Combined risk assessment method of water environment system.

Accurately assessment of the water environment system combined risk may contribute to the evaluation of the water environment system health status, which has great significance to the safety management of water environment. Markov switching theory (MS), Monte Carlo method (MC) and Copula function were comprehensively applied to the establishment of the method system of water environment system combined risk analysis. Firstly, the water quality series auto-regression model (Al%) was constructed by using the MS. Secondly, the MS-AR and MC were applied to the simulation of water quality series. Thirdly, the Copula function was applied to the construction of multivariate joint distribution of water quality simulation series to calculate the combine risk of the water environment system. Finally, the method system was applied to the Guohe section's water quality combined risk evaluation. The result shows that TP and BOD5 have important effects to the water environment health status of the Guohe, and that there is a positive correlation between TP and BOD5. [ABSTRACT FROM AUTHOR]