Wapsipinicon River IA 01-WPS-354
from town of McIntyre (S34 T100N R15W Mitchell Co.) to north line of S20 T100N R15W 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
- 8/25/2020 1:31:58 PM
- Updated
- 10/15/2020 2:10:20 PM
The Class A1 and the Class A2 uses remain assessed as “not supported” due to levels of indicator bacteria (E. coli) that violated state water quality criteria. The Class BCW1 use was assessed as "partially supported" based on biological sampling data, continuous dissolved oxygen and temperature monitoring data, and multiple fish kill investigations. 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 CY2010 11660001 Wapsipinicon River Site Wap-1 Iowa DNR 6 WQ CY2010 11660002 Wapsipinicon River Site 75/Wap-2 Iowa DNR 6 WQ CY2010 12660005 Wapsipinicon River Wapsipinicon SWMA Iowa DNR 6 BIO See Below 58 Wapsipinicon River Wapsipinicon River SWMA - McIntire Iowa DNR 6 BIO See Below 689 Wapsipinicon River Wap1 - McIntire Iowa DNR 6 BIO See Below 760 Wapsipinicon River Wap2 - McIntire 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 11660001 6 29
/ 2 4329 Yes 26 90% Yes Evaluated Not 11660002 6 16
/ 2 920 Yes 13 81% Yes Evaluated Partial 12660005 6 16
/ 2 1596 Yes 15 9% Yes Evaluated Not Class
A2 - 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 11660001 6 33
/ 2 3324 Yes 13 39% Yes Evaluated Not 11660002 6 20
/ 2 636 Yes 2 10% No Evaluated Partial 12660005 6 20
/ 2 1306 Yes 3 15% No Evaluated Not Class
BCW1 - Biological Sampling: Benthic
Macroinvertebrates: BioNet Site ID Date Drainage Area (mi2) Ecoregion Major Drainage/ Thermal BM Sample Gear CBI score CBI Class CBI BIT CBI Pass/ Fail 58 8/17/10 22 47c MS/CW ArtSub 37 NA 60 Fail 760 8/17/10 22 47c MS/CW Hess 43 NA 60 Fail 689 8/17/10 22 52b MS/CW ArtSub 33 NA 60 Fail 58 8/27/08 22 47c MS/CW ArtSub 37 NA 60 Fail 689 8/27/08 31 52b MS/CW ArtSub 37 NA 60 Fail Overall
Assessment:
Community Assessment Type Assessment Result Support Level Earned IR Category Actual IR Category Reason Benthic Macroinvertebrates Evaluated Fail (0/5) Partial 3bc 5bv Assessment
is evaluated because samples used to complete the assessment weren’t
collected in the last five years. Class BCW1 - Continuous Monitoring: The 2010 combined results of continuous dissolved oxygen (DO) and temperature monitoring at stations 11660001 (Wap-1), 11660002 (Wap-2), and 12660005 (SWMA) do suggest impairment of Class BCW1 aquatic life uses. The lowest DO concentration recorded in 51 combined days of continuous monitoring at the three bioassessment sites was 3.8 mg/L. The daily DO minimum concentration failed to meet the 24-hour DO criterion (5 mg/L) and the 16-hour DO criterion (7 mg/L) in 7 of 51 days and 23 of 51 days, respectively. The percentage exceeding the 24-hour criterion (14%) and was greater than (failing) the 10% impairment threshold used to assess conventional water quality parameters; however, the statistical analysis confidence level (< 90%) was not high. The percentage exceeding the 16-hour criterion (45.1%) and was greater than (failing) the 10% impairment threshold with high statistical confidence (>90%). The maximum stream temperature recorded during the sensor deployment period ranged from 23.3-25.7 degrees (C) among the three bioassessment sites. The BCW1 temperature criterion of 20 (C) was exceeded in 50 of 51 days. The combined percentage exceeding (98%) was greater than (failing) the 10% impairment threshold with high statistical confidence (>90%). Based on these data, the BCW1 aquatic life use is assessed as 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. Given the extremely high frequency of temperature criteria exceedances, follow-up continuous monitoring and an assessment of stream thermal dynamics are strongly recommended. Class BCW1 - Fish kill Assessment: The Class
BCW1 use assessment based on the 2002 and 2016 fish kills placed this segment
in Category 5b. The fish kills were caused by a “pollutant” or was suspected to
be caused by a “pollutant”; therefore, the Class BCW1 use was considered
impaired. Because the source of the pollutant was not identified and/or the
enforcement actions taken against the responsible party have not been resolved
for all the historic fish kills, the Class BCW1 use was placed in Category 5b.
Due to uncertainty regarding the recovery of the aquatic life following the fish
kill, any existing fish kill 5b impairment will remain in Category 5b until
more recent sampling has shown recovery of the aquatic community or the
responsible party has paid restitution for all the historic fish kills. Details
about the 2002 fish kill can be found here: https://programs.iowadnr.gov/fishkill/Events/530
Details
about the 2016 fish kill can be found here: https://programs.iowadnr.gov/fishkill/Events/917 Class HH - No Data