"The vast majority of Arizona waters now regulated by the state under the federal Clean Water Act could be excluded from protection under the Trump administration’s narrowed definitions of federal waters, according to state environmental officials.

The Arizona Department of Environmental Quality is taking initial steps to launch a state program to oversee waters excluded from the Trump administration’s revised definition of what it considers Waters of the U.S. That definition determines which waters fall under federal oversight.

The Obama administration’s Waters of the U.S., or WOTUS, rule, set a broad definition of which water bodies are and are not eligible for federal anti-pollution protections. The Trump administration rolled that back last month (RIN: 2040-AF74), and wants to define protected waters much more narrowly (RIN: 2040-AF75). "

Brenna Goth reports for Bloomberg Environment November 12, 2019. [2]