RESTORATION ANALYSIS OF KURANJI DAM DUE TO SCOURING AT THE DOWNSTREAM

Sub-dam at downstream of the Gunung Nago Main-dam at Kuranji river in Padang had suffered from severely damage during the flash flood on July 24, 2012. The flood known as 'Galodo' by local people has lead to the scouring at the downstream of the Gunung Nago sub-dam. The scouring was deep and long enough to cause the tail structure of that stone masonry dam suffered from damaged. The damage resulted in malfunction of the dam then needs the restoration work. Besides protecting the main dam, this sub-dam is also used as intake to take irrigation water and drinking water for the right side of the downstream area of the Kuranji river. This paper explains the mechanical analyses to set up the idea of the reparation method the damaged dam. Based on the results of the study, this dam can be repaired without the use of reinforced concrete material. So that simple improvement can be done by filling back the scoured foundation and constructing back with the use of stone masonry materials. To protect against the future scouring this restoration is completed with an apron structure at the downstream of the dam. This study is very useful to design and construction of the small dam in general. In case of restoration it can carry out the reparation work quickly and cheaply.