Lake Anita IA 05-NSH-1435
Cass County S32T77NR34W 1/2 mi S Anita.
| Cycle Added | Class | Cause | Data Source | Rationale |
|---|---|---|---|---|
| 2024 | Class A1 | Turbidity: Secchi Disk Transparency | Ambient monitoring: Iowa DNR-lakes | TMDL preparation and approval |
The Class A1 use was assessed (monitored) as “not supported” due to non-algae turbidity and algae blooms that violated Iowa's narrative criteria protecting against aesthetically objectionable conditions. The Class BLW use was assessed (monitored) as “not supported” due to violations of the dissolved oxygen criteria. The Class HH (fish consumption) use was assessed (monitored) as “fully supported” based on fish tissue sampling data. Note: A TMDL for algae at Lake Anita was prepared by DNR and approved by EPA in 2023. Additionally, a TMDL for turbidity at Lake Anita was prepared by DNR and approved by EPA in 2025. Because not all Section 303(d) impairments identified for the current assessment/listing cycle (dissolved oxygen) are addressed by the TMDL, this waterbody was placed in IR Category 5a (impaired; TMDL needed).
Data Sources: Data Source Data Source ID Data Type Data Age Site ID Site
Name Site
Description Iowa DNR 6 WQ CY 2022-2024 21150001 Lake
Anita Beach
Iowa DNR 6 WQ CY 2020-2024 22150002 Lake
Anita
Iowa DNR 6 FT See Below 1100 Lake
Anita
Class A1 - Indicator Bacteria: Site ID Data Source ID # Samples per Year (2022/ 2023/2024) 2022 Geometric Mean 2023 Geometric Mean 2024 Geometric Mean Violates Annual Geometric Mean? # 2022 SSM violations / SSM Violations needed for impairment # 2023 SSM violations / SSM Violations needed for impairment # 2024 SSM violations / SSM Violations needed for impairment Violates Annual SSM Significantly >10% Rule? Assessment Type Support Level 21150001 6 15/14/15 39 45 24 NO 0 / 4 0 / 4 1 / 4 NO MONITORED FULL Class A1 - pH Site ID Data Source ID # Samples / # Years Minimum Value Maximum Value Mean Value # Violations Violations needed for impairment Violates Significantly >10% Rule? Assessment Type Support Level 22150002 6 15 / 5 7.5 8.5 8 0 4 NO MONITORED FULL Class A1 - Lake TSI's Site ID Data Source ID Parameter Name # Samples / # Years Minimum Value Maximum Value Median Value Median TSI Violation? Assessment Type Support Level 22150002 6 Chlorophyll a TSI 15 / 5 38 76 67 YES MONITORED NOT 22150002 6 Secchi TSI 15 / 5 49 70 66 YES MONITORED NOT 22150002 6 Total Phosphorus TSI 15 / 5 50 65 60 NA NA NA 22150002 6 Fixed suspended solids 15 / 5 0.7 9 2 NA NA NA Class BLW - Binomial Parameters: Site ID Data Source ID Parameter Name # Samples / # Years Minimum Value Maximum Value Mean Value # Violations # Acute / Chronic Violations Violations needed for impairment Violates Significantly >10% Rule? Assessment Type Support Level 22150002 6 Dissolved Oxygen 15 / 5 3.3 11.6 6.8 4 NA / NA 4 YES MONITORED NOT 22150002 6 pH 15 / 5 7.5 8.5 8 0 NA / NA 4 NO MONITORED FULL 22150002 6 Temperature 15 / 5 18.2 28.9 24 0 NA / NA 4 NO MONITORED FULL Class BLW - Lake Planktonic Cyanobacteria: Site ID Data Source ID # Samples Maximum Cyanobacteria Wet Mass Maximum Cyanobacteria % Composition Median Cyanobacteria Wet Mass Median Cyanobacteria % Composition Median Cyanobacteria Concentration = 75th Percentile Assessment Type Support Level 22150002 6 6 57.16733713 97.02% 3.228048285 64.04% NO EVALUATED NA Class BLW - Toxic Parameters: Site ID Data Source ID Parameter Name # Samples / # Years Maximum Value Mean Value Median Value # Acute / Chronic Violations >1 Acute / Chronic Violation Assessment Type Support Level 22150002 6 Ammonia 15 / 5 0.318 0.07 0.03 0 / 0 NO MONITORED FULL Class HH - Fish
Tissue Sampling: Site ID Biopart Year Species # in sample / # of samples Avg Length (cm) (Avg) Hg (ppm) Chlordane (ppm) Sum PCBs (ppm) 1100 tissue plug 2019 black crappie 2 18.9 0.067
1100 tissue plug 2020 crappie spp. 8 27.5 0.167
1100 tissue plug 2019 largemouth bass 10 34.6 0.196
Support Level Full