三峡水库干支流交互作用下典型支流回水区氮磷分布特征  

Distribution Characteristics of Nitrogen and Phosphorus in the Backwater of Typical Tributaries Under the Interaction of Main Stream and Tributaries in the Three Gorges Reservoir

作　　者：王超[1,2] 贺天明 吴事典 辛小康 白凤朋[1,2] 贾海燕 赵肥西 吴菲[3,5] 尹炜 WANG Chao;HE Tian-ming;WU Shi-dian;XIN Xiao-kang;BAI Feng-peng;JIA Hai-yan;ZHAO Fei-xi;WU Fei;YIN Wei(Changjiang Water Resources Protection Institute,Wuhan 430051,China;Key Laboratory of Ecological Regulation of Non-point Source Pollution in Lake and Reservoir Water Sources,Changjiang Water Resources Commission,Wuhan 430051,China;Yangtze Ecology and Environment Co.,Ltd.,Wuhan 430000,China;College of Environment,Hohai University,Nanjing 210098,China;College of Civil Engineering and Environment,Hubei University of Technology,Wuhan 430068,China)

机构地区：[1]长江水资源保护科学研究所,湖北武汉430051 [2]长江水利委员会湖库水源地面源污染生态调控重点实验室,湖北武汉430051 [3]长江生态环保集团有限公司,湖北武汉430000 [4]河海大学环境学院,江苏南京210098 [5]湖北工业大学土木建筑与环境学院,湖北武汉430068

出　　处：《长江流域资源与环境》2024年第2期387-397,共11页Resources and Environment in the Yangtze Basin

基　　金：国家自然科学基金项目(U2040210);国家重点研发计划项目(2021YFC3200304)。

摘　　要：三峡水库成库后支流形成回水区,认识干支流交互作用下支流回水区氮磷分布特征,对于理解支流水华形成机制具有重要意义。以三峡水库典型支流香溪河为对象,通过汛期和蓄水期回水区分层采样,利用水温和电导率表征水体分层,并分析氮磷浓度、形态组成、氮磷比例的分布特征。结果显示,汛期水体垂向分层明显,TP(0.04~0.33 mg/L)、TN(0.57~2.36 mg/L)和NH3-N(0.03~0.20 mg/L)上游和河口高于中间,DTP(0.01~0.23 mg/L)、DTN(0.2~2.0 mg/L)和NO3-N(0.96~1.77 mg/L)上游高于下游;磷以颗粒态为主(DTP/TP 0.13~0.19),氮以溶解态为主(DTN/TN 0.88~0.91);氮磷比例(TN/TP 1.3~139)中间最高。蓄水期水体垂向分层减弱,氮磷浓度差异减小(TP 0.05~0.17 mg/L,TN 1.48~1.91 mg/L);氮磷均以溶解态为主(DTN/TN 0.57~0.77,DTP/TP 0.63~0.68);氮磷比例(TN/TP 23~86)河口到上游逐步降低。汛期长江干流对支流倒灌和上游输入导致氮磷梯度差异较蓄水期更为显著;蓄水期长江干流泥沙颗粒补给减少造成溶解态氮磷占比高于汛期;氮磷比例的变化可能是干流顶托、泥沙颗粒沉降和上游输入共同作用的结果。研究结果表明,干支流交互作用对支流回水区氮磷分布起到重要的驱动作用。After the impounding of the Three Gorges Reservoir,flows from the tributaries formed the backwater area.It is important to understand the distribution characteristics of nitrogen and phosphorus in the backwater under the interaction of main stream and tributaries for a better understanding of the formation mechanism of tributary algae bloom.Xiangxi River,a typical tributary of the Three Gorges Reservoir,was taken as the study object.The distribution characteristics of nitrogen and phosphorus concentration,composition and N/P ratio were analyzed by stratified sampling in the backwater area during flood period and storage period.The results showed that during flood seasons,the water body showed vertical stratification,TP(0.04-0.33 mg/L),TN(0.57-2.36 mg/L)and NH3-N(0.03-0.20 mg/L)were higher in the upstream and estuarine than that in the middle reach.DTP(0.01-0.23 mg/L),DTN(0.2-2.0 mg/L)and NO3-N(0.96-1.77 mg/L)decreased gradually from upstream to downstream.The phosphorus was mainly in the form of particles(DTP/TP 0.13-0.19),and nitrogen was mainly in dissolved state(DTN/TN 0.88-0.91).The N/P ratio(TN/TP 1.3-139)was the highest in the middle.During storage periods,the vertical stratification was weakened,and the difference of nitrogen and phosphorus concentration was decreased(TP 0.05-0.17 mg/L,TN 1.48-1.91 mg/L).Nitrogen and phosphorus were mainly in the dissolved form(DTN/TN 0.57-0.77,DTP/TP 0.63-0.68).N/P ratio(TN/TP 23-86)gradually decreased from estuary to upstream.The gradient difference of N and P was more significant in flood seasons than in storage seasons.The decrease of sediment particle recharge from the Yangtze River main stream during impoundment periods resulted in a higher proportion of dissolved nitrogen and phosphorus than that in flood seasons.The change of N/P ratio may be resulted from the combined effects of the main stream overburden,the sedimentation of sediment particles and the upstream inputs.The results show that the interaction between main stream and tributary plays an important role i

关 键 词：三峡 香溪河 干支流 交互作用 营养盐 分布特征 

分 类 号：X824[环境科学与工程—环境工程]