Watercom Customer Support

Home | DRAINS Download | Pipes | Training ]



March 31st, 2020

A new version of DRAINS is available that allows the import of very frequent and rarer storms. This includes storms from 12 EY to 1 EY and 1 in 200 to 1 in 2000 years.


September 13th, 2019

A new version of DRAINS is available that allows users to define IL-CL subcatchment areas into three categories: Effective Impervious Area (EIA), Remaining Impervious Area (RIA) and Pervious Area (PA).

RIA is routed through PA, allowing a more rational treatment of Initial and Continuing Losses, and lets you clearly specify different losses for impervious and pervious surfaces. It also provides clear definition of Total Impervious Area (TIA) considered in a catchment.

Refer to the DRAINS Help system for more information.


July 19th, 2019

A new version of DRAINS is available that allows the import of Pre Burst rainfall data from the ARR Data Hub. This includes Transformational Preburst Depths for NSW OEH requirements to calculate the Probability Neutral Burst Initial Loss and Median Preburst Depths for other areas.

Refer to the DRAINS Help system for more information.


May 16th, 2019

A new final version of ARR is now available.  In short, key ARR 2019 updates include removing 'Draft' from the guideline, the completion of Book 9, reflection of current climate change practice, improvements to the ARR web-based user experience, and now the availability of the document as a PDF.  Refer to the ARR website for more information: arr.ga.gov.au

The ARR Data Hub has also been updated. Nationally the main update includes slight adjustments to Climate Change Factors. For NSW, specific revisions have been made to applying IL-CL values & pre-burst rainfall depths following the advice of NSW Office of Environment & Heritage. Refer to the ARR Data Hub for up to date information and guidance: data.arr-software.org

A new version of DRAINS is now available that incorporates ARR2019 procedures.


January 2019

A final draft of Chapter 6, Book 9, of ARR 2016 was released in January 2019.  New in this draft is the advice to use the published pre-burst rainfalls for the 60 minute rainfall burst duration for all burst durations less than 60 minutes.  This means the Initial Loss - Continuing Loss model recommended in ARR 2016 can now be used for urban drainage work.  DRAINS has provided the ARR 2016 procedures since January 2017.


February 17th, 2017

Mark Babister advises that his firm WMA Water is now working on providing pre-burst rainfall depths for storm bursts of less than 1 hour duration.  This means that we will be able to use the Initial Loss - Continuing Loss Model for urban drainage work. 


January 16th, 2017


A new version of DRAINS is now available that incorporates ARR2016 procedures.  It includes a new Initial Loss - Continuing Loss Model, use of IFD 2016 data from the BOM web site, and use of ARR 2016 rainfall pattterns from the ARR data hub.  Please refer to the built-in DRAINS help system for more detail (start with the Recently-added features topic).


February 3rd, 2016

We intend to add procedures from Australian Rainfall and Runoff 2016 to DRAINS as they become available, and to feature them in our workshops.  The material released at www.arr.org.au by Engineers Australia includes an overview of new design rainfall patterns, hydrological losses, urban catchment land uses and other changes.  Use of the rational method is discouraged, and new design rules will likely relate to ‘ensembles’ of design storms.  Not enough information is available at present to implement these new procedures in DRAINS. 

June 28th, 2014

The design procedure in DRAINS has been improved to produce more economic designs.

The premium hydraulic model now allows overflow routes from a node in a channel system.  This allows quasi 2D modelling of systems where flow spills out from a node and flows in a new second direction when the water level rises sufficiently.

August 12th, 2013

Numerical stability in DRAINS was greatly improved.

March 1st, 2013

A fixed reporting time step of 0.1 minutes was introduced to allow smaller files.  DRAINS now runs under Windows 8 and later.