DRAFT 2026 assessment for Lake Of Three Fires

Lake Of Three Fires IA 05-PLA-1476

Taylor County S12T68NR34W 2 mi NNE of Bedford.

This is a DRAFT assessment

Draft assessments may change without notice

2026
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 2022 - 2024
Stream/River Water Quality Data	CY 2022 - 2024
Lake Water Quality Data	CY 2020 - 2024
Biological Sampling Data	CY 2020 - 2024*
Fish Kill Data	CY 2020 - 2024
Fish Tissue Sampling Data	CY 2020 - 2024
Continuous Dissolved Oxygen Sampling Data	CY 2020 - 2024
*Biological sites sampled in both 2019 and 2023 were also assessed.

Open Segment Map
View 2026 assessment summary page

Overall IR

5 - Water is impaired or threatened and a TMDL is needed.

Trophic

Eutrophic

Trend

Stable

Current Phase

Public Comment

Created

10/27/2025 3:10:16 PM by

Updated

11/24/2025 2:32:23 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

Continuing

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

Not Supported

Organic Enrichment: Low Dissolved Oxygen

Support Level

Not Supported

Impairment Code

5a - Pollutant-caused impairment. TMDL needed.

Cause Magnitude

High

303(d) Listing Status

New

Source

Agriculture

Source Confidence

Low

Cycle Added

2026

Impairment Rationale

Significantly > 10% of samples fail to meet criterion

Data Source

Ambient monitoring: Iowa DNR-lakes

TMDL Priority

Tier III

Class C

Drinking Water -

Fully Supported

Class HH

Human Health -

Fully Supported

303(d) Delistings for this Cycle

No delistings for this assessment cycle.

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 (monitored) as “not supported" due to violations of the state's criterion for dissolved oxygen. 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) 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 2022-2024	21870001	Lake of Three Fires Beach
Iowa DNR	6	WQ	CY 2021-2024	22870001	Lake of Three Fires Max Depth
Iowa DNR	6	TF	See Below	1156	Lake of Three Fires

Class A1 - Indicator Bacteria:

Site ID

Data Source ID

# Samples per Year (2022/ 2023/2024)

2022 Geometric Mean

2023 Geometric Mean

2024 Geometric Mean

Violates Annual Geometric Mean?

# 2022 SSM violations / SSM Violations needed for impairment

# 2023 SSM violations / SSM Violations needed for impairment

# 2024 SSM violations / SSM Violations needed for impairment

Violates Annual SSM Significantly >10% Rule?

Assessment Type

Support Level

21870001

15/14/15

208

YES

4 / 4

0 / 4

7 / 4

YES

MONITORED

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	8.9	8	0	4	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
22870001	6	Chlorophyll a TSI	12 / 4	67	80	72	YES	MONITORED	NOT
22870001	6	Secchi TSI	12 / 4	61	74	68	YES	MONITORED	NOT
22870001	6	Total Phosphorus TSI	12 / 4	65	73	68	NA	NA	NA
22870001	6	Fixed suspended solids	12 / 4	1.9	9	3.5	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	3.33	9.33	5.88	4	NA / NA	4	YES	MONITORED	NOT
22870001	6	pH	12 / 4	7.3	8.9	8	0	NA / NA	4	NO	MONITORED	FULL
22870001	6	Temperature	12 / 4	16.2	28.4	23.4	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
22870001	6	4	269.644076	99.90%	11.29173321	73.56%	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
22870001	6	Ammonia	12 / 4	0.381	0.11	0.06	0 / 0	NO	MONITORED	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	0.05	0.64	0.2	0.15	0	NO	MONITORED	FULL
22870001	6	pH	12 / 4	7.3	8.9	8	7.7	0	NO	MONITORED	FULL

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

5/26/2021

Monitoring Start

10/1/2024

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