摘要
非点源污染风险时空分布特征解析和等级分区是有效控制非点源污染的关键.为了弥补PNPI(potential non-point pollution index,潜在非点源污染指数)模型中专家评价法主观赋权的不足,引入均方差决策法,并采用改进后的PNPI模型分析1980—2017年北京市北沙河上游流域潜在非点源污染风险时空变化特征,划分潜在非点源污染风险等级.结果表明:①均方差决策法根据土地利用指标、径流指标和距离指标集的数值离散程度确定各指标权重,其结果可体现各指标权重随土地利用类型动态变化的特点.②1980—2017年土地利用指标、径流指标和距离指标的平均权重分别为0.49、0.18、0.33,说明土地利用类型对非点源污染风险相对影响较大.③受土地利用类型空间分布格局影响,北沙河上游流域潜在非点源污染风险呈西北部山区低、东南部平原区高的分布特征.④随着城镇化的推进,潜在非点源污染极高风险区主要土地利用类型由旱地和园地逐渐演变为城镇用地、农村居民地和建设用地.研究显示,非点源污染风险高低与土地利用类型密切相关,可通过土地利用类型的合理布局,降低流域非点源污染风险.
Detection of non-point source pollution risk spatial distribution and plotting non-point source pollution risk regions are critical for non-point source pollution control.In this study,the mean-square deviation decision method is employed to replace the traditional expert evaluation method usually used in the potential non-point source pollution index(PNPI)model,and the revised PNPI model is used to analyze the spatio-temporal variation of potential non-point source pollution risk in the upper reaches of the Beisha River from 1980 to 2017.The results show that:(1)The mean-square deviation decision method can determine the weights of land use,runoff and distance indices according to the numerical dispersion degrees of each of the index set,its result can reflect the changes of index weights with land use cover change(LUCC).(2)The average weights of land use,runoff and distance indices from 1980 to 2017 determined by the mean-square deviation decision method are 0.49,0.18 and 0.33,respectively,which indicates that land use types have higher impacts on the potential non-point source pollution risk.(3)Affected by the spatial distribution pattern of land use types,extremely low and low non-point source pollution risk regions are mainly distributed in the forest-covered northwestern areas,while high and extremely high risk regions are mainly located in the southeastern plain areas in the upper reaches of the Beisha River.(4)As the result of urbanization,the main types of land use for extremely high-risk areas of potential non-point source pollution risk have gradually evolved from dry land and garden land before 2000 to urban land,rural residential land and construction land in 2010 and 2017.The research shows that the risk of non-point source pollution is closely related to land use pattern,and each land use mode should be rationally arranged to reduce non-point source pollution risk.
作者
时迪迪
张守红
王红
SHI Didi;ZHANG Shouhong;WANG Hong(School of Soil and Water Conservation,Beijing Forestry University,Beijing 100083,China;Beijing Changping District Water Authority,Beijing 102200,China)
出处
《环境科学研究》
EI
CAS
CSCD
北大核心
2020年第4期921-931,共11页
Research of Environmental Sciences
基金
国家水体污染控制与治理重大专项(No.2017ZX07102-001)。
关键词
非点源污染
风险分区
潜在非点源污染指数(PNPI)模型
均方差决策法
北沙河
non-point source pollution
risk zoning
potential non-point source pollution index(PNPI)model
mean-square deviation decision method
Beisha River
