Uncertainty Analysis of Pressurized Irrigation Impact on Urmia Lake Basin Outflow, Case Study: Zarinehrud Basin, Iran

Pressurized irrigation is one of the proposed plans to resolve the Urmia lake crisis. The effects of such plan can be assessed using the hydrological simulation. But different agricultural management approaches and uncertainty in the model inputs lead to complexity in the basin modeling which in turn increases the uncertainty of model outputs. The main purpose of this study is to determine the effect of the pressurized irrigation on Zarinehrud basin as the largest sub-basin of the Urmia Lake basin. For this purpose, by determining the probable scenarios of water demand, the impact of these scenarios on the basin hydrological components were simulated with SWAT model. Then by combining the results of the scenarios, the uncertainty bounds of the hydrological components were estimated using Bayesian model averaging (BMA). The results showed that the annual average of upper and lower bound of the basin outflow will be 1391 and 1316 MCM. Also irrigation efficiency in the field scale and in the basin scale varied between 40-47 and 78-81 percent, respectively. In case the pressurized irrigation is applied, the annual average of upper and lower bound of the basin outflow will be 1322 and 1364 MCM which did not show a significant change compared to the current conditions.