Assessment Summary
The Class A1 uses are assessed (monitored) as “partially supported” due to levels of indicator bacteria that exceed Iowa’s water quality standard and due to poor water transparency caused by algae blooms. The Class BLW uses are assessed (evaluated) as “partially supported” due to a fish kill and due to cyanobacteria bloom. Fish consumption uses are assessed (evaluated) as "fully supported" based on results of fish tissue (RAFT) sampling in 2007 and 2009.
Note: A TMDL for nutrients and siltation at Lake MacBride was prepared by DNR and approved by EPA in 2005.Because however, the Section 303(d) impairment due to indicator bacteria and Do violations at this lake were not addressed in the TMDL, this lake is placed in IR Category 5a (impaired; TMDL required).
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 2016-2018
|
21520001
|
Lake Macbride Beach (Lake Macbride State
Park)
|
|
|
Iowa DNR
|
6
|
WQ
|
CY 2014-2018
|
22520001
|
Lake Macbride (maximum water depth)
|
|
|
Iowa DNR
|
|
FT
|
See Below
|
81
|
Lake Macbride
|
|
Class A1 -
Indicator Bacteria:
|
Site ID
|
Data Source ID
|
# Samples / # Years
|
2016 Geometric Mean
|
2017 Geometric Mean
|
2018 Geometric Mean
|
Annual Geometric Mean Violation
|
# Violations
|
% Violations
|
Significantly >10% Violations
|
Assessment Type
|
Support Level
|
|
21520001
|
6
|
42 / 3
|
43.99
|
103.12
|
262.83
|
YES
|
19
|
45%
|
YES
|
Monitored
|
Partial
|
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
|
|
22520001
|
6
|
16 / 5
|
9.1
|
8.5
|
8.4
|
1
|
6%
|
NO
|
Monitored
|
Full
|
Class A1 - Lake
TSI's
|
Site ID
|
Data Source ID
|
Parameter Name
|
# Samples / # Years
|
Minimum Value
|
Maximum Value
|
Median Value
|
Median TSI Violation
|
Assessment Type
|
Support Level
|
|
22520001
|
6
|
Chlorophyll a TSI
|
16 / 5
|
36
|
80
|
64
|
NO
|
Monitored
|
Full
|
|
22520001
|
6
|
Secchi TSI
|
16 / 5
|
44
|
70
|
63
|
NO
|
Monitored
|
Full
|
|
22520001
|
6
|
Total Phosphorus TSI
|
16 / 5
|
53
|
88
|
64
|
NA
|
NA
|
NA
|
|
22520001
|
6
|
Inorganic suspended solids
|
16 / 5
|
0.4
|
5
|
1.6
|
NA
|
NA
|
NA
|
Although the index value for Chlorophyll a is below the impairment trigger of 65 for this assessment cycle, Lake Macbride was listed as partially supporting its Class A1 uses due to aesthetically objectionable conditions. Based on DNR's methodology, the median TSI value for Chlorophyll a must be 63 or less for two consecutive assessment/listing cycles before a lake can be removed from the state's Section 303(d) list (IR Category 5). Therefore, Lake Macbride will remain listed as "not supported" for the 2020 assessment/listing cycle.
Class BLW -
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
|
|
22520001
|
6
|
Ammonia
|
16 / 5
|
0.12
|
0.04
|
0.04
|
0 / 0
|
0% / 0%
|
NO
|
Monitored
|
Full
|
|
22520001
|
6
|
Dissolved oxygen
|
16 / 5
|
17.9
|
8.03
|
7.39
|
NA / 1
|
NA / 6%
|
NO
|
Monitored
|
Full
|
|
22520001
|
6
|
pH
|
16 / 5
|
9.1
|
8.5
|
8.4
|
1 / NA
|
6% / NA
|
NO
|
Monitored
|
Full
|
|
22520001
|
6
|
Temperature
|
16 / 5
|
27.2
|
23.48
|
22.91
|
0 / 0
|
0% / 0%
|
NO
|
Monitored
|
Full
|
Class BLW -
Lake Planktonic Cyanobacteria:
|
Site ID
|
Data Source ID
|
# Samples
|
Maximum Cyanobacteria Wet Mass
|
Maximum Cyanobacteria % Composition
|
Median Cyanobacteria Wet Mass
|
Median Cyanobacteria % Composition
|
Median Cyanobacteria Wet Mass = 75th
Percentile
|
Assessment Type
|
Support Level
|
|
22520001
|
6
|
11
|
707.757
|
98.9 %
|
24.693
|
85 %
|
YES
|
Evaluated
|
3b
|
Class BLW - Fish Kill:
The Class BLW uses are assessed (evaluated) as “partially supported” due to a fish kill that on June 7, 2011. According to DNR's assessment methodology, the occurrence of a single pollutant-caused fish kill, or a fish kill of unknown origin, on a waterbody or waterbody reach during the most recent assessment period indicates a severe stress to the aquatic community and suggests that the aquatic life uses should be assessed as “impaired.” If a cause of the kill was not identified during the DNR investigation, or if the kill was attributed to non-pollutant causes (e.g., winterkill), the assessment type will be considered “evaluated” and will be placed in IR subcategories 3b and will be added to the state list of waters in need of further investigation.
Details about the 2013 fish kill can be found here: https://programs.iowadnr.gov/fishkill/Events/838
Class HH-F – Fish
Tissue Sampling:
|
Site ID
|
Date
|
Species Name
|
Biopart
|
# in sample
|
chlordane result
|
chlordane violation?
|
PCBs result
|
PCBs violation?
|
Hg result
|
Hg violation?
|
Assessment Type
|
Support Level
|
|
81
|
7/23/09
|
snapping turtle
|
shoulder
|
3
|
<0.03
|
No
|
<0.09
|
No
|
0.113
|
No
|
Evaluated
|
Full
|
|
81
|
7/27/07
|
channel catfish
|
fillet
|
5
|
<0.03
|
No
|
<0.09
|
No
|
0.179
|
No
|
Evaluated
|
Full
|
|
81
|
7/27/07
|
largemouth bass
|
fillet
|
5
|
|
|
|
|
0.0627
|
No
|
Evaluated
|
Full
|
