A simple framework for calibrating hydraulic flood inundation models using Crowd-sourced water levels

•Framework for flood model calibration using crowd-sourced data with unknown timings.•Simulated and crowd-sourced maximum water levels inter-compared for calibration.•Relative value proposition of crowd-sourced data versus gauge data demonstrated.•Even limited & uncertain crowd-sourced points proved valuable for model calibration.•Crowd-sourcing can complement gauges for model calibration in data scarce regions.