ABSTRACT
In 1972 the U.S. Congress passed Public Law (PL) 92-500, the Federal Water Pollution Control Act Amendments of 1972 (the “Act” or “CWA”). Section 316(b) of the Act addressed cooling-water intake structures (CWIS). This section required that “… the location, design, construction, and capacity of cooling water intake structures reflect the best technology available for minimizing adverse environmental impact (AEI).” Despite the passage of nearly 30 years, scientists, regulators, and resource managers have yet to reach a consensus on what constitutes AEI[1]. This lack of consensus is reflected in the title of this Symposium, “Defining and Assessing Adverse Environmental Impact.” Based on the titles of their papers, more than half the authors at this symposium attempted to define what level of organization (individual, population, or community) was appropriate to assess AEI or how AEI should be measured at the chosen organizational level. Thus, in their titles there are words or phrases like “defining and assessing AEI”[2], “indicators of AEI”[3], “the challenge of defining endpoints”[4], and “defining AEI”[5]. As part of a 1995 Consent Agreement, the U.S. EPA is revising Section 316(b) of the CWA. In the final rule for New Sources intakes, signed 9 November 2001, the EPA did not define AEI. Because no definition has been established, the debate over AEI continues, in part because the context for such a definition involves societal as well as scientific considerations[6]. Indeed, one of the more contentious debates during public meetings held in conjunction with promulgating the new 316(b) rules has been how to determine what level of organization to assess. One faction believes that in a societal context, the loss of even one individual (the “one dead fish” position) is unacceptable, while many scientists believe that assessment must be at a higher level of organization (population or community). Given the chasm that exists between these two positions, the EPA will have to display Solomon-like wisdom to appease all parties. Interpretation of AEI is particularly important to the electric utility industry because of the volume of cooling water they use and, at least, the potential to affect fish populations adversely. Historically, the EPA consistently made decisions regarding 316(b) compliance on a site-specific basis, relying on information provided as part of 316(b) “Demonstrations.” However, for new sources, the EPA has recently established generic guidelines that apply regardless of the waterbody type (e.g., rivers and streams vs. lakes and reservoirs) on which the CWIS is located. This generic approach makes it even more difficult to define AEI since populations and communities vary from site to site. A final complication is that roughly half of the U.S.’s electric generation capacity is located on large rivers (unpublished EPRI data), but the EPA has no guidance document describing how to assess biological populations or communities in large rivers. Because of this lack of guidance, the EPA has decided against using biological criteria as part of the 316(b) assessment process. Thus, even if agreement is reached on what constitutes AEI, there are currently no standard protocols to measure and assess
endpoints on the waterbody type that contains the highest percentage of the nation’s generating capacity.
