Celerity and Attenuation/Amplification of Supercritical Flow Waves

Supercritical flood waves often occur in open channels with steep slopes. This study investigated the celerity and attenuation/amplification of these waves using the dynamic wave model. Assuming uniform base flow, analytical results showed that flood waves amplify when Froude numbers are greater than 1.5 and attenuate when Froude numbers are less than 1.5. Flood waves with a Froude number equal to 1.5 maintained the same amplitude as they propagated downstream. A flood drainage channel, known as the F1 channel located in Las Vegas, Nevada, was selected as the study site for analyzing celerity and attenuation of flood waves with varying wavelengths. For flood waves in the F1 channel having wavelengths less than 100 m, dimensionless celerity was 1.36–1.38, and the attenuation factor was less than 0.3. Both celerity and attenuation factors increased with wavelength until the wavelength was equal to 1,000 m beyond engineering concerns.