Residents of the town of Poplar on the Fort Peck Indian Reservation continue to deal with a massive groundwater contamination from oil and gas activity, and a new report released last week by the U.S. Geological Survey shows that the contamination is only spreading. The federal agency says the issue has led to polluted drinking water for more than 3,000 people.
The contamination was first discovered in the 1980s, when residents living near the East Poplar oilfield noticed their drinking water tasted especially salty and contained an odd, amber hue. Since those initial complaints, the USGS and the Fort Peck Office of Environmental Protection have worked to understand the cause of the contamination and its extent. Though it is now well established that the problem resulted from antiquated oil production practices nearly 60 years ago, experts have had considerably more trouble determining just how far the polluted water has spread.
The terrain surrounding Poplar includes a predictable mix of soft rolling hills and deep gullies, but the area is more complex below the surface. The USGS can only track the contaminated water by drilling small individual wells and sampling the water beneath, or by flying expensive electromagnetic detectors over the area via helicopter. The report released last week used a combination of the two methods to draw its conclusions, and found the contamination has increased from 12.1 square miles in 1997 to 17.9 square miles today.
The reason the contamination continues to spread can be linked to the location of the oilfields. The East Poplar oilfields connect to the Williston basin. "The water that is produced with oil and gas development in the Williston basin is extremely saline," USGS hydrologist Joanna Thamke says.
In fact, the water beneath the Williston basin is some of the most saline water in the nation. When oil is extracted from deep underground, it also brings water back to up the surface. The Williston basin water is saltier than seawater, so a little bit goes a long way to causing contamination issues. In this case, time will not heal the damage already done. The USGS data suggests the situation will only get worse over time.
"The implications show that in this area there are quite a few individual plumes that might have originally started out small, but with time the effects add up to a larger area," Thamke says.
The slow spreading of the contamination means that nothing in the groundwater's gravity-drawn path is safe. Nearly 20 years after the contamination was first discovered, it seeped into the city of Poplar's water supply. The problem went from affecting the drinking water of 100 residents to impacting more than 2,900.
In a rare stroke of good fortune during more than three decades of pollution, the Fort Peck Reservation Rural Water System project neared completion just as the contamination reached Poplar. The federally funded project pumped water from the Missouri River to a water treatment plant to be purified. Poplar was the first city to benefit from this project.
"Thank god for the water pipeline," says Deb Madison, manager of the Fort Peck Office of Environmental Protection, "because that means we have potable sources of water for drinking."
But there are still problems that cannot be fixed by a pipeline. According to Madison, the area's groundwater is so salty that any long-term development for irrigation or stalk water is inadvisable. On a reservation where the majority of the land is used for agriculture or to raise cattle, the lack of options presents a huge challenge.
The permanent damage caused by the contamination prompted the Fort Peck tribe to make sure nothing like it ever happens again. The tribe is in the process of establishing a set of strict stipulations that oil and gas developers are required to incorporate into their Application for Production Approval.
"[These stipulations] work to really make sure that where they say gas is going or water is going, it actually gets there, and stays there," Madison says.
The tribe's proactive response comes as welcome news to Thamke at the USGS. She says it's important for oil and gas developers both on the reservation and in other areas of the Williston basin to learn from the mess of the East Poplar oilfields.
"I think what's important to know is that today, we still have very saline water being produced with the oil and gas," Thamke says. "I think it's something that's important for managers to be aware of and development companies to be aware of, so they proceed carefully to develop one resource and minimize the effects to the others."