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From Open Energy Information

Transmission Fisheries Resources

Fisheries Resources
Present, Potentially Affected

The Fish and Wildlife Coordination Act (16 USC 661 et seq.) mandates consultation with the U.S. Fish and Wildlife Service (USFWS), the state fish and wildlife entities, and occasionally National Oceanic and Atmospheric Administration before beginning transmission line siting. Impacts and mitigation measures are reviewed to see if the actions are appropriate for the species in that area.


Fisheries Resources Impacts & Mitigation

Transmission line development projects impact fisheries with sediment runoff, construction in riparian areas, water diversion, and accidental spills. These impacts affect spawning, keystone habits, and fish population. Certain species rely on spawning grounds and specific conditions to reproduce. Waterway diversion and habitat alterations can also inhibit these processes.

Use the following mitigation measures to decrease the impacts from transmission line projects:

Runoff/Water Diversion/Sediment

  • Observe natural drainage controls and patterns to minimize the project area and decrease fish habitat disturbances. During the dry season, install fords and remove any barriers in the streambed to mitigate high sediment levels downstream.
  • Only use rocked, low water fords during the driest time of the year and as a last alternative. Restore the preexisting stream channel, including bed and banks.
  • Construct culverts to withstand a 100-year flood event.
  • Where access roads cross a dry wash, grade the road to reflect a 0% slope to mitigate high runoff flows.


  • To mitigate hazardous material spills in nearby streams, refrain from storing, transferring, or mixing oils and fuels.
  • Maintain a Spill Prevention and Contingency Plan to include procedures for hazardous materials storage, construction refueling stations and locations, and spill containment and recovery plans.

Trucks Use

  • To decrease fuel spills, equip fueling stations with a secondary containment for on-site fueling tanks.
  • Create buffers between fueling stations and dry or flowing streams to decrease hazardous fluid contamination.
  • Keep vehicles and equipment in good-working order to prevent oil and fuel leaks.


  • To decrease long-term wear on access roads, culverts, and sediment control measures, perform regular inspections and maintenance.
  • Minimize impacts to sensitive fish habitats by prohibiting paint or permanent discoloring agents for construction to rocks, vegetation, structures, and fences.
  • To reduce traffic in areas with high erosion and stream sedimentation, require all construction-vehicles outside the right-of-way to follow pre-designated access roads, contractor-acquired access roads, public roads, or overland travel routes.
  • Place towers outside of stream riparian areas and avoid cutting vegetation by utilizing natural landscape features to span the conductor over existing shrub and tree riparian zones.
  • Construct new access roads outside of stream riparian areas.
  • Build staging areas away from streambeds and riparian areas.
  • To decrease fish disturbances, isolate in-water work areas and concentrate catch and release practices. Use appropriate fish screens on all intakes and pumps.
  • Regularly inspect and maintain access roads, culverts, and sediment control measure conditions to mitigate erosion and runoff during operation and maintenance activities.
  • Decrease riparian erosion with jute netting, silt fences, and dam maintenance. Reclaim disturbed soil using weed-free native grasses, forbs, and shrubs.
  • Use dust abatement techniques on unpaved and vegetation free surfaces to mitigate fugitive dust in aquatic habitats.
  • To mitigate pipe leaks, use double-walled pipelines to transport liquids across river or streams containing fish.
  • Design transmission lines to cross streams at right angles, at points of narrowest width, and/or at the lowest banks to decrease stream corridor habitat impacts.


  • To reduce aesthetic impacts, use single circuits (without arms) on poles. Double circuits can also be used to prevent additional clearing to install new lines. When available, utilize other linear features.
  • Trim trees and shrubs rather than clearing areas to maintain aesthetic qualities and decrease habitat fragmentation.

Hazardous material

  • Remove and send all construction waste, including trash and litter, garbage, and petroleum products to an authorized disposal facility. This will mitigate spill potentials and aquatic exposure to these materials.


  • Spawning typically occurs from July 1 to September 1. Refrain from culvert installation and or replacement, and stream bank stabilization. Fording streams at existing crossings and roads (e.g., dip, culvert, bridge) is exempt.

Riparian areas

  • When salmonid eggs or alevins are present in gravels, avoid blasting near streambeds to decrease impacts to fish regeneration.

Factors Affecting Fisheries Resources

Riparian areas provide opportunities for less common species to thrive in otherwise nonreplicable conditions. Specific species adaptions demand seasonal environments to reproduce. Biodiversity maintains a balanced ecosystem, which decreases the likelihood of single species depletion.

Vernal pools are seasonal depressional wetlands or shallow, stagnant streambeds that range in size from small puddles to large lakes. Some vernal pools are connected by drainages, called swales, to form larger vernal complexes. Hard clay or bedrock lines the pools to retain the runoff or rain collection. These pools create a unique biota for fish, frog, and salamander eggs or tadpoles, amongst rare plants. These delicate ecosystems enable rare, threatened, and endangered species to thrive.