4.2 Coastal Wetlands
COASTAL WETLANDS
4.2
As noted in Sections 2.5 and 3.2, coastal lagoons in the northern part of the San Diego region vary from
having inlets that are always open, intermittently open, or closed to tidal flows. Inlet closures may vary
seasonally from days to several months depending upon lagoon. The main ramification of inlet closure is
a reduction in water quality, which in turn may degrade habitat qualityand result in loss of populations. Inlet
closure also can also promote the development of nuisance species such as mosquitos. The degree of
change to habitats and populations is directly related to the duration of inlet closure. Ongoing maintenance
programs are implemented at most of the region's local lagoons (refer to Table 2-7). Excess sediment is
dredged at some lagoons and at others the inlet is mechanically opened by bulldozer. The evaluation of
potential effects to coastal wetlands is summarized below from the biological resources technical report
(Appendix D) as well as previous Navy analysis (1997a, 1997b).
4.2.1
Impact Significance Criteria
Potential impacts to coastal wetlands would be significant if:
substantial sediment accretion substantially increased the rate of closure above historical occurrences
at any lagoon, river, or creek mouth; or
increased turbidity resulted in adverse affects to the water quality in the water body.
Alternative 1
4.2.2
This analysis focuses on the coastal lagoons and river mouths along the coast that would be located near
the potential receiver sites and is organized by water body, in geographic order from north to south.
Nearby receiver sites are identified as appropriate.
No direct impacts to coastal lagoons would occur from the project, which proposes to dredge sands from
offshore borrow sites and replenish beaches away from lagoon mouths. Any potential impacts would be
related to indirect sedimentation or turbidity. The season of construction, late summer or spring, would not
R
change the conclusions in the analysis.
R
Regional Beach Sand Project EIR/EA
Page 4.2-1
99-69\SANDAG EIREA 4.1 to 4.13.wpd 7/17/00
Previous Page
