Introduction

How to use this manual

Navigation

This manual is designed for digital use within any web browser and has the following features:

• Section headers, to level five, are directly navigable via the table of contents on the right hand side of the page.
• To navigate between chapters, the sidebar on the left hand side of the page can be used.
• The navigation bar at the top of the screen contains helpful tools:
  • Download pdf version of this manual
  • Toggle dark mode
  • Expand/collapse the sidebar and table of contents
  • Search in the manual
• Model commands, parameters and cross references for tables and figures are navigable through hyperlinks, where appropriate. This includes parameters within equations, which will also appear as blue hyperlinks when active.
• The space bar can be used to scroll down within each page without skipping text. Shift + space bar will similarly scroll up.
• Browser back and forward buttons (or their equivalent keyboard shortcuts alt + left arrow and alt + right arrow, respectively) can be used to navigate through browsing history. Some browsers may not return to the precise scroll location in a page last visited, but to the last clicked section header. Hyperlinks have been built into the body of the manual, and these can be used in lieu of browser buttons if required

It is recommended that this manual be viewed in a browser window that is maximised or operating in full screen mode, with the latter (although browser dependent) typically toggled via the F11 key.

When following hyperlinks, the target (i.e. location on a webpage that is being navigated to) is displayed at the top of the landing page (the page navigated to). The exception to this occurs when a target is located near the bottom of the landing page’s content. In this case, it is not possible for a web browser to display the target at the top of a page because this would generate underlying white space, and as such, the target will appear in the main body (i.e. not at the top) of the landing page.

Searching

This entire manual’s content can be searched by clicking the search icon in the right of the navigation bar (top of the screen). A search bar will open in the centre of the page and the search results will be listed. The search function can also be toggled via the s key. Clicking Cancel will close the search bar.

Tables

Where appropriate, tables are searchable via 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) column headers. Where appropriate, 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 table.

Below is an example of a searchable table. Type “erosion” (with or without the inverted commas) into the search box to see the table behaviour, or change the number of rows displayed and use the navigation buttons at the bottom of the table to look through all the data. The right hand “Links” column sometimes has hyperlinked words that allow navigation between related commands, or different versions of the same command, for ease of access if appropriate.

Colour coding is often used for distinguishing different tabulated data types. In the below example, TUFLOW CATCH commands are in highlighted text and the associated argument options for each command are blue and contained in angled parentheses. Clicking on these arguments will navigate to related content. Colour coding applied to other table types is explained throughout this manual when required.

Table 1: TUFLOW CATCH Commands (Demo)

Command	Description
Deposition Stress ==  \(\langle\;\)\(\tau_{cd}\)\(\;\rangle\)	Used in a material block within a pollutant export model block to set the maximum bed shear stress that allows for deposition to occur. This deposition represents a transfer from a pollutant’s wet to dry store. Deposition will not occur at shear stresses above this value. Applies only to shear stress pollutant export methods. It is not used for accumulation washoff pollutant export models.
Deposition Velocity ==  \(\langle\;\)\(w_s\)\(\;\rangle\)	Used in a material block within a pollutant export model block to set the settling velocity of a pollutant. This settling represents a transfer from a pollutant’s wet to dry store. Settling occurs at all times in the accumulation washoff pollutant export model. Settling only occurs once bed shear stress drops below the user specified value in the shear stress pollutant export model.
Depth Threshold ==  \(\langle\;\)\(d\)\(\;\rangle\)	Used in a material block within a pollutant export model block to set the minimum cell water depth at which pollutant export can occur. Applies to all pollutant export methods.
End Time ==  \(\langle\;\)dd/mm/yyyy hh:mm:ss;\(\;\)hours\(\;\rangle\)	Used in the General commands section of a TUFLOW CATCH control file to set the simulation start date in the format declared by Time Format. It is strongly recommended that ISODATE (dd/mm/yyyy hh:mm:ss) be deployed rather than hours.
Erosion Rate ==  \(\langle\;\)\(E_r\)\(\;\rangle\)	Used in a material block within a pollutant export model block to set the erosion rate of a pollutant. This erosion represents a transfer from a pollutant’s dry to wet store. Erosion only occurs once bed shear stress increases above the user specified value. Erosion will not occur at shear stresses below this value. Applies only to shear stress pollutant export methods. It is not used for accumulation washoff pollutant export models.
Erosion Stress ==  \(\langle\;\)\(\tau_{ce}\)\(\;\rangle\)	Used in a material block within a pollutant export model block to set the minimum bed shear stress that allows for erosion to occur. This erosion represents a transfer from a pollutant’s dry to wet store. Erosion will not occur at shear stresses below this value. Applies only to shear stress pollutant export methods. It is not used for accumulation washoff pollutant export models.
GIS Format ==  \(\langle\;\)SHP;\(\;\)GPKG;\(\;\)MI\(\;\rangle\)	Used in the General commands section of a TUFLOW CATCH control file to set the GIS format of the simulation. This command can be overwritten in the catchment hydraulic model or receiving model blocks if needed.
Hardware ==  \(\langle\;\)GPU;\(\;\)CPU\(\;\rangle\)	Used in the General commands section of a TUFLOW CATCH control file to set the simulation hardware. This command can be overwritten in the catchment hydraulic model or receiving model blocks if needed.
Limit ==  \(\langle\;\)\(L_{acc}\);\(\;\)\(L_{shr}\)\(\;\rangle\)	Used in a material block within a pollutant export model block to set an accumulation (washoff model) or erosion (shear model) limit.
Method ==  \(\langle\;\)Washoff1;\(\;\)Shear1\(\;\rangle\)	Used in a material block within a pollutant export model block to set the pollutant export model.
Rain Threshold ==  \(\langle\;\)\(R_r\)\(\;\rangle\)	Used in a material block within a pollutant export model block to set the minimum rainrate threshold at which a pollutant is released from its dry store. Pollutant export is suppressed below this rate. Applies only to accumulation pollutant export methods. It is not used for erosion pollutant export models.
Rate ==  \(\langle\;\)\(R_a\)\(\;\rangle\)	Used in a material block within a pollutant export model block to set the rate at which a pollutant accumulates to its dry store. Applies only to accumulation pollutant export methods. It is not used for erosion pollutant export models.
SHP Projection ==  \(\langle\;\)rec: ..\..\TUFLOW\model\gis\Projection.prj\(\;\rangle\)	Used in the General commands section of a TUFLOW CATCH control file to set the path to the SHP file containing the TUFLOW CATCH model projection.
Start Time ==  \(\langle\;\)dd/mm/yyyy hh:mm:ss;\(\;\)hours\(\;\rangle\)	Used in the General commands section of a TUFLOW CATCH control file to set the simulation start date in the format declared by Time Format. It is strongly recommended that ISODATE (dd/mm/yyyy hh:mm:ss) be deployed rather than hours.
Time Constant ==  \(\langle\;\)\(T_c\)\(\;\rangle\)	Used in a material block within a pollutant export model block to control the rate at which a pollutant is released from its dry store. Applies only to accumulation pollutant export methods. It is not used for erosion pollutant export models.
Time Format ==  \(\langle\;\)ISODATE;\(\;\)hours\(\;\rangle\)	Used in the General commands section of a TUFLOW CATCH control file to set the simulation date format. It is strongly recommended that ISODATE (dd/mm/yyyy hh:mm:ss) be deployed rather than hours.

Commands

Where specific commands are described, they typically appear in highlighted text. For example:

Catch BC Output Folder ==

If they are a clickable link to the corresponding command description in Appendix A — Commands they will appear as the standard hyperlink coloured text. For example:

Catch BC Output Folder ==

Where commands specify parameters (e.g. erosion rates) then for consistency and brevity, these parameters are included directly in the command example using their notation (see Parameter Notation below) rather than descriptive words. For example:

CSV Write Frequency Day == \(dT_{csv}\)

These notated parameters are also often a clickable link to descriptive explanations in Appendix B — Parameters. For example:

CSV Write Frequency Day == \(dT_{csv}\)

Parameter notation

The primary groups of parameters are listed below, with the letter or symbol used to denote each. Typical generalisations of units are parenthesised.

• Time steps, \(dT\) (seconds or days)
• Rates, \(R\) (mass per unit area per unit time, or rain rate)
• Limits, \(L\) (mass per unit area)
• Concentrations, \(C\) (mass per unit volume)
• Time constants, \(T\) (seconds)
• Water depths, \(d\) (metres)
• Shear, \(\tau\) (Newtons per square metre)
• Velocities, \(w\) (metres per second)
• Erosion rates, \(E\) (grams per metres squared per second)

Portable Document Format (PDF)

The TUFLOW CATCH manual is available in Portable Document Format (PDF) by clicking on the pdf icon to the right of the navigation bar (top of the screen). This static pdf format has been provided in response to user request only and it is not the preferred means by which to access TUFLOW CATCH content. This online version is the preferred format and should be used in preference to the pdf version.

Feedback

Constructive suggestions to improve this manual are welcome, and can be emailed to support@tuflow.com.