Flood Control Structure (Canal) in River Basin of Air Bengkulu River

Abstract

The Air Bengkulu River Basin experiences a frequency of flooding twice a year due to the increase in water discharge during the rainy season. The purpose of this study is to determine the amount of peak discharge of the Air Bengkulu River and to know how to plan dimensions of floodway control buildings in the Air Bengkulu River Basin. Rainfall data used in the purposes of this study are rainfall data for the last 10 years (2010-2019). Regional rainfall analysis is calculated using the maximum data method (annual maximum series). Rainfall analysis plans calculated by statistical methods. The analysis of the planned flood peak discharge was calculated using the Nakayasu Synthetic Unit Hydrograph method with the results of the peak discharge of the Air Bengkulu River for the 2nd, 5th, 10th, 20th, 25th, 50th and 100th year anniversary periods, respectively 557.68 m3/s; 732.85 m3/s; 845.18 m3/s; 955.15 m3/s; 978.80 m3/s; 1074.35 m3/s; and 1166.71 m3/s. Flood canal design analysis is calculated using the manning equation method (try error) using a return period of 25 years with a discharge of 955.15 m3/s; circular canal with a cross-sectional diameter of 18.5 m; with a water level of 14.68 m and a height of 3.82 m; while the canal is square in shape with a base width of 25 m; water level of 5.55 m; and height of 1.45 m guard; able to accommodate the debit plan return period of 25 years.