Fix the pumps

Thursday, October 15, 2009

Pennywise Part 4

Previously: Part 1 Part 2 Part 3

[Pardon the copying of verbiage from Parts 1, 2 and 3 at the beginning of this part. You can scroll down past the main list of 13 features to see the new content]

The largest refrain from those in support of Option 2, which is everyone but the Corps, is that effective flood protection is better than cheap flood protection. Supporters of Option 2 say it is just plain better than Option 1, a position even the Corps agrees with in a technical evaluation report mandated by Congress. The problem New Orleans and the surrounding area faces is that the Corps is cheaping out and going for Option 1 over Option 2, which is exactly what the Corps chose to do just months after Katrina, even though they believed it would only take another $190 million to do Option 2. Admittedly, it may have cost a little more to do Option 2, but based on the facts at the time - and what was passed up the chain to the White House and Congress - the Corps CHOSE to do Option 1 to save $190 million, and drafted the authorization and appropriation language to match it. The cheaping out began a long time ago.

However, I would go further and say that the Corps is cheaping out even on how they are planning to build Option 1. I believe they are deliberately lowballing the Option 1 estimate in order to make it look like the only way to go. They are doing this through a combination of shifting some features to future Option 2 and simply not building other features. If they didn't, it would be revealed that even Option 1 - if it was truly to be built correctly and be adaptable to Option 2 - cannot be built for the $804 million the Corps told Congress to give it.

In part 1 of this series, I introduced the various flavors and features of the Option 1 pump stations as they are laid out in three primary sources:

a) The 2009 Black and Veatch report
b) The 2009 Congressional Cost Report
c) A presentation given by the Corps to the SLFPA-E (east bank levee authority) on October 1, 2009.

See that earlier post for an explanation of the three flavors of Option 1 from the 2009 B&V report.

For reference, here's the description from the Cost Report:
"Pumping Plant - The pumping stations include the pumping station building and equipment, intake wet well, discharge section, canal transitions, generators with enclosures, a tank farm, and all the ancillary systems required for a fully functional facility. A cofferdam is required for the contruction of the pumping station. A temporary bypass may also be required to route canal flows around the cofferdam during construction."

And here are the renderings from the October 1, 2009 presentation. First, the plan for Option 1:

and the plan for Option 2:

The list of pump station features from the 2009 B&V report is:

1) Includes Floodwall/Levee Upgrades
2) Includes Gated Bypass
3) Canal Transitions
4) Deepened Sill
5) Formed Suction Intake
6) All Electric Pumps
7) Pump Station Sized for Future Pump Capacity
8) Pump Capacity Sized for Future Pump Capacity
9) Fuel Storage and Generator Sized for Future Capacity
10) Includes Siphon Recovery
11) Includes Breakwater
12) Stilling Basin at Discharge
13) Removal of ICS Facilities

As I've noted above, we've already covered the first nine features. In this post we'll move on to the last 4...

10) Includes siphon recovery

Siphon recovery is an arrangement of the discharges of the pumps that allows recovery of energy of the water as it exits to the lake. It is a big hump in the discharge tube that, once water is flowing through it, sets up a siphon that knocks the required head of the pumps down to the difference between the canal and lake levels (along with losses through the station). It also acts as a backflow prevention mechanism by virtue of the bottom of the siphon peak being above the lake surge level. Note, however, this is not as reliable a backflow preventer as a flapper gate or some other positive closing mechanism.

Here's a detail from the October 1, 2009 SLFPA-E presentation showing the siphon recovery section:

All of the options include siphon recovery, so there's really no discussion about other options here.

On a related note, though, it is imperative these stations include two forms of backflow prevention, per governing Corps standards. For many more details on this see my 2006 posts on backflow prevention, "Flappers vs. siphons" and "Follow up on flappers vs. siphons."

11) Includes Breakwater and 12) Stilling Basin at Discharge

These two options together represent a choice for prevention of waves entering the discharge tubes of the pumps.

The Corps has chosen breakwaters at the 17th Street and Orleans Avenue sites. At London Avenue, they are siting the station back from the lake at a position they claim will attenuate any waves before the pump discharges are impacted (based on a 1987 Corps study).

Waves could wreak havoc on the pumps. If the water level at the discharge (i.e. lake) side is constantly changing, the pump will have to work harder over very short periods of time. The 2009 B&V report describes the situation thusly:
"If the lake has a wave of 9 feet striking the face of the pump station, then the pumping unit will be exposed to the pulsations equivalent to the 9 feet. For a pumping unit rated at 12 feet, this is a significant increase possibly doubling the operating head acting on the pumping unit which could result in permanent damage to the pumping units or decrease the pump service life. Several pump manufacturers were contacted regarding this issue. Generally, pump manufacturers indicate that additional testing must be performed to determine the impact that waves will have on the pumping unit."

The breakwater is a manmade speedbump for waves on the lake side of the stations. it has to be big enough to knock down most of the energy of the waves so that only minimal (1-2 feet) waves reach the stations. The 2009 B&V report includes a drawing of the cross-section of the breakwater:

The other method of keeping waves away from the pumps is putting up a big wall right in front of the pump siphon discharges, creating a huge box where water would come to rest before flowing gently into the lake over the top of the wall. The wall would serve the same function as a breakwater, but it would be a lot closer to the stations. This "stilling basin" would necessarily have a higher water elevation in it since the front wall would need to be tall enough to knock down waves which were on top of a surge. There's a drawing of a stilling basin in the 2009 B&V report:

This higher discharge water level would reduce the advantage of the siphon and would make the pumps work harder, meaning larger motors, gearboxes, generators, buildings, and the like. It's not exactly the best choice, which is probably why the Corps went with the breakwaters. However, it's truly impossible to know whether it was the best way to go from an economic point of view, since the Corps has redacted all that information out of the 2009 B&V report.

One final note on this. The IER #5 has 159 instances of the word "breakwater," but none of the word "stilling." Had the 2009 B&V report been released during the IER #5 comment period in May, people may have considered whether a stilling basin was a superior alternative to the two breakwaters proposed for 17th Street and Orleans Avenue. But the public was never availed of that opportunity, since the existence of the B&V report was never confirmed until well after the end of the comment period.

13) Removal of ICS facilities

Part and parcel of this whole project is that these new stations replace the current Interim Closure Structures (ICS). Every plan calls for that, though the Corps has looked at what it would take to keep the current ICS facilities in place. It would be far cheaper to do so than to build new stations.

I'm going to hold off on talking about this particular topic because it deserves a post of its own. For the sake of this post, suffice to say that every plan calls for getting rid of the ICS facilities after the mew pumping stations are brought on line.


So that's all the various features that make up the pump stations, as listed in the 2009 B&V report. From what I've read, it would appear the Corps has cheaped out on the following features for their Option 1 stations:

1) Includes Floodwall/Levee Upgrades - no upgrades appear to be planned, even though the inclusion of gates would seem to require it on two of the three canals.

3) Channel transitions - the Corps wants to put a turbulence-inducing retaining wall, or "step," to account for the elevation difference between the current canal bottoms and the lowered sills. In the long run this will cause damage to the pumps and will be a maintenance headache with silt building up at the bottom of the step.

5) Formed Suction Intakes - the Corps knows these will be required for Option 2, just like the deepened foundation they are already including. However, they are not including them in their version of Option 1, pushing the FSI costs into an Option 2 at an indeterminate future time. This appears to be a direct instance of the lowballing of Option 1 costs and the inflation of Option 2 costs.

6) All Electric Pumps - This "feature" only truly appears in the Cost Report. There will undoubtedly be diesel pumps in the pump stations, so this is probably another effort to drive down the reported cost of Option 1 at the expense of reality.

7) Pump Station Sized for Future Pump Capacity
8) Pump Capacity Sized for Future Pump Capacity
9) Fuel Storage and Generator Sized for Future Capacity

These three features leave out the actual equipment that would accommodate future interior drainage expansion by the Sewerage & Water Board, including only space for the equipment. This is another way to minimize reported cost.

Also, the Corps is only planning on installing pumps, motors, gearboxes, switchgears, and other pump-related equipment that is sized for Option 1, rather than looking ahead and installing oversized equipment which could be recycled for Option 2. Again, this chops current costs while raising the bills in the future, making Option 1 look better at the expense of Option 2.

As you can see, the Corps has done as much as possible to drive down the reported costs for Option 1. In some cases they have eliminated features like FSIs and diesel pumps from their Option 1 cost estimate in order to squeeze that square peg into their $804 million round hole. In additon, they appear to have passed some of those costs on to Option 2, making that Option look that much less attractive. When combined with the increase of $1 billion in the Option 2 station costs in the span of 3 years, it's obvious there's little to trust in the Corps' estimates, which makes the decisions being made based on those estimates suspect as well. And of course, their entire plan leaves the same, defective floodwalls in place along the canals for New Orleans to deal with.

The best way to proceed, rather than allowing the Corps to play with the numbers and the designs, is to get an independent estimate of the permanent pumps project while all the features that are common to Options 1 and 2 proceed. Simultaneously, the Corps should shift money to the permanent pump project to accommodate all those common features.

Unfortunately the move for an independent study slowed when the Landrieu/Vitter amendment to the 2009 Energy & Water Resources appropriations bill - which authorized such a study - died in conference in September. It still needs to happen, because the Corps simply cannot be trusted with this project at this point.

Previously: Part 1 Part 2 Part 3


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