Upwelling and estuary flushing1

Abstract

Salinity data collected during 1965–1969 in Grays Harbor, Washington, along with river discharge data, were used to determine the water and salt budgets of the inner harbor. The fluxes of water at the seaward end of the inner harbor, T o seaward at the surface and T i inward at depth, were calculated. T o was proportional to but larger than the river discharge throughout the year except for the months of August through October, when T o was related to T i and T i was driven by the influx of dense water into the harbor caused by upwelling along the coast. Thus the flushing rate of the inner harbor, as determined by its volume divided by T o , is much greater during late summer than previously suspected. The calculated rate of removal of material associated with the water in the inner harbor, based on a T o derived from river flow and the percentages of river and harbor water making up T o , is 19% per day, in agreement with a previous flushing study.