Version 4.2.0

This major release introduces several new features, model enhancements, and performance improvements. Key highlights include the new LAGRANGIAN module in BASEHPC for simulating the transport of particulate substances using particle tracking as an alternative to traditional Eulerian tracer transport, the new MASSMOVEMENT module for simulating tsunamis generated by subaqueous landslides, new hydraulic boundary conditions for wave generation, new internal bedload boundary conditions, and optimized nodestring state handling to reduce memory and computation time in hydrodynamic simulations with nodestrings in BASEHPC.

The suspended sediment transport model of BASEMD has been improved to ensure better mass conservation, and the mesh-related workflow between the 2D models of BASEHPC and BASEMD has been unified.

This release also adds ARM64 Windows support, updates Linux compatibility to Ubuntu 24, and includes multiple bug fixes and refinements for improved stability and performance. See the detailed list of changes below.

General

• Added an installer specifically compiled for Microsoft Windows 10 and 11 on ARM64-based systems. This version allows BASEMENT to run natively on ARM64 Windows devices and supports use on Apple Silicon–based Macs (M-series) through virtualized Windows ARM environments such as Parallels Desktop for Mac.
  Note: GPU acceleration (CUDA) is not supported on ARM-based systems.

• Added support for Ubuntu 24; support for Ubuntu 18 has been dropped.
  

Bug fix

• The console output format in the GUI has been improved.

Known Issues

• Model setup fails if there is a dot ‘.’ in the working directory path. For example: “MySimulations/Sim1.1/" does not work, while “MySimulations/Sim1_1/” works.
• Aborting a simulation using Ctrl+C can corrupt the HDF5 result file.
• Abort bottom may no work as intended, i.e. simulation does not stop.
• Existing installations of BASEMENT version 3.0.1 (or earlier) are not automatically detected by the updated installer. Therefore, uninstall any previous version of BASEMENT e.g. using the link in the Start Menu before installing the newest version.

Module BASEHPC

General

• Introduced the new LAGRANGIAN transport module in BASEHPC, providing an alternative to traditional Eulerian tracer transport for simulating the movement of particulate substances in riverine environments. This module tracks discrete particles advected by the flow field derived from the Hydrodynamics module, enabling mesh-independent and low-diffusion transport modeling. Typical applications include modeling of pollutant dispersion, larval drift, seed transport, and microplastic pathways in rivers. Key features include:
  • Particle advection governed by the local 2D velocity field, with optional turbulent diffusion modeled via a stochastic random walk formulation.
  • Support for inertial particles accounting for drag, buoyancy, gravity, and uplift forces.
  • Injection through inflow boundary conditions allowing constant or time-varying particle inflow rates.
  • Automatic particle removal at downstream boundaries and wall-type behavior where no inflow is defined

• Introduced the new MASSMOVEMENT module, enabling simulation of tsunamis generated by subaqueous mass movements. This module provides a simplified wave-generation mechanism in which a predefined landslide mass (of given thickness and extent) is instantaneously removed to represent the mass failure.

• Added two new hydraulic boundary conditions in BASEHPC, primarily for wave generation (e.g., from subaerial mass movements):
  • zqhydrograph: Standard inflow boundary condition imposing a specified water-surface elevation and specific discharge.
  •  zqhydrograph_internal: Internal inflow boundary condition imposing a specified water-surface elevation and specific discharge.

• Three internal bedload transport boundaries have been implemented:
  • equilibrium_internal: Allows deposition up to a specified reference elevation. Deposited material exceeding the reference elevation is transported downstream.
  • wall_internal: Defines an impermeable boundary that blocks bedload transport.
  • dynamic_wall_internal: Defines a temporarily impermeable boundary that blocks bedload transport until a specified wall-collapse time.

• A new parameter max_velocity has been introduced to limit unrealistically high flow velocities that may arise from numerical instabilities. Activating this parameter can help increase the allowable simulation time step when spurious velocities occur. However, since it adds computational overhead, it is recommended to enable it only when such instabilities are observed.

• The introduction of the mixed-size sediment transport module in version 4.1.0 increased the number of nodestring state variables from 10 to 30, leading to higher memory consumption even in purely hydrodynamic test cases. To improve performance, the nodestring state variables have now been separated into hydraulic (HydState) and morphodynamic (MorState) components. This change reduces memory usage and computational cost for simulations that do not involve sediment transport. As a result, the nodestring states previously written to RESULTS/NodeStrg/StateVar are now stored under RESULTS/NodeStrg/HydState and RESULTS/NodeStrg/MorState`.
  

Bug fixes

• Fixed an issue where the variable transport_capacity_abs was written incorrectly to the XDMF file when multiple grain-size classes were used. This error made the file unreadable in QGIS.

• Fixed a bug causing an error in the output variable ns_hyd_discharge when no boundary condition was defined.

• Fixed a bug in the Hunziker–Jaeggi bedload transport formula.

• Fixed an bug in the computation of transport capacity and transport rate for grain-size class 2.
  

Module BASEMD

General

• Improved the 1D (BASEchain) suspended sediment transport model and external source handling to ensure proper mass conservation.

• For 2D (BASEplane) BASEMD simulations, node IDs of Stringfefs no longer need to be listed in the model.json file. They must now be included directly in the 2DM mesh file as Nodestrings with the prefix NS, followed by the list of node IDs and a minus sign for the last node.
  
  Example:
  NS 1 20 21 22 -4
  
  This change unifies the mesh-handling workflow between BASEMD and BASEHPC.

• The tecplot output format for BASEMD (2D) has been removed.

Bug fixes

• Fixed multiple bugs in the BASEchain module (BASEMD) related to cross-section area computation, bed control-volume updating, and gravitational transport.

Known Issues - BASEplane

• The upstream and downstream stringdefs of the inner boundary weir must be of the same length, otherwise mass might not be conserved.

Known Issues - BASEchain

• Fixed bed starts eroding if both suspended load and bed load transport are activated if the suspended load is below transport capacity.
• Van Rijn formula does not result in any sediment being transported (1D-model).