File #: Int 1244-2025    Version: * Name: Creation of a groundwater flood risk area map.
Type: Introduction Status: Committee
Committee: Committee on Environmental Protection, Resiliency and Waterfronts
On agenda: 4/10/2025
Enactment date: Law number:
Title: A Local Law to amend the administrative code of the City of New York and the New York city building code, in relation to the creation of a groundwater flood risk area map
Sponsors: Nantasha M. Williams, Selvena N. Brooks-Powers, Mercedes Narcisse, Carlina Rivera , Justin L. Brannan, Julie Menin, Chi A. Ossé, Farah N. Louis, Amanda Farías, Vickie Paladino
Council Member Sponsors: 10
Summary: This bill would require the Department of Environmental Protection (“DEP”) to determine areas at risk of groundwater flooding in New York City and add such areas to the flood hazard area map. The bill would also require DEP to consider the need to update the groundwater flood risk area when new data related to groundwater levels in New York City are available. The bill would also amend Appendix U of the Building Code to prohibit cellar or basement accessory dwelling units in groundwater flood risk areas 90 days after DEP updates such map.
Indexes: Agency Rule-making Required
Attachments: 1. Summary of Int. No. 1244, 2. Int. No. 1244, 3. April 10, 2025 - Stated Meeting Agenda

Int. No. 1244

 

By Council Members Williams, Brooks-Powers, Narcisse, Rivera, Brannan, Menin, Ossé, Louis, Farías and Paladino

 

A Local Law to amend the administrative code of the City of New York and the New York city building code, in relation to the creation of a groundwater flood risk area map

 

Be it enacted by the Council as follows:

 

Section 1. Subdivision a of section 24-809 of the administrative code of the city of New York is amended by adding a definition of “groundwater flood risk area” in alphabetical order to read as follows:

Groundwater flood risk area. The term “groundwater flood risk area” means an area designated on a map promulgated by the department that represents locations in the city where the depth to the water table is less than 10 feet, incorporating the impacts of the projected 2050 sea level rise on groundwater table depths as projected by the United States geological survey.

§ 2. Paragraphs 2 and 3 of subdivision b of section 24-809 of the administrative code of the city of New York, as added by local law number 124 for the year 2024, are amended to read as follows:

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 the groundwater flood risk area, and 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] subdivision, 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.

                     (d) Within 1 year of the completion of a citywide groundwater table survey conducted by the department and the United States geological survey, 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 groundwater flood risk area adopted pursuant to subparagraph (a) of this paragraph should be updated based on such survey, and any other data such agencies determine to be reasonable. The department shall adopt any such updated groundwater flood risk area by rule and post on the city’s website an updated flood risk area map showing such updated groundwater flood 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] locations 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 and groundwater 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] areas can clearly be determined; and

(c) include any relevant information on the 10-year rainfall flood risk area [and], coastal flood risk area, and groundwater flood risk area, such as general elevation or topography indicators, to the extent available to the department.

§ 3. Section U202.2 of appendix U of the New York city building code is amended by adding a new definition of “groundwater flood risk area” in alphabetical order to read as follows:

GROUNDWATER FLOOD RISK AREA. Shall have the same definition as such term is defined in Section 24-809 of the Administrative Code.

                     § 4. Section U202.3 of appendix U of the New York city building code, as added by local law number 127 for the year 2024, is amended to read as follows:

U202.3 Prohibited locations. An ADU shall not be permitted in a basement or cellar of a building in the following locations, except as otherwise provided pursuant to the New York City Zoning Resolution:

1. Within the special flood hazard area in accordance with Appendix G.

2. Within the 10-year rainfall flood risk area.

3. Within the coastal flood risk area.

4. Within the groundwater flood risk area.

U202.3.1 Identification of flood hazard areas. Where an ADU is permitted in accordance with Section U202.3, the construction documents for the ADU shall include a statement to certify that the premises are not located in any one of the following flood hazard areas:

1. Special flood hazard area, in accordance with Section G201.

1.1 Coastal A-zone.

1.2 Coastal high-hazard area.

1.3 A-zone.

2. 10-year rainfall flood risk area.

3. Coastal flood risk area.

4. Groundwater flood risk area.

Each such statement shall be accompanied with the applicable flood area map.

                     § 5. Section U203.7 of appendix U of the New York city building code, as added by local law number 127 for the year 2024, is amended to read as follows:

U203.7 Flood mitigation. The department may promulgate rules relating to requirements for flood mitigation applicable to an ADU in the groundwater flood risk area, coastal flood risk area, or 10-year rainfall flood risk area.

§ 6. This local law takes effect immediately, except that sections three, four, and five of this local law take effect 90 days after the department of environmental protection adopts the rule updating the flood risk area map showing the groundwater flood risk area, as required by section one of this local law.

NNB

LS #18524

4/3/2025 10:45 AM