overlay zone means a mapped overlay superimposed on one or more established zoning areas which may be used to impose supplemental restrictions on uses in these areas or permit uses otherwise disallowed;
Mixing zone means a limited area of a surface water body or aquifer where initial dilution of a discharge takes place and where certain water quality standards may be exceeded.
Buffer Zone means an area designated to be left along roads or other features in which there will be no cutting.
Excavation zone means the volume containing the tank system and backfill material bounded by the ground surface, walls, and floor of the pit and trenches into which the UST system is placed at the time of installation.
Seismic impact zone means an area with a 10% or greater probability that the maximum horizontal acceleration in lithified earth material, expressed as a percentage of the earth's gravitational pull (g), will exceed 0.10g in 250 years.