What Stormwater Option is Best for Me?

Stormwater SystemDrainage PlanBasic & Post-Construction SW Mgmt PlansHyrdologic Soil Group(3)Depth to Seasonal High Groundwater
LID: Reduce Imperviousness Yes Yes All All
LID: Avoid Soil Compaction Yes Yes All All
LID: Maximize Native Vegetation Yes Yes All All
Rain Barrels     All All
Rain Gardens Yes   All All
Drip-Edge Filters Yes   All All
Downspout Disconnection Yes   All All
Soils Restoration Yes Partial (4) All All
Surface Soil Filter   Yes A-C Install above
Subsurface Sand Filter   Yes A-C Minimum 1 ft
Gravel Wetland   Yes C-D All
Storage and Reuse System   Yes All All
Americast Filterra® System(2)   Yes A-C See Specs
WA DOT Media Filter Drain(2)   Yes A-C All
Kristar FloGard Perk Filter®(2)   Yes A-C See Specs
Porous Asphalt(1)   Yes(1) N/A N/A
Porous Concrete(1)   Yes(1) N/A N/A
Green Roof(1)   Yes(1) N/A N/A


  1. Research indicates that these systems perform very well, but typically have higher cost and complexity. These systems should receive favorable review if included as part of a development application, however, detailed design specifications are not included in this manual.
  2. All systems certified by State of Washington Technology Assessment Protocol - Ecology (TAPE) "General Use" (GULD) for "Enhanced" (metals) or "Phosphorus" pollutant types are recommended for South Portland Basic and Post-Construction Stormwater Management Plans. Check to see if new systems have been certified with Washington TAPE-GULD program at these websites:
    Note that "Pilot Use" or "Conditional Use" designations under that program are not recommended.
  3. Generally speaking, soils in A group are fast draining (sands and gravel), while soils in D group are very slow draining (high clay content). Soil Hydrologic Groups are defined at http://nesoil.com/hydrologic.html or through the Natural Resources Conservation Service. Please visit the City's GIS viewer to determine the soil types for your property.
  4. Soil Restoration is a recommended treatment option for non-impervious areas (for example, lawns and landscaping) of projects which need a Basic or Post-Construction Stormwater Management Plan.