Thursday, September 8, 2011

New Tools See Use in Fighting Midwest Floods

Photo Courtesy of Portadam LAST LINE OF DEFENSE Flood control products such as Portadam were deployed on short notice at the Fitzgerald Casino in Tunica, Miss., to provide protection from the rising waters of the Mississippi River.

As cities and municipalities in the Midwest deal with seasonal floods, a new crop of flood barrier products have emerged in recent years.

When Mark Bittner, city engineer for Fargo, N.D., planned for this year's floods, he had a budget in hand. While many towns and cities must wait for federal and state aid, Fargo has a dedicated half-cent sales tax for flood control.

When the Red River began to rise this spring, Bittner had more than sandbags. "We had used some Hesco [Concertainer] bastions in 2009 and 2010, but we had some real seepage problems on soft ground," Bittner says. "This year we used a mix: some Hesco, some AquaFence and TrapBags. The rapid deployment stuff is very attractive to us."

Contractors and municipalities fighting seasonal floods are almost spoiled for choice when it comes to flood barrier products available today. Hesco's Concertainer gabions and DefenCell's geotextile fabric forms were originally developed by the British-based defense contractors for military use. These quickly erected containers for sand and fill were designed to stop bullets and shrapnel, but they have found a new market in flood protection.

Sentinel Barriers, Ft. Myers, Fla., built upon the traditional sandbag concept with TrapBags, five-sided polypropylene bags up to 6 ft in height that require heavy equipment to fill. Former heavy-highway and underground contractor Everret "Buzz" Ward invented the TrapBag while serving as disaster recovery contractor for Ft. Myers. "I developed the TrapBag while trying out different containment vessels. I settled on an unequal pentagon with the bulk of the weight at the bottom."

Flood barriers from Norway-based AquaFence and Williamstown, N.J.-based Portadam consist of lightweight metal frames with waterproof panels or sheeting. The speed with which this type of barrier can be erected is a major draw.

"We are primarily a rental business," says Bob Gatta, CEO of Portadam. "Ninety percent of our business is cofferdam or retention related, but we get calls from contractors who are handling flood control and they know our brand."

One such call came into Portadam in early May. A subcontractor working on flood protection at the Fitzgerald Casino in Tunica, Miss., along the Mississippi River, needed to erect a flood barrier. Within three days 2,100 ft of Portadam was delivered, and a 20-worker team installed it within a day.

While most buyers want to see flood barriers in action before buying, there is one trusted option for testing in a controlled setting. The U.S. Army Corps of Engineers' Engineering Research and Development Center in Vicksburg, Miss., runs trials on various flood control barriers in a specially designed basin equipped with three powerful wave machines. Initially used to test a handful of products in 2004 at the request of Congress, the ERDC facility has offered vendors the chance to have their products put to the test for a fee of about $60,000.

No regulations

"There are no regulations requiring testing of [flood barriers], but the whole purpose is for manufacturers to sell their product, and people ask if it has been tested at the ERDC," says Don Ward, research hydraulic engineer with the Corps of Engineers. "Some products are about to go to market and the vendors want testing done, other times they have revised their design and want more testing." The Corps does not endorse or recommend any products, and test results are the property of the vendor.

Not all vendors seek out the ERDC tests. "Our product has been used by the Corps for nearly seven years. They did a demo project outside of Baton Rouge and liked the results," says Sentinel Barrier's Ward. "Some people, not the Corps, mind you, say the best testing is in the field."