Hurricane Katrina changed our thinking on a lot of things.
It made us look again at what’s the best way to evacuate the New Orleans metropolitan area within a couple of days. It caused us to think about better ways to station emergency resources so they can be brought into a storm-stricken area as quickly as possible.
In Jefferson Parish, it led to the construction of elevated housing for pump operators to stay in when a hurricane attacks. And Katrina just about drove a stake through the heart of slab-on-grade suburban housing.
Now, the experience of Katrina and the failure of the levee system are forcing us to look directly at water itself — not with an eye toward how to rid ourselves of it quickly, but how to live with it instead.
Understandably, we get nervous and impatient when water starts rising. After many of the floods that have occurred in the New Orleans area in recent decades, the usual refrain around town is about how long it seemed to take before somebody “turned the pumps on.”
But our desire to get all of the water out as quickly as possible may be creating more problems.
No one is saying storm water should be allowed to rise high enough to damage cars and low-sitting homes. But the Greater New Orleans Urban Water Plan, which was released in 2013, takes the view that we shouldn’t be so quick to get that water drained and pumped away, either.
David Waggonner, of Waggonner & Ball Architects, said the plan “signals a paradigm shift in water management, from a complete reliance on fighting water to finding ways to live with water.”
The problem with draining water away so fast is that it’s unnatural. Before concrete and drainage pumps, falling water soaked into the ground and nourished it. Pumping water away, on the other hand, dries out the underlying layers of soil, causing them to shrink.
The shrinkage leads to subsidence, which wreaks havoc on streets as well as the drainage pipes that lie beneath them.
Subsidence is not a new problem here. In parts of the metropolitan area in the 1970s, it led to the bizarre phenomenon of exploding homes. As foundations were torqued by severe subsidence, the hard pipes that connected homes to natural gas lines would sometimes crack and start leaking. Eventually something would ignite the leaking gas and an explosion would result.
That was another disaster that made us rethink the way we do things. Now, most homes are connected to natural gas via a flexible pipe instead of a rigid one.
Each time an area goes through another rain-and-drain cycle, with rainwater swelling the underlying soils only to see them shrink again as water is drained away, the net effect is for everything to fall lower and lower below sea level. As homes and streets sink, the chances of being flooded rise.
The water plan, which covers St. Bernard Parish and the east banks of Jefferson Parish and New Orleans, suggests various ways of holding rainwater instead of sucking it away. It shows a preference for reducing the amount of concrete lining local canals, for example.
The public works it proposes are massive, and no doubt expensive. It’s going to take a huge amount of political will to get them done.
Next week, at its national conference in Seattle, the American Planning Association will honor the Urban Water Plan with its 2015 National Planning Excellence Award for Environmental Planning.
It’s a great achievement. But the greater accomplishment will be the day when the plan finally becomes a reality.
Dennis Persica’s email address is firstname.lastname@example.org.