Abstract
We demonstrate that river discharge can be estimated by combining
satellite-derived video imagery, alongside non-contact velocity
estimation techniques and high-resolution topography. Large Scale
Particle Image Velocimetry (LSPIV) was used to derive surface velocity
maps from 28 s of 5 Hz satellite video acquired at a nominal ground
sampling distance of 1.2 m over the Darling River, Tilpa, Australia
during a 1-in-5-year flood event. We quantified the sensitivity of LSPIV
to varied parametrizations when retrieving surface velocity, and
validated LSPIV velocities against 2D hydrodynamic model simulations.
Discharge was computed using classical velocity-area techniques. Our
results demonstrate accurate inference of discharge (Q ) with
deviations ranging from 0.3 – 15% from gauging station observations.
Precision of Q is influenced by the choice of a surface velocity
depth-averaging coefficient (α ), used in LSPIV. Satellite video
presents a compelling advance for space-based flow velocity and
discharge measurement, especially during flood events, and at ungauged
locations.