Environmental disciplines

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Environmental regulations across a range of disciplines ensure the work of building and maintaining our transportation system does supports our communities and environment. Much of the environmental work we do at the Washington State Department of Transportation (WSDOT) is organized into the following disciplines. Additional information is also available on our NEPA & SEPA or Permits & approvals pages.

Air quality, noise, and energy

Air quality, noise, and energy analyses address emissions from vehicles, noise generated on our roadways, and energy used in our transportation system. In addition, WSDOT considers the greenhouse gas emissions from our projects in project documentation.

Find what you need to be in compliance with air, noise, and energy state and federal regulations.

Cultural resources

Cultural resources include archaeological sites; historic buildings, roads, and bridges; and places on the landscape that are historically significant to Washington State. The Cultural Resources program works to preserve this rich and diverse cultural heritage while balancing the state’s transportation needs.

Find what you need to comply with a number of different state and federal laws that guide how WSDOT addresses cultural resources. View highlights of Washington’s most historically significant transportations structures and results of creative mitigation efforts.

Fish & wildlife

Biologists at WSDOT work to protect fish, wildlife, and habitat resources from the impacts of transportation projects. Find the information you need to be in compliance with federal and state regulations, wildlife research relevant to transportation, and training for authors of biological assessments.

Hazardous materials

Hazardous materials may include lead, creosote, asbestos, chemically contaminated sediment, releases from underground storage tanks, or other solid waste that may be encountered or generated by our transportation projects.

Find information on how to investigate, sample, and comply with local and federal laws to safely manage and dispose of hazardous materials through early planning and coordination with WSDOT staff, contractors, and regulators.

Social & community

Learn how to consider social and community effects of a project under the National Environmental Policy Act (NEPA) and the State Environmental Policy Act (SEPA).

Stream restoration

Correcting high priority fish passage barriers and repetitive stream bank and shoreline erosion problems, also known as chronic environmental deficiency (CED) sites, reduces the state transportation system’s impact on fish and fish habitat. 

Water resources & erosion control

Managing the affects our daily activities and construction projects have on groundwater and surface water helps WSDOT protect and improve water quality and habitat.

Find what you need to comply with groundwater, surface water, stormwater, and floodplain regulations, identify geologic conditions, and develop discipline reports for these topics. Also, find recent research and reports documenting activities required by stormwater permits.


Wetlands consist of any lands where soil is at least periodically covered by water, including rivers, lakes, streams, and estuaries. WSDOT works to prevent net loss of wetlands and minimize impacts if they are unavoidable during the development of transportation project.

Find information to complete wetland assessments, delineations, and learn about options for mitigating impacts to wetlands

Learn how to consider land use impacts of a project under the National Environmental Policy Act (NEPA) and the State Environmental Policy Act (SEPA). This page provides guidance on the following aspects of the environment considered under NEPA and SEPA.

How to prepare indirect effects and cumulative impacts analyses for projects requiring an Environmental Assessment (EA) or an Environmental Impact Statement (EIS).