LARGE PROJECT Winner: FORT PIERCE CITY MARINA

The Fort Pierce City Marina was severely damaged when Hurricane Francis moved through the central east coast of Florida in 2004, so the project team knew that a stronger, more resilient design was required for the reconstruction.

Located in sensitive coastal habitat, the design also needed to avoid impacts to existing resources and address regulatory constraints on filling open water.

Numerical hydrodynamic and physical modeling tools were used to optimize the structural/functional performance while maximizing the environmental enhancement of the project.

Going beyond just avoiding impacts, the project creates 13 acres of nature-like breakwater islands with more than 21 acres of environmental enhancements including oyster habitat, mangrove plantings, dune grass plantings, seagrass habitat improvements, and shorebird nesting habitat. These biologic elements tie in with the rock of the rubble mound islands to create a system that will become stronger over time.

The project is also recognized for its beneficial reuse of dredged material: all of the sand for the construction of the large dune-like island was dredged from existing navigation channels (30,000 cubic yards) or reclaimed from dredged material management areas (120,000 cubic yards).

Flint’s  Julie Kucera co-taught “Designing for Coastal Protection, Beneficial use of Dredged Materials and Sediment Dewatering with Geotextile Tubes”  at the Dredging 2015 Conference in Savannah.

Event Details:
Location: Savannah, Georgia, U.S.A.
When: October 19-22, 2015 | Where: Hyatt Regency
website: http://pianc.sites.usa.gov

This award winning project use TITANTube® dewatering tubes.  It is listed as ENR Midwest Best Projects 2015:

In spring 2010, an oil pipeline burst, discharging more than 800,000 gallons of oil into Michigan’s Kalamazoo River. The remediation of the Morrow Lake and Delta areas began in 2014.

The project employed more than 30 dredges, barges and other pieces of heavy equipment—along with approximately 10,000 linear ft of dredge pipe—within a 327-acre operational area accessed through one entry/exit point. To minimize traffic, crews utilized remote-operated booster pumps, which reduced the labor requirements and associated support equipment. Post-dredging surveying confirmed that remedial action levels were achieved.

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A stacked sand-filled geotextile tube structure was specified to form the perimeter of Tern Island with the interior filled with sand. From this island, groins constructed of sand-filled geotextile tubes as a core for the structures project outward. These tubes were installed on top of stone-filled marine mattresses that served as a foundation layer, as well as offering scour protection. Over the geotextile tubes, thicker stone-filled polymeric mattresses were installed as an intermediate armor layer to minimize the overall stone thickness required. Ultimately, a final layer of large armor stone was installed over these mattresses to provide additional protection from a storm surge. The peninsula that projects from the mainland was constructed in a similar manner.

Since the tubes were filled with unwashed quarry sand, a geotextile composite fabric was initially specified to contain the sand fines and reduce potential turbidity, as well as to provide high UV resistance. The geotextile fabric was sand color to blend in with the environment should it become exposed.

In 2014, hurricanes Fran and Jeanne inflicted substantial damage to the Ft. Pierce Marina’s inner docks and caused the complete loss of its outer docks. The client desired a design to provide hazard mitigation against future storm events as well as environmentally enhancing the Indian River Lagoon.

Rather than use a composite geotextile at a significantly higher cost for constructing the geotextile tubes, an innovative woven geotextile was approved as an alternative since it met the specified turbidity criteria, had significantly higher UV resistance than that of the composite fabric, and had a high angle of friction permitting the tubes to be stacked while minimizing the possibility of slippage.

Because the tubes were an integral structural component of the island system, extensive consideration was given to the integrity of the geotextile fabric and seams. This design improved on the design of similar, but much larger, projects previously constructed in the Middle East.The innovative fabric used to construct the geotextile tubes proved to be an ideal alternative to the geotextile composite originally specified at significantly less cost to the owner. Only minimal turbidity from the tubes was observed and no tube slippage or construction damage to the tubes was encountered.Although on a smaller scale, this artificial island system is the first project in Florida to replicate the natural barrier islands along the southern Atlantic coastline of the U.S. A waterfront mosaic was created with the structures having varying heights and widths, all while protecting the marina—its primary purpose. Additionally, this innovative green project permits habitat and recreational activity to coexist in the environment. It provides hazard mitigation against future storm events, as well as enhancing the Indian River Lagoon. Mangroves and coastal dune vegetation were planted to stabilize the islands and provide additional habitat. Oyster shells and lime rock were used at lower elevations to promote the establishment of oyster beds, bottom communities and other essential fish habitats.This is an innovative project that will enhance tourism, fishing, birding, as well as promoting interest in downtown development. Because it provides excellent storm protection as well as being habitat driven, it is a win/win for all parties involved.

Deer Island is a 3.5-mile long spindle-shaped island located just off the coast of Biloxi, Mississippi. The island is owned by the State of Mississippi and is part of the Mississippi Department of Marine Resources (MDMR) Coastal Preserves Program. One of the aims of the MDMR program is to preserve and restore Mississippi’s coastal ecosystems to perpetuate their natural characteristics, features, ecological integrity, social, economic, and aesthetic values for future benefit. As one of the most important properties in the Coastal Preserves Program, the restoration of Deer Island has received considerable interest. The Deer Island Restoration Project is part of an on-going, multiple-project, joint effort by the U.S. Army Corps of Engineers (USACE) Mobile District, the MDMR, and local environmental groups to restore Deer Island to its 1850’s footprint.

Though much of Deer Island endured through catastrophic storm events over the last century including Hurricanes Camille, Ivan, and Katrina, the storms destroyed forested areas, significantly eroded the sandy shoreline, and left elevations too low to support marsh vegetation. The primary objective of the Deer Island Restoration Project was the restoration of marsh along the Mississippi coast for environmental benefit. Through creative thinking, innovative design concepts, and collaborative partnering, the USACE, MDMR, and local stakeholders, also identified several other objectives for the project.  Together, the project team and stakeholders developed a plan that would deliver economic and social benefits as well.

The Deer Island Restoration Project included the filling of the west end breach, the restoration of the southern shoreline, and strategic vegetation plantings. Approximately 1.95 cubic yards of hydraulically-dredged material from a nearby borrow site were utilized to fill the west end breach and restore the southern shoreline. Over 300,000 plants were planted on the island and, currently, another 325,000 plants are being planted. Importantly, the project included the construction of a 1 million cubic yard capacity lagoon specifically designed for the beneficial use placement of fine-grained dredged material from Federally-authorized navigation channels. 170,000 cubic yards of dredged material were placed in the lagoon in October 2011.

The principles and practices used for the Deer Island Restoration Project provide significant environmental benefits for the region, as well as protection for the City of Biloxi from storm events, recreation opportunities for people, and hard-to-come-by economically feasible
and environmentally acceptable beneficial use opportunities for dredged material. The project is a credit to the USACE Mobile District, the MDMR, and the stakeholders whose efforts yielded such diverse and important benefits.

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Ship Island is a barrier island located 12 miles off the US Gulf coast near Gulfport, Miss. It is approximately seven miles long, 1/8-mile wide and predominately barren of grass and foliage. It also offers the only deep-water harbor between Mobile Bay and the Mississippi River. During Hurricane Camille in 1969 the island was severed, effectively forming two separate islands – East Ship Island and West Ship Island. No perrmanent inhabitants reside on the islands and the only permanent structure is historic Ft. Massachusetts, built in 1861.

As part of a $300 million project to make Ship Island whole again, the U.S. Army Corps of Engineers began dredging sand from the sea floor and placing it on the north shore beach of West Ship Island in August 2011. Since the dredging activity would create significant turbidity that could damage prized sea grass beds, the Corps identified a need for a turbidity barrier with a high UV resistance and a vertical curtain having a small aperture size to sufficiently contain suspended sediment, yet allow water to pass through. A continuous and secure anchorage system to the seabed, in addition to high upper buoyancy, was necessary due to frequent tropical storms, including possible hurricanes. Accurate and sustainable placement was paramount whereby the vegetation it was intended to protect was not damaged.

The stringent Corps requirements necessitated a radical change in design from past turbidity barriers. Buoyancy tubes were previously available in only a few common diameters. Water depth, current velocity, tidal range and weather conditions necessitated infinite buoyancies to suit site-specific conditions. To solve this problem, a buoyancy tube sleeve was fabricated in the desired diameter from heavy woven geotextile fabric with an ultra-high UV resistance and then filled with spray injected foam. Once the foam expanded, it embedded into the fabric weave, creating an extremely strong buoyancy unit. A continuous and secure anchorage system was also required to prevent displacement of the barrier which could damage the sea grass. Previously used chain ballasts and cables attached to anchors in the sea floor would not provide an adequate bottom seal, thus allowing suspended sediment to escape underneath. This method of anchorage required expensive components, as well as extensive time to install. To address this concern, an anchor tube sleeve constructed also of heavy woven geotextile fabric was attached to the bottom of the filtration curtain. Once the barrier was positioned in the desired location, the tube was then filled with sand hydraulically with a small pump creating an extremely secure anchorage system. As with the upper buoyancy tube, infinite anchor tube diameters were possible to provide the necessary ballast to suit site-specific conditions.

A total of 5,500 linear feet of TITANBoom® was installed, and though it was intended to perform for only five months per the contract requirements, it functioned as specified for the 12-month project duration. During this time, the turbidity barrier withstood the impact of a Category I hurricane, as well as several tropical storms. Since there was no displacement of the barrier during the term of the contract, no damage to the sea grass beds occurred. This is also the only known instance where a turbidity barrier withstood a hurricane with no noticeable damage or displacement. Once the barrier system was removed and brought ashore upon contract completion, the empty anchor tube was removed from the barrier and disposed of. The turbidity barrier could then be shipped to the manufacturer for installation of a new anchor tube, permitting it to be reused on a future project. Product cost, as well as both installation and removal time, was significantly less than previously used turbidity barriers. Additional savings were realized since no maintenance was required during the lifespan of the turbidity barrier. Due to the superior performance of TITANBoom®, it has set a new industry standard for turbidity barriers used in severe marine environments, resulting in a new Class IV category.

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