“The highest risk and resource-intensive Mission Essential Task (MET) we collectively train on is port opening and harbor clearance,” 511th Engineer Dive Detachment Commander Cpt. Olivia Schretzman said. “If we do not provide accurate infrastructure assessments, open ports, repair bridge sections, or clear obstacles in inland waterways, we negatively impact all sustainment and maneuver operations. It is a no-fail mission.”
Schretzman commands the 511th Engineer Dive Detachment, a 25-Soldier team that deploys worldwide, performing complex and dangerous engineer tasks at depths of up to 190 feet.
“These tasks include surface supplied or "hard hat" diving, SCUBA, hydrographic surveys, underwater inspections, swift water diving, demolition, construction, and hyperbaric chamber operations,” Schretzman said. “One of the most vital missions for an Engineer Diver, or 12D, is port opening and harbor clearance operations, including underwater welding, hydraulic tools, underwater cutting, lift bag operations, and clearing obstacles and debris.”
Schretzman explained that simulating a damaged bridge is a difficult task, so when the Memphis District reached out for assistance, both parties would benefit from the job.
“The Ensley Engineer Yard had a partially sunken bridge that needed repairs, and we needed high-intensity port opening training,” Schretzman said. “This operation became known as Operation Mississippi Freedom.”
Schretzman said they wanted to name the operation “Mississippi Freedom” because, “we wanted to showcase how fixing a bridge section enables the movement of over 175 million tons of cargo along the Mississippi River. The Memphis District is directly responsible for servicing 355 miles of the Mississippi River watershed, and failure to maintain these operations could cost the nation over a billion dollars in fuel and shipping costs.”
This water-buoyant bridge is only one of two available access points to the Ensley Engineer Yard structure referred to as the ‘stringout’.
“The stringout is approximately 5,445 feet of floating wharf running generally in an east/west orientation,” Ensley Engineer Yard Marine Facilities and Equipment Specialist Chad Chrisco said. “The stringout serves as a docking facility to support maritime mission operations including dredging and revetment vessels, barge mounted cranes, tugboats, and crew boats. It also supports vessel repair dry dock facilities.”
Repairing any section of this multifunctioning pier requires specialized skills and concentrated preparation; this is where the 511th Engineer Dive Detachment and Ensley Engineer Yard skilled tradesmen come in.
“On March 7, the 511th EDD executed a leader’s reconnaissance to establish communication with USACE Memphis Project Managers, collect intelligence, and build a bill of materials list prior to execution,” Schretzman said.
According to Schretzman, a major outcome of the reconnaissance identified the need to use a double-sided patch technique, a technique that provides an additional layer of protection.
“Due to the low tide in the summer months, the bridge section sits on the bottom of the riverbed, creating friction points and massive cracks,” she said. “The 60-year-old six compartment bridge section had a rusted-out hull and ten ruptures ranging from one-inch holes to ten-foot large cracks.”
With reconnaissance complete and a plan of attack in place, a team of 23 Soldiers from the 511th, 74th, and 569th EDDs, along with two-thirds of the detachment’s equipment, deployed to Ensley Engineer Yard.
“The Ensley Engineer (Yard) facility had a perfect amount of construction material and a local scrap yard for the operation,” Schretzman said. “Additionally, a machinist shop onsite provided labor, tools, and supplies to complete the bridge repair.”
Schretzman added that having all these resources available while deployed is highly beneficial as it provides the opportunity for Soldiers to think outside the box, which is something they would certainly need to do when confronting challenges during this type of operation.
To begin repairing, and ultimately salvaging this weighty bridge, the team had to complete what would be the most pivotal of phases: reducing the water inflow to each compartment of the bridge to allow for internal and external patching.
“The divers emplaced waterproof fabric (industrial tarps) along the hull, which reduced water flow by nearly 95 percent,” 511th EDD Executive Officer 1st Lt. Adriel Moran said. “Waterproofing allowed divers to enter each compartment to identify holes and other significant damage.”
The divers were then broken down into four dive teams before entering the dewatered compartments, where they worked together to build patch designs for each of their sections.
“The largest and most complex patch installed in the hull utilized salvage matting and over 100 pounds of concrete to reduce water flow,” Schretzman said. “Effective internal patch installation reduced flooding of the bridge in all compartments by 95 percent and raised the bridge out of the water by over 3 feet.”
The raising of the bridge immediately resulted in reduced utility costs, removing electrical safety concerns, and increasing the bridge’s load capacity. If, however, the bridge went unrepaired, it would have continued to sink, needing around the clock electrical pumps to keep it afloat.
“Last year there was a major power outage, which led to the pumps shutting down,” Schretzman explained. “This led the bridge to sink and not allow personnel and equipment to get to the dredges on the Mississippi. We knew that we had to make sure that the inside of the bridge section was secure, as well as ensure that the outside was protected from debris.”
While the repairs resulted in immediate relief, repairing this bridge serves to do more than providing access to the Ensley Engineer Yards motor vessels.
“The hard work and ingenuity of the 511th EDD resulted in the bridge successfully operating without the use of the dewatering electrical pumps for the first time in over 25 years, saving the U.S. Government over five million dollars in a replacement bridge,” Schretzman said.
Not only did Operation Mississippi Freedom prove the diverse capabilities of the 20th Engineer Brigade, but Schretzman also pointed out the highlighted importance of working as a team.
“Chad Chrisco, General Facilities and Equipment Specialist, and Marine Facility and Equipment Specialist Lemont King were vital in our teams’ success,” Schretzman said. “Together, we worked through a deliberate plan to repair the barge using innovative patching techniques. The Metal Shop and the scrap yard proved to be one of the most important aspects of our mission as well, and the Ensley Metal Shop provided incredible support to the operation overall.”
At the end of the operation, the 511th EDD removed 198,200 gallons of water from the bridge. The average sized swimming pool holds about 18,000 to 20,000 gallons of water, so this dive team removed almost 10 swimming pools’ worth of water from the bridge in just under a month, as they were here from Mar. 20 to April 16.
The team also conducted 23 dives, with over 1,400 minutes of time underwater, and installed 23 patches, all varying in size and material.
The divers and our Ensley Engineer Yard team also did everything safely, completing this entire task without one incident.
Schretzman said they executed lockout/tagout practices for the electrical pumps, wore proper Personal Protective Equipment (PPE) throughout the entire exercise, and trained on confined space rescue techniques.
“We ended the mission with zero mechanical and diving injuries, highlighting our dedication to safety,” Schretzman added. “Mr. Kevin Piggot, the District Dive Safety Coordinator for the District, was instrumental in making sure we followed all OSHA and EM 385-1 processes and procedures.”
Operation Mississippi Freedom showcased how teamwork, innovation, and resourcefulness can solve some of the most complex problems there are, and for the 20th Engineer Brigade, that happens to be port opening and harbor clearance. The Memphis District Team is grateful for the reparation of this vital engineer yard bridge, as well as successfully working with the Army Dive Team.