IHST (Integrated, Holistic, Spatial, and Thematic) Flood Management Model: The Integration of Flood Model, Green Infrastructure and Non-Structural Mitigation in the Urban Area of Barabai City

The January 2021 Floods paralyzed the entire Hulu Sungai Tengah Region, South Kalimantan Province, Indonesia, submerging 20,553 houses, causing minor damage to 2,973 houses, severe damage to 268 houses, and resulting in losses exceeding 53 million dollars. The Barabai Urban Area was one of the locations severely affected by flood. The flood management was conducted in the Barabai urban area to predict and visualize water movement during flooding, aiding in understanding and mitigating flood risks, as well as developing effective flood management strategies. The flood management was carried out adopted the IHST Model, which is the abbreviation from Integrated, Holistic, Spatial, and Thematic. The activities involve HECRAS 6.2 application, utilizing Google Earth terrain data, river geometry data, and flood discharge analysis based on the Nakayasu method. The analysis results highlighted the need for both structural and non-structural flood interventions. Non-structural interventions aiming to reduce vulnerability and enhance community capacity in facing flood. Structural developments involved the construction of storm water retention ponds and river embankments at specific locations based on the flood modelling results. The concept of polder and river embankment development was approached through green infrastructure principles, as flood management solutions should not only facilitate rapid water drainage but also improve soil absorption to prevent prolonged inundation.