mazandaran plain

Groundwater resources along with surface water supply the needs for municipal, industrial and agriculture uses, and their quantity and quality should be investigated. Salinity is one of the most important parameters in assessing the quality of groundwater. In this study, application of artificial neural networks and Bayesian network in predicting the electrical conductivity in 8 observation wells in Mazandaran plain was investigated. For this purpose, hydrogen carbonate, chloride, sulfate, calcium and magnesium were selected as input and output parameters for electrical conductivity at monthly a scale during 2003-2013. The criteria of correlation coefficient, mean absolute error and Nash Sutcliff coefficient were used to evaluate the performance of the model. The results showed that artificial neural network model has the highest correlation coefficient (0.989), the lowest mean absolute error (0.019 ds/m) and the highest standard of Nash Sutcliffe (0.970) ranked the first priority in the validation phase. The results indicate acceptable capability of artificial neural network models to estimate the electrical conductivity of groundwater.

Rate of water hardness is an important factor in hydrogeology, particularly in groundwater quality researches. In recent decades, the artificial intelligence systems such as artificial neural networks have many applications in various sciences, including management of water resources. In this study, estimated rate of groundwater hardness in Mazandaran plain, using Gene expression programming have been studied and the results is compared with other intelligent methods such as artificial neural network and Anfis. For this purpose the hydrogen carbonate, chloride, sulfate, magnesium and calcium monthly time scale of the period (1994-2014) was selected as inputs and water hardness as output. Standard deviation of the correlation coefficient, root mean square error, and coefficient of Nash Sutcliff were used to assess various methods. The results showed that Gene expression programming model has the maximum correlation coefficient 0.960, minimum root mean square error 0.112, mean absolute error 0.171 coefficient of Nash Sutcliff 0.880 was in the verification phase. In overall, the results showed that the Gene expression programming model has high performance in estimating some maximum and intermediate values of groundwater hardness.