Fish Kill Event - East Branch Blue Creek

About 1:20 Sunday afternoon I was paged concerning a fish kill at Walker. I contacted the caller, Doug Rawson, who said that previous fish kills had occurred. I responded to the site with Sue Miller who had been on previous fish kills in that area. We first checked the bridge crossing of Blue Creek south of the wastewater treatment plant. Lots of live fish. We checked the wastewater treatment plant's outlet. It was dry. We went into town and checked the two bridges that cross the creek. We noted one minnow at the north crossing and about 10-15 minnows at the south crossing. We checked for nitrogen and dissolved oxygen. Both showed good water quality. We went to an outlet that receives water from FJ Krob feed mill. It had been the site of previous fish kills. A high level of nitrogen was noted. Dissolved oxygen was fairly high. However, a school of minnows was noted along the opposite bank of the stream. A sample taken about five feet upstream did not show any sign of nitrogen. A sample taken 40 feet downstream showed nitrogen in the water.

We went to FJ Krob feed mill. We dropped Nessler's reagent on several suspect areas to determine if there had been any run off of ammoniated water. None was found. We checked a new tile line that had water in it. No result. The ground around it was clear also. The only sites where nitrogen was located was in the urea overflow area (to be expected - none was found surrounding that area) and in stagnant water in the ditch to the south of the new tile line area.

We talked to the gentleman who installed the new tile. He said that the intakes we noted were the only ones that went to the outlet where we found the nitrogen. Assumptions were made that rains the previous week had flushed out a low spot in the line that was holding residual contaminated water.

Sue Miller and I took a sample of the water coming out of the storm water outlet . I then walked down the creek from that outlet and found contaminated water about 100 feet from the outlet, but did not find any more "hot" areas after that. I went to the next outlet. No contamination was noted at that site.

Press Release

DNR investigators found about 15 dead minnows in Blue Creek on the south side of the town. They also found many live fish and good water quality in most areas of the creek. After on-site inspections and water tests at storm water outfalls, industrial sites and city area, the DNR found elevated ammonia levels at one of the storm water outlets. The DNR could not determine if the ammonia was the source of the fish kill. As a preventative measure, the DNR required an industrial site drained by the storm water outlet to flush and pump out any contaminated water still in the storm water pipe. The DNR ruled out runoff from the city’s wastewater treatment plant as a pollutant source. Investigators speculated that rainfall may have washed some pollutants into the stream, but they were unable to determine the precise source of the fish kill.