Understandably, some visitors to this server have not yet done the necessary calculations. This segment presents a simplified version of the calculations.
In the form provided below, input the design flow, channel geometry, and a reasonable guess at Manning's "n". Use the tables below for help in finding a Manning's "n" and a Kb value. These calculations are for unvegetated channels only. The Manning's "n" equations for vegetated conditions are quite complex and hence are ignored in this server.
Note that the unvegetated assumption is not a defficiency; rather,
it provides a conservative estimate of the developed stresses and velocities. Vegetated channels can withstand higher velocities and shear stresses than their unvegetated counterparts. The idea here is that if the flexible lining can withstand the unvegetated condition, then the lining will survive the vegetated condition as well.
If you are unsure of what values to select, visit the HELP page.
