Evaluating the Effects of Thermal Discharges on Aquatic Life: Patterns in Multimetric Indices from Three Case Studies in Large and Great Rivers of the Midwestern United States
Water is used in many industrial applications to cool machinery and produce condensed steam. The use of water for cooling and its discharge to the environment generally increase downstream water temperatures from electric generating facilities (Majewski and Miller, 1979; Coutant, 1997; Bulleit, 2000). These heated water discharges are regulated by the Clean Water Act, Section 316(a), which prohibits the release of heated water in amounts that would cause adverse effects on aquatic life using the normative standard that is used to judge harm based on the requirement for protection of a balanced indigenous population. The standard has been interpreted as a balanced ecological community of mostly native species (Coutant, 2000). This concept is in agreement with the primary goal of the Clean Water Act: to restore and maintain biological integrity.