(h) Entrainment means any life stages of fish and shellfish in the intake water flow entering and passing through a cooling water intake structure and into a cooling water system, including the condenser or heat exchanger. Entrainable organisms include any organisms potentially subject to entrainment. For purposes of this subpart, entrainment excludes those organisms that are collected or retained by a sieve with maximum opening dimension of 0.56 inches. Examples of sieves meeting this definition include but are not limited to a 3/8 inch square mesh, or a 1/2 by 1/4 inch mesh. A facility must use the same mesh size when counting entrainment as is used when counting impingement.
40 CFR § 125.92
In addition to the definitions provided in 40 CFR 122.2, the following special definitions apply to this subpart: