Storm Lake IA 04-RAC-1143

Buena Vista County S14T90NR37W at Storm Lake.

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.

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Cycle: 2024
Release Status: Final
Overall IR: 5 - Water is impaired or threatened and a TMDL is needed.
Trophic: Eutrophic
Trend: Stable
Created: 11/1/2023 8:13:07 AM
Updated: 2/5/2024 9:03:00 AM

Use Support

Class A1

Recreation - Primary contact

Not Supported

Bacteria: Indicator Bacteria- E. coli

Support Level

Not Supported

Impairment Code

5a - Pollutant-caused impairment. TMDL needed.

Cause Magnitude

Moderate

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

Moderate

Cycle Added

2010

Impairment Rationale

Geometric mean criterion exceeded

Data Source

Beach monitoring: Iowa DNR city/county

TMDL Priority

Tier II

Turbidity

Support Level

Not Supported

Impairment Code

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

Cause Magnitude

High

Status

Continuing

Source

Other: Sediment Resuspension

Source Confidence

High

Cycle Added

2002

Impairment Rationale

Narrative criteria violation: aesthetically objectionable conditions

Data Source

Ambient monitoring: Iowa DNR-lakes

Class BLW

Aquatic Life - Lakes and wetlands

WINOFI

Turbidity

Support Level

Further Investigation Needed

Impairment Code

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

Cause Magnitude

High

Status

Continuing

Source

Other: Sediment Resuspension

Source Confidence

High

Cycle Added

2002

Impairment Rationale

Adverse impacts on plant/animal communities

Data Source

Biological monitoring: Iowa DNR Fisheries

Class HH

Human Health -

Fully Supported

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The Class A1 use was assessed (monitored) as “not supported” due to poor water transparency caused by inorganic suspended solids that violates Iowa’s narrative water quality standard protecting against aesthetically objectionable conditions and levels of indicator bacteria at a swimming beach that exceeded the state water quality criteria. The Class BLW use was assessed (evaluated) as “WINOFI” (IR 3b) due to excessive nutrient loading to the water column and re-suspension of sediment. The Class HH (fish consumption) use was assessed as "fully supported" based on fish tissue sampling data. Note: A TMDL for turbidity at Storm Lake was prepared by DNR and approved by EPA in 2005; thus, this impairment is placed in IR Category 4a (impaired; TMDL approved) for the current assessment/ listing cycle. Because however, the bacteria impairment is not addressed by the TMDL, this impairment will be placed in Category 5a of the this Integrated Report (i.e., Section 303(d) list).

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	14000121	Frank Starr Beach
Iowa DNR	6	WQ	CY 2020-2020	21110004	Awaysis Beach
Iowa DNR	6	WQ	CY 2020-2020	21110005	Bel Air Beach
Iowa DNR	6	WQ	CY 2020-2020	21110006	Casino Beach
Iowa DNR	6	WQ	CY 2020-2020	21110008	Edson Park Beach
Iowa DNR	6	WQ	CY 2020-2020	21110009	Old Water Plant Beach
Iowa DNR	6	WQ	CY 2018-2022	22110001	Storm Lake Max Depth
Iowa DNR	6	FT	See Below	1129	Storm Lake	At Storm Lake

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

14000121

5/3/8

148

136

YES

2 / NA

0 / NA

3 / 3

YES

Mon

Not

21110004

10/6/4

365

122

YES

5 / 3

2 / NA

YES

Mon

Not

21110005

6/6/9

1 / NA

0 / NA

1 / 3

Mon

Full

21110006

5/4/8

0 / NA

0 / 3

Mon

Full

21110008

7/6/9

228

110

259

YES

5 / 3

1 / NA

6 / 3

YES

Mon

Not

21110009

3/3/7

0 / NA

1 / 3

Mon

Full

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
22110001	6	15 / 5	7.9	9.2	8.3	1	4	NO	Mon	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
22110001	6	Chlorophyll a TSI	33 / 5	22	75	48	NO	Mon	Full
22110001	6	Secchi TSI	32 / 5	53	77	68	YES	Mon	Not
22110001	6	Total Phosphorus TSI	33 / 5	46	92	68	NA	NA	NA
22110001	6	Inorganic suspended solids	33 / 5	0.7	19	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
22110001	6	Dissolved Oxygen	14 / 5	6.9	13.2	8.6	0	NA / NA	4	NO	Mon	Full
22110001	6	pH	15 / 5	7.9	9.2	8.3	1	NA / NA	4	NO	Mon	Full
22110001	6	Temperature	15 / 5	13.6	27.7	22.1	0	NA / NA	4	NO	Mon	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
22110001	6	6	5.512826999	21%	0.062131049	2%	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
22110001	6	Ammonia	15 / 5	0.2148	0.05	0.03	0 / 0	NO	Mon	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)
1129	tissue plug	2021	northern pike	2		0.126
1129	tissue plug	2019	walleye	20	49.5	0.082
Support Level	Full

Monitoring and Methods

Assessment Key Dates

5/14/2018

Monitoring Start

9/11/2022

Monitoring End

4/10/2021

Fish Tissue Monitoring

5/3/2005

TMDL Completed

7/1/2019

Fish Tissue Monitoring

Methods

200

Physical/Chemical Monitoring

260

Fish tissue analysis

340

Primary producer surveys (phytoplankton/periphyton/macrophyton)

420

Indicator bacteria monitoring