Colorado Attorney General Phil Weiser this week vowed to legally challenge a newly published federal rule the Trump administration created to replace an Obama administration rule governing protection of waters under the Clean Water Act.

The Environmental Protection Agency and Army Corps of Engineers published the new rule Tuesday in the Federal Register, after announcing its components in January. It takes effect June 22.

Much of the ongoing dispute surrounds how “waters of the United States” are defined in implementing the Clean Water Act.

The Trump administration says its new rule applies to territorial seas and traditional navigable waters, perennial and intermittent tributaries to those waters, wetlands adjacent to waters falling under the rule’s jurisdiction, and some lakes, ponds and impoundments. Groundwater, ephemeral streams that flow only due to rainfall, many ditches and prior converted cropland are among waters exempted from the rule.

Weiser and the administration of fellow Democrat Gov. Jared Polis don’t totally oppose the new rule, praising its agricultural exemptions and saying it recognizes state authority.

“However, the federal government’s decision to remove from federal oversight ephemeral waters, certain intermittent streams, and many wetlands is based on flawed legal reasoning and lacks a scientific basis,” Weiser said in a new release. “We are going to take legal action to protect Colorado waters and prevent the harmful aspects of the final rule from taking effect here.”

The Colorado Department of Public Health and Environment says the rule eliminates many federal protections and almost 70% of Colorado waters could be impacted by the rule.

Patrick Pfaltzgraff, the director of the state deparment’s Water Quality Control Division, has said the division would do everything possible to protect streams and wetlands in the absence of federal leadership.