An environmental-impact study released in November proposes 6,000 miles of corridors encompassing more than 3 million acres in California, Nevada, Arizona, Utah, Colorado, Idaho, Montana, New Mexico, Oregon, Washington and Wyoming.

A joint effort by the Bureau of Land Management, the Forest Service and the Energy and Defense departments, the study maps and performs an overall environmental evaluation of energy highways for new electric transmission lines and oil and gas pipelines.

As mandated by the Energy Policy Act of 2005, the EIS will result in automatic amendments to federal land management plans. However, proposals for new pipeline projects, transmission lines or utility retrofits will be analyzed in separate environmental studies that also will include the public.

Officials say the study will allow government agencies to help improve supply and distribution of affordable energy, eliminate redundancy in environmental-compliance actions and allow for quicker approvals of large-scale energy projects.

But conservationists fear the top-down analysis will run roughshod over canyons, rivers and world-class scenery. As mapped, one corridor would run past the entrances to Arches National Park and continue through the narrow Moab Canyon to the south.

Fourteen of the DOE's proposed corridors are in Utah, and would be anywhere from two-thirds of a mile to four miles wide. Each corridor could hold as many as nine electric transmission lines, 35 petroleum and 29 natural gas pipelines.

- Patty Henetz