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 2016 - 2018
Stream/River Water Quality Data	CY 2016 - 2018
Lake Water Quality Data	CY 2014 - 2018
Biological Sampling Data	CY 2014 - 2018*
Fish Kill Data	CY 2014 - 2018
Fish Tissue Sampling Data	CY 2014 - 2018
Continuous Dissolved Oxygen Sampling Data	CY 2014 - 2018
*Biological sites sampled in both 2013 and 2017 were also assessed.

Open Segment Map
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Cycle: 2020
Release Status: Final
Overall IR: 1 - All designated uses are met.
Trophic: Eutrophic
Trend: Stable
Created: 8/21/2020 2:54:39 PM
Updated: 10/14/2020 2:53:02 PM

Use Support

Class BLW

Aquatic Life - Lakes and wetlands

Fully Supported

Class C

Drinking Water -

Fully Supported

Class HH

Human Health -

Fully Supported

General Use

General Use water -

Not Assessed

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The Class BLW uses are assessed (monitored) as “fully supported.” The Class C (drinking water) uses are assessed (monitored) as "fully supported" based on atrazine and Inorganic nitrogen monitoring. Class HH uses remain assessed (monitored) as “fully supported” based on results of fish contaminant monitoring in 2011. Note: This lake is not designated for Class A1 (primary contact recreation) uses in the Iowa Water Quality Standards.

Assessment Explanation

Sources of Data:

Data Source	Data Source ID	Data Type	Data Age	Site ID	Site Name	Site Description
Iowa DNR	6	WQ	CY 2014-2018	22880003	Three Mile Lake	Lake Deep Point
Iowa DNR		FT	See Below	166	Three Mile Lake

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	67	58	NO	Monitored	Full
22880003	6	Secchi TSI	14 / 5	40	70	60	NO	Monitored	Full
22880003	6	Total Phosphorus TSI	14 / 5	45	72	56	NA	NA	NA
22880003	6	Inorganic suspended solids	14 / 5	1.05	11	4.4	NA	NA	NA

Class BLW - Conventional Parameters:

Site ID	Data Source ID	Parameter Name	# Samples / # Years	Maximum Value	Mean Value	Median Value	# Acute / Chronic Violations	% Acute/ Chronic Violations	Significantly >10% Violations	Assessment Type	Support Level
22880003	6	Ammonia	14 / 5	0.3404	0.06	0.04	0 / 0	0% / 0%	NO	Monitored	Full
22880003	6	Dissolved oxygen	14 / 5	9.1	6.8	6.8	NA / 2	NA / 14%	NO	Monitored	Full
22880003	6	pH	14 / 5	8.6	8.14	8.3	0 / NA	0% / NA	NO	Monitored	Full
22880003	6	Temperature	14 / 5	27.2	23.48	23.9	0 / 0	0% / 0%	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 Wet Mass = 75th Percentile	Assessment Type	Support Level
22880003	6	9	256.422	99.1 %	15.208	93.2 %	NO	Evaluated	NA

Class C - Conventional Parameters:

Site ID	Data Source ID	Parameter Name	# Samples / # Years	Maximum Value	Mean Value	Median Value	# Violations	% Violations	Significantly >10% Violations	Assessment Type	Support Level
22880003	6	Inorganic nitrogen (nitrate and nitrite)	14 / 5	1.9	0.56	0.25	0	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

Date

Species Name

Biopart

# in sample

chlordane result

chlordane violation?

PCBs result

PCBs violation?

Hg result

Hg violation?

Assessment Type

Support Level

166

9/27/11

walleye

plug

0.120

Evaluated

Full

166

10/5/10

walleye

fillet

0.653

Yes

Evaluated

Partial

166

10/5/10

channel catfish

fillet

<0.03

<0.09

0.189

Evaluated

Full

Monitoring and Methods

Assessment Key Dates

6/16/2014

Fixed Monitoring Start Date

8/22/2018

Fixed Monitoring End Date

10/5/2010

Fish Tissue Monitoring

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)