Lake Smith IA 04-EDM-981
Kossuth County S36T96NR29W 3 mi. N of Algona.
- Cycle
- 2026
- Current Phase
- Public Comment
- Overall IR
- 5 - Water is impaired or threatened and a TMDL is needed.
- Trophic
- Eutrophic
- Trend
- Stable
- Created
- 10/27/2025 3:09:47 PM
- Updated
- 11/17/2025 2:14:19 PM
The Class A1 use was assessed (monitored) as “not supported” due to high levels of algae (chlorophyll a) and violations of the Class A1 criterion for pH. The Class BLW use was assessed (monitored) as “not supported” due to violations of the Class BLW criterion for pH. All other designated uses are “not assessed.” A TMDL for noxious aquatic plants at Lake Smith was prepared by DNR and approved by EPA in 2005. The basis of the impairment at this lake was high populations of cyanobacteria (=noxious aquatic plants). Based on recent monitoring, a fish kill in the winter of 2000-01 and a subsequent lake renovation has significantly decreased the amount of cyanobacteria in this lake. Recent ISU lake monitoring data strongly suggest that the impairment due to noxious aquatic plants (cyanobacteria) no longer exists. Non-cyanobacteria algal populations, however, remain elevated at this lake and suggest "non support" of the Class A1 use. Because only the algae populations are addressed in the TMDL this lake is placed in IR Category 5a (impaired; TMDL needed) for the current assessment cycle.
Data Sources: Data Source Data Source ID Data Type Data Age Site ID Site
Name Site
Description Iowa DNR 6 WQ CY 2021-2024 22550001 Smith
Lake
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 22550001 6 12 / 4 8.11 9.46 8.81 5 4 YES MONITORED NOT 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 22550001 6 Chlorophyll a TSI 12 / 4 45 79 66 YES MONITORED NOT 22550001 6 Secchi TSI 12 / 4 45 75 64 NO MONITORED FULL 22550001 6 Total Phosphorus TSI 12 / 4 60 87 77 NA NA NA 22550001 6 Fixed suspended solids 12 / 4 1.9 9 3 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 22550001 6 Dissolved Oxygen 11 / 4 7 15.9 9.8 0 NA / NA 3 NO MONITORED FULL 22550001 6 pH 12 / 4 8.11 9.46 8.81 5 NA / NA 4 YES MONITORED NOT 22550001 6 Temperature 12 / 4 19.8 27.4 24.3 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 22550001 6 4 14.4863 79.46% 1.2087 2.97% 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 22550001 6 Ammonia 12 / 4 0.073 0.04 0.03 0 / 0 NO MONITORED FULL
Class HH - No Data: The previous fish tissue results were removed based on the age of the data.