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Notes:
MR. FEHRING: Thank you, Tom, and good morning. Each scientist studying the Bay in some way uses a conceptual model to understand and explain how the various physical, chemical and biological components interact. The NOAA Panel has asked the EIS team to identify the conceptual model that it used in developing the studies of potential changes that would be associated with such a runway reconfiguration. The model we used includes the following features: first, there is a series of physical drivers which include chemical constituents in the sediments and water, hydrodynamic factors such as tides, circulation and waves, the structure and bathymetry of the Bay, sediment bed properties, and other physical conditions such as noise and vibration that occur naturally or occur in the Bay at the existing time. Second, there is a series of biological drivers on this line here that respond to physical drivers that are controlled by them, and these include water quality, sediment transport, including erosion and deposition and re-suspension, habitat, things such as shallow water areas and mudflats, sediment quality, and other conditions such as changes in noise levels or human disturbance over here on the right side. Finally in this model, there is a set of biological communities, and it is replicated on both sides, that respond to these biological drivers. These include benthic and intertidal communities of fish and vertebrates, pelagic communities of fish and plankton, aquatic birds, and marine mammals. In this model, a runway reconfiguration would alter one or more of the physical drivers or the relationship between the physical drivers and the biological drivers, and this in turn may affect the biological communities. The model also recognizes that there are many external factors that would not be affected by a runway reconfiguration in these boxes at the top and bottom. These include physical factors such as sunlight, freshwater inflows, nutrient inputs, and changes in sea level. They also include biological factors such as regional population dynamics, regional long-term habitat succession, and changes in conditions at breeding areas remote from the Bay. Such external factors contribute to uncertainty in making predictions based on this model, along with the uncertainties inherent to any predictive modeling efforts.
I would now like to use this model to illustrate just two of the many questions that were posed by the NOAA Panels I and II that were identified during the scoping process, or developed by the study team to illustrate how the model works. The first question is how would changes in water flow patterns resulting from the runway reconfiguration that alter existing deposition and erosion patterns and existing shallow water habitats. In this instance, the dredging, the changes in bottom elevations due to fill or dredging operations, would alter the relationship between the structure of the Bay and the hydrodynamics. This in turn would alter sediment transport and that in turn would alter habitat itself. Also, any change in bottom elevations in addition to changing the hydrodynamics may directly affect the existence of certain habitats. The second question is how would dredging and construction affect the mobilization of legacy sediment contaminants and the levels of those contaminants in animal species in the Bay. In this instance, the re-suspension of material during the dredging operation would affect the availability of sediment contaminants in the water column and over in the surficial sediments. Changes in the levels of those contaminants would affect tissue levels in both benthic and pelagic fish species, which may in turn affect the levels of those contaminants in birds and mammals.