荆江三口2016~2020年主要污染物入洞庭湖通量分析

Analysis on the Flux of Major Pollutants into Dongting Lake from the Three Outlets on Jingjiang Reach from 2016 to 2020

摘要: 荆江三口是连接荆江河段与洞庭湖区的纽带，作为入湖河流，其污染物浓度及通量的时空变化特征备受关注。本文采用水质、水量、污染物通量等多要素综合分析方法，研究了2016~2020年荆江三口水系8个监测断面水质和污染物通量的时空分布、变化趋势及原因。结果表明：① 2016~2020年三口河流水体水质总体状态良好，I~III类水年均比例为83.3%~94.4%，汛期水体质量优于非汛期。② 2016年至2020年荆江三口水系总入湖径流量松滋河 > 藕池河 > 虎渡河，分别占总入湖径流量的52.86%、37.27%和9.87%。③ 非汛期COD_Mn和NH₃-N平均浓度大于汛期，TP平均浓度汛期大于非汛期。④ 三口水系主要污染物总入湖通量COD_Mn、TP、NH₃-N分别为63.11 × 10⁴、2.54 × 10⁴、6.25 × 10⁴ t，月平均入湖通量分别为1.13 × 10⁴、4.54 × 10²、1.12 × 10³ t，三口水系污染物入湖通量松滋河 > 藕池河 > 虎渡河，松滋河入湖主要污染物占比58.90%~66.15%，虎渡河占比最小为11.24%~14.16%。

Abstract: Three Outlets on Jingjiang reach are the link connecting Jingjiang River and Dongting Lake area. As the river flowing into Dongting Lake, the temporal and spatial variation characteristics of pollutant concentration and flux have attracted much attention. In this paper, water quality, water quantity, pollutant flux and other multi factor comprehensive analysis methods are used to study the temporal and spatial distribution, change trend and causes of water quality and pollutant flux of 8 monitoring sections of the Three Outlets on Jingjiang reach water system from 2016 to 2020. The results show that: ① From 2016 to 2020, the water quality of the Three Outlets is generally in good condition. The average annual proportion of Class I to III water is 83.3%~94.4%, and the water quality in flood season is better than that in non-flood season. ② From 2016 to 2020, the total inflow of the Three Outlets on Jingjiang reach into the Dongting Lake is Songzi River > Ouchi River > Hudu River, accounting for 52.86%, 37.27% and 9.87% of the total inflow respectively. ③ The average concentration of COD_Mn and NH₃-N in non-flood season is higher than that in flood season, and the average concentration of TP in flood season is higher than that in non-flood season. ④ The total fluxes of main pollutants into the lake of the Three Outlets systems COD_Mn, TP and NH₃-N are 63.11*10⁴, 2.54*10⁴, 6.25*10⁴ t, the monthly average flux into the lake is 1.13*10⁴, 4.54*10², 1.12*10³ t, the flux of pollutants from the Three Outlets systems into the lake is Songzi River > Ouchi River > Hudu River, the main pollutants from Songzi River into the lake account for 58.90%~66.15%, and the minimum proportion of pollutants from Hudu River is 11.24%~14.16%.