Environmental guidance for planning studies

Use the guidance on this page to document environmental information, analysis and products during transportation planning for highway corridor and modal facility plans.

Find guidance regarding Federal Planning and Environmental Linkages (PEL) at the bottom of this page.

For statewide, regional or modal plans, contact the appropriate region or modal environmental manager (PDF 52KB) and WSDOT’s National/State Environmental Policy Act NEPA/SEPA program to tailor your efforts.

Before you start

Read Environmental Manual Chapter 200: Environmental Considerations in Transportation Planning (PDF 274KB) for legal requirements and policy context.

Environmental screening

Conduct an environmental screening to ensure that environmental context and priorities inform the plan’s practical recommendations. We encourage planners to collect information on the following key environmental assets that WSDOT must maintain in good condition, and other long-term considerations.

Note: this list does not include all environmental information considered at the project level. Agency staff can access the suggested data layers through our internal GIS workbench in the Environmental section.

Refer to the following guidance and contact the appropriate region or modal environmental manager (PDF 52KB) and WSDOT’s NEPA/SEPA program for assistance.

Environmental justice

WSDOT Plans and Studies are expected to address questions of equity and environmental justice. There are a variety of tools and resources to help you in this work. Refer to the Environmental Services Office environmental justice guidance and the Office of Equity and Civil Rights environmental justice guidance for additional information.

Fish passage barriers

We consider fish barriers for any future project that alters the roadway prism or adds infrastructure within the existing right of way. Protect and maintain any previously corrected barriers.

Use the ‘WSDOT Sites’ data layer in our GIS Workbench to locate fish passage barriers and corrected barriers within or adjacent to the planning study area.

Contact WSDOT’s Stream Restoration program manager to verify information and determine if the fish passage inventory needs an update. Updating fish passage inventories during planning helps us identify future funding needs.

Wetland and other environmental mitigation sites

We construct environmental mitigation sites to compensate for impacts to wetlands and other sensitive areas that cannot be avoided. We must monitor many of these important assets for 10+ years and protect them in perpetuity.

Use the ‘Environmental Mitigation Sites’ data layer in our GIS Workbench or on the WSDOT Online Map Center to locate environmental mitigation sites within the planning study area.

Contact WSDOT’s Region or Modal environmental manager or Wetland program manager to verify information. Consider additional wetland information later as project-level information develops using guidance on the Wetlands & other waters webpage.

Chronic environmental deficiencies (CED)

We track locations along state highways where frequent maintenance repairs of eroding streambanks can harm fish habitat. We design long-term fixes that reduce the impacts on fish and fish habitat adjacent to highways while increasing the safety and resiliency of highways.

Use the ‘Chronic Environmental Deficiencies, WSDOT’ data layer in our GIS Workbench to locate any CED sites within the planning study area.

Use CED information to propose practical long-term solutions that address active CED sites and protect resolved CED sites. Contact WSDOT’s CED coordinator to verify information.

Noise walls

We build and maintain noise walls to reduce the level of road noise. We maintain them in perpetuity, unless moved to accommodate future projects. We may propose retrofit noise walls in priority areas if funding is available.

Use the ‘Noise Walls, Built’ and ‘Noise Walls, Proposed’ data layer in our GIS Workbench to locate existing and proposed retrofit noise walls within the planning study area.

Contact WSDOT’s Air, Noise and Energy manager to verify information.

Historic bridges

We protect and maintain state-owned bridges on, or eligible for, the National Register of Historic Places. We consider other cultural and historic resources as project-level information develops.

Use the ‘WSDOT Historic Bridges’ data layer in our GIS Workbench to locate historic bridges within the planning study area.

Contact WSDOT’s Historic and Cultural Resources specialist to verify information.

Stormwater best management practice (BMP) sites and retrofit priorities

We construct and maintain stormwater BMPs to reduce the impacts of stormwater runoff from paved surfaces. Future projects must protect or replace existing BMPs. Projects that expand impervious surfaces or are within priority retrofit areas may require new BMPs.

Use the ‘Stormwater Features, BMPs’ data layer in our GIS Workbench to locate BMP sites within the planning study area.

Contact WSDOT’s Stormwater Features manager to locate any medium or high retrofit priorities within the planning study area and to verify all stormwater information.

Climate vulnerability

We consider climate change and extreme weather impacts.

Use the ‘CIVA – Climate Vulnerability Assessment’ data layer in our GIS workbench to locate WSDOT assets within the planning study area with medium or high vulnerability to climate threats. Consult with local planning partners to determine availability of additional area-specific climate data.

Use this information to document how climate change and extreme weather vulnerability are considered. Propose practical long-term solutions that improve the resilience of the transportation system in the planning area.

Contact WSDOT’s NEPA/SEPA program to verify information. Refer to Guidance for considering impacts of climate change in WSDOT plans (PDF 606KB).

Habitat connectivity

We prioritize opportunities that protect fish, wildlife and habitat resources and reduce collisions between wildlife and vehicles along state highways.

Use the ‘Habitat Connectivity – Maximum Rank, Non-Sensitive’ data layer in our GIS Workbench to locate any medium or high priority segments for Ecological Stewardship Rank or Wildlife-related Safety Rank within or adjacent to the planning study area.

Use the ‘Pollinator Habitat Rankings’ data layer in our GIS Workbench to locate any medium, high or very high priority segments for Pollinator Habitat Rank, Urban Gateway Habitat Rank or Monarch Habitat Rank within or adjacent to the planning study area.

Use this information to propose practical solutions for improving habitat connectivity. Contact WSDOT’s Habitat Connectivity biologist to verify information.

Hazardous materials contamination sites

Review known contaminated sites to ensure that those sites do not impact, or become impacted by, our future projects.

Use the Washington State Department of Ecology’s Toxics Cleanup map application to locate contaminated sites in the planning study area. Document sites with any of the following statuses:

  • Awaiting cleanup
  • Cleanup started
  • Monitoring cleanup progress

Contact WSDOT’s Hazmat Program Manager to verify information and discuss strategies for addressing contaminated sites in future projects.

Planning and Environmental Linkages (PEL)

Planning and Environmental Linkages (PEL) studies consider environmental, community, and economic goals early in the transportation planning process. This can create more efficient outcomes for project delivery by eliminating duplication of effort between planning studies and the environmental review process. More information on PEL

Slow down – lives are on the line. 

In 2023, speeding continued to be a top reason for work zone crashes.

Even one life lost is too many.

Fatal work zone crashes doubled in 2023 - Washington had 10 fatal work zone crashes on state roads.

It's in EVERYONE’S best interest.

95% of people hurt in work zones are drivers, their passengers or passing pedestrians, not just our road crews.