Author(s): Brilly Mitja; Rusjan Simon; Padeznik Matej; Vidmar Andrej
Linked Author(s): Mitja Brilly
Keywords: Discharge estimation; Ultrasonic Doppler instruments; Flow velocity; Rising limb; Falling limb
Abstract: Accurate discharge estimation is crucial for an efficient river basin management and especially for flood forecasting and warnings related to possible extreme flood events. By using ultrasonic Doppler instruments we recorded the actual relation between the water stage and the flow velocity at the occurrence of flood waves. Unsteadiness in the water stage – water velocity relation causes the trajectory of the flood event to appear as a loop on the stage-velocity diagram. Results of the 6-year measurements at water stations on the Reka river experimental watershed and its tributaries (Padez and Suhorka) show non-negligible differences in water velocities on the rising and falling limbs of the flood waves at the same water stage. Together with seasonal differences in water velocity, which were also observed, the “classic” use of rating curves can therefore lead to great errors in discharge estimation.
Year: 2007