Fogle Lake IA 05-GRA-1795

Assessment Comments

Assessment is based on: (1) results of the statewide survey of Iowa lakes conducted from 2004 through 2007 by Iowa State University (ISU), (2) results of the statewide ambient lake monitoring program conducted from 2005 through 2008 by University Hygienic Laboratory (UHL), and (3) information from the IDNR Fisheries Bureau.

Basis for Assessment

SUMMARY: NOTE: This lake is not designated for Class A1 uses.   The Class B(LW) (aquatic life) uses are assessed (monitored) as “fully supported.”  Fish consumption uses remain “not assessed.”  Sources of data for this assessment include (1) results of the statewide survey of Iowa lakes conducted from 2004 through 2007 by Iowa State University (ISU), (2) results of the statewide ambient lake monitoring program conducted from 2005 through 2008 by University Hygienic Laboratory (UHL), and (3) information from the IDNR Fisheries Bureau.

EXPLANATION: For the 2010 reporting cycle results from the ISU statewide survey of lakes and the UHL ambient lake monitoring program show good water quality at Fogle Lake.   Using the median values from these surveys from 2004 through 2008 (approximately 19 samples), Carlson’s (1977) trophic state indices for Secchi depth, chlorophyll a, and total phosphorus were 59, 60, and 61 respectively for Fogle Lake.   According to Carlson (1977) the Secchi depth and chlorophyll a values place Fogle Lake at the upper end of the eutrophic category while the total phosphorus value places Fogle Lake in between the eutrophic and hypereutrophic categories.   These values suggest relatively low levels of chlorophyll a and suspended algae in the water, relatively good water transparency, and moderately high levels of phosphorus in the water column.  

The levels of inorganic suspended solids at this lake were relatively low and do not suggest an impairment due to non-algal turbidity.   The median level of inorganic suspended solids in Fogle Lake (2.0 mg/L) was the 20th lowest median of the 132 lakes sampled by the ISU and UHL programs.

Data from the 2004-2008 ISU and UHL surveys suggest a moderate population of cyanobacteria exists at Fogle Lake, which does not suggest water quality problems due to nuisance algae blooms.   These data show that cyanobacteria comprised 73% of the phytoplankton wet mass at this lake.   The median cyanobacteria wet mass (11.5 mg/L) was the 54th lowest of the 132 lakes sampled.  

The Class B(LW) (aquatic life) uses are assessed as “fully supported” based on information from the IDNR Fisheries Bureau, and results of the ISU and UHL lake surveys.   Information from the IDNR Fisheries Bureau suggests that Fogle Lake does not show any obvious water quality problems.   Data from the ISU and UHL lake surveys from 2004-2008 show no violations of the Class B(LW) criteria for ammonia in 18 samples, dissolved oxygen in 19 samples, or pH in 19 samples.   These results suggest "full support" of the Class B(LW) uses at Fogle Lake.

Fish consumption uses remain "not assessed" due to the lack of fish contaminant monitoring in this lake.