Home   /   Our People   /   Profiles   /   kcwong   /   Temporal and spatial variability of sea level and volume flux in the Murderkill Estuary

Temporal and spatial variability of sea level and volume flux in the Murderkill Estuary


Source: Estuarine Coastal and Shelf Science

The instantaneous sea level determined at two sites in the Murderkill Estuary, a tributary of Delaware Bay, results from the superposition of temporal variability operating over different time and spatial scales. Over the relatively short tidal time scales, the semidiurnal tides that represent the dominant tidal constituents in lower Delaware Bay show a modest increase in tidal amplitudes from the bay mouth (Lewes, Delaware), up to Bowers Beach (the mouth of the Murderkill Estuary). However, as the tides propagate into the Murderkill Estuary, the semidiurnal constituents undergo heavy attenuation, resulting in a 48% reduction in tidal amplitude from Bowers to Frederica (approximately the extent of saline intrusion). The diurnal tide, on the other hand, experiences only a 25% reduction in amplitude. The limited tidal asymmetry that is observed may be a result of interaction between flows in the tidal channel and the adjacent salt marsh. At longer time scales, the subtidal sea level experiences no attenuation. The Murderkill Estuary thus behaves like a low pass filter to preferentially damp out high frequency sea level forcing from lower Delaware Bay. The subtidal volume flux in the Murderkill is highly coherent with the time rate of change of sea level, indicating that the Murderkill basically co-oscillates with Delaware Bay in a standing wave fashion over the subtidal time scale. This remote coupling controls more than 90% of the variance in subtidal sea level in the estuary. The surface slopes in the lower bay and the Murderkill Estuary are closely correlated with winds along the orientation of the two waterways, consistent with the effect of local wind on subtidal sea level.

Learn more


CEOE School & Departments

School of Marine Science & Policy

Advancing the understanding, stewardship, and conservation of estuarine, coastal, and ocean environments.

Learn More
Department of Geological Sciences

Discovering how geological processes have operated over various time scales to create and influence the planet’s surface environments.

Learn More
Department of Geography

Investigating the interactions between people and the environment and the processes that explain the location of human and natural phenomena.

Learn More

College of Earth, Ocean, and Environment • 111 Robinson Hall • Newark, DE 19716 • USA
Phone: 302-831-2841 • E-mail: ceoe-info@udel.edu

Back to Top