What is a vegetated swale?

A vegetated swale is an open channel that collects stormwater and allows it to infiltrate into the ground. The grass or plants covering the side slopes and bottom provide a filtration surface for the water and help slow the flow rate. Many swales have an underdrain pipe to manage larger storms.

What is a wetland swale?

Wet swales occur when the water table is located very close to the surface or water does not readily drain out of the swale. A wet swale acts as a very long and linear shallow biofiltration or linear wetland treatment system. Wet swales do not provide volume reduction and have limited treatment capability.

What is a bioretention swale?

Bioretention swales are shallow, vegetated, landscaped depressions with sloped sides. They are designed to capture, treat and infiltrate stormwater runoff as it moves downstream.

What is a grassed swale?

A grass swale is a stable turf, parabolic or trapezoidal channel used for water quality or to convey stormwater runoff, which does not rely on the permeability of the soil as a pollutant removal mechanism. The total suspended solids (TSS) removal rate for a grass swale designed according to this chapter is 50%.

What is a vegetated filter strip?

Vegetative filter strips are land areas of either planted or indigenous vegetation, situated between a potential pollutant-source area and a surface-water body that receives runoff. The term ‘buffer strip’ is sometimes used interchangeably with filter strip, but filter strip is the preferred usage.

Are swales effective?

Vegetated swales are most effective on soils that allow infiltration. If infiltration is desired, the underlying soil drainage rate should exceed 0.5 inches per hour. Amended topsoil can be installed to improve infiltration and retention of runoff.

Is swale a ditch?

Swale drains are broad, shallow ditches that can be lined with grass, vegetation, or rocks. It’s a more natural way to help drain yards to prevent flooding, puddling, and erosion.

Why are swales used?

Swales, like any catchment, are a means of stopping water runoff, especially from roads and hard surfaces, and putting it to use rather than having it drain away. Using swales for these reasons can prevent both floods and droughts, which make them a pretty powerful tool.

What is bioretention How does it work?

Bioretention is an important technique that uses soil, plants and microbes to treat stormwater before it is infiltrated or discharged. Bioretention “cells” are shallow depressions filled with sandy soil, topped with a thick layer of mulch, and planted with dense vegetation.

How big should my swale be?

There are no hard rules about the size of a swale, but the bigger it is the more water it can absorb during a rainstorm. Six- to 12-inches deep and 3- to 4-feet wide are typical dimensions. Smooth out the shape of the berm with a hard metal rake to form a planting bed.

How much does a filter strip cost?

Filter strips are one of the least expensive stormwater runoff control measures you can implement. Seeding costs can range from $20 to $100 per 1,000 square feet with sod costing $125 per 1,000 square feet ($0.40 to $6.25 per linear foot for a 20- to 50-foot wide strip) depending on site conditions.