Guan'gai paishui xuebao (Sep 2022)
Surface Water Quality in Second-phase Zhaokou Yellow River Irrigation District Project
Abstract
【Objective】 The irrigation district at Zhaokou in east Henan province is a project to provide the Yellow River water for irrigation and industrial usage in this region. It is constructed in several phases. The purpose of this paper is to analyze the quality of the water after the second-phase of the project was completed. 【Method】 Water samples were taken from the sections of Guo River and Huiji River in November 2020, January, March, and May 2021 at 21 locations. Their chemical components were analyzed. The pollution index used to evaluate the water quality was calculated using single factor evaluation method, comprehensive pollution index method, and comprehensive water quality labeling index method. 【Result】 The total nitrogen (TN) and total phosphorus (TP) in the water exceeded the standard substantially. From November 2020 to March 2021, water with quality at the Grade V or lower accounted for more than 95%, while in May 2021, the quality of all water reached Grade IV. The results calculated from the comprehensive pollution index method showed that from November 2020 to May 2021, water quality improved from moderate pollution to least or no pollution. It was also found the water quality varied spatially. The results calculated from the comprehensive water quality labeling index method showed that water quality from November 2020 to May 2021 reached Grade IV, the demand for irrigation water quality. 【Conclusion】 The quality of surface water in the second-phase Zhaokou Yellow River Irrigation District project is not optimistic, especially in the dry season. Its TN and TP are the main pollutants. Alleviating non-point source pollution from cropping fields is an important way to improve the water quality.
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