The topographic features, including natural topography and topsoil, existing at the time of designation of a Special Natural Area District may be modified by the City Planning Commission, provided that the Commission finds that:

(a)        development, enlargement and site alteration is not feasible without such modification, or that the requested modification will permit a development, enlargement or site alteration that satisfies the purposes of this Chapter;

(b)        such modification, including any removal of topsoil, will not disturb the drainage pattern and soil conditions in the area;

(c)        such modification of topography has minimal impact on the existing topographic features of the surrounding area and blends harmoniously with it;

(d)        such modification is the least modification required to achieve the purpose for which it is granted; and

(e)        the development, enlargement or site alteration takes advantage of the natural characteristics of the site.

Where permits are required from a City agency, the Commission shall request a report from such agency, and the provisions of Section 105-93 (Inter-agency Coordination) shall apply.