Nine Eagles Lake IA 05-GRA-1361
Decatur County S18T67NR25W 3.5 mi. SE of Davis City.
- Cycle
- 2020
- Release Status
- Final
- Overall IR
- 5 - Water is impaired or threatened and a TMDL is needed.
- Trophic
- Mesotrophic
- Trend
- Stable
- Created
- 8/21/2020 2:01:37 PM
- Updated
- 10/14/2020 2:44:40 PM
The Class A1 uses are assessed (monitored) as “partially supported” due to levels of indicator bacteria that exceed state water quality standards. The Class BLW uses are assessed (monitored) as “fully supported.” Fish consumption uses remain assessed (monitored) as “partially supported” (IR 5a) due to the existence of a fish consumption advisory. The Class C uses remain “not assessed” (IR 3a) due to a lack of enough information upon which to base an assessment. Note: A TMDL for turbidity at Nine Eagles Lake was prepared by DNR and approved by EPA in 2001. Because the section 303(d) impairments due to indicator bacteria and mercury in fish tissue at Nine Eagles Lake were not addressed in the TMDL, this waterbody remains in Category 5a (impaired; TMDL required) for the current assessment cycle.
Sources of
Data: Data Source Data Source ID Data Type Data Age Site ID Site Name Site Description Iowa DNR 6 WQ CY 2016-2018 21270001 Nine Eagles Beach (Nine Eagles State Park)
Iowa DNR 6 WQ CY 2014-2018 22270002 Nine Eagles Lake Lake Deep Point Iowa DNR FT See Below 195 Nine Eagles Lake
Class A1 -
Indicator Bacteria: Site ID Data Source ID # Samples / # Years 2016 Geometric Mean 2017 Geometric Mean 2018 Geometric Mean Annual Geometric Mean Violation # Violations % Violations Significantly >10% Violations Assessment Type Support Level 21270001 6 44 / 3 62.78 196.8 53.48 Yes 15 34% YES Monitored Partial Class A1 - pH: Site ID Data Source ID # Samples / # Years Maximum Value Mean Value Median Value # Violations % Violations Significantly >10% Violations Assessment Type Support Level 22270002 6 15 / 5 8.51 8.29 8.3 0 0% 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 22270002 6 Chlorophyll a TSI 15 / 5 31 64 41 NO Monitored Full 22270002 6 Secchi TSI 15 / 5 38 67 47 NO Monitored Full 22270002 6 Total Phosphorus TSI 15 / 5 28 55 46 NA NA NA 22270002 6 Inorganic suspended solids 15 / 5 0.6 11 2 NA NA NA Class BLW -
Conventional Parameters: Site ID Data Source ID Parameter Name # Samples / # Years Maximum Value Mean Value Median Value # Acute / Chronic Violations % Acute/ Chronic Violations Significantly >10% Violations Assessment Type Support Level 22270002 6 Ammonia 15 / 5 0.24 0.03 0.01 0 / 0 0% / 0% NO Monitored Full 22270002 6 Dissolved oxygen 15 / 5 10.4 8.3 8.4 NA / 0 NA / 0% NO Monitored Full 22270002 6 pH 15 / 5 8.51 8.29 8.3 0 / NA 0% / NA NO Monitored Full 22270002 6 Temperature 15 / 5 28.4 24.3 24.9 0 / 0 0% / 0% 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 Wet Mass = 75th
Percentile Assessment Type Support Level 22270002 6 11 30.675 91.4 % 2.157 81.5 % NO Evaluated NA Class C -
Conventional Parameters: Site ID Data Source ID Parameter Name # Samples / # Years Maximum Value Mean Value Median Value # Violations % Violations Significantly >10% Violations Assessment Type Support Level 22270002 6 Inorganic nitrogen (nitrate and nitrite) 15 / 5 0.035 0.027 0.03 0 0% NO Monitored Full The Class C
uses are not assessed due to the lack of data sufficient for developing a valid
assessment of support of the Class C uses. Class HH - Fish
Tissue Sampling: Site ID Date Species Name Biopart # in sample chlordane result chlordane violation? PCBs result PCBs violation? Hg result Hg violation? Assessment Type Support Level 195 7/8/15 largemouth bass plug 5
0.498 Yes Monitored Partial 195 7/30/09 largemouth bass fillet 4
0.534 Yes Evaluated Partial