Description: The SMP Impervious Area feature class contains the impervious surface area delineation for the Northeast Ohio Regional Sewer District's stormwater service area. The impervious source may vary - ranging from Satellite Derived Impervious Area (from Quickbird Imagery) from 2007 to manually digitized impervious area using digital ortho images from 2008, 2011, 2013 and other sources.