PEMODELAN NUMERIK UNTUK MENENTUKAN DEBIT BANJIR DAS BAYANG KABUPATEN PESISIR SELATAN

Abstract

 The research aims : 1) analysis hydraulic model in numeric modeling of flow Bayang watershed, 2) modeling spatial flood of Bayang watershed using HEC-RAS. Type thi research uses quantitative method with spatial approach. The data used for flood discharge is maximum rainfall in 2013-2022. Data were analysis using unsteady flow technique with software HEC-RAS and literature study. 1) The study produces 100 year periode discharge with a peak time of 1.27 hours which produces a period 2 year of 263.98 m³/sec, period 5 of 303.08 m³/sec, period 10 of 328.95 m³/sec, period 25 of 361.70 m³/sec, period 50 of 385.95 m³/sec and period 100 0f 410.07 m³/sec. 2) The model produce 1-D and 2-D models, the 1-D model produc a flood overflow depth of 3.03 to 1.71 meters while the 2-D model produce a flood overflow depth of 3 to 2 meters, villages of Sawah Laweh, Pasar Baru, Talaok, and Koto Barapak.