It was with great disappointment that I read your editorial "Turning Nature On and Off" (Sept. 6). While I appreciate your concern for the environment of Grand Canyon and the effects of Glen Canyon Dam operations, the editorial contained several serious errors.
You indicate that present operation of Glen Canyon Dam disregards all considerations but maximizing hydroelectric power generation. This is not true. Present criteria for coordinated long-range operation of the Colorado River Reservoirs, established in the late 1960s, provides for appropriate consideration for all beneficial uses of the river, including in-stream flow values and recreation, consistent with "the law of the river." It must be understood that most of the multiple uses compete with each other and operating plans for the river are a balanced consideration of all uses.
The present blue ribbon trout fishery and recreational use of the Colorado River below the dam have developed as a result of the dam and 20 years of operations under these criteria.
Since 1982, the Bureau of Reclamation has been conducting the Glen Canyon Environmental Studies to determine the impacts associated with existing operational criteria and to determine if modification is warranted.