Posted on July 19, 2022
By Judith Powers
Massive project was completed on time and on budget
Courtesy USACE Charleston District
This summer the U.S. Army Corps of Engineers, Charleston District (Corps) and its local sponsor the South Carolina Ports Authority (SCPA) have nearly completed Post-45 — the deepening of the harbor’s 38.4 miles (61.7 kms) of federal shipping channel — to up to 52 feet (15.8m) to allow transit of the largest post-Panamax ships without tidal or traffic restrictions.
The name Post-45 refers to the federally-authorized depth of 45 feet (13.7m) in 2010, when the study to determine a new depth beyond 45 feet began.
Post-45 is the first federal project to be accomplished start-to-finish under the Corps’ modernized planning framework known as SMART planning, introduced in 2011. This paradigm shift is also known as 3x3x3 because it was mandated by the Corps to deliver expedited project planning decisions for no more than $3 million, within 3 years, and with 3 concurrent levels of review. The SMART planning protocol applies the questions, is it Specific, is it Measurable, is it Assignable, is it Realistic, and is it Time-Related to each individual goal in the project.
Feasibility Study: May 2011 to June 2015
“We had started the (Post 45) feasibility process prior to this paradigm shift happening,” project manager Brian Williams, who headed the feasibility study, told DredgeWire. “We had gotten down the road a few feet and were using the existing measuring stick, which could take 10 years and cost $20 million. When the 3x3x3 mandate came out, Charleston was the first to go from start to finish in this new process. We were collectively inventing the roadmap on how to get it done,” he said.
Williams has since been appointed as the deputy to the Charleston District’s senior civilian.
In May 2011, the USACE Work Plan allocated $150,000 for the feasibility study.
The first challenge was to reduce the $20 million cost of the feasibility report with an eight-to-10-year timeline to $11.7 million with a four-year timeline, in cooperation with state and federal partner agencies, Williams explained.
“We were down from $20 million but not within the mandated $3 million,” he said.
He asked for and received an exception to the 3x3x3 policy, and the planning proceeded with the $11.7 million budget and four year timeline.
“Our previous paradigm was risk averse, but as Congress pushed for faster decisions we had to go faster and assume more risk. This doesn’t mean we end up with risky products, but we decide what level of investigation is appropriate,” he said.
For example, when talking about a dredging project the primary question is ‘is it constructable and how do we go about it?’ “
Williams described some of the processes the team engaged in under the new paradigm.
“We have been operating in Charleston Harbor for more than 140 years and have amassed data on what we’re dredging. Where we were confident that the (bottom material) testing data was current, we didn’t repeat in those areas. Where we didn’t have sufficient coverage, we did a broad assessment to add to the plan,” he said.
Another example is analysis of cost of dredging to different depths. He described starting at the existing authorized depth of 45 feet and analyzing the full cost for deepening in two-foot (.6m) increments from 46 feet to 52 feet, including the amount of material to be dredged and the economic benefit of each increment. Prior to this, the Corps would have typically analyzed the costs and benefits in one-foot increments, so utilizing two-foot increments effectively cut some of the work required in half. The type of material and placement of the material were the main cost drivers.
“We had a team of 40 to 50 individuals, experts in geotechnical engineering, hydraulics, coastal biologists, economics, real estate professionals – every discipline needed to analyze the alternatives and the best interest of the federal government,” he said.
Williams explained that the Corps identified a plan (National Economic Development Plan or NED Plan) that would deepen the majority of the navigation channel to 50 feet (15.4m), but the South Carolina Ports Authority (SCPA) elected to pursue a Locally Preferred Plan (LPP) that would deepen the majority of the navigation channel to 52 feet. The LPP is the one that was recommended to and authorized by Congress with the understanding that the SCPA would pay 100 percent of the cost difference between the two plans. The Post 45 feasibility study and Chief’s Report estimated the cost difference to be approximately $44.7 million, though the actual cost difference will not be known until a fiscal closeout of the project is performed.
The planners enlisted Charleston Harbor Pilots, local tug captains and docking pilots, all of whom navigate the channels daily in all weather, for their suggestions on how much to widen channels in certain areas and dimensions needed in the turning basins. Their suggestions of the likely maximum necessary widenings and turning basin configurations were added to the feasibility plan and the costly and time-consuming ship simulations at the Engineer Research Development Center (ERDC) in Vicksburg, Mississippi were deferred until the design phase. Defining the likely maximum extent of these channel modifications helped the study team quickly quantify the likely maximum impacts from the project and sped up the coordination with state and federal resource agencies.
In October 2014, the Draft Integrated Feasibility Report and Environmental Impact Statement was released to the public, recommending deepening the federal channel portion of Charleston Harbor to 52 feet. The public review period and public meeting garnered over 600 comments, all of which were included and addressed in the final report. The report recommended the deepening of all channels, accomplished in five contracts, and including designation and improvement of all placement sites, environmental remediation, and other beneficial uses, as well as costs and funding sources.
The 386-page report included a survey of existing and future conditions; an evaluation of related problems and opportunities; development of potential alternatives; a comparison of costs, benefits, adverse impacts, and feasibility of those alternatives; and identification of a National Economic Development (NED) Plan and Recommended Plan (RP). The RP was the Locally Preferred Plan which the Chief of Engineers office agreed to in its review of the feasibility study. .
On June 25th, 2015, the Final Integrated Feasibility Report and Environmental Impact Statement was approved unanimously by the U.S. Army Corps of Engineers’ Civil Works Review Board in Washington, D.C., and a final report was released to state and local resource agencies for a 30-day review period. Chief of Engineers Lt. Gen. Thomas Bostick signed the Chief’s Report in September 2015, and the report was transmitted to Congress to be considered for authorization and funding appropriation, which would open the way to the preconstruction engineering and design phase (PED).
PED: July 2015 – December 2016
Work completed during the PED phase included the ship simulations that had been deferred from the feasibility phase, beneficial use analysis, finalizing cost estimates, and development of plans and specifications for the dredging contracts. Initial federal funding for the PED Phase was received in late July 2015, so work began immediately, though the Design Agreement that laid out the PED funding plan between the Corps and the South Carolina Ports Authority (SCPA) wasn’t signed until December, which officially moved the project into the PED phase.
In January 2016, Jo-Ellen Darcy, Assistant Secretary of the Army for Civil Works, signed the Record of Decision (ROD) for Post-45, which is the official notification to Congress that all requirements for the project had been met and it was now awaiting authorization.
The PED phase of Post 45 took 15 months and cost approximately $4.7 million.
During this stage, the harbor pilots and boat captains were taken to the Engineering Research and Development Center in Vicksburg where a sophisticated ship simulator and been programmed with the Charleston shipping channels in their proposed parameters. In one-week stints, the pilots and operators tested ship movements. Comprising three bridge simulations and 11 plasma screen displays, the simulator calculated ship response to all conditions that a ship could encounter, including changed topography, channel depth and width effects, and ship motion. The operators were presented with unexpected scenarios to navigate, testing the adequacy of the channel design. The simulations informed the planners which areas of the channel should be widened, and which areas did not need to be widened as much as was planned in the feasibility study, producing cost savings and decreased construction time.
The project impacted the equivalency of approximately 324 acres (131 hectares) of wetland habitat through a shift from fresh/brackish wetland vegetation to brackish/salt wetland vegetation. These losses were mitigated by preserving about 665 acres (269 hectares) of wetlands near the Francis Marion National Forest. These preserved lands will provide important physical, chemical, and biological functions for the Cooper River Basin and contribute to the sustainability of the watershed by ensuring that the bottomland hardwood wetlands and emergent wetlands are sustained in perpetuity.
Construction Phase: December 2017 to September 2022
On December 16, 2016, President Barack Obama signed the Water Infrastructure Improvements for the Nation (WIIN) Act of 2016 which included authorization for the Post-45 Project. The WIIN Act included Titles I through IV of the 2016 Water Resources and Development Act (WRDA), which listed all the dredging projects requesting authorization.
That day, Charleston District Engineer Lt. Col. Matthew Luzzatto announced that the WIIN Act had authorized the Post-45 project, and that the District could proceed with the final phase – the construction phase. He stated that the entrance channel design phase was 95 percent complete, and that the plan was to have a dredge in the water by December 2017.
The first two contracts, to deepen and extend the entrance channel, were awarded to GLDD in late 2017.
Contract 1, valued at $47.6 million, employed primarily hopper dredges to create the 3.5-mile (5.6 km) extension to the entrance channel. The material was all new work dredging and was placed in the Ocean Dredged Material Disposal Site (ODMDS).
Contract 2, awarded to GLDD for $272 million, was awarded in October 2017 and began in May 2018 and was completed in December 2021. It involved removal of roughly 13 million cubic yards (9.9 million cubic meters) of sand, rock and clay that was also placed in the ODMDS or in the artificial reefs for mitigation or in a U-shaped berm/reef along the south, west and east perimeters of the ODMDS, rising about 10 feet (3m) above the natural bottom elevation. The berm defined the newly-expanded boundary/capacity of the ODMDS to 427 acres (172 hectares). The berm serves as additional marine habitat as well as for containment of dredged sediment.
To use the rock in a beneficial way, the design called for building underwater artificial reefs, six as a least-cost disposal method and two as mitigation for loss of hard bottom habitat. The equivalency of 30 acres (12 hectares) of hard bottom were impacted by the dredging. As mitigation, two reefs totaling 66 acres were built nearby to provide habitat for a range of marine life, such as sponges and soft corals, starfish, crabs, and fish such as black sea bass.
According to Lynn Nietfeld, Southern vice president (SVP) of GLDD, “This was a very complicated and challenging project on a lot of levels. It is exactly the type of project we excel with. Our project management and crews performed our three contracts (GLDD also won Contract 4 in the main harbor) in a record setting safety and operational effort. The challenging weather and environmental constraints of the project required innovative equipment, practice, and serious attention to details.”
Among some of the equipment GLDD used on the Charleston contracts were cutter suction dredges Texas and Carolina, hopper dredges Ellis Island and Terrapin Island, and clamshell dredges GL 54 and GL 58. The Texas, paired with Spider Barge 175 loading scows, completed 20 percent of all the work performed in Charleston. In total, over 5,000 scow loads and nearly 2,000 hopper loads of material were removed from the shipping channel during the three contracts. Strong partnerships within the local maritime industry also aided in the overall success, said Nietfeld.
Contract 3 deepened the lower harbor channel to 52 feet from the inland end of the entrance channel, approximately half-way along the length of the jetties, to the Wando Welch terminal on the Wando River. Widening the Wando turning basin from 1,400 feet (426.7m) to 1,650 feet (503m) allowed two 14,000 TEU and above ships to pass each other and turn around without restrictions. The $112.9 million contract was awarded to Norfolk Dredging Company in August 2019. It involved dredging 11 million cubic yards (8.4 million cubic meters) of material from 2.4 miles of channel, with placement in the ODMDS.
“Our clamshell dredges Virginian and Atlantic began working in Charleston in October 2019. The Virginian was on the project the entire time, and the Atlantic was replaced with our new dredge Baltimore in July 2021. This was the first use of the Baltimore, so we obviously had to work through some bugs that come launching a new dredge,” Mike Haverty, executive vice president of Norfolk Dredging Company told DredgeWire.
The Virginian used a Cable Arm clamshell for soft material and a conventional hard bottom bucket for hard material. The Atlantic used both a Cable Arm and a hard bottom bucket, and the Baltimore used two sizes of hard-bottom conventional buckets.
The deepening was completed in April 2022, five months ahead of schedule, and the company spent several months at Wando Terminal completing final contract requirements and performing repairs, pulling out in early July.
Crab Bank Wildlife Refuge
A popular beneficial use site of dredged material from the deepening is not owned by the Port or the Corps, but by the South Carolina Department of Natural Resources (SCDNR). Crab Bank is an island and bird sanctuary that has existed in the harbor since the 1950s when it was created from dredged material about 1000 yards (914m) off the Shem Creek pier.
The island regularly contained dozens of sea bird species and was known to have as many as 5,000 nests on it in the summer. Over the years it was eroded by hurricanes and storms until in 2017 Hurricane Irma eliminated the last of the high ground
A nearby section of the deepening project in Contract 3 contained sand suitable for restoration of the island, but because the restoration was not the least-cost placement method, a non-federal sponsor was required to absorb the additional cost of using the sand for this purpose. The SCDNR, in cooperation with the Coastal Conservation League and a range of community entities and private individuals committed to raising the needed $132,000. They exceeded the dollar mark, providing the means to help other projects.
Norfolk brought in dredge Charleston specifically to perform the Crab Bank project.
“This was an option with the original bid that USACE exercised,” Haverty explained.
From September 14th to November 4, 2021, Norfolk’s 24-inch cutterhead dredge Charleston moved 660,000 cubic yards (504,606 cubic meters) of sand from the channel to create the 32-acre (12 hectare) crescent-shaped island. The Corps had specified that the surface be irregular and that the contractor not grade and level the sand. This presented terrain more conducive to birds nesting than a flat surface.
On April 5, 2022, representatives from the Corps Charleston District and SCDNR, South Carolina Gov. Henry McMaster and other elected officials, and community members, gathered at Alhambra Hall, a re-purposed ferry building in Mount Pleasant, to celebrate the completion of the island. On that day, the first American oyster catcher nest had been observed on the island by SCDNR scientists. In succeeding months bird life has abounded on the island. It is the “lasting legacy” of Post 45 and was a win-win for the community and the sea birds.
Contract 4 deepened the channel in the Cooper River from the Lower Harbor to the new Hugh Leatherman Terminal to 52 feet. It was awarded to GLDD in September 2020 and dredging began that October. The $40.8 million contract involved removing four million cubic yards (3 million cubic meters) of material from 9.7 miles (15.6 km) of channel using a pipeline and clamshell dredge and placing it in upland sites. Building out the turning basin was an important part of this expansion. Work was completed in January 2022.
The final contract, number 5, went to Marinex, a local Charleston dredging company, for $32 million to deepen the Upper Harbor above the Hugh Leatherman Terminal to the new North Charleston Terminal to 48 feet (14.6m) a distance of .7 mile (1.1 km). The depth in this reach is 48 feet because ship size is constrained by the Don Holt bridge, which has a vertical clearance of 155 feet (47m) – not enough for the new, larger ships. The contract was awarded in December 2020 and will be completed in fall 2022. Their mechanical dredge Wadmalaw has been primarily used, but dredging is paused while the Clouter Creek upland placement site dewaters from the previous project.
There are four upland placement sites on Daniel Island and Clouter Creek Island within short pumping distances of the dredging. Yellowhouse Creek placement area along the Cooper River has also been used for the project. Approximately 7.7 million cubic yards (5.8 million m3) of dredged material were placed in upland sites.
Bethney Ward, Post-45 project manager, said “The COE has post construction work of five years of environmental monitoring, to gauge the effects of the artificial reefs near the entrance channel, water quality in the harbor, including salinity and how it affects marshes along rivers, and the potential for shoreline erosion from the post-Panamax ships traversing the deepened channels.
She continued, “We are thrilled that the deepening is going to be finished on time and on budget.”
Brian Williams pointed out that the two $600 million infrastructure projects built recently are both in Charleston – the Arthur Ravenel, Jr. Bridge over the Cooper River, completed in July 2005, and the Post-45 deepening project. Since the Corps massive infrastructure project is underwater and the bridge can be seen for miles around, they are not often thought of as two similar large construction projects, but each project is vitally important to the growth and prosperity of South Carolina, he said.
“The district is proud of the fact that Post 45 was the first large navigation study completed under the SMART planning process and became a model for other Corps studies around the nation,” said Williams.