Watersheds provide numerous and diverse services to humans, according to the EPA's online Watershed Academy. These include the purification of air and water, detoxification and decomposition of wastes, regulation of climate, regeneration of soil fertility, and production and maintenance of biodiversity, from which key ingredients of our agricultural, pharmaceutical, and industrial enterprises are derived.

A more nebulous benefit, one which is difficult to quantify, is the provision of aesthetic beauty and intellectual stimulation that lift the human spirit. Ways in which this occurs are...