4.12 Air Quality
Conformance to the SIP is demonstrated by obtaining of appropriate permits from the APCD, or by
demonstrating that emissions would be less than de minimis thresholds established by the EPA.
4.12.2 Alternative 1
Impacts of Alternative 1a
Dredge Operation Emissions
The principal source of emissions from the dredge would be the diesel engines used for dredge propulsion,
driving dredging pumps, and driving electric generators. These would be large diesel engines, and short-
term NOx emission rates would very likely exceed the APCD thresholds for daily emissions, for new and
modified sources. This would require the applicant to obtain an Authority to Construct and Permit to
Operate. As part of the permitting procedure, an Air Quality Impact Analysis would be performed, if
necessary, to provide data relative to the anticipated NOx emissionrates, and to demonstrate that state and
federalair quality standards would not be violated, and there would be no significant impact. The air quality
impact analysis would examine the health risk of toxic pollutant emissions (if any), and the permit process
would assure avoidance of a significant impact. During the dredge operation in San Diego Bay for the
Homeporting project, the Navy obtained a Permit to Operate which specified various conditions regarding
fuel use, dredge limits, etc. A copy of the Permit to Operate for the dredge used on that project is included
in Appendix F. It should be noted that dredge activity for the Homeporting project was related to creating
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a boat basin for a new carrier in San Diego Bay with a much larger quantity of dredged material. The
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conditions in that permit were project-specific and would not necessarily be applicable to the proposed
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action. Alternatively, an individual dredging vessel may be Registered with the California ARB and not
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require a specific air quality permit for this project.
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A second important emissions source would be the smaller vessels supporting the dredge. These vessels
include an anchor scow, a survey boat, and a small boat that would shuttle the dredge crews to shore and
back. A tug would also be used for initial placement and removal of the dredge at each source site. The
support vessels would be powered by diesel or gasoline engines, and would have associated combustion
emissions. Estimated emissions based on very preliminary data were calculated using boat engine size and
emission factor data from a recent EIS analysis for dredging in San Diego Harbor (DON 1999).
Preliminary estimated emissions are shown in Table 4.12-1. These emissions will be finalized through the
permit process.
Page 4.12-2
Regional Beach Sand Project EIR/EA
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