Numerical approximation of the hydrological time of concentration

The time of concentration, that is the it takes for a single "drop water" to move superficially from most distant point watershed exit point, fundamental parameter hydrological analysis. Many studies have been conducted propose empirical formulas calculate concentration. One best known Temez formula based on series data collected in accounts Spain with areas less than 3,000 km2. This expression uses main channel length as many works, small slopes approximated by distance between geographic coordinates starting and ending points, leading larger catchments approaches high error. In this work, using proper discretization curve, polynomial interpolation methods, we improve calculation therefore, provide more reliable method calculating concentration expression. We illustrate proposed scheme different numerical examples comparing results those provided other methods.