Evaluation of wavelet performance via an ANN-based electrical conductivity prediction model

The prediction of water quality parameters plays an important role in water resources and environmental systems. The use of electrical conductivity (EC) as a water quality indicator is one of the important parameters for estimating the amount of mineralization. This study describes the application of artificial neural network (ANN) and wavelet- neural network hybrid (WANN) models to predict the monthly EC of the Asi River at the Demirkpr gauging station, Turkey. In the proposed hybrid WANN model, the discrete wavelet transform (DWT) was linked to the ANN model for EC prediction using a feed-forward back propagation (FFBP) training algorithm. For this purpose, the original time series of monthly EC and discharge (Q) values were decomposed to several sub-time series by DWT, and these sub- time series were then presented to the ANN model as an input dataset to predict the monthly EC. Comparing the values predicted by the models indicated that the performance of the proposed WANN model was better than the conventional ANN model. The correlation of determination (R-2) were 0.949 and 0.381 for the WANN and ANN models, respectively. The results indicate that the peak EC values predicted by theWANN model are closer to the observed values, and this model simulates the hysteresis phenomena at an acceptable level as well.