Electronic Theses and Dissertation

Banjir merupakan masalah tahunan di Daerah Aliran Sungai Peusangan, Aceh. Banjir akibat luapan Sungai Peusangan ini berdampak pada kerusakan lingkungan serta kerugian ekonomi yang besar bagi masyarakat setempat, terutama di bagian hilir. Sebagai upaya mitigasi terhadap dampak tersebut, diperlukan langkah pengendalian banjir guna memangkas puncak banjir. Tujuan penelitian ini ialah menetapkan lokasi kolam retensi dan normalisasi serta mengetahui pengaruhnya terhadap luas genangan dan ketinggian muka air banjir. Untuk mendukung perencanaan tersebut, penelitian ini menggunakan software Hydrologic Engineering Centers River Analysis System (HEC-RAS) 2D dalam merencanakan pemodelan bangunan pengendali banjir. Pemodelan dilakukan dengan merancang sebelas unit kolam retensi serta pelaksanaan normalisasi sungai di tiga lokasi. Kapasitas total tampungan kolam retensi ialah sebesar 192.743.450 m3. Sementara itu, pelaksanaan normalisasi sungai dilakukan di tiga lokasi dengan panjang masing-masing sebesar 2.130 meter, 1.794 meter, dan 1.596 meter. Hasil pemodelan menunjukkan bahwa luas wilayah desa terdampak banjir sebelum adanya bangunan pengendali sebesar 30,359 km². Setelah dilakukan penanganan melalui skenario pembangunan kolam retensi, normalisasi sungai, serta kombinasi keduanya, luas genangan mengalami penurunan berturut-turut menjadi 18,843 km², 29,265 km², dan 17,310 km². Hal ini menunjukkan terjadinya penurunan luas desa terdampak banjir berturut-turut sebesar 10%, 15%, dan 9% dibandingkan kondisi awal sebesar 16%. Tinggi muka air pada skenario kolam retensi serta kombinasi kolam retensi dan normalisasi mengalami penurunan dari 1,39 meter menjadi 0 meter. Sedangkan pada skenario normalisasi sungai, WSE menurun menjadi 1,19 meter.

Flooding is an annual problem in the Peusangan River Basin, Aceh. Flooding due to overflowing Peusangan River has an impact on environmental damage and major economic losses for local communities, especially in the downstream areas. As an effort to mitigate these impacts, flood control measures are needed to reduce the peak of the flood. The purpose of this study was to determine the location of retention and normalization ponds and to determine their effects on the area of inundation and height of the flood water level. To support this planning, this study used software Hydrologic Engineering Centers River Analysis System (HEC-RAS) 2D in planning flood control building modeling. Modeling was carried out by designing eleven retention pond units and implementing river normalization in three locations. The total capacity of the retention pond is 192.743.450 m3. Meanwhile, the implementation of river normalization was carried out in three locations with lengths of 2.130 meters, 1.794 meters, and 1.596 meters respectively. The modeling results show that the area of the village affected by the flood before the control building was 30,359 km². After handling through the retention pond construction scenario, river normalization, and a combination of both, the inundation area decreased successively to 18,843 km², 29,265 km², and 17,310 km². This shows a decrease in the area of the village affected by the flood by 10%, 15%, and 9% respectively compared to the initial condition of 16%. The water level in the retention pond scenario and the combination of retention ponds and normalization decreased from 1,39 meters to 0 meters. Meanwhile, in the river normalization scenario, the WSE decreased to 1,19 meters.