Author(s): John C. Warner; David H. Schoellhamer; Jon R. Burau
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Abstract: Time series measurements of current velocity, depth, and suspended-solids concentra-tion (SSC) were used to determine suspended-solids fluxes (SSF) during the fall of 1995 at a site in central Honker Bay and at a site at the northern end of Spoonbill Creek. Significant increases in SSF occurred at both sites during periods of sustained winds directed along the axis of Honker Bay (westerly winds). The wind-induced sur-face shear stress increases SSF out of Honker Bay through Spoonbill Creek through the combination of two effects: (1) wind-wave resuspension of bed sediments elevates SSC within Honker Bay, and, at the same time, (2) wind shear raises the water level at the eastern end of Honker Bay relative to the Sacramento River, thereby creating a net barotropic pressure gradient across Spoonbill Creek that drives a residual advective SSF from Honker Bay through Spoonbill Creek into the Sacramento River. The resid-ual dispersive flux was also out of Honker Bay into the Sacramento River because the tidal excursion in Spoonbill Creek (approximately 4 to 6 km) is much longer than Spoonbill Creek (3 km). Therefore, high SSC water advected from Honker Bay into the S acramento River through Spoonbill Creek on the flood tide does not return on the following ebb tide, which creates the dispersive SSF. Diurnal inequality was greatest during neap tides and, during strong westerly winds, created a greater dispersive flux than observed during spring tides. The total SSF was always out of Honker Bay during the fall, suggesting that the relatively high metals and pesticides concentrations observed in the bottom sediments of Honker Bay are not caused by transport through Spoonbill Creek into Honker B ay during this time of year.
Year: 1997