Assessment Summary
This lake is not designated for the Class A1 use. The Class BLW use was assessed (monitored) as "not supported" due to violation of the class BLW criteria based on information from the DNR Fisheries Bureau that suggests poor water transparency due to algae and inorganic turbidity (suspended solids) have led to a poor fishery that suggested an impairment of the aquatic life use. In addition, a fish kill occurred at this lake also suggests a potential impairment of the Class BLW use. The Class HH (fish consumption) use was assessed as "WINOFI" based on fish tissue sampling data. According to DNR’s assessment methodology, the one-time occurrence of a level of mercury above an advisory trigger level does not suggest impairment of the Class HH use. The Iowa DNR/DPH advisory protocol states that two consecutive samplings that show contaminant levels are above the trigger level in edible tissue are needed to justify issuance of an advisory.
Note: A TMDL for algae, turbidity, and pH at Avenue of the Saints Lake was prepared by DNR and approved by EPA in 2019. Because all Section 303(d) impairments identified for the current assessment/listing cycle (algal growth, turbidity, and pH) are addressed by the TMDL, this waterbody is placed in IR Category 4a (impaired; TMDL approved).
Assessment Explanation
Data Sources:
|
Data Source
|
Data Source ID
|
Data Type
|
Data Age
|
Site ID
|
Site
Name
|
Site
Description
|
|
Iowa DNR
|
6
|
WQ
|
CY 2018-2022
|
22090001
|
Avenue
of the Saints Lake
|
|
|
Iowa DNR
|
6
|
FT
|
See Below
|
1280
|
Avenue
of the Saints Lake
|
|
Class BLW - 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
|
|
22090001
|
6
|
Chlorophyll a TSI
|
12 / 4
|
51
|
76
|
70
|
YES
|
Mon
|
Not
|
|
22090001
|
6
|
Secchi TSI
|
12 / 4
|
66
|
83
|
73
|
YES
|
Mon
|
Not
|
|
22090001
|
6
|
Total Phosphorus TSI
|
12 / 4
|
73
|
96
|
82
|
NA
|
NA
|
NA
|
|
22090001
|
6
|
Inorganic suspended solids
|
12 / 4
|
0.6
|
12
|
6.5
|
NA
|
NA
|
NA
|
Class BLW - Binomial 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
|
|
22090001
|
6
|
Dissolved Oxygen
|
12 / 4
|
5.5
|
9.9
|
7.4
|
0
|
NA / NA
|
4
|
NO
|
Mon
|
Full
|
|
22090001
|
6
|
pH
|
12 / 4
|
7.5
|
9.2
|
8.3
|
2
|
NA / NA
|
4
|
NO
|
Mon
|
Full
|
|
22090001
|
6
|
Temperature
|
12 / 4
|
16.6
|
26.2
|
23.2
|
0
|
NA / NA
|
4
|
NO
|
Mon
|
Full
|
- Avenue of the Saints Lake was assessed as "not
supported" for the 2016 assessment/listing cycle due to frequent
violations of the state Class BLW criterion for pH. Based on DNR’s assessment
methodology the current assessment/listing cycles must have fewer violations of
the criterion based on the minimum required by on the 10% Rule to propose
delisting. There were less than 10% of the samples exceeding the
single-sample maximum pH criterion for the 2024 assessment/listing cycle.
Therefore, the (4a) impairment for pH is suggested for removal from category 4a
for the 2024 assessment/listing cycle.
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 Concentration = 75th Percentile
|
Assessment Type
|
Support Level
|
|
22090001
|
6
|
3
|
13.69
|
68%
|
1.00
|
4%
|
NO
|
Evaluated
|
NA
|
Class BLW - 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
|
|
22090001
|
6
|
Ammonia
|
12 / 4
|
0.699
|
0.23
|
0.13
|
0 / 0
|
NO
|
Mon
|
Full
|
Class BLW - Fish
Kill:
The Class BLW
use was assessed (evaluated) as “WINOFI” due to fish kill that occurred in March
of 2021. Because the cause of the fish kill was not identified, or the fish
kill was attributed to a non-pollutant cause (e.g., winterkill), the assessment
type is “evaluated.” Segments assessed using “evaluated” assessments are placed
in Category 3b and are added to the state list of waters in need of further
investigation. If no additional fish kills are reported in the segment for a 5-year period (2026), the Category will be changed from 3b to 3a (water not assessed).
Details about
the 2021 fish kill can be found here: https://programs.iowadnr.gov/fishkill/events/1028
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)
|
|
1280
|
fillet
|
2013
|
common carp
|
4
|
41.1
|
0.1
|
<0.2
|
<0.6
|
|
1280
|
tissue plug
|
2013
|
largemouth bass
|
4
|
42.7
|
0.786
|
|
|
|
Support Level
|
WINOFI
|
The Class HH (fish consumption) use was potentially
impaired due to single sample above an advisory threshold. Further monitoring
is needed to confirm impairment.
|
