Puget Soundkeeper and Washington Environmental Council created this decision tool to determine which projects to include in the Local Stormwater Pollution Controls report. The decision tool provides examples of projects that appear to meet Structural Stormwater Control (SSC) Type descriptions from the 2019 Phase I Permit, Appendix 12 (based on the SWMMWW (the “Manual”) where appropriate), and projects that do not. This tool does not replace Appendix 12 from the Permit.
This tool is intended to assist the Department of Ecology and municipal staff in understanding why reviewers did or did not include specific projects in the final SSC project lists.
This list is not comprehensive. This list does not constitute legal advice nor should it be relied upon to determine compliance. Certain projects may constitute multiple SSC types which may not be reflected here. A project may not qualify as one type but could qualify under another type. This Decision Tool does not consider the 2019-2024 Phase I Permit SSC point system.
Type 1: New Flow Control Facilities
| Yes | No |
|---|---|
| Approved detention BMPs from Manual following design criteria | New outlet for lake or pond to maintain water level during storms |
| Detention ponds, detention facilities | Replace undersized and/or failing drain line with a larger line to drain a shallow depression |
| Retention ponds, retention facilities | New pipe to solve flooding by diverting flow to a lake |
| Bioretention if infiltrates | |
| Vaults | |
| Infiltration | |
| Sediment ponds, sediment facilities | |
| Installation of pervious pavement |
Type 2: New Runoff Treatment Facilities
| Yes | No |
| Runoff treatment facilities that meet Manual or equivalent manual design criteria or the Highway Runoff Manual, or have a GULD designation through TAPE | Maintenance activities |
| Bioretention, bioretention systems | Options analysis or feasibility analysis between treatment system types |
| Biofiltration swales, water quality swales, bioswales | Pretreatment |
| Filter vaults or water quality vaults or vault treatment systems | Alum treatment |
| StormFilters, stormwater filter systems, filter cartridge treatment facilities or systems, synthetic media filters | Descriptions that need additional detail in order to qualify and thus, on their own, do not qualify: Treatment unit Water quality facility or pond or runoff and flow control facility Water volume and flow quality BMP |
| Stormwater wetlands | |
| Landscape infiltration via underdrains | |
| Oil/water separators | |
| Wet ponds, wet pools | |
| Installation of pervious pavement |
Type 3: New LID BMPs
| Yes | No |
| Bioretention and bioinfiltration systems or facilities that meet design criteria, including swales and bioswales | Descriptions that need additional detail in order to qualify and thus, on their own, do not qualify: Rain garden Water volume & quality BMP |
| Silva cells and similar devices functionally equivalent to bioretention if they contain an 18” thick layer of qualifying bioretention soil mix (as defined by the Western Washington Stormwater Management Manual). | Detention vaults: will be type 1 only unless infiltrate, as LID BMPs must infiltrate |
| Installation or conversion to pervious pavement | |
| Dispersion | |
| Infiltration |
Type 4: Retrofit of Existing Facilities
| Yes | No |
| Install improved pump intake and controls at flow control facility that decreases peak flows or duration | Bioretention, storm filters, treatment devices, or installing other new facilities or systems |
| Retrofit of stormwater wetland, detention pond, detention facility, detention vault, wet pond, or other stormwater facility | Dam removal |
| Wetland enhancement | Berm along park wetland |
| Water quality vault retrofit | Upgrading storm sewer pipe to larger pipes |
| Channel and ravine stabilization | Descriptions that need additional detail in order to qualify and thus, on their own, do not qualify: Replace pump and aged manhole with new pump and wet vault Access road construction Alley paving project Replacement of conveyance pipe to regional flow control facility LID retrofit |
| Retrofit of slope drains | |
| Wet pond addition | |
| Berm at overflow of infiltration pond | |
| Increase pond volume and add pre-settling cell | |
| Combine and improve undersized facility |
Type 5: Property Acquisition
| Yes | No |
| Requires a permanent designation on the land to protect it from future development. Should be noted in deed. | Property acquisition of land on the river side of a levee to protect those properties from flooding |
| Acquisition of property, priority habitat, riparian habitat, or forest land | Property acquisition to protect nearshore salmon habitat |
| Acquisition for wetlands | Acquisitions without sufficient reference to how the property will be maintained or used in the future |
| Open space expansion | |
| Acquisition, demolition, then planting | |
| Property acquisition of land on the land side of a levee to permanently protect that land from development | |
| Purchase of property to perform floodplain restoration or reconnection | |
| Purchase and remove homes to allow riparian habitat in channel migration area |
Type 6: Maintenance Over $25K
| Yes | No |
| Maintenance of wet ponds, drywells, settling ponds etc. to improve treatment or performance | Berm at overflow of infiltration pond |
| Removal of material from facilities | Modify the inlets to a lake to enhance pollutant removal by repairing an existing grass-lined channel and vault |
| Control sediment loaded overflow | Capital improvement project remediation to provide additional overflow protection at an existing regional stormwater flow control facility |
Type 7: Restoration of Riparian Buffer
| Yes | No |
| Restoration of riparian forest or riparian vegetation | Wetland buffer |
| Stream buffer | Riparian restoration program |
| Riparian plantings to improve stream temps | Remove bulkhead and restore shoreline processes |
| Dam remediation | |
| Increase channel complexity and enhance riparian vegetation | |
| Descriptions that need additional detail in order to qualify and thus, on their own, do not qualify: Creating acres of off-channel habitat, then revegetating Enhancing topography, hydrology and riparian/wetland vegetation Removing sediment from stream channel to improve drainage, then revegetating to mitigate impacts Revegetating shoreline of estuary/lagoon Vegetation enhancement/ enhancing vegetation |
Type 8: Restoration of Forest Cover
| Yes | No |
| Forest restoration | |
| Woodland restoration |
Type 9: Floodplain Reconnection
| Yes | No |
| Remove structure to restore floodplain | Estuary or creek enhancement |
| Floodplain restoration | Feasibility analysis for actions to reduce flood risk |
| Setback or remove entire levee | Repair levee or revetment |
| Improve floodplain connection, conveyance or capacity | Rebuild levee in a structurally stable manner and increase local flood conveyance capacity within reach. Includes: reconstruct levee toe, install large woody debris, excavate a mid-slope bench and toe buttress revegetated with live willow layers and native riparian trees and shrubs, and stabilize the upper bank |
| Purchase of property to perform floodplain restoration | Add woody debris and structure in creek and surrounding wetlands to improve floodplain reconnection and riparian function |
| Descriptions that need additional detail in order to qualify and thus, on their own, do not qualify: Constructing a setback berm along the perimeter of a wetland and acquiring private properties to provide protection from inundation of flood waters |
Type 10: Removal of Impervious Surfaces
| Yes | No |
| Removal of fill and impervious area | |
| Asphalt removal, construction of medians with planted trees | |
| Buy and remove a repeatedly flooded home along creek. Impervious surface removed and replaced with riparian plantings |
Type 11: Other
| Yes | No |
| Enhanced street sweeping (high efficiency) in applicable MS4 service area | Decommissioning UIC wells |
| Filter vault maintenance | |
| WQ facility plans | |
| Descriptions that need additional detail in order to qualify and thus, on their own, do not qualify: Line cleaning Cleaning and inspecting existing stormwater mains |
Should you have any questions regarding our decision-making, please contact Mindy Roberts at Mindy@wecprotects.org or Alyssa Barton at Alyssa@pugetsoundkeeper.org.
Nature's Scorecard 