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/