Cedar River IA 02-CED-479
from Rock Cr. nr Orchard (S24 T97N R17W Floyd Co.) to Iowa / Minnesota state line (S8 T100N R18W Mitchell Co.)
- Assessment Cycle
- 2020
- Release Status
- Final
- Data Collection Period
- Overall IR Category
- 5 - Water is impaired or threatened and a TMDL is needed.
- Trend
- Unknown
- Created
- 8/11/2020 1:27:24 PM
- Updated
- 10/14/2020 11:16:42 AM
Assessment Summary
The Class A1 use remains assessed as "partially supported" based on levels of indicator bacteria (E. coli) that exceeded Class A1 criteria. The Class BWW1 use remains assessed as "fully supported" based on water quality monitoring data. The Class HH use remains assessed as "partially supported" based on fish tissue sampling data and the existence of a one meal per week fish consumption advisory in this segment of the Cedar River. Note: A TMDL for indicator bacteria was approved by EPA in February 2010 for this segment. The approval of this TMDL moved the bacterial impairment for this segment from Iowa's list of Section 303(d) waters (Category 5a of the IR) to IR Category 4a (impaired; TMDL not required).
Assessment Explanation
Data
Sources: Data Source Data Source ID Data Type Data Age Site ID Site Name Site Description Iowa DNR 6 WQ CY 2014-2016 15660010 Cedar River at State Line ST Iowa DNR 6 FT See Below 132 Cedar River W of Osage Class
A1 - Indicator Bacteria: Site ID Data Source ID # Samples / # Years 2014 Geometric Mean 2015 Geometric Mean 2016 Geometric Mean Annual Geometric Mean Violation # Violations % Violations Significantly >10% Violations Assessment Type Support Level 15660010 6 18 / 3 86 356 120 Yes 4 22% 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 15660010 6 11 / 2 8.6 8.11 8.2 0 0% No Monitored Full Class
BWW1 - 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 15660010 6 Dissolved Oxygen 5 / 2 10.7 9.2 9.1 NA / 0 NA / 0% No Evaluated Full 15660010 6 pH 11 / 2 8.6 8.11 8.2 0 / NA 0% / NA No Monitored Full 15660010 6 Temperature 11 / 2 20.5 15.5 16.9 0 / 0 0% / 0% No Monitored Full Class
HH – Fish Tissue Sampling: Site ID Date Species Name Biopart # in sample Hg result Hg violation (>0.3)? Assessment Type Support Level 132 8/6/2009 smallmouth bass fillet 3 0.351 Yes Evaluated Partial A
one meal/week consumption advisory for mercury exists on this segment of the Cedar
River – see Iowa Consumption Advisories
Assessment Key Dates
| 8/6/2009 | Fish Tissue Monitoring |
| 4/22/2014 | Fixed Monitoring Start Date |
| 10/10/2016 | Fixed Monitoring End Date |
Methods
| 150 | Monitoring data more than 5 years old |
| 220 | Non-fixed station physical/chemical monitoring (conventional pollutant only) |
| 260 | Fish tissue analysis |
| 420 | Indicator bacteria monitoring |