Crews are cleaning up a manure spill that occurred in Jefferson County Thursday. An estimated 3,000 gallons of manure spilled into an unnamed tributary of Cedar Creek when a Porter Farms tanker went off the road on 25th Street, three miles south of Fairfield. The creek was dammed and the contaminated water was pumped onto land owned by Porter Farms. According to the Iowa Department of Natural Resources, it will be difficult to determine how many fish were killed by the spill since all the water from the dammed creek was land applied. Cedar Creek was unaffected by the spill. The remediation work is expected to be completed today.