Iowa DNR investigating petroleum spill into West Nishnabotna River

The Iowa Department of Natural Resources is investigating an oil spill that entered the West Nishnabotna River from a truck stop near Avoca in western Iowa.

The spill follows a complaint of discharged petroleum at the same Eagles Landing Flying J Truckstop from this spring that the DNR was still investigating and working to help clean up when Tuesday’s spill was observed.

Alison Manz, an environmental specialist senior with the DNR, said it’s unknown how much petroleum entered the river, though she believed the spill was caught “right at the very beginning” of the plume.

Absorbent booms and other clean-up tools were placed immediately downstream in an effort to contain the petroleum from spreading and, as of Tuesday, no dead fish had been observed in the river.

Several months ago, when the department investigated the previous complaint regarding petroleum contamination at the same site just north of Avoca off Interstate 80, the staff found a “bigger issue” when they realized petroleum was being discharged into a stormwater retention basin.

Manz said the retention basin has been plugged and is “completely contained,” but clean-up for the roadside ditch and culverts connected to the retention basin has been an ongoing process.

“We don’t know how long that basin has been draining into the roadside ditch,” Manz said.

Recent heavy rains impacted the clean-up process of the ditches and caused an unknown amount of petroleum to flow into the West Nishnabotna River.

“I don’t know if we’re ever going to know what the quantity that went to the river is because all the residual that’s in the soil and in the culverts … we’re never going to know quantity,” Manz said.

She said the DNR had “no idea” how long the retention basin had been contaminated with petroleum discharges and draining into the ditch before the spring complaint brought it to the department’s attention.

A news release from the DNR said Eagles Landing had been cooperating with the clean-up activities, which Manz said would be extensive. Before the crews can clean and drain the plugged retention basin, they must excavate the roadside ditch and clean the culverts.

The department must also find the source of the leak.

“We know that it’s coming from Eagles Landing, but we don’t know where,” Manz said.

In 2011, the same facility had a leaking underground storage tank, but it received a “no action required” classification by the department following site assessments and cleanup.

Jessica Montana, supervisor for the DNR’s field office in Atlantic, said the facility had to have monthly monitoring reports conducted by a certified groundwater professional submitted to DNR.

Montana said the facility was in compliance and was “spot on” with submitting the reports.

The spring complaint and subsequent spill into the West Nishnabotna, however, means the DNR must investigate whether this petroleum is coming from a new leak or from the previously identified leaking underground storage tank.

“We’re still investigating what was released, and where, and why, and we’re still determining the source,” Montana said.

The DNR has advised the public to avoid the contaminated area on the river.

This article originally appeared in the Iowa Capital Dispatch.