Spring High Tides and Inundation Risk at Four Northeastern Coastal National Parks

This project analyzed spring high tides by using the tidal datum mean high water spring (MHWS) and determined inundation risk at four northeastern coastal national parks. We created two tools in the statistical program R, to find MHWS. The first compares elevations of the desired location to a control station. The second and more accurate tool finds and averages all the spring high tides. Record length (between 3-9 months) for various parts of the year at three stations was tested to determine how long of a record is needed to produce an accurate MHWS value. For six months of record length, 87% of the MHWS values had an error of 10 cm or less when compared to the MHWS value found over an entire tidal epoch. The ratio of MHWS to mean high water (MHW) at all the locations except Buntings Bridge at Assateague Island National Seashore had similar ratios. Buntings Bridge’s ratio was smaller, approximately half the size of the other locations including other microtidal sites. The inundation risk due to sea level rise (SLR) for MHWS was then compared to that of MHW to see if there was a difference between the datums under scenarios of 60 cm, 1 m, and 2 m of SLR. Buntings Bridge was the only location where the land was inundated under MHWS but not MHW; this occurred for SLR of 60 cm. SLR trends in MHWS and MHW were compared by looking at long term annual averages.