丹江口水源地安全保障区河流水化学特征及影响因素OA

[Objective]The Danjiangkou Water Source Safety Assurance Area is the core zone of the Danjiangkou Reservoir drinking water source protection area.Multiple inflow tributaries directly affect the hydrochemical composition and water quality of the reservoir area.Identifying the controlling factors of river water chemistry is crucial for achieving refined watershed management.[Methods]In July and December 2020,a total of 73 river water samples were systematically collected from the area.Hydrochemical characteristics were analyzed using descriptive statistics,Gibbs diagrams,Piper trilinear diagrams,and ion ratio methods.[Results]The results show that the river water is generally weakly alkaline,with a hydrochemical type of HCO3--Ca2+-Mg2+.Rock weathering is the dominant controlling factor,and spatial differentiation is governed by stratigraphic lithology.The Danjiang River basin is primarily characterized by carbonate rock weathering,while the Hanjiang River basin is influenced by the combined weathering of carbonate and silicate rocks.The Sihe River,Shending River,and Jianghe River in the Hanjiang River basin are significantly affected by industrial activities,whereas the Danjiang River basin is mainly influenced by domestic sewage and agricultural inputs.[Conclusions]This study indicates that the factors influencing the hydrochemical characteristics of different tributaries in the Danjiangkou Water Source Area vary.It provides key hydrogeochemical evidence for understanding the evolutionary mechanisms of the reservoir's water environment and supports the transformation of watershed management from a homogenized approach to a zonal,classified,and precise management model.