Skip navigation
Tribal Energy and Environmental Information Clearinghouse
Tribal Energy and Environmental Information Clearinghouse: Environmental resources for tribal energy development
Energy Resources Assessments & Monitoring Laws & Regulations
Energy Resources Assessments & Monitoring Laws & Regulations |  Home  |  News  |  FAQ  |  Glossary
Document Library
Federal and Tribal Contacts

Ecological Mitigation Measures

Mitigation measures to avoid or reduce ecological impacts from hydrokinetic 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 activities (e.g., seabed disturbance, land and underwater disturbance, habitat destruction) and project emissions (e.g., fugitive dust, air pollution releases, noise, water releases). Many impacts can be reduced or avoided when considered during the siting and design phase.

Develop a final set of mitigation measures for the project in consultation with the appropriate tribal, federal, and state resource management agencies, and with stakeholders. Conduct these consultations as part of the project development process, 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 in order to locate site facilities away from important ecological resources (e.g., known mating and feeding areas, migratory routes, kelp beds and aquatic vegetation, wetlands, important upland habitats, sensitive species populations).
  • Ensure protection of important resources by establishing protective buffers to exclude unintentional disturbance.
  • Vessels should travel at reduced speed and maintain reasonable distance when marine mammals are present.
  • Allowance of sufficient turbine spacing will enhance fish avoidance.
  • Use existing facilities and disturbed areas (e.g., ports, access roads, graded areas) to the extent possible to minimize the amount of new disturbance. Configure new access roads and rights-of-way (ROWs) 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-disturbing 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 mulch. Prohibit the use of fill materials from areas with known invasive weed populations.
  • Minimize the amount of land disturbance and develop and implement stringent erosion and dust control practices.
  • Develop an offshore and onshore spill management plan.
  • Develop site fencing in conjunction with appropriate natural resource agencies to either allow or prevent site access by wildlife species.

General Mitigation Measures

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

  • Educate workers regarding the occurrence of important resources in the area and the importance of their protection, including the applicable regulatory requirements.
  • Schedule activities to avoid disturbance of resources during critical periods of the day (e.g., nightime) or year (e.g., periods of courtship, migration, 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.
  • Establish buffer zones around raptor nests, sea turtle 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. Undertake reclamation activities as early as possible on disturbed areas.
  • Regularly monitor the project site for invasive 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 fugitive dust.
  • Apply spill prevention practices and response actions both offshore and onshore in refueling and vehicle-use areas to minimize accidental contamination of habitats.
  • Address spills immediately per the appropriate spill management plan, and initiate water or soil cleanup and soil removal if needed.
  • Turn off all unnecessary lighting at night to avoid attracting migratory birds and disorienting sea turtle hatchlings.
  • Require the use of certified weed-free mulch.
  • Prohibit the use of fill materials from areas with known invasive weed populations.
  • Implement stringent erosion and dust control practices.

Project Phase-Specific Mitigation Measures

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


  • Maintain noise-reduction devices (e.g., mufflers) in good working order on vehicles and construction equipment.
  • Employ a bubble curtain during pile driving to reduce underwater noise transmission.
  • Post at least one qualified mammal observer during construction.
  • Refuel in a designated fueling area in the port or at the onshore site 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.
  • Establish a controlled inspection and cleaning area to visually inspect arriving construction equipment in order to clean the vehicles to remove and collect noxious weed seeds that may be adhering to tires and other equipment surfaces.
  • 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.


  • Report potential wildlife problems, including wildlife mortality, to the appropriate wildlife agency.

Decommissioning/Site Reclamation

  • Use cutting rather than explosives to remove mooring structures.
  • Leave fixed structures on the seafloor or riverbed if removal would cause more damage than leaving in place.
  • Gradually remove wave and tidal energy devices in stages if used by seals and seal lions for haul-out.
  • Implement the site reclamation plan.
  • Review reclamation and weed control efforts periodically until it is determined that the site has been successfully reclaimed.