Lake Hendricks IA 01-WPS-356
Howard County S19T99NR14W 0.5 mi NE of Riceville.
- Cycle
- 2022
- Release Status
- Final
- Overall IR
- 5 - Water is impaired or threatened and a TMDL is needed.
- Trophic
- Eutrophic
- Trend
- Stable
- Created
- 12/17/2021 10:12:23 AM
- Updated
- 2/17/2022 8:45:25 AM
The Class A1 use was assessed as “not supported” due to violations of the state’s criterion for pH and aesthetically objectionable conditions caused by algae blooms. The level of inorganic suspended solids was relatively low and does not suggest water quality problems due to non-algal turbidity. The Class BLW use was assessed as “not supported” due to violations of the state criterion for pH. The Class HH (fish consumption) use was assessed as "fully supported" based on fish tissue sampling data.
Data Sources: Data Source Data Source ID Data Type Data Age Site ID Site Name Site Description Iowa DNR 6 WQ CY 2016-2019 22450001 Lake Hendricks Lake Hendricks Deep
Point Iowa DNR 6 FT See Below 79 Lake Hendricks
Class A1 - Indicator
Bacteria: No Data 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 22450001 6 12 / 4 7.9 9.3 8.6 3 4 NO Monitored Full According to DNR's methodology, alakemust meet water quality standards for two consecutive cycles to suggest de-listing. Therefore, Lake Hendricks will remain listed for the 2022 cycle as "not supported" its Class A1 uses due to pH. Site ID Data Source ID Parameter Name # Samples / # Years Minimum Value Maximum Value Median Value Median TSI Violation? Assessment Type Support Level 22450001 6 Chlorophyll a TSI 12 / 4 36 77 68 YES Monitored Not 22450001 6 Secchi TSI 12 / 4 48 80 70 YES Monitored Not 22450001 6 Total Phosphorus TSI 12 / 4 37 78 74 NA NA NA 22450001 6 Fixed suspended solids 12 / 4 0.4 17 4.2 NA NA NA Class BLW - Conventional 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 22450001 6 Ammonia 12 / 4 0.0003 0.279 0.08 NA 0 / 0 4 NO Monitored Full 22450001 6 Dissolved Oxygen 12 / 4 5.6 15.5 9.3 0 NA / NA 4 NO Monitored Full 22450001 6 pH 12 / 4 7.9 9.3 8.6 3 NA / NA 4 NO Monitored Full 22450001 6 Temperature 12 / 4 20 27.1 23.4 0 NA / NA 4 NO Monitored Full According to DNR's methodology, a river must meet water quality standards for two consecutive cycles to suggest de-listing. Therefore, Lake Hendricks will remain listed for the 2022 cycle as "not supported" its Class BLW uses due to pH. 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 22450001 6 6 25.50 72.2% 3.47 37.8% NO Evaluated NA 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) 79 tissue plug 2019 largemouth bass 10 33.2 0.168
Support Level Full