Assessment Comments
Assessment is based on: 1) results of the statewide survey of Iowa lakes conducted from 2009 through 2012 by Iowa State University (ISU), (2) results of the statewide ambient lake monitoring program conducted in 2008 by University Hygienic Laboratory (UHL), (3) information from the IDNR Fisheries Bureau, and (4) results of a fish kill investigation in May 2007.
Basis for Assessment
SUMMARY: The Class A1 (primary contact recreation) uses are assessed (monitored) as “not supported” due to poor water transparency and algal blooms that violate the state’s narrative criteria protecting against aesthetically objectionable conditions. The Class B(LW) (aquatic life) uses are assessed (evaluated) as “not supported" based on the results of a fish kill investigation in May 2007 and information from the IDNR Fisheries Bureau. Fish consumption uses are "not assessed" due to a lack of recent information upon which to base an assessment. Sources of data for this assessment include (1) results of the statewide survey of Iowa lakes conducted from 2009 through 2012 by Iowa State University (ISU), (2) results of the statewide ambient lake monitoring program conducted in 2008 by University Hygienic Laboratory (UHL), (3) information from the IDNR Fisheries Bureau, and (4) results ofs fish kill investigations in May 2007 and March 2011.
Note: A TMDL for siltation and nutrients at Badger Creek Lake was prepared by IDNR and approved by EPA in 2003. Because all Section 303(d) impairments identified for the 2014 assessment/listing cycle (algal growth [inlcuding nuisance growth of cyanobacteria]) are addressed by the TMDL, this waterbody remains in IR Category 4a (TMDL approved).
EXPLANATION: For the 2014 reporting cycle, the Class A1 (primary contact recreation) uses for Badger Creek Lake are assessed as “partially supported” based on results from the ISU statewide survey of lakes and the UHL ambient lake monitoring program. Using the median values from these surveys from 2008 through 2012 (approximately 15 samples), Carlson’s (1977) trophic state indices for Secchi depth, chlorophyll a, and total phosphorus were 67, 70, and 75 respectively for Badger Creek Lake. According to Carlson (1977) the Secchi depth value place Badger Creek Lake in between the eutrophic and hypereutrophic categories and the total phosphorus and chlorophyll a values places Badger Creek Lake in the hypereutrophic category. These values suggest very high levels of chlorophyll a and suspended algae in the water, poor water transparency, and very high levels of phosphorus in the water column.
The levels of inorganic suspended solids at this lake were high and suggest that high levels of non-algal turbidity may contribute to the poor water clarity at this lake. The median level of inorganic suspended solids in Badger Creek Lake (6.0 mg/L)and ranked 88th of the 134 lakes sampled by ISU and UHL.
Data from the 2008-2012 ISU and UHL surveys suggest a large population of cyanobacteria exists at Badger Creek Lake, which contributes to the impairment at this lake. These data show that cyanobacteria comprised 88% of the phytoplankton wet mass at this lake. The median cyanobacteria wet mass (29.1 mg/L) and ranked 96th of the 134 lakes sampled.
The Class B(LW) (aquatic life) uses for Badger Creek Lake are assessed (evaluated) as “not supporting” based on information from the IDNR Fisheries Bureau, and results of a fish kill investigation. Information from the IDNR Fisheries Bureau suggests that algal blooms and water clarity remain problems at this lake that affect the both the quality of the fish population and the likelihood of anglers using the lake. In addition, sediment resuspension, a lack of aquatic vegetation, and shoreline erosion are also problems at this lake.
Fish kills that occurred in this lake on or before May 17, 2007 and March 31, 2011 also suggests "impairment" of the Class B(LW) uses. The 2007 kill was identified as a natural kill related to spawning stress. Monitoring of the lake showed that the pH was high (9.2) and there was a large amount of brown algae in the lake. The total number of fish killed was estimated to be 1000. This is the same assessment as that developed for the 2010 and 2012 assessment/listing cycles. The 2011 kill was identified as a natural kill and related to either oxygen depletion associated with winter kill and/or lake turnover effect. 10 fish were reported as killed. The continuance of the IR Category 2b listing is based on IDNR's 2012 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 (2010-2012) 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 2b of Iowa’s 2014 Integrated Report.
The ISU and UHL lake surveys data from 2008-2012 show one violation of the Class B(LW) criterion for ammonia in 15 samples. The data show 2 violations of the Class B(LW) criterion for dissolved oxygen in 15 samples. Based on IDNR’s methodology these violations are not significantly greater than 10% of the samples and therefore do not suggest impairment of the Class B(LW) uses of Badger Creek Lake. The data also shows no violations in 15 samplesof the Class A1,B(LW) criterion for pH.
Fish consumption uses were assessed (monitored) as “fully supported” based on results of U.S. EPA/IDNR fish contaminant (RAFT) monitoring at Badger Creek Lake in 2011. The composite samples of fillets from largemouth bass and black bullhead had low levels of contaminants. Levels of primary contaminants in the composite sample of largemouth bass fillets were as follows: mercury: 0.124 ppm. Levels of primary contaminants in the composite sample of black bullhead fillets were as follows: mercury: 0.0315 ppm; total PCBs: 0.09 ppm; and technical chlordane: <0.03 ppm. The existence of, or potential for, a fish consumption advisory is the basis for Section 305(b) assessments of the degree to which Iowa’s lakes and rivers support their fish consumption uses. The fish contaminant data generated from the YEAR RAFT sampling conducted at this WATERBODY TYPE show that the levels of contaminants do not exceed any of the advisory trigger levels, thus indicating no justification for issuance of a consumption advisory for this waterbody.
