When a Kinder Morgan gasoline pipeline burst in southern New Mexico last December, more than 10,000 barrels of gas spilled into a drainage ditch. Cleanup efforts are still underway, and both ground and surface water are at risk.
After the spill, a cleanup crew recovered a little more than 6,000 barrels of gas. That means more than 4,000 barrels soaked into the soil.
“We know that the soil was obviously contaminated by the gas,” says Zach Libbin, an engineer with the Elephant Butte Irrigation District. “And the groundwater table isn’t very deep. So the groundwater was also impacted.”
The pipeline runs across EBID property and spilled into one of its ditches, known as the Anthony Drain. This limited the amount of soil that was damaged. The gas didn’t spread out across a wide distance; it was mostly contained in the drain. But it did soak downward, which is a real problem, because the drain is so close to the water table.
“Because the gas seeped all the way down to the groundwater table and sat on top of the groundwater table, we know that at least some of it has dissolved into the groundwater,” Libbin says. “How far and how much and how fast that’s moving is to be determined.”
Kinder Morgan is conducting tests to determine the extent of the damage, and working to clean up the area. Step one: remove the contaminated soil.
“In groundwater issues like this, the most important thing to do is to eliminate the source,” says Justin Ball with New Mexico’s Environment Department, which is overseeing the remediation process. “Basically, there will be an ongoing supply of contamination into the groundwater until you take care of the source.”
Hulking yellow backhoes remain at the site, digging up mounds of gasoline-soaked soil - which will ultimately go to a disposal site, most likely out of state.
Ball says there’s at least one challenge to fully excavating the site. A power line runs through it.
“They’ve been given a radius around the power poles that they’re not allowed to dig in order not to affect their integrity and therefore they won’t fall over and cause an accident,” says Balls.
Kinder Morgan will have to come up with some other way to remediate the soil in that radius.
Once the contaminated soil is gone, it’s time for steps two and three: reconstructing the drainage ditch, and cleaning the contaminated groundwater.
"The groundwater component will be the hardest and the longest part to clean up compared to just physically removing the contaminated soil and transporting that away,” says Zach Libbin.
There are several possible ways to clean contaminated groundwater, from pumping it out of the ground and treating it on the surface, to using microbes that eat up contaminants.
Libbin says this step is incredibly crucial, not just to stop just to stop contaminated groundwater from spreading to nearby residential and irrigation wells, but to prevent it from becoming surface water “that would then flow down the drain all the way to the river.”
The Anthony Drain is currently dry. But if the water table gets high enough, the contaminated groundwater could rise to the surface and flow out to the Rio Grande.
The odds of that happening are relatively low, at least for now. New Mexico is in an extended drought and farmers continue to pump groundwater. But Libbin says the remediation process can take a long time; and if we get a good snowpack during that time, the river could be at risk.
“While we certainly hope for a great surface water supply this year and into the future, not having a great surface water supply will keep that groundwater table from becoming a surface water contamination issue,” Libbin says.
In the meantime, Libbin says he’s watching for signs of contaminants in residential and irrigation wells. So far, tests haven’t shown any. But that could change, especially once farmers turn on their wells and start pumping in the spring, which could cause the contaminated water to spread.
EBID is reviewing the special use permits it’s granted Kinder Morgan, to run gas lines across its property.
“As with any pipeline, there’s more than zero risk” to EBID and the ground and surface water supplies, Libbin says. “But we need to make sure those risks are minimized and those pipelines are as safe as they can be and are meeting all requirements. Certainly this spill gives us a reason and concern to evaluate those permits and see if any changes need to be made.”
