On December 1, 2022, the EPA issued an Administrator’s Determination under the Clean Water Act that revised water quality standards (WQS) in certain zones of the Delaware River are necessary to meet the requirements of the Act. Specifically, EPA determined that a designated use that includes propagation and corresponding protective dissolved oxygen criteria are required to protect sensitive aquatic life – including two federally listed species under the Endangered Species Act – in zones 3, 4, and upper-5 of the Delaware River. EPA is now fulfilling its statutory obligation to promulgate the necessary WQS.