DEFINITION
Bioretention measures are important to collect, cleanse and infiltrate water on site. Porous materials (shown in the illustration below) are installed at the bottom of the swale. Typically covered with 40-60cm of organic material mixed with local soil. This mixture acts to store collected water while being absorbed. This process can be further progressed through the installation of deep rooting native plant variates.

A bioswale or vegetated swale is a form of bioretention used to partially treat water quality, attenuate flooding potential and convey stormwater away from critical infrastructure. These systems are linear, with width to width dimensions much greater than the more typical 2:1 applied to bioretention cells.
(Source: Florida Field Guide to Low Impact Development)


AKA
bioretention swale, conveyance swale, bioditch, vegetated swale, dry swale, wet swale, degree of treatment

PERFORMANCE CRITERIA
length, slope, cross-section area, soil depth, quantity of stormwater intercepted and/or treated

ILLUSTRATION


How to fix the desert and remove salt from the ground with a swale


What's a swale?


CASE STUDIES
High Point, Seattle, Washington
Olympic Sculpture Park, Seattle, Washington
Waterworks Gardens, Renton, Washington
Xochimilco Ecological Park, Mexico City, Mexico
8th Avenue "Industrial Strength" Natural Drainage, Seattle, WA

ADDITIONAL RESOURCES
Testing onDavis soil, comprised primarily of lavarock
Testing a Bioswale to Treat and Reduce Parking Lot Runoff