A novel hybrid model for water quality prediction based on VMD and IGOA optimized for LSTM

Water quality prediction is vital for solving water pollution and protecting the water environment.In terms of the characteristics of nonlinearity,instability,and randomness of water quality parameters,a short-term water quality prediction model was proposed based on variational mode decomposition(VMD) and improved grasshopper optimization algorithm (IGOA),so as to optimize long short-term memory neural network (LSTM).First,VMD was adopted to decompose the water quality data into a series of relatively stable components,with the aim to reduce the instability of the original data and increase the predictability,then each component was input into the IGOA-LSTM model for prediction.Finally,each component was added to obtain the predicted values.In this study,the monitoring data from Dayangzhou Station and Shengmi Station of the Ganjiang River was used for training and prediction.The experimental results showed that the prediction accuracy of the VMDIGOA-LSTM model proposed was higher than that of the integrated model of Ensemble Empirical Mode Decomposition (EEMD),the integrated model of Complete Ensemble Empirical Mode Decomposition with Adaptive Noise (CEEMDAN),Nonlinear Autoregressive Network with Exogenous Inputs (NARX),Recurrent Neural Network (RNN),as well as other models,showing better performance in short-term prediction.The current study will provide a reliable solution for water quality prediction studies in other areas.