Clean Water Act: EPA's Final Rule for Cooling Water Intake Structures At Utility And Manufacturing Facilities

On May 19, the U.S. Environmental Protection Agency (EPA) concluded nearly 20 years of effort to adopt rules under Section 316(b) of the Clean Water Act governing the use of cooling water at power plants and industrial facilities. The EPA's final regulations establish requirements for cooling water intake structures (CWISs) at existing facilities (the Final Rule).

Section 316(b) requires that the location, design, construction and capacity of CWISs reflect the best technology available (BTA) for minimizing adverse environmental impacts. According to the EPA, the Final Rule will affect approximately 1,065 existing facilities, including 544 electric generators and 509 manufacturers. The Final Rule will be effective 60 days after publication in the Federal Register.

The Final Rule applies to existing facilities that withdraw more than 2 million gallons per day of water from the waters of the United States and that use at least 25 percent of this water exclusively for equipment cooling purposes. The EPA states that the Final Rule addresses site-specific challenges and "establishes a common sense framework, putting a premium on public input and flexibility for facilities to comply." The 559-page Final Rule is accompanied by a 339-page biological opinion from the U.S. Fish and Wildlife Service. The Final Rule's requirements address the potential adverse environmental impacts ? impingement and entrainment ? associated with the use of CWISs at existing facilities.

The Final Rule requires a permittee to select one of seven options to meet BTA for reducing impingement mortality. Impingement mortality occurs as aquatic organisms in cooling water meet a facility's intake screens.

The Final Rule sets forth a national BTA standard for reducing entrainment. Entrainment occurs when aquatic organisms are drawn through a facility's cooling water system. The national standard is a process for conducting a site-specific determination of entrainment mitigation requirements at existing CWISs. The EPA's assessment is that there is no single technology that is the BTA for entrainment at existing facilities. Instead the site-specific determination process takes into consideration a number of factors. Site-specific decision-making could lead to a determination by the EPA or by a state permitting authority that entrainment reduction requirements should be based on the incorporation of variable speed pumps, water reuse, fine mesh screens, a closed-cycle recirculating...