title: Influences of anthropogenic activities and topography on water quality in the highly regulated Huai River basin, China.
abstract: Our study analyzed the spatio-temporal trends of four major water quality parameters (i.e., dissolved oxygen (DO), ammonium nitrogen (NH3-N), total phosphorus (TP) and permanganate index (CODMn)) at 17 monitoring stations in one of the most polluted large river basins, Huai River Basin, in China during 2005 to 2014. More concerns were emphasized on the attributions, e.g., anthropogenic actives (land cover, pollution load, water temperature, and regulated flow) and natural factors (topography) to the changes in the water quality. The seasonal Mann-Kendall test indicated that water quality conditions were significantly improved during the study period. The results given by the Moran's I methods demonstrated that NH3-N and CODMnexisted a weak and moderate positive spatial autocorrelation. Two cluster centers of significant high concentrations can be detected for DO and TP at the Mengcheng and Huaidian station, respectively, while four cluster centers of significant low concentrations for DO at Wangjiaba and Huaidian station in the 2010s. Multiple linear regression analysis suggested that water temperature, regulated flow, and load of water quality could significantly influence the water quality variations. Additionally, urban land cover was the primary predictor for NH3-N and CODMnat large scale. The predictive ability of regression models for NH3-N and CODMndeclined as the scale decreases or the period ranges from the 2000s to the 2010s. Topography variables of elevation and slope, which can be treated as the important explanatory variables, exhibited positive and negative correlations to NH3-N and CODMn, respectively. This research can help us identify the water quality variations from the scale-process interactions and provide a scientific basis for comprehensive water quality management and decision making in the Huai River Basin and also other river basins over the world.
authors: State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan, 430072, China. Weishi1208@163.com.|Hubei Provincial Collaborative Innovation center for Water Resources Security, Wuhan, 430072, China. Weishi1208@163.com.|The Research Institute for Water Security, Wuhan University, Wuhan, 430072, China. Weishi1208@163.com.
authors: Wei
authors: W
authors: Shi
authors: State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan, 430072, China. xiajun666@whu.edu.cn.|Hubei Provincial Collaborative Innovation center for Water Resources Security, Wuhan, 430072, China. xiajun666@whu.edu.cn.|The Research Institute for Water Security, Wuhan University, Wuhan, 430072, China. xiajun666@whu.edu.cn.
authors: Jun
authors: J
authors: Xia
authors: State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan, 430072, China.|Hubei Provincial Collaborative Innovation center for Water Resources Security, Wuhan, 430072, China.|The Research Institute for Water Security, Wuhan University, Wuhan, 430072, China.
authors: Xiang
authors: X
authors: Zhang
mesh_terms: D002681:China; D004784:Environmental Monitoring; D005843:Geography; D016014:Linear Models; D045483:Rivers / Q000737:chemistry*; D012621:Seasons; D062206:Spatial Analysis; D014874:Water Pollutants, Chemical / Q000032:analysis*; D060753:Water Quality
chemical_list: D014874:Water Pollutants, Chemical
keywords: Land cover; Regression analysis; Regulated river basin; Scale; Spatial association; Topography; Water quality