What does the 'treatment train' analogy refer to in the context of stormwater management?

The 'treatment train' analogy in stormwater management refers to a series of treatment steps that work together to manage and improve the quality of stormwater runoff before it is discharged into receiving waters. This concept embodies the idea that multiple practices can be interconnected, creating a comprehensive system where each step contributes to filtering, managing flow, and reducing pollutants in stormwater.

For example, the treatment train might begin with source control measures such as green roofs or permeable pavements that reduce runoff volume. This could be followed by detention basins or bioretention areas that temporarily store stormwater and allow for sedimentation and biological processes to treat the water. The final steps might involve wetland restoration or advanced treatment systems that further enhance water quality.

This approach emphasizes that relying on a single method for stormwater management may not be as effective as a network of practices designed to work in concert, which highlights the versatility and adaptability needed in managing stormwater in various environments. Such a multi-step strategy is essential in achieving desired outcomes like reducing flooding, improving water quality, and ensuring sustainable urban development.