Lake Miami IA 04-LDM-1016

Monroe County S20T73NR17W 5 mi. SE of Lovilia.

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.

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Cycle: 2020
Release Status: Final
Overall IR: 5 - Water is impaired or threatened and a TMDL is needed.
Trophic: Hypereutrophic
Trend: Stable
Created: 7/31/2020 2:15:28 PM
Updated: 10/14/2020 10:47:23 AM

Use Support

Class A1

Recreation - Primary contact

Not Supported

Turbidity

Support Level

Not Supported

Impairment Code

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

Cause Magnitude

Moderate

Status

Continuing

Source

Agriculture

Source Confidence

Moderate

Cycle Added

2002

Impairment Rationale

Narrative criteria violation: aesthetically objectionable conditions

Data Source

Ambient monitoring: Iowa DNR-lakes

Class BLW

Aquatic Life - Lakes and wetlands

Partially Supported

Turbidity: Siltation/Turbidity

Support Level

Partially Supported

Impairment Code

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

Cause Magnitude

Moderate

Status

Continuing

Source

Agriculture

Source Confidence

Moderate

Cycle Added

2002

Impairment Rationale

Adverse impacts on plant/animal communities

Data Source

Biological monitoring: Iowa DNR Fisheries

Class HH

Human Health -

Partially Supported

Fish Consumption Advisory: Mercury

Support Level

Partially Supported

Impairment Code

5a - Pollutant-caused impairment. TMDL needed.

Cause Magnitude

High

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

Moderate

Cycle Added

2012

Impairment Rationale

Fish consumption advisory in effect: no more than 1 meal/week

Data Source

Fish contaminant monitoring: Iowa DNR

TMDL Priority

Tier IV

General Use

General Use water -

Not Assessed

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The Class A1 use is assessed (monitored) as “not supported” (IR 4a) due to poor water clarity caused by non-algal turbidity. The Class BLW use is assessed (evaluated) as “partially supported” (IR 4a) due to excessive algal production, reduced water transparency related to the presence of common carp populations, and sedimentation problems in the lake. Class HH use remains assessed (monitored) as “partially supported” (IR 5a) based on the results of fish tissue monitoring. Note: A TMDL for siltation and nutrients at Lake Miami was prepared by DNR and approved by EPA in 2001; thus, this lake was placed into IR Category 4a (TMDL approved) for the 2004 assessment/listing cycle. Because the Section 303(d) impairment for mercury in fish tissue was not addressed by the TMDL, this waterbody will be moved to IR Category 5a (impaired; TMDL needed) for the current assessment/listing cycle.

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	22680001	Lake Miami Max Depth

Class A1 - Indicator Bacteria: No Data

Class A1 - pH:

Site ID	Data Source ID	# Samples / # Years	Maximum Value	Mean Value	Median Value	# Violations	% Violations	Significantly >10% Violations	Assessment Type	Support Level
22680001	6	13 / 5	9.6	8.6	8.4	3	23%	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
22680001	6	Chlorophyll a TSI	13 / 5	36	82	60	NO	Monitored	Full
22680001	6	Secchi TSI	13 / 5	39	77	67	YES	Monitored	Not
22680001	6	Total Phosphorus TSI	13 / 5	52	85	65	NA	NA	NA
22680001	6	Inorganic suspended solids	13 / 5	0.6	15	3.8	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
22680001	6	Ammonia	13 / 5	0.34945	0.07	0.01	0 / 0	0% / 0%	NO	Monitored	Full
22680001	6	Dissolved oxygen	13 / 5	21.3	10.6	11.1	NA / 1	NA / 8%	NO	Monitored	Full
22680001	6	pH	13 / 5	9.6	8.6	8.4	3 / NA	23% / NA	NO	Monitored	Full
22680001	6	Temperature	13 / 5	31	24.7	24.1	0 / 0	0% / 0%	NO	Monitored	Full

Class BLW - Lake Planktonic Cyanobacteria: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
22680001	6	9	72.114	94.1 %	7.351	60.1 %	NO	Evaluated	NA

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

141

7/27/10

largemouth bass

fillet

0.394

Yes

Evaluated

Partial

141

10/26/09

largemouth bass

fillet

0.353

Yes

Evaluated

Partial

Monitoring and Methods

Assessment Key Dates

5/27/2014

Fixed Monitoring Start Date

8/19/2018

Fixed Monitoring End Date

10/26/2009

Fish Tissue Monitoring

7/27/2010

Fish Tissue Monitoring

1/28/2002

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)