National Environmental Policy Act

As concern for environmental problems grew during the 1960s, the need for better project planning to prevent environmental degradation became obvious. Too many projects (e.g., dams, power plants, highways) had been built without regard for their negative impacts on water quality, soil erosion, aquatic and terrestrial habitat , or negative economic and social impacts on nearby communities. Many of these projects caused irreversible harm to the environment . Congress recognized that federal projects were

The National Environmental Policy Act is intended to promote environmental considerations into federal agencies' decision-making processes. Impacts on wetland systems (shown here) often are the subject of NEPArelated processes.
The National Environmental Policy Act is intended to promote environmental considerations into federal agencies' decision-making processes. Impacts on wetland systems (shown here) often are the subject of NEPArelated processes.
culprits of environmental degradation, and that federal and state agencies would continue to support such projects unless Congressional statute forced them to consider their negative environmental impacts.

The National Environmental Policy Act (NEPA) of 1969 requires all federal agencies to use an interdisciplinary approach in their project planning and decision-making. Because federal agencies had no history or desire to work together on projects, tried to protect their "turf," and did not want the expense of the environmental impact assessment process to affect their budgets, they initially fought with Congress to prevent NEPA from being enacted. But since that time, every federal agency has developed a set of NEPA guidelines for its personnel to follow.

NEPA Components and Requirements

The National Environmental Policy Act has several major requirements. First, it provides a comprehensive approach to environmental protection by requiring that federally funded or federally permitted projects must perform environmental impact assessments and write an environmental impact statement (EIS) if that project would have a potentially significant environmental impact. An environmental assessment (EA) is conducted to determine whether impacts are potentially significant.

The EIS must describe:

  • The proposed action;
  • Various environmental impacts of the proposed action;
  • Unavoidable adverse environmental effects of the action;
  • Alternatives (and their negative impacts) to the proposed action; and
  • Long-term environmental damages.

Alternatives often give decisionmakers methods to mitigate some negative project impacts or carry out actions entirely different than those originally planned. For example, the city of Denver, Colorado proposed the Two Forks Dam to obtain additional water supplies. In 1989, the U.S. Environmental Protection Agency denied approval when one EIS alternative suggested making Denver meter all buildings and houses in order to stop wasting the water it already had.

Research for environmental impact assessments is done in categories such as: land use and development; social and economic effects; relocations and neighborhood effects; noise; traffic; transportation; environmental health and public safety; historical and archaeological resources; visual resources; air quality; water resources (including wetlands ); wildlife and aquatic species and their habitats; floodplains; and coastal areas. Because of its complexity and comprehensive nature, the research is expensive. EISs for large projects typically cost tens of millions of dollars and take years to complete.

To ensure public participation, the public is notified when the draft EIS (DEIS) is published; all notices regarding NEPA processes are published in the Federal Register. The public and special interest groups typically have 45 to 60 days to read and comment on it, either in writing or at public hearings. Federal agencies must incorporate public comment into the final EIS (FEIS). The FEIS states which of the alternatives has been chosen for implementation, and the justifications for selecting that alternative over the others.

Visionary Scope.

NEPA is important to water resources management because the assessment done for the water resources portion of an EIS helps decisionmakers balance the numerous and complex variables when considering a project. They must take into account how their project can have a ripple effect on water resources, wildlife, habitat, and local communities. An EIS helps illustrate that water resources must be managed not only for immediate human uses, but for long-term ecosystem sustainability. For example, a recent controversy over how to manage the Missouri River is pitting the interests of upstream recreational economies and their necessary habitat preservation with downstream economic interests of barge traffic and flood control.


Laurel E. Phoenix


Marriott, Betty Bowers. Environmental Impact Assessment: A Practical Guide. New York: McGraw-Hill, 1997.

Reimold, Robert J. Watershed Management: Practice, Policies, and Coordination. New York: McGraw Hill, 1998.

Rogers, Peter. America's Water: Federal Roles and Responsibilities. Cambridge, MA: MIT Press, 1993.

Internet Resources

Council on Environmental Quality. <> .

Federal Register. U.S. Government Printing Office. <> .

U.S. Government's NEPAnet. <> .


The National Environmental Policy Act (NEPA) created the Council on Environmental Quality and placed it in the Executive Office of the President. The council oversees implementation of NEPA, advises the president on environmental issues, and writes an annual report evaluating national environmental conditions and trends, and regulatory adequacy to protect the environment.

User Contributions:

Comment about this article, ask questions, or add new information about this topic:


National Environmental Policy Act forum