Development of a community-oriented decision support tool for compound flood events in the US

Published: 27 August 2020

The US Department of Homeland Security (DHS) Science and Technology Directorate (S&T) has partnered with Deltares USA and Deltares, to develop a community-oriented, flood hazard modeling and impact assessment decision support tool for compound flood events, using open source data, models, and software. This contract helps address the Federal Emergency Management Agency’s goal of building a culture of preparedness across the United States, as reducing flood fatalities and property losses from flood disasters is a significant concern.

Improved information on flood risks

This project with Deltares USA will develop and demonstrate a process and prototype configuration using freely available Deltares software, such as Delft Dashboard, SFINCS and Delft-FIAT, and provide communities with the capabilities necessary to develop planning strategies to improve resilience to compound flood events. With this improved information on flood risks, this project provides the potential to increase flood insurance uptake and drive additional mitigation investments needed to lower risk.

Combined flooding sources

Compound flood events result from a combination of rain driven inland flooding and storm surge flooding. These types of flood events are particularly devastating to communities because of the combined flooding sources. The complex and unpredictable nature of severe weather is a challenge to developing a plan to protect a community from flooding.

Flooding is one of the United States’ and the world’s most costly and frequent disasters. Dr. Ap van Dongeren, Senior Specialist at Deltares says: “With research partners, Deltares is continuously improving its flood and damage modelling, making it more accurate and faster. By combining the effects of storm surge from the ocean, rainfall and river discharges, we can now assess the risk of compound flooding. And with SFINCS, flood computations for hurricane conditions take just minutes, which means that we can explore the effect of variations in the hurricane track and intensity by running the model 100s of times. We are excited to further develop and apply our models in this project.”

Defining stakeholders’ needs

The project’s work will begin with a workshop for community and DHS stakeholders to examine and define needs, capabilities and desired outcomes. Information gathered at the workshop will inform process model development, and that model will be validated against historical events and hypothetical storm scenarios using Deltares open source software, in addition to being tested against a prototype configuration. The process model and prototype configuration will be fine tuned to ensure that they operate and produce outcomes consistent with the intended project goals. The project will begin FY2020 and continue through FY2021.