Integrated Modelling System with Uncertainty Analysis for Reservoir Water Quality Management in a Reclamation River Basin

A developed integrated modelling system with the uncertainty analysis (Monte Carlo simulation and generalized likelihood uncertainty estimation) was used to evaluate the effect of uncertainty sources on long-term water quality and develop river basin management measures to meet the specified water quality criteria based on the predicted probability of occurrence in the reclamation river basin. The results of deterministic integrated modelling system without the uncertainty analysis showed that the Hwaong Reservoir water quality for total phosphorus(T-P) (0.094 mg L-1) in 2022 would meet the reservoir water quality standard (0.1 mg L-1). However, the water quality prediction for theHwaong Reservoir in 2022 using the integrated modelling system with the uncertainty analysis showed that only 28% would meet the T-P water quality standard, indicating that to meet the water quality standard with a 90% level of confidence, further river basin management measures should be applied in addition to the construction of planned wastewater treatment plants and treatment wetlands. The developed integrated modelling system with the uncertainty analysis was demonstrated to be advantageous because it can allow modellers to make useful decisions about whether a river basin management plan can meet specified water quality criteria based on the probability of occurrence.