Lake Smith IA 04-EDM-981
Kossuth County S36T96NR29W 3 mi. N of Algona.
- Cycle
- 2022
- Release Status
- Final
- Overall IR
- 4 - Water is impaired or threatened and a TMDL has been completed or is not needed.
- Trophic
- Eutrophic
- Trend
- Stable
- Created
- 12/27/2021 1:20:57 PM
- Updated
- 1/28/2022 6:54:44 AM
The Class A1 use was assessed (monitored) as “not supported” due to high levels of algae (chlorophyll a) and poor water clarity. 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. 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 algae populations are addressed in the TMDL this lake is placed in IR Category 4a (impaired; TMDL approved) 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 2016-2019 22550001 Smith Lake Iowa DNR 6 FT See Below 310 Smith Lake Smith Lake Park
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 7.8 9.8 8.6 3 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 22550001 6 Chlorophyll a TSI 12 / 4 44 75 59 NO Monitored Full 22550001 6 Secchi TSI 12 / 4 47 76 64 NO Monitored Full 22550001 6 Total Phosphorus TSI 12 / 4 58 85 68 NA NA NA 22550001 6 Inorganic suspended solids 12 / 4 0.3 14.2 1.4 NA NA NA Although the index value for Chlorophyll a is below the
impairment trigger of 65 for this assessment cycle, the Class A1 use of Smith Lake remains "not supported" due to aesthetically objectionable
conditions. Based on DNR's methodology, the median TSI value for Chlorophyll a
must be 63 or less for two consecutive assessment/listing cycles before a lake can be removed from the state's Section 303(d) list (IR Category 5). Therefore,
Smith Lake will remain listed as "not supported" for the 2022
assessment/listing cycle. 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 22550001 6 Ammonia 12 / 4 0.0003 0.088 0.04 NA 0 / 0 4 NO Monitored Full 22550001 6 Dissolved Oxygen 12 / 4 5.4 12.8 10.1 0 NA / NA 4 NO Monitored Full 22550001 6 pH 12 / 4 7.8 9.8 8.6 3 NA / NA 4 NO Monitored Full 22550001 6 Temperature 12 / 4 15.9 28.8 22.9 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 6 39.54 99.3% 2.92 7.1% 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) 310 fillet 2013 channel catfish 4 56.5 0.06 <0.2 <0.6 310 tissue plug 2013 largemouth bass 5 36.6 0.248
Support Level Full