Coastal Mitigation Linked to the Effects of the SONGS Cooling Water System (San Onofre Nuclear...
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Transcript of Coastal Mitigation Linked to the Effects of the SONGS Cooling Water System (San Onofre Nuclear...
Coastal Mitigation Linked to the Effects of the SONGS Cooling Water System
(San Onofre Nuclear Generating Station = SONGS)
Unit 3diffuser
Unit 2diffuser
San Onofre kelp forest
Unit 3intake
Unit 2intake
SONGS
Intakes cause substantial reduction in nearshore fish
Discharge causes substantial reduction in San Onofre kelp forest
• Losses of immature fish in the cooling water intake system is projected to cause substantial reductions in populations of adult fish in the S. California Bight
• In-plant losses of juvenile and adult fish led to reductions in the local abundance of mid-water fish populations in near vicinity of SONGS
• The discharge plume caused a substantial reduction in size of the kelp forest community at San Onofre that resulted in losses of kelp, fish, & invertebrates
Adverse Effects Attributed to SONGS Cooling Water System Include:
Condition A: Wetland Mitigation Out-of-kind mitigation to compensate for in-plant losses of
immature fish.
Condition B: Behavioral Barriers Mitigation In-kind mitigation to reduce in-plant losses of juvenile & adult
fish.
Condition C: Kelp Reef Mitigation In-kind mitigation to compensate for losses of kelp and kelp
bed fish and invertebrates.
Condition D: Administrative StructureProvides for scientific oversight and monitoring of mitigation
projects that is independent of SCE.
Mitigation required by the CCC for the impacts caused by SONGS cooling water
system includes four conditions:
Condition A: Wetland MitigationSan Dieguito Lagoon before excavation and grading (2003)
old airfield/ruderal upland
old agricultural fields
ruderal uplandDel Mar Racetrack
San Dieguito River
Freeway
ruderal
agricultural fields
intertidal habitat
Condition A: Wetland MitigationSan Dieguito Lagoon after excavation and grading (2010)
salt marsh
subtidal basin
nesting sites
Del Mar Racetrack
San Dieguito River
I-5Freeway
salt marsh
nesting site
nesting site
disposal site
disposal site
salt marsh
mud flats
Restored wetland now providing habitat for invertebrates, fish, birds & eel grass
Salt Marsh VegetationMonitoring & Adaptive Management
• Salt marsh vegetation is underperforming in some areas.• Monitoring has identified elevation and tidal inundation as the
cause of sparse vegetation.• SCE is planning to re-grade these areas in the coming year to
correct the problem.
March 2013
bare
Condition C: Kelp Reef Mitigation
Artificial Reef(mitigation site)
SONGS
San Clemente
Oceanside
San Mateo(reference site)
Barn(reference site)
N
5 km
Wheeler North Reef constructed in two phases:•Phase1 - 9 hectares (completed October 1999)
•Phase 2- 62 hectares (completed September 2008)
•Phase 1 + Phase 2 = 71 hectare artificial reef
Giant kelpDense surface canopy of giant kelp present on Wheeler North
Reef within 2 years of construction
Summer 2010Image from Landsat 5May 30, 2010
Wheeler North
San Mateo
San Onofre
SONGS
Wheeler North Reef supports populations of algae, invertebrates and fish that are similar to natural
reference reefs
Slide11
Standing stock of kelp bed fish is less than the required 28 tons
Data analysis and discussions with SCE are ongoing to determine the best method for addressing the short fall in fish biomass
Importance of monitoring
Data from independent monitoring are used to determine:
1.whether mitigation is done according to approved plans2.whether the performance standards are met3.the causes for any failures to meet the performance standards4.the most appropriate methods for remediation
1. Provides information that helps guide future restoration efforts2. Develops and refines sampling approaches3. Contributes to an in-depth understanding of the natural history and
ecology of wetland and kelp forest systems
Broader benefits of monitoring
14For more information go to: http://marinemitigation.msi.ucsb.edu/