As far as fighting rollbacks in environmental protection, my philosophy is "Never give an inch!" I will most certainly give the soulless profiteers of environmental rape the 2+ inches of my middle finger, though!
Basically, under the proposed new rule, if you dump pollutants into a stream that runs year-round, the federal government has jurisdiction. But, if you dump the same pollutants into a stream that occasionally dries up*, there's not a damn thing the federal government can do about it.
So, if I have a bunch of leaking chemical drums on my property, and those chemicals run into, say, the Skagit and kill off most of the remaining steelhead, whether I'm held accountable will depend on how the pollutants got there. That wasn't the case under the currently existing rule: the current rule recognizes that everything runs downstream.
*It's a bit more nuanced than that, under the proposed rule there would be "intermittent" streams and "ephemeral" streams, the difference being why they occasionally dry up. This distinction does not exist under the current rule. I do not envy the private landowners who, if this proposed rule takes effect, are going to have to sort out whether the waterways on their properties are intermittent or ephemeral--this is going to create a lot of uncertainty and confusion.
Most of the comments seem consistent with the agencies' own analysis in the draft NPRM:
[N]arrowing the scope of CWA regulatory jurisdiction over waters may result in a reduction in the ecosystem services provided by some waters, and as a result, some entities may be adversely impacted. Some business sectors that depend on habitat, such as those catering to hunters or anglers, or that require water treatment to meet production needs, could experience a greater impact relative to other sectors.