Three briefs in support of the NSAA suit have been filed, according to NSAA director of public policy Geraldine Link. They include separate briefs from the Colorado Petroleum Association and the Colorado Oil and Gas Association, and a group of water districts including the Colorado River Water Conservation District, Eagle River Water and Sanitation District, Ute Water Conservancy District, the Eagle Park Reservoir Company and the Clinton Ditch and Reservoir Company.

The broad support bolsters NSAA’s claim that the rule change would affect more than just ski areas.

"If the Forest Service is allowed to extract these concessions from the ski industry, then potentially the federal government will seek to demand the same or similar constraints from municipal and other water users as most of the headwaters and water sources in the western states arise on federal lands," the water districts' amicus brief states.

The NSAA alleged in its original suit that the Forest Service rules change amounted to an illegal takings, that the Service violated its own rules by making the changes without a public process, and that the permit language violates Colorado water law.

A ruling on the lawsuit could come in late August or early September.