Hickory Grove Lake IA 03-SSK-950
Story County S24T83NR22W 2.5 mi SW of Colo.
- Assessment Cycle
- 2024
- Release Status
- Pending
- Data Collection Period
- Overall IR Category
- 5 - Water is impaired or threatened and a TMDL is needed.
- Trophic
- Eutrophic
- Trend
- Stable
- Created
- 11/1/2023 8:12:59 AM
- Updated
- 2/2/2024 3:45:17 PM
Assessment Summary
The Class A1 use was assessed as “not supported” due to levels of indicator bacteria that exceeded Iowa’s water quality standard and aesthetically objectionable conditions caused by non-algal turbidity. The Class BLW use was assessed (monitored) as “fully supported.” The Class HH (fish consumption) use was assessed as "fully supported" based on fish tissue sampling data. Note: A TMDL for indicator bacteria E. coli at Hickory Grove Lake was prepared by DNR and approved by EPA in June 2020. Because not all of the section 303(d) impairments identified for the current assessment/listing cycle (Turbidity) are addressed in the TMDL, this waterbody remains in Category 5a (impaired; TMDL required) for the current assessment/listing cycle.
Assessment Explanation
Data Sources: Data Source Data Source ID Data Type Data Age Site ID Site
Name Site
Description Iowa DNR 6 WQ CY 2018-2022 22850001 Hickory
Grove Lake (maximum water depth)
Iowa DNR 6 FT See Below Hickory Grove Lake Hickory Grove Park Class A1 - Indicator Bacteria: No Data. See previous 2020 assessments for results. 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 22850001 6 6 / 2 7.4 8.6 8.2 0 3 NO Evaluated 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 22850001 6 Chlorophyll a TSI 6 / 2 37 63 56 NO Evaluated Full 22850001 6 Secchi TSI 6 / 2 46 70 61 NO Evaluated Full 22850001 6 Total Phosphorus TSI 6 / 2 54 85 62 NA NA NA 22850001 6 Inorganic suspended solids 6 / 2 0.6 5 2.4 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 22850001 6 Dissolved Oxygen 6 / 2 3.6 11.2 8.7 1 NA / NA 3 NO Evaluated Full 22850001 6 pH 6 / 2 7.4 8.6 8.2 0 NA / NA 3 NO Evaluated Full 22850001 6 Temperature 6 / 2 18.5 26.5 23.6 0 NA / NA 3 NO Evaluated 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 22850001 6 1 0.018825858 0% 0.018825858 0% 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 22850001 6 Ammonia 6 / 2 0.228 0.11 0.11 0 / 0 NO Evaluated 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) 1300 fillet 2013 channel catfish 5 45 0.09 <0.2 <0.6 1300 tissue plug 2013 largemouth bass 5 32.9 0.239
Support Level Full
1300
Assessment Key Dates
| 6/12/2018 | Monitoring Start |
| 9/28/2022 | Monitoring End |
| 8/2/2013 | Fish Tissue Monitoring |
| 9/16/2013 | Fish Tissue Monitoring |
Methods
| 150 | Monitoring data more than 5 years old |
| 200 | Physical/Chemical Monitoring |
| 260 | Fish tissue analysis |
| 340 | Primary producer surveys (phytoplankton/periphyton/macrophyton) |
| 420 | Indicator bacteria monitoring |