Energy Transmission Operations Impacts
Potential environmental impacts from the operation and maintenance phase would would be associated with long-term habitat change within the right-of-way (ROW), maintenance activities, noise, the presence of workers, and potential spills.
Typical activities during the operation and maintenance phase include: operation of compressor stations or pump stations, ROW inspections, ROW vegetation clearing, and maintenance and replacement of facility components.
Environmental impacts that could occur during the operation and maintenance phase would mostly occur from long-term habitat change within the ROW, maintenance activities (e.g., ROW vegetation clearing and facility component maintenance or replacement), noise (e.g., compressor station, corona discharge), the presence of workers, and potential spills (e.g., oil spills).
The following potential impacts may result from the operation and maintenance of an energy transmission project.
Sources of noise during the operation and maintenance phase would include compressor or pump stations, transformer and switchgear at substations, corona discharge from transmission lines, vehicles and machinery, and aircraft overflights for inspection. The primary impacts from noise would be localized disturbance to wildlife and recreationists.
Vehicular traffic and machinery would continue to produce small amounts of fugitive dust and exhaust emissions during the operation and maintenance phase. These emissions would not likely cause an exceedance of air quality standards nor have any impact on climate change. Trace amounts of ozone would be produced by corona effects from transmission lines (e.g., less than 1.0 part per billion which is considerably less than air quality standards). Routine venting of pipelines and breakout tanks (for liquid petroleum products and crude oil) would also cause localized air quality impacts.
Impacts during the operations and maintenance phase could include damage to cultural resources during vegetation management and other maintenance activities, unauthorized collection of artifacts, and visual impacts. This threat is present once the access roads are constructed and the ROW is established, making remote areas more accessible to the public. Visual impacts resulting from the presence of the aboveground portion of a pipeline, transmission lines, and associated facilities could impact cultural resources that have an associated landscape component that contributes to their significance, such as a sacred landscape or historic trail.
During operations and maintenance, adverse impacts to ecological resources could occur from:
Ecological resources may continue to be affected by the reduction in habitat quality associated with habitat fragmentation due to the presence of the ROW, support facilities, and access roads. In addition, the presence of an energy transmission project and its associated access roads may increase human use of surrounding areas, which in turn could impact ecological resources in the surrounding areas through:
The presence of an energy transmission project (and its ancillary facilities) could also interfere with migratory and other behaviors of some wildlife.
Possible environmental justice impacts during operation include the alteration of scenic quality in areas of traditional or cultural significance to minority or low-income populations. Habitat modification, noise impacts, and health and safety impacts are also possible sources of environmental justice impacts.
Hazardous Materials and Waste Management
Industrial wastes are generated during routine operations (e.g., lubricating oils, hydraulic fluids, coolants, solvents, and cleaning agents). These wastes are typically placed in containers, characterized and labeled, possibly stored briefly, and transported by a licensed hauler to an appropriate permitted off-site disposal facility as a standard practice. Other wastes include the sludge removed from pipeline pigging operations. Impacts could result if wastes were not properly handled and were released to the environment. Environmental contamination could occur from accidental spills of herbicides or, more significantly, oil from a pipeline accident.
Human Health and Safety
Possible impacts to health and safety during operations include exposures to electromagnetic fields (EMF), accidental injury or death to workers during operation and maintenance activities, and accidental injury or death to the public (e.g., from off-highway vehicle (OHV) collisions with project components or from airplane collisions with transmission lines). In addition, health and safety issues include working at heights, working around energized equipment, working in potential weather extremes, and possible contact with natural hazards, such as uneven terrain and dangerous plants, animals, or insects. There is an increased potential for fires from electrical discharges from energized equipment.
Land use impacts would be minimal, as many activities could continue within the ROW (e.g., agriculture and grazing). Other industrial and energy projects would likely be excluded within the ROW. In addition, construction of facilities (e.g., houses and other structures) would be precluded within the ROW and roads would only be allowed to cross ROWs, not run along their length). Recreation activities (e.g., OHV use and hunting) are also possible, although restrictions may exist for the use of guns, especially for aboveground pipelines or transmission lines. The ROW and access roads may make some areas more accessible for recreational activities. Activities centered on solitude and scenic beauty would potentially be affected. Military operations and aviation could be affected by the presence of transmission lines. For example, transmission lines could affect military training and testing operations that may occur at low altitudes (e.g., military training routes).
Impacts during the operations phase would be limited to unauthorized collection of fossils. This threat is present once the access roads are constructed and the ROW established, making remote areas more accessible to the public.
Direct impacts would include the creation of new jobs for operation and maintenance workers and the associated income and taxes paid. Indirect impacts are those impacts that would occur as a result of the new economic development and would include things such as new jobs at businesses that support the expanded workforce or that provide project materials, and associated income and taxes. The number of project personnel required during the operation and maintenance phase would be about an order of magnitude less than during construction. Therefore, socioeconomic impacts related directly to jobs would be minimal. Potential impacts on the value of residential properties located adjacent to an energy transmission project would continue during this phase.
Soils and Geologic Resources (including Seismicity and Geo Hazards)
Following construction, disturbed portions of the site would be revegetated and the soil and geologic conditions would stabilize. Impacts during the operation phase would be limited largely to soil erosion impacts caused by vehicular traffic and machinery operation during maintenance activities. Any excavations required for pipeline maintenance would cause impacts similar to those from construction, but to a lesser spatial and temporal extent. Herbicide would likely be used for ROW maintenance. The accidental spills of herbicides or pipeline product would likely cause soil contamination. Except in the case of a large oil spill, soil contamination would be localized and limited in extent and magnitude.
No noticeable impacts to transportation are likely during the operation and maintenance phase. Low volumes of heavy- and medium-duty pickup trucks, personal vehicles, and other machinery are expected to be used during this phase. Infrequent, but routine, shipments of component replacements during maintenance procedures are likely over the period of operation.
The aboveground portions of energy transmission projects would be highly visible in rural or natural landscapes, many of which have few other comparable structures. The artificial appearance of a transmission line or pipeline may have visually incongruous “industrial” associations for some, particularly in a predominantly natural landscape. Visual evidence of these projects cannot be completely avoided, reduced, or concealed. Additional visual impacts would occur during maintenance from vehicular traffic, aircraft, and workers. Maintenance, replacement, or upgrades of project components would repeat the initial visual impacts of the construction phase, although at a more localized scale.
Impacts to water resources during the operation and maintenance phase would be limited to possible minor degradation of water quality resulting from vehicular traffic and machinery operation during maintenance (e.g., erosion and sedimentation) or herbicide contamination during vegetation management (e.g., from accidental spills). However, a large oil pipeline spill could potentially cause extensive degradation of surface waters or shallow groundwater.