基于入库负荷精细解析的面源污染排放特征识别

Identification of non-point source pollution emission characteristic based on fine detailed analysis of inflow pollution load

摘要

【目的】为厘清流域面源污染源结构、精细化解析面源污染负荷时空特征，【方法】以SWAT(Soil and Water Assessment Tool)流域面源污染模型为基础，选取代表性水文系列，结合入库污染负荷计算模型，构建了污染负荷量及入库强度的面源污染关键源区识别技术流程，并在数据条件较为完备的沙河水库流域进行验证。【结果】结果表明：沙河水库流域总氮(Total Nitrogen, TN)入库负荷总量为198.34 t/a,面源污染占比为86.53%,流域内茶园TN负荷量贡献率最大，占比为23.84%;TN负荷量在丰水年和特丰水年比枯水年上升58.06%和289.09%,在年内丰水期TN月均负荷量比平水期和枯水期分别高出75.24%和372.51%;河道削减TN负荷量为33.58 t/a,削减比例为14.48%;子流域TN入库产污强度变化范围为0.36~4.73 t/km²。面源污染排放入库低值区主要位于流域南部，高值区主要位于近库区域，沙河西和沙河东控制分区单位面积TN入库强度显著高于流域南部。【结论】针对高产污地类、高产污区域及高产污时段应提高面源污染防控力度；建立的技术流程可有效识别和科学解析流域面源污染关键源区，为流域水环境开展面源污染防治和生态适应性开发提供一定技术支持，使相关工作开展更加有的放矢。

Abstract

[Objective] This study aims to clarify the structure of non-point source pollution in the watershed and conduct a detailed analysis of the spatial and temporal characteristics of non-point source pollution loads. [Methods] The SWAT(Soil and Water Assessment Tool) watershed non-point source pollution model was used as a basis., Representative hydrological series wereas selected, and combined with an inflow pollution load calculation model., A technical process was developed to identify key non-point source pollution areas based on pollution load and inflowintensity. This process was verified in the Shahe Reservoir watershed, where data conditions were relatively complete. [Results] The results showed that the total inflow load of total nitrogen(TN) in the Shahe Reservoir watershed was found to be 198.34 t/a, with non-point source pollution accounting for 86.53% of this load. The largest contribution to the TN load came from tea gardens in the watershed, contributing 23.84%. The TN load during wet years and extremely wet years increased by 58.06% and 289.09%, respectively, compared to dry years., During the wet season, the average monthly TN load was 75.24% and 372.51% higher than in the normal and dry seasons, respectively. The river reduced the TN load by 33.58 t/a, with a reduction ratio of 14.48%. The variation in TN inflow pollution intensity across sub-watersheds ranged from 0.36 t/km² to 4.73 t/km². The low-value zones for non-point source pollution emissions were primarily located in the southern part of the watershed, while the high-value zones were concentrated near the reservoir. The incflow TN intensity per unit area in the Shahe West and Shahe East control sub-zones was significantly higher than in the southern part of the watershed. [Conclusion] Pollution control efforts should be strengthened in areas with high pollution yieldss, high pollution regions, and during high pollution periods. The established technical process can effectively identify and scientifically analyze key non-point source pollution areas in the watershed, providing technical support for non-point source pollution prevention and ecological adaptive development in watershed water environments. This will ensure more targeted and effective pollution control measures.

关键词

面源污染 / SWAT模型 / 总氮 / 特征识别 / 沙河水库

Key words

non-point source pollution / SWAT model / total nitrogen / characteristic identification / Shahe Reservoir

基金资助

国家重点研发计划(2023YFC3209001)

广西重点研发计划(AB22035075)

广西重点研发计划(AB22080093)