Evaluation of river velocity and discharge with a new assimilated method

Abstract

To evaluate accurately river discharge by using the velocities observed at discrete points in a cross section, a new method is presented for data assimilation in which observed velocities are properly incorporated into a river‐flow computation. In the present method, a shallow‐water flow model is adopted, introducing a new additional term to incorporate smoothly the influence of the observed data into the numerical simulation over the whole cross section. The spatially observed velocities can then be interpolated in a cross section by satisfying dynamic principles for fluid motion. The present method is therefore referred to be here as a dynamic interpolation method. To confirm the fundamental performance of the dynamic interpolation method, the present method has been applied to the spatial interpolation of velocities in a cross section with the simulation data for a river‐flow computation done by the authors. The interpolated results indicate that the present method can have high accuracy for the evaluation of river velocity and discharge.

Keywords:

• Data assimilation
• river flow
• discharge
• dynamic interpolation method
• ADCP