Assessment Comments
Assessment is based on results of fish kill investigations in June 2006 and August 2007.
Basis for Assessment
SUMMARY: The Class A1 (primary contact recreation) uses remain "not assessed" due to the lack of water quality information upon which to base an assessment. The Class B(WW1) aquatic life uses of this waterbody remain assessed (evaluated) as “partially supported” due to a fish kill in June 2006 and a fish kill in August 2007. Both kills were attributed to natural causes. This impairment is appropriate for Category 3b of Iowa’s Integrated Report. Fish consumption uses remain "not assessed" due to lack of fish contaminant monitoring and data for this lake upon which to base an assessment. Lake Panorama is a privately-owned lake and is thus not part of IDNR’s statewide ambient lake water quality monitoring program.
EXPLANATION: The first kill occurred on or before June 19, 2006. The kill was attributed to natural causes (fish disease/parasite/stress). Two thousand fish were estimated to be killed (all yellow bass); no estimate of the value of the fish killed was provided. The IDNR Fisheries Bureau suggested that the kill was likely caused by a disease of yellow bass.
The second fish kill occurred on or before August 21, 2007. The kill was attributed to "natural" causes. The likely cause was low dissolved oxygen following an algae die-off. Three hundred crappie were estimated to be killed. No estimate of the value of these fish was made.
This is the same assessment as that developed for the 2008 and 2010 assessment/listing cycles. The continuance of the IR Category 3b listing is based on IDNR's assessment methodology that states the following: 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 was not identified during the IDNR investigation, or if the kill was attributed to non-pollutant causes (e.g., winterkill), the assessment type will be considered “evaluated” and will be placed in IR subcategories 2b or 3b and will be added to the state list of waters in need of further investigation. Thus, this assessment segment will remain in Category 3b of Iowa’s Integrated Report.
The fish consumption uses remain "not assessed" due to lack of fish contaminant data upon which to base an assessment.
