Development area. The minimum development area required
to qualify for a PDD shall be 25 contiguous acres of land in the case
of a residential or mixed-use PDD, and 10 contiguous acres of land
in the case of a commercial or industrial PDD. The calculation of
such land area shall not include existing streets, easements, parks,
or otherwise dedicated land or acreage, or lands undevelopable by
reasons of topography, drainage, occurrence of wetlands, periodic
inundation by floodwaters, or adverse subsoil conditions.