NEW ORLEANS – The U.S. Army Corps of Engineers, New Orleans District, announced the Levee Safety Action Classifications (LSACs) and Risk Characterizations for levee systems in the district will be available on the National Levee Database starting Aug. 4.
The LSACs identify risk for communities by looking at three different criteria:
Hazards – the type and probability of an event.
Performance – the current state of the levee system and the past and expected performance.
Consequences – the number of people and the infrastructure that would be impacted when an event exceeds design capacity.
“Looking at the Hazards and Consequences criteria alone, we know that there is high risk in Southern Louisiana,” said Col. Michael Clancy, New Orleans District commander. “A river flood is expected annually and each year we ready ourselves for hurricane season; that coupled with the densely populated areas and the industrial infrastructure are the driving factors for many of the LSACs across the district.”
Each levee system is unique as is the reasoning behind the assignment of each LSAC. A key component on the National Levee Database are the Risk Characterizations which provide details about how the criteria (Hazards, Performance, and Consequences) were used to determine the LSAC for a system. The risk of an LSAC ranges from: Very High, High, Moderate, Low, Very Low, to No Verdict.
“Two levee systems can have an LSAC of ‘High Risk’ but for very different reasons,” said Jennifer Stephens, Levee Safety Program manager, New Orleans District. “It is important to look at the Risk Characterizations to understand the why of an LSAC on each system.”
Below are examples of levee systems with their LSACs and elements of the Risk Characterizations.
New Orleans East Bank and West Bank
Hurricane and Storm Damage Risk Reduction System and Mississippi River Levees
These systems received a LSAC of High Risk based on the following criteria:
Hazards – High likelihood of tropical storms and hurricanes on an annual basis. Annual high water event on Mississippi River.
Performance – Best risk reduction system the Greater New Orleans area has ever had. Performed as designed during past events. Continued improvements and expected to perform in future events.
Consequences – 913,700 people, 325,700 structures and $170 billion in property value. (Based on the 2010 Census)
Mississippi River East Bank
Mississippi River Levees from Baton Rouge to Bonnet Carre Spillway
This system received a LSAC of High Risk based on the following criteria:
Hazards – Annual high water event on Mississippi River.
Performance – Best flood managed system in the world with proven past performance and expected to perform as deigned during future events.
Consequences – 532,300 people, 151,200 structures and $81 billion in property value. (Based on the 2010 Census)
Additionally, Risk Characterizations and LSACs for the following systems will also be available on the National Levee Database: Angola, Caernarvon To Phoenix, Bayou Sale, Phoenix to Bohemia, Morganza Floodway, Lafourche Basin, St. Jude to Venice, St. Bernard, Mississippi River West Bank - Above Morganza, Melville Ring, MRWB - Above Old River, Simmesport Ring Area, Terrebonne Basin, Wax Lake West Area, West of Atchafalaya Basin, Mississippi River West Bank - Below Morganza, and the West Atchafalaya Floodway.
“The LSACs and Risk Characterizations provide a wider view of the risk associated with a levee system beyond the physical structures,” Clancy said. “They are not a rating or grade for the levees or our local partners. These are tools we can use to communicate risk and prioritize funding for levee systems.”
These assessments are not the only material that will be available on the National Levee Database. The database will have information about: each levee system, the latest inspections, and Federal Emergency Management Agency and the National Flood Insurance Program (NFIP).
The LSACs and Risk Characterizations alone do not impact NFIP accreditations. The risk characterizations look at a whole system’s risk rather than the individual risk and the 1 percent specifications of the NFIP.
“New Orleans currently has the best flood risk reduction system in its history and it continues to improve with projects like levee armoring,” Clancy added. “But no system can eliminate the risk of a hurricane or flood. Tools like the National Levee Database, LSACs, and Risk Characterizations help remind us to have an evacuation plan in place, enroll in the flood insurance program, and to listen to evacuation orders.”
The complete Risk Characterizations and LSACs for systems in the New Orleans District will be available on the National Levee Database (https://levees.sec.usace.army.mil/
) starting Aug. 4. Additional information can be found at www.mvn.usace.army.mil/LSAC/