Cedar River IA 02-CED-451
from Rock Run Cr. (S28 T80NR3W Cedar Co ) to Hwy 30 bridge at Cedar Rapids in S9 T82N R6W Linn 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
- 8/28/2020 7:37:27 AM
- Updated
- 10/16/2020 7:29:03 AM
Assessment Summary
The Class A1 use was assessed as "partially supported" due to levels of indicator bacteria (E. coli) that violated state water quality criteria. The Class BWW1 use remains assessed as "not supported" based on results of a 1998-99 statewide survey of freshwater mussels. The Class HH use was assessed as “fully supported” based on ambient water quality monitoring data. Note: A TMDL for indicator bacteria in this segment of Cedar River was prepared and approved by EPA in February 2010. The approval of this TMDL moved the bacteria impairment for this segment from Iowa's list of Section 303(d) waters (Category 5a of the IR) to IR Category 4a.
Assessment Explanation
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 10570001 Cedar River Downstream of Cedar Rapids
(DS1) Iowa DNR 6 BIO See Below 952 Cedar River Cedar Rapids -DS1 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 10570001 6 24 / 3 233.44 97.95 244.65 Yes 11 46% 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 10570001 6 36 / 3 9.1 8.3 8.3 1 3% 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 10570001 6 Ammonia 36 / 3 0.79 0.1 0.02 0 / 0 0% / 0% No Monitored Full 10570001 6 Chloride 36 / 3 43 24 24 0 / 0 0% / 0% No Monitored Full 10570001 6 Dissolved oxygen 36 / 3 17.2 11.6 11.7 NA / 0 NA / 0% No Monitored Full 10570001 6 pH 36 / 3 9.1 8.3 8.3 1 / NA 3% / NA No Monitored Full 10570001 6 Sulfate 36 / 3 49 26 27 0 / NA 0% / NA No Monitored Full 10570001 6 Temperature 36 / 3 27.8 12.6 12.4 0 / 0 0% / 0% No Monitored Full Class BWW1 -
Toxic Parameters: Site ID Data Source ID Parameter Name # Samples / # Years Maximum Value Mean Value Median Value # Acute / Chronic Violations % Acute/ Chronic Violations >1 Acute / Chronic Violation Assessment Type Support Level 10570001 6 Aluminum 9 / 2 1.7 0.728 0.84 0 / 0 0% / 0% No Evaluated Full 10570001 6 Arsenic 9 / 2 2.3 1.7 1.6 0 / 0 0% / 0% No Evaluated Full 10570001 6 Cadmium 9 / 2 0.025 0.025 0.025 0 / 0 0% / 0% No Evaluated Full 10570001 6 Chromium 9 / 2 1.1 0.71 0.72 0 / 0 0% / 0% No Evaluated Full 10570001 6 Copper 9 / 2 3.5 1.21 1 0 / 0 0% / 0% No Evaluated Full 10570001 6 Lead 9 / 2 0.14 0.067 0.05 0 / 0 0% / 0% No Evaluated Full 10570001 6 Nickel 9 / 2 3.1 2.2 2.2 0 / 0 0% / 0% No Evaluated Full 10570001 6 Selenium 9 / 2 1.8 1.26 1.3 0 / 0 0% / 0% No Evaluated Full 10570001 6 Zinc 9 / 2 3.6 1.62 1.2 0 / 0 0% / 0% No Evaluated Full Class BWW1 - Biological Sampling: Benthic Macroinvertebrates: BioNet Site ID Date Drainage Area (mi2) Ecoregion Major Drainage/Thermal BM Sample Gear BMIBI score BMIBI Class 47f BMIBI BIT BMIBI Pass/ Fail 952 8/24/15 6955 47f MS/WW Float ArtSub 56 Good 51 Pass 952 10/11/14 6955 47f MS/WW Float ArtSub 52 Fair 51 Pass Overall Assessment: Community Assessment Type Assessment Result Support Level Earned IR Category Actual IR Category Reason Benthic
Macroinvertebrates Evaluated Pass (2/2) Full 1 1 Assessment is evaluated because the drainage
area of the sample site is larger than calibrated range. Class BWW1 – Freshwater Mussel Sampling: Freshwater
Mussel Survey Avg. # Freshwater Mussel Species Avg. # Freshwater Mussel Species
Increase/Decrease Avg % Freshwater Mussel Species
Increase/Decrease Assessment Type Support Level IR Category 1984-85
(Frest 1987) 5 sites 5.6
1998-99
(Arbuckle et al. 2000) 5 sites 0.4 -5 -92% Evaluated Not 5b As
presented by Arbuckle et al. (2000), the potential causes of declines in
species richness of Iowa's freshwater mussels include siltation,
destabilization of stream substrate, stream flow instability, and high
instream levels of nutrients (phosphorus and nitrogen). Their study also
suggested the importance of stream shading provided by riparian vegetation to
mussel species richness. Class HH-F -
Toxic Parameters: Site ID Data Source ID Parameter Name # Samples / # Years Maximum Value Mean Value Median Value Number of Non - Detects Mean Value > Criterion or MCL Assessment Type Support Level 10570001 6 Cadmium 9 / 2 0.025 0.025 0.025 9 No All Non-Detect Full 10570001 6 Chromium 9 / 2 1.1 0.71 0.72 0 No Evaluated Full 10570001 6 Copper 9 / 2 3.5 1.21 1 0 No Evaluated Full 10570001 6 Nickel 9 / 2 3.1 2.2 2.2 0 No Evaluated Full 10570001 6 Selenium 9 / 2 1.8 1.26 1.3 0 No Evaluated Full 10570001 6 Zinc 9 / 2 3.6 1.62 1.2 0 No Evaluated Full
Assessment Key Dates
| 9/30/1999 | Biological Monitoring |
| 1/5/2016 | Fixed Monitoring Start Date |
| 12/6/2018 | Fixed Monitoring End Date |
| 10/11/2014 | Biological Monitoring |
| 8/24/2015 | Biological Monitoring |
| 2/1/2010 | TMDL Completed |
Methods
| 120 | Surveys of fish and game biologists/other professionals |
| 230 | Fixed station physical/chemical (conventional plus toxic pollutants) |
| 315 | Regional reference site approach |
| 320 | Benthic macroinvertebrate surveys |
| 420 | Indicator bacteria monitoring |