What is an impervious surface?

An impervious surface refers to any surface that water cannot soak into, such as asphalt (streets), concrete (sidewalks), highly compacted crushed stone and gravel, and rooftops.  When water cannot soak into the ground, it either sits in one place or moves along to a place where it can soak into the ground or be collected.  As it moves along these hard surfaces it gathers pollutants like trash, oil, brake dust, fertilizer, salt, and pet waste.  

Approximately 25% of Susquehanna Township is covered in impervious surface.