Twenty years after artist Christo and his late wife first announced plans to drape the Arkansas River in Colorado with 5.9 miles of fabric, the project — which was finally approved by federal regulators in November — has hit one more snag: a lawsuit from an environmental group that has long opposed it.

The group, Rags Over the Arkansas River (ROAR), filed a lawsuit last week to block Christo's "Over the River" project, alleging the Bureau of Land Management (BLM), which approved the project, violated federal law in the process.

The suit was filed with the assistance of a University of Denver professor and two law students. "We are planning to vanquish the giant with the help of these great lawyers from the University of Denver," spokesperson Joan Anzelmo told the press on Feb. 1.

According to the New York Times, the lawsuit accuses the BLM of not properly addressing the project's impact on wildlife, including bighorn sheep, and of inappropriately classifying "Over the River" as a "recreational activity."

Christo's lawyer, meanwhile, told MSNBC that the art project "will withstand legal scrutiny."

But Michael Harris, head of the University of Denver's environmental law clinic, says the project's environmental impact must be taken into account. "For two years they're going to be in this canyon land, drilling holes, 9,100 holes, sometimes 30 feet deep to place anchors to hold all this in place," he said during a press conference outside the Denver federal courthouse.

Meanwhile, hundreds of Colorado locals have been filing into town halls, where construction permits for "Over the River" are being discussed prior to their approval. "God's natural beauty cannot be enhanced," Cañon City resident Marie Vernarsky told Fremont County commissioners on Wednesday, according to the Denver Post.

Even with the opposition, Christo told the Cañon City Daily Record he feels the Freemont County public meeting was "very polite, very civilized." He says he feels both stress and relief that his long-planned art installation is nearing its execution.

The "Over the River" art installation is scheduled for two weeks beginning in August 2014. Construction prior to the opening will last more than a year.

Environmentalists have long opposed "Over the River," arguing that the potential harm it would pose to area wildlife significantly outweighs the artistic benefits. But it has been strongly supported by government officials, who believe it could generate $120 million in tourism and construction revenues for economically depressed Colorado.

While discussions continue and the lawsuit moves forward, Christo is on his way to Abu Dhabi for another art project called "The Mastaba," which he has been planning since 1977. "It's a structure of 410,000 oil barrels," he told the Daily Record. "It is bigger than the pyramid of Cheops and Giza. Five-hundred feet tall, 1,000 feet by 750 feet of 410,000 oil barrels of marvelous colors, brilliant colors in the oasis about 120 miles from city of Abu Dhabi."

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Lawsuit takes aim at Christo's 'Over the River' project
Twenty years after artist Christo and his late wife announced plans to drape the Arkansas River in Colorado with 5.9 miles of fabric, the project has hit one mo