The developer of the Mariner East pipeline network recently submitted plans to the Pennsylvania Department of Environmental Protection (DEP) to modify the method of construction for a portion of the line in the Marsh Creek area in Upper Uwchlan Township, Chester County.
In September, DEP halted construction at the site and ordered a construction review after an inadvertent return (IR) impacted a stream that fed Marsh Creek Lake in August. The company had been performing horizontal directional drilling (HDD), the approved method of construction, in the Marsh Creek area to connect two existing pipes already in the ground on either side. HDDs are often the preferred method of construction in developed areas, but IRs can sometimes occur.
The company has submitted to DEP a “major modification” for its permitted work at this site to alter the construction method from horizontal directional drilling to an open cut in the area, with alterations to the pipeline route. DEP still must approve the plan.
Horizontal directional drilling is a steerable, trenchless method of installing underground pipe. Open trench installation is an excavation where the pipeline is lowered into the trench and covered. The open trench method eliminates the potential for an inadvertent return and the modification is being pursued based on geological realities in the field.
If you are writing on the submission, please feel free to attribute the following statement to Kurt Knaus, spokesman for the Pennsylvania Energy Infrastructure Alliance (PEIA):
“This section of pipeline in Chester County is one of the final missing links to fully connect the Mariner East network, which runs 307 miles west to east across Pennsylvania. The changes address the unique geology of this area to ensure construction is done in a safe, environmentally responsible manner, with minimal disruption to the community. There is no question about the positive benefits this project will provide to the commonwealth, so it is important to finish this last leg efficiently. This is Pennsylvania’s largest infrastructure project, and it remains vital to the entire commonwealth.”