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Assessment of Lingering Oil in PWS & GOA Quarterly Tasks

2008 Quarterly Project Tasks:

1st Quarter Tasks (October 1, 2007 - December 31, 2007)
Status: Complete

Tasks to be performed:

Project Plan Modification: The original project plan was designed to produce maps of the location and amounts of lingering oiled sediments and EVOS oil using a spatial probability model based on a statistically rigorous field sampling program. The plan called for the following five tasks. 1. Construct a preliminary probability model from existing information. 2. Design a statistically rigorous sampling plan to collect additional field data necessary to refine the preliminary probability model. 3. Conduct the field sampling in PWS and the northern GOA. 4. Construct a refined probabilistic model of the spatial extent of lingering oil. 5. Prepare a final report We have successfully completed all work through Task 4. The initial probability model was constructed and used to inform the field sampling campaign. Data collected during field sampling in the summer of 2007 yielded both the raw materials for an improved probabilistic model, which has already been constructed, and valuable and documented practical insights into the geomorphologic factors driving the persistence of subsurface lingering oil. The fieldwork and subsequent analysis has brought to light additional issues inherent in the task of estimating the distribution of lingering oil and suggested a modified approach for the remainder of the work. As such, we propose the following no-cost modifications to the work plan and schedule to maximize the ability of the data and products generated by the project to more accurately estimate the true distribution of lingering subsurface oil. The foundation of this project is to build a model to relate the presence and nature of subsurface oil at investigated sites along the shorelines of Prince William Sound (PWS) and the Gulf of Alaska (GOA) to spatial digital data that exist synoptically across the area so we can make predictions at unsampled locations. During progress thus far, we believe we have constructed the best model possible given the data available. The model accuracy can be characterized as good. However, we have also learned much about the extent to which fine-scale geomorphologic features control the persistence of subsurface oil. There are no existing digital data that describe these features synoptically across the study area. Therefore, we propose the following additional three tasks. First, we propose to use the refined probabilistic model to select a subset of the shorelines of PWS and GOA that meet certain defined criteria for having high subsurface oil encounter probabilities. Aerial videography collected by the Trustee funded in FY07 ShoreZone project would then be used to derive new high-resolution digital data describing these fine-scale geomorphologic features for all of these high-priority shorelines. We have already preliminarily evaluated the utility of this videography for this purpose. Secondly, we propose a limited field survey of directed sampling for subsurface oil in PWS to test the refined model and enable construction of a final model based, in part, upon these new data. The field survey would, in general, use a rapid assessment field protocol based upon the field protocols used in summer 2007. We would survey 30-40 additional sites in the summer of 2008. Third, the 2008 data would be used to construct a final probabilistic model of the spatial extent of lingering oil Project Schedule Modification We thus propose a new list of tasks with the following modifications to the schedule. 1. Construct a preliminary probability model from existing information. 2. Design a statistically rigorous sampling plan to collect additional field data necessary to refine the preliminary probability model. 3. Conduct the field sampling in PWS and the northern GOA. 4. Construct a refined probabilistic model of the spatial extent of lingering oil. 5. Develop new high-resolution data layers for high priority shorelines. 6. Conduct a second round of limited field sampling in PWS. 7. Construct a final probabilistic model of the spatial extent of lingering oil. 8. Prepare final report.

Progress report:

Completed: Task 4. Develop refined probability model

2nd Quarter Tasks (January 1, 2008 - March 31, 2008)
Status: Complete

Tasks to be performed:

Task 4. Develop refined probability model To be completed by 15 March 2008 Task 5. Produce new high-resolution data layers for high priority shorelines.

Progress report:

Completed

3rd Quarter Tasks (April 1, 2008 - June 30, 2008)
Status: Complete

Tasks to be performed:

Task 5. Produce new high-resolution data layers for high priority shorelines. To be completed by 30 April 2008 Task 6. Prepare for and conduct field sampling To be completed by 30 June 2008

Progress report:

Completed. Field work to be extended through Aug

4th Quarter Tasks (July 1, 2008 - September 30, 2008)
Status: Complete

Tasks to be performed:

Task 7. Construct a final probabilistic model of the spatial extent of lingering oil. To be completed by 30 September 2008 Task 8 Prepare Final Report: To be completed by 15 April 2009

Progress report:

see annual report http://www.evostc.state.ak.us/Files.cfm?doc=/Store/AnnualReports/2008-070801-Annual.pdf&

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