Simulation of Drainage Water Salinity and Discharge of Subsurface Drain Using System Dynamics Approach; Case Study in Sugar Cane Research Center of Amir Kabir

Quality and quantity of drainage water in saline lands, which require primary leaching is continuously changing from the beginning of irrigation and drainage network operation before reaching a more or less equilibrium state. The time to reach a state of equilibrium in areas with saline groundwater may take several years. Therefore in this paper, the system dynamics technique that is one of the object oriented approach was used to simulate farms of irrigation and drainage network, and determine model performance to simulate the drainage water salinity and discharge of subsurface drains. To validate the results of the model, data collected in the 2004 and 2005 cropping years from ARC2, ARC4, ARC6 and ARC8 farms was used in the research area of ​​Sugar Center Research Center (Amir Kabir Agro Industrial Development Unit of Sugarcane Development Company, Khuzestan Province). To statistical analysis and calculating, the root mean square error (RMSE), standard error (SE) and correlation coefficient (R2), were used. In this regard, the RMSE statistical index for drainage discharge of ARC2, ARC4, ARC6 and ARC8 farms were 6639, 8546, 7950 and 8207 m3/day respectively. Also, the RMSE for drainage water salinity of the farms were 2.25, 4.86, 2.04 and 7.98 dS/m respectively. The results showed that the model is capable of simulating the drainage outflow and its salinity in saline and shallow water table region