We can’t know exactly how much rain will fall tomorrow, next week or next year. But without knowing what might happen, it is very hard to make informed decisions with our precious water resources.

That is where models come in. Specifically, hydrological models.

Ovens River, image credit North East CMAImage: Ovens River, North East CMA

Hydrological models can closely simulate real-life river and the systems they supply, giving water experts valuable information about how much water there might be and how it might move through the systems.

The models take in evidence and data about what has happened before. They consider information about how much water irrigators, industries, cities, and towns use. With this information, they can simulate floods and/or drought, among other scenarios. In addition to this, they can represent how a river flowed under natural conditions and they can be used to predict the impacts of climate change on our water resources. We’re doing this in all our rivers, including the Thomson River.

These simulations help us to understand the possible scenarios that may occur in the future and the consequences of any changes to the river and water supply systems. This information helps the Victorian Government and other decision-makers to plan for the future and make sure enough water is in the rivers and in the right areas for the community and the environment to use and drink.

Watch this short video to learn more about how modelling helps us to manage our water resources

Case studies

Available modelling tools

The Department of Environment, Water and Planning (DELWP) contributes to developing and maintaining the following tools on behalf of the Victorian water industry.


The Department contributes to the development and maintenance of the new surface water modelling platform, Source, developed by eWater on behalf of state and federal Australian Governments. In addition, the Department has developed a strategy to transition from the historically used REALM software to Source software. Download and see more information.

As Source models are developed, reviewed and deemed fit for purpose, they take the place of the existing REALM models used for modelling Victorian water resource systems.


REALM (Resource ALlocation Model) can simulate both simple and large complex water supply systems. The REALM software is available for download however, the Department is no longer investing resources in REALM enhancements or upgrades, as Victoria is in the process of transitioning to Source software. Download and see more information.


The Department has contributed to developing and maintaining the specialist farm dam impact estimation software, STEDI. STEDI, which stands for Spatial Tool for Estimating Dam Impacts, is a Windows-based program used to simulate farm dams' impact on streamflow. Download and see more information.

More information

Understanding groundwater

Groundwater is an important part of Victoria's water supply. It is critical to create secure water supplies to meet growing food and fibre production, for drinking water supplies and to protect environmental values. Download and see more information.

Page last updated: 17/05/22