Comprehensive risk assessment of algae and shellfish in the middle route of South-to-North Water Diversion Project.

Abstract

Since the main canal of the middle route of South-to-North Water Diversion Project was put into operation, the species, quantity, and biomass of algae and shellfish have responded quickly to the environment, and a single dominant species has appeared in the community, demonstrating the remarkably abnormal proliferation property of algae and shellfish. In order to evaluate the safety risk of abnormal proliferation of algae and shellfish in the middle route and realize dynamic analysis of all kinds of influencing factors, a comprehensive risk evaluation system of algae and shellfish in the middle route of South-to-North Water Diversion Project based on comprehensive weighting and four-element connection number was constructed by integrating the analytic hierarchy process (AHP) and the weight assignment theory of criteria importance through intercriteria (CRITIC). The system consists of 21 evaluation indexes selected from risk factors and carriers. Taking Henan section in the middle route as an example, comprehensive risk evaluation system of algae and shellfish in the middle route of South-to-North Water Diversion Project was applied to calculate the partial connection number of each order and obtain the risk development trend of each indicator. The results showed that algae and shellfish in the middle route were in a very safe state at the safety risk level of level I. Finally, reasonable measures to reduce the risks facing algae and shellfish in the middle route of South-to-North Water Diversion Project are given, which effectively make up the deficiency of existing evaluation methods.