3.4 Biological Resources
Receiver Sites
3.4.3
Intertidal habitats at proposed receiver sites were mapped between May and July 1999 and January
through March 2000. Extensive habitat mapping was conducted by the U.S. Navy in 1997 and focused
subtidal surveys were conducted in January and March 2000. Rocky substrate areas mapped in
1999/2000 corresponded well to 1997 map information.
The proximity of the receiver sites to reefs and/or kelp beds located further offshore was considered for
each site because the project has the potential to result in impacts associated with increased turbidity and
sediment transport. Historical maps of nearshore resources, additional map information provided by
commercial fishermen, and representative photographs of the receiver sites are provided in Appendix D.
The receiver sites are characterized by varying combinations of sand and cobble. Receiver sites at South
Oceanside, Del Mar, and Mission Beach are almost entirely sand habitats. Sand habitat is inhabited by
worms, sand crabs, crustaceans, and bean clams. Other sites have hard substrate in the form of cobbles,
rock revetment, rock, or sandstone bench with various resource development. The Cardiff, Torrey Pines,
and Imperial Beach receiver sites are predominantly cobble. Sites in Carlsbad, elsewhere in Encinitas, and
Solana Beach have sand plus cobble bands of varying widths and density. Each of the 13 receiver sites
is described below in terms of species and habitat identified within the receiver sites boundaries (i.e.,
footprint) and nearby sensitive resources. Sensitive resources are defined at the habitat level to include
vegetated nearshore reefs and kelp beds, and at the species level to include protected, and/or threatened
and endangered species. The types of habitats observed and expected at the receiver sites and nearshore
in the vicinity are summarized in Table 3.4-1. This table reflects data from past Navy analyses (1995,
1997a, 1997b), field work in 1999 and 2000, and input from local commercial fisherman.
Nearshore habitats adjacent to the beach replenishment sites support invertebrates, fish, algae, surfgrass,
kelp, mammals, and foraging birds. Communities of invertebrates and fish that inhabit the nearshore areas
are determined by the type of bottom substrate (sandy or hard-substrate) and the presence of kelp or
surfgrass. Nearshore habitats adjacent to the receiver sites are sandy bottom, with varying amounts of hard
substrate at several of the sites. Hard substrate with surfgrass or kelp occur offshore several of the sites.
Vegetated areas are functional habitats, supporting associated fishes and invertebrates.
Page 3.4-14
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