Capurso, William D. Simonson, Amy E. Noll, Michael L. Busciolano, Ronald Finkelstein, Jason S. 20230331 Tabular comma delimited, ESRI shapefile Denver, CO U.S. Geological Survey https://doi.org/10.5066/P9OMBJPQ. This data release contains results of a high-water mark survey across the five boroughs of New York City following flash flooding caused by the remnants of Hurricane Ida, September 1, 2021. The survey was conducted between September 7 and November 23, 2021, and is based on observations of mud, debris, and seed lines left by the flooding. Real time and static GNSS surveying as well as available lidar data were used to determine high-water mark elevations at 83 locations. Additional data associated with Hurricane Ida flooding can be found in the USGS Flood Event Viewer, https://stn.wim.usgs.gov/fev/#2021Ida In response to Federal Emergency Management Agency (FEMA) Mission Assignment 4615DR-NY-DOI-USGS-01, data were obtained in direct support and for situational awareness of FEMA disaster operations for a high-water or flood event. 20210908 20211123 ground condition Complete None planned -74.156753 -73.7652393 40.894233 40.589173 USGS Thesaurus floods ISO 19115 Topic inlandWaters None high-water Hurricane Ida high-water marks USGS Metadata Identifier USGS:618975c8d34ec04fc9c5a049 New York New York none none William D Capurso New York Water Science Center Hydrologic Technician mailing and physical

2045 Route 112

Coram NY 11727 US 631-736-0783 wcapurso@usgs.gov Federal Emergency Management Agency, Region 2 High-water mark data were checked by an independent reviewer for errors and anomalies made during transposition from field medium to database. High-water mark data were checked by an independent reviewer for errors and anomalies made during transposition from field medium to database. Data set is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record for additional details. Techniques and Methods 11–D1 Level 2 Real-time Network Survey were adhered to. Methods of practice and guidelines for using survey-grade global navigation satellite systems (GNSS) to establish vertical datum in the United States Geological Survey: U.S. Geological Survey Techniques and Methods, book 11, chap. D1, 102 p. with appendixes, https://pubs.usgs.gov/tm/11d1/tm11-D1.pdf. Techniques and Methods 11–D1 Level 2 Real-time Network Survey were adhered to. Methods of practice and guidelines for using survey-grade global navigation satellite systems (GNSS) to establish vertical datum in the United States Geological Survey: U.S. Geological Survey Techniques and Methods, book 11, chap. D1, 102 p. with appendixes, https://pubs.usgs.gov/tm/11d1/tm11-D1.pdf. U.S. Geological Survey 2023 tabular digital data Reston, VA U.S. Geological Survey https://stn.wim.usgs.gov/fev/ Digital 20210908 20211123 ground condition USGS FEV Source information used in support of the development of the data set. High-water mark data were downloaded from the USGS Flood Event Viewer (https://stn.wim.usgs.gov/fev/#2021Ida). The downloaded file is a composite of all high-water marks associated with Ida flooding collected by the USGS. Data were filtered to include only high-water marks collected in the five boroughs of New York City. An ESRI shapefile was generated using the latitude and longitude of the high-water mark data. 20230317 Point Entity point 159 0.0197454648 0.0259125304 Decimal seconds GCS WGS 1984 WGS 1984 6378137.0 298.257223563 North American Vertical Datum of 1988 0.1 US Survey Feet Explicit elevation coordinate included with horizontal coordinates FilteredHWMs_NewYork.csv: Comma-separated text file containing high-water marks in New York following the remnants of Hurricane Ida and associated flash flooding, September 2021. See STN_FilteredHWMs_data_dictionary_NY.csv for the definition of the column headings. FilteredHWMs_NewYork_CoverageFinal.zip: Zipped folder of shapefile containing high-water marks in New York following the remnants of Hurricane Ida and associated flash flooding, September 2021. See STN_FilteredHWMs_data_dictionary.csv for the definition of the column headings. Only the first 10 characters of the column headings of the shapefile will match the column headings of the data dictionary. STN_FilteredHWMs_data_dictionary_NY.csv: Comma-separated text file defining the column headings in FilteredHWMs New York.csv and FilteredHWMs_New York_CoverageFinal.shp. NOAA_AEP_3hr.png: Annual Exceedance Probabilities for the Highest 3-hour Rainfall Period, August 31, 2021 - Sep 2, 2021. The entity and attribute information was generated by the individual and/or agency identified as the originators of the dataset. Please review the rest of the metadata record for additional details and information. GS ScienceBase U.S. Geological Survey mailing and physical

Denver Federal Center, Building 810, Mail Stop 302

Denver Colorado 80225 United States 888-275-8747 sciencebase@usgs.gov Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. The USGS or the U.S. Government shall not be held liable for improper or incorrect use of the data described and/or contained herein. Users of the data are advised to read all metadata and associated documentation to understand appropriate use and data limitations. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Tabular comma delimited, ESRI shapefile None 2.0 https://www.sciencebase.gov/catalog/item/618975c8d34ec04fc9c5a049 None. No fees are applicable for obtaining the dataset. In addition to the included tabular high-water mark data in comma delimited format, an additional zip file is also included. This zip file contains the high-water mark data available in ESRI shapefile format. The user must have software capable of uncompressing the WinZip file and displaying the shapefile. In lieu of ArcView or ArcGIS, the user may utilize another GIS application package capable of importing the data using the coordinates found in the .CSV file. 20230331 William D Capurso New York Water Science Center Hydrologic Technician mailing and physical

2045 Route 112

Coram NY 11727 US 631-736-0783 wcapurso@usgs.gov Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998