Watershed Bounded Network Model

An advanced hydrologic modelling software package

About the model

Easy to use hydrologic modelling software

WBNM is an event based hydrologic model and calculates flood hydrographs from storm rainfall hyetographs. It can be used for modelling natural, part urban and fully urban catchments.

Model History

Behind the scenes product development

The Watershed Bounded Network Model WBNM arose out of a Master of Engineering Science project by Michael Boyd, supervised by David Pilgrim in 1973. 

30+ years

WBNM has had an extensive period of continuous development giving you assurances that the data you receive is accurate and reliable.

50+ reviews

With over 50 peer reviewed publications describing calibration, validation and use of the model WBNM is an industry tried and tested product.


Proof is in the downloads. With a extensive list of high profile instituitions & bodies using WBNM will help you achieve your modelling goals.


WBNM Engine

A stripped down and speed optimized version of WBNM, allowing wbnm to be used nationally and internationally as a highly capable hydrology engine and as the core engine underpinning ensemble and monte-carlo design flood estimation.


WBNM2023 is an upgraded extension of WBNM2022, with further improved functionality to support simulation of design storms in accordance with the provisions of Australian Rainfall and Runoff 2019 (ARR 2019).


A Graphical User Interface (WBNM GUI) is presently being developed by the authors. It is intended to be released around mid-2023, and will allow users to graphically construct a WBNM model from the interface. The GUI will also allow users to run all WBNM software from the GUI, as well as import and interrogate model results.

Credible & reliable

When you are used by over 3,000 people, you become recognised by industry.

WBNM is proud to be used by many academic institutions, government and semi-government organizations and some of the finest private flood consulting firms in Australia.

Watershed Bounded Network Model

Whilst we aim to provide as professional support as we can, we are all volunteers and have full time jobs. We have always provided our users with timely and efficient levels of support, and will continue to do so, however there will be times where day-to-day responsibilities will prevent an immediate response. We thank you for your understanding.

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