But in addition to all the technical pieces of the gates, there's other parts: the Corps' procedures and the supervisors and operating crews charged with following them. And here too, the possibility of risk is introduced.
The procedure for lowering the gates
In addition to preparing the sites before storm season, including the annual demonstration for the press in late May, the operators and supervisors are responsible for a number of tasks immediately in advance of a storm. They have to:
a) Remove the dogging pins which are supporting the gates in their stored position
b) Lower the gates into the trench via the hydraulic winches
c) Attempt to reinsert the dogging pins to determine if the gates are properly seated in the trench
d) If the dogging pins won't go in, the diving contractor Independent Divers (aka H.J. Merrihue) is supposed to remove the obstructions from the trench
e) Once the obstructions are removed, they then must lower the gates and try again to insert the dogging pins to secure the gates.
f) If the obstructions can't be removed, large sandbags are to be dropped in front of the gates (also called needles) that are not completely seated.
[Pictures and more details on the pins are available at my earlier entry, "The Pins."]
It is the insertion of the dogging pins that lets the operators and supervisors know the needles are properly placed to resist storm surge. The Corps Operations & Maintenance Manual for the gates says,
"If the dogging pins can be inserted when the gate is down, this will confirm that the notch in the sill is free from obstructions."
So if the dogging pins are not inserted completely, that would indicate an obstruction in the trench (or "notch" in Corps-ese) at that gate section. That would mean the gates are not contacting the inner surface of the trench fully - an unacceptable condition, as emphasized in the Corps' Manual :
"Because the notches in the sill structure provide the reaction for the bottom of the gates it is imperative that these notches be free of all foreign material and obstructions."
That is, the structures are designed to have surge force distributed in a certain way between the trench and the structure:
If the bottom of the gate is not in contact with the back of the trench, almost all the surge force is then going through the structure, with a large chunk falling against the unreinforced guide beams.
These forces from storm surge are huge. If they weren't, the sill under the trench at the London and Orleans sites wouldn't have sheet piling extending down 48 feet below the bottom of the canal and the structure wouldn't have pilings going down 100 feet below the canal bottom.
In sum, if the dogging pins are not completely inserted and locked, there's a problem in the trenches that has not been solved. That means the gates are not fully seated, and the city is placed at risk.
The procedure in practice - September 12, 2009
So how has this procedure worked during real events?
Gates have been closed for storm events on four occasions since the structures began construciton in 2006:
1) Hurricane Gustav in September, 2008 - 17th Street and London Avenue gates were closed
2) Hurricane Ike in September, 2008 - 17th Street and London Avenue gates were closed
3) September, 2009 - London Avenue gates were closed
4) Hurricane/Tropical Storm Ida in November, 2009 - London Avenue gates were closed
A fifth event, on December 12-13, 2009, should have triggered gate closures at London and 17th Street, but did not, likely due to a systemwide SCADA failure four days earlier during a very heavy rainstorm. Details are here. The Corps continues to refuse to release FOIA-requested emails from before, during, and after this event.
It's very difficult to get contemporaneous accounts of what happened at the sites during these events. The Corps can put out press releases, and the media can do one- or two-minute stand-up reports standing hundreds of feet away, but actually knowing what happened in detail is tough. In addition to my FOIA request for the December, 2009 emails, the Corps is continuing to refuse release of emails relating to the November, 2009 London Avenue closure during Ida.
Fortunately, the Corps themselves dispatched someone to take pictures during at least one of these events. On September 12, 2009, heavy rains hit the New Orleans area. As a result of coincident rising lake levels, the gates were closed starting around 6 PM.
There weren't a lot of pictures from that Corps photographer, but one only needs a single good one.
Here is that one:
This photo was taken on September 12, 2009, after the gates were closed. It's the area inside the red square that should concern everyone in the New Orleans metro. Let's zoom in:
This shows that Corps operators and supervisors apparently left at least four dogging pins uninserted into the gates, a major violation of procedure. Those pins appear to be on needles 4, 5, 7, and 8. There are 11 needles in total.
The Times-Picayune also sent a photographer, Scott Threlkeld, out to London Avenue that afternoon to photograph the gate closing process. Mr. Threlkeld snapped two photos whch might partially confirm the pins' status.
The caption on the first (linked here) reads, "Randy Faherty of the U.S. Army Corps of Engineers shoves in a steel pin to lock a lowered flood gate in place Saturday, September 12, 2009, at the London Avenue Outfall Canal structure."
The caption on the second (linked here) reads, "Randy Faherty of the U.S. Army Corps of Engineers checks the water level after dropping the flood gates Saturday, September 12, 2009, at the London Avenue Outfall Canal structure."
I believe the captions on these photos are likely wrong. I do not believe the operator is checking the water level or shoving in a pin. I believe he is trying to figure out why a pin won't go in. And I believe that pin - on needle #8 - is the same one visible out of place in the deep background inside the blue frame in the Corps photo above. It appears Corps supervisors allowed the needles to remain unsecured.
So multiple gates were very likely not seated properly, due to obstructions in the trench. In that case, the Corps was supposed to have called Independent Divers (who are supposed to be on standby during storm events) to clear the obstructions. Let's take a look at the task orders given to Independent Divers (aka H.J. Merrihue) around September 12, 2009:
Task order 60
August 24, 2009
"For an emergency Dive required on 22 Aug 2009 due to a seal blow-out on the dewatering needles. Divers will be directed as needed."
The location of this task order's work is unknown. However, it is definitely not the outfall canals, since there are no dewatering needles at those sites. It was likely one of the Corps' locks.
Task order 61
August 31, 2009
"4 Man dive team required at Port Allen Lock for rewatering Process."
The Port Allen lock is across the Mississippi River from Baton Rouge.
London Avenue gates closed
September 12-14, 2009
Task order 62
September 24, 2009
"Dive contractor is required to perform magnetometer surveys to locate unknown sunken objects."Even without a location, this is clearly not for trench cleanouts.
London Avenue gates closed
Hurricane/Tropical Storm Ida
November 9-11, 2009
Task order 63
November 18, 2009
"Four Man Dive team to investigate loud noise at gates at Algiers Lock.
The Algiers Lock is across the Mississippi River from St Bernard Parish.
As we can see, at least according to the contract record, Independent Divers was not summoned by Corps supervisors for trench cleaning during the time of the September London Avenue gate closure, even through photos seem to show an inability to close multiple gate sections. It also doesn't appear they made it out any time between that September event and the November London Avenue gate closure. This appears to be another violation of the Corps' own procedure.
Frankly, it appears there was little diving activity at any of the outfall canals through the 2009 hurricane season. Here's all the confirmed task orders for those sites during 2009:
Task order 54
May 18, 2009
"PROVIDE DIVING SERVICES TO CLEAR DEBRIS FROM GATE SILLS WITH THE USE OF A WATER JET PUMP, WITH GENERAL GATE INSPECTIONS REQUIRED AT EACH OF THE THREE LOCATIONS.
LOCATION: 17TH ST. CANAL, ORLEANS AVE. CANAL, & LONDON AVE. CANAL FLOODGATES."
This is the annual cleanout of the trenches before hurricane season
Task order 56
June 3, 2009
"Inspect the bridge pumps 1 and 6 and their foundations and remove any existing obstructions.This was diving associated with the bridge pump repair work at 17th Street.
The dive work is estimated to take approximately five (5) hours.
LOCATION: 17th Street Canal
WORK TO START AT HRS: 0800 HOURS, 04 JUNE 2009."
Task order 59
August 17, 2009
"Emergency Dive at 17th St Canal Floodgate to clear debris from gates sills with the use of a water jet pump, with general gate inspections required at each of the two locations. Verbal NTP was issued on Aug 17, 2009."
This would appear to be preparation associated with Tropical Storm Claudette. Claudette was a minor threat that formed west of Tampa on August 16th and dissipated the next morning as its remnants came ashore in Alabama. By the time the Corps issued the verbal notice to proceed ("NTP") on the 17th, the storm was already past. Tides ran about a foot above normal.
Since the gates at the London Avenue canal, with its lower Safe Water Level, would be closed before 17th Street, it seems unlikely this task order only applied to 17th Street. The mention of "two locations" at the end of the description hints at the possibility that divers were supposed to also visit London, but it's impossible to know whether that occurred. It could simply refer to obstructions under two separate gate sections at 17th Street. In any case, the inability of the operators to completely secure multiple gate sections at London Avenue on September 12th makes the question moot. The London Avenue trenches do not appear to have been clear on the 12th for a real storm event.
Those three task orders are it for 2009. It does not appear the divers were regularly cleaning out the trenches at all during 2009, despite the Corps Operations & Maintenance Manual calling for the gates to be tested every three weeks during hurricane season:
"Once hurricane season has started, certain activities should be performed at regular intervals so that issues that could potentially interfere with the operation of the gates can be identified and addressed without the threat of an approaching storm.
Operation of the gates should be performed every three (3) weeks. Gate operation should be performed in the same manner as described in paragraph 18.104.22.168 for the check of gate operation prior to the hurricane season. A diver should be brought in to inspect and assist in removing obstructions if they are encountered."
It seems unlikely, if the gates are being tested every three weeks, that there would be no call for removal of obstructions on any of the gates across all three sites. City pumps are run often during the rainy New Orleans summer, sending all sorts of debris down the canals. Some of that debris would inevitably get caught in the trenches. This near complete lack of diving activity brings into question if the gates are truly being tested every three weeks during hurricane season, and if not, why?
It would have been Corps supervisory personnel in the Operations Division making these decisions regarding divers.
So we've got gates not being secured and divers not being called in to clean the trenches. What else happened - or didn't happen - during that September 2009 event?
The 2009 operations manual says if the obstructions in the trenches cannot be dislodged by the divers, massive sandbags are supposed to be dropped by the on-site rental crane in front of the needle where the obstruction lies. This is supposed to close the gap along the trench. Just for reference, here's the sandbags at the London Avenue canal earlier in 2010:
I previously established that this Google satellite shot was from the spring of 2010.
Zooming into the area inside the red box:
On the ground shots around the same time as the Google shot:
I can't speak to whether those sandbags were placed or not, or if they were even on site. However, the lack of photographic evidence both on September 12th (from two independent sources) as well as no Corps photos of sandbags getting removed from the water on September 14th certainly leads one to believe that no sandbags were placed. That's a third violation of procedure.
1) Gates unpinned
2) Divers not summoned
3) Sandbags not placed
The Corps "responds"
I repeatedly asked for comment on this story from the Corps' New Orleans District Public Affairs office. Here's what they sent me:
"Mr. McBride -- The gates do not have to be pinned to be sealed. Everything worked as it should.
Ken [Holder, Chief, Public Affairs, Corps New Orleans District]"
This semi-confirms the gates were unpinned last September, and certainly doesn't deny it. The mention of them being sealed is not relevant, because the seals at London Avenure are just for show. The importance of pinning is in effective transfer of surge forces to the foundation, not sealing, which is made abundantly clear in the Corps' own Operations & Maintenance Manual for the gates.
So, it looks pretty bad. Compared to other storm events, the September, 2009 closure was a minor event. The lake never got above about 3 feet, and that happened just two hours after the gates were closed on September 12th. Such an event would act as a real world drill, so you'd think the Corps supervisors would try to get everything right with a bit of the pressure off. That way, when the Big One comes with its Big Pressure, they'd be able to handle it. Instead, it appears they viewed this as a nothing event when key parts of procedure could be skipped, which makes one wonder what's happening the rest of the time, and what will happen when the Big One hits.
Next up: How the pumps performed during this event.
Karen Gadbois of The Lens, and Molly Peterson of Southern California Public Radio contributed to this report.