2.0 Alternatives Considered
A comparison of the two action alternatives reveals no issue areas where one alternative would have a
significant impact that another alternative would lessen or avoid. In fact, given project design features and
the monitoring and implementation commitments described in Sections 2.4 and 2.5, neither action
alternative would result in significant impacts. There would be only minor differences in terms of potentially
adverse impacts. For the issue areas of geology and soils, coastal wetlands, water resources, land and
water use, aesthetics, socioeconomics, structures and utilities, traffic, air quality and noise the relative
difference would be very minor. For the issue areas of biological resources, cultural resources and public
health and safety there would be incrementally variable impacts.
For the issue area of biology, the incremental difference would be related to indirect sedimentation impacts.
Under Alternative 1, model-predicted, worst-case potential impacts would occur withpartialsedimentation
on up to 3.2 acres of reef near three receiver sites, which support giant kelp, 0.3 acre at one reef which
has feather boa, and 0.24 acre at a single reef which has some surfgrass. Long-term impacts would not be
significant because surfgrass leaves would extend well above the predicted sediment layer and allow for
recovery, and the kelp areas are either sparse, subject only to short-term sediment coverage, and/or not
within the historic areas of kelp persistence. Given Alternative 2, which has a different distribution of
receiver sites, worst-case potential impacts due to sedimentation may occur on less than1.78 acres of reef,
at two locations, which support some giant kelp and less than 0.24 acre of reef with surfgrass. These
impacts would also not be significant. Values for Alternative 2 are based, in part, on conservative, and
probably unlikely, sediment depositionnear North Carlsbad from sand placed at the South Oceanside site.
The impact evaluation is based on prior analyses (Department of Navy 1997a) and interpretation of model
predictions for a configuration with greater combined sand volume at Oceanside and North Carlsbad. In
order to disclose potential worst-case impacts, the most conservative interpretationis provided and impacts
are likely overstated. While the relative difference in worst-case impacts is over 1.5 acres, and probably
slight more; since both estimates are based on predictions of an inherently dynamic system (with variable
weather and wave conditions) the level of uncertainty would suggest these different values may not be great
enough to discriminate between the two alternatives.
For the issues of cultural resources and public health and safety the relative difference is also minor, but
appropriate for disclosure. Under both alternatives borrow site dredging has the potential to disturb areas
of moderate to high probability for archaeological resources. Under Alternative 2, the depth of dredging
would be greater by one to three feet at borrow sites SS-1 and MB-1, respectively. Therefore, there
would be a slightly greater opportunity for intrusion into areas that may contain underwater archaeological
resources under Alternative 2. Given the monitoring program to be implemented as described in Section
2.5, the significance conclusion would be identical for both alternatives. For the issue of public health and
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