4.4 Biological Resources
Imperial Beach. This alternative would have an approximately 18 acre footprint of fill and 120,000 cy of
material would be placed. Sand and cobble occur throughout the fill area (refer to Figure 4.4-12) and
there would be no significant direct impacts to marine resources or California grunion.
Indirect Impacts of Sand Placement
This evaluation addressed indirect impacts to shorebirds due to burial of the invertebrate food source, to
various resources due to increased turbidity, and to biological resources from sediment transport.
Shorebird Foraging. There is potential for indirect effects on shorebird foraging from burial of
invertebrates within the footprint of the receiver site. This impact is not considered significant since each
receiver site has unaffected shoreline nearby and recolonization of the receiver site would be rapid. The
closest nest sites of the threatened western snowy plover are approximately 500 feet at Batiquitos, although
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the nest location is north of the inlet jetty and the receiver site is south. Other sites are to five miles from
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the proposed receiver sites. The two closest sites (Batiquitos and Cardiff) are characterized by high human
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use (which make them less attractive for foraging). Additionally, the Cardiff site has cobble, not sand.
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However, concern has been expressed by the USFWS that beach building activity at the Batiquitos site
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during nesting season may result in indirect impacts to this species. SANDAG has initiated consultation
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with the USFWS and USACOE under Section 7 of the Endangered Species Act to ensure potential
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construction impacts are reduced. This could involve scheduling receiver site construction as early in
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nesting season as possible for particular sites (i.e., Batiquitos) or completion of selected sites prior to
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nesting season. SANDAG will conform to the negotiated agreement reached during the Section 7 process
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to avoid significant impacts to the shorebird.
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Some temporary attraction of birds (particularly scavengers such as gulls) to the discharge location to feed
on dead invertebrates and organic matter is anticipated based on observations ofother beach replenishment
projects.
Turbidity. Turbidity has the potential to indirectly impact plankton, fish, marine mammals, birds, vegetated
reefs, and benthic invertebrates. As discussed in Section 4.3, turbidity would be expected to be localized
to the discharge location (average 250 feet) under average current conditions, and could extend up to
1,000 to 3,000 feet downcurrent under maximum current speeds at some sites. Plumes would be expected
to be within 1,000 feet from shore. Further, concentrations within the plume would be expected to be no
higher than that which occurs naturally in nearshore waters under higher wave or storm conditions, and with
implementation of longitudinal dikes, would be even less.
Regional Beach Sand Project EIR/EA
Page 4.4-17
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