【目的】提出一种能够定量反映面源污染影响的水源地保护区划定方法，解决当前划定方法中难以量化面源污染影响的问题。【方法】基于水文模拟方法，综合考虑地理属性与生态属性，提出了一种新的水源地划分方法。采用SWAT模型结合输出系数法和改进的反距离权重插值法，计算水源地陆域污染物入河量，通过陆域保护区划分方法，并结合地形剖面，对陆域保护区范围进行进一步的校核与修正。【结果】以渠江流域为研究对象，运用本文方法重新划定其水源地保护区。与原区划相比，各等级保护区的污染物负荷总量均减少了5%，原有超标状况均改善为达标状态。【结论】通过合理量化面源污染对保护区范围的影响，能够显著优化水源地保护区划定结果，提升保护区划分的科学性与可操作性。本研究提出的方法在渠江流域的应用具有较高适用性，可为我国水源地污染防治与保护区划分提供参考依据。
【Background】River-type water sources are widely distributed in China and serve as the primary source of drinking water. Over the past decades, the proportion of non-compliant water sources has decreased due to effective control of point-source pollution. However, this trend has slowed in recent years, with non-point source pollution increasingly affecting water quality. Current protection methods mainly rely on empirical analogies, making it difficult to quantitatively delineate protection zones for non-point source pollution.【Objective】This study proposes a novel method for delineating water source protection zones that quantitatively accounts for the impacts of non-point source pollution, addressing the limitations of existing approaches in accurately reflecting such influences.【Method】Based on hydrological modeling, this method integrates geographic and ecological attributes to establish a refined framework for delineation. The SWAT model, coupled with the export coefficient method and an improved inverse distance weighting interpolation method, was employed to calculate terrestrial pollutant loads entering water bodies. Natural background conditions were incorporated into the assessment of terrestrial pollutant input. A terrestrial protection zone delineation formula was applied, and further adjustments were made by cross-verifying with topographic profiles.【Result】① The re-delineation of the water source protection zones using the proposed method resulted in a 5% reduction in pollutant load across different protection levels compared to the original zoning.② All protection zones, which previously exceeded standards, now comply with water quality standards, showing improved accuracy and reasonability.【Conclusion】By effectively quantifying the influence of non-point source pollution on protection zone boundaries, the proposed method significantly enhances the precision and applicability of water source protection zoning. The findings highlight the high suitability of this approach for the Qujiang River Basin and its potential to inform pollution prevention and protection zone delineation across China.
