Is the fox guarding the chicken coop at the Department of the Interior? According to most people interviewed on ''James Watt's Environment: Promised Land'' (PBS, Wednesday, 9-10 p.m., check local listings - schedules vary greatly), Secretary of the Interior James Watt is the fox, and the chicken coop is the American wilderness. And, according to just about every environmental organization, Secretary Watt is bent on ''running a bulldozer through the wilderness.''
Except for a few kind words from oil and timber spokesmen and his own Mountain States Legal Foundation, Mr. Watt, who declined to be interviewed for this documentary, must speak for himself in old film clips. The evidence is marshaled by producer John Angier and Graham Chedd (both of ''Nova'' fame) with devastating, if slightly one-sided, effect.
The startling documentary seems bent from the very start on proving its bold claims that Secretary Watt is in favor of allowing timber interests to deplete US forests, coal interests to strip mine US national parks, oil interests to exploit US public lands.
Secretary Watt and the few admirers who are allowed to speak in this film defend their position that wildlife preservation and partial industrialization of the wilderness are not incompatible. Mr. Watt's defenders insist that he is being made a scapegoat for environmentalists wishing to make an early stand for their beliefs.
Since the secretary of interior refused to contribute to the film, viewers will have to decide for themselves if the case against him consists of self-serving statements by elitist environmentalists, or, instead, desperately sincere statements by environmentalists who honestly believe that future generations may be deprived of the natural wonders of the earth because of short-sighted government policies now.
In any event, it is filled with horrific views of denuded lands in Appalachia , bare forest floors in the Northwest, despoiled wilderness areas in Montana and Wyoming, the current threat of invasion of Jackson Hole. Some of the beautifully photographed scenery will have viewers gasping for breath at the wonder of it all - perhaps even impressed enough to join the battle against President Reagan's apparently industry-oriented secretary of the interior. Or at least to delve further into what is really happening to America's wilderness.
Somewhat overwhelmed in this perhaps understandably partisan film are the arguments of Watts and his people that they do not wish to foul the wilderness, only to accept the reality of the need for a small portion of the enormous acreage which is now public land to be industrialized in the national interest. The environmentalists interpret any attempt to change past policy as further evidence of the self-serving greed of industrial America.
What the film makes clear is that the difference between private enterprise and private greed, between selfish environmental elitism and the public good, is often difficult to distinguish.
If your family has been postponing plans to make that long talked-about visit to Yosemite and Yellowstone, ''James Watt's Environment'' may make you feel you should take out those old roadmaps and schedule the journey to the national parks while they are still comparatively unspoiled.