Sr-Nd isotopic analyses of sand-sized sediment from the San Francisco Bay coastal system

A diverse suite of geochemical tracers, including 87Sr/86Sr and 143Nd/144Nd isotope ratios, the rare earth elements (REEs), and select trace elements were used to determine sand-sized sediment provenance and transport pathways within the San Francisco Bay coastal system. This study complements a large interdisciplinary effort (Barnard et al., 2012) that seeks to better understand recent geomorphic change in a highly urbanized and dynamic estuarine-coastal setting. Sand-sized sediment provenance in this geologically complex system is important to estuarine resource managers and was assessed by examining the geographic distribution of this suite of geochemical tracers from the primary sources (fluvial and rock) throughout the bay, adjacent coast, and beaches. Due to their intrinsic geochemical nature, 143Nd/144Nd isotopic ratios provide the most resolved picture of where sediment in this system is likely sourced and how it moves through this estuarine system into the Pacific Ocean. For example, Nd isotopes confirm that the predominant source of sand-sized sediment to Suisun Bay, San Pablo Bay, and Central Bay is the Sierra Nevada Batholith via the Sacramento River, with lesser contributions from the Napa and San Joaquin Rivers. Isotopic ratios also reveal hot-spots of local sediment accumulation, such as the basalt and chert deposits around the Golden Gate Bridge and the high magnetite deposits of Ocean Beach. Sand-sized sediment that exits San Francisco Bay accumulates on the ebb-tidal delta and is in part conveyed southward by long-shore currents. Broadly, the geochemical tracers reveal a complex story of multiple sediment sources, dynamic intra-bay sediment mixing and reworking, and eventual dilution and transport by energetic marine processes. Combined geochemical results provide information on sediment movement into and through San Francisco Bay and further our understanding of how sustained anthropogenic activities which limit sediment inputs to the system (e.g., dike and dam construction) as well as those which directly remove sediments from within the Bay, such as aggregate mining and dredging, can have long-lasting effects.

Heavy mineral analyses of sediment samples from the San Francisco Bay coastal system

Heavy or high-specific gravity minerals make up a small but diagnostic component of sediment that is well suited for determining the provenance and distribution of sediment transported through estuarine and coastal systems worldwide. By this means, we see that surficial sand-sized sediment in the San Francisco Bay Coastal System comes primarily from the Sierra Nevada and associated terranes by way of the Sacramento and San Joaquin Rivers and is transported with little dilution through the San Francisco Bay and out the Golden Gate. Heavy minerals document a slight change from the strictly Sierran-Sacramento mineralogy at the confluence of the two rivers to a composition that includes minor amounts of chert and other Franciscan Complex components west of Carquinez Strait. Between Carquinez Strait and the San Francisco Bar, Sierran sediment is intermingled with Franciscan-modified Sierran sediment. The latter continues out the Gate and turns southward towards beaches of the San Francisco Peninsula. The Sierran sediment also fans out from the San Francisco Bar to merge with a Sierran province on the shelf in the Gulf of the Farallones. Beach-sand sized sediment from the Russian River is transported southward to Point Reyes where it spreads out to define a Franciscan sediment province on the shelf, but does not continue southward to contribute to the sediment in the Golden Gate area.

San Francisco Bay Area, California, Nautical Chart, 1877 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Entrance to San Francisco Bay, California, from a trigonometrical survey under the direction of A.D. Bache, Superintendent of the Survey of the Coast of the United States ; triangulation by R.D. Cutts, asst. & A.F. Rodgers, sub-asst. ; topography by R.D. Cutts, asst., A.M. Harrison & A.F. Rodgers, sub-assts. ; hydrography by the party under the command of Lieut. Comdg. James Alden, U.S.N. assist. It was published by The Survey in 1877. Scale 1:50,000. Covers the San Francisco Bay Area. The image inside the map neatline is georeferenced to the surface of the earth and fit to the California Zone III State Plane Coordinate System NAD83 (in Feet) (Fipszone 0403). All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows coastal features such as lighthouses, buoys, beacons, rocks, channels, points, coves, islands, bottom soil types, wharves, and more. Includes also selected land features such as roads, railroads, drainage, land cover, selected buildings, towns, and more. Relief shown by hachures and spot heights; depths by sounding, shading, and contours. Includes inset map: Sub-sketch of entrance to San Francisco Bay (Scale 1:400,000), and inset views: View of the entrance to San Francisco Bay, Alcatraz N.E. by E. 1/2 (by compass 10 miles) -- View of the entrance to San Francisco Bay from Yerba Buena Id. -- View of the entrance to San Pablo Bay from near Angel Id. Also includes text and tables. This layer is part of a selection of digitally scanned and georeferenced historic maps from The Harvard Map Collection as part of the Imaging the Urban Environment project. Maps selected for this project represent major urban areas and cities of the world, at various time periods. These maps typically portray both natural and manmade features at a large scale. The selection represents a range of regions, originators, ground condition dates, scales, and purposes.

San Francisco Bay Area, California, Nautical Chart, 1889 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: San Francisco entrance, California, United States Coast and Geodetic Survey ; eng.d by J. Enthoffer, E.A. Maedel, J.J. Young, W.A. Thompson, H.M. Knight, A. Peterson, and J.G. Thompson; red.r dr.ng by A. Lindenkohl, C. Junken, E. Molkow, E.J. Sommer. It was published by U.S.C. & G.S., printed March 15, 1889, corrected to April 12, 1889. Scale 1:40,000. Covers the San Francisco Bay Area. The image inside the map neatline is georeferenced to the surface of the earth and fit to the California Zone III State Plane Coordinate System NAD83 (in Feet) (Fipszone 0403). All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows coastal features such as lighthouses, buoys, beacons, rocks, channels, points, coves, islands, bottom soil types, wharves, and more. Includes also selected land features such as roads, railroads, drainage, land cover, selected buildings, towns, and more. Relief shown by contours and spot heights; depths by soundings. Includes notes, tables, and list of authorities. This layer is part of a selection of digitally scanned and georeferenced historic maps from The Harvard Map Collection as part of the Imaging the Urban Environment project. Maps selected for this project represent major urban areas and cities of the world, at various time periods. These maps typically portray both natural and manmade features at a large scale. The selection represents a range of regions, originators, ground condition dates, scales, and purposes.

San Francisco, California 1915 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: San Francisco and vicinity. It was published by Southern Pacific Company in 1915. Scale [ca. 1:30,800]. The image inside the map neatline is georeferenced to the surface of the earth and fit to the California Zone III State Plane Coordinate System NAD83 (in Feet) (Fipszone 0403). All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as roads, railroads, street car routes, drainage, selected public buildings, parks, cemeteries, wharves, and more. Also shows the grounds of Panama-Pacific International Exposition. Relief is shown by hachures. Includes inset: San Francisco and adjacent territory. Also includes indexes to points of interest. This layer is part of a selection of digitally scanned and georeferenced historic maps from The Harvard Map Collection as part of the Imaging the Urban Environment project. Maps selected for this project represent major urban areas and cities of the world, at various time periods. These maps typically portray both natural and manmade features at a large scale. The selection represents a range of regions, originators, ground condition dates, scales, and purposes.

A study of the impact of airports on the market value of real estate in the adjacent areas: New York International Airport, Chicago-O'Hare International Airport, San Francisco International Airport, (United States Naval Air Station, Glenview, Illinois), (United States Naval Air Station, Moffett Field, California)

Cover title: Airport study, 1960.

Men, money and mud : the story of the San Francisco International Airport /

Mode of access: Internet.

The ports of San Francisco, Oakland, Alameda, Richmond, and upper San Francisco Bay, California.

Includes index.

Cruise Speed Reduction for Ground Delay Programs: A Case Study for San Francisco International Airport Arrivals

Ground Delay Programs (GDP) are sometimes cancelled before their initial planned duration and for this reason aircraft are delayed when it is no longer needed. Recovering this delay usually leads to extra fuel consumption, since the aircraft will typically depart after having absorbed on ground their assigned delay and, therefore, they will need to cruise at more fuel consuming speeds. Past research has proposed speed reduction strategy aiming at splitting the GDP-assigned delay between ground and airborne delay, while using the same fuel as in nominal conditions. Being airborne earlier, an aircraft can speed up to nominal cruise speed and recover part of the GDP delay without incurring extra fuel consumption if the GDP is cancelled earlier than planned. In this paper, all GDP initiatives that occurred in San Francisco International Airport during 2006 are studied and characterised by a K-means algorithm into three different clusters. The centroids for these three clusters have been used to simulate three different GDPs at the airport by using a realistic set of inbound traffic and the Future Air Traffic Management Concepts Evaluation Tool (FACET). The amount of delay that can be recovered using this cruise speed reduction technique, as a function of the GDP cancellation time, has been computed and compared with the delay recovered with the current concept of operations. Simulations have been conducted in calm wind situation and without considering a radius of exemption. Results indicate that when aircraft depart early and fly at the slower speed they can recover additional delays, compared to current operations where all delays are absorbed prior to take-off, in the event the GDP cancels early. There is a variability of extra delay recovered, being more significant, in relative terms, for those GDPs with a relatively low amount of demand exceeding the airport capacity.

San Francisco Bay regional sediment management strategy development

The San Francisco Bay Conservation and Development Commission (BCDC), in continued partnership with the San Francisco Bay Long Term Management Strategies (LTMS) Agencies, is undertaking the development of a Regional Sediment Management Plan for the San Francisco Bay estuary and its watershed (estuary). Regional sediment management (RSM) is the integrated management of littoral, estuarine, and riverine sediments to achieve balanced and sustainable solutions to sediment related needs. Regional sediment management recognizes sediment as a resource. Sediment processes are important components of coastal and riverine systems that are integral to environmental and economic vitality. It relies on the context of the sediment system and forecasting the long-range effects of management actions when making local project decisions. In the San Francisco Bay estuary, the sediment system includes the Sacramento and San Joaquin delta, the bay, its local tributaries and the near shore coastal littoral cell. Sediment flows from the top of the watershed, much like water, to the coast, passing through rivers, marshes, and embayments on its way to the ocean. Like water, sediment is vital to these habitats and their inhabitants, providing nutrients and the building material for the habitat itself. When sediment erodes excessively or is impounded behind structures, the sediment system becomes imbalanced, and rivers become clogged or conversely, shorelines, wetlands and subtidal habitats erode. The sediment system continues to change in response both to natural processes and human activities such as climate change and shoreline development. Human activities that influence the sediment system include flood protection programs, watershed management, navigational dredging, aggregate mining, shoreline development, terrestrial, riverine, wetland, and subtidal habitat restoration, and beach nourishment. As observed by recent scientific analysis, the San Francisco Bay estuary system is changing from one that was sediment rich to one that is erosional. Such changes, in conjunction with increasing sea level rise due to climate change, require that the estuary sediment and sediment transport system be managed as a single unit. To better manage the system, its components, and human uses of the system, additional research and knowledge of the system is needed. Fortunately, new sediment science and modeling tools provide opportunities for a vastly improved understanding of the sediment system, predictive capabilities and analysis of potential individual and cumulative impacts of projects. As science informs management decisions, human activities and management strategies may need to be modified to protect and provide for existing and future infrastructure and ecosystem needs. (PDF contains 3 pages)

Formas de solidaridad internacional de las ONG OXFAM GB y Caritas Española con el proceso de resistencia civil de la comunidad de paz San Francisco de Asís. Periodo 1997- 2002.

Este estudio de caso analiza las formas de solidaridad internacional de OXFAM Gran Bretaña y Cáritas Española con las dinámicas y procesos de la Comunidad de Paz San Francisco de Asís en el Chocó. Comunidad que surge en medio del desplazamiento forzado en 1997.

Benefit cost analysis applied to behavioral and engineering safety countermeasures in San Francisco, California

The state of the practice in safety has advanced rapidly in recent years with the emergence of new tools and processes for improving selection of the most cost-effective safety countermeasures. However, many challenges prevent fair and objective comparisons of countermeasures applied across safety disciplines (e.g. engineering, emergency services, and behavioral measures). These countermeasures operate at different spatial scales, are funded often by different financial sources and agencies, and have associated costs and benefits that are difficult to estimate. This research proposes a methodology by which both behavioral and engineering safety investments are considered and compared in a specific local context. The methodology involves a multi-stage process that enables the analyst to select countermeasures that yield high benefits to costs, are targeted for a particular project, and that may involve costs and benefits that accrue over varying spatial and temporal scales. The methodology is illustrated using a case study from the Geary Boulevard Corridor in San Francisco, California. The case study illustrates that: 1) The methodology enables the identification and assessment of a wide range of safety investment types at the project level; 2) The nature of crash histories lend themselves to the selection of both behavioral and engineering investments, requiring cooperation across agencies; and 3) The results of the cost-benefit analysis are highly sensitive to cost and benefit assumptions, and thus listing and justification of all assumptions is required. It is recommended that a sensitivity analyses be conducted when there is large uncertainty surrounding cost and benefit assumptions.

The Municipal Budgetary Response to Changing Labor Costs: The Case of San Francisco

"This paper analyzes how expenditures of the city of San Francisco were altered in response to changes in municipal labor costs over the period 1945 through 1976. A hybrid of the "demands" and the "organizational" models of budgeting is used to measure the budgetary response to changes in the relative prices of labor inputs. Descriptive and econometric evidence reveals significant adjustments both among and within departments in reaction to changes in relative labor costs. The empirical evidence demonstrates that the city's budgetary process is guided by simple allocative rules modified by price-responsive adjustments."