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Ecological Mitigation Measures

Mitigation measures to avoid or reduce ecological impacts from solar energy development.

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, erosion, changes in runoff patterns, and hydrological alterations), project emissions (e.g., fugitive dust, sediment runoff, air releases, water releases), and resource use (e.g., water extraction). Many impacts can be reduced or avoided when considered during the siting and design 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 early 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:

  • Review existing information on species and habitats in the project area. Contact appropriate agencies early in the planning process to identify potentially sensitive ecological resources that may be present in the project area.
  • Conduct pre-disturbance surveys and site facilities away from important ecological resources (e.g., wetlands, water bodies, important upland habitats, sensitive species populations).
  • Ensure protection of important resources by establishing protective buffers to exclude unintentional disturbance.
  • Use existing facilities and disturbed areas (e.g., access roads, graded areas) to the extent possible to minimize the amount of new disturbance. New access roads and rights-of-way (ROWs) should be configured to avoid high-quality habitats and minimize habitat fragmentation.
  • Develop a site and ROW reclamation plan that addresses both interim and final reclamation requirements and that identifies vegetation, soil stabilization, and erosion reduction measures.
  • 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. Prohibit the use of fill materials from areas with known invasive vegetation problems.
  • Develop a spill management plan.
  • Minimize the amount of land disturbance and develop and implement stringent erosion and dust control practices.
  • Minimize the number of stream crossings when locating access roads. When stream crossings cannot be avoided, use fill ramps rather than stream bank cutting.Design stream crossings to provide instream conditions that allow for and maintain movement and safe passage of fish.
  • Develop site fencing in conjunction with appropriate natural resource agencies (e.g., to either allow or prevent site access by wildlife species such as the kit fox or desert tortoise).

General Mitigation Measures

General mitigation practices and principles that could apply to any or all phases of a solar energy project include:

  • Educate workers regarding the occurrence of important resources in the area and the importance of their protection, including the appropriate regulatory requirements.
  • Schedule activities to avoid disturbance of resources during critical periods of the day (e.g., night) or year (e.g., periods of courtship, breeding, nesting, lambing, or calving).
  • Instruct employees, contractors, and site visitors to avoid harassment and disturbance of wildlife, especially during reproductive (e.g., courtship and nesting) seasons. In addition, do not allow pets at the project site.
  • Establish buffer zones around raptor nests, bat roosts, and other biota and habitats of concern such as rare plants, if site studies show that proposed facilities would pose a significant risk to these species.
  • Reduce habitat disturbance by keeping vehicles on established access roads and by minimizing foot traffic in undisturbed areas.
  • Avoid the spread of invasive nonnative plants by keeping vehicles and equipment clean. Reseed disturbed areas with native plants during interim and final reclamation.
  • Regularly monitor the solar field, access roads, and ancillary facilities for invasive nonnative plant species establishment. Initiate control measures immediately upon evidence of invasive species introduction or spread.
  • Limit herbicide/pesticide use to nonpersistent, immobile herbicides/pesticides and apply only in accordance with label and application permit directions and stipulations for terrestrial and aquatic applications.
  • Apply erosion controls that comply with local, state, or federal standards. Apply practices such as jute netting, silt fences, and check dams near disturbed areas.
  • Use dust abatement techniques on unpaved, unvegetated surfaces to minimize airborne dust.
  • Apply spill prevention practices and response actions in refueling and vehicle-use areas to minimize accidental contamination of habitats.
  • Address spills immediately per the appropriate spill management plan, and initiate soil cleanup and soil removal if needed.
  • Turn off all unnecessary lighting at night to avoid attracting migratory birds.

Project Phase-Specific Mitigation Measures

Mitigation measures specific to a particular phase of a solar energy project include:


  • Conduct blasting for raw materials only within specified times and at specified distances from sensitive wildlife or surface waters as specified by state, tribal, or federal agencies.
  • Maintain noise-reduction devices (e.g., mufflers) in good working order on vehicles and construction equipment.
  • 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.
  • If trucks and construction equipment are arriving from locations with known invasive vegetation problems, establish a controlled inspection and cleaning area to visually inspect arriving construction equipment to clean the vehicles to remove and collect noxious weed seeds that may be adhering to tires and other equipment surfaces.
  • Where feasible, (e.g., within ROWs), initiate interim site reclamation activities as soon as possible after construction activities are completed. Reclaim these areas using weed-free native shrubs, grasses, and forbs. Use local designed seed mixes in re-vegetation/stabilization efforts. Where feasible, revegetate the project area with grasses or forbs to limit dust generation.


  • Depending on the ecological resources present, consider steps to minimize the amount of vehicular traffic and human activity.
  • Report observations of potential wildlife problems, including wildlife mortality, to the appropriate wildlife agency.
  • Use drip pans during refueling to contain accidental releases.

Decommissioning/Site Reclamation

  • Remove all aboveground structures from the site.
  • Backfill any foundations, pits, and trenches, preferably with excess excavation material generated during prior ground-disturbing activities.
  • Use topsoil removed during the beginning of the project or during decommissioning activities to reclaim disturbed areas.
  • Reestablish the original grade and drainage pattern to the extent practicable.
  • Implement the site reclamation plan. For example:
    • Reclaim all areas of disturbed soil using weed-free native shrubs, grasses, and forbs.
    • Restore the vegetation cover, composition, and diversity to values commensurate with the ecological setting.
    • Review reclamation efforts and weed control periodically until the site is determined to have been successfully reclaimed.