A basic topic in river studies, whether in hydrodynamics or water quality, is the accurate estimation of both geomorphological and geometric characteristics in cross sections in streams or channels. Many measurements or methodologies that are within the state of the art, are not direct or easy by several aspects. For this reason, this article analyses the application of a state function, Ф (t), which, acting as a thermodynamic potential, allows the magnitudes of the cross sections, depth of the water sheet, slope and longitudinal dispersion coefficient to be obtained directly, using NaCl as a tracer. In order to apply and validate this new method properly, an experiment conducted in 1966 by H.B. Fischer in the W.M. Keck Laboratory of Caltech in USA was studied on two points of the canal. It found average differences of 0.016 m2 (with reference) in the area of the canal, 0.015 m of the height of the water sheet and an average difference of -0.00015 in the slope of the canal
• Glories, hidden rainbows and nearside-farside interference effects in the angular scattering of the state-to-state H + HD → H2 + D reaction
