scholarly journals Description of beds exposed at Fort Funston, Golden Gate National Recreation Area, northwestern San Francisco Peninsula, California

1982 ◽  
Author(s):  
R.E. Hunter ◽  
H.E. Clifton
Author(s):  
Maureen A. Downing-Kunz ◽  
Paul A. Work ◽  
David H. Schoellhamer

AbstractSuspended-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.


2016 ◽  
Vol 6 (1) ◽  
pp. 130-136
Author(s):  
Brock Winstead

Treasure Island in San Francisco Bay was created to host the Golden Gate International Exposition, a World’s Fair, in 1939-40. The fair was an expression of an idealized order of both design and international relations. Neither survived much longer than the fair itself. The author considers the creation and re-creation of Treasure Island and the problem of building for an uncertain, ultimately unknowable future. This article is a critical appreciation of Andrew Shanken’s Into the Void Pacific, a design history of the fair.


1949 ◽  
Vol 81 (6) ◽  
pp. 153-158 ◽  
Author(s):  
Stanley F. Bailey

One of the few Canadian entomologists to study thrips was R. C. Treherne who was one of the group of workers to investigate the pear thrips when it first became an economic pest in North America. In the course of his work he collected and studied thysanoptera. His collection, supplemented by exchanges with other workers, formed the basis for the material now in the Canadian National Collection at Ottawa. The writer is indebted to curators of this collection and particularly T. N. Freeman, for the generous loan of valuable specimens for study, particularly the types of Treherne. The Moulton collection is now deposited at the San Francisco Academy of Science, Golden Gate Park, San Francisco, California. We also wish to thank Dr. E. S. Ross, curator, for the opportunity of studying the types of Taeniothrips tahoei Moulton, Tae. pingreei Moulton, Tae. aureus Moulton, and Frankliniella californica Moulton.


1979 ◽  
Author(s):  
S. M. Kowleski ◽  
C. D. Harrington

This paper describes the planning, developmental, equipment selection and operational problem phases of the high-speed ferry system presently being operated on San Francisco Bay by the Golden Gate Bridge, Highway and Transportation District. The reasons for the selection of the vessel propulsion package consisting of gas turbine engines and waterjet pumps are discussed in some detail. Most importantly, the paper covers the problems experienced to date with this equipment in continuous marine operation.


Sign in / Sign up

Export Citation Format

Share Document