MILFORD -- The DNR and NuStar Energy L.P. have located the source of a petroleum leak running into a stream south of Milford in Dickinson County.
The leak was reported after a farmer who was watering trees Thursday afternoon discovered a sheen and a strong petroleum odor on an unnamed tributary of the Little Sioux River.
The DNR and NuStar traced the diesel fuel leak to a tile line draining a crop field belonging to Todd Gonnerman Thursday night. A team from NuStar worked late last night skimming diesel off the creek and pond.
They also excavated parts of the tile line and found a small section of pipe with a corroded area and a crack in it. NuStar officials said the crack took a long time to develop and think the pipe was nicked last fall during tiling installation.
"If so, this is a good example of why it's so important to call Iowa One Call," said Jennifer Christian, a DNR environmental specialist at the scene.
Christian says clean up of the site will take a while and involve excavating about 200 yards of tile line and hauling contaminated soil to a landfill, possibly flushing or replacing the tile line, and flushing and cleaning up two miles of stream and a farm pond.
The DNR will continue to monitor the spill and its clean up, and will consider appropriate enforcement action.
Iowa One Call is a free service required for all excavations. Call 800-292-8989 or 811 at least 48 hours prior to excavating.
Christian said because they found only a few dead fish at the farm pond, the fuel leak is probably not the cause of death. Recent high temperatures or possibly a drop in oxygen levels are more likely causes.