This is the important sentence in the article.
A sharp path covers much less land, but branching channels are spread out. By arguing that the "natural" state of a river is much broader than the existing channel, much, much more land is brought under control of the "environmental re-mediation".
“She said she and Dr. Walters believed their work had important implications for stream restoration. For one thing, she said, evidence so far suggests that removing the overlay of sediment may encourage streams to return to a truly natural state. But also, she added, restoration requires much more consideration of what we are trying to restore, and what might actually be a sustainable approach.
They who control the course of the stream, control the course of their own history.
I don't think there is a sentence in any scientific or policy paper ever written that liberals won't use to justify their avarice for increased government power.