College of Environmental and Natural Resources, Zhejiang University, Hangzhou, 310058, People's Republic of China.
Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, Zhejiang University, Hangzhou, 310058, China.
Environ Sci Pollut Res Int. 2021 Mar;28(9):11129-11141. doi: 10.1007/s11356-020-11352-4. Epub 2020 Oct 28.
Understanding the effect of landscape characteristics on water quality can provide insight into mitigating water quality impairment. However, there is no consensus about the key controlling factors influencing water quality. This paper examined the combined effects of land use and topography on water quality across multi-scale, and identified the key controlling factors determining water quality variation in the headwater watershed of the Hengxi reservoir in Eastern China. Water quality impairment (WQI), expressed as a composite variable, was established to measure the overall water quality. We used the partial least squares (PLSR) method to explore the combination of landscape metrics and identify the key controlling factors. Results showed that the optimal PLSR model at 50-m, 100-m, and 150-m buffer scales and catchment scale explained 77%, 63%, 60%, and 56% of variability in WQI, respectively. At catchment scale, patch density, the percentage of paddy field, and hypsometric integral were the key controlling factors impacting water quality. At buffer scales, the slope gradient, the percentage of forest land, and topographic wetness index were more effectively determined WQI variation. Thus, the key controlling factors depend on spatial scales. Both spatial scales and corresponding key controlling factors should be considered in the adjustment of land use composition and planning of landscape configuration to better protect water quality.
了解景观特征对水质的影响可以深入了解减轻水质受损的方法。然而，对于影响水质的关键控制因素尚未达成共识。本文跨多尺度检验了土地利用和地形对水质的综合影响，并确定了控制中国东部横溪水库集水区水质变化的关键因素。水质损害指数（WQI）被定义为一个综合变量，用于衡量整体水质。我们使用偏最小二乘法（PLSR）来探索景观指标的组合，并确定关键控制因素。结果表明，在 50m、100m 和 150m 缓冲区尺度和流域尺度上，最优 PLSR 模型分别解释了 WQI 变化的 77%、63%、60%和 56%。在流域尺度上，斑块密度、水田比例和地形湿度指数是影响水质的关键控制因素。在缓冲区尺度上，坡度梯度、林地比例和地形湿度指数更有效地决定了 WQI 的变化。因此，关键控制因素取决于空间尺度。在调整土地利用组成和景观配置规划时，应同时考虑空间尺度和相应的关键控制因素，以更好地保护水质。
