Environmental guidance for planning studies

The statewide transportation planning process requires transportation agencies to protect and enhance environmental consideration in the planning process (23 CFR 450.206(a)(5)). 

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

For statewide, regional or modal plans, contact the Environmental Service Office’s National/State Environmental Policy Act (NEPA/SEPA) Program to tailor your efforts.

Before you start

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

Agency staff can access the suggested environmental data layers through our internal GIS workbench or interactive web mapping applications referenced in each discipline section below. Contact HQ Environmental Services Office Environmental Information Program for assistance with the GIS workbench. 

Environmental screening

Conduct an environmental screening to ensure that environmental context and priorities inform the plan’s practical recommendations. We encourage planners to gather information on the following essential environmental elements that WSDOT must maintain in good condition. Many of the data layers described below are also available in the Community Planning Portal, where you can analyze them using web tools that function similarly to ArcGIS Pro desktop applications.

This level of environmental screening should: 

• Identify existing environmental assets that must be protected.
• Detect other key environmental factors that have the potential to influence the scope of future investments.
• Determine if additional environmental review is necessary prior to project development. 

If a planning effort may lead to a defined project, please work with your regional environmental staff to determine the likely environmental classification. Refer to the following guidance and contact the appropriate region or modal environmental manager or our HQ NEPA/SEPA program for assistance with the environmental screening or environmental classification, if working on a defined project.

Note: The list below is intended for planning studies, which are not required to include all environmental information considered at the project level. Each discipline below includes subject matter expert contact information to support planning study development. WSDOT is developing documentation guidance to reflect 2025 federal policy changes which may be included on this page when they become available. See the Environmental Guidance webpage for a more detailed list of environmental disciplines evaluated during project-level environmental review. 

Fish passage barriers

We consider fish barrier correction for any future project that alters the roadway prism or adds infrastructure within the existing right of way. The process for determining when to include barrier correction in transportation projects includes protecting and maintaining passable culverts and any previously corrected barriers to ensure water crossing structures remain passable.  

Use the ‘Culverts with Fish Use’ layer and the ‘Delivery Plan’ layers in our Fish Passage Inventory Web map to locate fish passage barriers and corrected barriers within or adjacent to the planning study area. You can also view the data in the GIS Workbench.

Use our internal Fish Passage Site Management Application to find site descriptions and project information, determine fish barrier status, generate reports, and view photos of fish passage sites. 

Updating fish passage inventories during planning helps identify future funding needs. 

GIS workbench layers

Contact the Stream Restoration Program Manager for the correct GIS layers.

Web tools

WSDOT Fish Passage Inventory Web Map

Contact

Contact the Stream Restoration Program Manager to verify information or determine if the fish passage inventory needs an update.

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. WSDOT must monitor many of these important assets for 10+ years and protect them in perpetuity.

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

Consider additional wetland information later as project-level information develops using guidance on the Wetlands & other waters webpage.

GIS workbench layers

• Business Area: Environmental
• Wetlands > Environmental Mitigation Sites 

Web tools

• WSDOT Online Map Center
• WSDOT Environmental Mitigation Sites

Contact

Contact the region or modal environmental manager or Wetland Program Manager to verify information.

Chronic environmental deficiencies (CED)

WSDOT’s CED program identifies locations along state highways where frequent emergency repairs or maintenance activities harm fish habitat. The program was established as an obligation to Washington State Department of Fish and Wildlife (WDFW) to track these sites and implement long term projects that protect state highways, reduce impacts to fish from frequent repairs, and increase the safety and resiliency of state highways.

View the CED webpage to learn more about the CED program and process. Use the CED interactive map to locate any CEDs near the study area. Then contact the CED coordinator for additional information. In planning studies, include information on the status of the CED site, the nature of the CED problem, the assets involved, and any proposed solutions that WSDOT has committed to implementing. 

GIS workbench layers

• Business Area: Environmental
• Fish > Fish Passage Inventory > Chronic Environmental Deficiencies (CEDs)

Web tools

• CED webpage
• WSDOT Fish Passage and CED Interactive Web Map

Contact

Contact the CED Coordinator for details about any CEDs near the planning study area.

Noise walls

We build and maintain noise walls to reduce the level of road noise and maintain them in perpetuity. 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 the GIS Workbench to locate existing and proposed retrofit noise walls within the planning study area.

GIS workbench layers

• Business Area: Environmental
• Transportation Features > Noise Walls, Built
• Transportation Features > Noise Walls, Proposed
• Land Use – Land Cover > Statewide Parcels

Contact

Contact the 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 the GIS Workbench to locate historic bridges within the planning study area.

GIS workbench layers

• Business Area: Environmental
• Transportation Features > WSDOT Historic Bridges

Web tools

State level

• Washington State Historic Bridge List
• WSDOT Library WSDOT Library Digital Collections
• Washington Information System for Architectural and Archeological Records Data (WISARRD) 

Federal level

• National Bridge Inventory National Bridge Inventory - Management and Preservation - Bridges & Structures
• National Register Database NPGallery

Contact

Contact the Historic and Cultural Resources Specialist to verify information.

Stormwater best management practice (BMP) sites and retrofit priorities

Stormwater runoff is a significant source of pollution in Washington. Without treatment, stormwater runoff from the transportation system carries pollutants to nearby rivers and streams. Uncontrolled stormwater also changes the flow rates in streams that affects fish habitat and increases erosion. We construct and maintain stormwater BMPs to reduce the impacts of stormwater runoff from our transportation system. Future projects must protect or replace existing BMPs. Projects that expand or replace impervious surfaces, or are within priority retrofit areas, may require new BMPs. Projects that are not required by regulation to construct BMPs still have the opportunity to evaluate whether they may cost effectively reduce the impacts of stormwater through opportunity-based stormwater retrofits as part of the project work. If a project has a high priority stormwater retrofit segment within its limits, it would be a particularly good candidate for this type of retrofit consideration.

Use the ‘Stormwater Features, BMPs’ data layer in the GIS Workbench to locate existing BMP sites within the planning study area. Use WSDOT’s Stormwater Retrofit Prioritization Web Map to view high priority highway segments for scoping opportunistic and standalone stormwater retrofits. Any projects with project-triggered retrofit requirements as described in WSDOT’s Highway Runoff Manual would use the same Web Map view for opportunistic retrofits to determine whether the project is in a high priority area.

GIS workbench layers

• Business Area: Environmental
• Water Quality > Stormwater Data > Stormwater Features, BMPs

Web tools

WSDOT Stormwater Retrofit Prioritization Web Map

Contact

• Contact the Stormwater Features Manager for questions on existing BMP information.
• Contact the Stormwater Retrofit Outreach and Innovation Lead if you have questions related to the Stormwater Retrofit Prioritization Web Map and how to utilize the information

Climate vulnerability

We consider climate change and extreme weather impacts. Consideration of climate change-related effects should identify the climate change-related hazards, and type of, locations of, projected time horizon for and severity of climate-related impacts.

Use the ‘Climate Vulnerability Assessment’ data layer in the 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.

Refer to the Guidance for Considering Climate Change-Related Effects in WSDOT Plans and Studies on the Consideration of Climate Change webpage.

GIS workbench layers

• Business Area: Environmental
• Climate > Climate Vulnerability Assessment

Web tools

See the Climate Change Related Effects Tools and Resources Matrix on the Consideration of Climate Change webpage.

Contact

Contact the Climate Mitigation and Adaptation Branch at ClimateAdaptation@wsdot.wa.gov to verify information.

Air quality

We consider air quality at the planning level to ensure we are addressing federal and local policies. 

For transportation conformity, use the layers in the ‘Air Quality’ folder in the GIS Workbench to locate air quality maintenance and nonattainment areas within the planning study area. The Washington State Department of Ecology also publishes a map and table of Washington’s Air Quality Maintenance Areas.

Emissions from mobile source air toxics (MSATs) are influenced by vehicle miles traveled (VMT), fuel source, and engine efficiency. Additional consideration should be made for areas with high traffic volumes or high levels of diesel particulate matter in a single location. The WSDOT Traffic Counts can be used to help identify areas of potential concern.

GIS workbench layers

• Business Area: Environmental
• Air Quality > Carbon Monoxide (Service – ECY)
• Air Quality > Particulates (Service – ECY)

Web tools

• Washington’s Air Quality Maintenance Areas
• Map of Air Quality Monitors | US EPA
• WSDOT Traffic Counts

Contact

Contact the Air Quality Technical Lead to verify information and determine if the project requires an air quality analysis. 

Greenhouse gas emissions 

We prioritize assessing greenhouse gas emissions at the planning level. Reducing Vehicle Miles Travelled (VMT) is a key strategy to reducing transportation sector greenhouse gas emissions and is one of two identified strategies along with electrification in the state’s energy strategy. Planners should identify strategies to reduce VMT and increase other modes of transport such as transit, active transportation, demand and system management, and through strategic land use planning. A planning study can use the WSDOT Detailed Annual Mileage and Travel Data and the WSDOT Traffic Counts to understand the greenhouse gas environment. 

Web tools

• WSDOT Traffic Counts
• WSDOT Detailed Annual Mileage and Travel Data

Contact

Contact the Climate Change Technical Lead to determine how a climate change analysis should be completed.

Habitat connectivity

We prioritize opportunities that protect fish, wildlife, and habitat resources, taking a two-pronged approach to addressing wildlife connectivity concerns: 1) efforts intended to increase or maintain the permeability of the landscape to animal movements (increase habitat connectivity), and 2) those that are intended to reduce collisions between wildlife and vehicles along state highways. Early consideration of fish and wildlife habitat connectivity needs increases the likelihood that reasonable approaches to accommodating them can be incorporated into projects.

Use WSDOT’s Habitat Connectivity Investment Priorities to locate any medium or high priority segments for Ecological Stewardship (Eco Rank) or Wildlife-related Safety (Safety Rank) within or adjacent to the planning study area. These can be found by navigating to the ‘Habitat Connectivity – Maximum Rank, Non-Sensitive’ data layer in the GIS Workbench, or by accessing the Fish Passage Inventory Web Map.

If the planning study area includes medium or high priority segments for Ecological Stewardship, contact the Habitat Connectivity SME to discuss their implications. 

If the planning study area includes medium or high priority segments for Wildlife-related Safety, contact the Habitat Connectivity SME to obtain current wildlife carcass removal data for your project. In the data request, please specify the highway(s) and milepost range(s) for your project area. 

WSDOT’s Wildlife Carcass Removal Database is the authoritative carcass removal dataset, subjected to a rigorous validation process, and which includes:

• Wildlife carcass removals reported by WSDOT Maintenance staff.
• WDFW deer and elk salvage data (this is QA/QC’ed by WSDOT staff and rolled into the Wildlife Carcass Removal Database).
  • The “Source Code” and “Disposal” fields on provided data will indicate source, such as salvaged or WSDOT-reported.
• Verified wildlife carcass removals reported by external sources that were not included in either WSDOT- or WDFW-reported data.

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

Use this information to propose practical solutions for improving habitat connectivity. 

GIS workbench layers

• Business Area: Environmental
• Fish and Wildlife > Habitat Connectivity (Non-Sensitive) > Habitat Connectivity – Maximum Rank, Non-Sensitive
• Fish and Wildlife > Pollinator Habitat Rankings

Web tools

• Data can be accessed within the Fish Passage Inventory Web Map
• Other Features > Habitat Connectivity Investment Priorities 

Contact

Contact the Habitat Connectivity Biologist to verify information.

Hazardous materials contamination sites

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

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

• Awaiting cleanup
• Cleanup started
• Monitoring cleanup progress

Web tools

Toxics Cleanup Map

Contact

Contact the 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.