Coal Creek IA 03-NSK-2018

Assessment Comments

Assessment is based on results of an IDNR investigation of a fish kill in September 2003 and on results of IDNR fish kill follow-up monitoring in September 2011.

Basis for Assessment

[NOTE: Prior to the 2008 Section 305(b) cycle, this stream segment was classified only for general uses.   Due to changes in Iowa’s surface water classification that were approved by U.S.   EPA in February 2008 (see http://www.iowadnr.com/water/standards/files/06mar_swc.pdf), this segment is now presumptively designated for Class A1 (primary contact recreation) uses and for Class B(WW1) aquatic life uses.   According to the Iowa Water Quality Standards, all perennial rivers and streams and all intermittent streams with perennial pools that are not specifically listed in the Iowa surface water classification are designated as Class A1 and Class B(WW1) waters.   Thus, for the current assessment, perennial flow is presumed, and the available water quality monitoring data will be compared to the applicable Class A1 and Class B(WW1) water quality criteria.]

SUMMARY:  The presumptive Class A1 (primary contact recreation) uses remain "not assessed" (IR 3a) due to the lack of information upon which to base an assessment.   The assessment of the presumptive Class B(WW1) aquatic life uses is changed from “partially supporting” (IR Category 5b) due to a September 2003 fish kill to “not assessed” (IR 3a).   This change is based on results of fish kill follow-up monitoring conducted by IDNR staff in 2011.   This change resulted in a de-listing of the biological (fish kill) impairment for the 2012 IR cycle.  

EXPLANATION:  This kill occurred on or before September 15, 2003; the kill was attributed to animal waste from an open feedlot.   Although comments from the investigation suggest than a number of fish were killed, the official estimate was one fish killed.   The location point for the kill is Section 4 of T76N, R13W, Keokuk County.   No estimate of stream length affected by the stream was provided; the party responsible for the kill was not identified.   According to the IDNR investigation, a citizen reported seeing some dead fish in Coal Creek; he said the creek had an odor and was discolored.   Ammonia levels along the creek were over 3.0 ppm (i.e., greater than the limit of the Hach test kit).   The creek water had a brown tint but suspended solids content didn't appear excessive.   Odor wasn't particularly noticeable.   A large beef lot appeared to be a source of the ammonia.   Water discharging from two tile lines tested above 3 ppm ammonia.   A well used to water the cattle in the feedlot was tested and it too showed significant ammonia contamination.  

According to IDNR’s 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 during the most recent assessment period 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.   Fish kills attributed to a pollutant, but where a source of the pollutant was not identified and/or where enforcement actions were not taken against the responsible party, will be placed into Integrated Report subcategory 5b.   The intent of placing these waterbodies into Category 5 is not to necessarily require a TMDL but to keep the impairment highlighted due to the potential for similar future kills from the unaddressed causes and/or sources.  

This stream segment’s fish community was sampled on September 2, 2011 as part of the IDNR Watershed Improvement and Water Monitoring sections’ fishkill follow up monitoring program.   Sampling methods described in IDNR’s fish kill follow-up protocol (Attachment 5 of Iowa’s 2012 assessment/listing methodology) were followed.   Approximately 800 feet of stream were sampled using a single pass with two backpack electro fishing units.   Results of this sampling show that this stream supports approximately 2,886 fish per mile compared to the Level IV ecoregion 47f average of approximately 1,399 fish per mile; 78% of the expected fish taxa for this ecoregion were sampled.   For detailed results of this sampling, see http://test.iowadnr.gov/bionet/Fish.aspx/Session/1275.   The results from this follow-up sampling and comparison of these results to ecoregion averages suggest that the fish community of this stream segment is similar to or better than non-fishkill impacted streams.   Although the results of the fishkill follow-up sampling lack the scientific rigor to determine whether the designated aquatic life uses are “fully supported,” the results do indicate that the stream has recovered from September 2003 fish kill event.   Thus, this stream segment is being moved from impairment Category 5b of Iowa’s Integrated Report to Category 3a (designated use not assessed).