In designing and constructing a critical section of subsea pipeline, the project team at the James River Crossing pushed the perceived limits of horizontal directional drilling with large-diameter high-density polyethylene (HDPE) tubing. The HDD pullout of 5,700 feet under the Newport News Shipping Channel, which the team claims is a record distance, set a new benchmark for 42-inch HDPE pipe and demonstrated that thermoplastic strength could be installed at a distance primarily associated with welded steel.
The James River Crossing Pipeline creates a link between the Boat Harbor Pumping Station and an onshore pipeline system that carries raw wastewater to the Nansemond and SWIFT treatment plant. [Sustainable Water Initiative for Tomorrow] installation At the plant, wastewater is treated and purified, and delivered to recharge wells that help support the long-term restoration of critical regional aquifers.
Garney and Dewberry brought together geotechnical, marine and trenchless expertise before issuing the RFP, giving the team time to evaluate alternatives and reduce risk before the design moved forward.
Photo courtesy of Garney
Delivered under a design-build contract awarded to Garney and Dewberry in April 2022, JRX includes more than 4.5 miles of HDPE power under the James River, including a critical passage below the Newport News Shipping Channel. A busy sea corridor that supports both commercial shipping and naval operations, the channel had to remain open with uninterrupted ship traffic while minimizing disturbance to the water and protecting the surrounding marine environment.
Because the pipe would carry wastewater and was placed in a brackish water environment, the Hampton Roads Sanitation District specified that high-density polyethylene pipe be used, says Paul Longo, associate vice president and regional market sector leader in the water market sector for designer Dewberry. The main concern was that the district wanted a pipeline that would last at least 75 years. Although Dewberry investigated using coated steel, the risk that the pipe could corrode and fail was still considered too high. “They wanted to never have to come back [to fix] that and the risk of a coating system failing is greater than the fact that HDPE is a full wall of corrosion-resistant thermoplastics,” says Longo.
Team members and local fire department personnel gathered for a safety briefing and mock man-overboard training in the JRX barges.
Photo courtesy of Garney
Contracted under a design-build delivery method, the district outlined some general specifications but left the details up to the design-build team. “Basically, they gave us a flow rate and said it had to be trenchless with a hard drive,” says Jeff Seal, vice president of Garney. “They gave us two connection points, one on either side, and for the rest, they said, ‘Figure it out.’
Initially, the district envisioned a 3,200-foot crossing with two offshore platforms at each end during installation. One of the proposed rigs would have been in a location that could have a major impact on a nearby fuel oil tank and two docked navy ships. “It would have totally congested the area and made it difficult, if not impossible, for everyone,” Seal says.
In response, the team favored extending the horizontal directional drilling distance to eliminate the need for a second offshore rig. The strategy would reduce the risk of work on the water, simplify sequencing, avoid disruption of the heavily used marine terminal and save more than $10 million in the budget.
The strategy would also significantly increase risk during pipeline installation. According to Garney, the longest known HDD installation of 42-inch HDPE with the specified wall thickness was about 4,000 linear feet. By removing the rig, the JRX team extended the drill to 5,700 feet.
Compared to steel, HDPE is more flexible and cannot withstand the same tensile loads. The team solved the pulling force problem with a combination of engineering and custom equipment. A custom pipe pusher, capable of applying up to 750,000 pounds of force, was mounted on the offshore work platform to complement the drill’s pulling capacity. This reduced the net tensile stress on the pipe and kept the loads within safe limits throughout the 24-hour drilling operation. The team also worked with the HDPE manufacturer to tighten the ovality tolerance from the standard 5% to 3%, which improves both installation performance and long-term pipe integrity.
The hydraulic design added another layer of innovation. Instead of using one pipe diameter for the full route, the team used three sizes. The mile-long section below the shipping channel required 42-inch HDPE DR-11, a smaller, thicker-walled pipe designed to withstand the demands of the installation. For the remaining segments, the team increased the pipe to 48 and 54 inches. Larger diameters reduce pumping head and power consumption, helping to optimize life cycle costs of the HRSD.
The 24/7 removal work required continuous coordination between the team as the 42-inch HDPE pipe was advanced down the hole.
Photo courtesy of Garney
Before committing to the final drill alignment, the team conducted additional geotechnical soundings and a full pilot drill. This fieldwork validated subsurface conditions, confirmed that the alignment would hold, and gave the team real data to work with instead of assumptions. Field verification also reduced subsurface uncertainty before the team committed to removal. The withdrawal itself was a one-shot, 24-hour operation with no margin for a restart. Drilling crews, offshore support and pipe handling crews had to keep up at all times.
To support a withdrawal of a length not previously achieved for this pipe size and wall thickness, the construction team consulted HDD experts from around the world. The German-engineered custom pipe pusher mounted on the work platform helped balance the forces during installation, while the tighter ovality specification on the HDPE pipe helped ensure it performed as designed through the full length.
Additional cost savings were achieved when the team realigned parts of the work to avoid privately leased oyster beds. This saved approximately $2 million while reducing the environmental impact. In the shallow water areas, the team revised the means and methods and used thicker-walled pipes, eliminating the need to lay mats of hinged concrete blocks over the pipe. This approach saved an additional $1.8 million while simplifying installation and reducing material handling in the river.
Not only was the four-year project completed on time in January 2026, but the construction cost also came in at $139 million, a savings of $14 million over the original proposal price.
