Designing conduit sabo dam series as a debris flow protection structure

¹ Department of Civil and Environmental Engineering, Gadjah Mada University, 55281 Yogyakarta, Indonesia
² Department of Geological Engineering, Gadjah Mada University, 55281 Yogyakarta, Indonesia
³ Center of Excellence for Disaster Mitigation and Technological Innovation, Gadjah Mada University, 55281 Yogyakarta, Indonesia

^* Corresponding author: della.a.l@eng.ugm.ac.id

Abstract

A high potential area for landslides was identified upstream of the Air Beras River on Bukit Beriti Besar which was feared to generate debris flow through the Air Beras River. One of the preventive efforts that can be conducted for debris flow is the sabo dam. This study aims to design a series of conduit sabo dams and evaluate the structure stability according to SNI 2851:2015 and Technical Standards and Guidelines for Planning and Design of Sabo Structures (JICA, 2010). By using the design discharge of debris flow of 120 m3/s, the velocity of 5.06 m/s, and the inclination of the riverbed of around 6.16°, the spillway height of the Sabo Dam 1 was determined to be 3 m, while the spillway height of Sabo Dam 1 was 2 m. The Sabo Dam 1 has a height of 10 m and a width of 30 m with a total manageable volume of 49,600 m3 while the Sabo Dam 2 has a height of 10 m and a width of 45 m with a total manageable volume of 91,500 m3. The safety factors of the sabo dam in the debris flow condition were 2.14 for overturning, 1.50 for sliding, and 5.74 for bearing capacity. Based on the result, the conduit sabo dam series effectively controls the destructive power of debris flow.