A request for specific plans to deal with high-hazard locations on or near National Forest lands along the proposed Atlantic Coast Pipeline (ACP) was submitted by the National Forest Service (NFS) on October 24. The submission to the Federal Energy Regulatory Commission (FERC) noted that the ACP “would cross some very challenging terrain in the central Appalachians” and that the route traverses “steep slopes, presence of headwater streams, geologic formations with high slippage potential, highly erodible soils, and the presence of high-value natural resources downslope of high hazard areas” that “are exacerbated by high annual rates of precipitation and the potential for extreme precipitation events.”
The NFS letter notes that “similar hazards on other smaller pipeline projects in the central Appalachians have led to slope failures, erosion and sedimentation incidents, and damage to aquatic resources” and that the agency “is concerned that crossing such challenging terrain with a much larger pipeline could present a high risk of failures that lead to resource damage.”
The ACP has previously proposed implementing “best in class” slope stabilization and erosion/sedimentation control measures, but the NFS is asking that “documentation of the effectiveness of these techniques” be provided. Six high-hazard locations in the George Washington National Forest and four in the Monongahela National Forest are identified in the filing. It is indicated that additional high-hazard areas may be addressed.
Specifically, the ACP has been asked to present designs for the selected sites that clearly illustrate the following:
- Anticipated hazards at each site;
- How the hazards will be minimized, to include specific techniques and materials tailored to the conditions of each site;
- Plan and profiles (cross section(s) perpendicular to centerline, and a longitudinal cross section along the centerline) with dimensions (feet) showing 1) the original ground surface, 2) the maximum extent of the cut, fill and spoil during construction, 3) the post-construction reclaimed ground surface, showing reclamation backfill, reclaimed slopes, and the permanent right-of-way;
- Short-term and long-term measures (i.e., construction vs. operation and maintenance periods);
- Provisions for ensuring that long-term stabilization features will remain in place and effective over the life of the project, without the need for continual maintenance;
- Rationale and supporting documentation for the likelihood that the techniques and materials used at each site will be effective; and
- Potential resource impacts in the event of a failure, and how the potential for such impacts will be minimized.