Southwest Environmental Limited
Level 26, 1 Bligh Street, Sydney, NSW 2000, Australia


Environmental Consultancy Services to Industry, Business and Individuals

Stormwater Management

In any new development particularly urban ones, it is important to manage storm water. We are environmental consultants that can work up a storm water management strategy for your site, producing plans and reports to support you development application.

BASIX (Building Sustainability Index)

There are two main requirements to consider when managing stormwater as part of your development or building project in the Sydney drinking water catchment. All new residential development in NSW must meet requirements of BASIX, the Building Sustainability Index.

 BASIX requires new residential development to be water and energy efficient. All development applications must be accompanied by a BASIX certificate that addresses the attenuation and re-use of stormwater. Proposed developments in the Sydney drinking water catchment will be required to  meet the standard of a neutral or beneficial effect on water quality (NorBE).

To realise this elevated water quality standard, landowners and developers will be required to use extra mitigation measures than required by BASIX. This requirement originates from potential of construction activities to contaminate NSW's drinking water supplies. Additionally; because of the potential of any new developments to increase the amount of stormwater or wastewater created by a proposal. Increases in stormwater can also affect drinking water quality.

 The requirements you will need to follow for NorBE vary depending on: the size of your development - large scale or lot-size the stage of your development - during construction or after construction

Southwest Environmental can manage consultations with local council in the planning stages of your development, to ensure your proposed design, and construction of stormwater control measures, will have a NorBE on water quality and meet other requirements.

MUSIC (Model for Urban Stormwater Improvement Conceptualisation)

MUSIC stands for "Model for Urban Stormwater Improvement Conceptualisation". If you wish to learn more, the key text is: Using MUSIC in Sydney's Drinking Water Catchment (PDF, 5311.16 KB), a manual to assist consultants prepare MUSIC stormwater quality models in order to achieve a neutral or beneficial effect on water quality for proposed urban and rural land use developments. Inputs for the modelling process are dervived from the climate zone key map for rainfall zones in the project area.

Small Scale Stormwater Quality Model (S3QM)

The small scale stormwater quality model (S3QM) aims to estimate stormwater pollutant creation and the performance of stormwater treatments from smaller, less complex proposed developments.

WaterNSW will accept the use of the S3QM tool when gauging stormwater impacts for small proposals of less than 2,500 square metres. Visit: S3QM support for guidance on creating models, and case study examples.