Effects of Thermal Discharge from the
San Onofre Nuclear Generating Station
JOSEPH N. REEVES, Mechanical Engineer
Southern California Edison Company
Los Angeles, California
INTRODUCTION
Since the summer of 1963, the Southern California Edison Company and The
San Diego Gas and Electric Company have been conducting an extensive oceano-
graphic monitoring program of the marine environment offshore of the San Onofre
Nuclear Generating Station. This work has been conducted in compliance with the
San Diego Regional Water Quality Control Board, which has established the discharge
requirements for the San Onofre station. Bendix Marine Advisers, Inc., of Solana
Beach, California, acting as consultant to the Companies, has performed all field
observations and data analysis for the entire seven years of study.
The purpose of the monitoring program has been twofold: 1) to quantitatively
and qualitatively describe all important features of the ocean environment prior to
plant operation; and 2) to evaluate any effect which the plant might have on the
marine biological community after plant operation begins. In order to adequately
assess the impact of plant operation on the environment, the monitoring program has
continued well into the operational period of the plant, currently two and one half
years since start up in late 1967. A report (1) summarizing the major results of the
pre and postoperational periods was submitted to the Regional Water Quality Control Board in November, 1969. The report concludes that no significant adverse
effects on the general marine environment have been observed which can be associated with the operation of the San Onofre station.
LOCATION
The San Onofre Nuclear Generating Station is located in Southern California,
approximately five miles south of the city of San Clemente, on a coastal marine
terrace adjacent to the Pacific Ocean. The station currently produces 450,000 kilowatts of electrical power, or enough to supply the needs of approximately one half
mil people. The plant site, which is within the boundary of the Camp Pendleton
Marine Corps Base, is considered ideally suited for nuclear power generation since the
surrounding area is sparsely populated due to the natural exclusion provided by the
Marine Base, while at the same time ready access exists to an adequate source of
condenser cooling water and to necessary highway and railroad transportation facilities.
The topography surrounding the site consists of a gentle sloping coastal plain
terminated abruptly at the shore line by straight seacliffs approximately 80 ft high.
At the base of the cliffs is a narrow strip of beach which alternately disappears and
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