Ecological environment health assessment of lake water ecosystem system based on simulated annealing-projection pursuit: A case study of plateau lake

A lake ecological environment health assessment index system is constructed based on DPSR (Driving forces-Pressure-State-Responses) framework. The simulated annealing projection pursuit (SA-PP) algorithm, which can analyze high-dimensional data, is introduced and provides a new way for lake ecological environment health evaluation and decision-making. Qionghai, a typical plateau lake in Sichuan, China, is taken as an example to introduce the application of this assessment system. The results suggest the water ecological environment of Qionghai basin is in a relatively healthy state from 2017 to 2020. The state subsystem has the largest weight, and the important influencing factors affecting the health of lake water ecological environment are the water environment characteristics, ecological characteristics and pressure subsystem in the State subsystem. Zooplankton Simpson diversity index, chlorophyll a, NH3-N and total nitrogen are the main influencing factors of lake ecosystem health in the lake ecosystem health system. The restriction factor of the pressure subsystem is per capita daily domestic water consumption. Therefore, improving water quality and controlling water consumption intensity become important factors to improve the health of water resources and water environment in Qionghai basin. This study provides a new way for lake ecological environment health evaluation and decision-making.