Analisis debit banjir menggunakan data hujan satelit pada sub-DAS Brantas Hulu Jawa Timur

Abstract

Extreme rainfall can result in increased water discharge in the river that exceeds the capacity of the river and can cause flooding throughout the river as often happens in the Brantas River. One of the efforts to minimize the risk is by predicting flood discharge for future events using rainfall data. However, observed rainfall records are often incomplete, so satellite-based rainfall data is used as an alternative. This research will discuss the analysis of the comparison between observed rainfall and satellite-based rainfall from GPM-IMERG, PERSIANN, and GSMaP to find the best correlation between observed rainfall data and satellite-based rainfall data used to find the design flood discharge from satellite-based rainfall data. The method used in this research is the Nakayasu Synthetic Unit Hydrograph combined with effective rainfall calculated using the SCS-CN method to obtain the results of flood hydrographs in the Brantas Hulu Subwatershed. The results show that GPM-IMERG data has the strongest correlation with observed rainfall data with r= 0,48, indicating it can be used to calculate the design flood discharge, which produced a peak discharge value of 1632.99 m³/s for a 25-years return period.