Laboratory investigation of methods to reduce the scouring of the downstream stilling basin (Case study: masonary check dam of Vatana)

It is common to use correction dams to stabilize riverbeds and build stilling basin to deplete energy downstream of these structures. However, we still see the erosion of riverbeds downstream of these structures. One of the effective ways to reduce scouring phenomenon is to create a submerged hydraulic jump inside the stilling basin.Therefore, in the current research, the changes in scour depth in the downstream masonary check dam 0f vatana structure located in Golestan province were investigated and evaluated by building a physical model with a scale of 1:10. so that by reducing its downstream erosion, it can increase the performance and lifespan of the structure in order to protect the river bed. Two methods were used, including raising the end of the channel and using Submerged Vanes along with layer armor immediately after the stilling basin.In the ipnvestigation of the method of using Submerged Vanes with a zigzag arrangement, the lowest percentage of scouring depth reduction was 43.3% of the value observed in the control test. And the method of raising the end of the channel equal to twice the taillwater depth of the abutment with an armor layer 1.5 times the length of the stilling basin showed the highest percentage of reduction in scour depth equal to 80% of the value observed in the control test. Also,this method had a better performance in reducing the scouring depth of the taillwater stilling basin of the masonary check dam in order to create the greatest amount of erosion at a distance far from the stilling basin.