Before any construction can begin, a survey crew carefully surveys and stakes the construction right-of-way to ensure that only the pre-approved construction work space is cleared.
A large project typically is broken into manageable lengths called “spreads,” and utilizes highly specialized and qualified work-groups. Each spread is composed of various crews, each with its own responsibilities.
A crew is responsible for removing trees, boulders and debris from the construction right-of-way and preparing a level working surface for the heavy construction equipment that follows.
A crew installs silt fence along the edges of streams and wetlands to prevent erosion of disturbed soil. Trees inside the right-of-way are cut down, and the contractor removes or stacks the timber along the side of the right-of-way depending on the landowner’s wishes.
The trenching crew typically uses a wheel trencher or backhoe to dig the pipe trench. The Pipeline and Hazardous Materials Safety Administration, or PHMSA, requires the top of a pipeline to be buried a certain distance, depending on its size and the soil type, below ground. The pipeline must be buried deeper at river and road crossings.
If the crew finds large quantities of solid rock during the trenching operation, it uses special equipment or explosives to remove the rock. The crew uses explosives carefully, in accordance with state and federal guidelines, to ensure a safe and controlled blast.
In cultivated areas, the topsoil over the trench is removed first and kept separate from the excavated subsoil, a process called topsoiling. As backfilling operations begin, the soil is returned to the trench in reverse order with the subsoil put back first, followed by the topsoil. This process ensures the land is returned to as close as possible to its original condition.