New Orleans Canal Pump Stations

25659.00 1 7 t h s t r e e t a n d lo n d o n av e n u e c a n a l p u m p s tat i o n s New Orleans, Louisiana Engineering Sustainable Practice

Parting the Waters

A short 50-foot walk from the front steps of Pontchartrain Baptist Church provides a panoramic view of Lake Pontchartrain. The sanctuary building is all that remains for nearly a block in every direction since Hurricane Katrina. Houses on all sides were either destroyed or have been demolished, and the vacant lots surrounding the church have left it isolated like an island. But two years after suffering through the devastating floods, services have now resumed. While life will never be the same for the congregation, doubts have been calmed at the completion of the 17th Street and London Avenue Canal Pump Stations.

In the aftermath of Hurricane Katrina, as part of its plan to prevent future levee failures, the U.S. Army Corps of Engineers authorized the design and construction of a series of isolating gate structures, more than 15 feet in height, across the northern end of two particularly vulnerable canals.

A team was assembled to design, test and construct the gates as well as pumping stations housing 33 huge direct-drive pumps. Total capacity of all pumps running together is 5.4 billion gallons per day over the gates into Lake Pontchartrain.

The US Army Corps of Engineers’ (USACE) project was managed by Weston Solutions, Inc., of West Chester, Pennsylvania, and the Engineering Research and Development Center (ERDC) in Vicksburg, Mississippi. The GS&P team, lead by Mike Barry, P.E., consisted of a group of engineers who would design two of the pumping stations and produce plans and specifications for civil-site, civil-process and structural aspects of the project.

Their responsibilities included work at the 17th Street Canal and London Avenue Canal Even larger than the tasks of the project were the doubts of the public. Project Manager Mike Barry explained that at the start of the project, the team made a commitment to the people of New Orleans, the entire U.S. Senate, the House of Representatives and to each other that the pumps

would be up and running before the height of the 2009 hurricane season. The pressure was enormous. Crews of 50-100 worked 24-hours a day seven days a week for six months straight, getting only one day off during the entire time—Father’s Day. But Barry said, “Everyone understood that this was the project of a lifetime.”

Lake Pontchartrain is not actually a lake at all. It opens into the Gulf of Mexico and is therefore subject to the same tides as the Gulf. Thus, the lake is also affected by storm surges. Surges of five feet or higher cause the lake to back feed into the canals and force the gates to be closed.

After the gates are shut, the canal pumps must be started to remove the initial storm surge and the storm water being pumped into the canals by the City of New Orleans.

During Hurricane Katrina, the storm surges were between 12 and 15 feet high. With the canals already overflowing, water poured over the dry side of the levees. The storm surge, as well as the movement of the water, degraded the materials in the levees, leading to several collapses. New Orleans filled up with an endless, unstoppable flow of water coming directly from the sea, causing the unbelievable devastation that the outside world watched on TV screens in August 2005. It was believed that the 15-foot-high gates mandated by the

USACE, which would be closed during a storm surge, would provide the best benefit/cost ratio for future hurricane events.

Early in the design phase there were concerns, which modeling later confirmed, that the original concept would not allow the huge volume of water to enter the pump intakes without cavitation and vortexing. This refers to the possible rapid formation and collapse of vapor pockets as well as violent whirlpools during intake that would compromise pump efficiency and possibly cause serious structural damage to the equipment. ERDC’s modeling efforts defined the necessary intake modifications, and the GS&P engineers immediately incorporated them into the final designs.

Construction proceeded on schedule. Later, fullscale testing proved that vortexing and cavitation would not be issues.

How much water?

“In addition,” noted Mark Markham, P.E., GS&P’s team project professional, “our hydraulic modeling efforts and pump discharge header design helped optimize pump performance and exceed the pumping rate objective by over 15%. This enhanced the ability of the stations to meet near-term and future City of New Orleans’ and USACE’s storm water control objectives.”

Matthew Beatty, Vice President, Mid-Atlantic Division of Weston Solutions, said, about GS&P’s work, “It is truly remarkable how you were able to completely shift gears on day one with the modeling redesign and still keep the critical path for materials procurement and construction moving forward. To not have one claim from our…subcontractors for delays is a miracle.”

On May 13, 2008, the Corps of Engineers put the gates to the test during a simulated hurricane named “Zeus.” As the residents of New Orleans looked on, the symbol of teamwork and unshakable commitment performed flawlessly. A New Orleans resident, who was in the city during Hurricane Katrina, said of the team, “They worked unbelievably hard. We know there will be other hurricanes, but we feel safer thanks to those people.”

On September 1, 2008 the pumps were tested again

by Hurricane Gustav. Although the brunt of the storm was felt in areas west of New Orleans, the gate structures and pumps at 17th Street and London Avenue canals performed as expected. Col. Al Lee, USACE District Engineer in New Orleans, was responsible for operating the gates and pumps, and reported that the emergency structures functioned at a high level. “All the pumps worked, all the gates locked in place, all of it worked,” Lee said.

For Barry and his team, there was never any doubt. ■

Together, the pumps can push through enough water to fill the Tennessee Titans Stadium or 56 billion cans of Coca Cola in a day. That is equal to a quarter of the flow of the Cumberland River and the total flow of the Delaware River. It could also provide water for 53 midsized American cities a day.

17th Street Canal Pump Station Before the job was finished over 12 thousand tons of materials and equipment would be required to complete the two pump stations. In order to operate the 33 individual pumps a minimum of 41,000 horse power is required. That’s enough to support the energy requirements of over 19,000 households all the while lowering the water level in the canal, when floodgates are closed, by about one foot every 12 minutes.

Pontchartrain Baptist Church The condos directly in front of the church have been purchased by the USACE as they still lie in the flood plain and will be razed.

London Avenue Canal Pump Station University of New Orleans campus (top right corner of picture) and adjacent neighborhoods (top left) experienced extensive flood damage.

Above With such a tight deadline many of the project’s welded components were fabricated elsewhere while the site was prepared. The 17th Street Canal pump platform was built in a shipyard in New Iberia, Louisiana, cut up into moveable pieces, carefully numbered, loaded on barges to travel back up the intercoastal waterway to be reassembled and welded secure on site. To mitigate the intense vibrations from the pump engines, the 240 foot long x 42 foot wide x 3 foot deep frame was filled with reinforced concrete.

Should the earth explode tomorrow, this platform will still be intact orbiting the sun. Left The first pump, delivered and installed on schedule, weighed 95,000 pounds, or roughly 47.5 tons.

Where are we?

Lake Pontchartrain New Orleans, Louisiana Most of the city lies at or below sea level. Although protected by levees, a simple summer shower can trigger almost instant flooding. Streets, curbs and gutters fill with water, and the permanently saturated earth struggles to absorb.

The city’s only solution to rid itself of all this water is a series of canals, which channel it northward by gravity into Lake Pontchartrain.

Gulf of Mexico

London Avenue Canal Pump Station is made up of two elevated concrete platforms which house four 350 cfs pumps per platform. Water is pumped out of four 84-inch steel discharge pipes into the lake.

17th Street Canal Pump Station is made up of eleven 350 cfs pumps on a new elevated steel platform and a gate structure housing fourteen 114 cfs pumps. Three new 108 inch discharge pipes and one modified existing 108� discharge pipe discharge the water into the lake.

Gresham, Smith and Partners provides design and consulting solutions for the built environment that contribute to the success of national and international clients. For more than 40 years, GS&P has focused on enhancing quality of life and sustainability within communities. GS&P consists of industry-leading professionals practicing architecture and engineering design as well as scientists and highly specialized planning and strategic consultants in Environmental Compliance, Aviation, Corporate and Urban Design, Healthcare, Industrial, Land Planning, Transportation and Water Services. GS&P consistently ranks among the top architecture and engineering firms in the United States. For more information regarding GS&P, visit www.gspnet.com.

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