Suspended-sediment flux at the ocean boundary of the San Francisco Estuary—the Golden Gate—was measured over a tidal cycle following peak watershed runoff from storms to the estuary in two successive years to investigate sediment transport through the estuary. Observations were repeated during low-runoff conditions, for a total of three field campaigns. Boat-based measurements of velocity and acoustic backscatter were used to calculate water and suspended-sediment flux at a location 1 km landward of the Golden Gate. Suspended-sediment concentration (SSC) and salinity data from up-estuary sensors were used to track watershed-sourced sediment plumes through the estuary. Estimates of suspended-sediment load from the watershed and net suspended-sediment flux for one up-estuary subembayment were used to infer in-estuary trapping of sediment. For both post-storm field campaigns, observations at the ocean boundary were conducted on the receding limb of the watershed hydrograph. At the ocean boundary, peak instantaneous suspended-sediment flux was tidally asymmetric and was greater on flood tides than on ebb tides for all three field campaigns, due to higher average SSC in the cross-section on flood tides. Shear-induced sediment resuspension was greater on flood tides and suggests the presence of an erodible pool outside the estuary. The storms in 2016 led to less export of discharge and sediment from the watershed and greater sediment trapping within one up-estuary subembayment compared to that observed in 2017. Results suggest that substantial trapping of watershed sediments occurred during both storm events, likely due to the formation of estuarine turbidity maxima (ETM) at different locations in the estuary. ETM locations were forced nearer the ocean boundary in 2017. Additional measurements and modeling are required to quantify the long-term sediment flux at the Golden Gate.

在连续两年中，从暴风雨到河口的分水岭径流达到峰值之后，在一个潮汐周期中测量了旧金山河口海洋边界（金门）的悬浮泥沙通量，以调查通过河口的沉积物。在低径流条件下重复观察，总共进行了三个野外活动。基于船速和声学反向散射的测量值用于计算金门口向岸1公里处的水和悬浮泥沙通量。来自上河口传感器的悬浮沉积物浓度（SSC）和盐度数据被用来跟踪流经河口的流域沉积物羽流。利用分水岭和一个上河口子河堤的净悬浮泥沙通量估算悬浮泥沙负荷，以推断河口的泥沙淤积。对于两次暴风雨后的野战，都在流域水文图的后退边上进行了海洋边界的观测。在海洋边界处，由于三个区域的潮汐平均SSC较高，因此瞬时峰值悬浮悬浮物通量在潮汐上是不对称的，并且在所有三个野战活动中，潮汐潮汐比潮汐潮汐要大。剪切引起的泥沙在潮汐中的重悬作用更大，表明河口外存在易蚀池。与2017年观察到的情况相比，2016年的风暴导致流域的排放物和沉积物的出口量减少，并且一个上河口子河道中的沉积物捕获量增加。结果表明，在两次风暴事件中都发生了对流域沉积物的大量捕获，可能是由于在河口的不同位置形成了最大的河口浊度（ETM）。ETM位置在2017年被迫靠近海洋边界。需要额外的测量和建模来量化金门大桥的长期沉积物通量。