RIVERS

Except for a long digression re the flora and fauna of the Potomac, this is a compact, clear and pertinent introduction that is also an overview. A sampling of river lore leads to a look at the world's most important from Australia's Murray to our Mississippi and then to an extended examination of how a river starts, how a channel is formed, how a System arises; noted are the key role of tributaries, the hazards and benefits of floods, the principal control measures (levees and dams); also explained is the formation of falls, meanders and mouths (deltas, drowned). Scattered remarks on river wildlife (and the Potomac ramble) precede a capsule history of rivers in America -- formerly mainstreams, now mired. As relief there's mention of the proposed National Wild River System.