Electronic Theses and Dissertation

Sungai memiliki kapasitas tersendiri untuk menampung air di dalamnya, jika terjadi curah hujan yang tinggi maka debit air di badan sungai akan meningkat. Peningkatan debit air mengakibatkan terjadinya penggenangan banjir akibat limpasan air dari sungai. Daerah Aliran Sungai (DAS) Krueng Keureuto yang terletak di Kabupaten Aceh Utara merupakan DAS yang sering mengalami banjir setiap tahun. DAS Krueng Keureuto sendiri memiliki beberapa Sub DAS, salah satunya adalah Sub DAS Krueng Peuto yang dialiri oleh Sungai Krueng Peuto. Pada akhir tahun 2021, terjadi jebol tanggul pada aliran Sungai Krueng Peuto. Jebolnya tanggul tersebut menyebabkan air sungai meluap dan merendam ratusan rumah di 33 desa yang tersebar di enam kecamatan sekitar Sub DAS. Penelitian ini bertujuan untuk menganalisis pengembangan model hidrodinamis 2D dan validasi titik sebaran banjir di Sub DAS Krueng Peuto berdasarkan banjir historis menggunakan software Geo-HECRAS, serta mengetahui detail kondisi banjir (kedalaman dan luas genangan banjir) berdasarkan hasil pemodelan untuk periode ulang 2, 5, 10, 25, 50, dan 100 tahun. Dari hasil pemodelan didapatkan luas genangan banjir pada periode ulang 25 tahun seluas 25,514 km2. Kedalaman banjir pada periode ulang 25 tahun untuk kedalaman 0-1 m seluas 8,35 km2 (32,73%), kedalaman 1-2 m seluas 6,71 km2 (26,33%), dan kedalaman >2 m seluas 10,44 km2 (40,95%). Hasil validasi genangan banjir periode ulang 25 tahun dengan titik sebaran banjir menunjukkan 17 titik (81%) berada di area genangan banjir, dan 4 tidak berada di area genangan banjir.

The river has its own capacity to hold water in it, if there is high rainfall, the water discharge in the river body will increase. The increase of water discharge caused flood inundation due to water runoff from the river. The Krueng Keureuto watershed located in North Aceh Regency is a watershed that often experiences flooding every year. The Krueng Keureuto watershed itself has several sub-watersheds, one of which is the Krueng Peuto sub-watershed which is fed by the Krueng Peuto River. At the end of 2021, an embankment broke on the Krueng Peuto River. The embankment break caused river water to overflow and submerged hundreds of houses in 33 villages that spread across six sub-districts around the sub-watershed. This study aims to analyze the development of 2D hydrodynamic model and validation of flood distribution points in Krueng Peuto Subwatershed based on historical floods using Geo-HECRAS software, and find out details of flood conditions (depth and area of flood inundation) based on modeling results for return periods of 2, 5, 10, 25, 50, and 100 years. From the modeling results, it was found that the flood inundation area at the 25-year return period was 25.514 km2. Flood depth in the 25-year return period for a depth of 0-1 m covering an area of 8.35 km2 (32.73%), a depth of 1-2 m covering an area of 6.71 km2 (26.33%), and a depth of >2 m covering an area of 10, 44 km2 (40.95%). The validation results of the 25-year return period flood inundation with flood distribution points show that 17 points (81%) are located in the in the flood inundation area, and 4 are not in the flood inundation area.