Assessment Summary
The Class A1 primary contact recreation use remains assessed as "not supported" due to 2014-2016 violations of the state criteria for indicator bacteria. The Class BWW1 aquatic life use was assessed as “partially supported” based on 2003, 2016, and 2018 biological sampling data. The Class HH (fish consumption) use remains assessed as “partially supported” due to detectable levels of DDE and dieldrin in 2013 and 2014. All other designated uses were "not assessed".
Assessment Explanation
Sources of Data:
|
Data Source
|
Data Source ID
|
Data Type
|
Data Age
|
Site ID
|
Site Name
|
Site Description
|
|
Iowa DNR
|
6
|
WQ
|
CY 2014-2016, CY
2016-2018
|
10360003
|
Nishnabotna River
near Hamburg
|
|
|
Iowa DNR
|
6
|
BIO
|
See Below
|
388
|
Nishnabotna River
|
Hamburg – REMAP #43
|
|
Iowa DNR
|
6
|
BIO
|
See Below
|
928
|
Nishnabotna River
|
Hamburg
|
|
Iowa DNR
|
6
|
FT
|
See Below
|
111
|
Nishnabotna River
|
At Hamburg
|
Class A1 - Indicator Bacteria:
|
Site ID
|
Data Source ID
|
# Samples / # Years
|
2014 Geometric Mean
|
2015 Geometric Mean
|
2016 Geometric Mean
|
Annual Geometric Mean
Violation
|
# Violations
|
% Violations
|
Significantly >10%
Violations
|
Assessment Type
|
Support Level
|
|
10360003
|
6
|
23 / 3
|
900
|
296
|
1734
|
Yes
|
12
|
52%
|
Yes
|
Evaluated
|
Not
|
Class A1 - pH:
|
Site ID
|
Data Source ID
|
# Samples / # Years
|
Maximum Value
|
Mean Value
|
Median Value
|
# Violations
|
% Violations
|
Significantly >10%
Violations
|
Assessment Type
|
Support Level
|
|
10360003
|
6
|
36 / 3
|
8.8
|
8.1
|
8.2
|
0
|
0%
|
No
|
Monitored
|
Full
|
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
|
|
10360003
|
6
|
Ammonia
|
36 / 3
|
0.34
|
0.04
|
0.02
|
0 / 0
|
0% / 0%
|
No
|
Monitored
|
Full
|
|
10360003
|
6
|
Chloride
|
36 / 3
|
17
|
13
|
13
|
0 / 0
|
0% / 0%
|
No
|
Monitored
|
Full
|
|
10360003
|
6
|
Dissolved oxygen
|
36 / 3
|
13.5
|
9.9
|
9.9
|
NA / 0
|
NA / 0%
|
No
|
Monitored
|
Full
|
|
10360003
|
6
|
pH
|
36 / 3
|
8.8
|
8.1
|
8.2
|
0 / NA
|
0% / NA
|
No
|
Monitored
|
Full
|
|
10360003
|
6
|
Sulfate
|
36 / 3
|
31
|
21
|
22
|
0 / NA
|
0% / NA
|
No
|
Monitored
|
Full
|
|
10360003
|
6
|
Temperature
|
36 / 3
|
28.2
|
14.2
|
13.6
|
0 / 0
|
0% / 0%
|
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
|
% Acute/ Chronic
Violations
|
>1 Acute / Chronic
Violation
|
Assessment Type
|
Support Level
|
|
10360003
|
6
|
Aluminum
|
9 / 2
|
23
|
6.19
|
3.6
|
0 / 0
|
0% / 0%
|
No
|
Evaluated
|
Full
|
|
10360003
|
6
|
Arsenic
|
9 / 2
|
3.6
|
2.6
|
2.4
|
0 / 0
|
0% / 0%
|
No
|
Evaluated
|
Full
|
|
10360003
|
6
|
Cadmium
|
9 / 2
|
0.025
|
0.025
|
0.025
|
0 / 0
|
0% / 0%
|
No
|
Evaluated
|
Full
|
|
10360003
|
6
|
Chromium
|
9 / 2
|
0.92
|
0.52
|
0.57
|
0 / 0
|
0% / 0%
|
No
|
Evaluated
|
Full
|
|
10360003
|
6
|
Copper
|
9 / 2
|
1.8
|
0.98
|
0.78
|
0 / 0
|
0% / 0%
|
No
|
Evaluated
|
Full
|
|
10360003
|
6
|
Lead
|
9 / 2
|
0.23
|
0.095
|
0.07
|
0 / 0
|
0% / 0%
|
No
|
Evaluated
|
Full
|
|
10360003
|
6
|
Nickel
|
9 / 2
|
3.7
|
2.3
|
2
|
0 / 0
|
0% / 0%
|
No
|
Evaluated
|
Full
|
|
10360003
|
6
|
Selenium
|
9 / 2
|
3.9
|
2.9
|
2.7
|
0 / 0
|
0% / 0%
|
No
|
Evaluated
|
Full
|
|
10360003
|
6
|
Zinc
|
9 / 2
|
4.1
|
1.39
|
0.83
|
0 / 0
|
0% / 0%
|
No
|
Evaluated
|
Full
|
Class
BWW1 - Biological Sampling:
Benthic
Macroinvertebrates:
|
BioNet Site ID
|
Date
|
Drainage Area (mi2)
|
Ecoregion
|
Major Drainage/Thermal
|
BM Sample Gear
|
BMIBI score
|
BMIBI Class
|
47m BMIBI BIT
|
BMIBI Pass/ Fail
|
|
928
|
8/13/18
|
2807
|
47m
|
MO/WW
|
Float ArtSub
|
45
|
Fair
|
54
|
Fail
|
|
928
|
9/6/16
|
2807
|
47m
|
MO/WW
|
Float ArtSub
|
46
|
Fair
|
54
|
Fail
|
Fish:
|
BioNet Site ID
|
Date
|
Drainage Area (mi2)
|
Ecoregion
|
Major Drainage/Thermal
|
Riffle Stream?
|
FIBI score
|
FIBI Class
|
47m FIBI BIT
|
FIBI Pass/ Fail
|
|
388
|
8/12/03
|
2818
|
47m
|
MO/WW
|
NA
|
5
|
Poor
|
31
|
Fail
|
Overall:
|
Community
|
Assessment Type
|
Assessment Result
|
Support Level
|
Earned IR Category
|
Actual IR Category
|
Reason
|
|
Benthic
Macroinvertebrates
|
Evaluated
|
Fail (0/2)
|
Partial
|
|
|
|
|
Fish
|
Evaluated
|
Fail (0/1)
|
Not
|
|
|
|
|
Overall
|
Evaluated
|
Fail
|
Partial
|
3bu
|
3bu
|
Assessment
is evaluated because the drainage areas of the sites were larger than the
calibrated range.
|
Class
HH – Fish Tissue Sampling:
|
Site ID
|
Date
|
Species Name
|
Biopart
|
# in sample
|
chlordane result
|
chlordane violation (>0.6)?
|
PCBs result
|
PCBs violation (>0.2)?
|
Hg result
|
Hg violation (>0.3)?
|
Assessment Type
|
Support Level
|
|
111
|
8/19/2016
|
common carp
|
whole
|
5
|
0.06
|
No
|
<0.06
|
No
|
<0.05
|
No
|
Monitored
|
Full
|
|
111
|
8/25/2011
|
black crappie
|
plug
|
3
|
|
|
|
|
0.155
|
No
|
Evaluated
|
Full
|
|
111
|
8/25/2011
|
common carp
|
fillet
|
4
|
<0.03
|
No
|
<0.09
|
No
|
0.056
|
No
|
Evaluated
|
Full
|
Class HH-F - Toxic Parameters:
|
Site ID
|
Data Source ID
|
Parameter Name
|
# Samples / # Years
|
Maximum Value
|
Mean Value
|
Median Value
|
Number of Non -
Detects
|
Mean Value >
Criterion or MCL
|
Assessment Type
|
Support Level
|
|
10360003
|
6
|
Cadmium
|
9 / 2
|
0.025
|
0.025
|
0.025
|
9
|
No
|
Evaluated
|
Full
|
|
10360003
|
6
|
Chromium
|
9 / 2
|
0.92
|
0.52
|
0.57
|
0
|
No
|
Evaluated
|
Full
|
|
10360003
|
6
|
Copper
|
9 / 2
|
1.8
|
0.98
|
0.78
|
0
|
No
|
Evaluated
|
Full
|
|
10360003
|
6
|
Nickel
|
9 / 2
|
3.7
|
2.3
|
2
|
0
|
No
|
Evaluated
|
Full
|
|
10360003
|
6
|
Selenium
|
9 / 2
|
3.9
|
2.9
|
2.7
|
0
|
No
|
Evaluated
|
Full
|
|
10360003
|
6
|
Zinc
|
9 / 2
|
4.1
|
1.39
|
0.83
|
0
|
No
|
Evaluated
|
Full
|
Class HH-F –
Historic Assessment:
The results of
USGS monitoring from 2012 and 2014 showed one of the 33 samples (3%) analyzed
for DDE and three of the 33 samples (9%) analyzed for Dieldrin exceeded
criteria. The sample collected on January 16, 2013 at USGS station 6810000
(near Hamburg) had a detectable level of DDE of 0.003 ug/l, thus exceeding the
HH-fish criterion of 0.0022 ug/l. Levels of DDE the remainder of the samples at
this monitoring stations were reported as less than the levels of detection
(0.002 ug/l and 0.005 ug/l). The samples collected on June 10, 2014, July 15,
2014 and September 16, 2014 at USGS station 06810000 (near Hamburg) had
detectable levels of dieldrin of 0.004 ug/l, 0.003 ug/l and 0.003 ug/l
respectively, thus exceeding the HH-fish criterion of 0.00054 ug/l. Levels of
dieldrin the remainder of the samples at this monitoring stations were reported
as less than the level of detection (0.008 ug/l). According to DNR’s
assessment/listing methodology, if the average level of a toxic metal or
pesticide is greater than its respective human health criterion, impairment
("non-support") of the Human Health use is indicated. The number of
samples with detectable levels of DDE and dieldrin at these monitoring stations
(1/33 and 3/33), however, is too few and the method detection level is far too
high (~16 times greater than the HH criterion for dieldrin) to allow
calculation of a meaningful summary statistic (e.g., mean) for DDE and dieldrin
at this monitoring station. Based on sampling that shows detectable levels of
DDE and dieldrin, however, the Human Health designated use will be considered
(evaluated) as “partially supported”.
