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Environmental guidance for planning studies

Use this guidance to incorporate environmental considerations in planning studies.

You can use this best practice example (PDF 163KB) as a template.

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

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

Planning and Environmental Linkages (PEL)

Planning and Environmental Linkages (PEL) studies integrate environmental, community and economic considerations early in the transportation planning process. Unlike standard planning studies, PEL efforts are typically federally led or closely coordinated with federal agencies and are intended to inform future NEPA decisions. This approach supports more efficient project delivery by reducing duplication between planning studies and the environmental review process. For more information, visit the Planning and Environmental Linkages webpage.

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. At the planning level, we focus on identifying key environmental features that may influence future decisions.

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 this is a pre-design effort or a study leading to a defined project, work with regional environmental staff to determine the likely environmental classification. Contact the appropriate region or modal environmental manager or our HQ NEPA/SEPA program for assistance. Region environmental offices and the NEPA/SEPA program can also review planning-level consultant scopes of work.

Notes:

  • The considerations described below are intended for planning studies and are not expected to include all environmental information required at the project level. This guidance establishes a baseline with flexibility to scale based on the scope and complexity of the plan. Each discipline includes subject matter expert contact information to support planning study development. We are developing updated documentation guidance to reflect 2025 federal policy changes. See the Environmental Guidance webpage for a more detailed list of environmental disciplines evaluated during project-level environmental review. 
  • Planning studies do not currently require state-level environmental justice assessments (EJAs) under the Healthy Environment for All (HEAL) Act. Federal environmental justice (EJ) considerations are no longer included in federal environmental documentation under the National Environmental Policy Act (NEPA). However, NEPA does consider social and community effects (SCE), which is not required at the planning level. See the Social and Community Effects section below for more information.

Fish passage barriers

In planning, we consider fish barrier correction for any future project that crosses a stream and alters the roadway prism or adds infrastructure within the existing right of way. Additionally, we must protect and maintain passable culverts and any previously corrected barriers to ensure water crossing structures remain passable.

Our Fish Passage Inventory Web map can be used to find information about completed, current and upcoming fish passage work. Fish passage data is also available in the GIS Workbench.

Our internal Fish Passage Site Management Application can be used to find site descriptions and project information, determine fish barrier status, generate reports and view photos of fish passage sites. This database is accessible to all WSDOT staff. 

While information is available through our fish passage web map and application, culvert inventories may be outdated or incomplete. Updating fish passage inventories during planning helps identify future funding needs. Contact ESO’s Stream Restoration Program for assistance with assessing fish passage needs and request an updated fish passage inventory within the plan study area.

GIS workbench layers

  • Business Area: Environmental
  • Fish > Fish Passage Inventory

Web tools

WSDOT Fish Passage Inventory Web Map

Contact

Contact the Stream Restoration Program Team 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. We monitor many of these important assets for more than 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

Contact

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

Chronic environmental deficiencies (CED)

Our CED program identifies locations along Washington’s state highways where frequent emergency repairs or maintenance harm fish habitat. The program was established as a commitment to Washington State Department of Fish and Wildlife (WDFW) to track these sites and implement long term nature-based projects that protect state highways, reduce impacts to fish from frequent repairs and increase the safety and resilience of our transportation system.

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

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
Federal level

Contact

Contact the region or modal Cultural Resources Specialist or the Cultural Resources Program Supervisor 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 which affect fish habitat and increases erosion. 

We construct and maintain stormwater BMPs to reduce the impact of stormwater runoff from our transportation system. At the planning level, we identify existing BMPs and areas where future projects may need to protect or replace existing BMPs. 

When planning efforts identify areas where future projects may expand or replace impervious surfaces or overlap with priority retrofit areas, this information should be noted to help anticipate potential stormwater BMP needs in later project development. Planning-level screening should also identify opportunities where stormwater retrofits may be feasible, regardless of legal requirement, particularly in areas with high priority stormwater retrofit segments within its limits. These early considerations help inform future project scoping and support evaluation of cost-effective stormwater improvements where appropriate.

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 future projects with project-driven 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

Impaired Waters and Total Maximum Daily Loads (TMDLs) 

At the planning level, it is important to identify whether a study area overlaps with potential discharges and outfalls to impaired surface waters to prepare for the different requirements that may be triggered in later phases (e.g., design, permitting, construction and maintenance). 

Impaired surface waters are water body segments (assessment units) in these Water Quality Assessment (WQA) categories:

  • Category 5 (also known as the 303(d) list).
  • Category 4a (covered by an approved TMDL).
  • Category 4b (covered by an approved TMDL alternative).

The magnitude and extent of additional requirements will depend on different factors, such as:

  • The pollutant(s) of concern.
  • The proximity or connectivity of WSDOT infrastructure to the impaired water body.
  • Whether WSDOT was assigned a pollutant wasteload allocation (WLA) by the TMDL. 

TMDL implementation plans reflect contributions from many external partners and include environmental, community and economic goals in a watershed through which our highways transect. 

Planning studies should document any impaired surface waters within or near the study area as potential water quality constraints for future phases of work.

WSDOT’s GIS Workbench is updated as soon as practicable following approval of the Department of Ecology’s WQA, which occurs every two years. Due to this update cycle, there may be a lag in available data. Use Ecology’s tools to verify WQA data in the GIS Workbench, this information is available in both map and database format. 

GIS Workbench Layers

  •  Business Area: Environmental
  •  Water Quality > 303(d) Impaired Waters and TMDLs 

Ecology’s Web Tools 

Contact

Contact WSDOT’s Statewide TMDL Lead to verify information. 

Climate change-related effects

We consider climate change and potential extreme weather impacts in planning studies. Identify the climate change-related hazards, the type, locations, frequency and projected time horizon for and severity of any climate change-related effects. Refer to the Guidance for Considering Climate Change-Related Effects in WSDOT Plans and Studies on the Climate change-related effects webpage for more information.

GIS workbench layers

  • Business Area: Environmental
  • Climate > Climate Vulnerability Assessment

Web tools

See the Climate Change Related Effects Tools and Resources Matrix on the Climate change-related effects 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

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

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 - Highest Rank HCIP - Overview in the WSDOT GIS Workbench to locate any medium or high priority segments for Ecological Value (Eco Rank) or Wildlife-related Safety (Safety Rank) within or adjacent to the planning study area. These can be found by navigating to the Environmental Business Area of the WSDOT GIS Workbench, expanding the “Fish and Wildlife” folder, then the “Habitat Connectivity (Non-Sensitive)” folder and selecting the “HCIP – Highest Rank” data layer, or by accessing the Fish Passage Inventory Web Map. Information for both Ecological and Safety categories is contained in the attribute table of the Highest Rank layer. Alternatively, you can add these as independent layers from the Workbench (HCIP – Eco Rank or HCIP – Safety Rank).

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 study area. In the data request, please specify the highway(s) and milepost range(s) for the study 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 found in the “Fish and Wildlife” folder of the WSDOT Environmental 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

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.

Social and Community Effects

Social and community effects (SCE) is a discipline under NEPA. While consideration of SCE is not required at the planning level, you may choose to include SCE during planning because it allows for more inclusive plans that evaluate the needs of communities. This work helps future transportation projects understand the needs of communities earlier, which is valuable during the environmental analysis phase of project delivery. 

To evaluate and address SCE, we analyze impacts to neighborhoods, displacements and community cohesion. 

This analysis includes meaningfully engaging with impacted communities to provide access to agency decision-making. Engaging with communities during a planning study helps ensure that the study’s recommendations reflect the needs of those communities. The SCE analysis during planning should be right sized for the scope of the planning study.

There are tools and resources to help include SCE considerations in plans and planning studies. 

Web Tools and Resources

Contact

Contact the Social and Community Effects Subject Matter Expert for general support.

Contact the NWR Principal Community & Environmental Justice Planner to learn how you can consider SCE in plans and studies.

Contact the Office of Equity and Civil Rights (OECR) for assistance with Title VI compliance, including demographic data review, language access and ensuring meaningful engagement, please contact the OECR Title VI Team:

Work with region/mode Title VI Liaison, as they support OECR’s Title VI Team through coordination and communication on these matters and can provide technical support.

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