2024 assessment for Lake Of Three Fires

Lake Of Three Fires IA 05-PLA-1476

Taylor County S12T68NR34W 2 mi NNE of Bedford.

2024
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 2020 - 2022
Stream/River Water Quality Data	CY 2020 - 2022
Lake Water Quality Data	CY 2018 - 2022
Biological Sampling Data	CY 2018 - 2022*
Fish Kill Data	CY 2018 - 2022
Fish Tissue Sampling Data	CY 2018 - 2022
Continuous Dissolved Oxygen Sampling Data	CY 2018 - 2022
*Biological sites sampled in both 2017 and 2021 were also assessed.

Open Segment Map
View assessment methodology in new window

Overall IR

4 - Water is impaired or threatened and a TMDL has been completed or is not needed.

Trophic

Eutrophic

Trend

Stable

Created

11/1/2023 8:13:25 AM by

Updated

2/5/2024 2:41:31 PM by

Use Support

Class A1

Recreation - Primary contact

Not Supported

Turbidity

Support Level

Not Supported

Impairment Code

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

Cause Magnitude

Moderate

303(d) Listing Status

Continuing

Source

Agriculture

Source Confidence

Moderate

Cycle Added

2004

Impairment Rationale

Narrative criteria violation: aesthetically objectionable conditions

Data Source

Ambient monitoring: Iowa DNR-lakes

Algal Growth: Chlorophyll a

Support Level

Not Supported

Impairment Code

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

Cause Magnitude

Moderate

303(d) Listing Status

Continuing

Source

Agriculture

Source Confidence

Moderate

Cycle Added

2014

Impairment Rationale

Narrative criteria violation: aesthetically objectionable conditions

Data Source

Ambient monitoring: Iowa DNR-lakes

Bacteria: Indicator Bacteria- E. coli

Support Level

Not Supported

Impairment Code

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

Cause Magnitude

Slight

303(d) Listing Status

New

Source

Unknown: Source Unknown

Source Confidence

Low

Cycle Added

2024

Impairment Rationale

Single-sample maximum criterion exceeded in significantly > 10% of samples

Data Source

Beach monitoring: Iowa DNR WQMA

Class BLW

Aquatic Life - Lakes and wetlands

WINOFI

Algal Growth: Cyanobacteria

Support Level

Further Investigation Needed

Impairment Code

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

Cause Magnitude

Slight

303(d) Listing Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

N/A

Cycle Added

2020

Impairment Rationale

Adverse impacts on plant/animal communities

Data Source

Ambient monitoring: Iowa DNR-lakes

Class C

Drinking Water -

Fully Supported

Class HH

Human Health -

Fully Supported

303(d) Delistings for this Cycle

Cycle Added	Class	Cause	Data Source	Rationale
2018	Class A1	pH	Ambient monitoring: Iowa DNR-lakes	New data: WQ improvement (chemical / physical / bacterial)
2016	Class BLW	Organic Enrichment: Low Dissolved Oxygen	Ambient monitoring: Iowa DNR-lakes	New data: WQ improvement (chemical / physical / bacterial)
2018	Class BLW	pH	Ambient monitoring: Iowa DNR-lakes	New data: WQ improvement (chemical / physical / bacterial)
2022	Class C	pH	Ambient monitoring: Iowa DNR-lakes	New data: WQ improvement (chemical / physical / bacterial)

Documentation

Assessment Summary

The Class A1 use was assessed (monitored) as “not supported” due to aesthetically objectionable conditions caused by turbidity, aesthetically objectionable conditions caused by algae blooms, and due to levels of indicator bacteria that exceed Iowa’s water quality standard. The Class BLW use was assessed (evaluated) as “WINOFI” due to cyanobacteria blooms. The Class C use was assessed (monitored) as “fully supported." The Class HH (fish consumption) use was assessed (monitored) as “fully supported” based on fish tissue sampling data. Note: A TMDL for impacts of siltation and nutrients at Lake of Three Fires was prepared by DNR and approved by EPA in 2002. Additionally, a TMDL for indicator bacteria at Lake of Three Fires was prepared by DNR and approved by EPA in 2010. Because not all Section 303(d) impairments identified for the current assessment/listing cycle (dissolved oxygen and pH) are addressed in the two TMDLs, this lake is placed into IR Category 5a (TMDL needed.)

Assessment Explanation

Data Sources:

Data Source	Data Source ID	Data Type	Data Age	Site ID	Site Name	Site Description
Iowa DNR	6	WQ	CY 2020-2022	21870001	Lake of Three Fires Beach
Iowa DNR	6	WQ	CY 2018-2022	22870001	Lake of Three Fires Max Depth
Iowa DNR	6	FT	See Below	1156	Lake of Three Fires	Near Bedford

Class A1 - Indicator Bacteria:

Site ID

Data Source ID

# Samples per Year (2020/ 2021/2022)

2020 Geometric Mean

2021 Geometric Mean

2022 Geometric Mean

Violates Annual Geometric Mean?

# 2020 SSM violations / SSM Violations needed for impairment

# 2021 SSM violations / SSM Violations needed for impairment

# 2022 SSM violations / SSM Violations needed for impairment

Violates Annual SSM Significantly >10% Rule?

Assessment Type

Support Level

21870001

15/14/15

2 / 4

4 / 4

YES

Mon

Not

Class A1 - 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
22870001	6	12 / 4	7.3	9.3	8.4	1	4	NO	Mon	Full

Lake of Three Fires was assessed as "not supported" for the 2018 assessment/listing cycle due to frequent violations of the state Class A1 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 the 10% Rule to propose delisting pH. There were less than 10% of the samples exceeding the single-sample maximum criterion for the 2024 assessment/listing cycle. Therefore, the impairment for pH is suggested for delisting for the 2024 assessment/listing cycle.

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
22870001	6	Chlorophyll a TSI	12 / 4	35	80	68	YES	Mon	Not
22870001	6	Secchi TSI	12 / 4	62	74	68	YES	Mon	Not
22870001	6	Total Phosphorus TSI	12 / 4	64	78	69	NA	NA	NA
22870001	6	Inorganic suspended solids	12 / 4	0.6	9	5.5	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
22870001	6	Dissolved Oxygen	12 / 4	3.1	12.5	7.1	3	NA / NA	4	NO	Mon	Full
22870001	6	pH	12 / 4	7.3	9.3	8.4	1	NA / NA	4	NO	Mon	Full
22870001	6	Temperature	12 / 4	16.2	28.4	24.2	0	NA / NA	4	NO	Mon	Full

Lake of Three Fires was assessed as "not supported" for the 2018 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 the 10% Rule to propose delisting pH. There were less than 10% of the samples exceeding the single-sample maximum criterion for the 2024 assessment/listing cycle. Therefore, the impairment for pH is suggested for delisting for the 2024 assessment/listing cycle.
Lake of Three Fires was assessed as "not supported" for the 2016 assessment/listing cycle based on Dissolved Oxygen. Based on DNR’s assessment methodology the current assessment/listing cycles must have fewer violations of the criterion based on the minimum required by the 10% Rule to propose delisting. There were less than 10% of the samples exceeding the single-sample maximum criterion for the current assessment listing cycle. Therefore, the impairment for Dissolved Oxygen is suggested for delisting 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
22870001	6	4	269.644076	100%	28.44882978	86%	YES	Evaluated	3b

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
22870001	6	Ammonia	12 / 4	0.128	0.05	0.04	0 / 0	NO	Mon	Full

Class C - Binomial Parameters:

Site ID	Data Source ID	Parameter Name	# Samples / # Years	Minimum Value	Maximum Value	Mean Value	Median Value	# Violations	Violates Significantly >10% Rule?	Assessment Type	Support Level
22870001	6	Inorganic nitrogen (nitrate and nitrite)	11 / 4	0.02	1.12	0.31	0.15	0	NO	Mon	Full
22870001	6	pH	12 / 4	7.3	9.3	8.4	8.6	1	NO	Mon	Full

Lake of Three Fires was assessed as "not supported" for the 2018 assessment/listing cycle due to frequent violations of the state Class C 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 the 10% Rule to propose delisting pH. There were less than 10% of the samples exceeding the single-sample maximum criterion for the 2024 assessment/listing cycle. Therefore, the impairment for pH is suggested for delisting for the 2024 assessment/listing cycle.

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)
1156	tissue plug	2019	largemouth bass	10	32.6	0.196
1156	tissue plug	2017	largemouth bass	3	41.9	0.28
Support Level	Full

Monitoring and Methods

Assessment Key Dates

6/4/2018

Monitoring Start

9/18/2022

Monitoring End

5/19/2017

Fish Tissue Monitoring

7/1/2019

Fish Tissue Monitoring

1/30/2003

TMDL Completed

4/1/2011

TMDL Completed

Methods

200

Physical/Chemical Monitoring

260

Fish tissue analysis

340

Primary producer surveys (phytoplankton/periphyton/macrophyton)

420

Indicator bacteria monitoring