Electronic Theses and Dissertation

Menurut data dari dinas pengairan aceh, wilayah hilir daerah aliran sungai (das) peusangan sering kali mengalami kejadian banjir yang berdampak pada kerusakan lingkungan serta kerugian ekonomi yang besar. kejadian ini diakibatkan oleh beberapa faktor yang menjadi permasalahan di bagian hulu das peusangan yang terletak di kabupaten aceh tengah. untuk itu diperlukan penanganan baik secara struktural maupun nonstruktural. upaya penanganan banjir di daerah das peusangan yang sudah dilakukan ialah pembuatan tanggul penahan tanah. selain itu, perlu dilakukannya kajian terkait kondisi genangan yang terjadi, salah satunya dengan melakukan pemodelan genangan banjir menggunakan software hydrologic engineering centers river analysis system (hec-ras). pemodelan genangan banjir dilakukan dengan menggunakan model hec-ras 2d unsteady flow serta menggunakan software arcgis 10.5 untuk melakukan visualisasi daerah genangan dan area terdampak banjir. hasil nilai debit maksimum yang dihitung dengan menggunakan metode hidrograf satuan sintetis soil conservation service (hss scs) untuk tiap periode ulang 2, 5, 10, 25, 50, dan 100 tahun ialah berturut-turut sebesar 745,034 m³/det, 1350,276 m³/det, 1636,281 m³/det, 1898,347 m³/det, 2045,367 m³/det, dan 2160,576 m³/det. kemudian hasil dari pemodelan daerah genangan banjir menggunakan software hec-ras 2d unsteady flow ialah sebaran aliran dan wilayah yang tergenang banjir, serta luas genangan yang terjadi untuk setiap periode ulang 2, 5, 10, 25, 50, dan 100 tahun secara berturut-turut ialah sebesar 37,381 km², 78,127 km², 95,166 km², 112,819 km², 120,672 km², dan 126,285 km². hasil validasi pemodelan daerah genangan terhadap data titik sebaran banjir pada das peusangan didapatkan bahwa persentase genangan yang terjadi untuk tiap periode ulang 2, 5, 10, 25, 50, dan 100 tahun ialah berturut-turut sebesar 28,571%, 66,667%, 71,429%, 76,190%, 90,476%, dan 90,476%.

According to data from the Aceh Irrigation Service, the downstream areas of the Peusangan River Basin (DAS) often experience flooding events which result in environmental damage and large economic losses. This incident was caused by several factors which became problems in the upstream part of the Peusangan Watershed which is located in Central Aceh Regency. For this reason, both structural and non-structural treatment is needed. Efforts to deal with flooding in the Peusangan watershed area that have been carried out include the construction of earth-retaining embankments. Apart from that, it is necessary to carry out studies regarding the conditions of inundation that occur, one of which is by modeling flood inundation using software Hydrologic Engineering Centers River Analysis System (HEC-RAS). Flood inundation modeling was carried out using the 2D HEC-RAS model Unsteady flow as well as using software ArcGIS 10.5 to visualize inundated areas and areas affected by flooding. The maximum discharge value is calculated using the Unit Hydrograph method Sintetis Soil Conservation Service (HSS SCS) for each return period of 2, 5, 10, 25, 50, and 100 years is respectively 745,034 m³/sec, 1350,276 m³/sec, 1636,281 m³/sec, 1898,347 m³/ sec, 2045,367 m³/sec, and 2160,576 m³/sec. Then the results of modeling flood inundation areas using software HEC-RAS 2D unsteady flow namely the distribution of streams and areas inundated by floods, as well as the area of inundation that occurs for each return period of 2, 5, 10, 25, 50 and 100 years respectively, namely 37,381 km², 78,127 km², 95,166 km², 112,819 km², 120,672 km², and 126,285 km². The results of the validation of inundation area modeling on flood distribution point data in the Peusangan watershed showed that the percentage of inundation that occurred for each return period of 2, 5, 10, 25, 50 and 100 years was respectively 28,571%, 66,667%, 71,429%, 76,190%, 90,476%, and 90,476%.