Structural stormwater Best Management Practices

In a watershed scale stormwater management approach, structural BMPs are used for on-site and regional treatment and after prevention and source control BMPs have been employed. Source:CDM Smith.

A structural stormwater Best Management Practice (BMP) is defined in the MS4 General permit as "a stationary and permanent BMP that is designed, constructed and operated to prevent or reduce the discharge of pollutants in stormwater".

1. Green roofs
2. Permeable pavement
3. Trees
4. Bioretention
   1. Rain garden: see Bioretention
5. Infiltration (infiltration trench, basin, dry well, and underground infiltration)
6. Filtration
   1. Dry swale (Grass swale)
   2. Wet swale (wetland channel)
   3. High-gradient stormwater step-pool swale
   4. Sand filters
7. Iron enhanced sand filter (Minnesota Filter)
8. Stormwater ponds
9. Stormwater wetlands
10. Manufactured treatment devices
11. Pretreatment practices
    1. Vegetated filter strips
    2. Pretreatment - Hydrodynamic separation devices
    3. Pretreatment - Screening and straining devices, including forebays
    4. Pretreatment - Above ground and below grade storage and settling devices
    5. Pretreatment - Filtration devices and practices
    6. Pretreatment - Other pretreatment water quality devices and practices
12. Chemical treatment

• Examples of structural BMPs.
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  Bioretention (rain garden)

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  Permeable pavement

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  Green roof (Image Courtesy of The Kestrel Design Group, Inc.)

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  Iron enhanced sand filter (Photo courtesy of Barr Engineering)

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  Vegetated swale

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  Vegetated filter strip. Photo courtesy of Alisha Goldstein, U.S. EPA.

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  Pretreatment Manhole Sump [Ramsey Conservation District, 2017].