A draft environmental impact statement on how to operate the Glen Canyon Dam on the Colorado River for the next 20 years carries seven alternatives, none of which recommends the removal of the dam.

What it does propose is an operational plan that would continue to implement high-flow releases from the dam in a way to mimic the river's natural flows throughout the year, while also generating an amount of electricity equal to or greater than that currently produced.

Since the dam was finished in 1966, the wisdom of building it has been questioned. Agreeing to the project was David Brower, at the time executive director of the Sierra Club. He later wished he hadn't.

"Glen Canyon died, and I was partly responsible for its needless death," Brower wrote in The Place No One Knew, a Sierra Club book published in 1963. "Neither you nor I, nor anyone else, knew it well enough to insist that at all costs it should endure. When we began to find out it was too late."

There continue to be calls for the dam's decommissioning. The Glen Canyon Institute has a standing position that the "revealed landscape of Glen Canyon should be protected and the continued restoration of Glen Canyon should be facilitated and planned for. Lake Powell is unnecessary and enormously destructive, while Glen Canyon is America’s Lost National Park. The mission of Glen Canyon Institute is to restore a free-flowing river through Glen Canyon."

Daniel Beard, a former commissioner of the U.S. Bureau of Reclamation wrote an entire book on why the Glen Canyon Dam should be decommissioned.

"If lake levels continue to drop as the experts have predicted, the Bureau of Reclamation will not be in a position to produce any power because the lake levels will be below the intakes for the power generating facilities," he wrote in Deadbeat Dams, Why We Should Abolish the U.S. Bureau of Reclamation and Tear Down Glen Canyon Dam, which was published last year. "When the reservoirs drop to within fifty feet of the generator intakes, air begins to be entrainced in the water, which will cause cavitation in the turbines. This will lead to turbine failure and potentially catastrophic situations.

"The current state of affairs at Glen Canyon Dam leads me to conclude that we should remove Glen Canyon Dam, drain Lake Powell, and allow the Colorado River to fill Lake Mead behind Hoover Dam," continued Mr. Beard. "Constructing the dam was an historic blunder of monumental proportions and based on a false set of assumptions. It was the product of wheeling and dealing, and today we are stuck with a half-empty reservoir that evaporates nearly a million acre-feet of water into the atmosphere."

The executive summary of the draft EIS notes the adverse impacts the dam has on the downstream ecology, stating that the dam prevents sediments and nutrients from flowing through the Grand Canyon, lowers the temperature of the river water, and has "altered aquatic and terrestrial systems compared to those before Glen Canyon Dam."

Conversely, the summary notes, "(H)ydropower is cleaner than nonrenewable fuel resources, and if water releases are less constrained, hydropower can be more responsive to changes in load than many other forms of electrical generation. The Glen Canyon Powerplant is an important component of the electrical power system of the western United States and is the largest hydroelectric facility in the (Colorado River Storage Project)."

The shear size of the draft -- Executive Summary, eight chapters, and 14 appendices -- no doubt played a role in the decision for a 90-day public comment period, which runs out April 7.

At the National Parks Conservation Association, officials said it would take them time to digest the contents.

“NPCA has been working on this issue for years as a member of a multi-stakeholder working group. Our goal is to ensure that Grand Canyon National Park, one of the crown jewels of America’s National Park System, is protected," David Nimkin, the group's Southwest regional director, said in a prepared statement.

"While we acknowledge that it is impossible to replicate natural river system conditions under the constraints presented by Glen Canyon Dam, we anticipate that the preferred alternative identified in the draft LTEMP includes several strong measures to benefit the Colorado River system inside the Grand Canyon. We will be carefully reviewing details of the plan to develop our recommendations and responses throughout the public comment period.”