Environmental Data Viewer Disclaimer
The data presented is intended for use in WECC’s 10- and 20-year Transmission Expansion Plans, as well as by other organizations in their early stage transmission corridor planning efforts.
Siting-level analyses, while they may employ some of the same data sets as planning-level analyses, will also use other
project-specific data sets. Because of the scale at which the regional Transmission Expansion Planning process operates,
it is not possible or appropriate to consider all project-level data that could be critical during transmission line siting.
WECC recommends any potential transmission corridors generated through this mapping application be thoroughly reviewed
against siting-level data and any applicable laws and regulations.
WECC receives data used in its analyses from a wide variety of sources. WECC strives to source its data from reliable entities and undertakes reasonable efforts to validate the accuracy of the data used. WECC believes the data contained herein and used in its analyses is accurate and reliable. However, WECC disclaims any and all representations, guarantees, warranties, and liability for the information contained herein and any use thereof. Persons who use and rely on the information contained herein do so at their own risk.
Environmental Data Layer Description
To create the Environmental Risk Data shown on this mapping application, WECC applied a classification system to its catalogue of environmental data to calculate planning-level risks based on the environmental features of the landscape.
WECC’s Environmental Risk Class data was developed by a diverse group of transmission stakeholders (representing industry, government, and environmental interests) who collaborated to develop a method for including environmental concerns in the
regional transmission planning process. Details on that stakeholder process can be found in the document
Environmental Recommendations for Transmission Planning.
The Environmental Data Layer is a single GIS layer that identifies planning-level risk to transmission development based on environmental sensitivities and constraints, as defined by four risk categories:
Category 1 - Least Risk of Environmental or Cultural Resource Sensitivities and Constraints:
Areas with minimal identified environmental or cultural resource constraints and/or with existing land uses or
designations that are compatible with or encourage transmission development. These areas would present few or
minimal environmental and cultural mitigation requirements and are least likely to result in project delays.
Category 2 - Low to Moderate Risk of Environmental or Cultural Resource Sensitivities and Constraints:
Areas where development may encounter one or more environmental or cultural resource sensitivity areas or
constraints that would require low to moderate permit complexity or mitigation costs. This category also
includes areas in the Protected Areas Database of the United States (PAD-US) dataset that have an unknown
land use designation or degree of restriction to transmission development.
Category 3 - High Risk of Environmental or Cultural Resource Sensitivities and Constraints:
Transmission development is likely to encounter one or more environmental or cultural resource sensitivities or
constraints that would substantially increase permitting complexity and could result in project delays and high
Category 4 Areas Presently Precluded by Law or Regulation:
Areas where transmission development is presently precluded by federal, state, or provincial law, policy, or
regulation, as well as areas where development would represent a “fatal flaw” likely to preclude successful
project completion (e.g., identified Native American Traditional Cultural Properties and sacred sites).
Latest updates were completed in December, 2014. A complete list of area types can be viewed
Downloadable GIS Environmental Risk Class Data and the Environmental Data Products User's Manual
Mitigation Cost Study
Capital Cost Study