In this graphic from the restoration authority, the land that will
be lost to erosion if the plan isn’t undertaken is shown in red.
Six years after Hurricane Katrina devastated New Orleans and the Louisiana coast, the state’s Coastal Protection and Restoration Authority has finally released a draft of a plan to try to keep it from happening again. How? By restoring the wetlands along the Mississippi River Delta, which we have more or less systematically destroyed but used to act as buffers between storm surge waves and inland cities.
Previous plans had relied on mainly on building levees and seawalls, so it’s striking that this plan, which would unroll over the course of 50 years at a cost of $50 billion, focuses on wetland restoration, writes Mark Fischetti, who has been covering this issue for Scientific American for years. Here’s how it would work:
Along the outer edge of the torn-up coast, furthest from New Orleans, former barrier islands that have been worn to thin wisps of land would be broadened with sandy sediment, mostly dredged from the ocean bottom and conveyed through pipelines. Natural ridges of land along the coast would be strengthened in similar fashion. Together, the islands and ridges would form a dotted line around southeastern Louisiana that can cut down storm surges. They would not all connect, so wind-driven water could still find its way through, but the many segments would break up the incoming wavefront into chaotic eddies flowing in conflicting directions that would at least partially cancel out one another.
The plan is already drawing ire from fishermen, who say that current restoration projects haven’t had much effect, and that all this shuttling of sand and water will interfere with their livelihoods.
Read more at Scientific American.
Images courtesy of the Coastal Protection and Restoration Authority
The city of Piraeus, in 2008
What’s the News: Chalk up another win for the ancient Greeks. The Greek historian and geographer Strabo wrote nearly 2,000 years ago that Piraeus, a small peninsula near Athens, had once been an island—and a new study in this month’s issue of Geology shows he was right.
The city of New Orleans’ defenses are certainly better than they were five years ago, when Hurricane Katrina breached the levees and flooded the city. With the five-year anniversary of that disaster upon us, however, the question that hangs in the air is: Would those refurbished barriers stand up to another Katrina, or something worse?
In the last five years, the federal government has invested about $15 billion to revamp the New Orleans levee system.
This time, tougher foundation material like a mixture of construction clay and cement, is being used in the soil to hold structural sections of wall designed as an inverted T instead of their previous I-shape. The new design is considered stronger, allowing steel pillars to bracket each end into the ground. Total completion is expected in June 2011. [Christian Science Monitor]
The region today known as Iraq was once known as Mesopotamia, which means “Land Between the Rivers,” and since that ancient time the land between the Euphrates and Tigris rivers has been renowned for its fecund soil and thriving farms. But now the Mesopotamian cradle of civilisation seems to be returning to desert [New Scientist].
Decades of war and mismanagement, compounded by two years of drought, are wreaking havoc on Iraq’s ecosystem, drying up riverbeds and marshes, turning arable land into desert, killing trees and plants, and generally transforming what was once the region’s most fertile area into a wasteland…. “We’re talking about something that’s making the breadbasket of Iraq look like the Dust Bowl of Oklahoma in the early part of the 20th century” [Los Angeles Times], said Adam L. Silverman, a social scientist with the U.S. military.
The state of Louisiana is losing its coastal wetlands to the Gulf of Mexico, and a new study suggests that conservationists won’t be able to turn the tide. If engineers don’t divert sediment-rich waters from the Mississippi River to help replenish a sinking river delta, about 10 percent of [the] state will slip beneath the waves by the end of this century. However, even if the engineers do try to abate the subsidence, the Mississippi doesn’t carry enough sediment to offset more than a small fraction of that loss, a new analysis suggests [Science News].
Before American settlers subdued the Mississippi and its tributaries, the river periodically overflowed its banks and spilled muddy water, thick with sediment, into surrounding wetlands. But the new study found that the Mississippi and Atchafalaya rivers today carry only half the sediment they did a century ago — between 400 million and 500 million tons a year then, compared with just 205 million tons today. The rest is now captured by more than 40,000 dams and reservoirs that have been built on rivers and streams that flow into the main channels [The Times-Picayune].
So even if Louisiana officials embark on an all-out campaign to restore the marshes through controlled levee breaks and diversion projects that bring back river water, it wouldn’t be enough to save the land–especially since sea levels are rising due to global warming. “We conclude that significant drowning is inevitable” [The Guardian], the study’s authors wrote.
An ambitious, multibillion-dollar effort to restore Florida’s Everglades is floundering due to bureaucratic delays, and the ecosystem may be close to a tipping point, according to a new congressionally mandated report. The longer the project remains stalled, the higher its cost will rise — even as the River of Grass that it’s supposed to rescue declines, the report from the National Research Council says. “If we don’t do something soon, we’re going to lose this really precious resource,” said [report coauthor] William Graf [St. Petersburg Times].
The report criticizes progress on the Comprehensive Everglades Restoration Plan, which was approved by Congress in 2000. The massive effort to restore natural water flow to about 4 million acres of wetlands was originally estimated to cost about $7.8 billion and take 30 years to complete — a price tag that has since ballooned due to rising costs…. The 2000 plan made the federal government and Florida 50-50 partners. To date, the state has committed more than $2 billion and pushed ahead alone with a few projects. Congress has only appropriated several hundred million dollars [AP].
The Environmental Protection Agency has vetoed a massive flood control project that was in the works for seven decades. The move – which puts the kibosh on the proposed Yazoo Pumps Project to reduce flooding between the Mississippi and Yazoo rivers – is only the 12th time the Environmental Protection Agency has used its authority to scrap a project under the Clean Water Act [Scientific American].
The EPA’s decision is being hailed as an environmental victory, as the plan called for massive pumps that would have drained water out of at least 67,000 acres of wetlands, irrevocably altering the ecosystem. The landscape of swamps, bayous, and cypress trees is vital to an extensive range of wildlife, including fish, migrating birds, and the endangered Louisiana black bear; the wetlands are valued not only by conservationists, but also by hunters and commercial fishermen.
The governor of Florida announced yesterday that the state is putting its money where its mouth is when it comes to conservation of the imperiled Everglades. The state has agreed to buy out U.S. Sugar for $1.75 billion, and will switch the company’s 187,000 acres of land from sugar cane fields to natural wetlands. U.S. Sugar’s property lies just south of Lake Okeechobee, the heart of the Everglades’ unique ecosystem.
Florida Governor Charlie Crist said the deal is “as monumental as the creation of our nation’s first national park, Yellowstone. This represents, if we’re successful, and I believe we will be, the largest conservation purchase in the history of the state of Florida” [AP]. Environmentalists are delighted by the conservation coup, and will be keeping their fingers crossed that everything goes as planned; under the proposal, U.S. Sugar will farm the land for six more years before turning it over to the state.