You can read Phillip Ratliff's piece on the Cahaba River and the 20th anniversary of the Cahaba River Society online at B-Metro Magazine. But it'd recommend picking up a copy of this month's magazine. The article is great and the photos by Hunter Nichols are tremendous.
The article captures the economic and conservation arguments for protecting the Cahaba but touches some deeper arguments as well:
Excerpt: "The white water rushing over limestone, the Cahaba lilies, the map turtles and raccoons, even the lowly hellgrammite inspire awe. Haddock would call this the aesthetic argument for conservation. We should protect the Cahaba, the argument suggests, for the same reason we preserve Van Gogh’s Starry Night."