Kajian Mitigasi Banjir Sungai Rongkong Di Kabupaten Luwu Utara

Abstract

The Rongkong River, located in North Luwu Regency, is known for causing annual floods. The upstream region, characterized by mountainous terrain, results in a steep riverbed slope, leading to swift currents and substantial sediment transport. Sediments accumulate in the midstream and downstream sections, causing frequent floods due to the river's limited capacity to handle high discharge. To mitigate these flood disasters, an early warning system is being implemented. By monitoring the upstream water level, flood occurrences downstream, especially near residential areas, can be estimated. Flood discharge calculations are performed using HEC-HMS 4.9 software, and flood propagation is assessed using HEC-RAS 6.0 software. Propagation times for different flood levels (Q2, Q5, Q10, and Q20) from upstream to downstream range from 4.5 to 10 hours. The early warning system comprises three levels: "ready" "standby" and "watch out" In Pangkedekan, Beringin Jaya, and Lembang Lembang Villages, the transition from the prepared level to the warning level is rapid, taking only 0.5 to 1 hour. In Sabbang Village, this transition can take from 1 to 9.25 hours.