Kent Park Lake IA 02-IOW-694

Johnson County S24T80NR8W 2.5 mi. W of Tiffin.

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: 4 - Water is impaired or threatened and a TMDL has been completed or is not needed.
Trophic: Eutrophic
Trend: Stable
Created: 12/21/2021 3:10:56 PM
Updated: 2/17/2022 9:53:56 AM

Use Support

Class A1

Recreation - Primary contact

Not Supported

Algal Growth: Chlorophyll a

Support Level

Not Supported

Impairment Code

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

Cause Magnitude

Moderate

Status

Continuing

Source

Agriculture

Source Confidence

Low

Cycle Added

2010

Impairment Rationale

Narrative criteria violation: aesthetically objectionable conditions

Data Source

Ambient monitoring: Iowa DNR-lakes

Class BLW

Aquatic Life - Lakes and wetlands

WINOFI

Algal Growth: Cyanobacteria

Support Level

Further Investigation Needed

Impairment Code

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

Cause Magnitude

Slight

Status

New

Source

Unknown: Source Unknown

Source Confidence

N/A

Cycle Added

2022

Impairment Rationale

Adverse impacts on plant/animal communities

Data Source

Ambient monitoring: Iowa DNR-lakes

Class HH

Human Health -

Fully Supported

Impairment Delistings

Cycle Added	Class	Cause	Data Source	Rationale
2022	Class A1	Bacteria: Indicator Bacteria- E. coli	Ambient monitoring: Iowa DNR-lakes	New data: WQ improvement (chemical / physical / bacterial)

Documentation

Assessment Summary

The Class A1 use was assessed as “not supported” due to high levels of algae that violated Iowa's narrative criteria protecting against aesthetically objectionable conditions. The level of inorganic suspended solids was low at Kent Park Lake and does not suggest water quality problems due to non-algal turbidity. The Class BLW use was assessed (evaluated) as “WINOFI” due to cyanobacteria blooms. The Class HH (fish consumption) use was assessed as "fully supported" based on fish tissue sampling data. Note: A TMDL for the algae and pH impairments at Kent Park Lake was prepared by Iowa DNR and was approved by U.S.EPA in June 2015.

Assessment Explanation

Data Sources:

Data Source	Data Source ID	Data Type	Data Age	Site ID	Site Name	Site Description
Iowa DNR	6	WQ	CY 2019-2020	21520002	F. W. Kent Park Beach
Iowa DNR	6	WQ	CY 2016-2020	22520005	Kent Park Lake
Iowa DNR	6	FT	See Below	306	Kent Park Lake	Kent Park NW of Tiffin

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

21520002

0/5/12

0 / NA

1 / 4

Monitored

Full

Kent Park Lake was assessed as "not supported" for the 2014 assessment/listing cycle. Based on DNR’s assessment methodology 2 consecutive assessment/listing cycles without violations of the geometric mean criterion and without significantly greater than 10% of the samples violating the single-sample maximum criterion are necessary 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 2020 or current 2022 assessment listing cycle. Therefore, the impairment for indicator bacteria is suggested for delisting for the 2022 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
22520005	6	9 / 3	7.9	8.7	8.3	0	3	NO	Evaluated	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
22520005	6	Chlorophyll a TSI	9 / 3	26	75	57	NO	Monitored	Full
22520005	6	Secchi TSI	9 / 3	46	77	59	NO	Monitored	Full
22520005	6	Total Phosphorus TSI	9 / 3	35	79	56	NA	NA	NA
22520005	6	Inorganic suspended solids	9 / 3	0.6	7	1.6	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 Kent Park Lake remains 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, Kent Park Lake will remain listed as "not supported" (4a) 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
22520005	6	Ammonia	9 / 3	0.0003	0.283	0.04	NA	0 / 0	3	NO	Evaluated	Full
22520005	6	Dissolved Oxygen	9 / 3	4.5	15.1	9.5	1	NA / NA	3	NO	Evaluated	Full
22520005	6	pH	9 / 3	7.9	8.7	8.3	0	NA / NA	3	NO	Evaluated	Full
22520005	6	Temperature	9 / 3	19.1	28.3	24.7	0	NA / NA	3	NO	Evaluated	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
22520005	6	4	25.45	95.7%	17.37	86.1%	YES	Evaluated	3b

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)
306	fillet	2013	channel catfish	3	47.8	0.05	<0.2	<0.6
306	tissue plug	2013	largemouth bass	5	31.7	0.107
Support Level	Full

Monitoring and Methods

Assessment Key Dates

6/21/2016

Fixed Monitoring Start Date

9/14/2020

Fixed Monitoring End Date

8/9/2013

Fish Tissue Monitoring

6/26/2015

TMDL Completed

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