Application of Grey Relation Analysis Method in Water Quality Evaluation of Li River for South-to-north Water Diversion Project

The water quality of Li River is an important consideration when selecting the route of Gate No.10 of auxiliary project in Henan provincial intake area of South-to-north Water Diversion Middle Route.Different water quality evaluation methods will obtain different evaluation results.Water Environmental System is a typical and fuzzy gray system,while gray relation analysis method is simple and physically univocal.Therefore,an gray relation analysis method based on distance from point to area is adopted to evaluate the water quality in Li River based on the Monitoring data of 2008-2009.The comparison with existing varies of methods shows that this method is available and the result can provide scientific reference for the section of the route of Gate No.10.