To help locate and resolve post-Katrina hazards lurking beneath the murky waters of the Port of New Orleans’ Inner Harbor Navigation Canal, Boh Bros. Construction Co., L.L.C. of New Orleans tapped into some innovative underwater imaging technology and expertise offered by engineering and surveying firm C.H. Fenstermaker & Associates Inc.
Using specially configured scanning sonar and software, Fenstermaker’s Acoustic Imaging Group is gathering visuals of the underwater portions of support structures for vehicular and railway bridges that cross the canal at Almonaster Ave., Florida Ave. and Seabrook and analyzing them for damage. The group is also scanning the canal for sunken barges, ships, boats and other debris that could impede harbor traffic. The results are then shared with Boh Bros., Modjeski and Masters Consulting Engineers and the U.S. Army Corps of Engineers so problems can be addressed.
Fenstermaker, a 55-year-old surveying, engineering and environmental consulting firm based in Lafayette with offices in New Orleans, Baton Rouge and Houston, provides acoustic imaging and measurement services using specially configured scanning sonar systems. The firm employs the only mechanically steered-beam, digital, high-resolution scanning sonar units of this type in existence. The equipment, configured under the direction of Fenstermaker’s Underwater Acoustics Group, is designed to maximize performance and resolution in shallow brown water or turbid environments such as those found in New Orleans’ post-Katrina waterways. The sonar equipment can be mounted on a vessel or submerged into the water on a tripod to conduct its scans.
Boh Bros. Construction Co., L.L.C., an established construction firm specializing in industrial and commercial projects, marine construction, dock work and bridges, is under contract with the U.S. Army Corps of Engineers to remove obstructions and debris from the bottom of the canal. Boh Bros. chose Fenstermaker to assist because of its unique expertise in high-resolution underwater acoustic imaging.
So far, Fenstermaker, whose work began Sept. 17, has conducted acoustic profiling, acoustic imaging and acoustic stationary imaging on the Florida Ave. bridge and the Inner Harbor Navigational Canal where findings to-date include a sunken barge and a sunken 60’ sailboat. Fenstermaker also helped define the gap between a sunken dry dock and the pilings at the Florida Ave. bridge, information that enabled officials to open the way for limited traffic through the canal. A bathymetry survey was also performed to determine the depth of the water at the Almonaster Ave. bridge. Acoustic profiling was used to map scour holes and the surrounding water bottom in two of the three bridge areas and will be performed in the third area later. Fenstermaker expects to complete its portion of the project before the month ends. The final task will be a post-recovery scan of the canal.
With combined experience of more than 25 years in underwater imaging and measurement systems, the Acoustic Imaging Group of C. H. Fenstermaker & Associates Inc. provides acoustic applications, analysis and interpretation. With their unique technology, C. H. Fenstermaker & Associates is able to provide high-definition water bottom imaging, water bottom hazard detection and mapping, compressed “Z-swath” bathymetry, water bottom imaging and profiling under floating obstacles such as vessels and barges, and underwater structure deformity inspection, such as bridge pier and dam inspections for deformities that may have structural consequences. The group provides visualization and measurement of underwater structures and features at ports and harbors, bridges, as well as at dams, water control structures and navigable waterways. Fenstermaker also works with the oil and gas industry and has lent its technology and expertise to forensic investigations as well as many other applications.
Ken LaBry, manager of the firm’s Acoustic Imaging Group, says, “High-definition underwater acoustic visualization is changing the way we see the world. We have assembled a team of qualified personnel and given them the best tools possible for performing this work. The imaging services we currently use provide our clients with unparalleled precision in underwater applications.”
Kam Movassaghi, Ph.D., P.E., president Fenstermaker, adds, “Our Acoustic Imaging Group utilizes the most advanced technologies in imaging data collection and visualization. The devastating hurricanes of the past several weeks have tested the resources of the state of Louisiana and its people. We are pleased that we are able to use this advanced technology to assist government agencies and businesses in this tremendous recovery effort.”
About C.H. Fenstermaker
C.H. Fenstermaker is a multidisciplinary consulting firm founded in 1950. The company’s expertise includes civil engineering, surveying and environmental consulting. Fenstermaker’s offices are located in Lafayette, New Orleans, and Baton Rouge, Louisiana and Houston, Texas.