Runoff The portion of rainfall or snowmelt that flows over impervious urban surfaces like sidewalks, roads, and driveways instead of soaking into the ground.
Unmanaged sidewalk runoff can cause substantial local erosion, overwhelm curbside gutters, and lead to standing water on private property. NYC properties are designed to channel runoff directly into municipal street gutters and catch basins. Property owners can optimize runoff management by ensuring their sidewalks are graded properly and by integrating porous materials, well-sized tree pits, or green spaces that capture and slow down water flow before it hits the street.
Frequently Asked Questions About Runoff
What is runoff?
The portion of rainfall or snowmelt that flows across paved surfaces rather than soaking into the ground.
What problems does unmanaged runoff cause?
Erosion beneath slabs, overwhelmed gutters, standing water and flooding of adjacent private property.
Where should sidewalk runoff go?
Into the street gutter and then to the catch basin, following the grades the sidewalk and curb were designed to create.
How can an owner manage it better?
By keeping the sidewalk correctly graded, directing downspouts appropriately, and using well-sized tree pits or permeable areas where allowed.