Big Spirit Lake IA 06-LSR-1655

Dickinson County S33T100NR36W at Spirit 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.

Open Segment Map
View assessment methodology in new window

Cycle: 2024
Release Status: Final
Overall IR: 2 - Some of the designated uses are met but there is insufficient data to determine if remaining designated uses are met.
Trophic: Eutrophic
Trend: Stable
Created: 11/1/2023 8:13:34 AM
Updated: 2/5/2024 11:48:30 AM

Use Support

Class A1

Recreation - Primary contact

Fully Supported

Class BLW

Aquatic Life - Lakes and wetlands

WINOFI

Fish Kill: Due To Natural Causes

Support Level

Further Investigation Needed

Impairment Code

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

Cause Magnitude

High

Status

Continuing

Source

Natural: Ordinary Stratification and Bottom-Water Hypoxia/Anoxia

Source Confidence

Low

Cycle Added

2010

Impairment Rationale

Non Pollutant-caused fish kill

Data Source

Fish kill investigation: Iowa DNR

Algal Growth: Cyanobacteria

Support Level

Further Investigation Needed

Impairment Code

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

Cause Magnitude

Slight

Status

Continuing

Source

Agriculture

Source Confidence

Low

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 -

WINOFI

Metals: Mercury

Support Level

Further Investigation Needed

Impairment Code

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

Cause Magnitude

Slight

Status

New

Source

Atmospheric Deposition

Source Confidence

Low

Cycle Added

2024

Impairment Rationale

Potential Impairment

Data Source

Fish contaminant monitoring: Iowa DNR

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The Class A1 use was assessed (monitored) as “fully supported.” The Class BLW use was assessed (evaluated) as “WINOFI” based on the results of fish kill investigations. In addition, the Class BLW use was assessed (evaluated) as “WINOFI” due to cyanobacteria blooms. The Class C use was assessed (monitored) as “fully supported” based on water quality monitoring data and drinking water compliance monitoring required by the DNR. The Class HH (fish consumption) use was assessed (evaluated) as “WINOFI” based on fish tissue sampling data.

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	14000380	Marble Beach (Marble Beach State Park)
Iowa DNR	6	WQ	CY 2020-2022	21300005	Crandalls Beach
Iowa DNR	6	WQ	CY 2021-2022	21300007	Orleans City Beach
Iowa DNR	6	WQ	CY 2018-2022	22300014	Big Spirit Lake
Iowa DNR	6	FT	See Below	1153	Big Spirit Lake	N of Spirit 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

14000380

6/15/15

0 / NA

1 / 4

2 / 4

Mon

Full

21300005

15/15/15

0 / 4

2 / 4

1 / 4

Mon

Full

21300007

0/15/15

2 / 4

1 / 4

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
22300014	6	12 / 4	7.986	8.889	8.46	0	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
22300014	6	Chlorophyll a TSI	15 / 5	28	75	54	NO	Mon	Full
22300014	6	Secchi TSI	15 / 5	34	73	55	NO	Mon	Full
22300014	6	Total Phosphorus TSI	15 / 5	34	82	58	NA	NA	NA
22300014	6	Inorganic suspended solids	15 / 5	0.6	4	1.7	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
22300014	6	Dissolved Oxygen	12 / 5	6.1	10.9	9	0	NA / NA	4	NO	Mon	Full
22300014	6	pH	12 / 4	7.986	8.889	8.46	0	NA / NA	4	NO	Mon	Full
22300014	6	Temperature	13 / 5	15.3	26.9	22.5	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
22300014	6	2	27.95012214	95%	13.98810049	56%	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
22300014	6	Ammonia	12 / 4	0.053	0.01	0.01	0 / 0	NO	Mon	Full

Class BLW - Fish Kill Assessment:

The Class BLW aquatic life use assessment based on the July 2018, August 2018, and 2020 fish kills placed this segment in Category 3b. This assessment was “evaluated” because: (1) the cause of the fish kill was not identified or (2) the fish kill was attributed to a non-pollutant cause (e.g., winterkill). Segments assessed using “evaluated” assessments are placed in Category 3b and are added to the state list of Waters In Need Of Further Investigation (WINOFI). If no additional fish kills are reported in this segment for a 5-year period (2023), the Category will be changed from 3b to 3a (not assessed).

Details about the July 2018 fish kill can be found here:https://programs.iowadnr.gov/fishkill/Events/931

Details about the August 2018 fish kill can be found here:https://programs.iowadnr.gov/fishkill/Events/989

Details about the 2020 fish kill can be found here:https://programs.iowadnr.gov/fishkill/Events/996

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
22300014	6	Inorganic nitrogen (nitrate and nitrite)	14 / 5	0.02	0.32	0.1	0.06	0	NO	Mon	Full
22300014	6	pH	12 / 4	7.986	8.889	8.46	8.41	0	NO	Mon	Full

Class C - Iowa Drinking Water Compliance Report:

Compliance monitoring required by the Iowa DNR Water Supply Operations and Engineering Sections did not show violations of finished water that were caused by source water at the Spirit Lake Waterworks facility during the 2020-22 monitoring period. The violations reported were related to plant operations (Failure to maintain Res Disinfect Concentration).The results of compliance monitoring as reported in annual compliance reports are available at the following location at the Iowa DNR’s home page: https://www.iowadnr.gov/Environmental-Protection/Water-Quality/Water-Supply-Engineering/Annual-Compliance-Report.

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)
1153	tissue plug	2021	muskie	1		0.370
1153	tissue plug	2020	muskie	3	95.1	0.192
1153	tissue plug	2019	northern pike	20	65.6	0.113
1153	tissue plug	2020	walleye	13	49.1	0.25
1153	tissue plug	2019	walleye	7	48.9	0.171
1153	tissue plug	2020	yellow perch	10	23.6	0.041
Support Level	WINOFI

Monitoring and Methods

Assessment Key Dates

5/30/2018

Monitoring Start

9/11/2022

Monitoring End

7/20/2018

Fish Kill

8/13/2018

Fish Kill

7/1/2019

Fish Tissue Monitoring

6/16/2020

Fish Kill

7/1/2020

Fish Tissue Monitoring

4/6/2021

Fish Tissue Monitoring

Methods

200

Physical/Chemical Monitoring

260

Fish tissue analysis

275

Drinking water compliance reports

340

Primary producer surveys (phytoplankton/periphyton/macrophyton)

420

Indicator bacteria monitoring