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    Bioswales are a common green stormwater infrastructure in cities. Composed of native vegetation, these plots of land vary greatly in size and location. Often found along edges of sidewalks, bioswales are designed to catch and treat runoff from storm events. Composed of a soil filter system and vegetation, runoff can be temporarily stored and often flows into an underdrain and continues downstream.

    Bioswales are used for drainage areas that are less than half an acre. Placed in heavy foot traffic areas, these plots of land reduce erosion and slow runoff as the stormwater is filtered. They can be home to grasses, bushes or trees depending on the environment.

    In some cases, an underdrain will be built beneath the bioswale, this is dependent on the soil permeability. Once runoff filters through the bioswale, it will continue downstream by way of the underdrain. Bioswales are not intended to hold runoff for longs periods of time and should be filtered in 72 hours.

    Bioswale Management


    Bioswales are similar in design to bioretention cells. These systems are integrated into city infrastructure, intended to filter runoff, and remove pollutants like sediment, metals and hydrocarbons. A bioswale can also reduce peak runoff rates, increase stormwater infiltration, or groundwater recharge, and manage water volumes during storm events.

    Bioswale systems provide water protection, water conservation, and stormwater quality benefits. Some of the benefits of bioswale include:

    • Efficient and effective pollutant removal through infiltration, plant absorption, and often using engineered media
    • Reduction of runoff and stormwater volume control from the developed site
    • Provides groundwater recharge
    • Utilization of native forest ecosystem structure and landscape processes to increase water quality and biodiversity
    • Creates natural habitats and greenspace and improves site aesthetics
    • Flexibility in design layout and scale, which allows it to fit in most landscapes and development sites
    • Good option for retrofit of existing infrastructure
    • Relatively low maintenance
    • Adds aesthetic appeal to the sites


    As the green stormwater infrastructure experts, AQUALIS has significant experience in the rehabilitation and long-term maintenance of bioswale areas. Our goal is to design and implement bioswales that effectively filter pollutants out, slow stormwater runoff, reduce erosion, create and restore habitat for native vegetation and wildlife and improve water quality in a natural, aesthetically pleasing manner.

    Insights from AQUALIS