Avenue Of The Saints Lake IA 02-SHL-1790

Bremer Co. approximately 2 miles E of Shell Rock in S7 T91N R14W

Open Data Collection Period Modal

For purposes of developing stream/river water quality assessments for integrated reporting, three years of water quality data are typically used for both conventional pollutant parameters (e.g., indicator bacteria) and the less frequently monitored toxic parameters (e.g., toxic metals). Since the 2004 IR cycle, DNR has used a three-year data gathering period for streams, rivers, and beaches. For most assessments, the use of three years of data increases the number of samples upon which the decision on use support is based and helps address the problem of weather-related year-to-year fluctuations in water quality.

Due to the lower sampling frequency in Iowa’s ambient lake, biological, fish kill, and fish tissue monitoring programs, five years of data are used for developing IR assessments and for identifying Section 303(d) listings.

Data Type	Data Timeframe
Beach Sampling Data	CY 2018 - 2020
Stream/River Water Quality Data	CY 2018 - 2020
Lake Water Quality Data	CY 2016 - 2020
Biological Sampling Data	CY 2016 - 2020*
Fish Kill Data	CY 2016 - 2020
Fish Tissue Sampling Data	CY 2016 - 2020
Continuous Dissolved Oxygen Sampling Data	CY 2016 - 2020
*Biological sites sampled in both 2015 and 2019 were also assessed.

Open Segment Map
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Cycle: 2022
Release Status: Final
Overall IR: 4 - Water is impaired or threatened and a TMDL has been completed or is not needed.
Trophic: Hypereutrophic
Trend: Stable
Created: 1/5/2022 7:20:59 AM
Updated: 2/1/2022 7:26:49 AM

Use Support

Class BLW

Aquatic Life - Lakes and wetlands

Not Supported

Support Level

Not Supported

Impairment Code

4a - Pollutant-caused impairment. TMDL has been completed.

Cause Magnitude

Moderate

Status

Continuing

Source

Natural: Internal Nutrient Recycling (Primarily Lakes)

Source Confidence

Low

Cycle Added

2016

Impairment Rationale

Adverse impacts on plant/animal communities

Data Source

TMDL monitoring: Iowa DNR

Algal Growth: Chlorophyll a

Support Level

Not Supported

Impairment Code

4a - Pollutant-caused impairment. TMDL has been completed.

Cause Magnitude

Moderate

Status

Continuing

Source

Agriculture

Source Confidence

Moderate

Cycle Added

2004

Impairment Rationale

Adverse impacts on plant/animal communities

Data Source

TMDL monitoring: Iowa DNR

Turbidity

Support Level

Not Supported

Impairment Code

4a - Pollutant-caused impairment. TMDL has been completed.

Cause Magnitude

Moderate

Status

Continuing

Source

Hydromodification: Erosion and Sedimentation

Source Confidence

Moderate

Cycle Added

2004

Impairment Rationale

Adverse impacts on plant/animal communities

Data Source

TMDL monitoring: Iowa DNR

Fish Kill: Due To Natural Causes

Support Level

Further Investigation Needed

Impairment Code

3b - Use potentially impaired based on an evaluated assessment.

Cause Magnitude

Slight

Status

Continuing

Source

Natural: Natural Sources

Source Confidence

Low

Cycle Added

2016

Impairment Rationale

Potential Impairment

Data Source

Fish kill investigation: Iowa DNR

Class HH

Human Health -

WINOFI

Metals: Mercury

Support Level

Further Investigation Needed

Impairment Code

3b - Use potentially impaired based on an evaluated assessment.

Cause Magnitude

Slight

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

N/A

Cycle Added

2016

Impairment Rationale

Potential fish consumption advisory; additional sampling needed

Data Source

Fish contaminant monitoring: Iowa DNR

Impairment Delistings

No delistings for this assessment cycle.

Documentation

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 for pH. Information from the DNR Fisheries Bureau 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. Additional monitoring will be conducted to better determine levels of mercury in the edible portions of fish in this lake. 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 2016-2019	22090001	Avenue of the Saints Lake	Lake Deep Point
Iowa DNR		FT	See Below	282	Avenue of the Saints Lake

Class BLW - 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	44	76	64	NO	Monitored	Full
22090001	6	Secchi TSI	12 / 4	66	77	73	YES	Monitored	Not
22090001	6	Total Phosphorus TSI	12 / 4	69	96	80	NA	NA	NA
22090001	6	Inorganic suspended solids	12 / 4	0.6	11	6.5	NA	NA	NA

Class BLW - 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
22090001	6	Ammonia	12 / 4	0.0003	0.6986	0.15	NA	0 / 0	4	NO	Monitored	Full
22090001	6	Dissolved Oxygen	12 / 4	5.5	11	7.9	0	NA / NA	4	NO	Monitored	Full
22090001	6	pH	12 / 4	7.5	10.1	8.6	4	NA / NA	4	YES	Monitored	Not
22090001	6	Temperature	12 / 4	19.2	26.5	23.7	0	NA / NA	4	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 Concentration = 75th Percentile	Assessment Type	Support Level
22090001	6	6	643.91	100.0%	45.67	93.1%	YES	Evaluated	3b

Class BLW - Fish Kill:

The Class BLW use was assessed (evaluated) as “WINOFI” due to fish kill that occurred in May of 2015. 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 10 year period, the Category will be changed from 3b to 3a (water not assessed).

Details about the 2015 fish kill can be found here: https://programs.iowadnr.gov/fishkill/Events/902

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)
282	fillet	2013	common carp	4	41.1	0.1	<0.2	<0.6
282	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.

Monitoring and Methods

Assessment Key Dates

6/6/2016

Non-fixed Monitoring Start Date

9/25/2019

Non-fixed Monitoring End Date

8/29/2013

Fish Tissue Monitoring

9/25/2019

TMDL Completed

Methods

120

Surveys of fish and game biologists/other professionals

222

Non-fixed-station monitoring (conventional during key seasons and flows)

260

Fish tissue analysis

340

Primary producer surveys (phytoplankton/periphyton/macrophyton)