Author(s): Wei Huang; Chenguang Xiang; Zhuowei Wang; Huaidong Zhou
Linked Author(s): Wei Po Huang
Keywords: Eutrophication risk Ecological water supply project Copula Water quantity and TP concentration
Abstract: It is very important to evaluate the eutrophication risk of the receiving lake for making a scientific water replenishment plan. However, the significant impact of water replenishment project on the process of lake water quantity and quality makes the evaluation of eutrophication more complicated. In this study, a new perspective is put forward to evaluate the eutrophication risk of lakes by considering the joint action of water quantity and water quality (TP concentration). By applying nonparametric kernel estimation in Copula model, the marginal distribution is directly fitted according to the original data, and the accuracy of marginal probability distribution is improved. In addition, Gaussian Copula model among five candidate Copula models is selected, and the joint probability distribution function between the amount of water supplement and TP concentration is established. The eutrophication risk of the lake was then assessed based on ten replenishment scenarios covering six water amounts and four time periods. The results showed as follows: 1) Water replenishment significantly reduced the eutrophication risk of Caohai lake; 2) With the increase of water replenishment amount, the probability of exceeding the standard of TP concentration decreases, and the probability is 0.44 when the ecological water requirement is reached; 3) The probability of water quality exceeding the standard (0.49) is obviously lower than other scenarios when water is replenished in dry season. These findings are helpful for eutrophication risk assessment and adaptive management of water replenishment projects in plateau lakes.
Year: 2025