Study On Evaluation Method Of Water Resources Carrying Capacity Based On Projection Pursuit

Urban population expansion, rapid economic development, making the increasing stress of urban water, while the aquatic environment deteriorating, which Seriously threaten the urban sustainable development and virtuous cycle of water resources.Regional water resources carrying capacity has been a research hotspot at home and abroad, especially research on the evaluation methods and evaluation index system.Establish a scientific and reasonable evaluation index system and evaluation method of water resources carrying capacity, has important theoretical significance and practical value, for clearly understanding the status of regional water resources carrying capacity, determining key factors influencing water resources capacity,formulating a scientific and reasonable plan of regional economic development and water resources utilization, promoting the coordinated development between socioeconomic system and water resources system.Water resources carrying capacity research involves water resources, society,economy and ecology, a mutual coupling complex system, with openness and uncertainty, so the objectivity and reliability of the evaluation results are not easy to grasp. Considering the ambiguity and uncertainty of the evaluation index, and the difficulty to determine weight for traditional evaluation method, we use Projection Pursuit technique to water resources carrying capacity evaluation, for it can automatically realize screening index and determining the index weight, and take four municipalities for example. The main contents and results are as follows:First of all, research progress of water resources carrying capacity evaluation index system and evaluation methods at home and abroad were reviewed, and the problems existing in the current index system and evaluation methods were analyzed.Secondly, based on the connotation, evaluation purposes, and related theory of water resources carrying capacity, we analyzed main factors affecting water resources carrying capacity, proposed evaluation system design principles, and established a water resources carrying capacity evaluation system with universality as well as evaluation criteria and its rating.Finally, on the basis of above index system, we analyzed the applicability of Projection Pursuit technology used to water resources carrying capacity evaluation,and established Projection Pursuit Grade Evaluation Model, and applied it to the empirical research of four municipalities. Genetic algorithm was used to solve the model and get the best projection vector, then according to the projection characteristic value of each index, we determined the ‘advantage index' and ‘short board index' influencing water resources carrying capacity from city to city. The evaluation results were comprehensively analyzed, and measures to improve water resources carrying capacity were put forward from opening source, structural adjustment, technology, management, ecological security and so on.The evaluation results show that: the water resources carrying capacity of the four municipalities directly under the central government in the year of 2012 were all belong to the third level, while Shanghai was close to the second level, Tianjin was close to the fourth level, water resources carrying capacity in the order of descending was followed Shanghai>Chongqing>Beijing>Tianjin. Compared with other comprehensive evaluation methods, this method has higher stability and simplicity,and can avoid the subjectivity and uncertainty in determining index weight. At the same time, it can be used to screening index and optimize index system, the evaluation results have higher precision and discrimination, can be widely used in various evaluation problem.