Connection number based assessment model for watershed water security

On the basis of theoretical analysis, expert consultant and on-site investigation, an index system for assessing the water security of watershed under uncertain environment was established. The accelerating genetic algorithm based fuzzy analytic hierarchy process was used to screen the index system and to determine the weights of both indexes and subsystems of water security assessment system. The index connection numbers, subsystem connection numbers and sample connection numbers between assessed samples and evaluation grading standards were established by using set pair analysis method. Then, a. connection number based quantitative assessment model for watershed water security, named connection number assessment model (CN-AM), was established. The application of this model to assess the water security of Chaohu Lake watershed shows that the joint application of judgment method based on principle of equally sharing connection coefficient with method according to confidence criterion of attribute mathematics in CN-AM can improve the reliability of the assessment result. The water security in Chaohu Lake watershed is in a critical security state, the economy, science and technology development level must be further heightened, the water saving technology must be popularized, the urbanization process must be accelerated and the population growth must be controlled in order to heighten the safeguard degree of the watershed water security.