Spatial Variability Pattern of Hyporheic Exchange in a braided River
The streambed flux is variable in space; the spatial variability results in part from bedforms,but few works on streambed fluxes in channels with strongly abrupt varying bedforms are carried out.Heat as a tracer to delineate the streambed flux pattern has been widely adopted in numerous fields.In this paper,a braided channel with complicated topography was selected as study site,where the temperature was monitored.One-dimensional(1-D)analytical method based on the amplitude attenuation(Ar)and 1-D numerical method were used to interpret the temperature.As a result,streambed fluxes of a total of 50 sites in the braided channel are obtained.From the results we can know the magnitude and direction of streamed flow velocity are spatially variable,even within a 1-m distance.Then,this study summarizes five bedform-driven flux patterns: ① downward flow driven by the head difference between groundwater and stream,② downward flow related to a meter-scale pool,③ a transition from upward to downward flow associated with a centimeter-scale riffle,④ horizontal flow in braided bars and ⑤ upward flow driven by vegetation roots.Overall,multiple physical mechanisms together contributed to the complex streambed flow system,which reflected great challenges for the scaling up of point-in-space seepage flux.
Guangdong Wu Xiao Zhang Jijun Xu
Department of water resources,Changjiang River Scientific Research Institute,Wuhan,Hubei,China;Hubei Changjiang Institute of Survey,Planning,Design and Research,Wuhan,Hubei,China
国际会议
2018 International Symposium on Water System Operations(ISWRSO 2018)(2018年水资源系统及调度国际研讨会)
北京
英文
1-11
2018-10-12（万方平台首次上网日期，不代表论文的发表时间）