Approved Facility Types

Untitled Document

Exhibit 2-1: Stormwater Management Facility Application Table

Stormwater Management Facility Type Credit Given with Associated Design Approach
Pollution Reduction Flow ControlDestination
Eco-roof & roof gardenSimplifiedSimplifiedNA
Pervious pavementSimplifiedSimplifiedSimplified/Presumptive (4)
Contained planterSimplifiedSimplifiedNA
Tree creditSimplifiedSimplifiedNA
Infiltration Stormwater planterSimplified (1)SimplifiedPresumptive
Filtration Stormwater planterSimplified (1)SimplifiedNA
Swales < 15,000 sq-ft impervious areaSimplified (1)NAPresumptive
Swales > 15,000 sq-ft impervious areaPresumptiveNAPresumptive
Level SpreaderPresumptive (7)Presumptive (7)Presumptive (7)
Vegetated filter stripSimplifiedNASimplified (5)
Infiltration Rain GardenSimplified (1)SimplifiedPresumptive
Filtration Rain GardenSimplified (1)SimplifiedNA
Sand filterSimplified (1)SimplifiedPresumptive
Wet pondPresumptiveNANA
Extended wet detention pondPresumptivePresumptiveNA
Dry detention pondPresumptive (3)PresumptiveNA
Treatment wetlandPresumptivePresumptiveNA
Manufactured treatment technologyPerformanceNANA
Structural detention facilityNAPresumptiveNA
Spill control manholePresumptive (2)NANA
Soakage trenchNA (6)PresumptivePresumptive
Infiltration sumpNAPresumptivePresumptive

Exhibit 2-1 Notes:

(1) The Presumptive Approach may be used to downsize these Simplified Approach facilities.

(2) Spill control manholes receive credit for oil removal only; additional pollution reduction facilities will be required to meet basic water quality management.

(3) Vegetated or grassy swales must be integrated into the bottom of dry detention ponds to receive pollution reduction credit.

(4) Pervious pavements in NRCS soil types A or B meet destination requirements when designed using the SIM Form.

(5) Vegetated filter strips designed using the SIM Form may be used for destination for some small projects as outlined in Chapter 2 of the Stormwater Management Manual.

(6) Soakage trenches, having a minimum 18-inch layer of sand for filtration installed below the soakage trench and designed per "Soakage Trench" facility design requirements, may meet pollution reduction requirements.

(7) Level spreaders must include dedicated filtration buffer in the design for management credit.