Lake Macbride IA 02-IOW-629

Johnson County S29T81NR6W 4 mi. W of Solon.

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
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Cycle: 2024
Release Status: Final
Overall IR: 1 - All designated uses are met.
Trophic: Eutrophic
Trend: Stable
Created: 11/1/2023 8:12:43 AM
Updated: 2/2/2024 2:44:21 PM

Use Support

Class A1

Recreation - Primary contact

Fully Supported

Class BLW

Aquatic Life - Lakes and wetlands

Fully Supported

Class HH

Human Health -

Fully Supported

Impairment Delistings

Cycle Added	Class	Cause	Data Source	Rationale
2006	Class A1	Bacteria: Indicator Bacteria- E. coli	Beach monitoring: Iowa DNR WQMA	New data: WQ improvement (chemical / physical / bacterial)
2010	Class A1	Algal Growth: Chlorophyll a	Ambient monitoring: Iowa DNR-lakes	New data: WQ improvement (chemical / physical / bacterial)

Documentation

Assessment Summary

The Class A1 use was assessed as “fully supported.” The Class BLW use was assessed as “fully supported.”. The Class HH (fish consumption) use was assessed as "fully supported" based on fish tissue sampling data. Note: A TMDL for nutrients and siltation at Lake MacBride was prepared by DNR and approved by EPA in 2005. Additionally, a TMDL for Escherichia coli at Lake MacBride was prepared by DNR and approved by EPA in 2022

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	21520001	Lake Macbride Beach
Iowa DNR	6	WQ	CY 2018-2019	14000237	McBride N Arm
Iowa DNR	6	WQ	CY 2018-2019	14000238	McBride S Arm
Iowa DNR	6	WQ	CY 2018-2022	22520001	Lake Macbride (maximum water depth)
Iowa DNR	6	FT	See Below	1081	Lake Macbride	WSW of Solon

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

21520001

13/15/15

3 / 4

2 / 4

1 / 4

Mon

Full

Lake Macbride was assessed as "not supported" for the 2006 assessment/listing cycle. Based on DNR’s assessment methodology the current assessment/listing cycle must be without violations of the geometric mean criterion and without significantly greater than 10% of the samples violating the single-sample maximum criterion to propose delisting based on bacteria violations. There were no violations of the geometric mean criterion and there were less than 10% of the samples exceeding the single-sample maximum criterion for the current 2024 assessment listing cycle. Therefore, the impairment for indicator bacteria is suggested for delisting for the 2024 assessment/listing cycle.

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
14000237	6	26 / 2	7.7	9.2	8.7	4	6	NO	Mon	Full
14000238	6	27 / 2	7.5	9.3	8.7	2	6	NO	Mon	Full
22520001	6	46 / 5	7.3	9.2	8.5	2	8	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
22520001	6	Chlorophyll a TSI	44 / 5	24	72	62	NO	Mon	Full
22520001	6	Secchi TSI	15 / 5	39	70	63	NO	Mon	Full
22520001	6	Total Phosphorus TSI	44 / 5	37	83	62	NA	NA	NA
22520001	6	Fixed suspended solids	15 / 5	0.6	5.5	1.7	NA	NA	NA

DNR's assessment methodology indicates that a TSI value less than or equal to 63 is necessary to suggest de-listing of an impairment. The chlorophyll a TSI value for the 2010 assessment listing cycle was 64, which indicated a threat of impairment. For the 2016 assessment listing cycle was 65, which based on DNR's assessment/listing methodology indicated impairment based on the narrative criteria protecting against aesthetically objectionable conditions. Because the TSI value for the 2024 assessment/listing cycle is less than or equal to the delisting threshold of 63 (median TSI value for chlorophyll a was 62), based on DNR's methodology, these values suggest "full support" of the Class A1 uses protecting against aesthetically objectionable conditions and the impairment (5a) for chlorophyll a is suggested for delisting for the 2024 assessment/listing cycle.

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
14000237	6	Dissolved Oxygen	26 / 2	4.1	15.9	9.9	1	NA / NA	6	NO	Mon	Full
14000238	6	Dissolved Oxygen	27 / 2	5.6	16.2	10.3	0	NA / NA	6	NO	Mon	Full
21520001	6	Dissolved Oxygen	28 / 2	7.3	15.3	10.3	0	NA / NA	6	NO	Mon	Full
22520001	6	Dissolved Oxygen	46 / 5	1.3	17.3	9.2	2	NA / NA	8	NO	Mon	Full
14000237	6	pH	26 / 2	7.7	9.2	8.7	4	NA / NA	6	NO	Mon	Full
14000238	6	pH	27 / 2	7.5	9.3	8.7	2	NA / NA	6	NO	Mon	Full
21520001	6	pH	28 / 2	8.2	9.1	8.7	4	NA / NA	6	NO	Mon	Full
22520001	6	pH	46 / 5	7.3	9.2	8.5	2	NA / NA	8	NO	Mon	Full
14000237	6	Temperature	26 / 2	9.3	29.1	21.6	0	NA / NA	6	NO	Mon	Full
14000238	6	Temperature	27 / 2	9.9	28.9	21.5	0	NA / NA	6	NO	Mon	Full
21520001	6	Temperature	28 / 2	18.8	29.3	26	0	NA / NA	6	NO	Mon	Full
22520001	6	Temperature	46 / 5	9.7	28.7	22.6	0	NA / NA	8	NO	Mon	Full

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
14000237	6	Ammonia	25 / 2	0.3	0.1	0.02	0 / 0	NO	Mon	Full
14000238	6	Ammonia	26 / 2	0.44	0.08	0.02	0 / 0	NO	Mon	Full
22520001	6	Ammonia	43 / 5	0.85	0.08	0.02	0 / 0	NO	Mon	Full

Class BLW - Fish Kill:

The Class BLW uses are assessed (evaluated) as “WINOFI” due to a fish kill that on June 7, 2011. According to DNR's assessment methodology, the 3b will be removed if no additional kills happen within 5 years.

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)
1081	tissue plug	2021	hybrid striped bass	10		0.09
1081	tissue plug	2021	white bass	10		0.103
1081	tissue plug	2020	channel catfish	4	55.7	0.084
Support Level	Full

Monitoring and Methods

Assessment Key Dates

4/24/2018

Monitoring Start

9/27/2022

Monitoring End

7/1/2020

Fish Tissue Monitoring

5/3/2005

TMDL Completed

4/20/2021

Fish Kill

6/29/2021

Fish Tissue Monitoring

4/19/2021

Fish Tissue Monitoring

Methods

200

Physical/Chemical Monitoring

260

Fish tissue analysis

340

Primary producer surveys (phytoplankton/periphyton/macrophyton)

420

Indicator bacteria monitoring