Proposals concerning large-volume water intakes, such as those for power plants or factories, were issued for public comment by the US Environmental Protection Agency (EPA) on 29 March 2011.
The proposals, to provide standards to protect billions of fish and other aquatic organisms drawn each year into cooling water systems, is based on Section 316(b) of the Clean Water Act and would establish what the EPA calls “a common sense framework”, putting a premium on public input and flexibility.
Safeguards against impingement will be required for all facilities above a minimum size; closed-cycle cooling systems may also require them on a case-by-case basis, when permitting authorities judge them to be appropriate.
Existing facilities that withdraw at least 25% of their water exclusively for cooling purposes and have a design intake flow of greater than 2 MGD (7,750 m³/d) would be required to reduce fish impingement under the proposed regulations. To ensure flexibility, the owner or operator of the facility will be able to choose one of two options for meeting best technology available requirements for reducing impingement.
On fish entrainment, EPA is proposing a site-specific determination to be made based on local concerns and on the unique circumstances of each facility. This proposed rule establishes requirements for the facility owner to conduct comprehensive studies and develop other information as part of the permit application, and then establishes a public process, with opportunity for public input, by which the appropriate technology to reduce entrainment mortality would be implemented at each facility after considering site-specific factors.
Large desalination plants do not appear to be covered by these proposals, which seems to apply only to cooling water.