Kermanshah provinces also had the largest decrease in the amount of water consumed in the agricultural area. The results of this 7-year statistical period illustrate that water consumption of agricultural and the volume of irrigation has been increasing in Iran since 2013. To evaluate the accuracy of WaPOR product, its values were compared with evapotranspiration from SEBAL algorithm and Lysimeter station statistics in Miandoab plain. The results present that in most areas, the evapotranspiration values of SEBAL algorithm are higher than the WaPOR, which reaches its maximum value by moving to an altitude of 2000 meters. The actual evapotranspiration values of the lysimeter of Tabriz University were in good agreement with the calculated values of the SEBAL algorithm, therefore the volume of water consumed calculated with WaPOR is less than the actual value.