Why build levees

The windmills of Holland pump water from behind the dikes and back out to sea to keep the land dry. Thinking long term : While the team of engineers in New Orleans tried to build levees strong enough to withstand the strongest possible storm in years, Dutch engineers designed a system strong enough to match the kind of catastrophic storm that only occurs once in 10, years. Less reliance on solid barriers : Instead of constructing increasingly bigger barriers like levees and floodwalls, Dutch engineers have sought to create better ways of absorbing floodwaters in marsh plains and specially constructed rivers.

In some cases, this even involves setting dikes farther back from the water. New textiles : The Dutch also developed tough, synthetic textiles to better anchor earthen levees. These prevent soil movement and water penetration. The New Orleans levee system began using this technology following Hurricane Katrina.

Better monitoring systems : In addition to commanding more stringent, centralized control and maintenance of their dikes, the Dutch also use automated surveillance systems to keep an eye on how their levees are holding up. They installed fiber-optic and electronic sensors in dike structures to report changes back to a central monitoring station.

Several other systems monitor water pressure and water level. June Gonzales, John Moreno. Storm memorial delayed. July 12, Louis Post-Dispatch. Levin, Alan and Pete Eisler. January Cite This!

Try Our Crossword Puzzle! What Is the Missing Number? More systemically, both local jurisdictions and U. I once did an interview with a reporter who broke the ice by asking, "So Prof. Pinter, why do you hate levees? This is not new wisdom. Today in , and after the floods that will inevitably come in the future, we need to resist the temptations of political expediency and apply the hard-won lessons of how best to manage our flood risk. The views expressed are those of the author s and are not necessarily those of Scientific American.

Already a subscriber? Sign in. Thanks for reading Scientific American. Create your free account or Sign in to continue. See Subscription Options. Go Paperless with Digital. With the authority of the Corps of Engineers behind him, Humphrey's dogma of "levees only" prevailed for decades: "Many plans have been suggested for the prevention of floods on the Lower Mississippi—Outlets, Reservoirs, Cut-offs, Diversion of Tributaries, and Levees.

Get smart. Sign up for our email newsletter. Sign Up. Read More Previous. When built with a broad, well-compacted base, levees can be topped with sandbags or water-inflated dams. To keep the permanent levee at a low or variable height, you may choose to build the system to protect against frequent, low-level floods, but design the base so the levee safely can be topped with temporary barriers for the less frequent, higher floods.

If the depth of flood risk increases in the future, a well-founded levee can be topped with a permanent floodwall or additional earthen material.

Neighbors often view levees as aggravating their own flood situations. Protecting the area right around a building may be less objectionable than excluding water from your entire lot. Things to Remember Levees must be built to withstand the forces of standing water and flowing water.

The potential effects of water currents should be analyzed by an engineer. Levees may require underground extensions to prevent seepage through the soil, depending on soil type, water depth and flood duration. You must provide drainage for rain that falls inside the levee system when it's NOT flooding and when it IS flooding. It's very hard to add drains once the levee is built, so make sure the number, size and locations are right before you pile on the dirt. In a large flood emanated from the Ohio River watershed, raising the waters to levels such that the Birds Point-New Madrid floodway was used, opening the floodway by dynamiting the Fuse Plus levee.

This released huge volumes of water and eased the flood downstream. One of the lessons from the flood was that roads should be added to the levees to aid in moving material from place to place during floods. In the MRC began redesigning levees to be stronger to avoid failure, recognizing the importance of compaction for reducing the chances of levee failure.

Levees fail by three main modes: underseepage of water beneath the levee, where the pressure from the high water opens a channel causing catastrophic failure; hydraulic piping, in which the water finds a weak passage through the levee; and overtopping when the water flows over the top of the levee and erodes the sides. Levees can also fail when the river current scours the base of the levee during high-flow conditions, as happened in many of the Mississippi River floods, and this causes slumping and massive collapse of the levee.

Mass wasting is also promoted by long-term floods in which the water gradually saturates the pores of the levee, weakening it, causing massive liquefaction and catastrophic failure, leading large sections of the levee to collapse at the same time. Most levee failures happen during times when the flow has been high for long periods, since this increases the pore pressure, scouring, and liquefaction potential of the levee.

By the MRC was modeling floods with twice the previous discharge, examining the ability of the river and levee system to handle a discharge of 3,, cubic feet 2,, m3 per second. Then the flood of hit the Mississippi River basin with one of the highest floods recorded in years.

In terms of flood management, the flood of brought the realization that building levees, wing dikes, and other navigational and so-called flood-control measures had actually decreased the carrying capacity of the river. This meant that for any given amount of water, the flood levels called stages would be higher than before the levees were built. The catastrophic floods of provided another test of the levees, and the new system failed massively.

The constriction of the river caused by the levees led to numerous cases of levee failure, overtopping, crevasse splays, collapse, and massive amounts of damage as had never been seen along the river. Approximately two-thirds of all the levees in the upper Mississippi River basin collapsed, were breached, or were otherwise damaged by the floods of Climate Policy Watcher Survival current. Responses Olli When were levees first constructed along the mississippi river in louisiana?

Semret How high is the mississippi river levee in ? Matthias How high is the Mississippi levee in New Orleans? Heribald What happens if there is a break in the mississippi river levee? May What year was the muscatine levee built? MARY When were miss river levees built?