FRESNO — Ambitious plans to remodel lodging, move a road and expand campsites in Yosemite National Park are on hold until officials prepare a better plan to protect the Merced River, which runs through the heart of the park, a judge ruled.

Two conservation groups celebrated Friday’s ruling, which effectively halts about $60 million in construction projects for at least two years, as a major environmental victory.

Yosemite officials, still reeling from the decision, said it could have “huge negative impacts” on the park’s efforts to accommodate the 3 million visitors who travel there each year.

“The fact that now we can’t repave a road, with winter coming on, is just devastating,” said Scott Gediman, a park spokesman. “Sure you can argue about campgrounds or building the lodge, but what about when you’ve got paving on a road that’s literally falling apart?”

The order, issued in a U.S. District Court in Fresno, directs the park service to immediately stop nine projects included in the Yosemite Valley Plan, a grand scheme to develop the park’s amenities that has been the subject of a lengthy legal battle.

While the case likely will be appealed, legal scholars said it was not surprising that part of the park’s $442 million remodeling effort now figured in a lawsuit.

“Anything that’s done in a national parks system, particularly those that are beloved and heavily visited, is likely to be challenged by some group of stakeholders,” said Richard Frank, an environmental law professor at the University of California, Berkeley’s Boalt Hall School of Law. “We’re seeing more litigation of this kind than ever before.”

Under the Wild and Scenic River Act, the park is required to have a plan to regulate development near the banks of the Merced, whose tributaries course through many of the Valley’s cherished sites. A creek borne of the river, for instance, rushes over Yosemite Falls, the tallest waterfall in North America.

The river became central to debates over Yosemite’s future in 1997, when it wiped out campgrounds, lodging and parking in a flood. Environmental groups said the park’s plans to replace those features did not adequately protect the Merced, and filed suit.

By 2004, the case had made its way to the 9th U.S. Circuit Court of Appeal, which ordered officials to revise their management plan for the river.

But park officials have failed to write a management plan that adequately protects the river, U.S. District Judge Anthony Ishii ruled Friday.

The judge sided with the plaintiffs, who argued some of the construction projects lie directly in the Merced’s flood plains and as such, could harm the river’s “outstandingly remarkable values.”

“What the court is saying is, it’s in the public’s interest to stop the park from doing what it wants to do, immediately,” said Greg Adair, executive director of Friends of Yosemite Valley, which filed the suit along with Mariposans for Environmentally Responsible Growth.

“Yosemite is an ecological treasury of the Sierra Nevada and as we see the population growing and global changes happening, its resources become more and more precious,” Adair added.

Park officials now must devise a legally valid plan to protect the Merced River before going ahead with projects to upgrade the Valley’s sewer system, redevelop Yosemite Lodge and repave roads.

In Friday’s order, Ishii agreed with a previous ruling that park officials did not properly assess the impact of an increased number of visitors — an issue also raised by environmental groups.

“We need to put in place some kind measure to keep the Valley from being loved to death,” said Barbara Boyle, a spokeswoman for the Sierra Club in Sacramento. “The overall problem that we face in Yosemite is how to reduce the footprint of the development and commercialization in the park. How many people is just too much?”