Many residents of New Orleans and Jefferson, St. Bernard, St. Charles and Plaquemines parishes could see the fruits of the improved hurricane levee system in new maps published on the Web Friday by FEMA's National Flood Insurance Program. Most locations within the levee system will see required base elevations lowered, which could mean a stabilizing or even a drop in future flood insurance premiums.
It?s not all good news, as residents of Braithwaite are already aware. Buildings outside the new levee system, such as those in Braithwaite, are likely to be required to be built higher ? sometimes as much as 7 feet higher. That?s the result of new studies that better identify the height of possible hurricane storm surges and the violent waves that accompany them, FEMA officials say.
The online publication of the preliminary ?digital flood insurance rate maps,? or DFIRMS, comes in advance of public hearings to be held by New Orleans and the parishes on their accuracy this spring.
St. Bernard Parish already has set a public meeting between 2 p.m. and 7 p.m. on Feb. 28 in the Council Chambers, 8201 W. Judge Perez Dr., in Chalmette, to allow residents to review the maps. FEMA officials also will be available to answer questions.
To view the new flood maps, contact your local floodplain administrator or follow these links: New Orleans, St. Bernard, Jefferson, Plaquemines, and St. Charles.
The hearings will trigger the start of a formal 90-day resolution period in which local governments and the public can appeal specific map location findings, said Matthew Dubois, a civil engineer and project monitor for the flood map studies for the greater New Orleans area.
Once all comments are resolved, FEMA will send a ?letter of final determination? to the city and parishes. That kicks off a six-month period during which the localities must approve the maps and adopt their standards as part of their building codes; if they refuse, their residents will be ineligible for flood insurance.
DuBois said that while the majority of areas within the improved levees will see their base flood elevation requirements lowered, there are a few locations that will see higher elevation requirements, the result of better mapping of land heights or recognition of? rainfall flooding challenges.
The improvements are the result of the post-Katrina bargain between the Army Corps of Engineers and FEMA: the corps would improve the levees to guarantee against flooding caused by surges created by a hurricane with a 1 percent chance of occurring each year, a so-called 100-year hurricane. FEMA, meanwhile, would continue to issue insurance within the levee areas, taking into account the chance of a rainfall event that also has a 1 percent chance of occurring each year.
Dubois was unable to say how much rain that would be, but one report cited in the flood insurance study accompanying the New Orleans map says there?s a 1 percent chance of between 11 and 14 inches of rain falling across the New Orleans area in 24 hours each year.
DuBois said the new levee maps represent a snapshot in time, representing the chance of flooding in mid-2012 after the levee system was completed to the 100-year standard. The maps also include the effects of a variety of drainage improvement projects that were completed at that time.
Local governments can provide evidence of the completion of additional drainage improvements -- including several Southeast Louisiana Urban Flood Control Program projects in New Orleans and Jefferson Parish that will cost more than a billion dollars over the next three years -- to FEMA in the future and get credit that can result in reduced insurance rates in their areas.
Work on the new maps is part of a national effort to digitize all flood insurance maps that began several years before Hurricane Katrina. In New Orleans, for instance, the last time insurance maps had been drawn was in 1984. Those maps used corps measurements that were based on outdated estimates of the heights of monuments called datum that were as much as 2 feet too low. The same outdated? information resulted in some area levees and floodwalls being as much as 2 feet too low before Katrina.
Following the storm, New Orleans-area parishes in 2006 adopted advisory maps that took into account the incomplete construction of the post-Katrina levee system. Those are still being used today.
FEMA completed a preliminary set of maps for New Orleans and the other four parishes in 2008, but stalled the adoption process until now to allow the corps to complete construction of the improved levee system, DuBois said.
?The corps has now reached the point where enough of the system is in place where it will defend against the 100-year storm surge,? he said.
Between 2008 and last summer, FEMA updated the maps with more information about? interior drainage improvements and provided local officials with copies of the completed maps last November.
The new maps outline a variety of changes.
In Lakeview and Gentilly, the new levees have resulted in significant drops in base flood elevation requirements. Where the elevation is now required to be 2.5 feet below sea level in Lakeview, the new map requires only 5 feet below sea level. In Gentilly, where the standard now is 1 foot below sea level, it drops to -6 feet. In the Central City area, including Broadmoor, where the present map requires a base elevation of 1.5 feet above sea level, the new map allows the base to be 1 foot below sea level.
In Metairie and Kenner, the existing maps set a base flood elevation of -3.5 feet above sea level north of the Metairie Ridge to the lakefront. That drops to -4 feet in parts of Kenner and between -3 and -5 in Metairie.
On the West Bank, areas now protected by a post-Katrina levee along Lake Cataouatche will see their base flood elevation requirements drop dramatically, from 3.5 feet above sea level to as low as -1 foot. Areas north of the V levee and west of Leo Kerner Parkway would see their base flood elevation drop from 5 feet above sea level to zero, while areas to the east drop from 1.5 feet above sea level to 1 foot below sea level.
Outside the levee, areas along Jean Lafitte Boulevard and Rosethorn Road, adjacent to the Barataria Unit of Jean Lafitte Park, will increase in base flood elevation to 8 feet above sea level, from the present 7 feet. On Grand Isle, some base flood elevations along the Gulf rise to 16 feet from present elevations of 10 to 13 feet.
East Bank St. Charles Parish residents also will see significant improvements in areas behind completed 100-year levees, with existing base flood elevation requirements of 8 feet and 9 feet above sea level dropped to between 2.5 feet and 4 feet.
Areas north of the levee along Lake Pontchartrain move from mostly 10 feet base elevation to mostly 12 feet.
In Plaquemines Parish, Belle Chasse gains from improvements of the Mississippi River levee to protect it from hurricane storm surges, with base flood elevations dropping from mostly 1.5 feet above sea level to between 0-3 feet below sea level.
The rest of the parish gets hit with major elevation requirements, the result of new studies indicating that existing levees will not protect the area from either 100-year storm surges or waves.
Braithwaite and east bank communities to the south across from the New Orleans Naval Air Station take the brunt, seeing their elevation requirement increase from 3 feet above sea level to 21 feet.
Areas to the south on the east side of the river will see new elevation requirements of 15 to 17 feet, generally a foot or two higher than the present map.
On the west side, the elevations are 14 to 15 feet with the new map, similar to the existing map except at one location just north of Triumph, which now has a 3.5-foot elevation requirement.
In St. Bernard Parish, areas inside the newly raised Chalmette Loop see the base elevation drop to as low as -2 feet in Arabi to 3 feet above sea level near Riverbend Drive, a foot or two lower than existing requirements. To the south, outside the levee system, the base increases to 19 and 20 feet from 13 and 14 feet.
Source: http://www.nola.com/environment/index.ssf/2013/01/new_maps_could_be_good_news_fo.html
Am I registered to vote Voter registration Election Election results 2012 exit polls Presidential Polls California Propositions
