The Control of Nature.

THE BOOK OF GENESTS relates how God created the earth and placed man on it. When man proved unworthy of the Garden of Eden, God expelled him to live by the sweat of his brow. Now, millennia later, John McPhee writes in The Control of Nature that man has rebuilt the earth the better to suit himself, but in the process has created, not a new Garden of Eden, but a kind of perpetualmotion rowing machine that makes him sweat harder than anything God ever dreamed up.

The book is divided into three long chapters. The first is about the forcing of the Mississippi River into a straitjacket of levees, diversion dams, and flood-control reservoirs, all designed to protect New Orleans, the other delta towns, and what you might call .the American Ruhr-that vast industrial zone lining the river and using its water. The confining of the Mississippi to a walled, swiftly flowing channel robs the delta of silt and floods, and creates a dynamic that pushes the Army Corps of Engineers to greater and greater exertions. Deprived of silt, the land sinks, while the walled river channel, which requires ever-higher levees, rises above the surrounding land, "The river," McPhee writes, "goes through New Orleans like an elevated highway"; people on the streets must look up to see the ships. The Corps has a tiger by the tail, and can only ride it. As the starved land falls away, as the river races at higher and higher speeds down what had been a twisting, changing channel, as the confined, impelled river hurts its silt farther out into the Gulf, greater and greater feats of engineering, and more and more concrete, are required.

The second chapter is about the fight to keep a flow of lava from engulfing an important fishing harbor and town of five thousand on the Icelandic island of Heimaey. To stop the flow, islanders and people who had come over from the mainland to help poured huge amounts of water onto the advancing lava, freezing its outer edges into a wall that turned aside enough of the molten outflow to save the harbor and much of the town.

The event was Promethean for Iceland. At first people laughed at the id"pissing on lava," but later the entire country got behind the effort. That was in 1973, but even today you won't hear Icelanders boasting that they "stopped" the lava; they have too much respect foT the volcanic forces that underlie their nation's land. Instead, they say the lava may have been turned by luck. There is no talk in Iceland, as there is on the Mississippi, of putting nature in a hammerlock, of guiding it, of freezing its processes in time for the convenience of man.

The third part of the book is about Los Angeles, about the debris that tumbles down off the San Gabriel Mountains and the hubris that rises up from the city. When winter storms flash over land laid bare and made erodable by fires, the hills are capable of burying an entire community in an hour or so. To prevent this, L.A. has built scores of huge debris basins-dry reservoirs to catch the mud-rock slurries as they flow off the hills with great force and in great volume. In times of need, L.A. mobilizes fleets of trucks and earth-moving equipment to empty the basins and protect those who live in the canyons, in the interstices of the dragon's teeth. But the talk in L.A. is not about God or Promethean acts; it is about litigation. People have a right to live in the canyons; so when the debris basins don't do their job, residents sue the city. And when the city trucks in sand to the beaches to substitute for the debris trapped by the basins, which therefore no longer reaches the oceanfront, the sand had better be of the right color, or complaints will flood City Hall.

There are two wonderful things about this book. First is the graphic power of McPhee's writing. A reviewer is tempted to forgo analysis and just quote: "Even at normal stages, the Mississippi was beginning to stand up like a large vein on the back of a hand." McPhee's descriptions of engineering feats are given weight by his understanding of geological processes. He understands the Mississippi, for example, because he understands the Rocky Mountains, which supply much of the river's sediment and water. McPhee's writing is also distinguished by its tone, which is neither moralistic nor self-righteous. The general of the Army Corps in charge of the Mississippi fortifications gets as respectful a hearing as the lawyer-ecologist who says that after the stealing of the sun and the running of rivers backward, "The third greatest arrogance is trying to hold the Mississippi in place." McPhee lays out the case for control in strong terms. "For nature to take its course was simply untbinkable. The Sixth World War would do less damage to southern Louisiana. Nature, in this place, had become an enemy of the state."

Yet, despite the evenhanded way in which McPhee treats the issues and the people he interviews, this is an intensely moral book. McPhee understands that the source of our problems is neither evil man nor bumbling bureaucracy. It is our own innocencethe innocent desire of a Louisiana town to protect itself from the Mississippi, and of a productive, hard-working Icelandic village to save itself from a wave of fiery molten rock.

There is no doubt that the Army Corps, given the resources, can continue to hold the Mississippi in its channel and maintain the present precarious, destructive balance-or that L.A. can continue to live, in ,relative safety, in the shadow of the San Gabriel range. We won't lose these emplacements because of failure on the part of our engineers, but because of eventual changes in attitude. The costs -in money and to nature-will become so high that someday society will cut through a bank of thought and entrenched attitudes and end up in a different moral channel. What that happens, the Mississippi will follow, cutting loose from its present fortified, elevated interstate highway, and flopping over into the Atchafalaya-the channel that, if not for the Corps, would have captured the river decades ago, and dried up New Orleans and the American Ruhr.