Questions about SFINCS for high-resolution compound flooding modelling in Rotterdam

[tberends]

Dear SFINCS team and community,

We are working on a research project focused on the resilience of the city of Rotterdam. In this project, we aim to study the effects of a compound flood event caused by the combination of high sea levels, high river discharges, and intense rainfall. The research primarily focuses on urban resilience rather than on achieving high model accuracy.

A colleague of my at the TU Delft recently discussed the use of SFINCS with some of the experts from Deltares. She does not have a background in flood modelling and asked me to explore whether SFINCS could be a suitable tool for our research. After going through the documentation, SFINCS seems like a promising option, and I would like to ask a few additional questions:

• Is it possible to use a custom DEM, for example the Dutch AHN dataset?
• The study area is approximately 1x10^9 m², and I would like to run simulations at high resolution within the city (e.g., 1x1 m). Is this feasible to run such a simulation, for example using a quad-tree approach?

Unfortunately, I will not be able to attend the Delft-FEWS Software Days in November to learn more in person, so I hope you can provide some insights. Many thanks in advance for your help!

[Leynse]

Hi Thomas, apologies for the late response - something in the notification settings went wrong.

As response to your questions;

• yes, using HydroMT you can easily import your own DEMs in Python. We have done that before using AHN
• probably, often we use our subgrid approach for this so that you can calculate at a bit courser resolution resulting in a fast model, while still using the highest resolution underlying DEM. This could also be combined with additional refining in certain areas using the quadtree approach.

You can also email me in case of further questions!

Regarding the software days, you cannot join the FEWS user day part, or also not the SFINCS parts?
November 13th user day:
https://softwaredays.deltares.nl/-/delft3d-user-days-2025-day-4?redirect=/program

And training November 14th:
https://softwaredays.deltares.nl/-/fast-compound-flood-modelling-with-sfincs-training-2025

[tberends]

Hello Tim,

No problem, and thank you very much for your helpful response! Great to hear that it's possible to import custom DEMs like the AHN using HydroMT, and that the subgrid and quad-tree approaches offer flexibility for high-resolution modelling. That sounds very promising for our case study in Rotterdam.

Ah, you're right, I was referring to the Software Days in general (I’ve attended the Delft-FEWS days a bit too often in the past). Unfortunately, I won’t be able to attend any of the sessions in November as I’ll be on leave during that time.

We plan to start working with SFINCS towards the end of this year or the beginning of next year, and I’ll keep you updated on our findings and experiences with the software. I hope we can also provide some useful feedback based on our use case.