D. No other feasible alternative to a variance is available to the petitioner;

E. The granting of a variance will not unreasonably adversely affect the natural environment; and

F. The property is not located in whole or in part within shoreland areas as described in Title 38, section 435.

As used in this subsection, "dimensional standards" means and is limited to ordinance provisions relating to lot area, lot coverage, frontage and setback requirements.

As used in this subsection, "practical difficulty" means that the strict application of the ordinance to the property precludes the ability of the petitioner to pursue a use permitted in the zoning district in which the property is located and results in significant economic injury to the petitioner.

Under its home rule authority, a municipality may, in an ordinance adopted pursuant to this subsection, adopt additional limitations on the granting of a variance from the dimensional standards of a zoning ordinance. A zoning ordinance also may explicitly delegate to the municipal reviewing authority the ability to approve development proposals that do not meet the dimensional standards otherwise required, in order to promote cluster development, to accommodate lots with insufficient frontage or to provide for reduced setbacks for lots or buildings made nonconforming by municipal zoning.__As long as the development falls within the parameters of such an ordinance, the approval is not considered the granting of a variance.__This delegation of authority does not authorize the reduction of dimensional standards required under the mandatory shoreland zoning laws, Title 38, chapter 3, subchapter 1, article 2-B.