Case study: Environmental problems from N. Dakota evaporation pits linger
BISMARCK — North Dakota long ago phased out the practice of storing saltwater from oil production in evaporation ponds, but the environmental effects still linger today and likely will for decades to come without remediation, according to a case study in Bottineau County.
The study, published in 1988 and led by Ed Murphy of the North Dakota Geological Survey, focused on a site near Maxbass that had two brine-holding ponds from 1959 through the late 1970s, when they were backfilled and leveled.
The site, which had been converted from an oil production well to a saltwater disposal well in 1978, was chosen because of obvious salt damage to crops and a shelterbelt next to the pond site, and because it was representative of many pond sites in North Dakota, the study said.
When oil production began in North Dakota in 1951, most saltwater at drilling sites was disposed of in injection wells and evaporation ponds. The state produced about 890 billion barrels of oil from 1951 to 1986 and more than 955 million barrels of saltwater during that time period.
The North Dakota Geological Survey didn’t require permits for saltwater handling facilities until 1969, and over the next dozen years it issued 206 permits for evaporation ponds.
The number of ponds that operated before 1969 wasn’t known, according to the study.
After the last of the brine ponds was phased out in North Dakota in 1982, environmental concerns switched to the spread of brine from abandoned ponds to soil and groundwater.
In the Bottineau County case study, Murphy and the other researchers concluded that brine had leached downward 70 feet below the surface and, even more concerning, outwardly in a 500-foot radius around the holding ponds, causing soil sterility, stunting crops and killing trees on the land, which by that time was owned by North Dakota State University.
“If no remedial action is taken, this site will continue to generate highly saline leachate for tens and possibly hundreds of years,” the study stated.
Murphy, now the state geologist, said the Geological Survey didn’t do a follow-up study on the site.
The study’s authors hoped it would encourage oil companies to voluntarily reclaim abandoned brine ponds in North Dakota, writing that it was in their best interests because of the growing tendency of juries to award huge sums of money to landowners for damages resulting from improperly reclaimed brine ponds in Oklahoma and other oil-producing states.