A New method to measure slope in large rivers using tracers.

Abstract

The use of tracers on small and medium rivers is a practice very common for calculate hydraulics characteristics and its hydrodynamic with excellent results, however in large rivers has not been common the use tracers for calculate hydraulics variables. For that reason some researchers used the concept about transport coefficient as time function to calculate the slope of large rivers by means of Elder ́s equation presented in 1959. The aim of this paper is to show why this equation is quite correct, despite the incongruence with these “reference values” which had an inaccurate foundation. Put in this new perspective, the Elder ́s equation may give useful values for slope, especially in those cases where is very difficult to measure by means of other methods. It is presented here a detailed experimental application of methodology to a large river in Colombia with great results.