Assessment of the surface water quality ranking in Mudan River using multivariate statistical techniques

The present research deals with the important issue of assessing surface water quality ranking by combining the use of two advanced multivariate statistical techniques: Kohonen's self-organizing maps (SOM) and the Hasse diagram technique (HDT). The object of the study is the Mudan River of Mudanjiang city region, China. Samples were collected on a regular monthly basis in 2007–2011 from all sampling sites along the river, involving six major water quality parameters. The grouping of water parameters and the clustering of sampling events by the use of SOM has helped in their pre-processing for application of the HDT. The HDT orders clusters according to the pre-clustered water sampling events. The water quality was ranked against norms established by the Ministry of Environmental Protection of the People's Republic of China in order to assess in detail the water quality of the whole river system. The resulting map of the spatial and temporal changes in the water quality at each sampling site was specifically described by ArcGIS.