ORIGINAL RESEARCH article
Front. Built Environ.
Sec. Urban Science
Volume 11 - 2025 | doi: 10.3389/fbuil.2025.1612416
This article is part of the Research TopicAdvances in Urban Flood Studies: Modeling, Monitoring, Strategic Planning, and Lessons LearnedView all articles
Identifying Dominant River Contributions to Urban Flooding: A Scenario-Based Study of Makassar City
Provisionally accepted
- 1Bandung Institute of Technology, Bandung, Indonesia
- 2Sumatra Institute of Technology, Lampung Selatan, Indonesia
- 3Gadjah Mada University, Yogyakarta, Special Region of Yogyakarta, Indonesia
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Makassar City, a fast-growing urban center in Eastern Indonesia, is highly vulnerable to flooding due to a combination of extreme rainfall, urban expansion, sedimentation, and a limited flood management system. This study investigates the main contributors to flooding in Makassar, based on the city's extreme flood event in January 2019 and evaluates the effectiveness of the Bili-Bili Reservoir in mitigating flood impacts through integrated hydrologic-hydrodynamic modeling. A combination of HEC-HMS and HEC-RAS 2D was used to simulate the rainfall runoff processes and model flood inundation. GSMaP satellite rainfall data, land cover, soil type, and topographic information (FABDEM+river cross-section) were integrated into the model. Additional terrain data from OSM-B highlights urban areas characterized by dense building development. The validation process was conducted by comparing the modeling output against the inundation maps provided by the local government. Scenario simulations with 20-year return period (Q20) discharges from the Tallo River, Jenelata River, and Bili-Bili Reservoir outflow were used to assess their individual and combined impacts on flooding. Findings indicate that the Tallo River is the dominant contributor to flooding, while reservoir releases and Jenelata River inflow triggered additional inundation in downstream areas. The Bili-Bili Reservoir reduced upstream flooding but was less effective under high-inflow conditions. Discrepancies between model results and reported flood extents in several districts suggest other contributing mechanisms, including urban drainage inadequacies. This study's findings emphasize the need for more targeted flood mitigation strategies, underscoring the importance of optimizing reservoir operations, managing sedimentation, and exploring storage interventions within Makassar City's river system to strengthen urban flood resilience.
Keywords: Flood modeling, Hydrologic simulation, Hydrodynamic simulation, HEC-HMS, HEC-RAS 2D, Makassar City, Riverine flooding
Received: 15 Apr 2025; Accepted: 19 Jun 2025.
Copyright: © 2025 Wulandari, Pratama, Andika, Wongso, Wijayasari and Rohmat. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Faizal Rohmat, Bandung Institute of Technology, Bandung, Indonesia
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