Chapter 15 Time of Concentration 630.1500 Introduction This chapter contains information on the watershed characteristics called travel time, lag, and time of concentration. These watershed characteristics influ-ence the shape and peak of the runoff hydrograph. The National Engineering Handbook, Part 630, Hydrology,

Time of concentration (t c) is the time required for an entire watershed to contribute to runoff at the point of interest for hydraulic design; this time is calculated as the time for runoff to flow from the most hydraulically remote point of the drainage area to the point under investigation.

Nov 18, 2013 · Total Time of Concentration. The time of concentration along our sample hydraulic path is simply the sum of the travel times for the overland flow, shallow concentrated flow, and channel flow. T. c = L. o + L. sc + L. c. In our example, the time of concentration is calculated as follows: T. c = 31.5 + 3.57 + 0. T. c = 35.07 So, the time of ...

Travel time ( Tt ) is the time it takes water to travel from one location to another in a watershed. Tt is a component of time of concentration ( Tc ), which is the time for runoff to travel from the hydraulically most distant point of the watershed to a point of interest within the watershed.

Aug 1, 2023 · How to calculate time of concentration? First, determine the flow path length. Measure or calculate the total flow path length or length of the channel. Next, determine the flow path slope. Measure or calculate the slope of the flow path or channel. Finally, calculate the time of concentration.

There are many methods available to estimate the time of concentration including the Kirpich formula, Kerby formula, NRCS Velocity Method, and NRCS Lag Method. The NRCS Velocity and Lag methods are two of the most commonly used methods for determining time of concentration and are described below.

Time of concentration is a concept used in hydrology to measure the response of a watershed to a rain event. It is defined as the time taken by the water to travel (flow) from the most distant or remote point in a watershed to the lowest point or watershed outlet. It is therefore a function of length and slope.

Calculate time of concentration using FAA (rational method), Kirpich, or Kerby equations

Dec 2, 2022 · This article provides the fundamentals required for designing the stormwater management facility, which includes the calculation of Time of Concentration, t c, Time of Overland Flow Time, t o and Time of Drain, t d.

Jan 29, 2025 · In this tutorial, you will be estimating the Tc and R. We will be using an equation that was developed for a Dam Safety Study in Pennsylvania.