Challenges of keeping Mississippi River in check discussed at meeting of Louisiana coastal authority
By Benjamin Alexander-Bloch, Times Picayune16 June 2011
The Louisiana Coastal Protection and Restoration Authority on Wednesday laid bare the multilayered and often contradictory juggling act that accompanies Mississippi River management, from the responsibility of dredging the river’s navigation channels, to its potential coastal building power, to the unprecedented Gulf of Mexico dead zone anticipated this year due its increased flow.
David Grunfeld, The Times-PicayuneThis container ship on the Mississippi River in New Orleans was photographed May 15,
In a centuries-old balancing act, the government on the one hand must shield communities and commerce from the mighty river’s volatility, while on the other maintain the river’s ability to keep coastal erosion at bay by using its fresh water to balance salt water’s eroding potential and distribute its sediment to mitigate coastal land loss.
John Barry, a member of the Coastal Protection and Restoration Authority and author of “Rising Tide,” a book about the 1927 Mississippi River flood, explained at the authority’s meeting in Baton Rouge how the flood this year luckily did not reach the Great Mississippi Flood’s magnitude.
In 1927, it ran at 3 million cubic feet per second, he said, explaining that a flow of one cubic foot means the water would cover two acres of land with one foot of water each day.
Meanwhile, the Army Corps of Engineers pegged the 2011 river flow at about 2.3 million cubic feet per second, Barry said, roughly a third less than the former’s might.
After the 1927 flood, the corps realized the river had to be given room to spread out, Barry said, and by creating the Morganza Floodway essentially doubled the river’s width, lowering flood height.
Also after the 1927 flood, levees along the lower part of the Mississippi were built to a much higher standard than any other levees in the country, he said. Barry says the levees will hold a once-in-750-years flood.
After that explanation, there were many dark references made by Barry and other advisory members about Louisiana hurricane protection. It is built at so-called 100-year protection, meaning to protect against a surge created by a hurricane with a 1 percent chance of occurring in any year.
Barry called 100-year protection “the lowest standard in the developed world” and one that most use protect cattle, not people. In Japan and Holland, they protect against storms to a 10,000-year standard, he said.
He added the Mississippi River flood this year exceeded 100-year protection by three to four feet, and the river also has done so in 1927 and 1937, and in along some banks in 1973.
And yet hurricane protection and the Mississippi easily tie together. The river’s potential to restore wetlands that in turn protect coastal communities from hurricane storm surge must be harnessed, many at the Baton Rouge meeting on Wednesday said.
Louisiana Coastal Protection and Restoration Authority Chairman Garret Graves and others pointed to the state’s plans to update its 2007 coastal restoration and hurricane protection master plan by 2012 as an opportunity to tackle concrete plans to utilize that coastal building and protection potential.
Yet the financial price tag on such plans has continued to be a hindrance.
While Congress in 2007 approved additional river diversion measures that would deposit freshwater and sediment into needed areas of the Gulf, Congress never appropriated the money for the projects.
The Coastal Protection and Restoration Authority on Wednesday pointed out the financial risks associated with coastal vulnerability.
Graves referred to the $150 billion in expenses resulting from Hurricane Katrina.
And R. King Milling, a member of the advisory committee and chairman of America’s Wetland Foundation, said that the loss of wetlands would bring a financial burden.
A study commissioned by the foundation and Entergy states the loss of wetlands, coupled with rising sea levels and more frequent hurricanes, would cause economic losses along the the Gulf of Mexico region totally $350 million over the next 20 years.
Looking forward with more optimism, Coastal Protection and Restoration Authority members said fines from the Gulf oil spill could provide financing for coastal restoration projects, as could offshore oil royalties the state should begin receiving in five years.
Benjamin Alexander-Bloch can be reached at bbloch@timespicayune.com or 504.826.3321.
http://www.nola.com/environment/index.ssf/2011/06/challenges_of_keeping_mississi.html