Water Everywhere

When it comes to keeping it out, we can definitely do better.
Lawrence Powell, The Accidental City; The Greater New Orleans Urban Water Plan; FEMA
* National Flood Insurance Program

In the spring of 1719, as Bienville was managing the nascent settlement of New Orleans, the Mississippi River overflowed its banks and saturated his project for months. In response, he oversaw the construction of the first levees along the river, thus beginning our region’s centuries-long and still ongoing tension between its greatest resource and its intractable nemesis: water.

The city’s location between the Mississippi River and Lake Pontchartrain was chosen specifically for its advantages in commerce and defense. In nearly every other respect, however, the management of water has been one of the defining and most difficult efforts of engineers, political leaders, and residents along and around the river’s crescent. We struggle constantly with water from the river, from the lake, and from the sky, with effects ranging from the inconvenient to the devastating.

Indeed, since 1978, approximately $15.2 billion in claims from the National Flood Insurance Program (NFIP) have been paid to property owners in metropolitan New Orleans. That’s 29 percent of all NFIP claims paid nationwide during that period to a region with less than one-third of 1 percent of the country’s population, obviously in large part as a result of damage inflicted from Hurricane Katrina.

In the 10 years since Katrina, the U.S. Army Corps of Engineers has engaged in an unprecedented re-fortification of the region. The upgrades to our storm surge risk reduction system, consisting of new or upgraded levees, flood gates, pumps and other infrastructure, provide 350 miles of enhanced storm protection at a cost of roughly $14.5 billion. These efforts have significantly improved our area’s level of vulnerability from even relatively severe storms, as evidenced in the revised flood zone maps, released after years of protracted discussions between local leaders and FEMA.

On the other hand, the New Orleans area receives an average of 62 inches of rain every year, and when storm water appears in large quantities in short periods of time, our system of drains and pumps are often not up to the formidable task of removing it. The results of localized flooding have long plagued us.

In 2010, the Department of Housing and Urban Development funded an effort to reimagine how the New Orleans region lives with water, focusing primarily on how to manage storm water more holistically and efficiently. The result, the Greater New Orleans Urban Water Plan, provides some fascinating data about water in our area, the consequences of how we have controlled it, and proposals for thinking and acting differently.

For example, our primary approach to removing storm water has been to “pave, pipe and pump,” through a network of drains and canals. Our system’s pumping capacity of 59,218 cubic feet per second is often inadequate to avoid temporary but significant flooding, and more importantly, it deprives our ground of much of the water it needs and can absorb naturally. In a natural landscape, the ground can and should absorb roughly half of rainwater; instead, it currently is able to absorb about 15 percent.

As the plan points out, this deprivation has caused tremendous levels of subsidence—by some estimates, portions of Kenner and eastern New Orleans have lost about 10 feet in elevation over the past 50 years. And, of course, it leads to an uphill and virtually futile battle to maintain road quality and solid housing foundations. All in all, the plan projects that in the next 50 years, the current approach to managing storm water will result in over $10 billion in costs associated with flooding and subsidence alone.

The plan’s recommendations—a portfolio of interrelated projects consisting of repurposing canals, developing large storm water retention areas, retrofitting streetscapes, and building requirements for new properties—is ambitious and expensive, but also forward-thinking. At a time when we hear and read so much about sea level rise, the state’s $50 billion Coastal Master Plan, and the threats of storms, it is worth our effort to do what we can within our floodwalls to cope with a daily reality that will not improve on its own.
 



Robert Edgecombe is an urban planner and consultant at GCR Inc. He advises a wide range of clients on market conditions, recovery strategies, and demographic and economic trends.

 


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