A model is usually needed during the design of stormwater treatments to help determine the appropriate size and design configuration, and prove that it meets minimum planning requirements.
The STORM calculator can be used to model stormwater treatments for small subdivisions, while Model for Urban Stormwater Improvement Conceptualisation (MUSIC) is used for more complex projects.
STORM calculator
The general public can use the STORM calculator to design small residential, commercial and industrial developments, ensuring they achieve the stormwater treatment objectives required by state and local government planning provisions.
It is important that the STORM calculator matches the design shown on the plans.
DEECA is currently working to update the STORM Calculator tool to assist with Water Sensitive Urban Design assessments. Once updated, Melbourne Water intends to retire the STORM Calculator that is currently available on its website.
Rainwater tank mistakes
The STORM calculator assumes that rainwater tanks are used for toilet flushing, with a water use rate of 20 litres per person per day.
A common rainwater tank mistake is to enter the whole roof area into a single row in the calculator, when only part of the roof is connected to the tank. Roof parts not connected to the tank must be entered as separate rows, otherwise the calculator will assume the whole roof is connected.
Raingarden mistakes
The size of raingardens is commonly misunderstood, with household raingardens typically being one metre high in total.
The 100mm and 300mm options in STORM refer to the extended detention depth, or ponding depth above the top of gravel mulch and below the grated cap. The following diagram of a raingarden has 100mm from the top of gravel mulch to the grated cap overflow drain.
MUSIC
MUSIC is a computer model representing a project or catchment area, the drainage connections and a series of stormwater treatments. It simulates rainfall and runoff at six-minute intervals over at least one year, and then treatment by sediment basins, wetlands and other water sensitive urban design measures.
MUSIC is more sophisticated than STORM, allowing you to adjust many design dimensions and model a series of treatments, called a treatment train.
To learn more about MUSIC, visit the following webpages:
Melbourne Water MUSIC Guidelines 2024 - Tool guidelines 2024
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Melbourne Water’s MUSIC Guideline 2024
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Melbourne Water has released an updated version of the MUSIC (Model for Urban Stormwater Improvement Conceptualisation) Modelling Guideline.
The purpose of this document is to provide guidance on modelling approaches and input parameters for MUSIC models that are submitted to Melbourne Water.
The update was developed by peer review, scientific research, and stakeholder engagement across Melbourne’s stormwater industry. It addresses industry feedback, information gaps, and incorporates recent advancements in both science and industry.
Notable changes include:
- revised rainfall data. New templates better represent rainfall patterns, including the creation of an additional template band.
- clearer guidance on sediment ponds. This will minimise the risk of designing inappropriate treatment systems.
- new guidance on high flow bypasses, overflows, wetlands with multiple inlets.
- Clarifying Melbourne Water’s position that proprietary stormwater treatment devices may not replace nature-based systems in Development Services Schemes.
The new guideline, rainfall templates, and associated maps are available here
Please note, Melbourne Water no longer accepts new models developed using the 2018 templates or guidance.
Clearwater and Stormwater Victoria hosted an information session covering the new guideline and changes, you can find the recording on the clearwater website MUSIC Modelling Guideline 2024 - Webinar 1 May 2024.
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MUSIC Auditor
MUSIC Auditor is a tool used by Melbourne Water and councils to assess MUSIC models and check they comply with Melbourne Water's MUSIC guidelines.
You can check your model before you submit it: