Definition of the bankfull hydraulics of rivers would provide a baseline condition for quantification of large-scale regional changes in river morphology through remote tracking of variables including width,stage,and slope,and serve as a reference for remote tracking of hydraulic dynamics.So,bankfull characteristics are important parameter to indify the fluvial estate of river reach.In order to reveal the variation ofbankfull discharge in the lower Wei River,the bankfull discharge is analyzed by steady one-dimensional model.