The Colebrook-White Formula is used for Velocity calculations within the software
where:
V = Velocity, (m/s)
g = Gravitational acceleration
S = Hydraulic gradient (m/m)
v = Kinematic viscosity of fluid (m²/s)
ks = Effective roughness
D = 4 * Hydraulic Radius (m)
Typical ks values for storm drainage are 0.6 mm and 1.5 mm for sanitary sewage pipes.
Note: InfoDrainage uses a fixed viscosity value of 1 centistoke = 1E-06 m²/s