CANON CITY, Colo. – Opponents of a plan by the artist Christo to hang nearly 6 miles of silvery fabric in sections over the Arkansas River say the project is still a danger to fish and visitors and they are considering an appeal after a federal judge refused to intervene.

Members of Rags Over the Arkansas River, also known as ROAR, filed the lawsuit, contending the project threatens bighorn sheep, public safety, traffic on U.S. 50 and businesses that depend on the scenic river to draw anglers, rafters and tourists.

A federal judge ruled Friday that there is no evidence federal officials failed to comply with environmental laws, as opponents said in their lawsuit.

“We have one lawsuit in state court still outstanding, but today we took a very significant and important step forward in realizing Over the River,” Christo told The Pueblo Chieftain.

Christo said the project could go ahead as soon as August 2018 if he wins the state court lawsuit.

A Colorado judge has already ruled the state acted properly while giving its approval to the project.

The opposition group claimed that the U.S. Bureau of Land Management violated federal law by failing to comply with the Federal Land Policy and Management Act and the National Environmental Policy Act. The judge disagreed, concluding that bureau did not violate the laws.

In a statement Saturday, members of ROAR said that although the court found the project technically complied with federal law, it did not dismiss concerns over the destructive nature of the project.

The project is expected to be displayed for two weeks in the month of August, when the river would be calm enough for rafters to peer up at the fabric as they float underneath and when drivers on U.S. 50 along the river could look down.

Christo and his late wife, Jeanne-Claude, began scouting for a location for the temporary installation in the 1990s. After visiting 89 rivers in seven states, they chose the Arkansas River between Salida and Canon City.