How sediment dredging alters phosphorus dynamics in a lowland rural river?  

作　　者：Qimou Zhang Jiacong Huang Yulai Ji Jing Zhang Shuai Zhang Junfeng Gao 

机构地区：[1]Key Laboratory of Watershed Geographic Sciences,Nanjing Institute of Geography and Limnology,Chinese Academy of Sciences,Nanjing 210008,China [2]University of Chinese Academy of Sciences,Beijing 10094,China

出　　处：《Journal of Environmental Sciences》2025年第1期189-199,共11页环境科学学报(英文版)

基　　金：supported by the National Key Research and Development Program of China(No.2021YFD1700600);the National Natural Science Foundation of China(Nos.42222104 and 41971138);the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDA23020201);and the Science and Technology Planning Project of NIGLAS(No.NIGLAS2022GS10).

摘　　要：China’s lowland rural rivers are facing severe eutrophication problems due to excessive phosphorus(P)from anthropogenic activities.However,quantifying P dynamics in a lowland rural river is challenging due to its complex interaction with surrounding areas.A P dynamic model(River-P)was specifically designed for lowland rural rivers to address this challenge.This modelwas coupled with the Environmental Fluid Dynamics Code(EFDC)and the Phosphorus Dynamic Model for lowland Polder systems(PDP)to characterize P dynamics under the impact of dredging in a lowland rural river.Based on a two-year(2020-2021)dataset from a representative lowland rural river in the Lake Taihu Basin,China,the coupled model was calibrated and achieved a model performance(R^(2)>0.59,RMSE<0.04 mg/L)for total P(TP)concentrations.Our research in the study river revealed that(1)the time scale for the effectiveness of sediment dredging for P control was~300 days,with an increase in P retention capacity by 74.8 kg/year and a decrease in TP concentrations of 23%after dredging.(2)Dredging significantly reduced P release from sediment by 98%,while increased P resuspension and settling capacities by 16%and 46%,respectively.(3)The sediment-water interface(SWI)plays a critical role in P transfer within the river,as resuspension accounts for 16%of TP imports,and settling accounts for 47%of TP exports.Given the large P retention capacity of lowland rural rivers,drainage ditches and ponds with macrophytes are promising approaches to enhance P retention capacity.Our study provides valuable insights for local environmental departments,allowing a comprehensive understanding of P dynamics in lowland rural rivers.This enable the evaluation of the efficacy of sediment dredging in P control and the implementation of corresponding P control measures.

关 键 词：Lowland rural river PHOSPHORUS Sediment dredging Model ensemble Retention capacity 

分 类 号：TV1[水利工程]