Tim Krause and Ken Snell, Sargent & Lundy

On April 9, 2002, the U.S. Environmental Protection Agency (EPA) proposed new regulations for existing cooling water intake structures. The regulations could require significant changes at both nuclear and fossil-fueled power plants with once-through cooling systems. The regulations are commonly known as “316(b) regulations” because they implement Section 316(b) of the Clean Water Act.

The proposed 316(b) regulations apply to power plant cooling water intake structures with the capacity to withdraw 50 million gallons per day or more, which includes most once-through cooling systems. Affected intake structures would have to meet technology-based performance standards. The specific performance standards depend on the cooling water source (freshwater river, tidal river, lake, Great Lake, or ocean), but in general, one of the following would have to be done:

1. Reduce the intake capacity to a level commensurate with the use of a closed-cycle cooling system (e.g., use cooling towers or a cooling pond).
2. Reduce fish and shellfish impingement mortality by at least 80 percent compared with a theoretical intake structure. In some cases, entrainment of fish and shellfish would also have to be reduced. The measures used to achieve these reductions could include technological modifications (e.g., fine mesh screens, fish return systems, barrier nets, etc.), operational modifications (e.g., seasonal shutdowns or reductions in flow), and/or restoration measures (e.g., fish restocking programs, restoring degraded wetlands, etc.).
3. Demonstrate that the costs of complying with 1 or 2 would be significantly greater than the costs EPA estimated in developing the regulations or that the costs are significantly greater than the benefits. The facility would then qualify for a site-specific determination of the best technology available.

Facilities that do not reduce their intake capacity to the level of a closed-cycle cooling system would be required to submit a Comprehensive Demonstration Study. This study would have to describe the cooling water source, establish baseline fish/shellfish impingement/entrainment rates, describe the proposed environmental protection measures and their efficiencies, and propose a monitoring plan to demonstrate compliance. A significant amount of site-specific biological data probably would be needed to support the Comprehensive Demonstration Study.

The 316(b) requirements would be implemented through National Pollutant Discharge Elimination System (NPDES) permits, which are wastewater discharge permits issued by the EPA or authorized state agencies. Normally, the Comprehensive Demonstration Study and other required information would have to be submitted when a facility applies for renewal of its existing NPDES permit. The renewed NPDES permit would then provide a schedule for installing approved environmental protection measures.

Click here to enlarge image

The figure illustrates the major steps required to comply with the proposed 316(b) regulations.

Although the regulations would apply to both nuclear and fossil-fueled power plants, the effects on nuclear plants could be especially significant. Nuclear plants typically require relatively large cooling water flows, so the range of feasible options for reducing the environmental impact of those flows may be restricted. In addition, making physical or operational changes to nuclear plants may involve more complicated regulatory approvals. These factors would have to be carefully considered in developing a compliance strategy.

Another issue that may require careful evaluation is whether a cooling lake is subject to the 316(b) regulations. If a particular cooling lake is considered “waters of the United States”, an intake structure that withdraws 50 million gallons per day from the lake would have to comply with the 316(b) requirements. If, on the other hand, a lake is not “waters of the United States” (for example, if it is considered a wastewater treatment pond), the 316(b) requirements would not apply. The determination of whether any particular lake is “waters of the United States” is made by the NPDES permitting agency on a case-by-case basis.

EPA is under court order to finalize the proposed 316(b) regulations by August 28, 2003. Until then, facilities are not required to do anything to comply. However, depending on when their existing NPDES permits expire, some facilities may have to make decisions and submit information soon after the regulations are finalized. Therefore, it may be advisable to perform preliminary studies, such as the following, before the regulations are finalized:

1. Evaluate the location and capacity of each existing cooling water intake structure and determine which performance standards apply.
2. Collect existing physical and biological data on the cooling water source.
3. Develop engineering calculations and fish/shellfish mortality estimates for a theoretical shoreline intake structure with no impingement or entrainment controls.
4. Use available biological data and design information to determine the existing intake structure’s impingement and entrainment mortality as compared with the theoretical intake structure.
5. If the existing intake structure does not comply with applicable performance standards, identify technically feasible environmental protection measures that could be used to comply.
6. Estimate the capital and operating costs of the identified envi-ronmental protection measures and compare them with the cost and benefit estimates used by EPA in developing the proposed regulations.
7. Determine whether existing physical and biological data for the cooling water source are representative of current conditions and were collected with appropriate quality assurance/quality control.
8. If additional physical/biological data is needed, develop a proposal for field data collection (including a sampling plan and schedule) for submittal to the permitting agency for review and approval.
9. Plan the timing of detailed studies and required submittals based on the plant’s NPDES renewal date.

Studies such as these would allow a facility to determine the optimal compliance strategy based on site-specific conditions.

Tim Krause is an environmental biologist with more than 25 years of experience in the power industry. He currently supervises Sargent & Lundy’s environmental permitting group. He can be reached at 312-269-6616 or at timothy.p.krause@sargentlundy.com.

Ken Snell is an environmental engineer and attorney with Sargent & Lundy and has more than 20 years experience in the fields of environmental compliance, controls and permitting. He can be reached at (312)269-2318 or at kenneth.j.snell@sargentlundy.com.