December 10th, 2020

We are receiving enquiries about the impact of Innovyze recently discontinuing XPRAFTS and how this will affect DRAINS RAFTS.

RAFTS is one of many hydrological models available in DRAINS. Watercom developed the RAFTS Hydrological model equations in DRAINS using the non-linear runoff routing procedures described in ARR 87. It does not use XPRAFTS. Watercom will continue to support the RAFTS model in DRAINS.

November 16th, 2020

A new version of DRAINS is available that allows users to lock pit loss coefficient (Ku) values when revising coefficients, useful when modelling GPT devices.

The former Premium hydraulic model has now been renamed to the ‘Full unsteady hydraulic model’, while the former Standard hydraulic model has been renamed to ‘Lite hydraulic model’.

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:

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:

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.