Pecks Creek IA 01-TRK-168
mouth (S1 T91N R3W Clayton Co.) to south line of S15 T91N R3W Clayton Co.
- Cycle
- 2020
- Release Status
- Final
- Overall IR
- 5 - Water is impaired or threatened and a TMDL is needed.
- Trend
- Unknown
- Created
- 8/19/2020 2:33:48 PM
- Updated
- 10/15/2020 7:31:51 AM
The presumptive Class A1 use remains assessed as “partially supported” due to levels of indicator bacteria (E. coli) that violated state water quality criteria. The presumptive Class A2 use remains assessed as “fully supported” based on the same indicator bacteria monitoring data. The Class BCW1 use remains assessed as “partially supported” based on biological sampling data. 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
2012-2014 11220012 Peck
Creek near Osterdock Site
326 Iowa
DNR 6 BIO See
Below 570 Peck
Creek Osterdock
(PeCr2) Iowa
DNR 6 BIO See
Below 861 Peck
Creek Osterdock
(PeCr3) Presumptive
Class A1 - Indicator Bacteria: Site ID Data Source ID # Samples / # Years 2012 Geomean 2013 Geomean 2014 Geomean Annual Geomean Violation # Violations % Violations Significantly >10% Violations Assessment Type Support Level 11220012 6 23 / 3 500 148 164 Yes 10 43% Yes Evaluated Partial Presumptive Class A2 -
Indicator Bacteria: Site ID Data Source ID # Samples / # Years 2012 Geomean 2013 Geomean 2014 Geomean Annual Geomean Violation # Violations % Violations Significantly >10% Violations Assessment Type Support Level 11220012 6 23 / 3 500 148 164 No 2 9% No Evaluated Full Class A - pH: Site
ID Data
Source ID #
Samples / # Years Maximum
Value Mean
Value Median
Value #
Violations %
Violations Significantly
>10% Violations Assessment
Type Support
Level 11220012 6 14
/ 2 8.9 8.43 8.4 No 0 No Evaluated Full Class BCW1 - 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 11220012 6 Ammonia 15
/ 2 0.21 0.07 0.05 0
/ 0 0%
/ 0% No Evaluated Full 11220012 6 Chloride 14
/ 2 33 32.43 33 0
/ 0 0%
/ 0% No Evaluated Full 11220012 6 Dissolved
Oxygen 22
/ 3 12 8.9 9 NA
/ 2 NA
/ 9% No Evaluated Full 11220012 6 pH 22
/ 3 9 8.37 9.36 0
/ NA 0%
/ NA No Evaluated Full 11220012 19 Temperature 23 / 3 21.1 14.8 16.3 0
/ 2 0%
/ 9% No Evaluated Full 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 861 9/7/11 10 52b MS/CW Hess 49 NA 60 Fail 570 9/6/11 10 52b MS/CW Hess 47 NA 60 Fail 861 7/26/11 9 52b MS/CW Hess 45 NA 60 Fail 570 7/25/11 9 52b MS/CW Hess 44 NA 60 Fail Overall
Assessment:
Community Assessment Type Assessment Result Support Level Earned IR Category Actual IR Category Reason Benthic Macroinvertebrates Evaluated Fail (0/4) Partial 3bc 5bt Assessment
is evaluated because the samples were collected in single year and not
collected in the last five years. Class BCW1: Continuous Monitoring The continuous dissolved oxygen (DO) and temperature monitoring at two stream locations in 2011 for the DNR/SHL coldwater stream sampling project do suggest impairment of Class BCW1 aquatic life uses. The lowest DO concentration recorded in 48 days of continuous monitoring was 5.5 mg/L. The daily DO minimum concentration failed to meet the 24-hour DO criterion (5 mg/L) in 0 of 48 days. The percentage exceeding (0%) was less than (passing) the 10% impairment threshold used to assess conventional water quality parameters. The associated statistical analysis confidence level was high (>90%). In contrast, the 16-hour DO criterion (7 mg/L) was exceeded in 22 of 48 days. The percentage exceeding (46%) was greater than (failing) the 10% threshold with high statistical confidence (>90%). The maximum stream temperature recorded during the sensor deployment period was 28.3 degrees (C). The BCW1 temperature criterion of 20 (C) was exceeded in 36 of 48 days. The percentage exceeding (75%) 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. 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.