ANALISIS LUAS GENANGAN BANJIR MENGGUNAKAN HEC-RAS PADA DAERAH BENA AKIBAT LUAPAN SUNGAI NOELMINA KABUPATEN TIMOR TENGAH SELATAN - Yakob A Basen; Wilhelmus Bunganaen; John H Frans (Teodolita: Media Komunkasi Ilmiah di Bidang Teknik, 2025)
Abstrak Bena merupakan salah satu desa di Kecamatan Amanuban Selatan, Kabupaten Timor Tengah Selatan, Provinsi Nusa Tenggara Timur yang terdampak beberapa kali banjir sejak tahun 2021 sampai 2024 akibat luapan sungai Noelmina. Penelitian ini menganalisis luas genangan banjir yang terjadi menggunakan aplikasi HEC-RAS. Analisis luas genangan banjir yaitu mengetahui berapa luas genangan banjir yang terjadi disetiap kala ulang. Analisis curah hujan yang digunakan dalam penulisan ini yaitu distribusi normal, distribusi log normal, distribusi gumbel, dan distribusi log person type III, uji keco-cokan distribusi menggunakan chi-kuadrat dan Smirnov Kolmogorov untuk debit banjir yang menggunakan HSS Nakayasu dengan kala ulang 2, 5, 10, 25, 50, 100, 200, 300, 500 tahun. Luasan banjir dianalisis dengan aplikasi HEC-RAS kemudian di overlay dengan batas administrasi desa Bena di aplikasi Arc-Gis untuk mendapatkan berapa besar luasan banjir di desa Bena. Hasil luas banjir kala ulang 2, 5, 10, 25, 50, 100, 200, 300, 500 di dapat sebesar 20.59 km2, 25.64 km2, 30.52 km2, 37.11 km2, 41.56 km2, 44.66 km2, 46.93 km2, 47.56 km2, 49.03 km2. Kata kunci: Analisis Luapan Banjir, HEC-RAS Abstract Bena is a village in the South Amanuban District, South Central Timor Regency, East Nusa Tenggara Province, which was affected by several floods from 2021 to 2024 due to the overflow of the Noelmina River. This study analyzed the extent of flood inundation that occurred using the HEC-RAS application. The analysis of the extent of flood inundation is to find out how much flood inundation occurs at each re-turn period. The rainfall analysis used in this paper is the normal distribution, log normal distribution, gumbel distribution, and log person type III distribution, the distribution goodness of fit test uses chi-square and Smirnov Kolmogorov for flood discharge using HSS Nakayasu with return periods of 2, 5, 10, 25, 50, 100, 200, 300, 500 years. The flood area was analyzed using the HEC-RAS application and then overlaid with the administrative boundaries of Bena village in the Arc-Gis application to obtain the extent of flooding in Bena village. The results of the flood area for return periods of 2, 5, 10, 25, 50, 100, 200, 300, 500 were 20.59 km2, 25.64 km2, 30.52 km2, 37.11 km2, 41.56 km2, 44.66 km2, 46.93 km2, 47.56 km2, 49.03 km2. Keywords: Flood Overflow Analysis, HEC-RAS