Getty/Robin Beck

A Native American tribe is winning its battle against a North Dakota pipeline project.

Since April, the Standing Rock Sioux Tribe has been fighting the construction of the Dakota Access oil pipeline on their reservation and across the Missouri River, which abuts their land. What is at stake, they say, is the destruction of sacred sites on nearby land taken from the tribe in the 1980s. Most worryingly, there is also the potential for contamination of the Missouri River, which is the main source of water for the reservation’s 8,000 residents. On Tuesday, a judge responded to the tribe’s request for a restraining order by handing down a temporary halt to parts of the project, and said he would rule on Friday on the tribe’s injunction to stop the project in its entirety until the disputes between the tribe and the U.S. Army Corps of Engineers are resolved.

The protest encampment outside the town of Cannon Ball has grown to include hundreds of people, many from other tribal nations, environmental coalitions, and Black Lives Matter. The largely peaceful protests came to a head over the weekend, when Dakota Access, the company in charge of the construction, began to dig up some of the sacred sites, and private security guards unleashed attack dogs and sprayed tear gas on protesters.

Tribal representatives stressed that their efforts weren’t just aimed at protecting the water for the reservation, but also the 17 million people who live downstream. As a member of the Pine Ridge Indian Reservation told The Washington Post, “It’s not going to be if it breaks, it’s going to be when it breaks.” Considering that more than half of the pipelines in the U.S. are more than 50 years old, and that pipeline ruptures occur regularly (most recently in a catastrophic spill in Louisiana), there is clearly a lot at stake for the Standing Rock Sioux.