Sea-level rise and local tidal range changes in coastal embayments: An added complexity in developing reliable sea-level index points

Abstract

This paper re-evaluates the late Holocene sea-level reconstructions from Delaware Bay and assesses the possible effect of tidal range changes over the last 4000 years. Previous work suggested that the differences found between the northern and southern areas of the Delaware Bay (USA) could be explained by isostatic rebound. However, our results derived from tidal modeling suggest that at least 25% of this difference could be explained by changes in the tidal range due to amplification or attenuation of tidal waves over shallower bathymetry. Furthermore, indications of large changes of the tidal range over short distances might suggest that integration of sea-level index points from different areas should be performed with caution. New sea-level trend estimates have been calculated at 1.17±0.2 mm yr-1 in the southern area, and 1.55±0.2 mm yr-1 in the north