Roberts Creek IA 01-TRK-1931

A fish kill occurred in this stream segment on or before August 1, 2005 and was caused by a release of hog manure from an over-full storage pit. According to the DNR investigation, an outdoor storage pit lacked sufficient capacity to handle the amount of manure delivered to it from an indoor storage pit; thus, an overflow occurred. Approximately 2.25 miles of Roberts Creek were affected by the resulting kill. The kill began in an unnamed tributary to Roberts Creek in Section 8 of T95N, R6W, Clayton County, and proceeded downstream through Section 9, 15, and 15 of T95N, R6W. An estimated 8,000 fish were killed. Based on DNR records, the value of the fish killed was estimated at $4,893. Other than a notation that the kill affected “mostly non-game species", no detailed information on species killed is available. The party responsible for the kill was identified. DNR sought and received restitution for the value of the fish killed and the costs incurred by DNR during investigation of the kill.

According to the DNR assessment/listing methodology, the occurrence of a single pollutant-caused fish kill, or a fish kill of unknown origin, on a waterbody or waterbody reach indicates a severe stress to the aquatic community and suggests that the aquatic life uses should be assessed as “impaired”. If a cause of the kill is identified, and the cause is either known, or suspected, to be a “pollutant”, the assessment type is considered “monitored” and the affected waterbody is a candidate for Section 303(d) listing. If, however, a consent order has been issued to the party responsible for the kill and monetary restitution has been sought for the fish killed, the affected waterbody will be placed in IR Category 4d (impaired but TMDL not required). DNR feels that (1) TMDLs should not be required for kills caused by a one-time illegal or unauthorized release of manure or other toxic substance where enforcement actions were taken and (2) enforcement action is more appropriate, efficient, and effective for addressing a spill-related impairment than is the TMDL process. DNR considers IR 4d fish kill waters with no subsequent kills in at least the five years subsequent to the kill as appropriate for movement to IR categories 2b or 3b (i.e., Iowa’s list of waters in need of further investigation). Thus, this fish kill impairment was moved to IR Category 3b for the 2012 Integrated Report and remains in IR Category 3b.