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Richard E. Smith

Publications and source records attributed to Richard E. Smith.

17 recordsLinked to original sources
USGS2026

Determining Volcanic Risk in Auckland (DEVORA) Research Programme—A transdisciplinary approach to address the challenge of distributed volcanism in an urban environment

The Determining Volcanic Risk in Auckland (DEVORA) Research Programme was launched in 2008 to address the challenges associated with monogenetic volcanism in an urban setting and to enhance volcanic risk management in Tāmaki Makaurau Auckland in Aotearoa New Zealand. It is a multi-agency, increasingly transdisciplinary (defined here as research that transcends traditional disciplinary boundaries by integrating diverse types of knowledge, perspectives, and methods from academic and non-academic participants to create novel solutions to complex problems), and collaborative research program jointly led by Waipapa Taumata Rau University of Auckland and Earth Sciences New Zealand (ESNZ; formerly GNS Science), with core funding from Natural Hazards Commission Toka Tū Ake (NHC; formerly the Earthquake Commission, EQC) and Te Kaunihera o Tāmaki Makaurau Auckland Council (AC). The primary research focus of DEVORA is to investigate the geologic history, volcanic hazards, and risk posed by the basaltic intraplate Auckland Volcanic Field. Disruption from ash fall and gas from other Aotearoa New Zealand volcanoes is also considered. DEVORA’s work to explore exposure and vulnerability in Tāmaki Makaurau Auckland is also useful for assessing risks from other non-volcanic natural hazards, such as seismic and tsunami hazards. The greater Tāmaki Makaurau Auckland region has an ethnically and socio-economically diverse population of approximately 1.7 million, representing about one-third of the Aotearoa New Zealand population, and hosts critical infrastructure of national significance. The size and nature of the populace, consequential economic base, and important infrastructure within Tāmaki Makaurau Auckland mean that the effects of a volcanic eruption would be felt nationally, including through the disruption of air travel to Aotearoa New Zealand. The hazards from such an eruption could potentially affect hundreds of thousands of people, businesses, and lifelines (critical infrastructure). A considerable challenge for emergency and risk managers is the monogenetic nature of the volcanic field. It is not known where or when the next eruption will occur, how much warning we may get before an eruption, nor how an eruption and its effects might unfold. In this contribution, we highlight the concept and collaborative intent of the DEVORA Programme and show how it has evolved over the 16 years since its inception. We describe how DEVORA has unified more than 100 researchers (including more than 50 graduate students) and numerous stakeholders to address key issues facing Tāmaki Makaurau Auckland and describe how research findings are being implemented into policy and communicated to stakeholder agencies and the public. We also illustrate the broader influence of the DEVORA Programme and provide some learnings that might benefit others embarking on similar integrated projects, especially those focused on distributed volcanism in and near populated areas.

Auckland↗
USGS2010

Mercury-contaminated hydraulic mining debris in San Francisco Bay

The hydraulic gold-mining process used during the California Gold Rush and in many developing countries today contributes enormous amounts of sediment to rivers and streams. Commonly, accompanying this sediment are contaminants such as elemental mercury and cyanide used in the gold extraction process. We show that some of the mercurycontaminated sediment created by hydraulic gold mining in the Sierra Nevada, between 1852 and 1884, ended up over 250 kilometers (km) away in San Francisco Bay; an example of the far-reaching extent of contamination from such activities. A combination of radionuclide dating, bathymetric reconstruction, and geochemical tracers were used to distinguish the hydraulic mining sediment from sediment deposited in the bay before hydraulic mining started (pre-Gold Rush sediment) and sediment deposited after hydraulic mining stopped (modern sediment). Three San Francisco Bay cores were studied as well as source material from the abandoned hydraulic gold mines and river sediment between the mines and bay. Isotopic and geochemical compositions of the core sediments show a geochemical shift in sediment deposited during the time of hydraulic mining. The geochemical shift is characterized by a decrease in εNd, total organic carbon (TOC), Sr and Ca concentrations, Ca/Sr, and Ni/Zr; and, an increase in 87Sr/86Sr, Al/Ca, Hg concentrations, and quartz/plagioclase. This shift is in the direction of the geochemical signature of sediments from rivers and gold mines in hydraulic mining areas. Mixing calculations using Nd isotopes and concentrations estimate that the hydraulic mining debris comprises up to 56% of the sediment in core sediments deposited during the time of hydraulic mining. The surface sediment of cores taken in 1990 were found to contain up to 43% hydraulic mining debris, reflecting a continuing remobilization and redistribution of the debris within the bay and transport from the watershed. Mercury concentrations in pre-Gold Rush sediment range between 0.03 and 0.08 μg g-1. In core sediments that have characteristics of the gold deposits and were deposited during the time of hydraulic mining, mercury concentrations can be up to 0.45 μg/g. Modern sediment (post-1952 deposition) contains mercury concentrations up to 0.79 μg/g and is likely a mix of hydraulic mining mercury and mercury introduced from other sources.

California↗
USGS2004

Deposition, erosion, and bathymetric change in South San Francisco Bay: 1858-1983

Since the California Gold Rush of 1849, sediment deposition, erosion, and the bathymetry of South San Francisco Bay have been altered by both natural processes and human activities. Historical hydrographic surveys can be used to assess how this system has evolved over the past 150 years. The National Ocean Service (NOS) (formerly the United States Coast and Geodetic Survey (USCGS), collected five hydrographic surveys of South San Francisco Bay from 1858 to 1983. Analysis of these surveys enables us to reconstruct the surface of the bay floor for each time period and quantify spatial and temporal changes in deposition, erosion, and bathymetry. The creation of accurate bathymetric models involves many steps. Sounding data was obtained from the original USCGS and NOS hydrographic sheets and were supplemented with hand drawn depth contours. Shorelines and marsh areas were obtained from topographic sheets. The digitized soundings and shorelines were entered into a Geographic Information System (GIS), and georeferenced to a common horizontal datum. Using surface modeling software, bathymetric grids with a horizontal resolution of 50 m were developed for each of the five hydrographic surveys. Prior to conducting analyses of sediment deposition and erosion, we converted all of the grids to a common vertical datum and made adjustments to correct for land subsidence that occurred from 1934 to 1967. Deposition and erosion that occurred during consecutive periods was then computed by differencing the corrected grids. From these maps of deposition and erosion, we calculated volumes and rates of net sediment change in the bay. South San Francisco Bay has lost approximately 90 x 106 m3 of sediment from 1858 to 1983; however within this timeframe there have been periods of both deposition and erosion. During the most recent period, from 1956 to 1983, sediment loss approached 3 x 106 m3/yr. One of the most striking changes that occurred from 1858 to 1983 was the conversion of more than 80% of the tidal marsh to salt ponds, agricultural, and urban areas. In addition, there has been a decline of approximately 40% in intertidal mud flat area. Restoration of these features will require a detailed understanding of the morphology and sediment sources of this complex system.

California↗
USGS1998

Sedimentation and bathymetric change in San Pablo Bay: 1856-1983

A long-term perspective of erosion and deposition in San Francisco Bay is vital to understanding and managing wetland change, harbor and channel siltation, and other sediment-related phenomena such as particle and particle-associated substance (pollutants, trace metals, etc.) transport and deposition. A quantitative comparison of historical hydrographic surveys provides this perspective. This report presents results of such a comparison for San Pablo Bay, California. Six hydrographic surveys from 1856 to 1983 were analyzed to determine long-term changes in the sediment system of San Pablo Bay. Each survey was gridded using surface modeling software. Changes between survey periods were computed by differencing grids. Patterns and volumes of erosion and deposition in the Bay are derived from difference grids. More than 350 million cubic meters of sediment was deposited in San Pablo Bay from 1856 to 1983. This is equivalent to a Baywide accumulation rate of approximately 1 cm/yr. However, sediment deposition was not constant over time or throughout the Bay. Over two-thirds of that sediment was debris from hydraulic mining that accumulated from 1856 to 1887. During this period, deposition occurred in nearly the entire Bay. In contrast, from 1951 to 1983 much of the Bay changed from being depositional to erosional as sediment supply diminished and currents and waves continued to remove sediment from the Bay. The decrease in sediment supply is likely the result of upstream flood-control and water-distribution projects that have reduced peak flows, which are responsible for the greatest sediment transport. One consequence of the change in sedimentation was a loss of about half of the tidal flat areas from the late 1800's to the 1980's. Change in sedimentation must also have affected flow in the Bay, areas where polluted sediments were deposited, exchange of sediment between the nearshore and wetlands, and wave energy reaching the shoreline that was available to erode wetlands. Further work is needed. Studies of historical wetland change and the relationship between change and man-made and natural influences would be valuable for developing sound wetland management plans. Additionally, extending the historical hydrographic and wetland change analyses eastward into Suisun Bay will improve the understanding of the North Bay sediment system.

California↗
USGS1998

An overview of San Francisco Bay PORTS

The Physical Oceanographic Real-Time System (PORTS) provides observations of tides, tidal currents, and meteorological conditions in real-time. The San Francisco Bay PORTS (SFPORTS) is a decision support system to facilitate safe and efficient maritime commerce. In addition to real-time observations, SFPORTS includes a nowcast numerical model forming a San Francisco Bay marine nowcast system. SFPORTS data and nowcast numerical model results are made available to users through the World Wide Web (WWW). A brief overview of SFPORTS is presented, from the data flow originated at instrument sensors to final results delivered to end users on the WWW. A user-friendly interface for SFPORTS has been designed and implemented. Appropriate field data analysis, nowcast procedures, design and generation of graphics for WWW display of field data and nowcast results are presented and discussed. Furthermore, SFPORTS is designed to support hazardous materials spill prevention and response, and to serve as resources to scientists studying the health of San Francisco Bay ecosystem. The success (or failure) of the SFPORTS to serve the intended user community is determined by the effectiveness of the user interface.

California↗
USGS1998

A nowcast model for tides and tidal currents in San Francisco Bay, California

National Oceanographic and Atmospheric Administration (NOAA) installed Physical Oceanographic Real-Time System (PORTS) in San Francisco Bay, California to provide observations of tides, tidal currents, and meteorological conditions. PORTS data are used for optimizing vessel operations, increasing margin of safety for navigation, and guiding hazardous material spill prevention and response. Because tides and tidal currents in San Francisco Bay are extremely complex, limited real-time observations are insufficient to provide spatial resolution for variations of tides and tidal currents. To fill the information gaps, a highresolution, robust, semi-implicit, finite-difference nowcast numerical model has been implemented for San Francisco Bay. The model grid and water depths are defined on coordinates based on Mercator projection so the model outputs can be directly superimposed on navigation charts. A data assimilation algorithm has been established to derive the boundary conditions for model simulations. The nowcast model is executed every hour continuously for tides and tidal currents starting from 24 hours before the present time (now) covering a total of 48 hours simulation. Forty-eight hours of nowcast model results are available to the public at all times through the World Wide Web (WWW). Users can view and download the nowcast model results for tides and tidal current distributions in San Francisco Bay for their specific applications and for further analysis.

California↗
USGS1997

Bottom boundary layer in south San Francisco Bay, California

Detailed velocity distributions within the benthic turbulent boundary layer were measured by a Broad Band Acoustic Doppler Current Profiler (BB-ADCP) in South San Francisco Bay, California. In "mode 5", the BB-ADCP was able to measure velocity in 5 cm increments. The validation of these measurements was achieved by comparing the BB-ADCP measurements with the velocities measured by a Narrow Band Acoustic Doppler Current Profiler (NB-ADCP) in close proximity. There were thirty-three (33) velocity time-series measured by the BB-ADCP beginning at 7 cm above bed and extending to 175 cm in water column for about two weeks. The velocities from locations at 7 cm and 12 cm above the bed were determined to be of lower accuracy, and they were not used in estimates of friction velocity, u.. The values of u. at 95% confidence level were determined with relative error less than 20%. The time-series of u. varied with velocity outside of the boundary layer, and responded to spring-neap tidal variations. Attempts to use acoustic backscatterance echo intensity to measure suspended sediment concentration showed prom ise, and merit consideration in future studies.

California↗
USGS1995

Seasonal/yearly salinity variations in San Francisco Bay

The ability of resource agencies to manage fish, wildlife and freshwater supplies of San Francisco Bay estuary requires an integrated knowledge of the relations between the biota and their physical environment. A key factor in these relations is the role of salinity in determining both the physical and the biological character of the estuary. The saltiness of the water, and particularly its seasonal and interannual patterns of variability, affects which aquatic species live where within the estuary. Salinity also determines where water can and cannot be diverted for human consumption and irrigated agriculture, and plays a role in determining the capacity of the estuary to cleanse itself of wastes. In short, salinity is a fundamental property of estuarine physics and chemistry that, in turn, determines the biological characteristics of each estuary. Freshwater is a major control on estuarine salinity. Most freshwater supplied to the Bay is from river flow through the Delta, which is primarily runoff from the Sierra Nevada. Most contaminants in San Francisco Bay are from the Sacramento/San Joaquin Valley and the local watershed around the Bay rather than the sea or atmosphere. Land is the primary source of freshwater and freshwater serves as a tracer of land-derived substances such as the trace metals (copper, lead and selenium), pesticides and plant nutrients (nitrate and phosphate). The U.S. Geological Survey is collaborating with other agencies and institutions in studying San Francisco Bay salinity using field observations and numerical simulations to define the physical processes that control salinity. The issues that arise from salinity fluctuations, however, differ in the northern and southern parts of the bay. In North Bay we need to know how salinity responds to freshwater flow through the Sacramento/San Joaquin Delta; this knowledge will benefit water managers who determine how much delta flow is needed a) to protect freshwater supplies for municipal water use and b) modulate salinity for a healthy estuary. In South Bay we need to know where the freshwater comes from (the distant Delta or local streams) to sort out the sources of a) contamination or b) dilution.

California↗
USGS1980

Physical and chemical properties of San Francisco Bay waters, 1977

Basic data on the physical and chemical properties of San Francisco Bay waters are presented here. Samples were collected over the period March-November 1977 at approximately monthly intervals at 36 stations. The stations were located along the axis of the Bay from Calaveras Point in South San Francisco Bay to the town of Rio Vista on the Sacramento River. The samples were analyzed for the following core parameters: salinity, temperature, light transmission, chlorophyll a fluorescence, light extinction, turbidity, dissolved oxygen, pH, pCO 2 , orthophosphate, nitrate+nitrite, nitrite, ammonia, and silicate. Additional analyses were performed on selected discrete samples collected for particulate organic carbon, chlorophyll a, alkalinity, total CO 2 and suspended particulate matter. The results of these analyses and the analytical methods used are documented in this report.

California↗
USGS1980

Physical and chemical properties of the Potomac River and environs, April-May 1978

Basic data on the physical and chemical properties measured over the period 24 April through 4 May 1978 on the tidally influenced Potomac River and estuary are presented herein. One 28-hour time series, 45 vertical profiles, and approximately 170 surface observations were made of the distributions of salinity, temperature, light transmission, chlorophyll-a fluorescence, dissolved oxygen, partial pressure of CO2, orthophosphate, nitrate+nitrite, nitrite, ammonia, and silicate. Additional analyses were performed on discrete samples collected for particulate organic carbon, alkalinity, pH, suspended particulate matter, total phosphate, total nitrogen, total dissolved phosphate, and total dissolved nitrogen.

Maryland, Virginia, West Virginia↗
USGS1980

Physical and chemical properties of the Potomac River and environs, August 1978

Basic data on the physical and chemical properties measured over the period 21 August through 31 August 1978 on the tidally influenced Potomac River and estuary are presented herein. Forty-two vertical profiles, and approximately 170 surface observations were made of the distributions of salinity, temperature, light transmission, chlorophyll-a fluorescence, dissolved oxygen, partial pressure of CO2, orthophosphate, nitrate+nitrite, nitrite, ammonia, and silicate. Additional analyses were performed on discrete samples collected for particulate organic carbon, alkalinity, pH, suspended particulate matter, total phosphate, total nitrogen, total dissolved phosphate, and total dissolved nitrogen.

Maryland, Virginia, West Virginia↗
USGS1979

Physical and chemical properties of San Francisco Bay waters, 1969-1976

Basic data on the physical and chemical properties of San Francisco Bay are presented here. Samples were collected over the period 1969-1976 at approximately six-week intervals at 36 stations. The stations were located along the axis of the Bay from Calaveras Point in South San Francisco Bay to the town of Rio Vista on the Sacramento River. On most cruises vertical profiles of the water properties were taken at 12 of the 36 stations. The samples were analyzed for the following core parameters: salinity, temperature, light transmission, chlorophyll a fluorescence, dissolved oxygen, orthophosphate, nitrate+nitrite, nitrite, ammonia, and silicate. Other analyses performed on selected samples included: particulate organic carbon, alkalinity, pH, pCO 2 , and suspended particulate weight. The results of these analyses and the analytical methods used are documented in this report.

California↗