Local scour around bridge piers is one of the most destructing factors in bridge failure. Studies have shown that 60 percent of the bridge failure can be related to the local scour around bridge piers or other hydraulic phenomena. Up to now a good deal of research has been carried out on the effect of different factors on the development of the scour depth using physical models. In spite of considerable efforts made to understand the effect of side wall on the scour depth development, a comprehensive study of this phenomenon has yet to be established. The main aim of the present research was to improve knowledge 'of the effect of the side wall on the scour depth. Experimental results showed that, in order to achieve maximum scour depth, the D/W scale should be attained around 0.11. It was also found that scale parameter D/W greater than 0.11 created a reduction of up to 35 percent in the depth of the scour hole.