Evaluasi kinerja dan pengambilan keputusan pemeliharaan rangkaian sabodam tahun 2023 di Kali Bebeng, Jawa Tengah

Abstract

After the 2010 Merapi eruption, there are still volcanic material deposits of around 70 m3 which have accumulated on the southern and western slopes, which have the potential for lava floods in the following years and cause high damage to water structures. It is known that 77 sabo dams built in rivers at Mount Merapi were damaged and were swept away by the lava flow (BBWS Serayu-Opak, 2011). Even though several damaged sabodams have been rebuilt, floods that cause damage still occur. Simultaneously with the increase in the current status of Mount Merapi to Level III Alert and monitoring of eruption activity with the potential for cold lava in the Bebeng river, research is needed that identifies and evaluates the current condition of these buildings so that appropriate maintenance decisions can be made. Field surveys and scoring are carried out through visual observations of sabodam, analysis of sabodam is based on the Sabodam Operation and Maintenance Guidelines (SE Ministry of PUPR no. 3 of 2019). As the results, there are 3 sabodams in the heavily damaged category, including BE-D4, BE-RD1A, and BE-D10. Broken subdams in the Bebeng River can generally be caused by 2 things, namely damage caused by the slope of the river bed which is still high about 11% and then there’s no structure to reduce falling material in the last sub dam which can erode the surrounding land to to the subdam foundation and the existence of mining activities near the building.