Iowa Department of Natural Resources
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May 14, 2009
For immediate release
1. Rock Valley manure release leads to fish kill
ROCK VALLEY MANURE RELEASE LEADS TO FISH KILL
MEDIA CONTACT: Ken Hessenius or Jeff Prier, Spencer field office, at (712) 262-4177 or [log in to unmask] or [log in to unmask]
ROCK VALLEY — Fish are dying in a privately owned pond following a manure release from a Rock Valley dairy in Sioux County.
The DNR began investigating the manure release from Meadowvale Dairy, also known locally as Ysselstein Dairy, on Tuesday evening. However, DNR staff did not observe dying fish until Wednesday afternoon. They are conducting a fish count Thursday morning.
On Wednesday, manure stretched along five miles of an unnamed stream that flows in and out of Solberg Pond and eventually into the Big Sioux River. While it is unknown how much manure the dairy released or how much reached the stream, a pumping company hired by the dairy estimates it pumped up about 300,000 gallons of manure from the field on Tuesday.
Field tests of water samples showed ammonia levels of 30 parts per million (ppm) on Tuesday. Wednesday, dissolved oxygen levels dropped to zero. Ammonia levels higher than 5 to 10 ppm are generally toxic to fish and other aquatic life. Dissolved oxygen levels measure the amount of oxygen fish can pull from the water.
Monday evening, an employee of Green Earth Nutrients turned on a center-pivot irrigator to move through a field and spread manure from the dairy. The employee returned Tuesday morning to find the equipment stuck in the freshly tilled field, located about two miles northwest of the dairy. Once stuck, the equipment continued to spray manure in one spot, allowing the manure to pool and flow over land into the stream.
Green Earth Nutrients is owned by Sjerp Ysselstein. A different landowner owns Solberg Pond.
The dairy reported the spill late Tuesday afternoon, but DNR staff was already en route to investigate, responding to a call from a concerned citizen about the stream.
The DNR is continuing its investigation, including looking at additional runoff issues at the dairy, and will consider possible enforcement action.
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