Lake Petocka (formerly Lake Patoka) IA 03-SSK-1918

Data Sources:

Class BLW - Fish kill Assessment:

This fish kill occurred on or before April 14, 2005 and was attributed to “unknown/natural” causes. DNR field staff investigated this kill. An estimated 80 fish were killed including largemouth bass (25), crappies (25), bluegill (20), and catfish (10). No estimate of the value of the fish killed was provided. According to staff from the city of Bondurant, an additional kill at this lake had occurred recently due to the discharge of city (drinking) water to the lake after a company had tested a tank for leaks. Chlorine present in city water is believed to have caused this kill. Some dead fish from this previous kill were still evident at the time of the April 14th kill. During the DNR investigation, the water was clear and live fish were observed. Dead fish in various states of decomposition were present on the downwind side of the lake (north and east). A water sample collected from what appeared to be a field tile entering the lake from the west was analyzed by UHL (now SHL) for common Iowa agricultural chemicals and other water quality parameters. The results of these analyses did not suggest any causes of the kill.

According to DNR’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 indicates a severe stress to the aquatic community and suggests that the aquatic life use 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. For previous assessment/listing cycles, DNR had considered fish kill-impaired (IR 5b) waters with no subsequent kills in the three year subsequent to the kill as appropriate for de-listing and for movement to IR categories 2b or 3b (i.e., Iowa’s list of waters in need of further investigation). Due, however, to EPA uncertainty regarding the full recovery of the aquatic life following the kill, any existing fish kill (5b) impairment will remain in IR Category 5b until more recent monitoring has shown full recovery of the aquatic communities affected by the kill. Thus, this assessment segment will remain in Category 5b of the current Integrated Report.

Details about the 2005 fish kill can be found here: http://programs.iowadnr.gov/fishkill/Events/636

Class HH - Fish Tissue Sampling: