Water and Suspended-Sediment Flux Measurements at the Golden Gate, 2016-2017

Sediment is an important resource for San Francisco Bay (SFB), in the context of restoration projects, dredging operations, ecosystem health, and contaminant transport and fate. Understanding the transport and fate of sediment in SFB is important to ecosystem researchers and managers. Previous studies have shown that sediment exchange at the estuary-ocean boundary of SFB (Golden Gate inlet) is the most poorly understood element of the SFB sediment budget, owing to logistical challenges that inhibit routine field observations, and the fact that net flux is a small fraction of the instantaneous peak values experienced on a daily basis. Improved understanding of sediment exchange at the estuary-ocean boundary of SFB is essential to updating SFB-wide sediment budgets, which account for sources, sinks, and storage of sediment (and sediment-associated contaminants).

In this study, field observations of water and suspended-sediment fluxes at the Golden Gate were made over one ebb tide and one flood tide on three occasions:

1) 21-22 March 2016, following a large storm event that triggered the first flow into Yolo Bypass flood control structure since 2011

2) 23 June of 2016, during a period of low freshwater inflow;

3) 27-28 February 2017, following several large storms of the wettest winter in northern California in recorded history.