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More Information: Topography in the SNAD

Updated: May 5, 2021

This overview of SNAD regulations is provided for informational purposes only—the actual regulations are much more complex than this overview. Contact the Bronx Office of City Planning, at 718-220-8500, with your specific project plans and a description of your property, to ensure that you comply with all zoning requirements. City Planning will guide you through the approval and permitting process.


Topography (including steep slopes)


Modifications to a slope can affect storm water and groundwater drainage patterns, soil conditions, and vegetation health. In the SNAD, lots are characterized as:

  • Tier I - average slopes of < 10 %

  • Tier II - average slopes of 10 % or greater (includes "steep slopes")

  • steep slopes - slopes of 25 % or greater


Maximum Lot Coverage Lot Coverage is the portion of a zoning lot which, when viewed from above, is covered by a building or portion of a building. Slope Zoning District Permitted Maximum Lot Coverage steep slope R1, R2, R3 12.5 %

steep slope R4 20.0 %

10 - 14.9 % R1 - R4 varies from 22.5 to 36 %

15 - 19.9 % R1 - R4 varies from 20.0 to 32 %

20 - 24.9 % R1 - R4 varies from 17.5 to 28 %

Topography Category Grading Regulation Zoning Regulation

Projects that do not require Review by Department of City Planning Section 105-021, b

a building permit, such as required for changes to topography

some swimming pools, of more than two feet

garden sheds, or fences

Tier I Sites: Authorization from the City Planning Section 105-421

Projects that require a Commission required for any

building permit modification of existing topography.

Tier II sites: Authorization from the City Planning

Projects that require a Commission or any grading beyond 15 feet

building permit of the location of a building foundation

(Exception: driveways and private roads)

Grading within 15 feet of a foundation Section 105-34

Grading within 15 feet of a foundation

slopes, compaction of fill, retaining walls,

and other grading elements

Driveways and private roads Section 105-35

 

Topsoil is protected from erosion during construction:

"Any exposed earth shall have straw, jute matting , or geotextiles placed on it within two days of exposure and be seeded with annual rye grass during construction." (Section 105-36, (f))" "A development on a Tier II site, that needs an authorization, must inst


all one of the following erosion and sedimentation control measures: benches and berms, diversion channels, debris or sediment basins, retention ponds, or grassed waterways or outlets. (Sect. 105 -37)"




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