York River Physical Oceanography and Sediment Transport

Abstract

The York River is a partially-mixed, microtidal estuary with tidal currents in the mid- to upper estuary approaching 1 m/s. The upper York near West Point is generally less stratified than the lower York near Gloucester Point because of the shallower depths and stronger currents found upstream. Fluctuations in salinity stratification in the York River at tidal, fortnightly and seasonal time-scales are associated with tidal straining, the spring-neap cycle, and variations in freshwater discharge, respectively. Estuarine circulation in the York River, which averages ~5 to 7 cm/s, is often modulated by moderate winds. Waves are usually insignificant, although occasional severe storms have a major impact. The York River channel bed is predominantly mud, while the shoals tend to be sandier, and the mid- to upper York is marked by seasonally persistent regions of high turbidity. Fine sediment is trapped in high turbidity regions in response to tidal asymmetries and local variations in stratification and estuarine circulation. More work is needed to better understand the linkages between physical oceanography, sediment transport and turbidity in the York River system, especially during high-energy events and in response to ongoing climate change.