The shear stress which may be selected as output in the HD module is based on the equation
(6.19)
The relation between the friction factor f and the Chezy number C is
(6.20) 
Resulting in
(6.21) 
Or expressed using Manning’s M
(6.22) 
The stress is a vector and may be output both as components in the x- and y-direction and by the absolute size.
