Throughout the world, there is a growing need for integral water solutions. We need protection from excess water in order to live safely in delta areas and river basins. Our water systems also need to be clean and sustainable. To support water authorities, consultancy firms, research institutes and universities worldwide, Deltares offers an integrated 1D/2D modelling suite called SOBEK for integral water solutions.

SOBEK is a powerful modelling suite for flood forecasting, optimization of drainage systems, control of irrigation systems, sewer overflow design, river morphology, salt intrusion and surface water quality. The modules within the SOBEK modelling suite simulate the complex flows and the water related processes in almost any system. The modules represent phenomena and physical processes in an accurate way in one-dimensional (1D) network systems and on two-dimensional (2D) horizontal grids. It is the ideal tool for guiding the designer in making optimum use of resources.

Delft3D Flexible Mesh (Delft3D FM) with 1D network functionality for river modelling, the successor of SOBEK

Fields of application

SOBEK is a modelling suite designed for water authorities and water management consultancies. Is is suited for modelling and analysis of:

  • Irrigation and drainage systems / rural systems: open channel hydraulics
  • River systems
  • Sewerage and urban drainage systems (closed conduits, pipe flow)
  • Inundation and flooding scenario simulations
  • Water quality predictions
  • and the design and optimization of control systems for canal and waterway automation


SOBEK has been developed jointly with Dutch public institutes and governmental organisations, research institutes, universities and private consultants all over the world.

Integrated approach
SOBEK offers one software environment for the simulation of all management problems in the areas of river and estuarine systems, drainage and irrigation systems and waste water and storm water systems. This allows for combinations of flow in closed conduits, open channels, rivers overland flows, as well as a variety of hydraulic, hydrological and environmental processes.

Powerful simulation engine
The hydrodynamic 1D/2D simulation engine is the computational core of SOBEK. This engine allows the combined simulation of pipe, river-, channel- and overland flow through an implicit coupling of 1D and 2D flow equations. SOBEK is the ideal tool for studying the effects of dam breaks, river floods, dike breaches, urban flooding etc.

Robust numerical operations
The hydrodynamic 1D/2D simulation engine is equipped with a very robust scheme for numerical computation. It also guarantees mass conservation, even in case of transitions through suddenly varying cross section shapes. The engine combines computations of subcritical and supercritical flow, at scales selected by the user. It handles flooding and drying of channels without the use of artificial methods such as the Preissmann slot.

Numerical efficiency
The hydrodynamic 1D/2D simulation engine has a very efficient numerical solution algorithm. The algorithm is based upon the optimum combination of a minimum connection search direct solver and the conjugate gradient method. It also applies a variable time step selector, which suppresses the waste of computational time wherever this is feasible.

Size of models
The size of the model is only limited by the size of the internal memory of the computer used.


How to get SOBEK?

The latest fully validated SOBEK Suite is version 2.14.001. This version is available via our SOBEK Service Packages. You can easily order these products via and then download the software via our Download portal.



SOBEK Suite versus Delft3D Flexible Mesh Suite

Within our Next Generation Hydro Software (NGHS) project, Deltares is working on the integration and improvement of its hydro software. Important technological innovations make up the new Delft3D Flexible Mesh Suite (Delft3D FM) for integral simulations. Delft3D FM combines proven technology from the hydrodynamic engines of Delft3D 4 and SOBEK 2 and adds flexible administration and in near future unique subgrid methods. The new, advanced software will allow water managers and modelers to do their work better and faster.

Delft3D FM will be the aggregated successor of SOBEK-Rural and DUFLOW for irrigation and drainage systems, SOBEK-RE and SOBEK-River for river systems, and SOBEK-Urban for sewerage and urban drainage systems. Delft3D FM is set up within the Delta Shell Framework, providing additional functionality, extensive compatibility and an intuitive user interface. The current performance (simulation time) of the prototypes of Delft3D FM with 1D-2D functionality, also called SOBEK 3, is comparable to the performance of DUFLOW and SOBEK-RE. SOBEK 3 prototypes are available for all SOBEK 2 users. Check the support tab for migrating SOBEK 2 to SOBEK 3 prototype.

Delft3D FM is open source software. We aim at actively promoting Delft3D FM in open source late 2016.

As long as not all functionality of SOBEK 2 is available in the new Delft3D FM, we will provide SOBEK 2 as part of our SOBEK Service Packages.

Delft3D FM Key Features

The most prominent features of Delft3D FM:

  • Central map with spatial editor
  • Customizable and dockable window views
  • Connectivity to online data bases
  • Python scripting
  • Delft-FEWS, OpenDA and OpenMI compatibility
  • Delta Shell Framework
3D interactive urban flood modelling using Delft3D Flexible Mesh (Delft3D FM) on a Touch Table

3D interactive urban flood modelling using Delft3D Flexible Mesh (Delft3D FM) on a Touch Table



The validation of a modelling system such as SOBEK and Delft3D FM requires continuous attention. Even though the individual modules of the suite have been thoroughly tested during their development, the suite as a whole requires intensive testing and validation too. To this end, a regular programme is established and tests of many of the most likely combinations are continually performed. As a policy, new versions are released only after an extensive beta testing period, to ensure that our users are only provided with stable and validated products.