By granting approval for major improvements at Solitude Ski Resort, the U.S. Forest Service this week said, in effect, that the changes will not damage Big Cottonwood Canyon.

The Solitude plan, only the first phase of more development envisioned by the ski resort in the future, provides for building new lifts and relocating others, and building new facilities at the base of the ski area. The changes will raise the resort's capacity from the present 3,400 to 4,600 skiers.The Forest Service action followed earlier approval by the Salt Lake County Planning Commission and the Salt Lake County Commission and is the final hurdle. Work on the project may begin in 15 days.

Opponents have argued that the Solitude improvements would increase congestion in the canyon and vowed to continue to wage a battle against subsequent phases of the project. Those further plans include a construction of sewer line and overnight lodging units.

The Forest Service approval also was criticized for being granted before Salt Lake County has finished its canyon master plan - the same criticism directed at county planners and commissioners earlier.

But it should not be forgotten that the Forest Service has its own master plan - one approved back in 1985 - and the Solitude project meets the limitation of that plan.

It would hardly be expected that the county's master plan would be more stringent than the U.S. Forest Service version. In fact, the Forest Service gained some concessions, including removal of Silver Fork for consideration for ski development, and reducing the amount of Forest Service land under permit to Solitude by 20 acres.

The canyons certainly are an irreplaceable resource - as watershed and for summer camping, as well as for skiing. But that does not mean that existing ski resorts should be banned from developing and improving their facilities, at least within carefully defined limits, such as the Forest Service master plan.

As the popularity of skiing in the nearby canyons grows - an economic plus for Utah - the pressure on the canyons undoubtedly will increase. Clearly, the canyon roads can't be allowed to become a mini-version of rush-hour I-15. There may come a time when private cars can no longer be allowed at ski resorts and only buses will be permitetd in the canyons.

Meanwhile, the new improvements authorized at Solitude seem reasonable and responsible.