The aim of the study is to provide an insight to the factors controlling the flow retardation, the role of form-induced velocity and skin shear stresses within the submerged boulder array in a gravel-bed stream. An acoustic Doppler velocimeter was used for flow measurements in a laboratory flume and the results are compared with those acquired from ANSYS CFX based simulation keeping the hydraulic conditions similar. Boulders are arranged over an immobile gravel-bed with a spacing of ten times the boulder diameter. The time-averaged velocity at the near-wake flow zones of boulder experiences reversible flow owing to form-induced velocity. In near-wake flow zone of boulder, it is estimated that the form roughness is twice as high as the skin roughness. In away flow zone, the magnitude of form roughness reduces indicating a borderline effect in comparison to skin roughness. The influence of skin shear stresses on the streamwise velocity profiles exist upto five times of boulder diameter towards downstream. Also, the minimum skin shear stresses is obtained just downstream at the boulder trough with a non-dimensional value of -0.57 implicating flow reversal whereas; at the crest of the boulder shear stress is found maximum owing to boulder-induced shear stresses.