Mineralogical compositions of sediment samples from the San Francisco Bay coastal system

The mineralogical compositions of 119 samples collected from throughout the San Francisco Bay coastal system, including bayfloor and seafloor, area beaches, cliff outcrops, and major drainages, were determined using X-ray diffraction (XRD). Comparison of the mineral concentrations and application of statistical cluster analysis of XRD spectra allowed for the determination of provenances and transport pathways. The use of XRD mineral identifications provides semi-quantitative compositions needed for comparisons of beach and offshore sands with potential cliff and river sources, but the innovative cluster analysis of XRD diffraction spectra provides a unique visualization of how groups of samples within the San Francisco Bay coastal system are related so that sand-sized sediment transport pathways can be inferred. The main vector for sediment transport as defined by the XRD analysis is from San Francisco Bay to the outer coast, where the sand then accumulates on the ebb tidal delta and also moves alongshore. This mineralogical link defines a critical pathway because large volumes of sediment have been removed from the Bay over the last century via channel dredging, aggregate mining, and borrow pit mining, with comparable volumes of erosion from the ebb tidal delta over the same period, in addition to high rates of shoreline retreat along the adjacent, open-coast beaches. Therefore, while previously only a temporal relationship was established, the transport pathway defined by mineralogical and geochemical tracers support the link between anthropogenic activities in the Bay and widespread erosion outside the Bay. The XRD results also establish the regional and local importance of sediment derived from cliff erosion, as well as both proximal and distal fluvial sources. This research is an important contribution to a broader provenance study aimed at identifying the driving forces for widespread geomorphic change in a heavily urbanized coastal-estuarine system.

Bank erosion control with vegetation, San Francisco Bay, California /

Cover title.

The history of the Beach Erosion Board, U.S. Army, Corps of Engineers, 1930 -63 /

Issued August 1977.

Beach erosion and accretion at Virginia Beach, Virginia, and vicinity /

"December 1977."

Analysis of coastal sediment transport processes from Wrightsville Beach to Fort Fisher, North Carolina /

A comprehensive engineering analysis of the coastal sediment transport processes along a 42-kilometer segment of the North Carolina shoreline from Wrightsville Beach to Fort Fisher is presented. Included in the analysis is an interpretation of the littoral processes, longshore transport, and the behavior and success of beach nourishment projects at Wrightsville Beach and Carolina Beach, North Carolina. The historical position of the MLW, MSL, and MHW contours, relative to a fixed base line, is plotted for the period between 1964 and 1975. An equivalent volumetric erosion or accretion between successive surveys is determined by multiplying the average excursion distance of the contours by a constant of proportionality. The plots of excursion distance versus time for the MLW, MSL, and MHW contours also show the time response of the beach fills. This response is described by a mathematical function. The alongshore components of wave-induced energy flux are also determined within the study area through wave refraction analysis. This information, together with the information on volumetric change, is used in a sediment budget analysis to determine the coefficient of alongshore sediment transport and the inlet trapping characteristics. (Author).

The effect of structures and lake level on bluff and shore erosion in Berrien County, Michigan, 1970-74 /

Cover title.

Shoreline erosion study, Pleasure Island, Texas /

"Prepared for U.S. Army Engineer District, Galveston, Galveston, Texas."

A collection of storm erosion field data /

Mode of access: Internet.

Coastal processes at Sea Bright to Ocean Township, New Jersey.

"August 1988."

History of erosion and erosion control efforts at Tybee Island, Georgia /

"February 1985."

Engineering analysis of beach erosion at Homer Spit, Alaska /

Includes abstract.

Coastal processes study of the Oceanside, California, littoral cell : final report /

"August 1978."

Shoreline change and storm-induced beach erosion modeling : a collection of seven papers /

Cover title.

Coastal response to the Port Sheldon jetties at Pigeon Lake, Michigan /

Cover title.

A method for estimating long-term erosion rates from a long-term rise in water level /

"May 1979."