Assessment and development of an optical technology for continuous suspended sediment measurement in aquatic environments

Document Type : Research Article

Authors

1 Assistant Professor, Department of Natural Resources and Environment, Faculty of Agriculture, Payame Noor University, Tehran, Iran.

2 Assistant Professor, Department of Hydraulic Engineering and Hydro-Environment, Water Research Institute, Tehran, Iran

3 Full Professor, Faculty of Natural Resources and Environment, Ferdowsi University of Mashhsd. Iran

Abstract

The aim of this research is to construct and validate an optical sensor with a multi-beam ratio technology and artificial intelligence-based modelling (MLP & SVR) for suspended sediment measuring. After implementation of the new technology, the performance of the device was evaluated in two stages including calibration and validation. To attain this, various experimental tests carried out in the hydraulic laboratory of Water Research Institute of the Ministry of Energy. Reference turbidity meter and total suspended solids (TSS) were used to test the performance of the OBS technology. In calibration stage, 70% of TSS data were used and the remaining 30% of data were used to validate optical technology. The plotted calibration curves show a very good correlation between the optical voltage recorded by the sensors and the suspended sediment concentration. Also, SVR & MLP models were employed to improv results of suspended load prediction. The performance of optical device and also optical device with intelligence models were evaluated through four statistical indices namely, Mean Absolute Percentage Error (MAPE), Root mean square Error (RMSE), Nash–Sutcliffe coefficient (NSE), correlation coefficient (R) and coefficient of determination (R2). The results of this stage showed that the intelligence modelling could result in improvements of suspended load reported by optical technology. The best improvements obtained by MLP-optical technology. The results showed that values of validation indicators for MLP model are equal to 0.023, 7.608, 0.99, 0.99 and 0.99 respectively, which indicates the proper performance of the technology.

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