Flow Pattern at Sand Pocket

Sand pocket as one of the sediment control structures such as Sabo dam, check dam, consolidation dam, has a very important role to protect the dam site. Sand pocket located at the downstream near the dam and also as the location of sand mining. In Bili-Bili dam system, there are 5 (five) units, sand pocket, but all of the structures, have been collapsed after the gigantic caldera of mount Bawakaraeng collapse At March, 2004. This experimental study shown that the capacity of the sand pocket is enough for the design discharge to flow through the opening of the sand pocket, and the hydraulic jump not happened at the stilling basin, but at the down stream of the sand pocket. And this caused depth scouring about 3, 50 6 metres