The bed Scour near the outer bank in the curved reach of natural rivers is generally caused by the secondary flow and it tends to become exaggerated by the formation and movement of alternate bars, Experimental and theoretical works are conducted in order to investigate that vane works provide a useful means to reduce the scour depth even in such a curved channel. The lateral bed profile obtained by the theory is found to be in a fairly good coincidence with observed one and the PWRI vane functions well so as to reduce the scour depth produced by the secondary current and alternate bar formation