Methodology for Identifying the Best Equations to Estimate the Time of Concentration of Tropical Watersheds in Puerto Rico

Abstract

The time of concentration (tc) is the time required for runoff to travel from the hydraulically most distant point to the outlet of a watershed. The lag time is the most sensitive parameter and is defined as the sixty percent of the tc. This research was focused in the evaluation of the use of time of concentration parameter in Puerto Rico and also if the parameter are used correctly for the conditions for which they were created in order to define a methodology for the best use of each available equation. The NRCS velocity method was used as the reference method for computing time of concentration value and compare the accuracy of the estimates from other time concentration methods. This research illustrated the high variability associated with the time of concentration values depending on the method employed. According to this research, the SCS Lag equation have the best performance for the selected seven watersheds analyzed. Key Terms - Peak Discharge, Sensitive Parameter, Time of Concentration, Tropical Watershed.