Stemming the tide

Projects harness precipitation to prevent flooding

By Angelle Bergeron

In areas below sea level, flood control is an ever-present element of public works construction.

From maintaining and upgrading existing drainage systems to creating new structures, contractors are reaping the benefits of projects designed to harness the New Orleans area's abundant precipitation.

The U.S. Army Corps of Engineers maintains the lion's share of such projects, albeit with a limited and sometimes unreliable budget. The nearly $40 million Harvey Canal Sector Gate Complex is making history as the largest current contract for the corps and the only sector-gate system in the area designed strictly for flood protection.

When complete, the gate will close only during a hurricane.

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New Orleans-based Boh Bros. Construction began work in March 2004 on what was originally a $35.7 million contract to construct a cast-in-place concrete foundation and 27-ft.-long wall system to support two 25-ft.-tall, 170-ton steel gates.

The contractor is constructing huge cofferdams in the middle of the canal. Once the water is pumped out, Boh will build the structure in dry conditions 26 ft. below the surface of the water under regular marine traffic.

Boh's contract also requires constructing floodwalls to tie into the Cousins Street Pumping Station and provide one of the final connecting links in the Corps' huge Westbank and Vicinity New Orleans Hurricane Protection Project, said Carol Burdine, senior project manager for the corps' New Orleans District.

The Harvey Canal Sector Gate Complex is the gateway between hurricane protection on the east side of the canal and the existing Algiers levee system.

Originally scheduled for completion in December 2006, the project has run into a few snags. Boh's original contract called for constructing a temporary fender system to protect the cofferdam and provide an 80-ft.-wide opening for marine traffic.

The contract also stipulated that the system would be moved twice during the project, but Boh had to re-design the fender system to be moved twice a month and create a 100-ft. opening.

This resulted in a 40-day work extension, said Vincent Saladino, Boh's project superintendent.

"Now the corps has postponed the start date for another portion of the project, a concrete closure wall that we have to build to tie into the Cousins Pumping Station," Saladino added.

The corps awarded Texas-based AquaTerra Contracting Inc. an $11 million contract for a portion of the Cousins Pump Station Complex Discharge Channel, Flood Walls and Concrete Culvert, said Stuart Waites, project manager for the corps.

"The work consists of the prefabrication and installation of a 110-ft. by 126-ft. float-in concrete culvert structure under the Lapalco Bridge in the Harvey Canal," Waites said. AquaTerra's contract also includes channel excavation, embankment work, riprap, constructing floodwalls and relocating 36-in.-diameter city water lines that were moved to accommodate the discharge culvert.

"AquaTerra fabricated the culvert north of the project at Bollinger's yard on the Canal, floated it to the Lapalco Bridge, then flooded the chambers and sunk it into place," Waites said.

The contractor experienced what Waites referred to as "normal, excusable" construction delays and is expected to complete in April instead of the original contract date of June 2004. Boh's contract, a portion of which has been hindered by AquaTerra's late completion, has been modified to accommodate the delays, he said.

Although Boh Bros.' contract is now approaching $40 million, the contractor doesn't expect to receive more than $17 million from the Corps this year, reflecting a general trend of funding woes for anyone doing business with the Corps.

Patriot Street Canal. Belle Chasse-based Circle Inc., contractor for the $12.2 million Patriot Street Canal in Barataria, delayed construction on that flood-control project several months until the corps could pay up.

Awarded in Fall 2003, Circle's contract includes constructing a concrete flume and slope paving along 3,700 lin. ft. of an existing, man-made canal.

"We were scheduled to start work in December when there were rumblings that the Corps of Engineers was running short of funds," said Matt O'Brien, project manager for Circle. The contractor spent September to December 2003 designing the temporary restraining structure and then, after a nearly $1 million outlay for sheet piles and cranes, it decided to wait on the final budgetary decisions of the Corps.

"When they officially announced in February 2004 that they weren't paying until October, we went to work and kind of paced ourselves to alleviate delaying the start of the job until October," O'Brien said.

Originally scheduled for completion in late October, the deadline has been pushed to May 2006.

Although Circle continues to forge ahead, progress isn't what the contractor anticipated.

"The TRS (temporary restraining system) is the horse that drives the carriage," O'Brien said. "We wound up using longer, heavier sheets and they are driving harder and pulling harder than the soils reports would indicate."

Circle is working in 300-ft. sections, blocking the canal with sand dams and then re-routing the flow of water. Because the canal provides drainage for the surrounding community, Circle must stop work and break their dams when there is any substantial rainfall.

"When you break the dam and let the water flow through, you have to go back and clean up, pump it out and you can lose anywhere from three to 10 days every time," O'Brien said.

So far, Circle has completed 1,200 of the total 3,700 ft. of flume and remains on schedule in spite of 19 flood modifications within a year, said John Messina, quality control. It's rather ironic that water remains the biggest obstacle to completing this particular flood-control project. "We're working in the downhill side of water and the trick is always keeping the water off of you," Messina said. "Even when it's not raining, we are always working to keep water off the site."

Working to staunch the constant flow of water with a slow, tiny trickle of funds seems to be the norm for the corps. The Patriot Street Canal project is one of approximately 40 contracts in Jefferson Parish funded through the Southeast Louisiana Flood Control program, said Stephen Hinkamp, resident engineer for the Corps' SELA Jefferson projects.

"There have been some budget problems for the past two years and we've been delinquent," Hinkamp said. The Circle contract is phone one and, although a phase two is on the books there are no immediate plans to let the job due to lack of funds, Hinkamp said.

"I can't promise anything on the budget and I can't promise a May 2006 finish date for this phase because I can't predict the rain," Hinkamp said.

Comite River Diversion Canal. Keeping high and dry during construction has been the primary concern of B&K Construction, the Mandeville-based contractor awarded the $27.7 million Corps of Engineers Comite River Diversion Canal project in September.

"We're building a control structure in a 100-ft.-deep hole," said Blake Andrews, project manager for B&K. "That's probably the biggest challenge, maintaining a dry hole."

Before B&K mobilized on the site, James Construction of Baton Rouge did some site clearing and excavation. B&K is handling the second of 15 phases on the project, which involves further excavation and construction of the Lilly Bayou control structure, Andrews said. To complete the task, B&K brought in a dewatering engineer, Marion Skouby, from Missouri.

The engineer has designed many such systems and worked with B&K on previous projects, Andrews said.

The 30-month project is the largest contract B&K has ever handled and the contractor is purchasing and installing a onsite concrete plant. B&K will also be digging a small section of earthen channel on either side of the structure and placing riprap.

The job is scheduled to be completed in February 2007 and will reduce water levels in the Comite and Amite rivers.

Useful Source:

For more information about the New Orleans District, go to: http://www.mvn.usace.army.mil/