Travel Time / Time of Concentration Calculator

Calculate the travel time (or time of concentration) for channelized or shallow concentrated flow.
\( V = \frac{1.49}{n}\, R^{\frac{2}{3}} \sqrt{S} \) and \( T = \frac{L}{V} \)

* Enter the flow length \(L\) (ft), channel slope \(S\) (ft/ft), Manning’s roughness \(n\), and hydraulic radius \(R\) (ft).

Step 1: Enter Parameters

Flow Length, \(L\) (ft):

Example: 1000 ft

Channel Slope, \(S\) (ft/ft):

Example: 0.001 ft/ft

Manning’s Roughness, \(n\):

Example: 0.015

Hydraulic Radius, \(R\) (ft):

Example: 2 ft

This calculator uses Manning’s equation to estimate the flow velocity and then calculates the travel time (or time of concentration) as the ratio of the flow length to velocity.

Step 1: Enter Parameters

Calculated Travel Time / Time of Concentration