Surface Water Quality Evaluation and Pollution Characteristics Analysis in Xinyang

This paper aims at evaluating the surface water quality and analyzing the characteristics of the surface water pollution in Xinyang. Based on the remote sensing image in 2005, DEM and surface water quality dataset during 2001-2007, the evaluation and analysis was made by using ArcGIS, SWAT model, equal standard pollution load method and a universal index formula of water quality evaluation suited to multi-parameter based on the genetic algorithm. The results showed that during 2001-2007 water quality of sites influenced only by nonpoint source pollution was much better than that of sites influenced by both point and nonpoint source pollution, and the main pollutants were NH₃-N, COD, TP. The point source pollution in the study area was alleviated during the seven years while TN and COD were the major pollutants. For nonpoint source pollution only agricultural fertilizer pollution was analyzed owing to lack of data, and extent of fertilizer pollution was roughly represented by the ratio of area of arable land to total land area. Finally it was found that water pollution characteristics of monitoring stations behaved differently according to their different pollution sources.