For all developments, enlargements or site alterations on Tier I sites, the following materials shall be submitted to the Department of Buildings. However, the submission requirements set forth herein shall not apply to an enlargement of an existing residential building, provided that such enlargement does not increase the lot coverage of said building. No building permit shall be issued until the Department of Buildings determines that the requirements of the Special Hillsides Preservation District have been met.

(a)        A survey map prepared by a licensed surveyor showing topography at two-foot contour intervals and indicating the existing slope of the land, as it occurs, in categories of 10–14 percent, 15–19 percent, 20–24 percent, 25 percent and greater; the location of existing buildings or other structures, patios, decks, swimming pools, walkways, driveways and private roads, including sidewalks and other impervious surfaces; and the location, caliper and species of all trees of six-inch caliper or more on the zoning lot and in the sidewalk area of the adjacent streets.

(b)        A site plan prepared by a registered architect or professional engineer indicating the location of all existing buildings or other structures; the location of all proposed buildings or other structures; the location of existing and proposed patios, decks, swimming pools, walkways, driveways and private roads, including sidewalks and other impervious surfaces; the location of any steep slopes, steep slope buffer areas and the staging area; and the location, caliper and species of all trees of six-inch caliper or more on the zoning lot and in the sidewalk area of the adjacent streets. The site plan shall identify those trees proposed to be removed and those trees proposed to be preserved, indicating, for the latter, the critical root zone.

(c)        A tree-planting plan, prepared by a registered landscape architect, indicating the location and species of all new plantings, and indicating the location of and the critical root zone around all trees proposed for preservation.