The D-N-R may never be able to determine for certain how much of a manure spill in Dallas County made it into the river that supplies drinking water for towns including Des Moines. DNR Environmental specialist Bill Gibbons says the agency was first notified about 5:00 Tuesday morning.A worker arriving at the farm discovered and phoned the DNR reporting hotline, after waste had been released from a barn and run into an unnamed creek that drains into the river. Gibbon says a holding tank valve may have malfunctioned and sent stored manure back into a livestock barn, where it overflowed out across the ground. In all, 50-thousand gallons spilled but Gibbons can’t say how much went into the river.Some ran across the ground, down a hillside and was slowed and pooled by the ground and vegetation. Gibbons says the worker did the right thing by phoning the DNR’s manure-spill hotline right away, and the agency told people downriver who might be affected. The DNR will send a notice of violation to Carstens Farms, but hasn’t made a determination whether a fine will be levied, since the company was prompt about notifying officials and cooperating in the investigation. The reporting number for any manure spills or wastewater releases in the state is 515-281-8694.