China's Main River Water Quality Structure Analysis

Abstract

This article analyses five river basins' water qualities: the Song Hai Liao river basin, the Huaihe river basin, the Yellow river basin, the Yangtze river basin, and the pearl river basin. We consider four water pollution indicators: PH, DO, CODMn, and NH3-N. First, the result of single factor analysis of variance indicates that the four water pollution indicators among the river basins all have significant differences. Then, the result of the multi-class distance classification method indicates that under the condition of the water quality is divided into 6 classes, 4 indicators have the correct rate of 63.64%, and under the condition of the water quality is divided into 5 types, 4 indicators have the correct rate of 78.79%. After that, by drawing a pie chart of the river basins' water quality distribution, we obtain the ranking of the river basins pollution levels: the Yellow River basin > the Huaihe river basin > the Song Hai Liao river basin > the pearl river basin > the Yangtze river basin. Finally, by collecting 2004, 2007, 2010, 2013 four years data, we analyze the changes of the river basins' water quality structure from year to year, and give some suggestions. Keywords—river basin, water quality structure, single factor analysis of variance, Kruskal-Wallis rank sum test, multiple t test, multi-class distance classification method