Swale

Stormwater treatment doesn’t have to be hidden—swales are a great example of how green infrastructure can be both functional and attractive. Also known as bioretention strips, filter strips, infiltration strips, channel drains, or grassed channels, swales are broad, vegetated channels designed to direct and slow stormwater runoff across a site.

Swales guide stormwater through gently sloped, grassy channels, allowing water to slow down and spread out. As runoff moves through the swale, sediments, nutrients, and contaminants are filtered out by the vegetation and soil before the water is discharged to downstream stormwater systems or natural waterways. Some swales are lined with impermeable liners to direct filtered runoff, while others use rocky linings to further slow fast flows and prevent erosion.

Routine maintenance is essential to keep swales functioning effectively. Over time, sediment, litter, and organic matter can build up, clogging the channel and reducing its ability to filter pollutants. Weeds, erosion, and unhealthy vegetation can also impact performance and appearance. Regular care ensures your swale continues to provide both environmental benefits and visual appeal.

At Dutton Stormwater, we provide expert swale maintenance services across New Zealand. Our team inspects, removes debris, manages vegetation, repairs erosion, and ensures your swale is operating efficiently and in line with council requirements.

Swales typically require maintenance every six to twelve months, depending on site conditions, vegetation type, and pollutant loading. During each service, we provide a detailed maintenance report with any recommendations to keep your swale performing at its best.