Willow Creek IA 06-LSR-1626
mouth (S17 T94N R36W Clay Co.) to confluence with unnamed tributary in NW 1/4 S31 T95N R37W Clay Co.
- Cycle
- 2020
- Release Status
- Final
- Overall IR
- 5 - Water is impaired or threatened and a TMDL is needed.
- Trend
- Unknown
- Created
- 6/18/2020 10:39:28 AM
- Updated
- 10/12/2020 1:09:20 PM
| Cycle Added | Class | Cause | Data Source | Rationale |
|---|---|---|---|---|
| 2004 | Class BWW2 | Fish Kill: Caused By Animal Waste | Biological monitoring: Iowa DNR fish kill follow-up | New data: recovery of fish community from pollutant-caused fish kill |
The presumptive Class A1 primary contact recreation use remains assessed as "not supported" due to violations of the state water quality criteria for indicator bacteria in 2010. The Class BWW2 aquatic life use was assessed as “partially supported” based on 2009, 2011 and 2018 biological sampling data. The previous Category 5b impairment of the presumptive Class BWW1 aquatic life use due to fish kills was de-listed based on fish kill follow up sampling conducted in 2011 and 2018. All other designated uses were "not assessed".
Sources of Data: Data Source Data Source ID Data Type Data Age Site ID Site Name Site Description Iowa DNR 6 WQ CY 2010-2011 11210003 Willow Creek near Royal
Iowa DNR 6 BIO See Below 205 Willow Creek Royal Iowa DNR 6 BIO See Below 306 Willow Creek Rossie – REMAP #31 Presumptive Class
A1 - Indicator Bacteria: Site ID Data Source ID # Samples / # Years 2010 Geometric Mean Annual Geometric Mean Violation # Violations % Violations Significantly >10% Violations Assessment Type Support Level 11210003 6 12 / 1 1113 Yes 10 77% Yes Evaluated Not Presumptive 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 11210003 6 Ammonia 37 / 2 0.46 0.06 0.05 0 / 0 0% / 0% No Evaluated Full 11210003 6 Chloride 12 / 2 24 19 20 0 / 0 0% / 0% No Evaluated Full 11210003 6 Dissolved oxygen 19 / 2 12.5 9.2 9.6 NA / 0 NA / 0% No Evaluated Full 11210003 6 pH 19 / 2 8.5 7.9 7.9 0 / NA 0% / NA No Evaluated Full 11210003 6 Sulfate 12 / 2 64 46 47 0 / NA 0% / NA No Evaluated Full 11210003 6 Temperature 19 / 2 26.3 15.8 17.6 0 / 0 0% / 0% No Evaluated Full Presumptive
Class BWW1 - Biological Sampling: Benthic
Macroinvertebrates: BioNet Site ID Date Drainage Area (mi2) Ecoregion Major Drainage/ Thermal BM Sample Gear BMIBI score BMIBI Class 47a BMIBI BIT BMIBI Pass/ Fail 306 8/1/18 51 47a MO/WW Hess 22 Poor 54 Fail 205 9/19/11 50 47a MO/WW Surb 51 Fair 54 Fail Fish: BioNet Site ID Date Drainage Area (mi2) Ecoregion Major Drainage/ Thermal Riffle Stream? FIBI score FIBI Class 47a FIBI BIT FIBI Pass/ Fail 306 8/1/18 51 47a MO/WW NA 41 Fair 43 Fail 205 9/19/11 50 47a MO/WW NA 54 Good 43 Pass 205 9/14/09 50 47a MO/WW NA 52 Good 43 Pass Overall: Community Assessment Type Assessment Result Support Level Earned IR Category Actual IR Category Reason Benthic
Macroinvertebrates Evaluated Fail (0/2) Partial Fish Evaluated Pass (2/3) Full
Overall Evaluated Fail Partial 3bc 5bt Assessment
is evaluated because it included samples not collected in the last five years. Presumptive
Class BWW1 – Fish kill Follow-Up Assessment: BioNet Site ID Stream Name Site Type Ecoregion Sample Date Fish per mile REMAP 25 %
fish/mile >REMAP 25
% fish/mile? 2000 305(b) fish taxa
present 2000 305(b) fish taxa
present % 205 Willow Creek Wadeable 47a 9/19/11 7624 524 Yes 9/9 100% (Pass) 306 Willow Creek Wadeable 47a 8/1/18 1370 524 Yes 7/9 78% (Pass) The
presumptive Class BWW1 aquatic life use previously resided in Category 5b
based on 2001, 2002, 2006 fish kills. This segment’s fish community was
sampled in 2011 and 2018 as part of the DNR fish kill follow-up sampling program.
The results from this follow-up sampling and comparison to ecoregion averages
suggest that the fish community of this segment is similar to non-fish kill
impacted streams. Based on the results of the fish kill follow-up sampling,
the Category for the fish kill assessment was changed from 5b to 3a (water
not assessed). Presumptive
Class BWW1 – Continuous Monitoring Data Assessment: The results of continuous monitoring for dissolved oxygen (DO) and
temperature in 2011 also suggest "full support" of the presumptive Class
BWW1 aquatic life use. The lowest DO concentration recorded in 34 days of
continuous monitoring was 4.9 mg/L. The daily DO minimum concentration failed
to meet the 24-hour DO criterion (4 mg/L) and the 16-hour DO criterion (5 mg/L)
in 0 of 34 days each. The percentages exceeding the 24-hour and 16-hour DO
criteria (0.0% each) were less than (passing) 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 31.6 degrees (C). The
temperature criterion for warmwater interior streams (32 C) was exceeded in 0
of 34 days. The percentage exceeding (0%) was less than (passing) the 10%
impairment threshold with high statistical confidence (>90%). Based on these
data, the BWW2 aquatic life use is assessed as not impaired due to 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.