State Key Laboratory of Subtropical Building Science, South China University of Technology, Guangzhou, 510640, China.
Guangdong Engineering Technology Research Center of Safety and Greenization for Water Conservancy Project, Guangzhou, 510641, China.
Environ Sci Pollut Res Int. 2021 Apr;28(13):16602-16615. doi: 10.1007/s11356-020-12196-8. Epub 2021 Jan 3.
Landscape patterns have a substantial effect on non-point source (NPS) pollution in watersheds. Facilitating sustainable development of mountain-rural areas is a major priority for China. Knowledge of the impacts of various landscapes on water quality in these areas is critical to meeting environmental goals. This study applied the Soil and Water Assessment Tool (SWAT) to create a hydrologic and water quality model of the study watershed; then, the relationship between water quality and landscape patterns was investigated using multiple linear regression and redundancy analysis. The results show that the western sub-basins had higher nitrogen pollution loads, and the total nitrogen concentration reached a maximum value of 3.91 mg/L; the eastern sub-basins had a higher pollution load of phosphorous featured by maximum total phosphorous concentration of 2.15 mg/L. The water quality of the entire watershed in all scenarios tended to deteriorate over time. Landscape metrics accounted for 81.7% of the total variation in pollutant indicators. The percentage of forest landscape was negatively correlated with NPS pollution, while other types of landscape showed a positive correlation. The patch density, landscape shape index, and largest patch index of urban and agricultural lands were negatively correlated with pollutant concentrations. Upland landscapes contributed more pollutants than paddy fields. Some measures, e.g., returning grassland and farmland to forest in steep regions and replacing upland crops with paddy fields, were recommended for mitigating NPS pollution in the study watershed.
景观格局对流域非点源（NPS）污染有很大影响。促进山区农村的可持续发展是中国的主要优先事项。了解这些地区各种景观对水质的影响对于实现环境目标至关重要。本研究应用土壤和水评估工具（SWAT）创建了研究流域的水文和水质模型；然后，使用多元线性回归和冗余分析研究了水质与景观格局之间的关系。结果表明，西部子流域的氮污染负荷较高，总氮浓度达到 3.91mg/L 的最大值；东部子流域的磷污染负荷较高，总磷浓度达到 2.15mg/L 的最大值。在所有情景下，整个流域的水质随着时间的推移趋于恶化。景观指标占污染物指标总变异的 81.7%。森林景观的比例与 NPS 污染呈负相关，而其他类型的景观则呈正相关。城市和农业用地的斑块密度、景观形状指数和最大斑块指数与污染物浓度呈负相关。旱地景观比水田景观产生更多的污染物。建议采取一些措施，如在陡坡地区将草地和耕地退还给森林，以及用水田代替旱地作物，以减轻研究流域的 NPS 污染。
