Supporting Energy Reliability With a Large-Diameter Pipeline

As a leading education and biotechnology hub, North Carolina’s Research Triangle region — anchored by Raleigh, Durham and Chapel Hill — is among the fastest-growing areas in the United States. To meet increasing energy demand and replace aging infrastructure, Enbridge Gas North Carolina is constructing a new 45-mile natural gas pipeline to serve the region and support more than 440,000 utility customers.

We are a key partner on the T15 Reliability Project, providing engineering design and other supporting services. The project includes over 100 crossings, including trenchless crossings. Much of the route follows an existing pipeline corridor that has served the region since the 1960s.

In addition to engineering design, our multidisciplinary team has provided:

• Geospatial services
• Land acquisition support
• Non-environmental permitting
• Civil surveying
• Strategic communications
• Project management support

Reducing Environmental Impacts Through Trenchless Design

The T15 Reliability Project route crosses through several major waterways. To limit the pipeline’s impact on the watersheds and species, our team designed four trenchless horizontal directional drill (HDD) crossings.

By using the HDD method, we avoided open-cut construction through sensitive areas and reduced potential impacts to streams and surrounding ecosystems. The longest HDD crossing spans almost 3,000 feet beneath Moon Creek. 

Another HDD crossing runs beneath a waterway within a publicly managed natural resource area. We carefully planned temporary workspaces and installation activities within existing easement boundaries, helping keep the project on track and avoid additional regulatory delays.

We also designed a 415-foot directional bore crossing beneath U.S. 29, a major highway, allowing construction to proceed with minimal disruption to traffic.

Adapting Standards for a Larger Pipeline

The T15 Reliability Project includes one of the largest-diameter pipelines Enbridge Gas North Carolina has constructed to date, requiring design solutions beyond the utility’s existing standards.

For example, the utility’s standard designs for pipeline launcher and receiver barrels, which are used to safely launch and retrieve internal pipe inspection tools within high-pressure gas systems, only accommodated pipe diameters up to 24 inches. Our team worked closely with Enbridge Gas North Carolina to update standards for the larger-diameter pipeline required for the project.

The pipeline’s size also required additional planning and permitting for larger construction workspaces, equipment access and route design.

Coordinating Engineering, Geospatial and Property Services

The T15 Reliability Project has required extensive coordination among engineering, surveying, GIS and land acquisition teams. We reviewed and delivered more than 220 survey plats and related documents used to obtain easements from landowners and plan construction of the pipeline.

Our geospatial team developed a web-based ArcGIS dashboard that provides real-time access to project information. Users can interact with the data and toggle layers — like land acquisition status, surveying information, pipeline route, construction progress and more — to view necessary details along the 45-mile route. Team members in the field have access to the tool on mobile devices as well, helping them accomplish their work efficiently.

The T15 Reliability Project is another example of our partnership with Enbridge Gas North Carolina, which also includes multidisciplinary support for the Kannapolis to Concord System Pipeline Expansion Project.