DISCUSSION: Southern California Edison Company (SCE) owns and operates the SONGS power plant located on the Pacific Coast in northern San Diego County. The plant consists of two twin generating units (Units 2 and 3; an older Unit 1 is no longer in operation) with separate cooling systems. The two active units employ once-through cooling water systems, withdrawing cooling water from the Pacific Ocean and discharging it to the ocean through separate underwater diffusers situated on the ocean bottom approximately ½ to 1½ miles offshore. Each underwater diffuser is 762 meters long, with 63 diffuser ports. The Unit 2 diffuser ends 2500 meters from shore in approximately 15 meters of water. The Unit 3 diffuser ends 1800 meters from shore in approximately 12 meters of water. The diffusers are placed such that sensitive near shore marine habitat, especially intertidal and shallow subtidal habitat, will not be affected by heat from the discharge. The two units have operated since the mid-1980s under separate discharge permits issued by the San Diego Regional Water Quality Control Board (SDRWQCB). Each is rated at approximately 1180 megawatts and discharges approximately 1,200 million gallons of heated sea water per day.

The SONGS discharges are subject to the Thermal Plan with respect to the thermal component of the discharge. As required by the Thermal Plan, the SONGS discharge permits specify that the effluent from Units 2 and 3 may not exceed the receiving water temperature by more that 20° F. (This temperature difference is generally referred to as DT--"delta T".) SONGS has operated with this limitation since Units 2 and 3 began operations in the early 1980s. (For practical reasons, DT is not measured in the receiving water but across the condensers within the SONGS cooling system. DT is taken to be the difference in temperature of the cooling water before and after it has been heated by passing through the heat exchanger/condenser structures.)

In 1997, SCE, claiming that a general loss of efficiency of the SONGS cooling system over the years had reduced the plant's ability to generate full rated power while complying with the 20° F DT limitation, asked SDRWQCB for an exception to the SONGS discharge permits to raise the discharge DT to 25°F. This higher limitation, according to SCE, would allow the two SONGS units to again generate their rated power, particularly during the summer when the impacts of the system's deterioration have placed greatest constraints on power production.

The Thermal Plan specifies that a Regional Water Quality Control Board (RWQCB) may grant an exception to specific water quality objectives of the Thermal Plan in accordance with Section 316(a) of the Federal Clean Water Act (CWA). Any exceptions granted by an RWQCB must receive the concurrence of the State Water Resources Control Board (SWRCB) before becoming effective. On February 11, 1998, after conducting and publishing a California Environmental Quality Act (CEQA) Initial Study of the requested exception, and following a public hearing, SDRWQCB approved the exceptions for the two SONGS permits as requested and adopted a CEQA Negative Declaration on its action. The issue is now being presented to SWRCB for concurrence.

The requirements to be met by an applicant for an exception to thermal discharge limitations and by a state considering granting such an exception are given in CWA Section 316(a) and associated regulations, particularly 40 Code of Federal Regulations PART 125, Subpart H. Under Section 316(a), the applicant has the opportunity to demonstrate to the satisfaction of the State that the proposed exception, considering the cumulative impact of the thermal discharge taken together with all other significant impacts on the species affected, will assure the protection and propagation of a balanced indigenous population of shellfish, fish, and wildlife in the affected water body. Based on the applicant's demonstration, the State may then grant such an exception. Any exception granted under Section 316(a) must be reviewed at the time of permit renewal (every five years in this case).

Title 40 Code of Federal Regulations section 125.73 (c) provide as follows:

"(c)(1) Existing dischargers may base their demonstration upon the absence of prior appreciable harm in lieu of predictive studies. Any such demonstration shall show:

"(i) That no appreciable harm has resulted from the normal component of the discharge taking into account the interaction of such thermal component with other pollutants and the additive effect of other thermal sources to a balanced indigenous community of shellfish, fish and wildlife in and on the body of water into which the discharge has been made; or

"(ii) That despite the occurrence of such previous harm, the desired alternative effluent limitations (or appropriate modifications thereof) will nevertheless assure the protection and propagation of a balanced, indigenous community of shellfish, fish and wildlife in and on the body of water into which the discharge is made.

Title 40 Code of Federal Regulations section 125.71(c) defines a balanced indigenous community or population as follows:

"a biotic community typically characterized by diversity, the capacity to sustain itself through cyclic seasonal changes, presence of necessary food chain species and by lack of domination by pollution tolerant species .... Normally, however, such a community will not include species whose presence or abundance is attributable to the introduction of pollutants that will be eliminated by compliance by all sources with section 301(b)(2) of the (Clean Water ) Act (technology based effluent limits); and may not include species whose presence or abundance is attributable to alternative effluent limitations imposed pursuant to section 316(a)."

A number of studies have been done to assess the impacts of the SONGS discharge and cooling water intake systems. The California Coastal Commission (CCC), in accordance with its permitting authority, established a Marine Review Committee (MRC) in 1974 to oversee biological studies related to the operation of SONGS. The MRC concluded its work in 1989, and identified substantial biological impacts from the operation of SONGS. MRC determined that the identified impacts were caused mainly by entrainment of organisms in the cooling water intakes and by discharge-induced turbidity. MRC found "negligible thermal effects" from the SONGS discharge. MRC alleged that SONGS was not in compliance with two provisions of its discharge permits, in that it caused: (1) reduction of natural light levels and (2) adverse impacts (population reductions) on certain marine organisms.

In 1991 and 1992, SDRWQCB held hearings on the question of whether SONGS had violated its discharge permit, as alleged in the MRC Report. After considering all the evidence presented, which included studies disputing the MRC conclusions, SDRWQCB determined in February 1992 that MRC's allegations of permit violations were not convincing and, therefore, did not find SONGS to be in violation of its permit.

On the basis of the MRC study CCC imposed new permit requirements on SONGS to mitigate the adverse biological impacts of the SONGS discharge and cooling water intake system. The required mitigation includes restoration of wetlands, construction of an offshore reef as new kelp habitat, installation of behavior barriers on the intake structure to reduce fish entrainment, and partial financing of a fish hatchery. CCC recently estimated the cost of the required mitigation to be approximately $117 million.

In June 1994, under contract with the U.S. Environmental Protection Agency, Science Applications International Corporation (SAIC) issued a report entitled "Review of Southern California Edison, San Onofre Nuclear Generating Station (SONGS) 316(b) Demonstration. Review under CWA 316(b) is required to determine that the location, design, construction, and capacity of cooling water intake structures reflect the best technology available for minimizing adverse environment impact. This study considered the MRC study and other information about the effects of SONGS on the marine environment. The SAIC study concluded that adverse impacts have resulted from the operation of SONGS, but nevertheless that the features of a balanced indigenous community existed in the vicinity of the SONGS discharge and intake structures.

SWRCB staff has reviewed the record of this action submitted by SDRWQCB and has concluded that Southern California Edison has made the demonstration required by 40 Code of Federal Regulations section 125.73(c)(ii), that despite any occurrence of previous harm, the desired alternative effluent limitations will assure the protection and propagation of a balanced, indigenous marine community.

Staff therefore recommends that the SWRCB approve the exception provided in the Thermal Plan and permit an increase of 5° F for the SONGS discharges.

This recommendation is made with the consideration that while there is evidence of marine impacts from SONGS caused by entrainment and discharge-induced turbidity, there is no evidence of adverse impacts caused by the thermal component of the discharge. A conclusion that effects due to the proposed increase in temperature will be minimal is supported by the location and design of the outfall's diffusers as noted above. The discharge, located on an open coastal stretch where both natural ocean currents and the flow design of the discharge structure contribute to rapid diffusion of waste heat, is diluted and directed such that sensitive near shore marine habitat, especially intertidal and shallow subtidal habitat, will not be affected by heat from the discharge. Additionally, thermal plume modeling of the new discharge conditions as reported in SDRWQCB's Initial Study show clearly that permit requirements will not be violated as a result of the requested permit modification. In short, heat has not been identified by any study as being a significant issue in the SONGS marine environment. Finally, previous impacts to the marine ecosystem caused by other components of the discharge will be addressed by the mitigation measures mandated by CCC. Therefore, protection and maintenance of a balanced indigenous community of shellfish, fish, and wildlife in and on the body of water into which the discharge is made will be assured.

POLICY ISSUE: Should the SWRCB concur in and approve the SDRWQCB action granting amended discharge limitations to SONGS Units 2 and 3. These limitations must be reviewed by SDRWQCB at the time of renewal of the SONGS Units 2 and 3 discharge permits with a view to assuring that balanced indigenous communities of marine life are being maintained in the vicinity of the SONGS discharges.

FISCAL IMPACT: NONE.

RWQCB IMPACT: Yes, SDRWQCB.

STAFF RECOMMENDATION: That the SWRCB concur in and approve the SDRWQCB action granting amended discharge limitations to SONGS Units 2 and 3. These limitations must be reviewed by SDRWQCB at the time of renewal of the SONGS Units 2 and 3 discharge permits with a view to assuring that balanced indigenous communities of marine life are being maintained in the vicinity of the SONGS discharges.

WHEREAS:
1. Southern California Edison Company (SCE) owns and operates the SONGS power plant located on the Pacific Coast in northern San Diego County. SONGS consists of two active units, each discharging approximately 1,200 million gallons per day of heated sea water to the Pacific Ocean. The two active units employ once-through cooling water systems, withdrawing cooling water from the Pacific Ocean and discharging it to the ocean through separate underwater diffusers situated on the ocean bottom approximately ½ to 1½ miles offshore. Each underwater diffuser is 762 meters long, with 63 diffuser ports. The Unit 2 diffuser ends 2500 meters from shore in approximately 15 meters of water. The Unit 3 diffuser ends 1800 meters from shore in approximately 12 meters of water. The diffusers are placed such that sensitive near shore marine habitat, especially intertidal and shallow subtidal habitat, will not be affected by heat from the discharge.
2. The SONGS discharges operate under separate discharge permits issued by the
San Diego Regional Water Quality Control Board (SDRWQCB) and are subject to the Thermal Plan with respect to the thermal component of the discharges. SONGS has complied with the thermal limitations of its discharge permits.
3. The Thermal Plan and the SONGS discharge permits require that the effluent from SONGS Units 2 and 3 may not exceed the receiving water temperature by more than 20°F.
4. The Thermal Plan and the Federal Clean Water Act (CWA) specify that a Regional Water Quality Control Board may grant an exception to specific water quality objectives of the Thermal Plan with concurrence from the State Water Resources Control Board (SWRCB) and in compliance with Section 316(a) of the CWA and associated federal regulations.
5. In May 1997, SCE applied to SDRWQCB for exceptions to the limitation in No. 3 above, so as to allow discharges from Units 2 and 3 to exceed the receiving water temperature by no more than 25° F.
6. CWA Section 316(a) requires an applicant for an exception to thermal discharge limitations to demonstrate that the existing limitations are more stringent than necessary to protect and maintain balanced indigenous communities in the affected water body, taking into account the interaction of such thermal component with other pollutants. Title 40 Federal Code of Regulations section 125.73 requires the applicant for the exception to demonstrate either "that no appreciable harm has resulted" from the discharge, or that "despite the occurrence of such previous harm, the desired alternative effluent limitations will nevertheless assure the protection and propagation of a balanced, indigenous community of shellfish, fish and wildlife in and on the body of water into which the discharge is made."
7. SCE has provided information which demonstrates that the proposed limitation will protect and maintain balanced indigenous communities in the vicinity of the SONGS discharges based on a number of considerations:
a. While there is evidence of impacts caused by entrainment and discharge-induced turbidity, there is no evidence of adverse impacts caused by the thermal component of the discharge.
b. Effects due to the proposed increase in temperature will be minimal because the discharge structures are designed and placed such that sensitive near shore marine habitat, especially intertidal and shallow subtidal habitat, will not be affected by heat from the discharge. Further, thermal plume modeling of the new discharge conditions as reported in SDRWQCB's Initial Study shows clearly that permit requirements will not be violated as a result of the requested permit modification, and that thermal impacts on the sensitive kelp bed environment will be insignificant.
c. Previous impacts to the marine ecosystem caused by other components of the discharge will be addressed by the mitigation measures mandated by the California Coastal Commission.
8. On February 11, 1998, after conducting and publishing a California Environmental Quality Act (CEQA) Initial Study of the requested exception and following a public hearing, SDRWQCB approved the exceptions for the two SONGS permits as requested by SCE. SDRWQCB found that SCE had adequately demonstrated that balanced indigenous communities would be maintained in the vicinity of SONGS if the requested amendment were granted. SDRWQCB adopted a CEQA Negative Declaration on its action.
9. SWRCB staff has reviewed the SDRWQCB action and found that the action complies with State and federal criteria for granting an exception to the Thermal Plan's discharge limitation.
THEREFORE BE IT RESOLVED THAT:
The SWRCB concurs in and approves the SDRWQCB action granting amended discharge limitations to SONGS Units 2 and 3. These limitations must be reviewed by SDRWQCB at the time of renewal of the SONGS Units 2 and 3 discharge permits with a view to assuring that balanced indigenous communities of marine life are being maintained in the vicinity of the SONGS discharges.

Maureen Marché
Administrative Assistant to the Board