ESTIMATING THE FLUCTUATIONS OF SOIL SALINITY AND WATER DRAINAGE IN UNDERGROUND DRAINAGE AND IRRIGATION NETWORKS OF MIANDUAB USING DRAINMOD 6.0 MODEL

A. Molavi, S. Salimi, S. Darbandi, M. Yousefzadeh

Abstract: Computerized models are used widely in different sciences since they have the capability to reduce the costs and shorten the time required for a scenario to achieve the results of implementation on a system. Drainage networks are usually placed in semiarid lands under irrigation in order to control soil marsh and salinity. Because of the complexity of water travel and salt transfer in soil, simulation models are used to interpret the water management systems performance which may include underground, surface and irrigation drain. One of the models is Drainmod which simulates travel and storage of water in soil. In this research, the efficiency of Drainmod 6.0 model in predicting the soil salinity and water drain of underground drainage system in Mianduab Plain, is evaluated. To do so, an alfalfa field, was selected. The rate of salinity of soil and the drain of the waters extracted from lateral located in it was measured during August 2012. Then, the information required for the model, including meteorological, soil, drainage, irrigation and plant parameters, were collected and the model was implemented, and the obtained results were compared with the measured values. To quantitatively evaluate the performance of the model, the statistical parameters of Root Mean Square Error (RMSE), Mean Absolute Error (MAE) and coefficient of residual mass (CRM) were used. The results showed that the model can simulate the salinity of soil and the waters drain with a high accuracy in the region. The values of RMSE, MAE, CRM obtained for the salinity of water drain were 0.51, -0.24 and 5.82, respectively. And the same values obtained for the soil salinity were 1.06, 0.06, 0.14, respectively.

Keywords: Drainmod 6.0; estimating; Mianduab plain; salinity

Date published: 2017-09-26