Three Mile Lake IA 05-GRA-1371

Union County S32 T73N R29W approximately 3 miles N or Afton.

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.

Open Segment Map
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Cycle: 2022
Release Status: Final
Overall IR: 1 - All designated uses are met.
Trophic: Eutrophic
Trend: Stable
Created: 12/30/2021 1:58:52 PM
Updated: 1/6/2022 7:26:05 AM

Use Support

Class BLW

Aquatic Life - Lakes and wetlands

Fully Supported

Class C

Drinking Water -

Fully Supported

Class HH

Human Health -

Fully Supported

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The Class BLW use was assessed (monitored) as “fully supported.” The Class C (drinking water) use was assessed (monitored) as "fully supported." The Class HH (fish consumption) use remains assessed (evaluated) as “fully supported” based on fish tissue sampling data. Note: This lake is not designated for Class A1 (primary contact recreation) uses in the Iowa Water Quality Standards.

Assessment Explanation

Data Sources:

Data Source	Data Source ID	Data Type	Data Age	Site ID	Site Name	Site Description
Iowa DNR	6	WQ	CY 2016-2020	22880003	Three Mile Lake
Iowa DNR	6	FT	See Below	166	Three Mile Lake	Near Afton

Class A1 - Indicator Bacteria: No Data

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
22880003	6	14 / 5	7.7	8.6	8.3	0	4	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
22880003	6	Chlorophyll a TSI	14 / 5	15	70	51	NO	Monitored	Full
22880003	6	Secchi TSI	14 / 5	40	70	62	NO	Monitored	Full
22880003	6	Total Phosphorus TSI	14 / 5	45	75	62	NA	NA	NA
22880003	6	Inorganic suspended solids	14 / 5	0.6	11	3.5	NA	NA	NA

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
22880003	6	Ammonia	14 / 5	0.0003	0.1964	0.04	NA	0 / 0	4	NO	Monitored	Full
22880003	6	Dissolved Oxygen	14 / 5	3	10.1	7.4	1	NA / NA	4	NO	Monitored	Full
22880003	6	pH	14 / 5	7.7	8.6	8.3	0	NA / NA	4	NO	Monitored	Full
22880003	6	Temperature	14 / 5	18.3	27.2	23.7	0	NA / NA	4	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
22880003	6	5	15.21	94.8%	7.08	63.6%	NO	Evaluated	NA

Class C - Conventional 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
22880003	6	Inorganic nitrogen (nitrate and nitrite)	14 / 5	0.02	1.9	0.5	0.0325	0	NO	Monitored	Full
22880003	6	pH	14 / 5	7.7	8.6	8.3	8.3	0	NO	Monitored	Full

Class C - Toxic Parameters: Syngenta “Iowa Voluntary Atrazine Monitoring Program” from 2010 through 2012

Parameter Name	# Samples / # Years	Maximum Value	Mean Value	% Violations	Number of Non - Detects	Mean Value > Criterion or MCL	Assessment Type	Support Level
Atrazine	102 / 3	1.8	5.2	2%	NA	No	Monitored	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)
166	tissue plug	2011	walleye	5	39.8	0.12
Support Level	Full

Monitoring and Methods

Assessment Key Dates

6/13/2016

Fixed Monitoring Start Date

9/22/2020

Fixed Monitoring End Date

9/27/2011

Fish Tissue Monitoring

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

270

PWS chemical monitoring (ambient water)

340

Primary producer surveys (phytoplankton/periphyton/macrophyton)