Improved Fish Protection at Intake Systems

A chronic and often serious ecological as well as operational problem at cooling water intake systems is the entrainment of fishes in the cooling water. In 1972, Southern California Edison Company (SCE) sponsored joint participation with Ichthyological Associates in studies to develop methods to prevent entrainment at SCE offshore intake structures and to safely remove already entrained specimens from generating station screenwells. Results are presented in detail in Refs. 3 and 4. These studies considered fish behavioral response to levels and changes in velocity and direction of flow as primary design criteria for a generating station cooling water intake system, within the limits imposed by construction and operation restraints. The research was coincident with development of the intake system for the SCE San Onofre Nuclear Generating Station (SONGS), Units 2 and 3. It provided considerations basic to the development of a modified design which is expected to offer greatly increased protection to fishes