There's some Idaho ranchers or something who have a case about what extent of wetlands can be protected by the Clean Water Act. Obama's admin defined it as a much larger area and applied it to seasonal wetlands and the Trump admin scaled it back significantly and said it was basically only areas that were actually wetlands year-round and that the protections didn't extend to the catchment area.

So I expect further limiting of the Feds' power to make sure that water is potable and all the animals don't die.