Environmental Approach

Best Practices

Environmental best management practices are an integral part of the Flight Safety Corridor Program’s overall design. The following objectives are used by the Port to ensure that individualized removal and replanting plans are carefully executed and consistent with the environmental characteristics of each location.

Removal and Reforestation Objectives

Minimize disturbance and stabilize sites quickly
  • Prohibit vehicles or ground disturbance in wetlands
  • Leave stumps in place in wetlands and steep slopes
  • Leave vegetative buffers near streets and buildings
  • Protect existing native vegetation
  • Implement construction best management practices (spill prevention, erosion control, machinery leaks)
  • Plant extra trees to account for expected planting mortality
  • Avoid construction during bird nesting period
Avoid creating future aviation hazards
  • Replant densely planted trees and shrubs to inhibit natural tree recruitment
  • Replant shorter tree species
  • Replant native trees and shrubs
  • Replant species from the airport’s approved plant list
Improve overall site function by restoring native forest and shrub communities
  • Meet or exceed minimum tree replacement requirements
  • Remove all invasive species
  • Replant native species
  • Replant trees and shrubs densely
  • Replant a diversity of species
  • Minimize potential for future vegetation management needs

Restoring a Native Forest or Shrub Community


The Port will replant, at a minimum, one tree for every tree removed in non-critical areas and two trees for every tree removed in critical areas. In addition, the Port will replant cleared areas with native, low-growing, and compatible species such as these:

Ocean Spray
Holodiscus Discolor
Vine maple
Acer Circinatum
Redstem Ceanothus
Ceanothus Sanguineus
Mock Orange
Philadelphus Lewisii
Ninebark, Pacific
Physocarpus Capitatuss
Nootka Rose
Rosa Nutkana
Red Flowering Currant
Ribes Sanguineum
Wilder Cluster Rose
Rosa Gymnocarpa
Scouler’s Willow
Salix Scouleriana
Shore Pine
Pinus contorta
Oregon Ash
Fraxinus Latifolia
Red Alder
Alnus Rubra
Pacific Willow
Salix lucida

Wetland & Habitat Restoration Projects

The Port of Seattle undertakes fish and wildlife habitat restoration projects to compensate for the ecological impacts of development projects and to support voluntary stewardship actions. To date, the Port has completed the following ecological enhancements that made significant contributions to regional stewardship initiatives:

  • Created and enhanced 177 acres of wetland, including 350,000 new trees and shrubs
  • Enhanced two miles of stream habitat
  • Restored more than 30 acres of intertidal and saltwater habitat

The following two mitigation sites are prime examples of the Port’s commitment to environmental stewardship.

Auburn Mitigation Site

Birds near the airport present a hazard to airplanes, so the Port created and enhanced 65 acres of off-site wetland and wetland buffer adjacent to the Green River in Auburn. The Auburn site includes four ponds where waterfowl can nest, forage for food and find protection from predators.


Airport Mitigation Site

Adjacent to Sea-Tac Airport, the Port constructed 112 acres of wetland, enhanced about two miles of stream habitat, excavated 60-acre feet of floodplain storage capacity, and planted about 350,000 native trees and shrubs. Stream mitigation centered on improving fish habitat with 200 pieces of large woody debris, removal of culverts that blocked fish passage, and stabilization of four eroded portions of stream channel.

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