User:Johnherrick

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[[I was asked to review an article Mr. I.VanHeerden wrote about MRGO and the flooding of New Orleans; below is an annotated version:]]

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Extensive history and our storm-surge models produced long before Katrina show insufficiencies in many different areas, each a disaster waiting to happen, even without actual failures such as occurred during Katrina. With every levee holding intact and doing its job as built, parts or essentially all of New Orleans will still go under when a slow-moving major hurricane following any one of numerous scenarios hits the region. The details of the surge\ flooding disaster would depend only on the strength, forward speed, and direction of approach of the storm.

Very good

With Katrina, the ADCIRC surge models pinpointed the primary problem as the levees along the Intracoastal Waterway and the Industrial Canal, which would be overtopped by the storm surge rolling in from the Breton and Chandeleur sounds

So far so good: yes, models predicted that a “major” hurricane would overtop the levees; the walls were not going to protect New Orleans: no news there, no science either.

and pushed up the Funnel, a feature shaped by the waterway and another shipping channel, the Mississippi River-Gulf Outlet. Image:I.Van Heerden, MRGO,p4.jpg

This is true only if water were to run west as his arrow points. This is not true if, as happened, the storm surge came southwest as shown in the Times Picayune. Image:Storm surge 5 AM.jpg

The water will not go west as the arrow points because the source is further north. Besides, look closely at the map above, where is MRGO? It is there, and to scale, but it is an insignificant feature in the overall picture. The canal MRGO could be very deep and big, but it is under 14 feet of water (water over the entire area!), thus it has no hydraulic effect.

MR-GO, as it is always labeled (sarcastically pronounced "Mister Go"),

“sarcastically pronounced”?

was built by the Corps to provide shipping with a straight shot into the Gulf of Mexico, a 76-mile route

Interesting that, from the Industrial canal to the Gulf it is 43 miles long, where is the other 33 miles?

that cuts 40 miles off the trip down the winding channel of the Mississippi River. This route was originally authorized to be 650 feet wide at the surface, 500 feet at the bottom, 36 feet deep. It required removing more dirt than did the Panama Canal—hard to believe—

This amount was true, however it was dirt (not rock as in the Panama Canal) and was moved using pumps: not blasting powder, manpower, steam shovels and trains.

and from the earliest planning stages in the late 1950s it was challenged by a host of opponents— including the Corps, because it did not remotely satisfy any of its cost-benefit analyses. Keep trying, Congress replied. The Department of the Interior stated that "excavation could result in major ecological change with widespread and severe ecological consequences."

If there was such great and all encompassing opposition, why did it get built?

That's exactly what has happened. As a result of erosion, the channel in some stretches is now three or four times as wide as the design specification.

NOT TRUE. Three times the 650-foot “design specification” would be 1950 feet, four times would be 2600 feet. The canal and upper flooded areas is never 1950 feet wide, much less 2600 feet. The canal itself is not as wide as the aerials show (no wider than 1800 feet, and it averages 1352 feet). Due to the subsidence of the area (approximately 4 feet since the canal was built) the land to the east of the canal, which was just above sea level, is now under water. This is not a cause of MRGO.

Contiguous marshlands have been severely damaged, if not ruined. The canal feeds saltwater directly from the Gulf of Mexico into freshwater marshes and swamps and has effectively killed thousands of acres of wetlands, which are now just open water marked by the trunks of the odd dead cypress trees.

The “contiguous marshlands have been severely damaged, if not ruined” due to the subsidence of the area (approximately 4 feet since the canal was built) the land to the east of the canal, which was just above sea level, is now under water. This is not a cause of MRGO.

As I’ll discuss in detail later, levees protected by healthy marshes are much less likely to fail.

OK, so stop the subsidence! My belief is that some of the subsidence is due to pumping oil and gas from the area, and some is just natural compaction of the soils – the soils in the area were deposited there by the Mississippi River. Such hydraulically placed soils are not compact, and are subject to natural compaction over the years.

Simply put, MR-GO has devastated the

Simply put, MRGO has not done anything of the sort!

81

1. Storm surge vulnerability a. Not true i. The storm surge of Katrina saw the levees around MRGO as a hindrance, not a help, it stopped the storm surge from moving inland until 5 AM according to the Times Picayune.

2. Extensive environmental damage a. Not true i. The environmental damage is being caused by subsidence, not erosion. ii. The canal does not impact Orleans and Plaquemines Parishes: Plaquemines Parish is 9 miles away!

No wonder it's also called Storm Surge Alley, or Hurricane Alley.

Only by the uninformed.

Shut it down! Rebuild those marshes! Almost everyone agrees,

Closing the canal (filling it in and building a marsh in the area of the canal) would not help anything, the entire area is subsiding. Building a 25 foot levee would help though.

but it still hasn't happened, even though only five ships a day, maximum, use the thing. Following Hurricane Ivan in 2004 the Corps even spent $17 million dredging it for the sole benefit of those lonely ships. Generally, annual maintenance costs vary from $ 13 million to $3 7 million.

One good reason to stop maintenance though, if true.

The impact on the marshes is one problem with MR-GO. The second, more immediate problem, is its levees, because storm surge pushing across shallow Lake Borgne from the east is constrained by these MR-GO levees to the south and, to the north, by the longstanding levees of the Intracoastal Waterway.

This is one reason the flooding did not occur from other Hurricanes!

Initially ten or more miles apart, these two channels meet, and when they do the water building between their levees is squeezed into a single channel—the Funnel—only 260 yards wide, constrained by levees 14 feet to 16 feet high. Surge warrior Hassan Mashriqui has studied this phenomenon with zealous attention. His series of surge hydrographs and other velocity plots demonstrate without a doubt just how bad the "funnel effect" is right here. In concert with the denuded marshes, it could increase the local storm surge hitting the Intracoastal Waterway by 20 percent to 40 percent—a "critical and fundamental flaw" in the system, in Mashriqui's phrase. I remember the scene when he and Paul Kemp asked me to look at this data. They knew it was critically important, and so did I, because the levee designs and heights out here did not take this funnel effect into account. They weren't high or strong enough.

The area cannot act as a funnel if the water comes as it did from the northeast, parallel to the levee to the north and perpendicular to MRGO!!!!!

We have to get this news out, I said. Mashriqui and Paul started with a poster at a conference, and then we sought every other possible venue to warn people about this inherent weakness in the levee system. In January 2005, Walter Brooks, executive director of the Regional Planning Commission of the New Orleans Metropolitan Area, asked me to give a talk about hurricane surges and vulnerabilities at their offices in New Orleans. The surge amplification caused by the Funnel was a featured point, and during the ensuing discussions I was asked if we at LSU could come up with a conceptual plan to build a structure to protect the area. I said yes, of course. Jefferson Parish president Aaron Broussard said they couldn't wait for the

Chicken Little said that the “sky is falling”, that did not make it right either.

82 Corps, that the parishes would have to fund this effort themselves. The two Corps officials who were there said the Corps could also develop plans, but I got the impression that these parish presidents meant business. Walter Brooks asked me to return and give a longer talk that would be taped and aired on local cable TV. I was going to be overseas, so I suggested that Mashriqui give the talk. The Funnel was really his baby, anyway. He did a great job, and right before Ka-trina struck we were getting ready to draw up a proposal for the conceptual planning study. The Funnel is six miles long. To the west, it—and the water in it—"T" into the Industrial Canal. It's hard to believe, if we step back to think about it. The federal powers that be had inadvertently designed an excellent storm-surge delivery system—nothing less—to bring this mass of water with a simply tremendous load—potential energy— right into the middle of New Orleans.

NOT TRUE

If during any given storm the levees along the Intracoastal Waterway and MR-GO have not already been overtopped—or even if they have been, in a big storm like Katrina—something has to give at this critical intersection, and if the levees are anything less than optimal, it's not going to be the water.

It did not act as a funnel, if so, the water would have overtopped much earlier.

That's what happened on the Monday morning when Katrina struck. At 6:10 A.M. the hurricane made landfall at the small town of Buras

Actually Empire was the center where Katrina struck.

in the farthest reach of the Mississippi Delta. Katrina had weakened considerably overnight. By dawn, she was a minimal Cat 3 storm, with highest winds of 112 mph.

Actually the winds were 20 miles per hour at the center in Empire and 135 miles per hour well to the east.

Buras and vicinity were nevertheless devastated, of course.

Buras was devastated by the storm surge both from the southwest when the levees failed adjacent to the pump station and from the north when the levees failed adjacent to another pump station, neither had anything to do with the MRGO canal.

Forty miles to the north, where the winds were still a mere 60 mph, the first flooding of residential areas in the greater New Orleans area had already begun. The storm surge building on Lake Borgne east of New Orleans would peak at 18 feet at about 7:00 a.m., but several hours earlier the huge waves on top of the surge, driven by the winds from the east, made fairly quick work of certain stretches of the MR-GO levees, which were overwhelmed and in some cases destroyed. Water poured into the lower areas of the bowl between the Intracoastal Waterway and the Mississippi River, including Chalmette, Meraux, and Violet, with the Lower Ninth Ward farther to the west in serious jeopardy.

OK, so eliminating MRGO would accomplish what? No mention of a “funnel” here: Lake Borgne overflowed from the northeast over the MRGO levee, and filled the area between the levees.

At about 6:30 a.m., the surge of fourteen feet to seventeen feet in

83 the Funnel proper—the confluence of MR-GO and the Intracoastal Waterway—overtopped the levees on both sides.

What would a marsh have accomplished? With 14 to 17 feet of water over it, MRGO and the marsh are not even a factor.

To the south this water poured into the communities that were already taking on water through the MR-GO breaches, now including the Lower Ninth Ward. To the north it poured into the neighborhoods in the adjacent bowl in Orleans Parish, between the Intracoastal Canal and Lake Pontchartrain. (Some of these neighborhoods had already been taking in some water from the earliest of all the breaches—between 4:30 a.m. and 5:00 a.m.—at the junction of the CSX Railroad and the northern arm of the Industrial Canal, right next to Interstate 10. The metal gates where the railroad tracks pass through the I wall of the levee were not working, apparently because of a prior derailment, and the pathetic sandbags in their stead gave way early on both sides of the canal. We know this because a nearby gauge measuring the water level recorded a rapid drop from nine feet to four to five feet above sea level.

What does a derailment and “pathetic” sandbags have to do with MRGO?

Water poured into the Orleans East bowl and the Gentilly section of the Orleans Metro Bowl to the west. While this breach was not a huge flood maker, it would have frightened local residents and, we can hope, alerted them to head for high ground—that is, the rooftops.)

Gentilly was flooded by the London Ave. Canal breach, on the opposite side from MRGO!

At about 6:50 a.m., the surge coming through the Funnel hit the T at the Industrial Canal; some of this water was forced to the right, or north, and poured into Lake Pontchartrain, which was then ten feet lower than the surge. The rest was forced to the left, or south, where it was blocked by the closed locks that connect the waterway and the Mississippi River. (The locks were closed in order to separate the surge in the river from elsewhere.) As Mashriqui's model run had predicted, the levees along both sides of the Industrial Canal, from the river to the lake (a distance of five miles), were now overtopped. Water poured into the two bowls to the east, which were already taking on water, and now also into the bowl to the west—the Orleans Metro Bowl. Alas, this overtopping did not relieve enough of the pressure on the flood walls. At 7:45 a.m., give or take not many minutes, two dif-ferent sections of the levee along the eastern side of the southern end of the Industrial Canal—a total of about four hundred yards—

Image:I.Van Heerden, MRGO,p6.jpg

The “I” walls for the most part were not overtopped as shown, but gave way much sooner due to undermining. This had nothing to do with MRGO.

286 New Orleans area? The Corps's district office says it will have everything back to pre-Katrina levels by June 1. I'm not sure what this means, because the whole levee system is compromised.

Two areas, 1. The three canals (17th Street, Orleans, and London Avenue). 2. The Lake Ponchartrain and perimeter levees, including MRGO. It will not be back at pre-Katrina surge-protection levels. The heights of the levees may be as they were, but height, as we saw with the catastrophic failure of the London Avenue and 17th Street levees, is not the only factor in their survival. The three canals now have gates, eliminating the problems in those canals.

The Corps says it will have the MR-GO levees rebuilt by June. With what? There are no sources of good material anywhere near those destroyed levee sites. Site inspections by Team Louisiana have shown that the contractors, in many areas, are using a sand base material for the repair. They appear to be scraping up the remnants of the old levees and trying to use this material, plus some they have barged in. Sand is porous and highly permeable, and it lends itself to dangerous seeps—not exactly the material of choice for levees.

All of the levees are made of this sand – as he says - the remnants are sand. If protected, sand is acceptable; the problems mostly were where the sand was transitioned to the pump areas etc. This is being armored.

The contractors themselves are concerned; their field staff told us they are not getting the support or supervision they expected from the Corps.

Contractors wanting MORE supervision?

The Berkeley levee warriors and the ASCE team have been quite vocal in the media about these questionable repairs. Are they a strong pointer to the future? I sure hope not. Moreover, the progress out east has been painfully slow. Unless drastic changes are made, these levees will not be fully returned to the pre-Katrina heights, even using the unsuitable materials.

Wrong, they are done.

There will be no armoring at all. Any wave field that develops in Lake Borgne with an east wind will start to erode these levees instantly.

Wrong, armoring is happening all along the areas where it is most in need.

At the other side of the metropolitan region, way out west at the border of Jefferson Parish and St. Charles Parish, a levee I haven't mentioned because it was not a problem during Katrina could be a terrible problem with the next storm. For a stretch of about 150 feet, the flood wall sections have sunk about 6 inches and are offset one from the next by a few inches at the top. This structure needs help, and fast. At the Industrial Canal above the Lower Ninth Ward, the I wall has been removed and will be replaced by an inverted T wall with batter piles. This is good, because it's a far more robust design. The Corps understands that the whole levee wall was compromised in this area. The three breaches on the infamous drainage

All of the levees have sunk 2 feet or more. This is much more of a problem. The city cannot be protected from all storms with the money available. It would take many more billions to protect the city from a Category 5 storm. Are the remaining residents willing to fund this? The nation can help, but the residents must know that they are at risk. Only houses built on stilts will be OK in the long run, but most are not willing to build that way. Those who just repair are putting their “heads in the noose” for the next storm. MRGO does not do any damage as it sits. It is not causing more environmental damage and is of no consequence when the storm surge comes from the northeast. If there is no advantage to it, letting it fill in naturally will work. Spending a billion to fill it and create a marsh will not accomplish anything, that money would be better spent elsewhere. Johnherrick