For any development or enlargement on a zoning lot, or portion thereof, within C6-3A Districts or within Subareas A, C, F or G and over which the High Line passes or on a zoning lot adjacent to a zoning lot over which the High Line passes, a landscaped open area shall be provided in an amount equal to at least 20 percent of the lot area of the portion of the zoning lot that is within C6-3A Districts or within Subareas A, C, F or G, pursuant to the requirements of paragraphs (a) and (b) of this Section. Such open area shall be located directly adjacent to the High Line with its longest side adjacent to the High Line and shall be located at an elevation not to exceed a height of 3 feet, 6 inches above the level of the High Line bed adjacent to the zoning lot. At no point shall such open area be located within 50 feet of Tenth Avenue.

(a)        Open area requirements

All required open areas shall:

(1)        have no portion used as a driveway, vehicular access way or for parking, and shall be screened from off-street loading and service areas;

(2)        be landscaped with shrubs, vines, flowers, ground cover, trees, and/or plants in planters over a minimum of 25 percent of the required open area;

(3)        be maintained by the building owner who shall be responsible for the maintenance of the open area including, but not limited to, the repair of all amenities, litter control and the care and replacement of vegetation within the zoning lot;

(4)        have all mechanical equipment which is located at the same elevation as the open area, or within 15 feet of the level of the open area, screened and buffered with no intake or exhaust fans facing directly onto the required open area; and

(5)        for open area screening, required open areas may be screened from the public areas of the High Line by a wall, fence, or plantings extending not higher than eight feet above the average elevation of the open area. All screening materials must be substantially transparent. For the purposes of this Section, substantially transparent screening is defined as transparent, or non-opaque, in an evenly distributed fashion for at least 75 percent of its area. Chain link fences and razor wire shall not be permitted. Vegetated screening, such as shrubs, vines and other plantings, may be opaque if completely covered by vegetation, provided that any underlying surface is substantially transparent.

In addition, such screening material shall be maintained in good condition at all times, may be interrupted by normal entrances and/or exits, and shall have no signs hung or attached thereto, other than those permitted in Section 98-15.

(b)        Permitted obstructions

Only the following shall be permitted to obstruct a required open area:

(1)        any High Line access structure providing pedestrian access to the High Line by stairway or elevator;

(2)        the portions of buildings in which High Line Service Facilities are provided in accordance with paragraph (b)(4) of Appendix E;

(3)        those items listed in paragraph (a) of Section 37-726 (Permitted obstructions); and

(4)        open air cafes and kiosks, provided that open air cafes may occupy in the aggregate no more than 75 percent of such required open area.