The Trump administration has taken aim at removing environmental federal protections for wetlands and isolated streams from pollution.
The Environmental Protection Agency unveiled a proposal redefining US waters under the Clean Water Act.
Farm and agriculture lobbyists have pushed for these changes since 2015.
But environmentalists say they could result in contaminating millions of acres of waters with pesticides and other agricultural pollutants.
What’s in the proposal?
The proposal seeks to remove protections on "ephemeral streams" – which only appear after rainfall – and wetlands not directly connected or adjacent to large bodies of water.
The replacement regulation would not change protections for large bodies of water and neighbouring wetlands, and any state-imposed rules will also be unaffected.
The changes would replace an Obama-era regulation, but the wetland protections impacted date back to the George HW Bush administration.
Announcing the proposal on Tuesday, Environmental Protection Agency Acting Administrator Andrew Wheeler described it as "an end to the previous administration’s power grab".
Mr Wheeler said the changes clarified what waters the federal government had jurisdiction over while respecting "the primary role of the states" in managing environmental […]