Press Releases

SWBNO Releases After-Action Report on Response to June 10 Rain Event

For Immediate Release: Wednesday, June 17 2020

NEW ORLEANS – The Sewerage and Water Board of New Orleans (SWBNO) released its after-action report on its response to the rain event of June 10, fulfilling the utility’s promise to the City Council and the public. The report details the timeline of the rain; SWBNO’s operational response; what likely caused Turbine 4 (T4) to shut down; the impact of that power loss on the drainage system; and adjustments the utility will make for future rain events. 

The report, created through a review of the utility’s logbooks and a thorough after-action briefing among the operations team members, found no evidence that operator error caused or contributed to the challenges the drainage system experienced during the rain that day.

“No one predicted that more than 3 inches of rain would fall in little more than an hour that morning,” said SWBNO Executive Director Ghassan Korban. “But our team responded well. They did – and continue to do – a tremendous job operating a drainage system that still runs practically the same way it did a hundred years ago.”

Due to the age of major pieces of equipment, including the pumps and turbines, and the sheer complexity of the drainage and power systems overall, unforeseen difficulties are likely to occur during any rain event. June 10 was no different.

A more detailed timeline and description of the utility’s response can be found in the attached after-action report. T4 and all 99 drainage pumps remain operational.

In summary, about 3 inches of rain had fallen at Drainage Pump Station 2 on Broad Street in Mid-City between 6:40 and 7:45 a.m. The National Weather Service issued a flash flood warning at 7:51 a.m., but by then the flooding had already begun.

As the rain began, SWBNO had T4 and its Entergy frequency changers in service. By 7:10 a.m., T4 was producing more than 10 megawatts (MW) of power. The operations team started Turbine 1 (T1) and began to move pumps from T4 to T1 when a safety mechanism tripped and T4 shut down. That safety feature protected the turbine from damage. At no time did the operators overload T4 beyond SWBNO’s internal limit for that machine of 18 MW.

The rain event timeline, supported by photos from the Real-Time Crime Center cameras, shows the floodwaters had reached their top height before T4 tripped offline. The power loss delayed SWBNO’s ability to drain the city, but it did not exacerbate the flooding that had already occurred.

With intense rain events occurring more frequently, SWBNO is taking steps to improve their storm response. For example, the team will be more aggressive in its preparations for rain. This includes going on higher alert for storms predicted to be less severe. Power equipment, such as the Electro-Motive Diesel (EMD) generators, may be started sooner than normal in anticipation of sudden intense downpours within these rain events.

The drainage system is operating this hurricane season without the comfort of 20 MW of additional power that was lost when Turbine 5 (T5) suffered an explosion in December. That loss of redundancy motivated SWBNO to improve the resiliency of its remaining power equipment. You can read about these projects at www.swbno.org.  

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Read More in the Attached Document

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