A comprehensive web-based system for flood inundation map generation and comparative analysis based on height above nearest drainage.

It is critical to obtain accurate flood extent predictions in a timely manner in order to reduce flood-related casualties and economic losses from floods with greater magnitudes and fall outside the handling capacity of our existing mitigation systems. Running a real-time flood inundation mapping model is helpful in supporting quick response decisions for unplanned floods, such as how to distribute limited resources and labor so that the most flood-prone areas receive adequate mitigation efforts and how to execute evacuations that keep people safe while causing the least amount of unneeded disruption. Most inundation systems, on the other hand, are either overly demanding in terms of data and computing power or have limited interaction and customization with various input and model configurations. This paper describes a client-side web-based real-time inundation mapping system based on the Height Above the Nearest Drainage (HAND) model. The system includes tools for hydro-conditioning terrain data, modifying terrain data, custom inundation mapping, online model performance evaluation, and hydro-spatial analyses. Instead of only being able to work on a few preprocessed datasets, the system is ready to run in any region of the world with limited data needs (i.e., elevation). With the system's multi-depth inundation mapping approach, we can use water depth measurements (sensor-based or crowdsourced) or model predictions to generate more accurate flood inundation maps based on current or future conditions. All of the system's functions can be performed entirely through a client-side web browser, without the need for GIS software or server-side computing. For decision-makers and the general public with limited technical backgrounds, the system provides a one-stop, easy-to-use flood inundation modeling and analysis tool.