The Hydrography at the Mouth of Delaware Bay: Tidally Averaged Distribution and Intratidal Variability

On 14 June 1990, hydrographic observations were conducted across the mouth of Delaware Bay over a semi-diurnal tidal cycle. CTD observations were repeatedly conducted at 10 stations across the bay mouth in order to resolve the tidal variability. The tidally averaged salinity distribution across the bay mouth shows significant lateral variability. Relatively high-salinity (and cool) water resides in the deep channel and domes towards the surface in the central portion of the bay mouth to the right of the channel. This high-salinity water separates two branches of low-salinity (and warm) water, one along the Delaware (left) shore and the other along the New Jersey (right) shore. As for the intratidal variability, the data suggest that the temporal distribution of salinity depends strongly on the position across the bay mouth. The data also indicate that sharp frontal boundaries which separate the warm/brackish estuarine water from the cool/saline shelf water exist throughout the tidal cycle. Across the frontal boundary the salinity may vary by up to 3 and the temperature may vary by 2 °C over a distance of 150 m.