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LINCOLN — The weekend spill of petroleum from a pair of underground pipelines in southeast Nebraska has been downgraded by more than half.
Pipeline operator Magellan Midstream Partners of Tulsa, Okla., initially estimated 6,000 barrels of gasoline and diesel fuel were released after the pipelines were struck Saturday by a bulldozer working on farmland near Nemaha. The company issued a revision Tuesday, saying the spill involved 2,834 barrels of gas, diesel and jet fuel.
The company calculated the more accurate quantity by analyzing volumetric metering and pressure loss data, said Bruce Heine, Magellan spokesman. The revised spill equates to 119,028 gallons, down from the estimate of 252,000 gallons.
The Nemaha spill ranks as the largest pipeline release in Nebraska since nearly 5,000 barrels spilled from the Platte Pipeline in 1996 near Lawrence, said Jim Bunstock, spokesman for the Nebraska Department of Environmental Quality.
A bulldozer operator ruptured the pipelines 2½ miles southwest of Nemaha on Saturday. Some of the spill made it to a nearby creek, a tributary of the Little Nemaha River.
By Monday afternoon the broken lines had been repaired and the flow of fuels resumed, Heine said. The pipelines transport gasoline, diesel and jet fuel from Texas to terminals in Omaha, Lincoln and Doniphan, Neb., among other locations.
Meanwhile, a cleanup crew of 65 company employees and private contractors remained on site, working to recover as much of the fuels as possible.
No one was injured in the incident and no evacuations were ordered. Nemaha, a village of 150 people, is about 90 miles south of Omaha.
In 1989, 6,300 barrels of petroleum products were spilled at Williams Pipeline in Omaha, Bunstock said.
Pipeline operators have reported 77 incidents in the state since 2001, for a combined spill total of 4,173 barrels, according to records kept by the federal Pipeline and Hazardous Materials Safety Administration.
Prior to Saturday's spill, there had been seven Nebraska pipeline incidents in 2011 for a total of 104 barrels spilled, the federal agency reported.
The pipelines were damaged when a bulldozer operator — whom the company described as a landowner — was tearing out trees with a “ripper,” Heine said. The plow-like piece of equipment is attached to the rear of a bulldozer and is used to break up hard soils or remove tree stumps.
The company detected the breaks at 11:19 a.m. Saturday when a staff member in a control room in Tulsa detected a pressure drop. The lines were shut down “promptly,” Heine said, although he declined to offer a detailed time line of how quickly the shut-off took place.
The company dispatched crews from Omaha, Des Moines, Kansas City and Tulsa to the site on Saturday. The state Department of Environmental Quality and the federal Environmental Protection Agency sent representatives to the site.
Initial efforts focused on vacuuming fuel from the soil and the creek, which is about one-third of a mile from the spill site. The unnamed stream is a tributary to the Jarvis Creek, which flows into the Little Nemaha River and eventually the Missouri River.
Crews installed four structures called underflow dams on the creek in an attempt to keep the fuel from flowing downstream.
An underflow dam draws water from the bottom of a stream through a tube and allows it to continue downstream. Because petroleum floats, the dam holds the fuels back so they can be removed, Bunstock said. Such structures are preferred over holding back the entire stream flow, which would cause the contaminated water to flood surrounding property.
The company also has built berms on the site to contain runoff from rain, which is forecast for Tuesday and Wednesday.
State officials have set up monitoring sites downstream from the spill to measure for contamination. They also will drill deep into the soil to determine how far the fuel has penetrated. Contaminated soil will have to be removed.
“There have been no dead fish reported,” Bunstock said Monday afternoon. “There's a lot of monitoring going on.”
The company spokesman declined to say how deeply the pipelines were buried. He indicated there had been no call to the digger's hotline, as required by state law before any underground work is done.
It's too early to say if state or federal officials might levy fines in the incident.
Contact the writer: 402-473-9587, joe.duggan@owh.com
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