Evaluasi kapasitas Sungai Gendol Yogyakarta

Abstract

Gendol River is one of the rivers in the Yogyakarta region and is a tributary of the Opak River. During the rainy season, the Gendol River sometimes overflows at several points, as happened in the Jambon area. The overflow that occurs due to river discharge exceeds the capacity of the river, causing inundation. Based on these problems, a study was conducted on the analysis of the capacity of the Gendol River to determine the possibility of flooding and the locations that experienced flooding. So that countermeasures can be taken to prevent or minimize the impact that occurs. The design rainfall analysis uses the Pearson III Log tested by Chi Square and Smirnov Kolmogorof. Rain distribution analysis uses the Alternating Block Method (ABM) rain distribution method. Synthetic unit hydrograph obtained with Nakayasu. River hydraulics analysis is using HEC-RAS software. The results of the analysis of the design flood discharge that occurred in the Gendol River for return periods of 2, 5, 10 and 20 years were 60,770 m3 /s, 72,014 m3 /s, 79,092 m3 /s, and 84,761 m3 /s. The results of the comparison between the design flood discharge and the capacity of the Gendol River can be concluded that the river can still accommodate a 20-year design discharge. For the possibility of overflow caused by the flood discharge of the Gendol River exceeding the return period of 20 years or other factors.