Electronic Theses and Dissertation

Banjir merupakan fenomena luapan air yang menutupi daratan dan menimbulkan berbagai kerugian, baik dari aspek sosial, ekonomi, lingkungan, hingga keselamatan manusia. Kabupaten Aceh Selatan, khususnya wilayah pesisir Trumon, memiliki curah hujan tinggi dan kondisi topografi yang bervariasi sehingga rentan mengalami banjir. Oleh karena itu, diperlukan upaya mitigasi berupa pembangunan tampungan banjir sementara sebagai solusi penanganan banjir. Penelitian ini bertujuan untuk mendeteksi daerah rawan banjir, menentukan lokasi yang paling sesuai untuk pembangunan tampungan banjir sementara, serta menghitung kapasitas tampungan yang dapat ditampung pada wilayah pesisir Trumon, Aceh Selatan. Analisis kerawanan banjir dilakukan dengan mempertimbangkan curah hujan, elevasi, jenis tanah, penggunaan lahan, dan jarak dari sungai. Untuk potensi kolam retensi didapatkan dengan mengambil nilai TWI > 8,0. Selanjutnya, metode Multi Criteria Decision Making (MCDM) melalui pendekatan Analytical Hierarchy Process (AHP) digunakan untuk penentuan lokasi kolam retensi berdasarkan parameter penggunaan lahan, jenis tanah, jarak sungai, dan kepemilikan lahan. Seluruh analisis spasial dilakukan menggunakan perangkat lunak ArcGIS. Hasil penelitian menujukkan bahwa daerah dengan kerawanan banjir sangat tinggi berada di sekitar 500 m dari sungai sedangkan dengan kerawanan sedang berada pada hutan rawa pada sisi selatan DAS Trumon. Selanjutnya lokasi tampungan banjir yang cocok untuk dibangun untuk mencegah banjir pada DAS Trumon sangat beragam dan ditinjau dengan melihat TWI sebagai tampungan alami. Adapun kapasitas total tampungan banjir yang tersebar pada beberapa titik DAS Trumon yaitu 20.792.113,71 m3.
Kata kunci: Banjir, TWIRDALS, MCDM, AHP, Tampungan banjir, ArcGIS, Trumon Aceh Selatan

Flooding is a phenomenon in which water overflows and covers land, causing various losses—social, economic, environmental, and to human safety. South Aceh Regency, particularly the Trumon coastal area, experiences high rainfall and varied topography, making it prone to flooding. Therefore, mitigation efforts are needed in the form of constructing temporary flood retention basins as a solution for managing and controlling runoff. This study aims to identify flood-prone areas, determine the most suitable locations for the construction of temporary flood retention basins, and calculate the storage capacity required for the Trumon coastal area in South Aceh. Flood vulnerability analysis was conducted by considering rainfall, elevation, soil type, land use, and distance from the river. The potential for retention ponds was determined by selecting areas with a TWI value > 8.0. Subsequently, the Multi-Criteria Decision Making (MCDM) method, using the Analytical Hierarchy Process (AHP) approach, was employed to determine retention pond locations based on parameters such as land use, soil type, distance from the river, and land ownership. All spatial analyses were performed using ArcGIS software. The research results indicate that areas with very high flood risk are located approximately 500 m from the river, while those with moderate risk are found in the peat swamp forest on the southern side of the Trumon Watershed. Furthermore, suitable locations for flood retention basins to be constructed to prevent flooding in the Trumon Watershed are highly varied and were evaluated by examining the TWI to minimize costs. The total flood storage capacity spread across several points in the Trumon Watershed is 20,792,113.71 m³. Keywords: Flood, TWIRDALS, MCDM, AHP, Flood storage, ArcGIS, Trumon South Aceh