4.4 Biological Resources
at distances greater than 1,200 feet from the backbeach. Kelp generally has been absent directly offshore
Agua Hedionda Lagoon.
No long-term, significant impacts to intertidal reefs are expected from this alternative because reef heights
generally are above the maximum persistent sand depths at these locations. Several nearshore reefs with
surfgrass occur in the risk area at the southern end of the receiver site (Figure 4.2-2). At three small reefs
with a total area of 0.24 acre, surfgrass may experience partial sedimentation (less than one foot) such that
short-term impacts to growth could occur; however, because the long leaves would extend well above most
of the predicted deposition, there would be no significant, long-term effect. Nearshore reefs with surfgrass
are also located near Tamarack Avenue (Figure 4.4-18) but shallow depositional depths would not result
in significant impacts at this location.
There is one reef location where giant kelp may, under worst-case conditions, experience partial
sedimentation. A 0.73-acre reef just south of the discharge jetty and north of Cannon Road has a sparse
occurrence of giant kelp and sea fans on the higher relief portions of the reef. This location is within the
inshore limit of giant kelp. Maximum worst-case predicted sand cover would be predominantly well below
reef heights, except at the lower parts of the reef where less than four inches is predicted for up to 1.5
years. Given the sensitivity of kelp to sedimentation, there could be partial impacts at the lower portions
of the reef; however, based on the sparseness of kelp cover and its ephemeral nature at this location, the
impact would be less than significant.
Finally, no long-term impacts to sea fans, sea palms or feather boa kelp are anticipated.
Potential Indirect Impacts Near Batiquitos. Under this alternative, the model predicts sedimentation
risk just south of the lagoon mouth at the Batiquitos receiver site. The nearshore area is cobble with
opportunistic species. No long-term impacts would result since any resources buried would quickly re-
establish. There is a reef complex over 2,000 feet from the back beach at depths greater than -38 feet
MLLW. The complex consists of a larger reef (6.8 acres) that supports sparse amounts of giant kelp,
feather boa and sea fans and a smaller reef (0.5 acre) with sparse kelp (Figure 4.4-4). The reef complex
has heights of zero to 1.5 feet, although most of it is one foot. Furthermore, most of the reef occurs beyond
the depth of closure, which is the seaward limit of normal sand transport. Under worst-case model
predictions, partialsedimentationis indicated for an area of approximately 1.5 acres which is characterized
by sparse giant kelp. Although there maybe some short-term impacts, the overall impact would not be
significant based on the short duration (one and one-half years) of maximum, worst-case predicted
sedimentation and the relatively small amount of reef that would be affected.
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