Geospatial Datasets of Factors Influencing Pluvial Flood Potential in Long Island, New York and Near Coastal Areas Surrounding Long Island Sound in New York, Connecticut, and Rhode Island

This data release provides spatial digital data for factors that influence pluvial flood hazard potential, including closed depressions, curve number, drainage networks, topographic slope, average annual rainfall, 1-hr and 24-hour 100-year return period rainfall accumulation, and locations of recorded floods. In addition, these flood influencing factors are summarized to a common 900-meter by 900-meter polygrid and a pluvial flood hazard rank calculated for each grid cell according to methods described in Welk and others (2025). Two sets of flood hazard ranks are provided: one based on expert judgment using the Analytic Hierarchy Process (AHP), and another derived from iterative ensemble smoothing, in which AHP matrix values were varied and calibrated against a dataset of recorded flood locations. A pairwise comparison matrix is included to document the expert-based weighting process. More details are available in Welk and others (2025).