What Stormwater Option is Best for Me?
|Stormwater System||Drainage Plan||Basic & Post-Construction SW Mgmt Plans||Hyrdologic 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|
|Soils Restoration||Yes||Partial (4)||All||All|
|Surface Soil Filter||Yes||A-C||Install above|
|Subsurface Sand Filter||Yes||A-C||Minimum 1 ft|
|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|
- 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.
- 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.
- 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.
- 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.