§ 24-809 Flood risk area map.
AC § 24-809
a. Definitions. As used in this section, the following terms have the following meanings: 10-year rainfall flood risk area. The term “10-year rainfall flood risk area” means an area designated on a map promulgated by the department of environmental protection that represents locations in the city where there is a 10 percent chance or greater of rainfall-induced flooding in any year, incorporating the impacts of the projected 2050 sea level rise on sewer outfalls and storm drains as projected by the New York city panel on climate change. Coastal flood risk area. The term “coastal flood risk area” means an area designated on a map promulgated by the department of environmental protection that represents locations in the city where there is a 1 percent chance or greater of flooding in any year, incorporating the impacts of sea level rise as projected for the year 2080 by the New York city panel on climate change, provided that if such panel provides projections for baseline years later in time to 2080 then such baseline years may be adopted by rule for the purposes of this definition. In initially determining such area, the department, in consultation with other relevant agencies as described in subdivision b of this section, shall consider the federal emergency management agency coastal flood mapping data that defines the current 100-year floodplain, and the best available data, as determined by the department and such agencies, including 90th percentile projections from the New York city panel on climate change and any other data determined to be reasonable, that reflects the 1 percent chance or greater of flooding in any year. Department. The term “department” means the department of environmental protection. b. Flood risk area maps.
1.The department, in consultation with the department of buildings, the office of long-term planning and sustainability, and other relevant agencies shall promulgate a rule to adopt an interim flood risk area map, showing the 10-year rainfall risk area and the coastal flood risk area, and post a map, as described in this subdivision, of such areas on the city’s website. No less than 1 year after the map required by paragraph 2 of this subdivision has first been adopted, the interim map required by this paragraph shall no longer be required to be posted.
2.
(a)No later than January 1, 2028, the department, in consultation with the department of buildings, the office of long-term planning and sustainability, and other relevant agencies shall adopt by rule and post on the city’s website, an updated flood risk area map, showing an updated 10-year rainfall risk area to replace such risk area adopted pursuant to paragraph 1 of this subdivision.
(b)Within 1 year of the issuance of new effective flood insurance rate maps for the city of New York by the federal emergency management agency, the department, in consultation with the department of buildings, the office of long-term planning and sustainability, and other relevant agencies, may consider whether the coastal flood risk area should be updated to replace the interim coastal flood risk area established pursuant to paragraph 1 of this section, based on projections of the New York city panel on climate change and any other data such agencies determine to be reasonable. The department shall adopt any such updated coastal flood risk area by rule and post such updated map with the flood risk area map adopted in accordance with this paragraph.
(c)Within 1 year of the issuance of new projections by the New York city panel on climate change, pursuant to subdivision 2 of section 3-122, the department may, in consultation with the department of buildings, the office of long-term planning and sustainability, and other relevant agencies, consider whether the 10-year rainfall risk area adopted pursuant to subparagraph (a) of this paragraph should be updated based on such projections, and any other data such agencies determine to be reasonable. The department shall adopt any such updated 10-year rainfall risk area by rule and post on the city’s website an updated flood risk area map showing such updated 10-year rainfall risk area to replace such risk area adopted pursuant to subparagraph (a) of this paragraph.
3.Any such updated maps, and to the extent practicable such interim maps, shall: (a) indicate the location of the special flood hazard area and the flood hazard area, as such terms are defined in section 202 of the New York city building code and as adopted pursuant to section G102.2 of appendix G of the New York city building code, provided that inclusion of such areas in such map shall not require adoption by rule pursuant to this subdivision to determine their boundaries; (b) represent the 10-year rainfall flood risk area using bounds at either the block or individual property level, such that the inclusion or exclusion of a property from such area can clearly be determined; and (c) include any relevant information on the 10-year rainfall flood risk area and coastal flood risk area, such as general elevation or topography indicators, to the extent available to the department. (L.L. 2024/124, 12/18/2024, eff. 6/16/2025)
