Mohammad Vaghefi

Protecting the downstream side of culverts against the scouring phenomenon is deemed a vital point to consider when designing culverts, which are structures utilized as water passages. This study represented an attempt to investigate the effect of artificial roughness on the scouring happening at the downstream side of culverts. To this end, 37 tests with three variable parameters of height, length lateral to the flow, and the distance between rows of artificial roughness were conducted. The results revealed the greater role artificial roughness height played in mitigating the scouring than the rest of the parameters did compared to the control test. Furthermore, the greatest reduction of the scour depth was observed when height, length perpendicular to the flow, and the distance between rows of artificial roughness were respectively equal to 0.13, 0.26 and 0.8 times the culvert mouth height. More than 17% decrease in the maximum scour depth was found in tests conducted under these conditions compared to the control test. In addition, the greatest rise in sedimentation volume was observed when the dimensions were respectively 0.33, 0.33 and 0.66 times the culvert mouth height. This test indicated 9% increase in the sedimentation volume compared to the control test.