New Orleans Races to Dry Out Following Storms Like Francine

NEW ORLEANS — Hurricane Francine quickly gained strength before making landfall in Louisiana on Wednesday. The storm caused widespread power outages for hundreds of thousands, overwhelmed drainage systems, and left New Orleans grappling with significant rainfall.

Some areas reported over 7 inches of rain, surpassing the capacity of the city’s drainage infrastructure. In a dramatic rescue, an emergency room nurse saved a pickup truck driver just moments before rising waters submerged his vehicle.

Richard Campanella, a Tulane University professor and author of “Draining New Orleans,” explained that the region’s geography is a major factor during such storms. He noted that communities built on drained lowlands are susceptible to flooding when heavy rain returns these areas to their swamp-like conditions.

New Orleans has long been challenged by flooding issues. Residents were urged to conserve water to alleviate pressure on the sewer system, although drinking water supply remained intact. By the following day, officials reported success in draining the rainwater, a task that hinges on a complex system of pumps and canals crucial for keeping the city dry.

The city’s longstanding battle against flooding stems from its historical context. Hurricane Katrina underscored the catastrophic consequences of inadequate flood defenses when a levee breach inundated much of the city, leading to significant loss of life and immense flooding. In response, the federal government invested over $14 billion to create a comprehensive protection system comprising levees, pumps, and other flood management infrastructure.

The current design of this system was not significantly tested by Hurricane Francine. Early assessments indicated a storm surge of approximately 3 to 5 feet at Lake Pontchartrain, where the levee heights around the area exceed 16 feet. Ricky Boyett with the Army Corps of Engineers reassured the public that the levees held firm.

Yet, while barriers protect against storm surges, they can inadvertently trap rainfall within the city. The topography of New Orleans adds another layer to the flooding dilemma, as a significant portion of the city exists below sea level. Thus, gravity works against standard drainage systems that rely on natural downward flow.

To combat this issue, water must be pumped uphill into Lake Pontchartrain, leading north of the city. As a unique region molded by the Mississippi River, New Orleans was modified to manage flooding challenges, but this often means that sediment buildup from the river, which could naturally replenish land elevation, is curtailed. Author Boyce Upholt has remarked that the urban landscape is essentially sinking under its own weight.

During the heavy downpour brought by Francine, the city’s intricate network of pumps and drainage canals became essential. Generally, this system is designed to handle approximately an inch of rainfall in the first 90 minutes and an additional half-inch in subsequent hours.

Ghassan Korban, executive director of the Sewerage and Water Board of New Orleans, elaborated on the flow process, starting from catch basins that direct water into larger pipes and canals leading to pumping stations. However, when the system becomes overwhelmed, streets flood, and homes are at risk, as was witnessed in Lakeview during Francine’s passage.

Much of the city’s drainage infrastructure is aging, with some pumps dating back a century, despite continuous refurbishments. The drainage channels can accommodate large vehicles, and the city operates 24 pumping stations with 99 major pumps. However, many of these pumps rely on outdated electric frequencies which complicate modern power integration, representing a vulnerability in the system’s effectiveness.

When Hurricane Francine struck, some pumps experienced electrical disruptions, delaying the drainage process in certain areas. Over the years, improvements have been made, with new pumping stations added and miles of canals constructed post-flooding disasters like those in 1995 and significant management changes following a severe rainstorm in 2017.

At an event following the storm, Louisiana Governor Jeff Landry acknowledged that while the drainage infrastructure has improved, there remains more work to be done. Efforts are currently focused on identifying locations for additional pumps and enhancing power generation capabilities through collaboration with federal emergency officials.

This proactive approach aims to better predict the impact of rainfall and allocate necessary resources during such disasters. A particularly tricky scenario arises when storms catch forecasters off guard and linger over the city, producing substantial precipitation. Recent memory reminds us that some of the worst floods were not hurricanes but heavy rainstorms.

The implications of climate change further complicate these challenges, as warm air can hold more moisture, translating to increased storm intensity. Dominic Boyer from Rice University noted that Louisiana has encountered numerous events since Hurricane Katrina that have tested existing stormwater infrastructure, a trend that is likely to heighten in coming years.

As communities work to adapt to these chronic flooding challenges, experts and officials emphasize the importance of long-term planning and infrastructure resilience to meet the demands of more erratic weather patterns.

Source: Associated Press