Integrated Hydrological–Hydraulic Framework for Urban Flood Risk Management in Montería, Colombia: From 2D Modeling and Vulnerability Assessment to Structural, Non-Structural, and Emergency Intervention Measures

Tropical mid-size cities on alluvial floodplains face compounded flood challenges com-bining pluvial accumulation from intense convective storms, regulated river overflow, and aging drainage networks. This study presents an integrated framework for Mon-teria, Colombia (~450,000 inhabitants; Sinu River, Caribbean lowlands), within Colom-bian Decree 1807/2014 and structured in four phases. (1) Hazard: a Rain-on-Grid 2D HEC-RAS 6.6 model covering 4,090 ha, calibrated against four gauged events, identifies three dominant pluvial mechanisms (poor hydraulic connectivity, limited evacuation capacity, downstream channel overflow), plus 17 critical fluvial erosion points affecting ~289 properties at 100-year return period. (2) Vulnerability: depth-damage functions from 1,465 household surveys yield 36.36% of 3,015 assets in high risk, 57.77% in medium risk. (3) Measures: scenario M2 (channel widening plus dikes, land-raising, retention lagoons) removes 80 ha of flooding while displacing 28 ha at COP 845 million pre-design cost. Non-structural measures include a Sustainable Urban Drainage Master Plan, IoT-based Early Warning System, minimum construction-elevation map, and land-management instruments. A Monte Carlo residual-risk model reduces baseline risk to 19.9% under full implementation. (4) Emergency: a February 2026 cold-front event was addressed with a 4,300 m perimeter dike and six pump stations deployed jointly by the Regional Environmental Authority (CVS) and Municipal Administration.