A video-monitored oil-seep capture tent and an intertidal seep tank were developed and deployed to quantify emissions in shallow (5-m) nearshore waters and at an intertidal location at Summerland Beach, California. At two sites, where bubbles appeared clear, gas to oil ratios were 105:1; at a site where bubbles were dark, gas to oil ratio was 8.4:1. Nearshore oil emissions were conservatively estimated at 0.8 L dy’1. The size distribution of oily bubbles sharply peaked at 1500 µm, and the gas to oil ratio varied between bubbles. Oil affected the bubble's buoyancy and hydrodynamics. Time series of seabed emissions showed oil was mostly released in pulses. Several mechanisms that may cause variability in oil emissions were proposed. Intertidal oil emission were estimated a 12 L dy−1. Also, beach surveys showed less than trace amounts of beached oil and no oiled fauna over a 19-month period.
From 1992 until 2002, oiled birds, predominantly common murres, were found along the central California coastline during the winter months, but no significant oil slicks were observed. These repeat “mystery” oil spills puzzled investigators for 10 years while several similar cases of bird impacts occurred from November through February to varying degrees each year. In 2001, the same pattern began yet again. The response to oiled wildlife was the most significant to date. Extending over 220 miles of coastline, more than 2000 birds were recovered and transported for care to California's Oiled Wildlife Care Network (OWCN) facility. Motivated by this serious threat to wildlife, federal and state investigators utilized the historical data collected in previous cases combined with current technology to solve the mystery. An extensive Oil Spill Source Identification Task Force was formed consisting of 20 federal and state agents working together to get to the source of the problem. Through these current technologies, including oil sample analysis; satellite, aerial, and on-water observations; and hindcasting, the Task Force was able to eliminate alternative possibilities and focus the investigation on the last potential source, a sunken shipwreck. The Task Force sifted through four different databases of sunken vessels indicating over 700 shipwrecks off of the San Francisco coast alone to establish eight ships as potential targets. During the first underwater search planned to visually investigate each of these vessels, oil was located in the surface waters above the SS JACOB LUCKENBACH, a C-3 freighter sunk in 1953, 17 miles southwest of the Golden Gate Bridge. Analyses of oil samples collected from the vessel's tanks confirmed the LUCKENBACH as the source impacting California seabirds. Further research showed that all possible responsible parties have been absolved of any liability regarding the sinking of the LUCKENBACH. After spending over $3 million on the 1997–1998 and 2001–2002 incidents for the wildlife response alone and with no party from which to recover the funds, the spill response community is faced with an enormous financial task for the future: responding to inevitable oil spills off the coasts of the United States from thousands of deteriorating shipwrecks sunk decades ago with, in most cases, no responsible parties.
Traditionally, spill response effectiveness has been measured by cost per volume of oil spilled. However, this measurement is misleading and arbitrary. Measuring the cost of response per gallon (or barrel) spilled does not adequately account for the value of environmental and economic injuries that were minimized or prevented through appropriate response actions. The authors discuss the principles underlying an evaluation of spill response benefit and present the results of their work in progress to compare the economic and environmental benefits gained by minimizing injuries through response against the cost of conducting that response. This process, which we call response benefit analysis (RBA), uses a quantitative and/or qualitative evaluation of resources protected and rehabilitated as a result of spill response actions. As a pilot study, the authors examined the South Traffic Lane Spill (T/V Command) off the San Francisco peninsula in September 1998. This spill involved an approximate 6,000 gallons of oil, discharged 12 miles offshore, with response costs of $1.03 million. The analysis concluded that significant environmental and economic benefits were realized by conducting a proactive response that would not normally be considered by reporting cost per barrel spilled alone. This methodology presents a conceptual framework and needs to be further developed and tested to enable the spill response community to conduct response benefit analysis locally.
The Shoreline Cleanup and Assessment Technique (SCAT) process, from initial reconnaissance, to generation of Shoreline Treatment Recommendations (STRs) and signoff, is an integral part of oil spill response operations. It is and should remain flexible and scalable based on spill conditions. Several challenging spill responses have contributed to the continuing evolution of the SCAT program. This review examines best practices and unique applications for the SCAT process, coordination within the Incident Command System (ICS), field implementation and tools, and data management. While the basic SCAT process remains the same, the detailed steps can vary greatly from spill to spill. STRs and incident specific forms may be required, additional review procedures for documents and shorelines may occur, endpoints and signoff can become extremely complex, intermediate plans may be generated to manage complexity, and various regulatory consultations may be necessary. Within the ICS, the SCAT program is typically part of the Environmental Unit under the Planning Section, but requires close coordination with the Operations Section. The use of SCAT- Operations Liaisons (both as having Operations on SCAT teams during surveys and as having SCAT team members work with Operations during actual cleanup) is a best practice to improve coordination and treatment effectiveness throughout the response. Field forms, data collection tools, and SCAT staff roles are evolving. The trials of electronic data collection with field computers continue; use of imagery, GPS, and GIS are ever increasing and necessary; and the roles and coordination of various types of field monitors/observers during cleanup operations need to be carefully defined. SCAT team members need to be well-trained, and field calibration should occur regularly within and among teams. SCAT data management now requires dedicated staff and computer data management systems in all but the smallest of spills. The need for high quality data, rapid analysis, and generation of useful products to a varied audience is becoming the expected standard. However, with these expectations come new procedures and specialized skills. QA/QC of field data is critical to all evaluations and products. Specialized databases have become robust enough to handle the most complex SCAT data and output requirements, and GIS tools can quickly generate a variety of necessary map products for multiple users. These functions require skills not found with typical SCAT field team members. In this paper, we will examine some of the recent advances and unique applications to the SCAT process.
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