Analisis Area Luapan Banjir Akibat Kenaikan Debit Air Berbasis Sistem Informasi Geografis (Studi Kasus : DAS Banjir Kanal Timur Kota Semarang)

Semarang is one of the areas in Indonesia that are prone to catastrophic flooding. This condition is getting worse with a decrease in land / land subsidence and the phenomenon of Rob(tide and gauge flood). In addition, an increase in water discharge that occurs during the rainy season, causing flooding along the Banjir Kanal Timur.Study using ArcGIS software version 10 to find out the distribution of flood area and HEC-RAS hydraulics simulation for hydraulics simulation.The technique used is to model the geometry of rivers and form a model based on the hydraulics contours and transverse cross section of the river that had spread in the flood overflow area. Analysis unsteady flow used for making maps of discharge flood plan 5, 10, and 25 years.From the results of research in the area of the largest flood overflow is Kecamatan Genuk Terboyo Kulon Village, on flood discharge plan 5, 10, and 25 years of successive became one of 116,449 Ha, 117,520 Ha, and 119,153 Ha. Land use is the largest flood affected farm with an area of 217,128 Ha, respectively, 218,851 Ha, and 221,116 Ha. Results of the flood overflow areas presented in the overflow area flood maps and overflow area flood maps on land use of discharge flood plan 5, 10, and 25 years