About

The FastFlood model is a free super-fast modelling tool focused on simulation of flood processes.

Authors

The main authors of the FastFlood model are:

Bastian van den Bout - [email protected]

For questions related to the website, model, or consulting, please contact B. van den Bout.

If you plan to use this work in scientific research, a citation to a recent article on the development of FastFlood would be appreciated.

History

The FastFlood method took shape in its first form around 2021. As part of the development of the LISEM model (https://www.lisemmodel.com), I was testing flow accumulation schemes that involved some sense of physics. Tools such as drainage networks (D8) or r.simwater provide a very useful way of structurally representing water flow in a fast and easy manner, but lose the representation of floodplains. In testing new versions of this, I noticed steady-state solvers with high initial water levels rapidly iterating to a flood-plain inclusive flow network. This helped in various types of models, such as soil depth predictors and wetness index. It was while explaining to a student how this worked I jokingly mentioned how it is actually a really good flood predictor that runs really fast. In the next year, I could spend some on- and off-time on the method, often changing the algorithm entirely. The steady-state compensation scheme is inspired by earlier work I did on statistical representation for landscapes while applying physically-based laws. The fast sweeping algorithm which is used for DEM correction and flow accumulation was another milestone. I had known about the algorithm for a while through an enthusiastic artistic coding community (shadertoy.com). However, I had never encountered the realization that DEM correction and flow accumulation through networks would benefit from this (as well as the geo-spatial spread algorithm). Finally, it nearly reached its current form. A small nudge from my wife and colleagues later, and the FastFlood website was born.

Licence

The client-side JavaScript of this website, with the exception of the model kernel code, and any back-end infrastructure and code, is published under the GNU General Public Licence version 3. Please find a full version of this licence here: https://www.gnu.org/licenses/gpl-3.0.en.html. Some of the core algorithms are part of the LISEM model repository on Github, also GPL3 licensed. This licence allows for free use and adaptation for non-commercial usage of the software. When distributing altered code, credit must be given to the original authors, and this licence, or a compatible licence, must be maintained. If the GNU-GPL3 licence does not work for your use-case, please contact one of the authors to explore other options.

While the model method itself is published, the model code remains closed-source for now. If we ever decide to stop with the www.fastflood.org tool, I aim to publish the source code under the GPL licence as well.

Acknowledgements

Special thanks are given to all of the contributors to the code, and those that have otherwise helped with development (Thank you Lois, Giacomo, and Luigi). Additionally, this work would not have been possible without the amazing efforts for free open software within the field of Geoscience and beyond.