A man stands next to homemade shields in Sacred Stone camp, one of the few remaining camps protesting the Dakota Access Pipeline in Cannon Ball, North Dakota, U.S., February 24, 2017. REUTERS/Stephen Yang

WASHINGTON (Reuters) - A U.S. judge said on Tuesday he hopes to decide by about March 7 on a request by Native American tribes for the Army Corps of Engineers to withdraw an easement on religious grounds for the final link of the Dakota Access Pipeline.

At a hearing Judge James Boasberg of the U.S. Court in Washington, D.C., said he hoped to provide a written ruling by that time on the injunction requested by the Standing Rock Sioux and Cheyenne River Sioux tribes regarding the final section of the line to go under a lake in North Dakota.

Boasberg said if Energy Transfer Partners, the company building the $3.8 billion line, expects the project will be completed and oil will flow before March 7, that the company must give him 48 hours notice so he can release his ruling.

The tribes, who have rights to water access in the area, say that the oil pipeline would spiritually degrade river and lake water and harm religious practices even if it does not spill.

Their legal options to stop the pipeline are dwindling.

Earlier this month, Boasberg denied a request by the tribes for a temporary restraining order to halt construction of the project.

Boasberg on Tuesday questioned how the water could be harmed since the pipeline is being built under the Lake Oahe and oil would not likely touch the water in the event of a spill.

Nicole Ducheneaux, a lawyer for the tribes, said at the hearing that the pipeline would spiritually degrade the water on the Missouri River because of its presence and that would prevent tribes from carrying out ceremonies because other nearby water sources had been contaminated from decades of mining.