South Fork Chariton River IA 05-CHA-1328
from confluence with Ninemile Cr. (S4 T69N R22W Wayne Co.) to outfall of Bob White Lake in S4 T68N R22W Wayne Co.
- Cycle
- 2020
- Release Status
- Final
- Overall IR
- 5 - Water is impaired or threatened and a TMDL is needed.
- Trend
- Improving
- Trend Comment
- Monitoring from 2000-2002 showed impairments related to low levels of dissolved oxygen. Levels of dissolved oxygen appear to have improved over the last 12 years of monitoring.
- Created
- 9/30/2020 8:19:33 AM
- Updated
- 11/23/2020 3:51:17 PM
The presumptive Class A1 use remains assessed as "partially supported" due to levels of indicator bacteria (E. coli) that exceeded state water quality criteria. The Class BWW2 use remains assessed as “partially supported” based on biological sampling data and continuous dissolved oxygen and temperature monitoring data.
Data
Sources: Data Source Data Source ID Data Type Data Age Site ID Site Name Site Description USACE 12 WQ CY 2010-2014 15930002 South Fork Chariton River (Site RA-35) Iowa DNR 6 WQ CY 2016 12930003 South Fork Chariton River near Corydon Iowa DNR 6 BIO See Below 906 South Fork Chariton River Corydon Presumptive
Class A1 - Indicator Bacteria: 2010-2012 Site ID Data Source ID # Samples / # Years 2010 Geometric Mean 2011 Geometric Mean 2012 Geometric Mean Annual Geometric Mean Violation # Violations % Violations Significantly >10% Violations Assessment Type Support Level 15930002 12 15 / 3 679 489 208 Yes 10 67% Yes Evaluated Partial Presumptive
Class A1 - pH: 2012-2014 Site ID Data Source ID # Samples / # Years Maximum Value Mean Value Median Value # Violations % Violations Significantly >10% Violations Assessment Type Support Level 15930002 12 38 / 3 8 7.6 7.6 0 0% No Evaluated Full Presumptive
Class A1 - pH: 2016 Site ID Data Source ID # Samples / # Years Maximum Value Mean Value Median Value # Violations % Violations Significantly >10% Violations Assessment Type Support Level 12930003 6 5 / 1 8 7.9 7.9 0 0% No Evaluated Full Class
BWW2 - Conventional Parameters: 2012-2014 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 15930002 12 Ammonia 24 / 3 0.78 0.1 0.05 0 / 0 0% / 0% No Evaluated Full 15930002 12 Chloride 17 / 3 17 8.4 7.3 0 / 0 0% / 0% No Evaluated Full 15930002 12 Dissolved oxygen 38 / 3 12.2 8.4 8 NA / 0 NA / 0% No Evaluated Full 15930002 12 pH 38 / 3 8 7.6 7.6 0 / NA 0% / NA No Evaluated Full 15930002 12 Temperature 38 / 3 25.3 17 18.3 0 / 0 0% / 0% No Evaluated Full Class
BWW2 - Conventional Parameters: 2016 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 12930003 6 Ammonia 6 / 1 0.07 0.06 0.05 0 / 0 0% / 0% No Evaluated Full 12930003 6 Chloride 6 / 1 31 16 13 0 / 0 0% / 0% No Evaluated Full 12930003 6 Dissolved oxygen 6 / 1 6.5 6 6 NA / 0 NA / 0% No Evaluated Full 12930003 6 pH 5 / 1 8 7.9 7.9 0 / NA 0% / NA No Evaluated Full 12930003 6 Sulfate 6 / 1 30 24 24 0 / 0 0% / 0% No Evaluated Full 12930003 6 Temperature 6 / 1 24.3 22.8 23 0 / 0 0% / 0% No Evaluated Full Class BWW2 - Biological
Sampling: Benthic
Macroinvertebrates: BioNet Site ID Date Drainage Area (mi2) Ecoregion Major Drainage/ Thermal BM Sample Gear BMIBI score BMIBI Class 40a BMIBI BIT BMIBI Pass/ Fail 906 9/6/16 37 40a MO/WW Surb 41 Fair 41 Pass 906 8/8/16 37 40a MO/WW Surb 51 Fair 41 Pass 906 9/12/12 37 40a MO/WW ArtSub 20 Poor 41 Fail Fish: BioNet Site ID Date Drainage Area (mi2) Ecoregion Major Drainage/ Thermal Riffle Stream? FIBI score FIBI Class 40a FIBI BIT FIBI Pass/ Fail 906 8/8/16 37 40a MO/WW NA 35 Fair 33 Pass 906 9/12/12 37 40a MO/WW NA 28 Fair 33 Fail Overall: Community Assessment Type Assessment Result Support Level Earned IR Category Actual IR Category Reason Benthic
Macroinvertebrates Evaluated Pass (2/3) Full
Fish Evaluated Fail (1/2) Partial
Overall Evaluated Fail Partial 3bc 5bt Assessment
was evaluated because it included samples not collected in the last five
years. Class BWW2 – Continuous Monitoring
Data: The
results of continuous dissolved oxygen (DO) and temperature monitoring in 2012
for the DNR/SHL sampling project Class BWW2 suggest impairment of aquatic life
uses. The lowest DO concentration recorded in 70 days of continuous monitoring
was 1.9 mg/L. The daily DO minimum concentration failed to meet the 24-hour DO
criterion (4 mg/L) in 48 of 70 days and the 16-hour DO criterion (5 mg/L) in 30
of 70 days. The percentages exceeding the 24-hour and 16-hour DO criteria
(68.6% and 42.9%, respectively) were greater than (failing) the 10% impairment
threshold used to assess conventional water quality parameters. The associated statistical
analysis confidence level was high (>90%). The maximum stream temperature
recorded during the sensor deployment period was 35.7 degrees (C). The
temperature criterion for warm water interior streams (32 C) was exceeded in 24
of 70 days. The percentage exceeding (34.3%) was greater than (failing) the 10%
impairment threshold with high statistical confidence (>90%). Based on these
data, the BWW2 aquatic life use is assessed as impaired for DO and temperature.
The assessment type is “evaluated” because it is based on data collected from a
single year within the current data assessment period. In order to meet the
requirements for a “monitored” assessment, the DNR’s continuous monitoring
assessment methodology requires monitoring data from two or more years within
the assessment period.