关键词: 水质特征;时空分异;水质质量指数(WQI);Mann-Kendall非参数检验法;三峡库区;

Abstract: In order to study the tempo-spatial variation of water quality in the Three Gorges Reservoir area since the operation of 175m experimental impoundment, based on monthly water quality monitoring data from 2008 to 2019, the tempo-spatial distribution characteristics of water quality were analyzed by Mann-Kendall non-parametric test method and Water Quality Index (WQI) comprehensive evaluation method. The results showed that the major items exceeding the standard were total phosphorus and permanganate index, the overstandard phenomenon in the upstream was more serious than that in the downstream. The permanganate index and total phosphorus concentration showed a slow decreasing trend from 2008 to 2019. The 2016 was a mutation point of total phosphorus concentration in the main stream, as it had a significant downward trend after 2016 in the mainstream. The WQI of the main and tributary streams in the Three Gorges Reservoir area was on the rise, and the WQI of tributaries was generally lower than that of the main stream, and the WQI in wet season was lower than that in dry and normal season. The research results can provide scientific basis for water environment protection and management in the Three Gorges Reservoir area.

Key words: water quality characteristics; tempo-spatial variation; Water Quality Index (WQI); Mann-Kendall non-parametric test; Three Gorges Reservoir area