EVEREST June, 2013 - California Department of Boating and ...

Orange County Coastal Regional Sediment Management Plan
• Removal and/or damage to sensitive habitats and/or resources from equipment
operation (dredges, pipelines vehicles, vessels), sand placement, or sand removal;
• Disturbance and/or interference with movement, foraging, and/or reproduction of
sensitive species from equipment operation (noise, disturbance); and
• Persistent turbidity or water quality changes that interfere with foraging, respiration,
recruitment, or reproduction of sensitive species or degrade vegetated habitats.
• Potential for release of contaminants and adverse effects on aquatic animals.
After sand placement or removal, the primary indirect impact relates to the recovery rate of
invertebrates, which represent important forage for fish and birds. Important considerations of
recovery rates include the relative change in sediment and habitat quality relative to existing
conditions and project timing. Invertebrates seasonally recruit to beaches; therefore, recovery
may be promoted by conducting projects outside the spring-summer peak productivity period.
Recovery of subtidal invertebrate assemblage may be promoted by minimizing changes in
sediment, hydrodynamics, or water quality within dredged areas (SAIC, 2011b).
The primary indirect impact concern of sand migration from the receiver site is the potential to
degrade sensitive habitats, if nearby. Impacts of potential concern after construction include:
• Alteration of sediment, hydrodynamics, or habitat quality that delays invertebrate
recovery rates;
• Turbidity, sedimentation or sand migration that degrades nearshore reefs or vegetated
habitats of particular concern (HAPCs);
• Sand migration that increases the frequency or volume of maintenance dredging or
excavation in nearby bays, creeks, or harbors.
Cumulative effects are the "impact on the environment that results from the incremental impact
of the action when added to other past, present, and reasonably foreseeable future actions ...”
(40 Code of Federal Regulations 1508.7). The area of potential effect may occur in the Plan
area over time due to repeated effects from an action in the same area, additive effects from
multiple impact sources, or a combination of effects taking place slowly over time (Peterson and
Bishop, 2005).
RSM planning provides opportunity to increase the regional effectiveness of beneficial use of
maintenance dredged materials, opportunistic upland sand sources, and offshore dredging and
beach nourishment projects. Because RSM activities involve repetitive beach nourishment and
dredging in certain areas, the potential for cumulative impacts is an anticipated issue of
concern. Avoidance of repetitive disturbance within the same Plan area within the same year is
recommended to promote recovery of the invertebrate prey base and minimize cumulative
impacts.
Establishing a geospatial database to track projects, sediment quantities, and frequency of
implementation would facilitate assessment of potential cumulative impacts on the basis of both
geographical (e.g., percentage of planning area affected) and temporal (frequency) scales of
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