For the 2016 assessment/listing cycle, the Class A1 (primary contact recreation) uses of East Lake are assessed (monitored) as "not supported" due to poor water transparency, aesthetically objectionable conditions caused by algae blooms and due to frequent violations of the state criterion for pH 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 70, 70, and 84 respectively for East Lake. According to Carlson (1977) the Secchi depth, chlorophyll a, and total phosphorus values all place East Lake in the Hypereutrophic category. These values suggest very high levels of chlorophyll a and suspended algae in the water, very poor water transparency, and extremely high levels of phosphorus in the water column. The data show 5 violations of the Class A1 criterion for pH in 15 samples (33%).

The level of inorganic suspended solids was moderately high at East Lake, and does suggest that non-algal turbidity may contribute to the impairment at this lake. The median level of inorganic suspended solids in East Lake (6.3 mg/L) was ranked 100th 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 East Lake. These data show that cyanobacteria comprised 73% of the phytoplankton wet mass at this lake. The median cyanobacteria wet mass (23.2 mg/L) was ranked 73rd of the 138 lakes sampled.

The Class B(LW) (aquatic life) uses are assessed (monitored) as "not supported" due to violations of the Class A1,B(LW) criterion for pH. Poor water quality that put the lake at risk for a fish kill based on information from the IDNR Fisheries bureau. Results of the ISU lake survey from 2010-2014 show there were no violations of the criterion for ammonia in 15 samples(0%), no violations of the criterion for dissolved oxygen in 15 samples(0%), and 5 violations of the criterion for pH in 15 samples(33%). Based on IDNR's assessment methodology these violations are significantly greater than 10% of the samples and therefore suggest impairment (not supported/monitored) of the Class B(LW) uses of East Lake.

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

NOTE: A TMDL for algae and turbidity for East Lake was completed by IDNR and approved by EPA in 2008..   Thus, these impairments are moved from IR Category 5a (impaired; TMDL required) to Category 4a (impaired; TMDL approved).   Because not all the impairments identified for this lake are covered by this TMDL (pH), this lake remains in IR Category 5a.