In Community District 6 in the Borough of Manhattan, for buildings developed or enlarged with towers in R10 Districts located east of First Avenue and north of East 51st Street, the tower provisions of paragraph (a) of Section 23-65 (Tower Regulations) shall be modified to require that the tower-on-a-base provisions of Section 23-651 apply to all buildings where more than 25 percent of the total floor area of the building is allocated to residential uses. However, for zoning lots with narrow street frontages, such provisions shall be modified in accordance with the provisions of this Section.

(a)        Tower modifications

The tower regulations of paragraph (a) of Section 23-651 shall be modified as follows:

(1)        For buildings that do not meet the location criteria of paragraph (a)(2) of Section 23-65, the provisions of paragraph (a)(3) of Section 23-651 shall be modified to require at least 45 percent of the total floor area permitted on the zoning lot to be located in stories located either partially or entirely below a height of 150 feet. In addition, when the lot coverage of the tower is less than 40 percent, the required 45 percent of the total floor area distribution, within a height of 150 feet, shall be increased in accordance with the following requirement:

(2)        For buildings that do not meet the location criteria of paragraph (a)(2) of Section 23-65, the tower setback provisions of paragraph (a)(4) of Section 23-651 shall be modified to permit such required setback along a narrow street to be reduced by one foot for every foot that the street wall is located beyond the street line. However, in no event shall a setback of less than seven feet in depth be provided.

(3)        The tower location restrictions of paragraph (a)(5) of Section 23-651 shall not apply. In lieu thereof, towers shall be permitted on a narrow street beyond 100 feet of its intersection with a wide street.

(4)        For the purposes of determining the permitted tower coverage and the required minimum distance between buildings or portions thereof on zoning lots with both narrow street and wide street frontage, that portion of a zoning lot located either within 125 feet from the wide street frontage along the short dimension of a block or within 100 feet from the wide street frontage along the long dimension of a block, shall be treated as a separate zoning lot from that portion beyond, with frontage along a narrow street.  

(b)        Building base modifications

The building base regulations of paragraph (b) of Section 23-651 shall be modified as follows:

(1)        For buildings, or portions thereof, fronting on a narrow street beyond 125 feet of its intersection with a wide street, the street wall location provisions of paragraph (b)(1)(ii) of Section 23-651 shall be modified to require that at least 70 percent of the aggregate width of street walls in the building base be located within eight feet of the street line.

(2)        For buildings, or portions thereof, fronting on a narrow street beyond 100 feet of its intersection with a wide street, the height of street wall provisions of paragraph (b)(2)(ii) of Section 23-651 shall be modified so that where the height of an adjacent building is between 60 feet and 85 feet, one of the three matching alternatives set forth in paragraphs (b)(2)(i)(a) through (b)(2)(i)(c) shall be applied.

(3)        The dormer provisions of paragraph (b)(3) of Section 23-651 shall be modified to permit dormers on narrow streets beyond 70 feet of its intersection with a wide street.