Shell Rock River IA 02-SHL-783
from south corporate limit of Shell Rock (S12 T91N R15W Butler Co.) to confluence with Flood Cr. in S27 T93N R16W Butler Co.
- Assessment Cycle
- 2022
- Release Status
- Final
- Data Collection Period
- Overall IR Category
- 5 - Water is impaired or threatened and a TMDL is needed.
- Trend
- Unknown
- Created
- 12/21/2021 3:24:05 PM
- Updated
- 1/25/2022 12:16:26 PM
The presumptive Class A1 use was assessed as "not supported" based on levels of indicator bacteria (E. coli) that exceeded state water quality criteria. The Class BWW1 use was assessed as "fully supported" based on biological sampling data and water quality monitoring data. The Class HH use remains assessed as "not supported" based on fish tissue sampling data and due to a one meal/week mercury consumption advisory for any predator fish in this segment.
Data Sources:
Data Source |
Data Source ID |
Data Type |
Data Age |
Site ID |
Site Name |
Site Description |
Iowa DNR |
6 |
WQ |
CY 2018-2020 |
10120001 |
Shell Rock River at Shell Rock |
|
Iowa DNR |
6 |
BIO |
See Below |
843 |
Shell Rock River |
Shell Rock |
Iowa DNR |
6 |
FT |
See Below |
68 |
Shell Rock River W of Clarksville |
|
Presumptive Class A1 - Indicator Bacteria:
Site ID |
Data Source ID |
# Samples per Year (2018/ 2019/2020) |
2018 Geometric Mean |
2019 Geometric Mean |
2020 Geometric Mean |
Violates Annual Geometric Mean? |
# 2018 SSM violations / SSM Violations needed for impairment |
# 2019 SSM violations / SSM Violations needed for impairment |
# 2020 SSM violations / SSM Violations needed for impairment |
Violates Annual SSM Significantly >10% Rule? |
Assessment Type |
Support Level |
10120001 |
6 |
7/8/8 |
263 |
168 |
51 |
YES |
4 / 3 |
3 / 3 |
1 / 3 |
YES |
Monitored |
Not |
Class A – pH:
Site ID |
Data Source ID |
# Samples / # Years |
Minimum Value |
Maximum Value |
Mean Value |
# Violations |
Violations needed for impairment |
Violates Significantly >10% Rule? |
Assessment Type |
Support Level |
10120001 |
6 |
36 / 3 |
7.2 |
8.5 |
8.1 |
0 |
7 |
NO |
Monitored |
Full |
Class BWW1 - Conventional Parameters:
Site ID |
Data Source ID |
Parameter Name |
# Samples / # Years |
Minimum Value |
Maximum Value |
Mean Value |
# Violations |
# Acute / Chronic Violations |
Violations needed for impairment |
Violates Significantly >10% Rule? |
Assessment Type |
Support Level |
10120001 |
6 |
Ammonia |
36 / 3 |
0.02 |
0.77 |
0.07 |
NA |
0 / 0 |
7 |
NO |
Monitored |
Full |
10120001 |
6 |
Chloride |
36 / 3 |
6.6 |
29 |
18.2 |
NA |
0 / 0 |
7 |
NO |
Monitored |
Full |
10120001 |
6 |
Dissolved Oxygen |
36 / 3 |
6.4 |
14 |
10.9 |
0 |
NA / NA |
7 |
NO |
Monitored |
Full |
10120001 |
6 |
pH |
36 / 3 |
7.2 |
8.5 |
8.1 |
0 |
NA / NA |
7 |
NO |
Monitored |
Full |
10120001 |
6 |
Sulfate |
36 / 3 |
5 |
56 |
30 |
0 |
NA / NA |
7 |
NO |
Monitored |
Full |
10120001 |
6 |
Temperature |
36 / 3 |
0.2 |
25.3 |
11 |
0 |
NA / NA |
7 |
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 |
>1 Acute / Chronic Violation |
Assessment Type |
Support Level |
10120001 |
6 |
Aluminum |
14 / 3 |
1.8 |
0.4 |
0.1 |
0 / 0 |
NO |
Monitored |
Full |
10120001 |
6 |
Arsenic |
13 / 3 |
2 |
1.21 |
1.1 |
0 / 0 |
NO |
Monitored |
Full |
10120001 |
6 |
Cadmium |
13 / 3 |
0.06 |
0.03 |
0.02 |
0 / 0 |
NO |
Monitored |
Full |
10120001 |
6 |
Chromium |
13 / 3 |
1.2 |
0.9 |
0.9 |
0 / 0 |
NO |
Monitored |
Full |
10120001 |
6 |
Lead |
13 / 3 |
0.19 |
0.09 |
0.09 |
0 / 0 |
NO |
Monitored |
Full |
10120001 |
6 |
Nickel |
13 / 3 |
3.7 |
2.8 |
2.9 |
0 / 0 |
NO |
Monitored |
Full |
10120001 |
6 |
Silver |
13 / 3 |
0.025 |
0.025 |
0.025 |
0 / 0 |
NO |
Monitored |
Full |
10120001 |
6 |
Zinc |
13 / 3 |
2.6 |
1.9 |
1.8 |
0 / 0 |
NO |
Monitored |
Full |
Class BWW1 - Biological Sampling:
Benthic Macroinvertebrates:
Site ID |
Date |
Drainage Area (mi2) |
Ecoregion |
Major Drainage |
BM Sample Gear |
BMIBI score |
BMIBI Class |
47c BMIBI BIT |
BMIBI Pass/ Fail |
843 |
8/23/19 |
1730 |
47c |
MS |
Hess |
72 |
Good |
70 |
Pass |
843 |
8/20/19 |
1730 |
47c |
MS |
Hess |
58 |
Good |
70 |
Fail |
843 |
8/15/16 |
1730 |
47c |
MS |
Hess |
81 |
Excellent |
70 |
Pass |
Overall:
Community |
Assessment Type |
Assessment Result |
Support Level |
IR Category |
Reason |
Benthic Macroinvertebrates |
Evaluated |
Pass (2/3) |
Full |
Assessment was evaluated because the drainage area of the site used for |
|
Overall |
Evaluated |
Pass |
Full |
1 |
the assessment was greater than the calibrated range. |
Class BWW1 - Continuous DO Monitoring:
Site ID |
Data Source ID |
# Days Monitoring (2016/2017/2018/ 2019/2020) |
DO Criteria Type |
# 2016 violations / Violations needed for impairment |
# 2017 violations / Violations needed for impairment |
# 2018 violations / Violations needed for impairment |
# 2019 violations / Violations needed for impairment |
# 2020 violations / Violations needed for impairment |
Violates Annual Significantly >10% Rule? |
Assessment Type |
Support Level |
|
|
|
24 hr |
1/6 |
NA |
NA |
NA |
NA |
No |
|
|
843 |
6 |
29/0/0/0/0 |
16 hr |
0/6 |
NA |
NA |
NA |
NA |
No |
Evaluated |
Full |
Class HH - Fish
Tissue Sampling:
Site ID |
Biopart |
Year |
Species |
# in sample / # of samples |
Avg Length (cm) |
(Avg) Hg (ppm) |
Chlordane (ppm) |
Sum PCBs (ppm) |
68 |
fillet |
2011 |
common carp |
5 |
49.5 |
0.206 |
0.03 |
0.09 |
68 |
tissue plug |
2012 |
walleye |
3 |
40.0 |
0.285 |
|
|
68 |
tissue plug |
2011 |
walleye |
4 |
47.2 |
0.753 |
|
|
Support Level |
Not |
A one meal/week mercury consumption advisory for any predator fish exists on this segment. Based on IR Methodology, the Class HH (fish consumption) use was assessed as “not supported.” |