Analisis Kondisi Banjir di Kampus USU Berbasis Hecras dan GIS

Abstract

Floods are one of the natural disasters that often hit various regions in the country, causing not a few casualties and financial losses, damaging public facilities and disrupting socio-economic activities experienced by disaster victims. This is due to the drainage conditions at the USU Campus with an area of ±143 Ha where some of the channels on the USU Campus which appear unable to accommodate the amount of incoming discharge either due to a smaller capacity than the existing discharge, lack of maintenance and drainage systems and disposal that is no longer suitable for the environment and so on. This study aims to obtain and determine the potential for flood inundation in the USU Campus Area with a flood inundation map generated from the modeling of the flood inundation map resulting from the integration of the Hydrologic Engineering Center-River Analysis (HECRAS) software with the Geographic Information System (GIS). In conducting this study, data were collected which included topographic data and data on the state of the drainage area of the USU Campus, rainfall data from the BMKG, land use data, and LIDAR topographic data. The Log Person III method fulfills the requirements for distribution of rainfall frequency distribution. Furthermore, periodic flood discharge calculations are carried out using the Rational Method for flood return periods of 1, 2, 5, 10, 20, 25, 50, and 100 years. From the results of the flood inundation analysis using Lidar topography data, it can be seen that the difference in inundation heights from the simulation results carried out on the drainage of the USU Campus Area and the simulation after the addition of the discharge from the Babura River which is connected to become a single unit of drainage network, the flood height becomes higher around the outlet to the river. Several locations of floods that occurred on the USU Campus were University Street starting from the front of the Student Center to the intersection of Jalan Dr. Mansur, Along Jalan Dr. Mansur, the Polytechnic Lecture Building to the intersection of Jalan Dr. Mansyur, Faculty of Public Health, Faculty of Law.

Banjir merupakan salah satu bencana alam yang sering melanda berbagai daerah-daerah di dalam negeri, yang menimbulkan tak sedikit korban jiwa dan kerugian finansial, merusak fasilitas-fasilitas umum dan mengganggu aktivitasaktivitas social-ekonomi yang dialami oleh para korban bencana.Penelitian ini dilatarbelakangi oleh kondisi drainase di Kampus USU dengan luas lahan ±143 Ha di mana sebagian dari saluran yang ada di Kampus USU yang terlihat tidak mampu menampung besarnya debit yang masuk baik disebabkan oleh daya tampung yang lebih kecil dari debit yang ada, kurangnya perawatan maupun sistem pengaliran dan pembuangan yang tidak sesuai lagi dengan lingkungan dan sebagainya. Studi ini bertujuan untuk memperoleh dan mengetahui potensi genangan banjir di Kawasan Kampus USU dengan peta genangan banjir yang dihasilkan dari pemodelan peta genangan banjir hasil dari integrasi antara software Hydrologic Engineering Center-River Analysis (HECRAS) dengan Geografic Information System (GIS). Dalam melakukan studi ini dilakukan pengumpulan data yang mencakup data topografi dan data keadaan daerah aliran drainase Kampus USU, data curah hujan dari BMKG, data tata guna lahan, dann data Topografi LIDAR. Metode Log Person III memenuhi syarat agihan distribusi frekensi curah hujan.Selanjutnya dilakukan perhitungan debit banjir periodik menggunakan Metode Rasional untuk kala ulang banjir 1, 2, 5, 10, 20, 25, 50, dan 100 tahun. Dari hasil analisis genangan banjir menggunakan data Topografi Lidar terlihat perbedaan ketinggian genangan dari hasil simulasi yang dilakukan terhadap drainase Kawasan Kampus USU lebih tinggi disekitar outlet menuju sungai. Beberapa lokasi banjir yang terjadi di Kampus USUadalah Jalan Universitas mulai dari depan Gelanggang Mahasiswa sampai persimpangan Jalan Dr. Mansur, Sepanjang Jalan Dr. Mansur, Fakultas Kesehatan Masyarakat, Fakultas Hukum.