ANALISIS DEBIT BANJIR DAN DINDING PENAHAN PADA HILIR SUNGAI NGOTOK DI KOTA MOJOKERTO

Abstract

The Ngotok River in Mojokerto City has a length of 25 km and an area of ​​269.87 km2 of watershed. At the downstream side of the riverbank, marine tourism and green open spaces will be built. This study aims to determine the discharge in the Ngotok River with a return period of 50 years and to anticipate overflows in the riverbank area. The data needed is Rainfall Data for 5 Rain Stations, namely Jombang, Kesamben, Sambiroto, Mojoagung and Terusan 2009 to 2018. Determining the correctness of rainfall data using the multiple mass curve method. In the design of rainfall planning using the algebraic average method while the regional rainfall planning uses the Log Pearson type 3 method. To strengthen the selection of the distribution taken using the Chi-square test distribution test and the Smirnov-Kolmogorov test. Furthermore, the planned flood discharge analysis was carried out using the HSS Nakayasu method. Based on the calculation, it was found that the flood discharge of Buntung River with a 50 year return period was 624,766 m3 / second. River improvement planning uses the HEC-RAS model with the results of overtopping areas at points P1-10, P40, P30, P14, P13, P5 and P2. The control building is a concrete sheet pile W-600 B.