1.   Purpose and Objectives

     An event based runoff routing model suitable for integrated catchment management and flood forecasting.

2.   Description

     URBS-CM is a non-linear runoff-routing networked model of sub- catchments based on centroidal inflows. Three routing models are available to describe catchment and channel storage routing behaviour. The Basic model is a RORB-like model (Mein, R.G., E.M. Laurenson, and T.A. McMahon  
(1974) Simple Nonlinear Model for Flood Estimation, Journal of Hydraulics Division, American Society of Civil Engineers, Vol 100, 1974, No.HY11) where stream length (or derivative) is assumed to be representative of both catchment and channel storage. The Combined model combines the sub-
catchment area and stream length or derivative to be representative of the catchment and channel storage, whereas the Split Model separates the channel and catchment storage components of each sub-catchment for routing purposes. Irrespective of the model used, each storage component is 
conceptually represented as a non-linear reservoir and Muskingum routing is used for channel routing.
 
     The URBS-CM model includes the following features:

     (a)  streamlined access to hydrological data;
     (b)  easily interpretable text and graphics results;
     (c)  calculated heights as well as discharges;
     (d)  access to output from water balance models;
     (e)  better modelling of hydrological behaviour through:
          (i)   splitting the catchment and channel routing components,
          (ii)  allowing for the use of different loss models, 
          (iii) splitting of loss model into pervious and impervious 
                components, and
          (iv)  accounting for the effects of urbanization;
     (f)  sediment wash off and deposition modelling;
     (g)  traffic disruption costs due to flooding;
     (h)  on-site detention analysis;
     (j)  assessment of the impacts of roofwater retention;
     (k)  provision of efficient detention basin design routines;
     (l)  batch processing to minimize runtime and maximize review time;
     (m)  output files readily imported into commercial spreadsheets.

3.   Input

     Catchment specification, recorded river flows or heights, rainfall data and rating curves if river height data are either input or required as output. The catchment specification contains the subcatchment descriptions and river reach details used to characterize the hydrology of the river catchment being studied.

4.   Output

     Screen plots of observed and modelled hydrographs and rainfall hyetographs. A series of output files are generated containing depths of excess rainfall, observed and modelled river  discharges and heights (if rating tables are present), sediment washoff and traffic disruption information.

5.   Operational requirements and restrictions

     The software operates on IBM compatible microcomputers. A 486MHz computer with VGA screen is adequate to run the package. No additional software is required to run the package. The package does not require specialized installation. A user manual is provided but specialized hydrological knowledge is required to use the model effectively.

6.   Form of presentation

     The package is provided as a suite of PC-DOS/Windows 32 bit console executable programs written in the C language. A comprehensive user manual and example files are included. The language used throughout is English.

7.   Operational experience

     The model has been used successfully for both design and operational flood hydrology in Australia. The URBS model is included as one of the models used by the Australian Bureau of Meteorology for flood forecasting. The model should be applicable to other parts of the world.

8.   Originator and technical support

     The model and software has been developed by Don Carroll over a number of years. Development is ongoing and new versions of the software are released as developments occur. The software package is released as Shareware and formal support for its use is not available. The manual and examples should be sufficient to guide the user. Some guidance on the use of the model by the Bureau of Meteorology is available from the HNRC for Australia.

9.   Availability

     From the HOMS National Reference Centre for Australia, or from 
     Don Carroll, 43 Suncroft St., Mount Gravatt QLD  4122, AUSTRALIA
     Email: don_carroll@iprimus.com.au
     Phone/Fax: +61-7-34200204

10.  Conditions on use

     The use of URBS in any studies should be acknowledged in any reports or papers resulting from those studies.

     Use of URBS is conditional on obtaining a license for use from Don Carroll. The license is on a single site multi-user basis.