In mountainous streams, submergence over roughnesses is major factor which affects the U/u* (here, U is average velocity of flow and u* = shear velocity over the bed), Graf while developing his model assume von Karman's constant to be constant but due to low submergence and variability of size of roughness which according to Emadzadeh et al. (2010) makes it non-universal and non-constant but rather a coefficient. So how one can estimate velocity and turbulence parameters in steep mountainous stream which are largely dependent of 3D flow field?