Fix the pumps

Friday, June 24, 2011

WCC pumping shortfall alleviated slightly

[Updated July 7, 2011. See end of post]

As I reported earlier this year, the Corps and their contractor on the West Closure Complex (Gulf Intracoastal Constructors, or GIC) were unable to have all 11 of the pumps installed and running on June 1, 2011 (see the earlier post for the basics of the West Closure Complex, or WCC). We know from press coverage and the SLFPA-W reports filed by Danny Caluda that 8 of the pumps passed their wet and dry testing just before the deadline. Fortunately, it appears the clause within the specifications that would have allowed the wet tests to be waived has not been activated.

The pumps are numbered 3 through 13. Pumps 1 and 2 were eliminated from the design as a cost saving measure, and the remaining 11 pumps were redesigned to make up the flowrates of the removed pumps.

Pumps 6 through 13 were the ones declared ready on June 1, 2011 after their tests. Now pump 5 has passed its wet testing.

Mr. Caluda tells me the successful 4 hour wet test took place on June 14, 2011, meaning there are now 9 of 11 pumps available for stormwater removal on the west bank.

The modeling done by the Corps in connection with the consequences of the pumping shortfall is summarized in this table from the Interim Standing Instructions attached to the WCC Water Control Plan:

Water elevations behind the stations are shown in the left hand column. The reason they stop at 8.2 feet is that is the elevation when stormwater - pumped from local pump stations into the the detention basin formed by the Harvey and Algiers canals - would overflow the floodwalls and levees along those canals. This table assumes two things:

1) The floodgates at the WCC are closed, necessitating turning on the WCC pumps to remove the stormwater from the detention basin

2) The local pumping stations are pumping continuously the whole time, a circumstance the Corps calls "unlikely," but we all know what happens with events the Corps calls "unlikely."

Along the bottom row of the table is the total amount of time for that overflow to occur. It happens because the WCC has no spare capacity built it; it can only keep up with the local pumping stations with all 11 of its pumps on. As you can see, with only 8 pumps it would take a little over 17 hours for the local pump stations to overwhelm the WCC pumps and send water into neighborhoods (either over the floodwalls or because local pump stations would be shut down). The addition of a ninth WCC pump buys over 8 more hours.

Mr. Caluda says pump no. 4 is next up, but not for at least two more weeks.

[Update - July 7, 2011

According to Mr. Caluda, Pump 5 is due to dry tested July 7, 2011. Details on the specifics of dry and wet testing can be found here.

After that, pump 4 is anticipated to be wet tested on July 19, 2011. Testing dates for pump 3 are currently unknown.]


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