A treatment train is a series of stormwater management systems that work together to clean water as it moves through the environment. Each stage targets different types of pollutants.

By combining WSUD systems in the right order, treatment trains help keep waterways clean, reduce stormwater volumes, reduce costs and help each part of the system work more efficiently.

Below are some common examples of how different WSUD systems can be combined to form an effective treatment train.

Sediment basin and constructed wetland

Sediment basins capture finer sediment like sand and gravel before water flows into downstream WSUD systems like wetlands or bioretention areas. Constructed wetlands then provide further treatment through a series of densely planted ponds that filter and improve water quality.

Gross pollutant trap (GPT) and swale

GPTs remove litter and coarse sediments. Stormwater then enters WSUD assets like swales, wetlands or other measures where dense planting and / or grass slows, filters and cleans stormwater before it reaches creeks, lakes or the ocean.

Rainwater tank and raingarden

Rainwater tanks collect runoff from hard surfaces like roofs, reducing the amount of stormwater entering waterways. The stored water can be reused for garden irrigation, toilet flushing, and other non-drinking purposes. Tanks can also be connected to raingarden beds that filter runoff from the lot, remove pollutants, and improve water quality before it leaves the site. This approach reduces maintenance needs and improves overall system performance.