Integrating Flood Volume Metrics into Disaster Management: Development of an Integrated Hazard Map System in Korea

Modern disaster environments in Korea are increasingly characterized by compound hazards where excessive flood volume (runoff) interacts with slope instability and storm surge. Yet, traditional disaster management practices have treated flood depth or inundation extent in isolation, without explicitly incorporating real‑time flood volume estimates into decision support. This paper proposes and evaluates an Integrated Hazard Map System (IHMS) that prioritizes flood volume driven indicators alongside multi‑hazard layers. Leveraging the 2023 NDMI report on the "Advanced Utilization Framework for Integrated Hazard Maps"[1], the study develops (i) a centralized data repository aggregating hydrologic and geospatial layers from the Ministry of the Interior and Safety (MOIS), Korea Forest Service (KFS), and Korea Hydrographic & Oceanographic Agency (KHOA); (ii) an interoperable web‑service layer for continuous data exchange; and (iii) client applications equipped with analytics modules for scenario based simulations. Field scale demonstrations show that explicit flood‑volume thresholds better anticipate evacuation demand than depth only criteria, reducing false negatives by 23 percent. The IHMS can therefore enhance proactive, data driven disaster management in Korea and serve as a blueprint for other flood prone regions. Korea’s recent disasters are increasingly multi‑hazard events in which excessive flood‑volume runoff amplifies slope instability and coastal storm surge. However, conventional management systems still rely on flood‑depth or inundation extent alone and therefore overlook real‑time discharge information during decision making. We present an Integrated Hazard Map System (IHMS) that prioritises flood‑volume indicators alongside depth, landslide susceptibility and storm‑surge layers. IHMS consists of (i) a central repository that federates hydrologic and geospatial data from the Ministry of the Interior and Safety, Korea Forest Service and Korea Hydrographic & Oceanographic Agency; (ii) an OGC‑compliant web‑service layer that streams continuous updates; and (iii) browser‑ and mobile‑based clients equipped with scenario simulations. Field demonstrations during four major Korean flood events (2019–2022) show that adding a 1,000 m³ s⁻¹ discharge threshold reduces false‑negative alerts from 28 % to 5 % and extends average warning lead time by 42 min compared with depth‑only logic. Emergency‑operations‑centre trials (n = 27) yielded a System Usability Scale score of 86.2, indicating excellent operator acceptance. The IHMS framework therefore enables proactive, data‑driven disaster management and offers a transferable blueprint for other flood‑prone regions.