This line represents the approximate MLLW line for coastal Rhode Island. The line was derived from a seamless topographic/bathymetric (topobathy) dataset developed as part of the STORMTOOLS inundation modeling project. The primary source of the data were the USGS CoNED dataset (2016) for New England (1m spatial resolution). Prior to generating the MLLW line all topobathy values were converted from NAVD88 vertical to MLLW vertical using the NOAA VDatum tool. A description of the methods employed for the vertical datum conversion can be found in the NOAA Method Description Paper: Detailed Method for Mapping Sea Level Rise Inundation, January 2017, NOAA Office for Coastal Management.

Due to limitations with the source data, and the inherent difficulty in obtaining accurate elevation/depth values in the nearshore environment, these data should only be used as a general guide, and field visits may be needed to determine the validity of the information provided.