Sidewalk Stormwater Management Practices

The most common type of Stormwater Management Practice is typically a planted area located along the curb of a sidewalk, graded to capture stormwater, and planted with an understory of shrubs and herbaceous material, and sometimes trees. Inlet structures such as curb cuts and grates allow for stormwater from the adjacent roadway to enter the planted area and overflow to exit. Consisting of ROW Rain Gardens, Bioswales, Greenstrips, and Infiltration Basins, the city will build and maintain these practices within DEP Priority Areas; see the DEP Green Infrastructure Contract Areas and MS4 Drainage Areas map on the Stormwater Management Practices page.

Dean Street, Brooklyn
Lafayette Avenue, Bronx

Benefits

See Benefits of Plantings in the ROW in the Introduction

  • Reduced stormwater entering sewers during storms
  • Can help to improve water quality in local waterways
  • Healthier plants and greater survival rates when appropriate plants are used
  • Can improve street drainage and may reduce ponding on streets and/or sidewalks

Considerations

See General Guidelines

  • Designers should perform environmental due diligence to ensure green infrastructure installations will not exacerbate preexisting subsurface contamination, including, but not limited to, researching current and past uses of the site, and reviewing publicly available local, state, and federal databases; additional environmental analysis, and potentially site remediation, may be necessary
  • Refer to DEP's latest Procedure Governing Limited Geotechnical Investigation for Green Infrastructure Practices. Coordinate with DEP on geotechnical results to ensure that stormwater control practices are appropriate for the proposed location
  • Retrofitting existing plantings may be feasible if there is limited grade change and in situ soils are appropriate; special care must be given to tree roots; existing species must be able to tolerate higher levels of water
  • Plants should tolerate salts, sediment, contamination, and highly variable levels of water availability
  • Due to existing grading and/or the crown of the road, stormwater installations along the gutter are ideal for stormwater capture, while installations in the center of the road will not capture significant volumes of water unless the road can be regraded
  • Avoid in areas adjacent to retaining structures, structural foundations, critical infrastructure, or on roadways elevated atop a retaining wall structure; cannot be sited within 25 feet of above or below-ground MTA structures
  • Leaves, litter, and other material may clog inlets/outlets and could impact overall performance and aesthetics of the installation. Locations with heavy sediment or trash/ debris loading will require frequent cleaning and should be avoided
  • Stormwater management practices funded and approved by DEP will be maintained by DEP, all other installations are encouraged, but will require a maintenance agreement

Application

  • Install in all areas with Tree Beds, Roadway Plantings, Sidewalk Plantings, Plaza Plantings, and Limited-Access Arterial Plantings
  • ROW Bioswales are the most frequently used and generally mimic the siting criteria used for Tree Beds
  • ROW Rain Gardens are typically used where there is shallow bedrock or groundwater and have the same siting criteria as Bioswales
  • ROW Greenstrips may be used where sidewalks are narrow, but are generally not preferred
  • ROW Infiltration Basins are used in areas with narrower sidewalks and/or higher pedestrian volumes where plants are not feasible or an existing grass strip should be maintained; they are not recommended for areas where vehicles frequently mount the sidewalk
  • Installations can be pursued in partnership with DEP, Parks, or another maintenance partner

Design

  • DEP Standards for the ROW Bioswale, Rain Garden, and Greenstrip are available on the DEP website
  • Use canopy trees, low shrubs, and groundcover to maintain visibility
  • Surface treatment may be plantings, lawn, or concrete depending on context and community feedback
  • A minimum 8-foot clear path must be maintained in areas with high pedestrian traffic and a 5-foot minimum clear path in areas with low pedestrian traffic. DOT may require a greater clear path, up to 15 feet, in locations with particularly high pedestrian volumes. Exceptions may be approved by DOT on a case-by-case basis 
  • Installations should be sited at locations that receive adequate flow
  • Locate treatments at least 7 feet from any below-ground vaults or basements to prevent water damage to these structures
  • Avoid locations in proximity to existing above-ground or subsurface utilities
  • Stormwater management areas should be sized in relation to the tributary drainage area to handle the volume of water entering into them; consult DEP’s latest Green Infrastructure Standards
  • Select soils that allow more rapid infiltration than typical horticultural soils and resist compaction while still supporting plant material
  • Direct runoff into planted areas via porous pavement, curb inlets, stormwater inlets with sub-surface pipes, or other methods approved by DEP
  • Utilize a pre-treatment system such as grates, a vegetative filter, or weirs to filter and collect sediment and floatables into a concentrated area; this system should be easy to clean out and will reduce the frequency of maintenance visits
  • Water entering the planted area should be detained and allowed to infiltrate into the soil; grade soil as a swale or depress the soil level below the inlet/outlet structures
  • Overflow must be allowed to flow to an existing catch basin; consider the use of graded outlet structures or overflow drains to direct excess water from larger storms into the sewer system
  • Consider permeable pavement wherever safe and feasible. See Permeable Interlocking Concrete Paver (PICP) and Precast Porous Concrete Panel in the Materials chapter

Plants

See Plant Finder

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