How do you calculate overland flow?
Quote: The average length of overland flow was determined by dividing the watershed area by twice the total length of all waterways.
What is time of concentration in a watershed?
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 needed for water to flow from the most remote point in a watershed to the watershed outlet. It is a function of the topography, geology, and land use within the watershed.
What is time of concentration in drainage?
Time of concentration (Tc) is the time required for runoff to travel from the hydraulically most distant point in the watershed to the outlet.
What is the overland flow length?
From the sketches of Figure 7-10 it should be clear that the overland flow length is the distance from the boundary of the idealized rectangle to the drainage conduit (pipe or channel). It is along the overland flow length that the surface gradient should be estimated.
How do you calculate TC from AVC?
The way to find the AVC is : TC at 0 output is 5 which means fixed cost (FC) is 5. Hence, if we subtract 5 from the TCs for all the subsequent output levels we will get the VC at each output. Now, AVC = VC /Q. Which is easy to find.
What is the best book on overland flow concentration formulas?
WONG, T. S. W. “Assessment of ti me of concentration formulas for overland flow. Journal of Irrigation and Drainage Engineering, v. 131, n. 4, 2005. 54. WONG, T. S. W. Evolution of Ki nematic Wave Time of Concentration Formulas for Overland Flow. Journal of Hydrologic Engineering, v. 14, n. 7, 2009. 55. WOOLHISER, D.A. & LIGGETT, J.A. Unsteady,
How do you calculate the time of concentration of a stream?
Time of Concentration 1 Consider stream sinuosity in calculating stream length 2 Consider the pools in the stream as they slows down the flow and thereby reduces the flow velocity. 3 Don’t underestimate the Manning’s roughness coefficient ‘n’ within the channel.
What is the total time of concentration for a watershed?
Adding the overland flow and channel flow components gives total time of concentration for a watershed of about 57 minutes. Finally, as a quick check, the analyst can evaluate the t c by using an ad hoc method representing t c, in hours, as the square root of drainage area, in square miles.
Which time of concentration equation is better for hydrological design?
The main conclusion emphasizes that the empirical equation of the time of concentration that shows a better fit is the median value of all empirical equations. The equations of Kirpich, Passini, California, SCS and Ventura-Heras are more conservative for hydrological design because show lower time values and therefore faster hydrological responses.