Scope. This enactment of Downtown District Site Design Guidelines and Downtown Design Overlay District boundaries shall not repeal, abrogate, annul, impair, interfere or supercede any existing zoning ordinances, permits, easements, covenants, or agreements between parties or permits previously issued; provided, however, that where the Downtown District Site Design Guidelines in any way impose standards not required by other existing zoning ordinances, permits, easements, covenants or agreements, the provisions of the Downtown District Site Design Guidelines shall be used to supplement them.