USA: Joint Venture Results In Deeper River Channel and Added Storm Protection

While driving alongside Beach Boulevard in Pascagoula, MS, the average person would never know that just six months earlier the majority of that beach didn’t exist. It’s hard to imagine a beach was just created out of nowhere, but that’s exactly what the U.S. Army Corps of Engineers, Mike Hooks, Inc., and Gulf Sand & Gravel, Inc. D.B.A. ENCO Dredging did during their collaboration on the Pascagoula Beach Boulevard project as part of the Mississippi Coastal Improvements Program (MsCIP).

The Pascagoula River, also referred to as Mississippi’s “Singing River”, flows generally southward through the heart of the state’s swamps before reaching the Gulf of Mexico in a rich network of channels and bayous. The river serves as a host to a great deal of industry in the surrounding area, including Northrop Grumman Ship Systems, a shipbuilder and the state’s largest employer; Signal International, an oil platform builder, Mississippi Phosphates, a larger producer of diammonium phosphate, and one of the largest Chevron refineries in the country. As with most rivers in the south, the Pascagoula River becomes shallow when sediment from upstream settles to the river’s bottom and poses a problem for passing ships and boats. Neglecting the shallow channels is clearly not an option as it would disrupt so much local commerce. Regular maintenance dredging is required to maintain navigable waterways and eliminate disruptions to maritime traffic.

In 2005, Hurricane Katrina devastated the city of Pascagoula, much like the rest of the Gulf Coast. Her 20-foot storm surge flooded nearly 92% of Pascagoula, resulting in most of the homes along Beach Boulevard to be destroyed in their entirety. The storm surge also caused significant damage to Beach Boulevard and threatened the integrity of the seawall. Foundation material landward of the seawall began to migrate seaward through cracks in the seawall. Additional seaward foundation material at the toe of the seawall was eroded by wave action. The project, as designed by the Corps, provided a beach to buffer peak wave action, thereby maintaining seawall functionality and integrity.

The need to dredge the river to keep its channels navigable was inevitable, but the idea of using the dredged material elsewhere is a phenomenal approach to solving two problems at once. Typically in navigation dredging, the material is removed and disposed of. However, the Army Corps saw the opportunity to use the dredged material removed from the river to create a beach along the sea wall to protect it from future storm surges. The only problem was the area that needed to be dredged is located over 7 miles away from where the beach would be created.

The Army Corps hired Mike Hooks, Inc., a construction contractor headquartered in Westlake, LA, as the prime contractor for the project. Mike Hooks, Inc. employed ENCO Dredging, a dredge contractor based in Gulf Shores, AL, as subcontractor after reviewing their plan to pump the material downriver and create a beach that would tie into an existing beach. It’s not necessarily easy to move such a large quantity of sand that far, but this team of experts proved that it is indeed possible!

ENCO has much experience in beach restoration, especially along the Gulf Coast. The company proposed dredging the material from upriver, pumping the material 40,000 feet (7.6 miles) down river where the silt would be separated from the sand, and depositing the sand near the sea wall, creating a strip of beach that would eventually tie into an existing beach.

With such a long distance between the dredging and deposit sites, ENCO had to use an extensive fleet of dredging equipment. The fleet included (3) dredges and (4) booster pumps, all manufactured by M&S Equipment, a DSC Dredge LLC Company. An 18” x 16” cutter head dredge was used to remove the material. The dredge’s robust design permits the user to easily maneuver the dredge, allowing for maximum coverage. The other two dredges served as booster pumps along with (3) additional floating boosters and (1) land-based booster pump. The boosters were strategically placed about every mile or so and were required to transfer the material a total distance of 7.5 miles.

According to Rex Watson (left) and Mike Smith (right) of ENCO, they pumped 300,000 cubic yards of sand. ENCO also pumped material for geotubes, which are strung together like sausage links, totaling 7,700 feet in length. The geotubes were placed approximately 100 feet seaward of the seawall in the beach template in an effort to help control erosion of the newly developed beach.

The beach was never intended for recreation, but instead serves as protection to the sea wall and Beach Boulevard.

When walking along the beach, the furthest thought from many minds is where the sand between their toes came from, but every beach has a story. Locals and visitors of Pascagoula will now be able to enjoy a beach that didn’t exist last summer, while residents of the area have the peace of mind that their homes are more protected than ever.

[mappress]

Source: DSCDREDGE, May 13, 2010

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