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 2018 - 2020
Stream/River Water Quality Data	CY 2018 - 2020
Lake Water Quality Data	CY 2016 - 2020
Biological Sampling Data	CY 2016 - 2020*
Fish Kill Data	CY 2016 - 2020
Fish Tissue Sampling Data	CY 2016 - 2020
Continuous Dissolved Oxygen Sampling Data	CY 2016 - 2020
*Biological sites sampled in both 2015 and 2019 were also assessed.

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Cycle: 2022
Release Status: Final
Overall IR: 5 - Water is impaired or threatened and a TMDL is needed.
Trophic: Eutrophic
Trend: Stable
Created: 12/20/2021 8:57:28 AM
Updated: 2/10/2022 8:46:12 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

Slight

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

Low

Cycle Added

2006

Impairment Rationale

Geometric mean criterion exceeded

Data Source

Beach monitoring: Iowa DNR WQMA

TMDL Priority

Tier II

Algal Growth: Chlorophyll a

Support Level

Not Supported

Impairment Code

5* - 303(d)-impaired last cycle; fully supporting this cycle; potential de-listing.

Cause Magnitude

Moderate

Status

Continuing

Source

Agriculture

Source Confidence

Moderate

Cycle Added

2010

Impairment Rationale

Narrative criteria violation: aesthetically objectionable conditions

Data Source

Ambient monitoring: Iowa DNR-lakes

TMDL Priority

Tier II

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

Slight

Status

Continuing

Source

Natural

Source Confidence

Low

Cycle Added

2016

Impairment Rationale

Non Pollutant-caused fish kill

Data Source

Fish kill investigation: Iowa DNR

Class HH

Human Health -

Fully Supported

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The Class A1 use was assessed as “not supported” due to levels of indicator bacteria that exceeded Iowa’s water quality standard and due to poor water transparency caused by algae blooms. The Class BLW use was assessed (evaluated) as “WINOFI” due to a fish kill. 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. Because however, the Section 303(d) impairment due to indicator bacteria and DO violations at this lake were not addressed in the TMDL, this lake was placed in IR Category 5a (impaired; TMDL required).

Assessment Explanation

Data Sources:

Data Source	Data Source ID	Data Type	Data Age	Site ID	Site Name	Site Description
Iowa DNR	6	WQ	CY 2018-2018	14000212	McBride bac 1
Iowa DNR	6	WQ	CY 2018-2018	21520001	Lake Macbride Beach (Lake Macbride State Park)
Iowa DNR	6	WQ	CY 2016-2020	22520001	Lake Macbride (maximum water depth)
Iowa DNR	6	WQ	CY 2018-2018	22520006	Lake Macbride near Cottage Grove
Iowa DNR	6	WQ	CY 2018-2018	22520007	Lake Macbride near campground
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	FT	See Below	81	Lake Macbride	WSW of Solon

Class A1 - Indicator Bacteria:

Site ID

Data Source ID

# Samples per Year (2018/ 2019/2020)

2018 Geometric Mean

2019 Geometric Mean

2020 Geometric Mean

Violates Annual Geometric Mean?

# 2018 SSM violations / SSM Violations needed for impairment

# 2019 SSM violations / SSM Violations needed for impairment

# 2020 SSM violations / SSM Violations needed for impairment

Violates Annual SSM Significantly >10% Rule?

Assessment Type

Support Level

14000212

6/0/0

0 / NA

Evaluated

Full

21520001

15/15/13

263

YES

9 / 4

2 / 4

3 / 4

YES

Monitored

Not

22520001

9/3/3

0 / 3

0 / NA

Monitored

Full

22520006

6/0/0

0 / NA

Evaluated

Full

22520007

5/0/0

0 / NA

Evaluated

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
14000237	6	26 / 2	7.7	9.2	8.7	4	6	NO	Monitored	Full
14000238	6	27 / 2	7.5	9.3	8.7	2	6	NO	Monitored	Full
22520001	6	47 / 5	7.3	9.2	8.5	3	8	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
22520001	6	Chlorophyll a TSI	45 / 5	24	80	62	NO	Monitored	Full
22520001	6	Secchi TSI	16 / 5	47	70	63	NO	Monitored	Full
22520001	6	Total Phosphorus TSI	45 / 5	49	88	63	NA	NA	NA
22520001	6	Fixed suspended solids	16 / 5	0.4	5	1	NA	NA	NA

Although the index value for Chlorophyll a is below the impairment trigger of 65 for this assessment cycle, the Class A1 use of Lake Macbride was listed as "not supported"due to aesthetically objectionable conditions. Based on DNR's methodology, the median TSI value for Chlorophyll a must be 63 or less for two consecutive assessment/listing cycles before a lake can be removed from the state's Section 303(d) list (IR Category 5). Therefore, Lake Macbride will remain listed as "not supported" for the 2022 assessment/listing cycle.

Class BLW - Conventional 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	Ammonia	25 / 2	0.025	0.3	0.1	NA	0 / 0	5	NO	Monitored	Full
14000238	6	Ammonia	26 / 2	0.02	0.44	0.08	NA	0 / 0	6	NO	Monitored	Full
22520001	6	Ammonia	44 / 5	0.0003	0.85	0.08	NA	0 / 0	8	NO	Monitored	Full
14000237	6	Dissolved Oxygen	26 / 2	4.1	15.9	9.9	1	NA / NA	6	NO	Monitored	Full
14000238	6	Dissolved Oxygen	27 / 2	5.6	16.2	10.3	0	NA / NA	6	NO	Monitored	Full
22520001	6	Dissolved Oxygen	47 / 5	1.3	17.9	9.3	1	NA / NA	8	NO	Monitored	Full
14000237	6	pH	26 / 2	7.7	9.2	8.7	4	NA / NA	6	NO	Monitored	Full
14000238	6	pH	27 / 2	7.5	9.3	8.7	2	NA / NA	6	NO	Monitored	Full
22520001	6	pH	47 / 5	7.3	9.2	8.5	3	NA / NA	8	NO	Monitored	Full
14000237	6	Temperature	26 / 2	9.3	29.1	21.6	0	NA / NA	6	NO	Monitored	Full
14000238	6	Temperature	27 / 2	9.9	28.9	21.5	0	NA / NA	6	NO	Monitored	Full
22520001	6	Temperature	47 / 5	9.7	28.7	22.5	0	NA / NA	8	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
22520001	6	6	707.76	93.1%	8.53	78.3%	NO	Evaluated	NA

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 occurrence of a single pollutant-caused fish kill, or a fish kill of unknown origin, on a waterbody or waterbody reach during the most recent assessment period indicates a severe stress to the aquatic community and suggests that the aquatic life uses should be assessed as “impaired.” If a cause of the kill was not identified during the DNR investigation, or if the kill was attributed to non-pollutant causes (e.g., winterkill), the assessment type will be considered “evaluated” and will be placed in IR subcategory 3b and will be added to the state list of waters in need of further investigation

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)
81	tissue plug	2020	channel catfish	4	55.7	0.084
Support Level	Full

Monitoring and Methods

Assessment Key Dates

6/21/2016

Non-fixed Monitoring Start Date

9/14/2020

Non-fixed Monitoring End Date

7/1/2020

Fish Tissue Monitoring

5/3/2005

TMDL Completed

6/7/2011

Fish Kill

Methods

120

Surveys of fish and game biologists/other professionals

222

Non-fixed-station monitoring (conventional during key seasons and flows)

260

Fish tissue analysis

340

Primary producer surveys (phytoplankton/periphyton/macrophyton)

420

Indicator bacteria monitoring