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Town of Clarence Residential Lot Grading and Drainage Plan Requirements

All Subdivision lot grading/drainage plans must be stamped by a licensed engineer and contain the following:

  • Elevations consistent with those shown on the approved subdivision grading plan. 
  • Elevations utilizing the same datum as those on the approved subdivision grading plan. 
  • Erosion control is required on all lots and must be shown on the plan. Silt sock or fence is required to limit offsite transport of sediment and associated sediment laden flows and to protect roads and any existing drainage systems, including any yard drains. 
  • Top of foundation wall, garage floor, adjacent grade(s) to the structure and basement floor elevations must be shown on the plan.
  • Road centerline elevation at the center of the lot must be shown on the plan. 
  • All rear yard drains with as-built rim and invert elevations must be shown on the plan.
  • Side yard and rear yard swales with percent slope and flow direction must be shown on the plan. 
  • Proposed grade elevations on property line adjacent to the proposed structure. 
  • Show all easements (drainage, sanitary sewer, etc.).
  • Driveway location and configuration with dimensions. 
  • Show all downspout and sump pump conductor lines. 
  • Any additional information as required by the Engineering Department. 

All Non-Subdivision lot grading/drainage plans must be stamped by a licensed engineer and contain the following:

  • Existing elevations utilizing USGS or NAVD 88’ datum (NAVD 88’ in and adjacent to floodplain/floodway).
  • Show and label floodplain with base flood elevation, floodway, NYSDEC wetlands and buffer areas, federal wetlands. 
  • Show all limits of stripping and grading and clearly label the land disturbance area on the plan. 
  • Erosion control is required on all lots and must be shown on the plan. Silt sock or fence is required to limit offsite transport of sediment and associated sediment laden flows and to protect any existing drainage systems. 
  • If one or more acre is disturbed, an Erosion & Sediment Control plan is required by a Qualified Professional per most recent NYSDEC General Permit for Construction Activity. SWPPP is required for the Lot.
  • Top of foundation wall, garage floor, adjacent grade(s) to the structure and basement floor elevations must be shown on the plan.
  • Road centerline elevation at the center of the lot must be shown on the plan. 
  • All drainage structures (including ditches and swales) rim and invert elevations must be shown on the plan.
  • Side yard swales with percent slope, grades and flow direction must be shown on the plan. 
  • Show all easements (sewer, drainage, etc.). 
  • Show downspout and sump pump conductor lines.
  • Any additional information as required by the Engineering Department

5-11-2020

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