Water is an important part of power plant operation. In 2015, EPA promulgated three new water-related regulatory programs that have the potential to impact APS.

Rule 316(b) Cooling Water Intake Structures

This rule establishes standards to protect fish and other aquatic organisms from the impact of cooling water intake structures. For APS, Rule 316(b) only applies to the Four Corners Power Plant. APS is initiating conservation measures that will meet the requirements of the rule.

Effluent Limitation Guidelines (ELG) Rule

This rule regulates wastewater discharges from fly and bottom ash handling, flue gas desulfurization (FGD) operations and non-chemical metal cleaning wastes. At Four Corners, discharge of bottom ash transfer water must cease by a date to be identified in the National Pollution Discharge Elimination System (NPDES) permit by EPA. APS continues to work on engineering solutions to meet these requirements.

Waters of the United States

In 2015, EPA revised the definition of Waters of the United States (WOTUS) under the Clean Water Act. On March 6, 2017, EPA and the Army Corps of Engineers released a notice of intent to review and rescind or revise the WOTUS rule. It is unclear at this time what the new WOTUS rule will look like; however, APS remains well positioned for compliance under either of the prior WOTUS definitions. APS will continue to track this rulemaking as it develops.