John McPhee's The Control of Nature is a really good book and I'm glad I read it right after Annals of the Former Earth. Through three broad stories, McPhee addresses the theme of man versus nature, and how humans are able to live with nature successfully, or unsuccessfully try to harness it for our own ends. A major issue in all three books is sprawling development, bringing people closer to dangerous areas where humans are not meant to live. In so many of these stories, people are just building their houses in unsafe areas where they are guaranteed to run into problems with rivers, earthquakes, or rockslides, but they do it anyway because prices are too high in the city.
Atchafalaya
Atchafalaya is about more than just the Atchafalaya River, a distributary of the Mississippi River, siphoning off water from the path to New Orleans and instead diverting it on a shorter path through Morgan Town. On the theme of controlling nature, McPhee meets with the Army Corps of Engineers and fishermen from the bayou to learn about the swampy region of the Mississippi Delta.
The difficulty with nature is that when mankind builds in a place, we often expect it to stay the same and rely on that illusionary permanence. In the Mississippi Delta, we've built cities, oil refineries, and miles upon miles of farms that all depend on the Mississippi River following one specific route that it doesn't want to follow. It has a shorter route along a steeper distributary called Atchafalaya, and since the 1860s (specifically the flood of 1863), more water has flowed through Atchafalaya every year. It was at that time that settlers in the area cleared the "Great Raft" of logs that clogged the Atchafalaya for centuries before Europeans arrived, clearing the way for the father of waters to take a more direct route to the Gulf. But this wasn't some massive intervention. The river would have moved one way or another, because the Mississippi River has been shifting here and there in an arc over a hundred miles wide, and some hydrologists believe its even gone through Texas at different times. By the late 1940s, one-third of the volume of the Mississippi River departed the continent through the Atchafalaya River. Of course, this would mean the end of New Orleans and Baton Rouge if it were to take over completely, so the Army Corps of Engineers stepped in.
McPhee compares the Mississippi unfavorably to the Nile. Unlike the Nile, whose regular floods sustained life, agriculture, and civilization for thousands of years along its banks, the Mississippi, while pushing fertile soil downstream, is not so beneficial. There is no high ground in the Delta, so floods destroy homes. The waters of the Mississippi are cold, unlike the warm Nile, so they kill crops. And since floods can stand for months at a time, they can kill an entire year's agriculture. To successfully farm around the Mississippi, it cannot exist in its natural state.
The path the Mississippi takes to the Atchafalaya is along the Old River, which the Army Corps of Engineers dammed in 1963. But that was only the beginning. The Mississippi remained (and remains untamed). For the last three centuries (and probably further back on a smaller scale) residents of the Mississippi Delta floodplain have been building levees to contain the river. But the levees helped to aggravate the problem of flooding, as all they could do is build a higher aqueduct, amplifying the force of the river downstream since it had nowhere to flood and relieve pressure upstream. New Orleans faces a similar problem of the cure being worse than the disease. Because the city is shaped like a bowl, with its highest points along the Mississippi River and Lake Pontchartrain, the rain that falls collects in the middle, and whatever doesn't evaporate must be pumped out. But removing the water lowers the water table and further aggravates the cities subsidence, making it lower and lower. The containment of the River has reversed the trend of building new land out in the Gulf as silt flows through it, but it has not abated the pressure of floods completely. Now erosion threatens the Louisiana coast from the sea while it faces floods from the River. Like a rock and a hard place, Louisiana and its citizens are trapped between floods and high water.
Cooling the Lava
The second section covers a volcanic eruption in 1973 on Heimaey, an island off the coast of southern Iceland, which resulted in the creation of a new volcano whose name is Eldfell, meaning "Hill of fire." Specifically, McPhee writes about the attempts by the Icelandic authorities and the US Navy to use waterspouts to control the flow of the lava and direct it away from the harbor, which was critical to the island's fishing community, itself critical to the Icelandic economy.
McPhee tells us about how rubbing away just a third of an inch of ash reveals temperatures so hot you have to pull your hand away, but that it is insulated by a thin layer of ash. When pumping crews arrived just after the explosion, they realized that just a couple of inches of hard rock on top of the lava was enough to support a person. But lava on the ground wasn't the only threat the pumping crews faced. During the weeks of the eruption, "bombs" fell from the sky. These were balls of lava with hardened exteriors and liquid interiors that shot from the mountain. Sixty-pounders fell as far as two-thirds of a mile from the eruption, and some that travelled a third of a mile weighed a third of a ton. To avoid them, the crewmen had to travel in pairs: one to direct them along the ground, and one to look up at the sky. If a bomb was headed their way, they were advised to watch it, wait until they were clear that it was going to hit them, and then step out of the way.
But the major difficulty of managing lava flow (once you've gotten the pumps in place to actually do it) is how to choose where to send it. In 1973, the Icelandic authorities directed it away from the harbor. But any place you cool lava will form a wall. This protects the area behind the wall, but diverts more lava to everywhere else. The result was that some houses and parts of the city were destroyed that would have otherwise survived. But it was probably worth the cost to save the harbor, and the heat from the lava has provided the island with millions of dollars-worth of energy. What may not have been worth it is the loss of population, not from deaths, but from the many people who evacuated the island and chose not to move back.
McPhee moves from Iceland to discuss the volcanoes of Hawaii, which are very similar. It reminds me of similar trips in Annals of the Former World, where geologists travel far and wide to see the future of one rock formation, already manifested on some other continent. McPhee writes that there are 5,000 miles of Hawaiian islands, created by the Pacific Plate moving over a hot spot under the Earth, which causes a new volcano to form, erupt, die, and erode back into the sea. The oldest islands in the state of Hawaii have been above water for five million years, but there are older islands that are part of the same chain but are in Japan, to the northwest. These islands get lower and lower as you travel north until they disappear under the waves due to erosion. One big difference between Hawaii and Iceland is that while Hawaii is a plate moving over a hot spot, Iceland is at the cracking center of new-forming land. Iceland sits astride the Mid-Atlantic Ridge, and so Easter Iceland is moving east with Europe while Western Iceland is moving west with North America as the Atlantic widens. The rock at the edges of Iceland is young, just 14 million years old. And the rock at the center of Iceland is still liquid, and therefore has no age.
Los Angeles Against the Mountains
The third and final book of The Control of Nature is set in the San Gabriel Mountains, north and northeast of Los Angeles. I found this book to be the least fact-laden of the three, with less information and more horror stories of people's houses being swallowed by landslides. The problem with the mountains in Los Angeles is that they feature canyons, which load with debris loosened by wildfires and washed into a slot during rainstorms. These things are loaded like guns, and when the right storm comes, it all gets loosed at once, destroying whatever is in its path with mud, boulders, and whatever it picks up along the way.
Usually its not the first, early-winter rains that set it off. But those first rains usually just add to the waiting pile. Some years it never has a landslide. That's because it depends on if the chaparral region above the mountains needs to have burnt to trigger the cataclysm. The soil in the area will absorb water if unburnt, but after being exposed to high temperatures. the soil loses its absorbency, and water will just slide off it. It's even worse when the chaparral burns after a long period without burning. If it burns regularly, there isn't so much "stuff" that has been waiting to slide down the mountain. But if it has been decades, you can bet there will be a very bad landslide.
Yet people keep moving directly into the path of the landslides that the San Gabriels unleash. And they keep refusing to take measures to stop them. McPhee interviews an official from the Department of Public Works, who says that they needed to stop calling it "debris" and start calling the places where they collect the stuff that comes down the mountain "sediment-placement sites." He says they run into problems with the Sierra Club, the Forest Service, Fish and Game, and the California Environmental Quality Act, all things designed to improve the environment. Yet the result is, if they can't build large pits to collect the debris that comes off the mountain, people will die.
Conclusion
I just want to throw a paragraph in here about how good a writer John McPhee is. He's amazing not just for his ability to describe a thing or a place, but for all the details he includes that you wouldn't think to put in a book about another subject. Like when he mentions that a chef on the island of Heimaey is a "master of hot smoked puffin" which is a dish that tastes like something between corned beef and herring. McPhee writes that "Burgundy flesh is in the puffed-up chest of the puffin. It is served with new potatoes and sweet thin slices of pickle." He is a pleasure to read.
Miscellaneous Facts:
- In 1852, the Yellow River shifted course away from the Yellow Sea, establishing a new mouth four hundred miles from the old one. Other rivers have done similar things.
- In Sicily in 1669, Mt. Etna erupted and the citizens of Catania went up the slopes and used pickaxes to break the crust on one side and direct the lava flow away from Catania towards the neighboring town of Paterno. A law was then passed to stop that sort of thing. It was the first recorded attempt to divert a lava flow.
- Mauna Loa has erupted on average every 3.5 years since records began two centuries ago.
- Kilauea was in a state of continuous eruption for the entire nineteenth century.
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