The overlay zoning districts of this chapter typically apply in combination with the underlying general use zoning districts to impose regulations and standards in addition to those required by the general use districts except where otherwise specified for a particular overlay district. The requirements of an overlay district shall apply whenever they are in conflict with and are more stringent than those in the general use district. Variances may not be granted from overlay district regulations unless specifically provided for in a particular overlay district. The following overlay districts are hereby created:
(A) Mixed Use Overlay;
(B) Conservation Residential Overlay;
(C) Thoroughfare Overlay;
(D) Airport Overlay;
(E) Watershed Protection Overlay; and
(F) Historic Preservation Overlay.