National Pollutant Discharge Elimination System-Proposed Regulations To Establish Requirements for Cooling Water Intake Structures at Phase III Facilities

Today's proposed rule would establish national categorical requirements under section 316(b) of the Clean Water Act for certain existing facilities that employ a cooling water intake structure and are designed to withdraw water above a certain design intake flow from certain waters of the United States for cooling purposes. Today's notice proposes three possible options for defining which existing facilities would be subject to uniform national requirements, based on design intake flow threshold and source waterbody type: The facility has a total design intake flow of 50 million gallons per day (MGD) or more, and withdraws from any waterbody; the facility has a total design intake flow of 200 MGD or more, and withdraws from any waterbody; or the facility has a total design intake flow of 100 MGD or more and withdraws water specifically from an ocean, estuary, tidal river, or one of the Great Lakes. Because the lowest co-proposed flow threshold option is 50 MGD, the proposed requirements would only apply to manufacturing facilities--as power producers with a flow greater than 50 MGD are regulated under the Phase II rule. This proposed rule would constitute Phase III of EPA's section 316(b) regulation development and would establish national requirements, and procedures for implementing those requirements, applicable to the location, design, construction, and capacity of cooling water intake structures at Phase III facilities. Today's proposed rule would also establish categorical section 316(b) requirements for new offshore oil and gas extraction facilities, which were specifically excluded from the scope of the Phase I new facility rule so that EPA could gather additional data on these facilities. The proposed rule would apply to both existing manufacturers and new offshore oil and gas extraction facilities that withdraw at least 25 percent of the water exclusively for cooling purposes. The proposed national requirements, which would be implemented through National Pollutant Discharge Elimination System (NPDES) permits, are based on the best technology available to minimize the adverse environmental impact associated with the use of cooling water intake structures. For covered existing facilities, today's proposed rule would establish performance standards for reducing impingement mortality by 80 to 95 percent, or impingement mortality by 80 to 95 percent and entrainment by 60 to 90 percent. Today's proposal would allow existing facilities to select from five compliance alternatives consistent with those provided in the final Phase II rule for existing large flow electric power generators. Once finalized and implemented, the rule would minimize the adverse environmental impact of cooling water intake structures by reducing the number of aquatic organisms lost as a result of water withdrawals associated with these structures. Today's proposed rule does not propose to alter the regulatory requirements for facilities subject to the Phase I or Phase II regulations, and EPA is not soliciting comment on those regulations. EPA is only seeking comment on the proposed regulations for Phase III existing facilities and new offshore oil and gas facilities, as reflected in the proposed regulatory text for subparts K and N. Depending on the options selected in the final section 316(b) regulation for Phase III facilities, EPA may decide to integrate the regulatory text for subparts K and N proposed today into the existing subparts I and J, for purposes of streamlining the number of pages for publication.