Impact of Historical Channel Deepening on Tidal Hydraulics in the Delaware Estuary

Abstract

AbstractAnthropogenic modifications of estuarine morphology such as navigational channels have changed tidal dynamics in many estuaries. The implications of deepening may include shifts in tidal range, sediment transport, pollutant dispersal, and changes in flood risk, among others. Here, we use a numerical model to study how channel deepening has altered tidal elevation, currents, and energy fluxes in the Delaware, a convergent estuary on the east coast of the United States. Historical (1848) and modern (2014) depth soundings were digitized and gridded for a numerical model of the estuary. Numerical experiments indicate a doubling in tidal range, shifts in the arrival time of high water, and changes in elevation‐velocity phase. A historical increase in the upstream conveyance and transmission of energy is consistent with bigger amplitudes, swifter currents, and more progressive wave dynamics in the navigational channel. Changes in local topography were key in the modulation of tidal energy transmission upstream, especially in the tidal river.