For the 2016 assessment/listing cycle, the Class A1 (primary contact recreation) uses of Volga Lake are assessed (monitored) as "partially supported" due to poor water transparency and aesthetically objectionable conditions caused by algae blooms based on information from the ISU lake survey. Using the median values from these surveys from 2010-2014 (approximately 15 samples), Carlson 's (1977) trophic state indices for Secchi depth, chlorophyll a, and total phosphorus were 65, 69, and 65 respectively for Volga Lake. According to Carlson (1977) the Secchi depth, chlorophyll a, and total phosphorus values all place Volga Lake in the Eutrophic category. These values suggest high levels of chlorophyll a and suspended algae in the water, poor water transparency, and high levels of phosphorus in the water column. The data show no violations of the Class A1 criterion for pH in 15 samples.

Note: A TMDL for impairments due to algae and non-algal turbidity at this lake was prepared and approved by EPA in July 2014.  The approval of this TMDL moves the impairments due to algae and non-algal turbidity from Iowa's list of Section 303(d) waters (Category 5a of the Integrated Report) to IR Category 4a (impaired; TMDL not required).  

The level of inorganic suspended solids was moderately high at Volga Lake, and does suggest that non-algal turbidity may contribute to the impairment at this lake. The median level of inorganic suspended solids in Volga Lake (5 mg/L) was ranked 88th among the 138 lakes by the ISU lake survey.

Data from the 2010-2014 ISU lake survey suggest a moderately large population of cyanobacteria exists at Volga Lake. These data show that cyanobacteria comprised 91% of the phytoplankton wet mass at this lake. The median cyanobacteria wet mass (34.4 mg/L) was ranked 103rd of the 138 lakes sampled.

The Class B(LW) (aquatic life) uses are assessed (evaluated) as “partially supported” based on information from the IDNR Fisheries Bureau and results from the ISU lake surveys. Based on information from the IDNR Fisheries Bureau, this lake is highly susceptible to gully erosion, siltation, and nutrient loading. In addition, Volga lake contains a high number of carp making it difficult for establishment of submerged aquatic vegetation. Results of the ISU lake survey from 2010-2014 however, show there were no violations of the criterion for ammonia in 15 samples(0%), 3 violations of the criterion for dissolved oxygen in 15 samples(20%), and no violations of the criterion for pH in 15 samples(0%). Based on IDNR's assessment methodology these violations are not significantly greater than 10% of the samples and therefore suggest (fully supported/monitored) of the Class B(LW) uses of Volga Lake.

Fish consumption uses were assessed (monitored) as “fully supported” based on results of U.S.   EPA/IDNR fish contaminant (RAFT) monitoring at Volga Lake in 2010.    The composite samples of fillets from largemouth bass and channel catfish had low levels of contaminants.    Levels of primary contaminants in the composite sample of largemouth bass fillets were as follows: mercury: 0.119 ppm.   Levels of primary contaminants in the composite sample of channel catfish fillets were as follows: mercury: 0.0948 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 2010 RAFT sampling conducted at this lake 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.