“Essayons!”: The Army Corps of Engineers and Water Management

28 Jun

In pursuing my Master of Environmental Science degree at the Yale School of Forestry and Environmental Studies, I conducted research on the Army Corps of Engineers to examine whether and how the institutional culture of the agency has been changing in response to increased societal pressure to concentrate on environmental management and protection.  The unique perspective this research gave me on the culture and history of the Corps inspired this analysis on the agency’s current challenges.

This is the first in a series of posts about the Army Corps.  This first post contains background on the Army Corps, its history of flood control management, and some of the factors behind the strength of this year’s flooding.

Army Corps red and white castle logo

The Army Corps of Engineers usually lies pretty low.  Engineers speaking earnestly while wearing hard hats and castle logos do not make for very tempting paparazzi bait, so the last time we heard this much about them was five years ago, when the levees failed in New Orleans during Katrina.  Five years before that they were also in the news, when journalist and author Mike Grunwald wrote a series for The Washington Post detailing pork-barrel spending, economic boondoggles, environmental destruction, and other ills that he considers the hallmarks of the agency.

2011 Spring Flooding in Minot, ND. From ND Dept. of Emergency Services

We’re beginning to hear from the Corps again as the divisions on the shores of the Mississippi and Missouri rivers and their tributaries are forced to make tremendous decisions day after day in order to deal with the record-smashing flooding in that region. These rivers, along with the Ohio river, cover over 1 million square miles of the United States.   More small communities and tracts of cropland fall victim daily to inundation as levees either fail due to the incoming cascades of water or are deliberately destroyed in order to spare an urban or industrial center downstream.

Interesting–it turns out that when the Army Corps makes the news, it’s usually for something terrible.  It almost makes you feel sorry for them.

However, the Corps is made up of duty-bound professionals, and they do their best to speak in the language of probabilities, cost-benefit analyses, risk tradeoffs, and so on.  So we don’t feel that sorry for them–we end up feeling sorry for the people the Corps’ decisions end up hurting, the ones whose crops and homes are flooded and who don’t have enough flood insurance to rebuild or replant.  Some of those farmers and citizens of the heartland are preparing lawsuits against the Corps:

Ed Marshall is a farmer here who now has about 8,000 acres underwater. He recognizes the Corps’ need for action, and like many farmers here in Charleston, he’s resigned to the fact that the Corps will continue to operate the floodway for generations to come. But Marshall and others fault the Corps’ procedures: detonating explosives over a two-mile stretch of levee, allowing for a crush of water to pound onto the spillway…

[These farmers] know that there are big risks involved to farming in a place like this. Many of their deeds contain flowage easements, allowing the Corps to release water at will, and folks seem to recognize that it’s for the greater good to flood this big, 130,000-acre chunk of their county.

But [25] farmers here have filed a class-action lawsuit against the Army Corps of Engineers.

Hang on.

There are a few significant questions we should unpack here.  Why is the Army Corps of Engineers in charge of flood control in the US?  Why do we have all these big strong levees everywhere, holding in the fourth-largest river in the world, if they are sometimes going to be burst by design and flood people they were presumably designed to protect?  Why are the floods this year so bad?

The Army Corps and Flood Control

The Army Corps is the oldest federal agency in America, created during the Revolutionary War to help the Continental Army build their own forts, bridges, and harbors and sabotage those of the British.  This entwining of military and infrastructure missions has continued and grown; the Corps eventually took charge of ensuring safe navigation on the nation’s waterways as a matter of national security (for ensuring the protection of supply lines) and, later, to protect commerce.  In 1899 Congress, concerned about the proliferation of private dams that obstructed navigation, expanded the role of the Corps with the Rivers and Harbors Act.  The agency now had the power to permit or deny construction of any structures, excavation from or fill into navigable waters, and the discharge of refuse material.

Damaging Mississippi floods in 1912, 1913, and 1916 built momentum for a federal takeover of flood control, but the real trigger was the great flood of 1927:

Great Flood of 1927, unknown region. Image from National Geographic photo gallery "Flood Pictures: Mississippi River at its Worst". Click image for full gallery.

And the rains came. They came in amounts never seen by any white man, before or since. They fell throughout the entire Mississippi River Valley, from the Appalachians to the Rockies. They caused widespread flooding that made 1927 the worst year ever in the Valley. More water, more damage, more fear, more panic, more misery, more death by drowning that any American had seen before, or would again.

The Corps itself drew up a plan for an immense, integrated levee system, Congress considered it, and in 1928 the plan was authorized and put under the jurisdiction of the Corps.  Following more devastating flooding in the 1930s, Congress passed the 1936 Flood Control Act, officially putting the Corps in charge of flood control for the nation’s waters.

The Levee System

The current Mississippi River flood control system was developed following the 1927 Great Flood.  This year’s flooding, while within the design capacity of the system, is second only to that massive event.  The system was deliberately designed with designated spillways where farming was allowed, since the probability of breaking levees to flood the spillways was considered an acceptable risk to weigh against the economic benefits of farming that fertile cropland.

Ancient Courses: Mississippi River Meander Belt. Cape Girardeau, MO - Donaldsonville, LA. Prepared by Harold N. Fisk. PhD., for the USACE in 1944.

These spillways reflected a concession to “natural” flood control: the Mississippi River has never held still for long.  The Big Muddy has changed course thousands of times over geologic history, and its historic natural floodplain may have been over a hundred miles wide at its widest point.  Chanelling the river into one set course, defined by levees, locks, and dams, facilitated the transformation of a river that lifted and resettled the top soil of a continent into one that produced a sustained economic boom in the center of America.  By changing the natural river to a commercial one, the Corps sought to tame it, and has largely succeeded: agriculture and shipping alone produce up to $12.8 billion in revenue each year on the lower Mississippi, and $6 billion on the upper.

It’s not unnatural to have a big flood.  What’s unnatural is that the river has been forced to stick to one course for so long, hemmed in by levees. The most natural kind of flood control would be similar to that famously practiced by ancient Egyptians along the Nile: families had homes on stilts or in villages outside of the floodplain to live in when the Nile was in spring flood, and when the water receded they planted, grew, and harvested crops in the newly replenished soil.

Such a flood control policy might be called “soft,” while the traditional Corps practice of building structures is a “hard” form of flood control.  Soft flood control would be cheaper, both in infrastructure costs and insurance losses, but it would be less predictable in our hard world.  The nation demands predictability for growth, investment, and commerce, and the Corps of Engineers, trained in construction and building, is happy to oblige.  It’s hard to get an agency of engineers to endorse a policy of not-engineering.

This Year’s Flooding

Excerpt of a Corps map showing estimated maximum flooding in 1927 flood (blue) vs 2011 flood (green). Note that while the crest height of the river is just about as high in both floods, the levee system is largely doing its job. Click the image for the full map.

The 2011 Floods are historically bad for three reasons: one is the psychological outcome of the “hard” flood control we have chosen for the country.   Citizens get used to solid walls that last for decades or generations and are unprepared when they fall spectacularly.  In the meantime, entire families live and die in the shadow of the levees and become used to the protection they imply.  Over time they make additions to their houses, plant more intensive crop rotations, and otherwise discount the idea that the river would flood the banks.  They grow complacent, perhaps.   The disconnect is most jarring when we consider families living and working in the spillways on land that will be flooded first in the event that high water threatens a downstream urban center.

The second reason is physical, and also linked to the levees: preventing the rivers from returning to their floodplains has accelerated the destruction of wetlands, both via conversion to cropland and because of simply disconnecting them from the river.  Without lots of wetlands in places like Minnesota, any rain that hits the ground does not get absorbed and then released slowly into the river but instead rolls along the farm field’s surface, into the subsurface tile drains, into the irrigation ditches, and then into the river, quickly.  We get higher peaks in water levels that occur more quickly, and are generally harder to control.  The same “flashiness” is contributed to by the levees themselves.  Since flood water can’t reach the floodplain, spread out horizontally and soak into the soil gradually, it just stays in the river channel, getting higher and higher and thundering downstream.

Finally, there’s just more water in the system this year.  A lot more water.  The Corps increased its release levels on Big Bend Dam, on a Missouri River tributary in South Dakota, to 165,000 cubic feet per second (cfs) this week.  The previous record was 74,000 cfs in 1997.  If they don’t release these high-pressure water levels, or the dams would breach, leading to even more sudden and out-of-control flooding.  Record-breaking snowpack and record-breaking spring rains have swollen tributaries across the Midwest, prompting Bill McKibben of 350.org to caution us not to wonder whether extreme weather events might be related to climate change:

If you did wonder, you see, you would also have to wonder about whether this year’s record snowfalls and rainfalls across the Midwest — resulting in record flooding along the Mississippi — could somehow be related. And then you might find your thoughts wandering to, oh, global warming, and to the fact that climatologists have been predicting for years that as we flood the atmosphere with carbon we will also start both drying and flooding the planet, since warm air holds more water vapor than cold air.

After years of bounding their conclusions with careful assessments of uncertainty and qualifications, scientists are finally ready to begin attributing the rising pattern of extreme weather events to human-caused climate change.  Even without a known contribution from climate change, however, our increasing use of “hard” technology to protect ourselves from nature blurs the line between a natural and a man-made disaster.  With climate change, however, the frequency and intensity of weather events are predicted to continue rising, but it’s hard to say by how much.  This may negate the major advantage of a hard flood control system, predictability.  In a time of change, we should be prepared to expect the unexpected.

In the next post, I’ll get into an analysis of some of the nuances around risk perception and the uneasy relationship the Corps has with the communities it protects (and, occasionally, allows to flood).

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