Stream Cross-Section for Q Measure V (current-meter) at 0.2 and 0.8 of depth Average V and multiply by (width * depth) Sum up across stream to get total Q = S (Vi Di Wi)

Rating curve hysteresis loop in Zenne river (Lot), 15-16 July 2012 event: blue triangles – rising stage, green squares – falling stage

Flume tests carefully conducted by Nomicos (1957) at CalTech: constant-depth, unique sediment size d=0.152mm difficult to reconcile with the standard formulation for the ‘alluvial resistance coefficient’:

.

Bed-material discharge Buoyancy-affected turbulence Bed morphology adaptation Alluvial resistance

Hyperbolic tangent of x = tanh x = (ex - e-x)/(ex + e-x)

If lBF is the wavelength from crest to crest, the celerity of the associated gravity wave is given by Airy’s law:

Facteur m Ok théorie m = 1,1 m = 1,2

Discontinuity rating curve original discontinuity rating curve Modified discontinuity rating curve