Cooling water intake rules final

Jan. 24, 2002
EPA has finalized its rule on cooling water intake structures for new facilities. The new rule implementing section 316(b) of the Clean Water Act (CWA) became effective Jan. 17, 2002.

Jan. 24, 2002 -- EPA has finalized its rule on cooling water intake structures for new facilities. The new rule implementing section 316(b) of the Clean Water Act (CWA) became effective Jan. 17, 2002. The rule also partially fulfills EPA's obligation to comply with a consent decree resulting from the case of Riverkeeper Inc., et al. v. Whitman.

The rule can be found at 40 CFR Parts 9, 122, 123, 124, and 125, and it applies to new facilities that use water withdrawn from rivers, streams, lakes, reservoirs, estuaries, oceans or other waters of the United States for cooling purposes.

The rule governs the design, capacity, and construction of new structures at an estimated 121 new manufacturing and electric generating plants over the next 20 years. The rule, along with two more rules scheduled over the next three years, are required by the Clean Water Act.

EPA called the technology-based requirements flexible, saying that "Sources are not required to use certain technologies, but can innovate and adapt based on local circumstances."

EPA estimates the cost to implement the rule will be less than $47 million annually, with no impact on the nation's energy supply. The rule and additional information is available at:, under "What's New," or see the federal register online at

New facilities subject to this regulation include those that have or are required to have an NPDES permit because they discharge or might discharge pollutants, including storm water, from a point source to waters of the United States and that have a design intake flow of greater than two million gallons per day (MGD) and that use at least 25 percent of water withdrawn for cooling purposes. Generally, facilities that meet these criteria fall into two major groups: new steam electric generating facilities and new manufacturing facilities.

If a new facility does not meet the two MGD intake flow threshold or uses less than 25 percent of its water for cooling water purposes, the permit authority will implement section 316(b) on a case-by-case basis, using "best professional judgment."

The final rule establishes performance requirements for the location, design, construction, and capacity of cooling water intake structures at new facilities based on a two-track approach.

Track I establishes national intake capacity and velocity requirements as well as location- and capacity-based requirements to reduce intake flow below certain proportions of certain waterbodies (referred to as "proportional-flow requirements"). It also requires the permit applicant to select and implement design and construction technologies under certain conditions to minimize impingement mortality and entrainment. Under Track I, new facilities with a design intake flow equal to or greater than 2 MGD, but less than 10 MGD, must have through-screen intake velocity less than or equal to 0.5 feet per second, and meet location- and capacity-based limits on proportional intake flow.

Track II allows permit applicants to conduct site-specific studies to demonstrate to the Director that alternatives to the Track I requirements will reduce impingement mortality and entrainment for all life stages of fish and shellfish to a level of reduction comparable to the level the facility would achieve at the cooling water intake structure if it met the Track I requirements.

This final rule defines the term "cooling water intake structure" to mean the total physical structure and any associated constructed waterways used to withdraw water from a water of the U.S. The cooling water intake structure extends from the point at which water is withdrawn from the surface water source up to and including the intake pumps.

EPA does not intend that the new rule or preamble serve as guidance for developing requirements for existing facilities. It says that permit writers should continue to apply best professional judgment in making case-by-case decisions.

EPA amended the definition of cooling water to ensure that the rule does not discourage the reuse of cooling water as process water. As such, heated cooling water that is subsequently used in a manufacturing process is considered process water for the purposes of calculating the percentage of a new facility's intake flow that is used for cooling purposes.

EPA said it did not intend to change the regulatory status of cooling ponds. Cooling ponds are neither categorically included nor categorically excluded from the definition of "waters of the United States" at 40 CFR 122.2. EPA interprets 40 CFR 122.2 to give permit writers discretion to regulate cooling ponds as "waters of the United States" where cooling ponds meet the definition.' The determination whether a particular cooling pond is or is not "waters of the United States" is to be made by the permit writer on a case-by-case basis, informed by the principles enunciated in Solid Waste Agency of Northern Cook County v. US Army Corps of Engineers, 531 U.S. 159 (2001).