Experimental Investigation of Suction Pipe Holes Arrangement Effect on the Burrowing-type Dredging Method Performance

The reservoir sediment siphon dredging methods have been widely studied in recent decades. These methods do not have many disadvantages of other methods like extra energy consumption, reservoir operation interruption, water loss, releasing sediment with extra concentration. Sediment evacuation by burrowing type suction pipe method is an important method in which sediments are sucked through holes located at the bottom of the suction pipe, using only the potential difference of the reservoir upstream and downstream water levels. In this study the influence of pipe bottom holes extension is surveyed, using a 61 mm internal diameter pipe. The holes layouts consist of two holes diameters of 16 and 30 mm and three different spacing of holes. The results showed that the holes extension has a dramatic effect on the performance of the method, and, for both diameters, the method has its maximum performance if the holes are only located on the pipe bend part. Also, spacing of the hole affect the performance. Finally, the hole's layout with hole diameter of 30 and spacing of 90 mm with five bottom holes on the bend section has the maximum performance with average sediment concentration of 3.41 percent by volume.