To know what to expect it is my understanding that deceased SCOTUS Justice Antonin Scalia Plurality Opinion in Rapanos VS United States is what the current administration feels should be the limitation for guidance.

"The plurality opinion stated that the Clean Water Act confers federal jurisdiction over non-navigable waters only if the waters exhibit a relatively permanent flow, such as a river, lake, or stream. In addition, a wetland falls within the Corps' jurisdiction only if there is a continuous surface water connection between it and a relatively permanent waterbody, and it is difficult to determine where the waterbody ends and the wetland begins."