A Comparison of Watershed Surface Coefficients to Present a Unified Time of Concentration for Runoff That Defines Drainage Basin Limits in Green Infrastructure
This paper explores the existing runoff time techniques used in all hydrology evaluations. There are standard methods used to calculate the time it takes stormwater runoff to travel through a specific watershed. This estimated time is used in hydrology to compute a hydrograph’s peak flow. A comparison is established for Manning’s coefficients with a watershed percent impervious surface, rational method coefficients, and NRCS’s soil curve numbers. A typical range of variables are analyzed with NRCS’s velocity time of concentration equations and the results are compared to other time of concentration methods. Time of concentration graphs are created to demonstrate how watershed characteristics effect the watershed's runoff time. These comparisons engage common empirical equations used in time computations for water surface runoff.