跨行政区小流域水污染特征分析

Analysis of water pollution characteristics of small watershed across administrative regions

跨行政区的小流域水污染特征复杂,且因行政主体不同而导致水环境治理困难。以合肥市二十埠河小流域为例,采用现场调查和模型计算相结合的方法,开展流域污染特征分析与研究。结果表明,点源为流域内最重要的污染源,由点源产生的各主要污染物入河负荷贡献率达47.3%~65.4%。各行政区域对河流的污染贡献率存在差异,上游的新站区对二十埠河的污染贡献率最高(COD占比47.88%, TP占比45.67%),下游的肥东县内存在大片农田和散户畜禽养殖,造成NH3-N入河负荷较高(37.96%)。新站区(汛期)和肥东县(非汛期)的NH3-N环境容量为负值,为了实现控制目标,分别需要削减NH3-N入河负荷21.60和81.18 t/a。为改善二十埠河水环境质量,建议将点源污染控制作为流域污染治理工作重点,并做好农业面源污染控制,解决NH3-N环境容量不足的问题。

The characteristics of water pollution in small watersheds across administrative regions are complex,and there are difficulties in water environment governance caused by different administrative entities.Taking Ershibu river small watershed in Hefei as an example,a combination of on-site investigation and model calculation was used to analyze and study the pollution characteristics of the watershed.The results showed that point source was the most important pollution source in the watershed,and the main pollutants generated by point sources contributed 47.3%to 65.4%of the river load.There were differences in the contribution rates of different administrative regions to river pollution.Xinzhan area located upstream had the highest contribution rate to the pollution of Ershibu river(COD accounting for 47.88%,TP accounting for 45.6%),and there were large areas of farmland and scattered livestock and poultry faming in Feidong county located downstream,resulting in a high NH3-N inflow load(37.96%).The NH3-N environmental capacity in Xinzhan area(flood season)and Feidong county(non-flood season)was negative.In order to achieve control goals,it is necessary to reduce NH3-N load into the river by 21.60 and 81.18 t/a respectively.In order to improve the water quality of Ershibu river,it is recommended to take point source pollution control as the focus of watershed pollution management work,simultaneously control agricultural non-point source pollution and solve the problem of insufficient NH3-N environmental capacity in the watershed.