Ecological Risk Evaluation of Baihetan Dam Based on Fuzzy Hazard Quotient Model

To evaluate the variation in ecological risk induced by pollutants from construction of Baihetan Dam, largest hydropower station under world, this study proposes a fuzzy hazard quotient (HQ) model designed on basis triangular number (TFN) theory. The HQ uses hazardous TFN to including uncertain observation data, and transition analyze before after dam construction. results show following: (i) ammonia nitrogen (NH3-N) showed marked increasing trend because activity weakened degradation ability water body. chronic NH3-N was classified as “medium” grade its acute “low” grade. (ii) crucial factor for local aquatic ecosystem copper (Cu) key lead (Pb). (iii) After both long-term short-term TFNs Cu were Pb belonged with high certainty, whereas classification had uncertainties. Its vectors upstream {0.000, 0.928, 0.072}, downstream 0.108, 0.892}. (iv) Both risks substantial decreasing trends Dam impounding effect promoted settlement heavy metals sediment. (v) method can be applied perform an evaluation that accounts uncertainties data set, small sample size. Therefore, is effective