TY - JOUR
T1 - Effect of tides on solute flushing from a strait
T2 - Imaging flow and transport in the east river with SF6
AU - Caplow, Theodore
AU - Schlosser, Peter
AU - Ho, David T.
AU - Enriquez, Rica C.
PY - 2004/9/1
Y1 - 2004/9/1
N2 - In June 2003, two injections of ∼3.9 mol of sulfur hexafluoride (SF6) were made 8 days apart in the East River, a 25 km tidal strait, to observe solute mixing and dissipation. The first injection occurred at slack before flood, and the second at slack before ebb (flood = northward flow). Tidally synchronized surveys of the SF6 tracer patch, supplemented by vertical profiles, were conducted by boat for 6 and 4 days following the flood and ebb injections, respectively. Residence times for the tracer-tagged water mass in the East River were estimated to be 3.3 ± 0.7 days and 1.7 ± 0.5 days for the flood and ebb injections, respectively, after correcting SF6 inventories for losses of SF6 from the water column by air-water gas exchange. The data indicate that the majority of East River solutes are transported to New York Harbor and that tidal mixing dominates subtidal circulation with respect to solute transport. Surveys of the adjacent lower Hudson River revealed a northward-moving, intermediate layer of East River water. Our results suggest that tidal phasing of contaminant discharges in the East River could reduce environmental impacts, by increasing flushing rates and directing a greater fraction of material away from Long Island Sound.
AB - In June 2003, two injections of ∼3.9 mol of sulfur hexafluoride (SF6) were made 8 days apart in the East River, a 25 km tidal strait, to observe solute mixing and dissipation. The first injection occurred at slack before flood, and the second at slack before ebb (flood = northward flow). Tidally synchronized surveys of the SF6 tracer patch, supplemented by vertical profiles, were conducted by boat for 6 and 4 days following the flood and ebb injections, respectively. Residence times for the tracer-tagged water mass in the East River were estimated to be 3.3 ± 0.7 days and 1.7 ± 0.5 days for the flood and ebb injections, respectively, after correcting SF6 inventories for losses of SF6 from the water column by air-water gas exchange. The data indicate that the majority of East River solutes are transported to New York Harbor and that tidal mixing dominates subtidal circulation with respect to solute transport. Surveys of the adjacent lower Hudson River revealed a northward-moving, intermediate layer of East River water. Our results suggest that tidal phasing of contaminant discharges in the East River could reduce environmental impacts, by increasing flushing rates and directing a greater fraction of material away from Long Island Sound.
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U2 - 10.1021/es035248d
DO - 10.1021/es035248d
M3 - Article
C2 - 15461164
AN - SCOPUS:4444228205
SN - 0013-936X
VL - 38
SP - 4562
EP - 4571
JO - Environmental Science and Technology
JF - Environmental Science and Technology
IS - 17
ER -