Advantages of a mobile LSPIV method for measuring flood discharges and improving stage–discharge curves

摘要: Abstract This paper investigates the potential of fast flood discharge measurements conducted with a mobile LSPIV device. were performed during two hydrological events on Arc River, gravel-bed river in French Alps: greater than 10-year return period May, 2008, and reservoir flushing release June, 2009. The device consists telescopic mast remotely controlled platform equipped video camera. digital camera acquired sequences images surface flow velocities. Ground Reference Points (GRPs) positioned using total station, for further geometrical correction images. During peak, velocities up to 7 m/s large floating objects prevented any kind intrusive measurements. For computation discharge, velocity coefficient was derived from available vertical profiles measured by current meter. obtained value range (0.72–0.79) is consistent previous observations at this site smaller usual default (0.85) or values observed deeper sections (0.90 typically). Practical recommendations are drawn. Estimating stream high conditions entails complex measurement process since many parameters (water level, velocities, bathymetry, coefficient, etc.) affected uncertainties can change experiment. Sensitivity tests, comparisons theoretical considerations reported assess dominant sources error such multiplicative induced confirmed be major source compared estimated errors due water level uncertainty, free-surface deformations, number image pairs, absence presence artificial tracers, cross-section bathymetry profiles. All these 1% 5% whereas variability may 10%–15% according characteristics. analysis 36 both allowed assessment discharges an overall uncertainty less 10%. A simple hydraulic law based geometry three sills Pontamafrey gauging station proposed instead existing curve that fitted data. indicated new more accurate they evenly distributed ±10% interval around it. These results demonstrate interest remote techniques together improving stage–discharge relationships reducing associated discharges.