3 minute read
Multiple Approaches, Same Level of Risk-reduction
from America's Engineers: The People, Programs, and Projects of the U.S. Army Corps of Engineers '24-'25
Hurricane and storm flood management come in different forms
BY RICKY BOYETT
Water is the lifeline of coastal Louisiana, the foundation on which the region’s economy, recreation, and inimitable cultural heritage is built. Water is also the area’s greatest threat. Whether from riverine, rainfall, or tropical weather events, risk of flood damage is inherent to the people who live and work in south Louisiana. The U.S. Army Corps of Engineers (USACE) New Orleans District is currently constructing multiple hurricane and storm damage risk-reduction projects to further buy down this risk.
Structural approaches, such as largescale levees and floodwalls, are what many people envision when considering flood risk management. Yet, the complex, dynamic environment of coastal Louisiana does not lend itself to a one-size-fits-all approach.
“An area’s unique geography, hydrology, sources for inundation, historical events, and population density must be carefully considered,” said Col. Cullen Jones, commander, New Orleans District. “The resulting recommended approach must be economically justified, environmentally acceptable, and technically feasible.”
As a result, a non-structural approach, such as elevating or flood-proofing structures or building smaller ring levees, can often be in the government’s best interest. Or perhaps, a hybrid approach that applies both structural and non-structural measures is the best option.
The New Orleans District is constructing three different flood management systems that will reduce risk associated with a 100-year storm surge, a surge that has a 1% chance of occurring in any given year. In south-central Louisiana, USACE has joined ongoing efforts by the state of Louisiana, parish governments, and the region’s levee district to complete the Morganza to the Gulf project, a structural system including 98 miles of levees, 22 navigable floodgates, and 23 environmental water control structures. This $6.5 billion system will reduce risk for approximately 200,000 residents and 50,000 structures.
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In southeast Louisiana, USACE is applying a hybrid structural and nonstructural approach for the West Shore Lake Pontchartrain hurricane and storm damage risk-reduction system. To reduce risk for the more densely populated St. John Parish, the system includes 18 miles of levees, floodwalls, and pump stations. In the adjacent St. James Parish, a nonstructural approach includes ring levees around smaller communities. Once complete, the $3 billion effort will reduce the risk for approximately 60,000 residents.
USACE is implementing a first-of-its-kind approach, combining non-structural floodplain management with environmental restoration projects, throughout a 4,700-square-mile project area in southwest Louisiana. The $1.5 billion project includes voluntary elevations or flood-proofing for up to 3,400 structures. The project’s ecosystem restoration includes 260,000 feet of shoreline protection, restoration of 14,000 acres of marsh and coastal wetland, and a reforestation project that includes planting seedling trees across another 1,413 acres.
“Congress and the administration made a commitment of providing the 100-year level of risk reduction for these communities,” said Jones. “We are delivering that commitment by applying the best science and engineering available to identify, design, and build the best system for each location.” AE
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