Floods in New Orleans: What Hath MRGO Wrought
Some background to illustrate a point relevent to my previous post.
New Orleans hundreds of years of history has multiple examples of floods from semi-tropical downpours, hurricanes, and levee failures.
What happened in 2005 was radically different.
Comparison of very close to the same location, more than a century and a quarter apart:
Canal Street at Claiborne Avenue, Great Flood of 1871. Calf-deep water.
Claiborne Avenue near Canal Street, after the Katrina levee failures. Chest deep water.
Something seems to be different now. Apparently the single most important difference is a Canal called MRGO.
Some may be surprised to learn that Katrina was not the worst hurricane to hit New Orleans. That distinction still belongs to the Great New Orleans Hurricane of 1915. (Note: I am talking about actual hurricane winds within the City limits. Camile had a higher wind speed and Katrina was a larger in area, but both hit with their greatest force to the east of the city, with less of their force here.)
Katrina hit the city with category 2 winds; the Great Storm of 1915 battered it at category 4.
One of the worst hurricane hits of the 20th century, wind destruction was widespread, with pretty much every church steeple in town being either severely damaged or completely knocked down.
Coastal areas south and east of the city suffered storm surge flooding, but New Orleans is not on the coast and thus did not experience surge.
The city's new water drainage pumping stations at first showed their worth; even though the storm was more intense than the most recent previous hurricane the flooding was less severe. However electric lines were downed throughout the area, cutting off power to the pumps when the storm was at its worst. Low lying parts of Mid-City flooded, with the waters not drained for days until power could be restored.
Despite the destruction, there is a certain element of self-congratulation in contemporary accounts. The city took the worst nature could throw at it and survived. Electric streetcar lines were back running within the week. Things that failed were taken as valuable lessons for the future: The railway over the Rigoletts east of the city flooded? The rail line must be elevated. The pumps failed when the electric lines blew down? Henceforth all the pumping stations would be supplied with back up diesel generators.
In 1915, the waters in Mid-City were below the hubs of the wagon wheels. In that same neighborhood in 2005, floodlines were left above the roofs of SUVs.
So why were things so much worse with Katrina in 2005?
What happened to New Orleans August 2005 should be understood as a pair of related but distinct disasters: 1)Hurricane Katrina 2)the failure of the Federal levee & flood control system. Hurricane Katrina was certainly destructive, but by far the less damaging of the two disasters.
Church damaged by Hurricane Katrina, Magazine Street.
Church damaged by the levee failures, Florida Avenue.
The role of the catastrophic design flaws of the US Army Corps of Engineers levess has been understood since November 2005 (just long enough after the disaster for most of the mass media to pay little attention).
Okay, so the badly built levees and floodwalls failed in 2005. But they didn't exist at all in 1915. What gives?
The MRGO Canal was suspected of being a major factor in the flooding early on, the exact role has only become clear more recently.
Asked how much of the 2005 Metro New Orleans flooding was the result of MRGO, the authors of "Catastrophe in the Making: The Engineering of Katrina and the Disasters of Tomorrow" came to the startling conclusion "almost all of it".
Without MRGO, storm surge from the deep Gulf wouldn't have been funneled into the heart of the city.
Without MRGO, there would have still been a substantial wetlands barrier which would have made the rise in water level of Lake Pontchartrain much less severe.
Without MRGO, even the lousy levees we had pre-K would have been enough to protect the city, and the only water we would have had to worry about was what fell as rain.
In short:
There's a difference between a flood that gets your feet wet in the street
And one that drowns you in your attic.
Heck of a job, MRGO.
New Orleans hundreds of years of history has multiple examples of floods from semi-tropical downpours, hurricanes, and levee failures.
What happened in 2005 was radically different.
Comparison of very close to the same location, more than a century and a quarter apart:
Canal Street at Claiborne Avenue, Great Flood of 1871. Calf-deep water.
Claiborne Avenue near Canal Street, after the Katrina levee failures. Chest deep water.
Something seems to be different now. Apparently the single most important difference is a Canal called MRGO.
Some may be surprised to learn that Katrina was not the worst hurricane to hit New Orleans. That distinction still belongs to the Great New Orleans Hurricane of 1915. (Note: I am talking about actual hurricane winds within the City limits. Camile had a higher wind speed and Katrina was a larger in area, but both hit with their greatest force to the east of the city, with less of their force here.)
Katrina hit the city with category 2 winds; the Great Storm of 1915 battered it at category 4.
One of the worst hurricane hits of the 20th century, wind destruction was widespread, with pretty much every church steeple in town being either severely damaged or completely knocked down.
Coastal areas south and east of the city suffered storm surge flooding, but New Orleans is not on the coast and thus did not experience surge.
The city's new water drainage pumping stations at first showed their worth; even though the storm was more intense than the most recent previous hurricane the flooding was less severe. However electric lines were downed throughout the area, cutting off power to the pumps when the storm was at its worst. Low lying parts of Mid-City flooded, with the waters not drained for days until power could be restored.
Despite the destruction, there is a certain element of self-congratulation in contemporary accounts. The city took the worst nature could throw at it and survived. Electric streetcar lines were back running within the week. Things that failed were taken as valuable lessons for the future: The railway over the Rigoletts east of the city flooded? The rail line must be elevated. The pumps failed when the electric lines blew down? Henceforth all the pumping stations would be supplied with back up diesel generators.
In 1915, the waters in Mid-City were below the hubs of the wagon wheels. In that same neighborhood in 2005, floodlines were left above the roofs of SUVs.
So why were things so much worse with Katrina in 2005?
What happened to New Orleans August 2005 should be understood as a pair of related but distinct disasters: 1)Hurricane Katrina 2)the failure of the Federal levee & flood control system. Hurricane Katrina was certainly destructive, but by far the less damaging of the two disasters.
Church damaged by Hurricane Katrina, Magazine Street.
Church damaged by the levee failures, Florida Avenue.
The role of the catastrophic design flaws of the US Army Corps of Engineers levess has been understood since November 2005 (just long enough after the disaster for most of the mass media to pay little attention).
Okay, so the badly built levees and floodwalls failed in 2005. But they didn't exist at all in 1915. What gives?
The MRGO Canal was suspected of being a major factor in the flooding early on, the exact role has only become clear more recently.
Asked how much of the 2005 Metro New Orleans flooding was the result of MRGO, the authors of "Catastrophe in the Making: The Engineering of Katrina and the Disasters of Tomorrow" came to the startling conclusion "almost all of it".
Without MRGO, storm surge from the deep Gulf wouldn't have been funneled into the heart of the city.
Without MRGO, there would have still been a substantial wetlands barrier which would have made the rise in water level of Lake Pontchartrain much less severe.
Without MRGO, even the lousy levees we had pre-K would have been enough to protect the city, and the only water we would have had to worry about was what fell as rain.
In short:
There's a difference between a flood that gets your feet wet in the street
And one that drowns you in your attic.
Heck of a job, MRGO.