An essential element of decision-making for transportation projects is the consideration and analysis of the potential environmental impacts or effects (ecological, aesthetic, historic, cultural, economic, social, or health) of projects and actions under the National Environmental Policy Act (NEPA) and the Wisconsin Environmental Policy Act (WEPA). Under these acts, WisDOT has the responsibility to address and consider all project related impacts or effects. The examination of these impacts includes not only the project’s direct impacts, but also the potential indirect and cumulative effects. While direct impacts are generally easier to recognize, WisDOT must also examine project related effects that could occur sometime in the future, which may be more difficult to identify or see.
Federal regulations define direct, indirect and cumulate impacts/effects in CFR Sections 1508.7 and 1508.8. Direct impacts are caused by the project and occur at the same time and place as the project itself. An example is damage to a wetland due to the reconstruction of a bridge. Indirect effects are caused by the project but can be later in time or farther removed in distance from the project. An example of indirect effects of a new interchange project could include potential changes in land use such as a new gas station that would not have occurred without the interchange. A cumulative effect includes the compilation of all direct and indirect effects on a particular natural cultural, historic resource or population due to past, present, and future activities or actions from any governmental and/or private entity.
The guidance found below is primarily for practitioners in the development of analyses for indirect and cumulative effects of the Wisconsin Department of Transportation's (WisDOT) proposed transportation projects. Additional resources are listed to provide more in depth information about indirect and cumulative effects.