Overview

About this manual

This document is the User Manual for the TUFLOW Classic and TUFLOW HPC hydrodynamic computational engines.

From the 2025.0.0 TUFLOW release onwards, new features, improvements and changes between releases are provided centrally in the TUFLOW Classic/HPC Changelog. Documentation for all previous releases, including archived manuals, is available from TUFLOW Downloads Archive. A summary of default changes between releases since 2006 is provided in 18  Default Changes.

How to use this Manual

This section provides an overview of the manual structure and the navigation features available to help locate information. These instructions are only provided in this section.

Searching

The search function (top of the left sidebar) searches the entire manual, including chapters, tables, appendices and references. Matching results are displayed with a short preview of the surrounding text to help identify the relevant result before navigating to it.

Cross-references are used throughout the manual to link related content, including sections, figures, tables, equations, commands, etc. Hovering over a cross-reference displays a preview of the linked content. Selecting the link navigates directly to the referenced item.

The References chapter contains a complete list of all publications and resources cited throughout the manual.

Tables

Where appropriate, tables are searchable via the use of the search box, which is located at the top right of any search enabled table. Not all tables are searchable. When text is entered into the search box, table rows are dynamically filtered to only show those that contain the search text. This allows on-the-fly condensing of large tables so that only relevant content is presented.

Tables can be sorted alphabetically (or reverse alphabetically) with respect to any column by clicking (and re-clicking) the column headers. By default, all rows are displayed, however; the number of rows displayed is selectable via the ‘Show entries’ drop down. Undisplayed rows can be accessed by clicking Previous or Next or by using the numbered navigation boxes, all of which are located at the bottom of each searchable table.

Interactive Figures

Some figures are interactive, allowing data to be explored directly within the manual. Depending on the figure, this may include inspecting individual data points, zooming and panning, or using sliders to view changes in data over time.

Note

In the PDF version of the manual, interactive figures are displayed as static images.

Commands

Commands are displayed in highlighted text and are often provided as a clickable link to their corresponding command description in their command appendix. For TUFLOW Classic/HPC, there is a separate command appendix for each control file. For example, Appendix A — TCF Commands, Appendix B — ECF Commands, etc.

The command appendices provide detailed descriptions of each command and its inputs. Each command includes a summary block containing key information such as status, solver, etc. Command inputs are then described either within individual sections or in tabulated form, depending on the complexity. The table of contents in the right sidebar provides a convenient way to browse commands and inputs within the appendices.

TUFLOW commands use a structured, colour-coded syntax that is consistent throughout the documentation.

Colour coding:

  • Blue: The command
  • Red: The operator (==)
  • Black: The input(s)/parameter(s)
  • Green: Comments (must be preceded by !)

A vertical bar (|) separates the different input options for a command. Default values are enclosed in curly brackets ({}) and user defined values are enclosed in angled brackets (<>).

For example, the following command has the default input h V or allows user defined <data_types>:

Map Output Data Types == {h V} | <data_types>   ! command definition

Map Output Data Types == h V                    ! default command inputs - used if the command is not specified

Map Output Data Types == h V d dt               ! example user defined input

Example command blocks are typically provided within scrollable code blocks. These blocks can be copied directly into a text editor when building a model control file. Select the icon in the upper right corner of the block to copy the entire command block to the clipboard. An example block is provided below:

Geometry Control File == ..\model\example_001.tgc   ! Reference the TUFLOW Geometry Control File
BC Control File == ..\model\example_001.tbc         ! Reference the TUFLOW Boundary Control File
BC Database == ..\bc_dbase\bc_dbase.csv             ! Reference the Boundary Conditions Database
Read Materials File == ..\model\materials.csv       ! Reference the Materials Definition File

Glossary and Notation

Table 1: Glossary of Terms
Term Description

_messages

ERROR, WARNING, CHECK and other useful messages that are output to the Console Window and log file are also output to GIS file provided the message can be geographically located within the model domains. The messages and other information are written to a file called _messages which is located in the same folder as the .tcf file or in the “Log” folder.

_run_stats.txt

This file contains a summary of the amount of time that TUFLOW spends in the 1D and 2D computations.

_start_stats.txt

This file contains information summarising the total time and the time elapsed for each stage of model initialisation. This can be used to identify the stages causing slow simulation start-up.

ADI

Alternating Direction Implicit. The TUFLOW Classic solver is a 2D ADI 2nd order spatial finite difference CPU solver.

Advection-Dispersion

A process in fluid dynamics that describes the movement (advection) and spread (dispersion) of substances (such as pollutants, nutrients, or sediments) in a fluid (usually water or air).

ArcGIS Pro Toolbar

The ArcGIS Pro Toolbar, helps with streamlining the process of creating and editing a TUFLOW model in the GIS software ArcGIS Pro.

ArcMap Toolbox

The toolbox helps with streamlining the process of creating and editing a TUFLOW model in the GIS software ArcMap.

ArcMap/ArcGIS

ArcMap and ArcGIS Pro are distributed by ESRI https://www.esri.com/. They are GIS software packages that can be used to develop the georeferenced input data for TUFLOW. TUFLOW writes result and check files which are compatible with ArcMap and ArcGIS Pro also.

attribute

Data associated with/or attached to a GIS object. For example, an elevation is attached to a point using a column of data named Height”. The “Height” of the point is an attribute of the point.”

Build

The TUFLOW Build number is in the format of year.minor.patch convention. The year corresponds to the major version number. Throughout the year, additional minor releases (releases containing new features and bug fixes, but no breaking changes) would increment the minor version number and bug fix only releases would increment the patch version number. The Build number is written to the first line in the .tlf log file so that it is clear what version of the software was used to simulate the model. A example build number is: 2025.0.0.

cell

Square shaped computational element in a 2D domain.

centroid

The centre of a region or polygon.

channel

Flow/velocity computational point in a 1D model. Channels convey the water through 1D domains. They vary in characteristics from open channels to a wide range of structures and conduits.

Classic

TUFLOW’s “Classic” solver is a 2D ADI (Alternating Direction Implicit) 2nd order spatial finite difference CPU (Central Processing Unit) solver. TUFLOW Classic was the original TUFLOW 2D solver, which started development in 1989.

CnM

CnM is a Chezy C, Manning’s n or Manning’s M bed resistance value.

code

Code refers to the value assigned to cells to indicate a cell’s active or inactive status.

command

Instruction syntax in a TUFLOW control file.

control file

Text file containing a series of commands (instructions) that control how a TUFLOW simulation domain is built and how a simulation shall execute.

CPU

Central Processing Unit. TUFLOW can run on either CPU or GPU hardware.

DEM

Digital Elevation Model. Interchangeable with DTM.

Double Precision (DP)

Double precision numbers use 8 bytes.

DTM

Digital Terrain Model. Interchangeable with DEM.

element

A discrete feature in a 1D domain model, for example, a node or channel. For TUFLOW Classic and HPC, “element” refers to a square shaped computational element in a 2D domain, and is interchangeable with “cell”.

ESTRY

ESTRY is original name given to the primary 1D solver built into TUFLOW. The terms ESTRY and TUFLOW 1D may be used interchangeably throughout this Manual.

fixed field

Lines of text in a text file that are formatted to strict rules regarding which columns values are entered into. This format was used for old versions of ESTRY and TUFLOW, and is no longer supported. If using an older version of TUFLOW, which uses this format, please refer to previous manuals for the full documentation.

flushing assessment

An evaluation process used to assess the effectiveness of water movement (flushing) in a water body (such as a river, lake, or reservoir). It determines how well the water body can remove or dilute pollutants, sediments, or nutrients.

fluvial flooding

Fluvial flooding refers to riverine flooding (excessive rainfall causing a river to exceed its capacity).

Fric

The field used to store bed friction information. This may be the material type or ripple height.

GIS

Geographic Information System. For use in TUFLOW modelling it will need to be able to import/export files in supported formats as documented in this manual. Common GIS Software used for TUFLOW modelling includes ArcMap, ArcGIS Pro, QGIS or MapInfo.

GPU

Graphics Processor Unit. TUFLOW HPC has been specifically designed for compute using NVIDIA architecture Graphics Processor Unit (GPU) hardware. HPC is the premier and recommended 2D TUFLOW fixed grid solver.

Grid

The mesh of square cells that make up a TUFLOW Classic or HPC model.

HPC

TUFLOW’s “HPC” (Heavily Parallelised Compute) solver is a 2D explicit, 1st or 2nd order spatial and 4th order temporal, parallelised finite volume solver. TUFLOW HPC has been specifically designed for compute using NVIDIA architecture Graphics Processor Unit (GPU) hardware. HPC is the premier and recommended 2D TUFLOW fixed grid solver.

hydraulic jump

A phenomenon in fluid dynamics where there is a sudden transition from supercritical to subcritical flow. This abrupt change in flow conditions results in a significant rise in the water surface. It is commonly seen below weirs and sluice gates where a smooth stream of water suddenly rises at a foaming front.

Integrated Urban Drainage

An approach to planning or managing an urban drainage system. Integrated Urban Drainage (IUD) takes into account all aspects of an urban drainage system that contribute to water quality and flooding problems.

invert

The elevation of the base (bottom) of a culvert, structure or channel.

IWL

Initial Water Level.

land cell

A land cell is one that will never wet (i.e. an inactive cell).

layer

A GIS data layer containing the shapes of the geographically located objects and the attribute data associated with each object.

LIDs

Low-impact developments (LIDs) features for modelling green infrastructure.

line

A GIS object defining a straight line defined by two points. See also, polyline (Pline). Throughout this document, ‘lines’ refer to both lines (2 vertices) and polylines (more than 2 vertices).

M2D

The Multiple 2D Domain (M2D) module is an add on module for the TUFLOW Classic Solver. It allows for a number of 2D domains of different cell sizes and orientations to exist within a single model.

Manning’s n

A coefficient which represents the roughness or friction applied to the flow by the channel. For example, a closed finished concrete conduit flowing partly full has a Manning’s n of 0.012.

MapInfo

MapInfo is distributed by Precisely https://www.precisely.com/product/precisely-mapinfo/mapinfo-pro. MapInfo is a GIS software package that can be used to develop the georeferenced input data for TUFLOW. TUFLOW can also write result and check files, which are compatible with MapInfo.

Mat

An integer defining the Material (land-use) type in a look-up table.

material

Term used to describe a bed resistance category or land-use. Examples of different materials are: river, river bank, mangroves, roads, grazing land, sugar cane, parks, etc.

miTools

MapInfo and TUFLOW Productivity Utilities (miTools) were developed to improve the efficiency of setting up and reviewing TUFLOW models, as well as improving the day to day ease of using MapInfo Professional.

Morphology

A particular form, shape, or structure. For example, coastal morphology typically refers to the movable sand bedform shape of the coastal system.

Nc

Wave Celerity Number.

Nd

Diffusion Number.

node

One of: - A junction/end of one or more channels where the water level (if an open channel is connected) or pressure head (e.g. closed pipe junction) is computed in a 1D domain. - Node in a model mesh used for viewing 2D results in SMS. The nodes are located at the cell corners. - Node is also used by MapInfo to refer to vertices along a line or a region (polygon).

Non-Newtonian Flow

Non-Newtonian Flow refers to the flow of fluids that do not follow Newton’s law of viscosity. An example of Non-Newtonian flow is flows originating from a failed slurry mine tailings dam.

Notepad++

Notepad++ is a free text editor available from https://notepad-plus-plus.org/downloads/. The Notepad++ functionality listed below makes it well suited as an editor for creating and updating TUFLOW control files.

Nu

Courant Number.

null cell

A null cell is an inactive 2D cell used for defining the inactive side of an external boundary.

obvert

The elevation of the underside (soffit) of a culvert or other structure.

Override File

Override Files allow the user to apply .tcf commands after TUFLOW has finished processing the commands which are referenced within the .tcf file.

Particle Tracking

The TUFLOW Particle Tracking Module (PTM) enables the 2D or 3D simulation of discrete Lagrangian particles as they are transported by a flow field and/or other forcing terms (e.g. wind drift).

peer to peer access

Some models of NVidia GPUs allow for a direct communications link between them, either via a specific hardware connector or via the PCI bus controller. This is known as ‘peer to peer’ access.

pit

A point object with attributes that are used to define a pit channel for modelling flow into urban stormwater inlets/gully traps/drains/pits, then into a manhole.

pit channel

A small channel inserted at a pit, typically used to convey water from overland 2D domains to 1D pipe networks.

pit inlet

The entrance to a pit channel (e.g. a gully trap).

pluvial flooding

Pluvial flooding refers to surface water flooding that is driven by local rainfall excess and is unrelated to river rising.

point

GIS object representing a point on the earth’s surface. A point has no length or area.

polygon

See region.

polyline (or Pline)

A GIS object representing one or more lines connected together. A polyline has a length but no area. Throughout this document, ‘lines’ refer to both lines (2 vertices) and polylines (more than 2 vertices).

polyline segment

One of the straight line (2 vertices) segments that make up a polyline (more than 2 vertices).

PyTUFLOW

PyTUFLOW is a package of Python tools for extracting TUFLOW time series results. It can be used to automate output tasks such as checking model health, goodness-of-fit for model calibration, viewing on-the-fly model output (used in conjunction with Write PO Online == ON), and high-volume output plotting from production runs.

QGIS

QGIS is free open source software https://qgis.org/ that can be used to develop the georeferenced input data for TUFLOW models, and view results via the TUFLOW Viewer Plugin also available for free. TUFLOW writes result and check files that are compatible with QGIS.

QGIS TUFLOW Plugin

The QGIS TUFLOW Plugin provides a range of pre- and post- processing tools, and dynamic viewing of 1D and 2D results in TUFLOW Viewer.

Quadtree

A feature of the TUFLOW HPC 2D solver that allows the use of a quadtree mesh (dividing one 2D cell into four cells).

radial gate

A radial gate (also called tainter gate) is a type of floodgate used to control water flow.

raster

Gridded GIS raster data layers: GeoTIFF (.tif), GeoPackage (.gpkg), Float (.flt) and ASCII (.asc) formats.

Read File

A file that is included inside another file using the Read File command in .tcf, .tgc and .ecf files. Minimises repetitive specification of commands common to a group of files.

region

A GIS object representing an enclosed area (i.e. a polygon). A region has a centroid, perimeter and area. Regions or polygons can have internal holes.

SGS

Sub-Grid Sampling. A feature built into the HPC 2D solver that more accurately defines a 2D cell’s geometry using the (finer) resolution of the underlying terrain/bathymetric data. Using SGS can considerably improve the accuracy of the 2D modelling.

Single Precision (SP)

Single precision numbers use 4 bytes.

sluice gate

A moveable gate that can be raised to allow water to flow under it. When a sluice gate is lowered, it can act as a weir as water may spill over the top.

snap

When geographic objects are connected exactly at a point or vertex of a line or region. ArcMap, ArcGIS Pro, QGIS and MapInfo all have a “snap” feature, which ensures the features have the same coordinates. The snap tolerance can be changed in TUFLOW using the Snap Tolerance command.

soffit

The elevation of the underside of a bridge deck or the inner top of a culvert. Same as obvert. Note this manual uses the term obvert.

stage-discharge curve

A curve (graph) that shows the relationship between the water level (stage) in a body of water (e.g. river) and the corresponding flow rate (discharge) at that stage.

subcritical flow

A flow condition or behaviour where the fluid velocity is slower then the wave velocity.

Sub-grid-scale turbulence

Horizontal turbulent diffusion of momentum or eddy viscosity.

supercritical flow

A flow condition or behaviour where the fluid velocity is higher than the wave velocity.

SWMM

EPA Storm Water Management Model (SWMM).

TIN

Triangulated Irregular Network.

TUFLOW 1D

See ESTRY.

vertex

Digitised point on a line or region (polygon).

vertices

Plural of vertex.

VS Code

Visual Studio Code (commonly referred to as VS Code) is a free source code editor developed by Microsoft. It supports a variety of file types and can be used to work with TUFLOW control files. Thousands of free plugins exist for VS Code and some of them are useful when working with TUFLOW models.

XF

XF files are a binary echo of selected input files automatically created by TUFLOW to vastly speed up the model initialisation process next time a simulation is carried out.

ZC

The “ZC” point is located at cell centers. This is a computational point where the mass balance equation is calculated. located in the centre of a 2D cell. The model elevation is also sampled here.

ZH

The “ZH” point is located at cell corners. This point plays no role computationally but is used as an elevation point and for some output formats.

Zpt or Zpts

Points where ground/bathymetry elevations are defined. These are located at the cell centres, mid-sides and corners.

ZU

The “ZU” point is located midway along the right hand face of the 2D cell. This is a computational point, where the velocity in the X-direction is calculated. The cell’s left hand face also has a u-point belonging to the neighbouring cell to the left. The model elevation is also sampled here.

ZV

The “ZV” point is located midway along the top face of the 2D cell. This is a computational point, where the velocity in the Y-direction is calculated. The cell’s bottom face also has a v-point belonging to the neighbouring cell to the bottom. The model elevation is also sampled here.