Regulatory Update   |   Jun 2nd, 2014 EPA Signs 316(b) Final Rule – Time for Action


On May 19, 2014 the U.S. Environmental Protection Agency (EPA) issued the 316(b) final Rule addressing cooling water intake structure impacts at certain existing electrical generation and manufacturing facilities.

At first glance, the final Rule presents an added level of complexity when compared to the proposed Rule issued in March 2011. However, with proper planning and management, it offers additional flexibility for achieving and demonstrating compliance, which could result in substantial savings.

The 316(b) Final Rule

Section 316(b) of the Clean Water Act (CWA) requires that the location, design, construction, and capacity of cooling water intake structures reflect the Best Technology Available (BTA) for minimizing adverse environmental impact.

The 316(b) final Rule retained many aspects of the proposed Rule, including extending regulatory provisions to power generating, manufacturing and industrial facilities that withdraw 2 mgd and use at least 25 percent for cooling purposes. The entrainment provisions of the final Rule are also similar to those of the proposed Rule, promoting establishment of site-specific, entrainment mortality (EM) requirements at all facilities on a best professional judgment (BPJ) basis, but imposing additional EM-related study requirements to facilities with average intake flows greater than 125 mgd.

The most notable difference is that the final Rule replaces the two impingement mortality (IM) compliance options of the proposed Rule with an expanded list of seven compliance alternatives:

  1. Operate a closed-cycle recirculating system (i.e., cooling towers);
  2. Operate a cooling water intake structure that has a maximum through-screen design intake velocity of 0.5 fps;
  3. Operate a cooling water intake structure that has a maximum through-screen intake velocity of 0.5 fps;
  4. Operate an offshore velocity cap that is installed before [the effective date of rule; TBD];
  5. Operate a modified traveling screen that the Director determines meets the definition at § 125.92(s) and that the Director determines is the best technology available for impingement reduction;
  6. Operate any other combination of technologies, management practices and operational measures that the Director determines is the best technology available for impingement reduction; or
  7. Achieve the specified impingement mortality performance standard.

Alternatives 1, 2 and 4 are referred to by EPA as “essentially pre-approved technologies requiring no demonstration or only a minimal demonstration that the flow reduction and control measures are functioning as EPA envisioned.” Alternatives 3, 5 and 6 will require more detailed information to demonstrate compliance, which for alternatives 5 and 6, will involve site-specific impingement studies supported by 2 years of biological sampling data. EPA also has modified its definition of “modified travelling screen” to include not only traditional modified Ristroph traveling screens, but also other innovative screen designs that offer similar or better performance relative to the reduction of IM.

Regarding alternative 7, it is important to note that EPA has modified its 12-month average IM from“no more than 12 percent mortality” in the proposed Rule to a less stringent “no more than 24 percent mortality” in the final Rule.

The final Rule also offers a “de minimis rate of impingement” option where facilities can assert that rates of impingement are so low that additional impingement controls are not justified. Permitting authorities, based on a review of site-specific data provided by the facility, may conclude that the documented rate of impingement at the cooling water intake is so low that no additional controls are warranted. In a similar vein, a facility with a low average annual capacity utilization factor (less than 8 percent averaged over a 24-month period) may request less stringent requirements for IM for its intake structure.

The final Rule also presents a definition of “new units at existing facilities” and offers two compliance alternatives for IM and entrainment. Under the new unit standards, a facility must either reduce the average intake flow for the new unit to a level commensurate with closed-cycle cooling; or the facility must demonstrate that it has control measures to reduce the level of adverse environmental impact to a level comparable to that which would be achieved through flow reductions commensurate with the use of a closed-cycle recirculating system.

The first alternative involves installation and operation of cooling towers. The second alternative requires that a facility demonstrate entrainment mortality reductions that are equivalent to 90 percent or greater of the reduction that could be achieved through the first alternative (i.e., 90 percent of that achieved via implementation of closed-cycle cooling).

Implementation Schedule

The schedule and timeline for implementation of the final Rule differs from that presented in the proposed Rule. The final Rule will become effective 60 days after the formal publication of the Rule in the Federal Register. The requirements of the Rule will be implemented in future NPDES permits, as the permits are renewed.

The final Rule still requires submittal of the various permit application §122.21(r) reports/materials, but provides additional flexibility for permits that are scheduled to expire less than 45 months after the effective date of the Rule, allowing such facilities the option to request additional time for submittal. Facilities initiating permitting prior to the effective date of the Rule will be allowed to submit the additional reports/materials as part of their next application. The final Rule also modifies the reporting requirement relative to IM reduction strategies (122.21(r)(6)), requiring that applicants provide details on the “chosen method of compliance with IM standards.”

The Path Forward

EPA estimates 1,065 facilities will be subject to the final Rule, including 544 power generating facilities and 521 industrial/manufacturing facilities.

It is important that facility owners/operators having a cooling water intake structure review the final Rule and evaluate its applicability. All facilities subject to the Rule should review and confirm the configuration and operation of their cooling water intake structures and systems and initiate an assessment of potential options relative to the seven alternatives for complying with the new standards.

Facilities should move forward with compiling previously prepared studies and existing biological studies, evaluate what additional studies and reports may be required, and assess the applicable time frame for developing and submitting this information based on facility-specific permit status.

What are your 316(6) compliance challenges? Do you have a permitting strategy in place? Please share your questions, concerns, experiences and best practices in the comments section below.