Mitigation measures to avoid or reduce ecological impacts from an energy transmission project.
The following are examples of mitigation measures that could be applied to reduce ecological impacts of a project depending on site- and project-specific conditions. Impacts to ecological resources are related to the project footprint (e.g., land disturbance; habitat destruction, modification, and fragmentation; erosion; and hydrological alterations), project emissions (e.g., fugitive dust and other contaminant releases to air), resource use (e.g., water extraction), and the physical presence of the project facilities (e.g., collision risk for birds). Many impacts can be reduced or avoided when considered the siting and design a project during the site evaluation phase.
Develop a final set of mitigation measures for any project in consultation with the appropriate federal resource management agencies and stakeholders. Conduct these consultations in the project development process and preferably prior to final project siting and design.
Siting and Design Mitigation Measures
Siting and design considerations that mitigate impacts include:
Use existing facilities and disturbed areas (e.g., access roads, graded areas) to the extent feasible to minimize the amount of disturbance.
Configure new access roads to avoid high-quality habitats and minimize habitat fragmentation.
Locate and arrange construction staging areas in a manner to preserve trees and other woody vegetation to the maximum extent practicable.
Locate site access roads to minimize stream crossings.
Identify important, sensitive, or unique habitat and biota in the project area, and design the project to avoid (if possible), minimize, or mitigate potential impacts to these resources. The design and siting of the project should follow appropriate existing guidance, as available and applicable.
Identify wetland crossings prior to construction to minimize the span over or trenching within them and to avoid the more environmentally sensitive or wetter portions of the wetlands.
Contact appropriate federal agencies and interested stakeholders early in the planning process to identify potentially sensitive ecological resources that may be present in the area of the energy transmission project.
Review existing information on species and habitats in the project area.
Locate support towers, pipeline trenches, access roads, and facilities in areas least likely to impact important, sensitive, or unique habitats (such as wetlands).
Locate individual project facilities to maintain existing stands of quality habitat and continuity between stands.
Design stream crossings to provide in-stream conditions that allow for and maintain uninterrupted movement and safe passage of fish.
Avoid locations that are heavily used by migratory birds and bats.
Design permanent facility structures to discourage their use by birds for perching or nesting.
To reduce the operational and avian risks that result from avian interactions with electric utility facilities, design and construct transmission lines in conformance with the Avian Protection Plan Guidelines (published by the Avian Power Line Interaction Committee [APLIC] and U.S. Fish and Wildlife Service [USFWS] in 2005) and the Suggested Practices for Avian Protection on Power Lines: The State of the Art in 2006 (published by APLIC in 2006).
Avoid locating transmission lines in areas with a high incidence of fog and mist.
General Mitigation Measures
General mitigation practices and principles that could apply to any or all phases of an energy transmission project include:
Instruct all survey and monitoring personnel on the protection of ecological resources, laws pertaining to the collection and removal of these resources, and the purpose and necessity of protecting them.
Develop a habitat restoration management plan that identifies vegetation, soil stabilization, and erosion reduction measures, and requires that reclamation activities be implemented as soon as possible following facility construction activities.
Develop a plan for control of noxious weeds and invasive plants that could occur as a result of new surface disturbance activities at the site. The plan should address monitoring, weed identification, the manner in which weeds spread, and methods for treating infestations. Require the use of certified weed-free mulching.
Instruct all employees to avoid harassment and disturbance of wildlife, especially during reproductive (e.g., courtship, nesting) seasons. In addition, do not permit pets at the project site.
Conduct in-stream activities during low-flow periods and avoid activities when the area is being used by important aquatic species (e.g., salmonid spawning or migration).
When feasible, reduce the extent of habitat disturbance by keeping vehicles on access roads and minimizing foot and vehicle traffic through undisturbed areas.
Maintain noise-reduction devices (e.g., mufflers) in good working order on vehicles and equipment.
Apply erosion controls that comply with federal standards. Apply practices such as jute netting, silt fences, and check dams near disturbed areas.
Use certified weed-free mulching.
Reclaim all areas of disturbed soil using weed-free native grasses, forbs, and shrubs. Undertake reclamation activities as early as possible on disturbed areas.
Refuel in a designated fueling area that includes a temporary berm to limit the spread of any spill.
Use drip pans during refueling to contain accidental releases and under fuel pump and valve mechanisms of any bulk fueling vehicles parked at the construction site.
Address spills immediately per the appropriate spill management plan, and initiate soil cleanup and soil removal if needed.
If trucks and equipment are arriving from locations with known invasive vegetation problems, establish a controlled inspection and cleaning area to visually inspect the vehicles and equipment arriving at the project area, and remove and collect seeds that may be adhering to tires and other equipment surfaces.
Access roads should be monitored regularly for invasive species establishment, and weed control measures should be initiated immediately upon evidence of invasive species introduction.
Do not use fill materials that originate from areas with known invasive vegetation problems.
Use certified weed-free mulch when stabilizing areas of disturbed soil.
Limit herbicide use to nonpersistent, immobile herbicides and apply in accordance with label and application permit directions and stipulations for terrestrial and aquatic applications. Select herbicides for use that have low human toxicity, are effective against target species, and have minimal effects on non-target species and the environment.
Report observations of potential wildlife problems, including wildlife mortality, to the appropriate wildlife agency.
Project Phase-Specific Mitigation Measures
Mitigation measures specific to a particular phase of an energy transmission project include:
Conduct surveys for federal-protected species and other species of concern within the project area.
Evaluate avian and big game use (including the locations of active raptor nest sites, waterfowl staging areas, crucial winter and summer use areas, and migration corridors) of the project area by using scientifically rigorous survey methods.
In consultation with state wildlife agencies, establish spatial and temporal restrictions on activities that could disturb raptors during their breeding season.
Retain all ground-level vegetation and stumps left after cutting, unless there removal is necessary to install support structures, the pipeline, or other ancillary facilities.
Initiate habitat restoration activities as soon as possible after construction activities are completed within a given area.
Schedule construction activities to avoid important periods of wildlife courtship, breeding, nesting, lambing, or calving.
Establish buffer zones around raptor nests, bat roosts, and other biota and habitats of concern such as rare plants.
Use explosives only within times and at distances from sensitive wildlife or surface waters specified by federal agencies.
Use dust abatement techniques on unpaved, unvegetated surfaces to minimize airborne dust.
Cover construction materials and stockpiled soil if they are a source of fugitive dust.
If construction in wetlands cannot be avoided, activities should be done when the soils are dry or frozen and/or wide-tracked or balloon-tired equipment, timber corduroy or timber mat work areas, or some combination should be used.
Where support structures or pipelines would be placed in wetlands, excavate and stockpile topsoil separately from subsoil. Replace soils into the excavated area in the reverse of the order in which they were removed.
Biologists should accompany construction crews to ensure sensitive resources are identified and avoided.
Isolate the in-stream work area(s) and capture and release fish from the work area(s) under the supervision of a competent fisheries biologist qualified to capture fish.
In the event that a federally listed species is found during construction, work in the area will be stopped and the USFWS would be immediately notified.
Operation and Maintenance
Mark shield wires with highly visible devices such as colored spheres or flappers at key water crossings or other areas where a transmission line crosses high-value habitat for birds (particularly waterfowl and raptors).
Monitor the right-of-way (ROW), access roads, and ancillary facilities regularly for invasive nonnative plant species establishment, and initiate weed control measures immediately upon evidence of invasive species introduction or spread.
Remove all aboveground structures from the project area.
Reestablish grade and drainage pattern to the extent practicable.
Salvage topsoil from all decommissioning activities and reapply during final reclamation.
Restore the vegetation cover, composition, and diversity to values commensurate with the ecological setting.
Repeat mitigation measures used to minimize impacts to ecological resources during construction during the decommissioning/site reclamation phase.
Monitor all disturbed areas for restoration and revegetation success.