STUDY OF FLOOD CONTROL AND MORPHOLOGY OF THE SARIO RIVER IN MANADO CITY

• Main Author: Rofiano Lombogia, Davidson
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/62658
• Institution: Institut Teknologi Bandung

Sario River is located in Manado City, North Sulawesi Province, Sario River is one of the rivers that contribute to flooding in Manado City. Floods that occurred in Manado City in 2014, 2017, 2019 and 2021 resulted in a lot of loss and damage to community facilities and infrastructure, as well as paralyzing residents' activities. Floods that occur are caused by high rainfall, conversion of land in the upstream part, silting occurs due to sedimentation and garbage, as well as river narrowing due to the occupation of people around the riverbanks. Because the condition of the Sario River downstream is very densely populated due to residents' occupations, in this study the solution offered for flood control, especially in the downstream Sario River, is by building a by-pass channel under the road that is directly directed to the sea, considering the liberation land for the construction of the embankment still cannot be implemented and requires a long process. The construction of this bypass channel aims to minimize flood discharge in the downstream area of the Sario River. The by-pass channel under this road will drain some of the water discharge in the Sario River during the Q25 flood discharge, which is 223.18 m³/sec. The methodology used in this study is hydrological analysis and hydraulic analysis and sedimentation analysis. Hydrological analysis was carried out to calculate the design flood discharge, and hydraulic analysis using the HEC-RAS 6.1 1D software using cross-sectional data from the Sario River. This study will simulate the water level and discharge after the construction of the by-pass channel under the road, as well as the agradation and degradation that occurs in the Sario River. Based on hydraulic analysis, the construction of a by-pass channel can reduce flood discharge in the downstream of the river, which is around 65.35%. And from the results of the study it was also found that for the research location there was sedimentation in several sections so that handling was needed, namely by normalizing or dredging the riverbed. Normalization is carried out every year to minimize sedimentation that occurs in the Sario River.