Facilities that use cooling water intake structures to withdraw water from the waters of the United States and have or require an NPDES permit, take note: the Environmental Protection Agency issued its final rule on cooling intakes for existing electric generating plants and factories in May. EPA finalized the standards under the Clean Water Act to follow through on a settlement agreement with environmental groups.

For those not familiar with the cooling water intake rule, Section 316(b) of the Clean Water Act requires EPA to issue regulations on the design and operation of intake structures in order to minimize adverse environmental impacts on fish, shellfish and their eggs. EPA promulgated regulations in 2001, 2003, 2006 and 2014, and the requirements are included in the NPDES permit regulations, 40 CFR Parts 122 and 125 (Subparts I, J, and N). Facilities affected by the regulations are required to design and operate their intake structures to minimize adverse environmental impacts.

While many industrial sectors are affected, electric generating plants, pulp and paper mills, chemical manufacturing plants, iron and steel manufacturing, petroleum refineries, food processing facilities and aluminum manufacturing plants are among the largest groups, according to the EPA. Fortunately, the technologies required under the rule are well understood, have been in use for several decades, and are in use at more than 40 percent of facilities.

Though the EPA tailored the rule toward the protection of fish and shellfish, aquatic organisms such as manatees and sea turtles are also impacted by impingement, entrainment and entrapment. (The affected aquatic life lacks the means to escape the cooling water intake and is drawn into the cooling water intake structure and cooling water system, or trapped against a screening device.) The full rule offers specific insights for particular species and demonstrates how starting with a baseline level of protection followed by site-specific analysis can help identify the best technology available to reduce impingement mortality.


Linda Becker, Associate Publisher and Editor,