Delft3D FM

Short Name: Short name of model
Delft3D FM
Long Name: Long name of model
Delft3D FM Suite 1D2D
Model Type: Event or continuous in time; distributed, semi-distributed, or lumped in space
1D, 2D, 1D/2D.
Usage: Demonstrated application purposes with emphasis on flash flood and riverine flood forecasting; include wildfire/debris use-cases where applicable
The product line 1D2D supports the following usage:
  • Flood forecasting (1D2D), optimisation of drainage systems, control of irrigation systems, sewer overflow design.
  • Riverine discharge flow and height stage (water surface elevation)
  • Flood extent and 2D flow paths
  • Flood hazard mapping (velocity and depth)
  • Design flood modelling – planning and design of levees and flood mitigation structures
  • Dam and Levee breach analysis
  • Mixed flow regimes
  • Simulation of Rainfall Runoff processes
  • Simulation of Real Time Control of Hydraulic Structures
  • Coastal Hazard modelling, without waves

The following modules are included in the Delft3D FM Suite 1D2D:
  • D-Flow FM: 1D, 2D and 1D2D hydrodynamics
  • D-Real Time Control: FeedBackControl on 1D and 2D hydrodynamic structures
  • D-Rainfall Runoff: Lumped Rainfall Runoff modelling

For coastal hazard modelling, including waves, sediment transport, morphology and water quality, we currently recommend to use the Delft3D FM Suite 2D3D. This is the 2D3D productline of the Delft3D FM Suite.
Background: Description of model history and background
Delft3D FM Suite 1D2D is the successor of the SOBEK Suite. The first version of SOBEK was released in 1993. Since that time there have been several major releases of this software package. Currently 38.000+ users and developers are active in the Delft3D open source community: https://oss.deltares.nl/web/delft3dfm

Delft3D is Open Source Software (OSS) since January 2011.
Grid Shape: Shape of grid used (rectangular, curvilinear/structured and triangular/unstructured, flexible mesh)
Flexible Mesh: Unstructured meshes, irregular grids, such as triangles, quads, pentagons, hexagons. And also structured/regular grids, such curvilinear and rectilinear grids.

The hydrodynamic module of the Delft3D FM Suite is D-Flow Flexible Mesh (D-Flow FM) module. This module is the successor of the structured SOBEK-FLOW module and the structured Delft3D-FLOW module. D-Flow FM is capable of handling curvilinear grids that provide very good performance in terms of computational speed and accuracy. In addition to this, the grid may also consist of triangles, quads, pentagons and hexagons. This provides optimal modelling flexibility and ease in setting up new model grids or modifying existing ones, or locally increasing resolution.

We recommend to use orthogonal curvilinear grids in majority of domain. This offers a very accurate solution aligning with channels, gullies and coast lines. You may couple and refine those grids by triangles, pentagons. This offers best of both worlds.

1D- and 2D grids can be combined. 1D2D options available are:

  • Longitudinal
  • Lateral
  • Embedded
  • Vertically stacked (sewer systems)

Both Cartesian and spherical coordinate systems are supported. This facilitates tidal computations on the globe with tide generating forces, thus without imposing open boundary conditions.

For more information, see https://www.deltares.nl/en/software/module/d-flow-flexible-mesh/, the D-Flow FM User Manual and the D-Flow FM Technical Reference Manual.
Grid Type: Discretization of the modeling domain
D-Flow FM implements a finite volume solver on a staggered unstructured grid. For more information, see the D-Flow FM Technical Reference Manual.
Model Assumptions: Model assumptions are simplifying statements, choices or conventions on which the model is based (2D Shallow Water Equations (St Vennant), Diffusive wave or kinematic wave, Sub-grid losses (eddy viscosity))
The D-Flow FM module of the Delft3D FM Suite 1D2D works with the complete Saint Venant Equations, including transient flow phenomena and backwater profiles. For 1D networks, it models any cross section (open and closed), including asymmetrical profiles, and y-z profiles. It even allows you to define different subsections within a cross section, using alternative resistance formulations and/or coefficients in each subsection.

The higher-order advection treatment and near-momentum conservation make the solver very suitable for supercritical flows, bores and dam breaks. The handling of wetting-and-drying makes it suitable for flooding computations. The continuity equation is solved implicitly for all points in a single combined system. Optionally, non-linear iteration can be applied for very accurate flooding results. Furthermore, Coriolis forcing, horizontal eddy viscosity, tide generating forces and meteorological forcings were added, making the system suitable for tidal, estuarine or river computations.
Input Data: What types of input data are required for the model
  • DEM, topography, hydraulic structures, surface characteristics/roughness
  • Ability to model 1D elements of hydraulic structures(bridge or culvert)
  • Gridded rainfall
  • Inflow boundary conditions (tide, upstream flows)
  • Dambreak / releases
Input Format: What file formats can be used for input data
Delft3D FM Suite 1D2D: project file *.dsproj, *.mdu (reference to raster files, external forcing files, model parameters); *_net.nc (1D, 2D and 1D2D network file), crsloc.ini (cross section locations, including id, branch id, chainage, vertical shift), crsdef.ini (cross section definition file, including xyz, yz, zw, rectangle, circle), Roughness-*.ini, initialFields.ini, Structures.ini (hydraulic structures, including weir, universal weir, culvert, bridge, pump, orifice, gate, general structure, dambreak, compound structure), *_bnd.ext (external forcing files, such as boundary conditions, laterals, meteo), *.bc (boundary conditions), *_fwx.pliz (fixed weirs), *_obs.pl (observation points), *_crs.pli (observation cross sections)

ASCII, NetCDF, GIS Format, CSV Format.
Input Time Interval: What time interval is required for input data, and how are daily values utilized
Options range from 1 minute to daily, with automatic linear interpolation to the simulation time interval.
Optimization or Calibration: What tools are available for calibration and optimization
Manning’s n Values tables; Flow vs Roughness factors; Graphical plots with observed data (profile, cross section, hydrograph plots).
Data Assimilation: Can observed flow and previous forecast flow be used to update the forecast flow
Yes, using OpenDA toolbox in combination with the Delft3D FM modules. For more information, see https://docs.openda.org/en/latest/
Ensemble: Can ensemble meteorologic forecasts be used in the model
Yes, by using the combination of the Delft-FEWS Platform, the OpenDA Toolbox and the Delft3D FM Suite.
Uncertainty: How is uncertainty represented in the outputs
Yes, physical parameter sensitivity analysis by using the combination of the Delft3D FM modules and the Probabilistic Toolkit (PTK).
Simulation Time Interval: What time interval is used for simulation
Range of time intervals used, uniform and variable time steps available for the 1D and 2D unsteady flow modelling.
Model Output Time-Series: What time-series outputs are available
NetCDF:
  • *_his.nc (time series)
  • *_map.nc (spacial distributed 1D and 2D output data, such as velocity, depth, flow)
  • *_clm.nc (similar to map file, but the output in classes)
  • *_fou.nc (Fourier output, including max and min values)
  • *_yyyymmdd_HHMMSS_rst.nc

ASCII:
  • *.dia (diagnostics)
Time-Series Format: What is the file format for output time-series data
NetCDF Ugrid
Model Output Statistics: What types of output statistics are available
Mean, standard deviation, minimum and maximum
Statistics Format: What is the file format for output statistics data
NetCDF
Inventory Platform: Platforms from this inventory in which this model can be integrated
Delft-FEWS Platform
Additional Platform: Additional platforms outside this inventory in which this model can be integrated
–
Installation: Difficulty level for installation and configuration
Automatic installation package.
User Education: Education level recommended for users
BSc
Degree of Difficulty: Score from 1 (difficult) to 5 (easy) rating the overall difficulty of use
3
GIS Support: How much GIS support is included for watershed delineation and parameter estimation
QGIS hydrology tools
Data Preparation: What tools are included for importing and preparing time-series data
Delft3D FM Suite 1D2D
Model Parameters: Parameters used in model calibration
Roughness (e. Chézy, Manning, White-ColeBrook or Z0) , time step and mesh size, numerical coefficients (turbulent mixing coefficients, weir coefficient)
Parameter Estimation: What tools are included for estimating model parameters from physical data
OpenDA Toolbox. OpenDA is a generic environment for data assimilation tasks like parameter calibration and measurement filtering. It provides a platform that allows an easy interchange of algorithms and models.
Model Calibration: What tools are included for model calibration
OpenDA Toolbox, including optimization algorithms, such as Dud, Sparse Dud, Simplex, Powell, Gridded Full Search, GLUE, SCE, Conjugate gradient, LBFGS.
Model Verification: What tools are included for model verification
Same as above.
Model setup interface: Does the model use GIS to create setup files or does it have an integrated mapping GUI and point and click setup
Integrated mapping and visualization GUI can be used for model setup.
Visualization of model output: Does the model use separate GIS to visualize output files or does it have an integrated mapping and visualization GUI
Standard: Integrated mapping and visualization GUI. Additional tools:
Hardware Requirements: Can the model run on as:
  • PC
  • Virtual server environment
  • Supercomputer
  • Standard option: PC
  • For running on supercomputers, we recommend to use our Apptainer option
  • For running in the cloud / virtual server environment, we recommend to use our Docker container option.
Operating System: Operating system – MS Windows, LINUX
Microsoft Windows 10 (64-bit) and Microsoft Windows 11 (64-bit)

LINUX: Alma Linux 8, computational core only
Language of Core Code: Programming language used for the core code (e.g. Fortran, C++, Java). If workflow scripting is supported (e.g. Python) then please specify
For the computational cores, Fortran is used. Most of the Graphical User Interface components are developed using the C# programming language.
Open Source: Open source or closed source
Yes, the Delft3D source code is available free of charge via https://github.com/Deltares/Delft3D under GNU AGPLv3 conditions.

The pre-compiled fully validated distribution (setup, manuals and tutorials) is available via several services packages to suite specific needs. The 2026 Basic Service Package is available for 4,316 euro, excluding VAT. The distribution is unlimited in the number of users. For more information, please visit https://www.deltares.nl/en/software/delft3d-flexible-mesh-suite/#service-packages
Last Update and Version: Date of latest update and the version number for the release
24 October 2025: 2026.01
Next Update and Version: Date of next planned update and the version number for the release
Q2 2026: 2026.02
Active Development Community: Is there an active developer community with regular updates and new releases?
Platform Integration: Platforms in the inventory which integrate this model
–
Download URL: URL that can be used to download the software
Free to Download and Use: Is the software free to download and use?
Yes, the Delft3D source code is available free of charge https://github.com/Deltares/Delft3D under GNU AGPLv3 conditions.
Language of Software Interface: Languages used for the software user interface
English
Online Support URL: URL that can be used to get online support
Training Material URL (including example data sets): URL that can be used to access training material
Language of Trainings: Languages used for the training material
English
Guidance Material URL (including case studies and benchmarking of performance/speed): URL for case studies and examples of its use. Ideally including benchmarking of performance
Language of Guidance: Languages used for the guidance material
English
References: Reference from scientific journals or publications
For an overview of Delft3D FM publications, including Nature publications, please visit: https://oss.deltares.nl/en/web/delft3dfm/research

For 16.000+ Delft3D and related publications, please visit: https://scholar.google.nl/scholar?hl=nl&q=delft3d&btnG=&lr=
Owner: Contact organization for the software. Could be core developer
Deltares: https://www.deltares.nl/en/

Software team: software@deltares.nl , +31 (0)88 335 8188

General address Deltares: P.O. Box 177, 2600 MH Delft, The Netherlands, tel: +31 (0)88 335 8273 (08:00 and 17:30 hours)
Developer: Contact of the organization that created and built the software
See Owner
 

Download hydrologic model template