The effect of hydraulic resistance on the downstream evolution of the water surface profile h in a sloping channel covered by a uniform dense rod canopy following the instantaneous collapse of a dam was examined using flume experiments. Near the head of the advancing wave front, where h meets the rods, the conventional picture of a turbulent boundary layer was contrasted to a distributed drag-force representation. The details of the boundary layer around the rod and any interferences between rods was lumped into a drag coefficient C_d. The study demonstrated the following: In the absence of a canopy, the Ritter solution agreed well with the measurements.