RORB software for runoff routing

The RORB runoff routing software was developed within the Water Group of the Department of Civil Engineering by Eric Laurenson and Russell Mein. The latest version (RORB Version 6.18, 2012) is the result of a collaboration between Monash University (Russell Mein) and Sinclair Knight Merz (Rory Nathan), with support from the Melbourne Water Corporation. It is now freely available in the public domain for download by those who wish to use the program. (RORB Version 6.18 is  available for download)

In addition, ‘MiRORB’ is a tool which uses the GIS package MapInfo to generate input data for use with RORB. Developed by SKM with the support of Melbourne Water, MiRORB version 1.2 (August 2013) is now freely available for download.

About RORB

RORB is a general runoff and streamflow routing program used to calculate flood hydrographs from rainfall and other channel inputs. It subtracts losses from rainfall to produce rainfall-excess and routes this   through catchment storage to produce the hydrograph. It can also be used to design retarding basins and to route floods through channel networks. The program requires a datafile to describe the particular features of the stream network being modelled and is run interactively. It can be used both for the calculation of design hydrographs and for model calibration by fitting to rainfall and runoff data of recorded events.

The model is areally distributed, nonlinear, and applicable to  both urban and rural catchments. It makes provision for temporal and  areal variation of rainfall and losses and can model flows at any number  of gauging stations. In addition to normal channel storage, specific modeling can be provided for retarding basins, storage reservoirs, lakes or large flood plain storages. Base flow and other channel inflow and outflow processes, both concentrated and distributed, can be modeled. RORB Version 5 and above is fully Windows compatible, with considerable enhancements over Version 4. The new features include the provision to vary parameters over sub-catchments, additional features in the specification of design storms and special storages, the facility for multiple (or batch runs) for a range of ARI and/or duration, extended interactive graphics capability, and Monte Carlo simulation.

‘MiRORB’ is a tool which uses the GIS package MapInfo to    generate input data for use with RORB. Developed by SKM with the support  of Melbourne Water, MiRORB allows the creation of RORB models using the MapInfo GIS   environment. RORB model features such as subareas, reaches, nodes, and special   storages can be drawn interactively within MapInfo, automatically determining reach lengths, reach slopes, catchment areas, and impervious fractions. After   drawing the model features, they are then compiled into a fully functional RORB model, ready for immediate use within RORB. The key advantages of MiRORB are:

  • Typographical errors between GIS data and RORB models are  eliminated.
  • There is a direct 1-to-1 match between the spatial data and  the RORB model, ensuring the model represents the catchment precisely as the user intended.
  • With a single command, a RORB model can be prepared with all  new impervious fractions from the GIS source data, allowing very quick comparison of urban development scenarios.
  • A range of tools make it easy to use pre-existing spatial  data such as subarea boundaries to develop new RORB models.

To use the tool, you must have MapInfo version 8.5 or later, and  RORB version 6.0 or later.


RORB Ver. 1, a general runoff routing program for use on rural catchments was released in 1975 (as a BASIC program called RORT).

RORB Ver 2 was released in 1978 in both a BASIC and a FORTRAN version, the latter being simply a translation of the former. That version extended the usage of the program from rural to urban or partly rural and partly urban catchments and also introduced some other new capabilities.

The third version, released in 1981, further enhanced the  program's capabilities, improved its portability, and increased its ease  of use. It was completely rewritten in standard FORTRAN 66 code.

Version 4, released in 1987, was functionally the same as  Version 3 but made use of the graphical capabilities of personal  computers. A Windows Interface, added in 1997, gave significant  enhancements, particularly in generation of   design storms, and  graphical output.

Version 5 (2005) removes the DOS dependency completely, by  including the FORTRAN code for RORB as a subroutine in a Windows  environment; this adds much to the usability of the program. New  features (eg Monte Carlo simulations, and   batch runs) are important  additions.

Version 6 (2008) This version incorporates a Graphical Editor  (GE) which enables users to create catchment files based on a graphical network of nodes   and reaches. The intent of the GE is to reduce the level of effort required to   create a catchment file, and to improve user's ability to understand, review, and modify catchment details. It enables users to visually understand the   catchment layout, and input appropriate data; when this is done, the GE will   automatically write the entire catchment file. Further advances released as part of version 6.14 include the ability to model user-defined rainfall intensity-frequency-duration data. The program is backwardly compatible and all   earlier versions of data files can be run without modification. The user manual has also been revised and updated.

MiRORB v1.1 (January 2010) After some initial testing within Melbourne Water during 2008 and 2009, this is the first public release of the MiRORB tool. The tool was specifically designed for the creation of RORB models using the MapInfo   GIS environment.

Computer Requirements

RORB v5 and above is designed for users running Windows 95 and above. It is a native 32-bit Windows application based on the Winteracter Graphical User Interface (GUI) and Fortran95 programming environments. In essence, the full functionality of the existing RORB model has   been retained, as it runs as a subroutine to the Windows GUI, but combined with   extra capabilities as noted above.

Installation is most easily accomplished by running the  installation program   supplied. It should be noted that this program  does not rely on, nor interact   with, any other windows programs.


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