A Stormwater Management Report (SWM Report) is a key engineering submission required for development applications that explains how a site will manage rainwater runoff safely and meet municipal requirements.

It compares existing (pre-development) and proposed (post-development) conditions and outlines how the project will control flooding risk, runoff flow, water quality, and infiltration. The report includes modeling and design analysis to confirm the site can handle major storms (including extreme events) without impacting surrounding properties or infrastructure.

Key elements include:

• Controlling peak runoff (e.g., storage tanks, rooftop storage)

• Improving water quality (treatment systems)

• Managing infiltration and water balance

• Safe drainage systems and overflow routes

• Checking capacity of existing municipal infrastructure

The goal is to ensure the development does not increase flood risk, protects downstream systems, and meets approval requirements, while supporting the overall site design and permitting process.